Review Article Hsp90 Inhibitors for the Treatment of

Review ArticleHsp90 Inhibitors for the Treatment ofChronic Myeloid Leukemia

Kalubai Vari Khajapeer and Rajasekaran Baskaran

Department of Biochemistry and Molecular Biology School of Life Sciences Pondicherry University Pondicherry 605014 India

Correspondence should be addressed to Rajasekaran Baskaran baskaranrajasekarangmailcom

Received 26 August 2015 Revised 11 November 2015 Accepted 12 November 2015

Academic Editor Massimo Breccia

Copyright copy 2015 K V Khajapeer and R Baskaran This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Chronic myeloid leukemia (CML) is a hematological malignancy that arises due to reciprocal translocation of 31015840 sequences fromc-Abelson (ABL) protooncogene of chromosome 9 with 51015840 sequence of truncated break point cluster region (BCR) on chromosome22 BCR-ABL is a functional oncoprotein p210 that exhibits constitutively activated tyrosine kinase causing genomic alteration ofhematopoietic stem cells BCR-ABL specific tyrosine kinase inhibitors (TKIs) successfully block CML progression However drugresistance owing to BCR-ABL mutations and overexpression is still an issue Heat-shock proteins (Hsps) function as molecularchaperones facilitating proper folding of nascent polypeptides Their increased expression under stressful conditions protects cellsby stabilizing unfolded ormisfolded peptides Hsp90 is the major mammalian protein and is required by BCR-ABL for stabilizationand maturation Hsp90 inhibitors destabilize the binding of BCR-ABL protein thus leading to the formation of heteroproteincomplex that is eventually degraded by the ubiquitin-proteasome pathway Results ofmany novelHsp90 inhibitors that have enteredinto various clinical trials are encouraging The present review targets the current development in the CML treatment by availingHsp90 specific inhibitors

1 Introduction

Leukemia is a type of blood cancer in which unusual raise innumber of white blood cells is found Four types of leukemiaare recognized by most cancer registries [1] They are acutemyeloid leukemia (AML) acute lymphoid leukemia (ALL)chronic myeloid leukemia (CML) and chronic lymphoidleukemia (CLL) CML is a hematoproliferative neoplasmthat is marked by uncontrolled myeloid cell divisions inbone marrow [2] CML is divided into three phasesmdashchronicphase accelerated phase and blast crisis [3] Although foundin all age groups CML more often occurs in middle agedand elderly people with a median age of 67 years [4] CMLaccounts for sim20 of all leukemia cases in adults in westernpopulation [5] Estimated annual prevalence of CML is 1-2per 100000 population with greater frequency in males [6]

The mark of CML is the presence of shortened Philadel-phia chromosome (Ph) that occurs due to reciprocal translo-cation between chromosome 9 and chromosome 22 [(922)(q34q11)] thereby eventually culminating in the genesis ofthe BCR-ABLoncogeneAbout 90ofCMLpatients have Ph

The BCR-ABL oncogene encodes a constitutively activatedtyrosine kinase BCR-ABL Fusion at different break points inBCR gene locus produces 3 different oncoproteins namelyp190 p210 and p230 p190 causes ALL [7] p210 is the majorprotein involved in CML [2] p230 is correlated with a mildform of CML

2 Signaling Pathways Affected by BCR-ABL

BCR-ABL activates several pathways such as RAS a smallGTPase mitogen activated protein kinase (MAPK) signaltransducers and activator of transcription (STAT) and phos-phoinositide 3-kinase (PI3K) pathways that regulate sur-vival proliferation and apoptosis of leukemic cells [8ndash16](Figure 1)

3 Overview of Treatment for CML

Since 1960 antimetabolites like cytarabine busulfan (BUS)and hydroxyurea (HU) were used for the treatment of CML

Hindawi Publishing CorporationLeukemia Research and TreatmentVolume 2015 Article ID 757694 16 pageshttpdxdoiorg1011552015757694

2 Leukemia Research and Treatment

BCR-ABL

CRKSO

SGRB-2CBL CRKL

GAB2 PI3-K

PIP3

AKT

IKKMDM2

p53

p27 STAT5BADERK12

RAS

RAF

MEK12

P P

P PP P

P

P

P

Cytoskeletalproteins

Altered adhesion motility

(a)(b)

(c)

(d)

Survival

Proliferation

P

NF120581B

IKB120572 Bcl-xL

Figure 1 Signaling pathways activated by BCR-ABL (a) BCR-ABL activates GRB-2SOS which in turn activates RAS Active RASactivates RAF Active RAF stimulates MEK1 which in turn activatesERK12 Activation of Ras pathway by BCR-ABL aids CML cellsproliferation On the other hand activated GRB-2SOS stimulatesGAB2 which activates PI3-K pathway (b) BCR-ABL phosphorylatesadaptor proteins like CRK and CRKL leading to the activation ofPI3-K PI3-K phosphorylates PIP2 to PIP3 which in turn activatesAKT AKT inhibits p27 leading to CML cells proliferation AKTphosphorylates MDM2 which in turn inhibit p53 AKT activatesNF120581B via phosphorylation of IKK and IkB120572 AKT inhibits p-BAD Activation of NF120581B and inhibition of p53 and BAD by AKTevade apoptosis and promote CML cells survival (c) BCR-ABLphosphorylates STAT5 which also aid in evading apoptosis of CMLcells (d) BCR-ABL phosphorylate cytoskeleton proteins resultingin increased cellular motility and reduced adhesion to extracellularmatrix of bone marrow

[8] Later in 1970 allogeneic stem cell transplantation inwhich patient receives stem cells from a genetically similardonor was used as an effective therapy for CML But thisapproach was risky due to limited availability of geneticallyidentical persons and caused death in elderly people [17] In1980 interferon-120572 (IFN-120572) proved effective for the treatmentof CML Such treatment prolonged the survival comparedto BUS and HU [18] Later the discovery of tyrosine kinaseinhibitors (TKIs) renewed theCML treatment (Figure 2)withincreased survival rates decreased side effects and improvedlife quality (Table 1)

31 First-Generation TKI Imatinib a 2-phenylaminopyrimi-dine derivative (Figure 2) competes with the ATP binding

site of c-ABL kinase of fusion BCR-ABL found in CML cells[19] Phase-I trials of imatinib showed significant antiprolif-erative activity in CML patients in which IFN-120572 treatmentfailed [20] In addition to ABL imatinib inhibits PDGFRArg and c-Kit except Src kinases Results of InternationalRandomized Study of Interferon and STI571 (IRIS) trialsshowed reliability and supremacy of imatinib related to IFN-120572 in terms of hematologic and cytogenetic responses [21]Imatinib was legalized by the US Food and Drug Admin-istration (FDA) in 2001

32 Resistance of Imatinib Resistance of imatinib is of twotypes BCR-ABL dependent and BCR-ABL independent Theformer is due to mutations in the BCR-ABL kinase domain[22] and overexpression of BCR-ABL protein [23] Pointmutations in the BCR-ABL kinase domain decrease or inhibitthe interaction of TKI with the aberrant BCR-ABLThe mostprevalently observed mutation in CML patients resistant toimatinib is T315I This mutation has isoleucine instead ofthreonine at the 315th amino acid in the BCR-ABL proteinAlterations in critical contact points due to amino acidsubstitutions increase the failure of TKI affinity to the targetsite Amino acid substitutions at 7 residues result inmutationssuch as G250E M244V M351T E255KV F359V Y253FHand T315I To date over 90 point substitution mutations inBCR-ABL kinase domain have been distinguished in drugresistant CML patients There are 4 regions that are essentialfor high frequency binding of imatinib (P-loop SH-3 SH-2and A-loop)The P-loop is responsible for phosphate bindingand mutations in this site were frequently observed in 43of patients who were generally in the acute and blast crisisphases The P-loop mutations E255K and Y253F increase theprobability of transformation depending on BCR-ABL kinaseactivity [24]

BCR-ABL independent resistance is due to LysM-con-taining receptor-like kinase (Lyn kinase) overexpression [25]and activation [26] increased levels of imatinib efflux trans-porters [eg ATP-binding cassette sub-family B multidrugresistance (MDR)] [27] and the multidrug resistant protein 1(MDA-1) [28]

33 Second Generation TKIs To overcome intolerance andimatinib resistance in CML patients development of second-generation TKIs such as dasatinib bosutinib and nilotinibwas unfolded [29] Various clinical studies like Dasatinibversus Imatinib Study in Treatment of Naive CML-ChronicPhase-Patients (DASISION) [30] Evaluating Nilotinib Effi-cacy and Safety in Clinical Trials-Newly Diagnosed Patients(ENESTnd) [31] and Bosutinib Efficacy and Safety in NewlyDiagnosed CML (BELA) [32] trials showed efficacy andsuperiority of second-generation TKIs over first-generationTKI [33]

Dasatinib a thiazolecarboxamide (Figure 2) binds to theBCR-ABLrsquos ATP binding site with more compatibility thanimatinib [34] Dasatinib is capable of binding to both theopen and closed conformations of BCR-ABL whereas ima-tinib binds only to the closed conformation of the BCR-ABL[35] Dasatinib was affirmed by the US FDA in 2007 [36]

Leukemia Research and Treatment 3

Table 1 Anti-CML TKIs

TKIs Compound name Previous name Company Trade name Approval by US FDA DosageFirst-generationTKI

Imatinib STI571 CPG57148B Novartis Gleevac or Glivec 2001 CML-CP-400mgonce daily

Second-generationTKIs

Nilotinib AMN107 Novartis Tasigna 2006CML-

CPAP-400mgtwice daily

Dasatinib BMS354825 Bristol-MyersSquibb Sprycel 2007 CML-CP-100mg

once dailyBosutinib SKI606 Pfizer Bosulif 2012 500mg once daily

Third-generationTKI

Ponatinib AP24534 Ariad Iclusig 2013 45mg once daily

lowastCP chronic phase AP accelerated phase

O

N

N

NN

HH

N

N

N

(a) Imatinib

Me

Me

N

N

N

HO

N N

N NHH

OCl

S

(b) Dasatinib

N NN

HN

NHO

FF

F

NN

(c) Nilotinib

∙H2O

OMe

MeO

ON

NMe

ClCl

HN

CN

N

(d) Bosutinib

OFF

F

N

NN

NH

N

N

(e) Ponatinib

Figure 2 Currently available BCR-ABL specific TKIs for CML treatment (a) First-generation TKI ((b) (c) and (d)) Second-generationTKIs (e) Third-generation TKI


Interestingly dasatinib not only inhibits BCR-ABL and butalso inhibits kinases like Src kinases (Src Lck and YES) c-Kit PDGFR and ephrin-A receptor [37]

Nilotinib an aminopyrimidine (Figure 2) structurallyrelated to imatinib binds exclusively to the closed conforma-tion of BCR-ABLNilotinib hasmore affinity in binding to theATP-binding site of BCR-ABL than imatinib [38] Nilotinibwas approved in 2007 by US FDA as a subsequent treatmentpreference in CML patients in chronic phase following ima-tinib Nilotinib is similar to imatinib in inhibiting PDGFRArg and Kit except Src kinases [39]

According to the instructions of the European Societyfor Medical Oncology and National Comprehensive CancerNetwork Guidelines in Oncology (NCCN) we recommendimatinib dasatinib or nilotinib as first line therapy for latelyfound CML patients in chronic phase [5]

Bosutinib is a 4-anilino-3-quinoline carbonitrile (Figure 2)that inhibits both ABL and Src kinases [40] Bosutinib isrecommended for imatinib resistance CML patients as wellas in recently diagnosed CML patients in chronic phase[41] Importantly low doses of bosutinib inhibit BCR-ABLwhen compared to imatinib Bosutinib is effective againstmost Gleevac resistant mutations except T315I and V299Lsubstitutions [42]

34 Third-Generation TKI BCR-ABL-T315I is the leadingmutation that accounts for resistance to cytotoxic drugs first-and second-generation TKIs To combat imatinib resistancein CML patients third-generation TKIs were developed

Ponatinib (AP24534) is a third-generation TKI (Figure 2)that inhibits both wild type and BCR-ABL harboring muta-tions such as M244V G250E Q252H Y253FH E255KVF317L M351T and F359V Ponatinib is developed to inhibitexclusively T315I mutation of BCR-ABL [43]

4 In Vitro CML Cell Line Model

Currently more than 40 CML derived cell lines have beendocumented Of these K562 is a BCR-ABL positive CML cellline that was established from 53-year-old woman with CMLin blast crisis stage [44] After 176 passages in 35 years K562cell line still has active CML cells in blast crisis stage with Ph[45] In fact CML induction inmice is carried out by injectingK562 cells into their tail vein K562 is well reliable BCR-ABLpositive CMLmodel to test the efficacy of a desired drug [46]

5 Heat Shock Proteins An Overview

Initially discovered in Drosophila by Ritossa in 1996 [47]heat shock proteins (Hsps) function as molecular chaper-ones facilitating proper folding and maturation of nascentpolypeptides [48] Hsps protect against protein aggregationin cytosol [49] Hsps are highly conserved and universallyexpressed in all species from bacteria to plants and animals[50] These are produced by cells under stressful conditionssuch as heat hence the name heat shock proteins Later Hspswere found to be rapidly explicated in response to stressconditions such as hypoxia ischemia hyperoxia anoxia

exposure to UV light nutrient deficiencies (eg glucosedeprivation) and heavy metals [51] Heat shock transcrip-tional factors (HSFs) are protein family that supervises thetranscription of Hsp genes [52] In mammals major HSFsinclude HSF1 HSF2 and HSF4 Of these HSF1 is the mainregulator of Hsps production [53]

Under normal physiological conditions HSF1 remains asamonomer and is tightly bound toHsp90 [54] In response tostress because of increased denatured and improperly foldedproteins in the cell HSF1 dissociates from the Hsp90-HSF1complex ReleasedHSF1 from the cytosol translocates into thenucleus and binds to heat shock response element (HSRE)in DNA and induces the production of Hsps Hsps preventprotein denaturation in cells facing stress conditions [55]

51 Classification of Hsps Based on their molecular weightHsps have been classified into five major classes They aresmall Hsps Hsp60 Hsp70 Hsp90 and Hsp100 Out of theseHsp90 is a major cytosolic protein that constitutes about 1-2 of total cytosolic protein [56] It exhibits four isoformswhich include Hsp90120572 Hsp90120573 glucose-regulated protein-94 (GRP-94) and TNF receptor associated protein-1 (TRAP-1) [57] Of these Hsp90120572 is the major isoform [58]

52 Hsp90 Structure Hsp90 exists as a homodimer It con-sists of three major regionsmdasha 25 kDa N-terminal domain40 kDa middle domain and 12 kDa C-terminal domain [59]In addition a charged linker region between the N-terminaland the middle domain is located The N-terminal domainhas an ATP binding site and shows homology to otherATPasekinases like gyrase histidine kinase and mutL superfamily [60] Various client proteins bind to the middle do-main of Hsp90 [61] C-Domain has an alternate ATP bindingsite At the end of C-terminal a tetratricopeptide repeat(TPR) motif which has a preserved MEEVD pentapeptideintended for Hsp90 interaction with its co-chaperons ispresent [62] Hsp90 mediated protein folding is an ATPdependent process Various cochaperons like cell divisioncontrol protein 37 (cdc37) Hsp organizing protein (Hop)activator of Hsp90 ATPase (Aha1) and p23 and FK506-binding protein 5152 (FKBP5152) aid Hsp90 in the appro-priate folding of client proteins [63]

6 Hsp90 and Cancer

When compared to normal cells cancer cells are underphysiological stress like hypoxia ischemia and nutrientdeficiencies (eg glucose deprivation) Hence production ofHsps is ten times higher in tumor cellsMany proteinsfactorsassociated with the six hallmarks of cancer (Figure 3) such asAkt Src Flt3 cdk4 cdk6 telomerase MEK Raf HIF1 andBCR-ABL are client proteins of Hsp90 [64]

Moreover it is now well documented that Hsp90 is req-uisite for stabilization and proper functioning of thesemultiple mutated cancerous proteins that assist cancer cellgrowth survival and malignancy [65] More than 200 clientproteins including hormone receptors structural proteins[66] tyrosine kinases and transcription factors [67] require


Hsp90

Self-sufficiency in growth signals

ErbB-2 Akt Src MEK)

Evasion of apoptosis

Limitless replicative potential

(n-TERT telomerase)

Insensitivity to antigrowthsignals

Myt-1 Cyclin-D)

Tissue invasion and metastasis

(c-MET MMP2)

Sustained angiogenesis

(Survivin Akt Rip p53Apaf-1 Bcl-2 IGF-IR)

Src FAK)(VEGFR HIF1 Akt Flt3

(EGFR Raf BCR-ABL

(Plk-1 Cdk4 Cdk6

Figure 3 Relationship between Hsp90 and various client proteins resulting in cancer cell survival progression invasion and metastasis

Hsp90 for proper functioning and facilitating growth andsurvival [68] Cancer cells exploit Hsp90 to back these acti-vated oncoproteins that are foremost for oncogenic alterationIn this manner Hsp90 assist cancer cells to survive in aninhospitable environment [69] A specific role of Hsp90 inmaintenance of tumor cell is to inhibit apoptosis [70]

7 Hsp90 and CML

In normal cells Hsp90 levels are low whereas in CMLcells Hsp90 levels are elevated Hence elevated Hsp90 levelscould serve as prognostic marker in CML [71] IncreasedHsp90 protect fusion oncoprotein BCR-ABL by inhibitingits degradation (Figure 4(a)) In this way Hsp90 preventCML cells from apoptosis and promote cell survival andprogression Blocking the binding of BCR-ABL to Hsp90through Hsp90 inhibitors causes BCR-ABL degradation viaubiquitin proteasomal pathway (Figure 4(b)) (Table 2)

71 Hsp90 Inhibitors from Microbial Origin

711 Benzoquinone Ansamycin Derivatives Geldanamycin(GDA) was isolated from Streptomyces hygroscopicus [72]GDA is a benzoquinone ansamycin antibiotic that binds tothe N-terminal domain of Hsp90 and inhibits its activity(Figure 5) GDA is poorly soluble in water and highly hepat-otoxic due to the presence of methyl group at C-17 Ana-logues of GDA 17-allylamino-17-demethoxygeldanamycin(17AAG) or tanespimycin and 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17DMAG) or alvespimycin(Figure 5) were consequently synthesized 17AAG is more

soluble and showed more potent activity than GDA [73]Both GDA and 17AAG lowered BCR-ABL levels and leadCML cells to apoptosis In addition to BCR-ABL GDAlowered cellular levels of c-Raf and Akt [74] 17DMAGshowed higher potency more bioavailability and less toxicitycompared to 17AAG and has entered into clinical trials [75]17DMAG along with PD184352 a mitogen protein kinaseinhibitor downregulated ERK12 and Bcl-xL levels andcaused apoptosis in CML cells sensitive as well as resist-ant to imatinib [76] The synergistic effect of LBH589 ahistone deacetylase inhibitor and 17AAG downregulated p-Flt3 p-Akt p-ERK12 and BCR-ABL levels in CML cells [77]The combinational treatment of 17AAG and histone dea-cetylase inhibitor suberoylanilide hydroxamic acid causedmitochondrial damage activated caspases 3 and 9 andinduced apoptosis in CML cells It also lowered Mcl-1 Raf-1p27 p34 and p-ERK12 levels [78]

Ganetespib (STA-9090) is a non-geldanamycin resorcinolcontaining triazolone (Figure 5) that is presently in phase IIclinical trials for the treatment of solid tumor and hematolog-ical malignancy [79] Ganetespib inhibits Hsp90 activity byblocking the coupling of p23 cochaperone to Hsp90 Ganete-spib (IC

50is 2ndash30 nM) ismore potent than 17AAG(IC

50is 20ndash

3500 nM) and caused cell death in non-small cell lung cancer(NSCLC) models [80] Ganetespib showed potent activityagainst primary AML cells and also in combination withcytarabine caused significant cell death [81]

Herbimycin A is a 19-membered macrocyclic lactam(Figure 5) isolated from Streptomyces hygroscopicus [82] Her-bimycin A exhibits herbicidal antifungal antiangiogenicand antitumor activities Herbimycin A modulates Hsp90thus interrupting it from coupling to its client proteins [83]


BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP

Cell growth and survival

M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL

Ubiquitin proteasomedegradation of BCR-

ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)

Figure 4 BCR-ABL functioning in the presence and absence of Hsp90 inhibitors (a) In CML cells Hsp90 levels are elevated Henceoncoprotein BCR-ABL binds to Hsp90 for stabilization and maturation Hence stabilized BCR-ABL then activates many signaling pathwaysleading to CML cells survival progression and malignancy (b) Blocking Hsp90 chaperone activity by employing Hsp90 inhibitors results inBCR-ABL degradation via ubiquitin proteasome pathway

The synergistic effect of herbimycin A and TKI made CMLcells more susceptible to apoptosis [84]

Macbecin I and Macbecin II (Figure 5) isolated fromNocardia species belong to benzoquinone ansamycin group[85] Macbecin sticks to the ATP binding site of N-terminalof Hsp90 Macbecin is more stable and soluble than GDAMacbecin I exhibited cytotoxic and antitumor activitiesagainst leukemia P388 melanoma B16 and Ehrlich carci-noma in mice [86]

712 Radicicol Radicicol is a 14-membered macrolide(Figure 5) isolated from Diheterospora chlamydosporia andMonosporium bonorden Like GDA radicicol binds to theATP binding site located at the N-terminus of Hsp90 [87]Radicicol lacks in vivo anticancer activity as it is convertedto inactive metabolites in vivo To overcome this oximederivatives of radicicol such as KF25706 KF29518 andKF58333 (Figure 5) were synthesized [88] Among theseKF25706 destabilizes interaction between Hsp90 and itsassociated molecules [89] Radicicol decreased phosphor-ylated Raf-1 and BCR-ABL protein levels in CML cells Rad-icicol also caused BCR-ABL inactivation viaHsp90 inhibitionin K562 cells [90]

713 Coumermycin Family Novobiocin (NB) Coumermy-cin A1 (Figure 5) and Clorobiocin belong to the coumermy-cin antibiotic family They were isolated from Streptomycesspheroids NB binds avidly to the C-terminal of Hsp90 andinhibits its activity [91] NB reduced p-Akt p-ERK and p-BCR-ABL levels in CML cells NB also decreased the couplingof BCR-ABL to Hsp90 and caused BCR-ABL degradation viaproteasome-ubiquitin pathway in K562 cells Moreover NBnot only inhibited proliferations but also lowered levels ofBCR-ABL in K562 cells resistant to imatinib [92]

72 Hsp90 Inhibitors from Plant Origin

721 Epigallocatechin-3-gallate (EGCG) EGCG is a polyphe-nol compound (Figure 6) isolated from green tea Camelliasinensis [93] EGCG is a C-terminus inhibitor and suppressesHsp90 activity [94 95] In combination with ponatinibEGCG induced significant apoptosis in CML cells CyclinD1and CDC25A levels were downregulated by this treatment inCML cells [96]

722 Taxol Taxol (Figure 6) isolated from Taxus baccataL [97] agent stabilizes microtubule formation and induces


Table 2 BCR-ABL signaling pathways affected by Hsp90 inhibitors

S number Name of thecompound Isolated from Nature of

originMechanism of inhibition of

Hsp90

Signaling proteindownregulated byHsp90 inhibitors

References

1 Geldanamycin Streptomyceshygroscopicus Bacterial Binds to N-terminal

domain of Hsp90

darr c-Rafdarr Aktdarr BCR-ABL

[74]

2 RadicicolDiheterospora

chlamydosporia andMonosporium bonorden

Fungal Binds to N-terminaldomain of Hsp90

darr p-Raf1darr p-BCR-

ABL[90]

3 Novobiocin Streptomyces spheroids Bacterial Binds to C-terminaldomain of Hsp90

darr p-Aktdarr p-ERK ampdarr p-BCR-

ABL

[91 92]

4 Epigallocatechin-3-gallate Camellia sinensis Plant Binds to C-terminal

domain of Hsp90darr CyclinD1darr CDC25A [96]

5 Taxol Taxus baccata L Plant NYK

darr pSTAT3darr pSTAT5darr p-CRKLdarr p-Lyn

[101]

6 Gambogic acid Garcinia hanburyi Plant Binds to N-terminaldomain of Hsp90

darr p-BCR-ABLdarr pSTAT5darr p-CRKLdarr pERK12darr p-Akt ampdarr p-BCR-

ABL

[103 104]

7 Celastrol Tripterygium wilfordiiHook F Plant Disrupts binding of Cdc37

to Hsp90

darr pSTAT5darr p-CRKLdarr pERK12darr p-Aktdarr p-BCR-ABLdarr Bcl-xLdarrMcl-1darr survivin

[107 108]

8 CurcuminCurcuma aromaticaCurcuma longa andCurcuma phaeocaulis

Plant NYK

darr BCR-ABLdarr CRKLdarr STAT5

[110 111]

9 Withaferin A Withania somnifera Plant Disrupts the binding ofCdc37 to Hsp90

darr NF120581Bdarr Bcl-2darr Bimdarr p-Bad

[114 115]

10 5-Episinuleptolideacetate Sinularia species Coral NYK

darr c-ABLdarr Aktdarr NF120581B

[116]

lowastNYK not yet known

apoptosis via mitotic catastrophe [98] Taxol inhibits Hsp90activity [99 100] Synergistic effect of paclitaxel and borte-zomib a proteasome inhibitor reduced the autophospho-rylated levels of BCR-ABL Moreover this combinationaltreatment attenuated BCR-ABL downstream signaling path-ways decreasing phosphorylated STAT3 STAT5 CRKL andLyn levels It also activates caspases 3 8 and 9 causing

apoptosis of CML cells via poly(ADP-Ribose) polymerase(PARP) cleavage [101]

723 Gambogic Acid (GA) GA is a main component of(Figure 6) Chinese plantGarcinia hanburyi (gamboge) [102]GA binds to N-terminus of Hsp90 and inhibits its activityGA was approved by China FDA and entered into phase-II


N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin

Figure 5 Hsp90 inhibitors of microbial origin


HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A

Figure 6 Hsp90 inhibitors of plant origin

clinical trials GA deregulates the expression of Src-3 Aktand VEGFR2 resulting in the apoptosis of tumor cells[103] GA not only induced apoptosis but also reduced cellproliferation in CML cells GA lowered BCR-ABL levels inwild and resistant CML cells in vivo GA decreased the levelsof p-STAT5 p-CRKL p-ERK12 and p-Akt [104]

724 Celastrol Celastrol is a quinone methide triterpene(Figure 6) isolated from the poisonous plant Tripterygiumwilfordii Hook F (Thunder God Vine) Celastrol is used inthe medication against inflammation asthma and allergicconditions [105] Celastrol disrupts the binding of Cdc37 to

Hsp90 thus inhibiting its activity [106] Importantly celastroltriggers the degradation of BCR-ABL and Flt3 [107] Bothin vitro and in vivo studies showed that celastrol decreasedphosphorylated BCR-ABL Akt Erk12 and STAT5 proteinlevels Celastrol also lowered antiapoptotic (Bcl-xL Mcl-1and survivin) protein levels and induced apoptosis in CMLcells harboring T135I mutation [108]

725 Curcumin Curcumin isolated from Curcuma plantspecies (Figure 6) like Curcuma aromatica Curcuma longaand Curcuma phaeocaulis exhibits antioxidant anti-inflam-matory and antitumor activities Several lines of studies


O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH

5-Episinuleptolide acetate

Figure 7 Hsp90 inhibitors of coral origin

demonstrated the antileukemic activity on ALL cells both invitro and in vivo Curcumin inhibits ABL STAT Akt andmTOR signaling pathways causing apoptosis of CML cells[109] Curcumin inhibits Hsp90 activity [110] C817 a novelderivative of curcumin inhibits both wild and mutant ABLkinase activities (Q252HY253F andT315I) In addition C817downregulates phosphorylated BCR-ABL CRKL and STAT5protein levels [111]

726 Withaferin A Withaferin A is a steroidal lactone(Figure 6) isolated from the Indian medicinal plant Ash-wagandha (Withania somnifera) [112] Withaferin A inter-feres with Hsp90-Cdc37 chaperone complex by regulatingleucine rich repeat kinase 2 (LRRK2) levels [113] WithaferinA reduced the levels of NF120581B and potently inhibited thegrowth of human and murine B cell lymphoma cell lines[114] Withaferin A induced caspase activation and causedapoptosis in doxorubicin-sensitive K562 and doxorubicin-resistant K562Adr cells Moreover it downregulated Bcl-2Bim p-Bad and cytoskeletal tubulin protein levels HenceWithaferin A overcomes the MDR caused by the overexpres-sion of P-glycoprotein (P-gp) in K562 levels with attenuatedapoptosis [115]

73 Hsp90 Inhibitors from Coral Origin

731 5-Episinuleptolide Acetate (5EPA) 5EPA is a macro-cyclic 3(2H)-furanone-based norcembranoidal diterpene(Figure 7) isolated from the formosan soft coral Sinulariaspecies 5EPA exhibits antiproliferative activity against K562HL60 and Molt4 cancer cell lines 5EPA also lowered c-ABLAkt and NF120581B levels in CML cells 5EPA induced apoptosisin leukemic cells via Hsp90 inhibition [116]

8 Evaluation of Hsp90 Functionor Hsp90 Inhibition

Hsp90 function or inhibition could be evaluated by the fol-lowing assays They are as follows

81 Coupled Enzyme Assay Hsp90 requires ATP for itsmolecular chaperone activity [63] The ADP generated byHsp90 is coupledwith phosphoenol pyruvate to generateATPand pyruvate catalyzed by pyruvate kinase enzyme Thenpyruvate is converted into lactate by lactate dehydogenaseenzyme with the expenditure of NADH This assay is doneto assess the ATPase activity of Hsp90 In this assay forevery ADP generated by Hsp90 one NADH is consumed(Figure 8(a)) Low NADH levels lead to the decrease in UVabsorbance at 340 nm [117]

82 Malachite-Green Assay This assay is also designed toevaluate the ATPase activity of Hsp90 [63] The cationicdyemalachite-green alongwith the phosphomolybdate reactswith inorganic phosphate released to give a blue color havingabsorption maxima at 610 nm [118 119]

83 Hsp90 Inhibition Using Western Blotting Hsp90 inhibi-tion leads to the depletion of Hsp90 levels and its associatedmolecules in cells The decreased Hsp90 levels could beobserved by employing western blotting and densitometrystudies [117]

84 Luciferase Refolding Assay Luciferase is a biolumines-cent photoprotein enzyme derived from firefly Photinuspyralis Luciferase catalyzes the reaction of luciferin with ATPforming luciferyl adenylate which in turn reacts with oxygengiving oxyluciferin This reaction emits light [120] In thisassay the capability of a drug to inhibit Hsp90 is evaluated(Figure 8(b)) Denatured luciferase along with rabbit reticu-locyte lysate (rich source of Hsp90 and its cochaperons) isincubatedThe desired drug molecule is also incubated alongwith the above two If the drug molecule is effective it willinhibit the refolding of luciferase by Hsp90 [121]

9 Hsp90 Inhibitors in Clinical Trials

Of the several Hsp90 inhibitors identified 17-AAG(NCT00100997) is currently under phase I clinical trial spon-sored by JonssonComprehensive Cancer Center collaboratedwith National Cancer Institute (NCI) [122] Efforts areundergoing to determine the side effects and best dose of17-AAG in treating patients with CML in chronic phasethat did not respond to imatinib mesylate Ganetespib(NCT00964873) is in phase I clinical study to assess thesafety and efficacy of once-weekly administered STA-9090in patients with AML ALL and blast-phase CML Thisstudy is sponsored by Synta Pharmaceuticals Corporation[123] Paclitaxel (NCT00003230) is under Phase III trials tostudy the effectiveness in treating patients with refractory orrecurrent acute leukemia or CMLThis work is sponsored bySwiss Group for Clinical Cancer Research [124]

10 Conclusions

CML is a haematological malignancy that arises due to chro-mosomal translocation resulting in the presence of Ph chro-mosome Initially TKIs were designed to compete with theATP binding site of BCR-ABL TKIs effectively inhibited wild


ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)

Denatured luciferase

Refolded luciferase

Luciferin ATPLuciferyladenylate

Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)

Figure 8 (a) Coupled enzyme assay (b) Luciferase refolding assay

BCR-ABL however mutations in BCR-ABL and overexpres-sion following treatment decreased their potency SpecificallyT315Imutation displayed resistance to both first- and second-generation TKIs Eventually ponatinib was developed toinhibit mutant T315I and was approved by the US FDA butwas withdrawn due to toxicity

Presently there is a need for alternative strategy todevelop new BCR-ABL inhibitors Hsp90 is upregulated inCML cells for rapid proliferation survival and progressiontowards malignancy Several Hsp90 inhibitors have beenshown to inhibit and degrade BCR-ABL In vitro studiesunveiled that Hsp90 inhibitors alone or in combination withother inhibitors downregulate BCR-ABL levels in wild-typeandTKI-resistant CML cellsThus suppressing the BCR-ABLprotein levels through Hsp90 inhibition renders an attractivealternate strategy to combat CML

Abbreviations

CLL Chronic lymphoid leukemiaALL Acute lymphoid leukemia

CML Chronic myeloid leukemiaAML Acute myeloid leukemiaPh Philadelphia chromosomeABL c-AbelsonBCR Break point cluster regionMAPK Mitogen-activated protein kinaseSTAT Signal transducers and activator of

transcriptionPI3K Phosphoinositide 3-kinasesBUS BusulfanHU HydroxyureaIFN-120572 Interferon-120572TKI Tyrosine kinase inhibitorsIRIS International Randomized Study of

Interferon and STI571FDA Food and Drug AdministrationLyn kinase LysM-containing receptor-like kinaseMDR Multidrug resistanceMDA-1 Multidrug resistant protein 1DASISION Dasatinib versus Imatinib Study In

Treatment of Naive CML-CP patients


ENESTnd Evaluating Nilotinib Efficacy and Safety inClinical Trials-Newly Diagnosed Patients

BELA Bosutinib Efficacy and Safety in NewlyDiagnosed CML

NCCN National Comprehensive Cancer NetworkGuidelines in Oncology

Hsps Heat shock proteinsHSFs Heat shock transcriptional factorsHSRE Heat shock Response ElementTPR Tetratricopeptide repeatGRP-94 Glucose-regulated protein-94TRAP-1 TNF receptor associated protein-1cdc37 Cell division control protein 37Hop Hsp organizing proteinAha1 Activator of Hsp90 ATPaseFKBP5152 FK506-binding protein 5152GDA Geldanamycin17AAG 17-Allylamino-17-demethoxygeldanamycin17DMAG 17-Dimethylaminoethylamino-17-

demethoxygeldanamycinNSCLC Non-small cell lung cancerNB NovobiocinEGCG Epigallocatechin-3-gallatePARP Poly(ADP-Ribose) polymeraseGA Gambogic acidLRRK2 Leucine rich repeat kinase 25EPA 5-Episinuleptolide acetateP-gp P-GlycoproteinNCI National Cancer Institute

Conflict of Interests

The authors declare that they do not have any competinginterests

Authorsrsquo Contributions

All authors have equally contributed to drafting the paper Allauthors read and approved the final paper

References

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[2] S Shahrabi S Azizidoost M Shahjahani F Rahim A Ahmad-zadeh and N Saki ldquoNew insights in cellular and molecularaspects of BM niche in chronic myelogenous leukemiardquo TumorBiology vol 35 no 11 pp 10627ndash10633 2014

[3] A Tefferi ldquoClassification diagnosis andmanagement of myelo-proliferative disorders in the JAK2V617F erardquo Hematology pp240ndash245 2006

[4] J Chi C Pierides A Mitsidou A Miltiadou P Gerasimouand P Costeas ldquocDNA synthesis for BCR-ABL1 detection atthe MMR level the importance of using the appropriate kitrdquoBiological Procedures Online vol 17 article 4 2015

[5] E J Jabbour J E Cortes and H M Kantarjian ldquoTyrosinekinase inhibition a therapeutic target for the management of

chronic-phase chronic myeloid leukemiardquo Expert Review ofAnticancer Therapy vol 13 no 12 pp 1433ndash1452 2013

[6] X An A K Tiwari Y Sun P-R Ding C R Ashby and Z-SChen ldquoBCR-ABL tyrosine kinase inhibitors in the treatment ofPhiladelphia chromosome positive chronicmyeloid leukemia areviewrdquo Leukemia Research vol 34 no 10 pp 1255ndash1268 2010

[7] M W N Deininger J M Goldman and J V Melo ldquoThemolecular biology of chronic myeloid leukemiardquo Blood vol 96no 10 pp 3343ndash3356 2000

[8] M Sattler and J D Griffin ldquoMolecular mechanisms of transfor-mation by the BCR-ABL oncogenerdquo Seminars in Hematologyvol 40 supplement 2 pp 4ndash10 2003

[9] D W Sternberg and D G Gilliland ldquoThe role of signal trans-ducer and activator of transcription factors in leukemogenesisrdquoJournal of Clinical Oncology vol 22 no 2 pp 361ndash371 2004

[10] F Gesbert and J D Griffin ldquoBcrAbl activates transcription ofthe Bcl-X gene through STAT5rdquo Blood vol 96 no 6 pp 2269ndash2276 2000

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[12] M Karin Y Cao F R Greten and Z-W Li ldquoNF-120581B in cancerfrom innocent bystander to major culpritrdquo Nature ReviewsCancer vol 2 no 4 pp 301ndash310 2002

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[15] P J Roberts and C J Der ldquoTargeting the Raf-MEK-ERKmitogen-activated protein kinase cascade for the treatment ofcancerrdquo Oncogene vol 26 no 22 pp 3291ndash3310 2007

[16] J Downward ldquoTargeting RAS signalling pathways in cancertherapyrdquo Nature Reviews Cancer vol 3 no 1 pp 11ndash22 2003

[17] J M Goldman and J V Melo ldquoChronic myeloid leukemiamdashadvances in biology and new approaches to treatmentrdquoTheNewEngland Journal of Medicine vol 349 no 15 pp 1451ndash14642003

[18] M Talpaz R Hehlmann A Quintas-Cardama J Mercer andJ Cortes ldquoRe-emergence of interferon-120572 in the treatment ofchronic myeloid leukemiardquo Leukemia vol 27 no 4 pp 803ndash812 2013

[19] T Sacha ldquoImatinib in chronic myeloid leukemia an overviewrdquoMediterranean Journal of Hematology and Infectious Diseasesvol 6 no 1 2014

[20] M Dimou and P Panayiotidis ldquoTyrosine kinase inhibitors andinterferonrdquoMediterranean Journal of Hematology and InfectiousDiseases vol 6 no 1 Article ID e2014006 2014

[21] S GOrsquoBrien F Guilhot R A Larson et al ldquoImatinib comparedwith interferon and low-dose cytarabine for newly diagnosedchronic-phase chronic myeloid leukemiardquo The New EnglandJournal of Medicine vol 348 no 11 pp 994ndash1004 2003

[22] M E Gorre M Mohammed K Ellwood et al ldquoClinical resist-ance to STI-571 cancer therapy caused by BCR-ABL genemutation or amplificationrdquo Science vol 293 no 5531 pp 876ndash880 2001

[23] P le Coutre E Tassi M Varella-Garcia et al ldquoInduction ofresistance to the Abelson inhibitor STI571 in human leukemiccells through gene amplificationrdquo Blood vol 95 no 5 pp 1758ndash1766 2000


[24] E J Jabbour J E Cortes and H M Kantarjian ldquoResistanceto tyrosine kinase inhibition therapy for chronic myeloge-nous leukemia a clinical perspective and emerging treatmentoptionsrdquo Clinical Lymphoma Myeloma and Leukemia vol 13no 5 pp 515ndash529 2013

[25] N J Donato J Y Wu J Stapley et al ldquoBCR-ABL indepen-dence and LYN kinase overexpression in chronic myelogenousleukemia cells selected for resistance to STI571rdquo Blood vol 101no 2 pp 690ndash698 2003

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[31] H M Kantarjian A Hochhaus G Saglio et al ldquoNilotinibversus imatinib for the treatment of patients with newlydiagnosed chronic phase Philadelphia chromosome-positivechronic myeloid leukaemia 24-month minimum follow-up ofthe phase 3 randomised ENESTnd trialrdquo The Lancet Oncologyvol 12 no 9 pp 841ndash851 2011

[32] C Gambacorti-Passerini J E Cortes J H Lipton et al ldquoSafetyof bosutinib versus imatinib in the phase 3 BELA trial in newlydiagnosed chronic phase chronic myeloid leukemiardquo AmericanJournal of Hematology vol 89 no 10 pp 947ndash953 2014

[33] R Ferdinand S A Mitchell S Batson and I Tumur ldquoTreat-ments for chronic myeloid leukemia a qualitative systematicreviewrdquo Journal of Blood Medicine vol 3 pp 51ndash76 2012

[34] M Breccia A Salaroli M Molica and G Alimena ldquoSystematicreview of dasatinib in chronic myeloid leukemiardquo OncoTargetsand Therapy vol 6 pp 257ndash265 2013

[35] M Steinberg ldquoDasatinib a tyrosine kinase inhibitor for thetreatment of chronic myelogenous leukemia and philadelphiachromosome-positive acute lymphoblastic leukemiardquo ClinicalTherapeutics vol 29 no 11 pp 2289ndash2308 2007

[36] R Chen and B Chen ldquoThe role of dasatinib in the managementof chronic myeloid leukemiardquo Drug Design Development andTherapy vol 9 pp 773ndash779 2015

[37] P P Piccaluga S Paolini and G Martinelli ldquoTyrosine kinaseinhibitors for the treatment of Philadelphia chromosome-positive adult acute lymphoblastic leukemiardquo Cancer vol 110no 6 pp 1178ndash1186 2007

[38] D L DeRemer C Ustun and K Natarajan ldquoNilotinib asecond-generation tyrosine kinase inhibitor for the treatment ofchronic myelogenous leukemiardquo Clinical Therapeutics vol 30no 11 pp 1956ndash1975 2008

[39] P P Piccaluga S Paolini C Bertuzzi A de Leo and GRosti ldquoFirst-line treatment of chronic myeloid leukemia with

nilotinib critical evaluationrdquo Journal of Blood Medicine vol 3pp 151ndash156 2012

[40] G Keller-von Amsberg and P Schafhausen ldquoBosutinib inthe management of chronic myelogenous leukemiardquo BiologicsTargets and Therapy vol 7 no 1 pp 115ndash122 2013

[41] G K-V Amsberg and S Koschmieder ldquoProfile of bosutiniband its clinical potential in the treatment of chronic myeloidleukemiardquo OncoTargets and Therapy vol 6 pp 99ndash106 2013

[42] S Isfort G Keller-v Amsberg P Schafhausen S Koschmiederand TH Brummendorf ldquoBosutinib a novel second-generationtyrosine kinase inhibitorrdquo in Small Molecules in Oncology vol201 of Recent Results in Cancer Research pp 81ndash97 SpringerBerlin Germany 2014

[43] C L Shamroe and J M Comeau ldquoPonatinib a new tyrosinekinase inhibitor for the treatment of chronic myeloid leukemiaand Philadelphia chromosome-positive acute lymphoblasticleukemiardquo The Annals of Pharmacotherapy vol 47 no 11 pp1540ndash1546 2013

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[48] J Frydman ldquoFolding of newly translated proteins in vivo therole of molecular chaperonesrdquo Annual Review of Biochemistryvol 70 pp 603ndash647 2001

[49] H H Kampinga ldquoChaperones in preventing protein denat-uration in living cells and protecting against cellular stressrdquoin Molecular Chaperones in Health and Disease vol 172 ofHandbook of Experimental Pharmacology pp 1ndash42 SpringerBerlin Germany 2006

[50] C Soti E Nagy Z Giricz L Vıgh P Csermely and P Ferdi-nandy ldquoHeat shock proteins as emerging therapeutic targetsrdquoBritish Journal of Pharmacology vol 146 no 6 pp 769ndash7802005

[51] C Jolly and R I Morimoto ldquoRole of the heat shock responseand molecular chaperones in oncogenesis and cell deathrdquo Jour-nal of theNational Cancer Institute vol 92 no 19 pp 1564ndash15722000

[52] R I Morimoto M P Kline D N Bimston and J J Cotto ldquoTheheat-shock response regulation and function of heat-shockproteins andmolecular chaperonesrdquo Essays in Biochemistry vol32 pp 17ndash29 1997

[53] M V Powers and P Workman ldquoInhibitors of the heat shockresponse biology and pharmacologyrdquo FEBS Letters vol 581 no19 pp 3758ndash3769 2007

[54] Y Hu and N F Mivechi ldquoHSF-1 interacts with Ral-bindingprotein 1 in a stress-responsive multiprotein complex withHSP90 in vivordquoThe Journal of Biological Chemistry vol 278 no19 pp 17299ndash17306 2003

[55] A A Khalil N F Kabapy S F Deraz andC Smith ldquoHeat shockproteins in oncology diagnostic biomarkers or therapeutictargetsrdquo Biochimica et Biophysica Acta vol 1816 no 2 pp 89ndash104 2011


[56] M Yonehara Y Minami Y Kawata J Nagai and I YaharaldquoHeat-induced chaperone activity of HSP90rdquo The Journal ofBiological Chemistry vol 271 no 5 pp 2641ndash2645 1996

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[58] P Csermely T Schnaider C Soti Z Prohaszka and G NardaildquoThe 90-kDa molecular chaperone family structure func-tion and clinical applications A comprehensive reviewrdquo Phar-macology andTherapeutics vol 79 no 2 pp 129ndash168 1998

[59] L H Pearl and C Prodromou ldquoStructure and mechanism ofthe Hsp90 molecular chaperone machineryrdquo Annual Review ofBiochemistry vol 75 pp 271ndash294 2006

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[61] J Fontana D Fulton Y Chen et al ldquoDomain mapping studiesreveal that the M domain of hsp90 serves as a molecular scaf-fold to regulate Akt-dependent phosphorylation of endothelialnitric oxide synthase and NO releaserdquoCirculation Research vol90 no 8 pp 866ndash873 2002

[62] A Carrello E Ingley R F Minchin S Tsai and T RatajczakldquoThe common tetratricopeptide repeat acceptor site for steroidreceptor-associated immunophilins and Hop is located in thedimerization domain of Hsp90rdquo The Journal of BiologicalChemistry vol 274 no 5 pp 2682ndash2689 1999

[63] L H Pearl C Prodromou and P Workman ldquoThe Hsp90molecular chaperone an open and shut case for treatmentrdquoTheBiochemical Journal vol 410 no 3 pp 439ndash453 2008

[64] DHanahan andRAWeinberg ldquoThehallmarks of cancerrdquoCellvol 100 no 1 pp 57ndash70 2000

[65] H Zhang and F Burrows ldquoTargeting multiple signal trans-duction pathways through inhibition of Hsp90rdquo Journal ofMolecular Medicine vol 82 no 8 pp 488ndash499 2004

[66] M Taipale D F Jarosz and S Lindquist ldquoHSP90 at the hubof protein homeostasis emerging mechanistic insightsrdquo NatureReviews Molecular Cell Biology vol 11 no 7 pp 515ndash528 2010

[67] K Richter PMuschler O Hainzl and J Buchner ldquoCoordinatedATP hydrolysis by the Hsp90 Dimerrdquo The Journal of BiologicalChemistry vol 276 no 36 pp 33689ndash33696 2001

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[69] G Jego A Hazoume R Seigneuric and C Garrido ldquoTargetingheat shock proteins in cancerrdquoCancer Letters vol 332 no 2 pp275ndash285 2013

[70] LNeckers ldquoHsp90 inhibitors as novel cancer chemotherapeuticagentsrdquo Trends in Molecular Medicine vol 8 no 4 pp S55ndashS612002

[71] M Zackova D Mouckova T Lopotova Z Ondrackova HKlamova and J Moravcova ldquoHsp90mdasha potential prognosticmarker in CMLrdquo Blood Cells Molecules and Diseases vol 50no 3 pp 184ndash189 2013

[72] C DeBoer P A Meulman R J Wnuk and D H PetersonldquoGeldanamycin a new antibioticrdquoThe Journal of Antibiotics vol23 no 9 pp 442ndash447 1970

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[74] R Nimmanapalli E OrsquoBryan and K Bhalla ldquoGeldanamycinand its analogue 17-allylamino-17-demethoxygeldanamycinlowers Bcr-Abl levels and induces apoptosis and differentiationof Bcr-Abl-positive human leukemic blastsrdquo Cancer Researchvol 61 no 5 pp 1799ndash1804 2001

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[77] P George P Bali S Annavarapu et al ldquoCombination of thehistone deacetylase inhibitor LBH589 and the hsp90 inhibitor17-AAG is highly active against human CML-BC cells and AMLcells with activating mutation of FLT-3rdquo Blood vol 105 no 4pp 1768ndash1776 2005

[78] M Rahmani C Yu Y Dai et al ldquoCoadministration of theheat shock protein 90 antagonist 17-allylamino-17-demethox-ygeldanamycin with suberoylanilide hydroxamic acid or so-dium butyrate synergistically induces apoptosis in humanleukemia cellsrdquo Cancer Research vol 63 no 23 pp 8420ndash84272003

[79] W Ying Z Du L Sun et al ldquoGanetespib a unique triazolone-containing Hsp90 inhibitor exhibits potent antitumor activityand a superior safety profile for cancer therapyrdquo MolecularCancer Therapeutics vol 11 no 2 pp 475ndash484 2012

[80] T Shimamura S A Perera K P Foley et al ldquoGanetespib (STA-9090) a nongeldanamycin HSP90 inhibitor has potent antitu-mor activity in in vitro and in vivomodels of non-small cell lungcancerrdquo Clinical Cancer Research vol 18 no 18 pp 4973ndash49852012

[81] M Lazenby R Hills A Burnett and J Zabkiewicz ldquoTheHSP90 inhibitor ganetespib a potential effective agent forAcuteMyeloid Leukemia in combination with cytarabinerdquo LeukemiaResearch vol 39 no 6 pp 617ndash624 2015

[82] Y Uehara ldquoNatural product origins of Hsp90 inhibitorsrdquo Cur-rent Cancer Drug Targets vol 3 no 5 pp 325ndash330 2003

[83] S Canova V Bellosta A Bigot P Mailliet S Mignani and JCossy ldquoTotal synthesis of herbimycin ArdquoOrganic Letters vol 9no 1 pp 145ndash148 2007

[84] H Ren S Chen and D Lu ldquoEffect of combination of her-bimycin A an inhibitor of tyrosine kinase and chemotherapeu-tic agents on apoptosis of K562 cellsrdquo Zhonghua Xue Ye Xue ZaZhi vol 18 no 5 pp 227ndash230 1997

[85] C J Martin S Gaisser I R Challis et al ldquoMolecular character-ization of macbecin as an Hsp90 inhibitorrdquo Journal of MedicinalChemistry vol 51 no 9 pp 2853ndash2857 2008

[86] Y Ono Y Kozai and K Ootsu ldquoAntitumor and cytocidalactivities of a newly isolated benzenoid ansamycin macbecin-Irdquo Gan vol 73 no 6 pp 938ndash944 1982

[87] T W Schulte S Akinaga S Soga et al ldquoAntibiotic radicicolbinds to the N-terminal domain of Hsp90 and shares important


biologic activities with geldanamycinrdquo Cell Stress and Chaper-ones vol 3 no 2 pp 100ndash108 1998

[88] S Soga Y Shiotsu S Akinaga and S V Sharma ldquoDevelopmentof radicicol analoguesrdquo Current Cancer Drug Targets vol 3 no5 pp 359ndash369 2003

[89] S Soga L M Neckers T W Schulte et al ldquoKF25706 a noveloxime derivative of radicicol exhibits in vivo antitumor activityvia selective depletion of Hsp90 binding signaling moleculesrdquoCancer Research vol 59 no 12 pp 2931ndash2938 1999

[90] F Morceau I Buck M Dicato and M Diederich ldquoRadicicol-mediated inhibition of Bcr-Abl in K562 cells induced p38-MAPK dependent erythroid differentiation and PU1 down-regulationrdquo BioFactors vol 34 no 4 pp 313ndash329 2008

[91] M G Marcu A Chadli I Bouhouche M Catelli and L MNeckers ldquoThe heat shock protein 90 antagonist novobiocininteracts with a previously unrecognized ATP-binding domainin the carboxyl terminus of the chaperonerdquo The Journal ofBiological Chemistry vol 275 no 47 pp 37181ndash37186 2000

[92] L X Wu J H Xu K Z Zhang et al ldquoDisruption of theBcr-AblHsp90 protein complex a possible mechanism toinhibit Bcr-Abl-positive human leukemic blasts by novobiocinrdquoLeukemia vol 22 no 7 pp 1402ndash1409 2008

[93] C M Palermo J I Martin Hernando S D Dertinger AS Kende and T A Gasiewicz ldquoIdentification of potentialaryl hydrocarbon receptor antagonists in green teardquo ChemicalResearch in Toxicology vol 16 no 7 pp 865ndash872 2003

[94] C M Palermo C A Westlake and T A Gasiewicz ldquoEpi-gallocatechin gallate inhibits aryl hydrocarbon receptor genetranscription through an indirectmechanism involving bindingto a 90 kDa heat shock proteinrdquo Biochemistry vol 44 no 13 pp5041ndash5052 2005

[95] J H Jung M Yun E Choo et al ldquoA derivative of epigal-locatechin-3-gallate induces apoptosis via SHP-1-mediated sup-pression of BCR-ABL and STAT3 signalling in chronicmyeloge-nous leukaemiardquo British Journal of Pharmacology vol 172 no14 pp 3565ndash3578 2015

[96] B Goker C Caliskan H O Caglar et al ldquoSynergistic effect ofponatinib and epigallocatechin-3-gallate induces apoptosis inchronic myeloid leukemia cells through altering expressions ofcell cycle regulatory genesrdquo Journal of BUON vol 19 no 4 pp992ndash998 2014

[97] M C Wani H L Taylor M E Wall P Coggon and A TMcPhail ldquoPlant antitumor agents VI The isolation and struc-ture of taxol a novel antileukemic and antitumor agent fromTaxus brevifoliardquo Journal of the American Chemical Society vol93 no 9 pp 2325ndash2327 1971

[98] P B Schiff and S B Horwitz ldquoTaxol stabilizes microtubules inmouse fibroblast cellsrdquo Proceedings of the National Academy ofSciences of the United States of America vol 77 no 3 pp 1561ndash1565 1980

[99] D B Solit A D Basso A B Olshen H I Scher and N RosenldquoInhibition of heat shock protein 90 function down-regulatesAkt kinase and sensitizes tumors to TaxolrdquoCancer Research vol63 no 9 pp 2139ndash2144 2003

[100] A Sawai S Chandarlapaty H Greulich et al ldquoInhibition ofHsp90 down-regulates mutant epidermal growth factor recep-tor (EGFR) expression and sensitizes EGFR mutant tumors topaclitaxelrdquo Cancer Research vol 68 no 2 pp 589ndash596 2008

[101] O Bucur A L Stancu I Goganau et al ldquoCombination ofbortezomib andmitotic inhibitors down-modulate Bcr-Abl andefficiently eliminates tyrosine-kinase inhibitor sensitive and

resistant Bcr-Abl-positive leukemic cellsrdquo PLoS ONE vol 8 no10 Article ID e77390 2013

[102] J Davenport J R Manjarrez L Peterson B Krumm B SJ Blagg and R L Matts ldquoGambogic acid a natural productinhibitor of Hsp90rdquo Journal of Natural Products vol 74 no 5pp 1085ndash1092 2011

[103] L Zhang Y Yi J Chen et al ldquoGambogic acid inhibits Hsp90and deregulates TNF-120572NF-120581B in HeLa cellsrdquo Biochemical andBiophysical Research Communications vol 403 no 3-4 pp282ndash287 2010

[104] X Shi X Chen X Li et al ldquoGambogic acid induces apoptosis inimatinib-resistant chronic myeloid leukemia cells via inducingproteasome inhibition and caspase-dependent Bcr-Abl down-regulationrdquo Clinical Cancer Research vol 20 no 1 pp 151ndash1632014

[105] A Salminen M Lehtonen T Paimela and K KaarnirantaldquoCelastrol molecular targets of Thunder God Vinerdquo Biochem-ical and Biophysical Research Communications vol 394 no 3pp 439ndash442 2010

[106] T Zhang A Hamza X Cao et al ldquoA novel Hsp90 inhibitor todisrupt Hsp90Cdc37 complex against pancreatic cancer cellsrdquoMolecular Cancer Therapeutics vol 7 no 1 pp 162ndash170 2008

[107] H Hieronymus J Lamb K N Ross et al ldquoGene expressionsignature-based chemical genomic prediction identifies a novelclass of HSP90 pathway modulatorsrdquo Cancer Cell vol 10 no 4pp 321ndash330 2006

[108] Z Lu Y Jin L Qiu Y Lai and J Pan ldquoCelastrol a novel HSP90inhibitor depletes Bcr-Abl and induces apoptosis in imatinib-resistant chronic myelogenous leukemia cells harboring T315Imutationrdquo Cancer Letters vol 290 no 2 pp 182ndash191 2010

[109] Y Guo Y Li Q Shan G He J Lin and Y Gong ldquoCurcuminpotentiates the anti-leukemia effects of imatinib by downregula-tion of the AKTmTOR pathway and BCRABL gene expressionin Ph+ acute lymphoblastic leukemiardquoThe International Journalof Biochemistry amp Cell Biology vol 65 pp 1ndash11 2015

[110] C Giommarelli V Zuco E Favini et al ldquoThe enhancement ofantiproliferative and proapoptotic activity of HDAC inhibitorsby curcumin is mediated by Hsp90 inhibitionrdquo Cellular andMolecular Life Sciences vol 67 no 6 pp 995ndash1004 2010

[111] L-X Wu Y Wu R-J Chen et al ldquoCurcumin derivative C817inhibits proliferation of imatinib-resistant chronic myeloidleukemia cells with wild-type or mutant Bcr-Abl in vitrordquo ActaPharmacologica Sinica vol 35 no 3 pp 401ndash409 2014

[112] M Rai P S Jogee G Agarkar and C A Santos ldquoAnticanceractivities ofWithania somnifera current research formulationsand future perspectivesrdquo Pharmaceutical Biology pp 1ndash9 2015

[113] M Narayan J Zhang K Braswell et al ldquoWithaferin A regulatesLRRK2 levels by interfering with the Hsp90-Cdc37 chaperonecomplexrdquoCurrent Aging Science vol 8 no 3 pp 259ndash265 2015

[114] M K McKenna B W Gachuki S S Alhakeem et al ldquoAnti-cancer activity of withaferin A in B-cell lymphomardquo CancerBiology ampTherapy vol 16 no 7 pp 1088ndash1098 2015

[115] W Suttana SMankhetkornW Poompimon et al ldquoDifferentialchemosensitization of P-glycoprotein overexpressing K562Adrcells by withaferin A and Siamois polyphenolsrdquo MolecularCancer vol 9 article 99 2010

[116] K-J Huang Y-C ChenM El-Shazly et al ldquo5-Episinuleptolideacetate a norcembranoidal diterpene from the formosan softcoral Sinularia sp induces leukemia cell apoptosis throughHsp90 inhibitionrdquoMolecules vol 18 no 3 pp 2924ndash2933 2013


[117] W Aherne A Maloney C Prodromou et al ldquoAssays for Hsp90and inhibitorsrdquo in Novel Anti Cancer Drug Protocols vol 85 ofMethods In Molecular Medicine pp 149ndash161 Springer BerlinGermany 2003

[118] A A Baykov O A Evtushenko and S M Avaeva ldquoAmalachitegreen procedure for orthophosphate determination and its usein alkaline phosphatase based enzyme immunoassayrdquo Analyti-cal Biochemistry vol 171 no 2 pp 266ndash270 1988

[119] P A Lanzetta L J Alvarez P S Reinach and O A Candia ldquoAnimproved assay for nanomole amounts of inorganic phosphaterdquoAnalytical Biochemistry vol 100 no 1 pp 95ndash97 1979

[120] S J Gould and S Subramani ldquoFirefly luciferase as a tool inmolecular and cell biologyrdquoAnalytical Biochemistry vol 175 no1 pp 5ndash13 1988

[121] J Davenport M Balch L Galam et al ldquoHigh-throughputscreen of natural product libraries for Hsp90 inhibitorsrdquo Biol-ogy vol 3 no 1 pp 101ndash138 2014

[122] httpsclinicaltrialsgovct2resultsterm=NCT00100997ampcond=22Chronic+Myeloid+Leukemia22

[123] httpsclinicaltrialsgovct2showNCT00964873term=NCT00964873amprank=1


Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


MEDIATORSINFLAMMATION

of


Behavioural Neurology

EndocrinologyInternational Journal of



Disease Markers


BioMed Research International

OncologyJournal of



Oxidative Medicine and Cellular Longevity


PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of



Computational and Mathematical Methods in Medicine

OphthalmologyJournal of


Diabetes ResearchJournal of



Research and TreatmentAIDS


Gastroenterology Research and Practice


Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


BCR-ABL

CRKSO

SGRB-2CBL CRKL

GAB2 PI3-K

PIP3

AKT

IKKMDM2

p53

p27 STAT5BADERK12

RAS

RAF

MEK12

P P

P PP P

P

P

P

Cytoskeletalproteins

Altered adhesion motility

(a)(b)

(c)

(d)

Survival

Proliferation

P

NF120581B

IKB120572 Bcl-xL

Figure 1 Signaling pathways activated by BCR-ABL (a) BCR-ABL activates GRB-2SOS which in turn activates RAS Active RASactivates RAF Active RAF stimulates MEK1 which in turn activatesERK12 Activation of Ras pathway by BCR-ABL aids CML cellsproliferation On the other hand activated GRB-2SOS stimulatesGAB2 which activates PI3-K pathway (b) BCR-ABL phosphorylatesadaptor proteins like CRK and CRKL leading to the activation ofPI3-K PI3-K phosphorylates PIP2 to PIP3 which in turn activatesAKT AKT inhibits p27 leading to CML cells proliferation AKTphosphorylates MDM2 which in turn inhibit p53 AKT activatesNF120581B via phosphorylation of IKK and IkB120572 AKT inhibits p-BAD Activation of NF120581B and inhibition of p53 and BAD by AKTevade apoptosis and promote CML cells survival (c) BCR-ABLphosphorylates STAT5 which also aid in evading apoptosis of CMLcells (d) BCR-ABL phosphorylate cytoskeleton proteins resultingin increased cellular motility and reduced adhesion to extracellularmatrix of bone marrow

[8] Later in 1970 allogeneic stem cell transplantation inwhich patient receives stem cells from a genetically similardonor was used as an effective therapy for CML But thisapproach was risky due to limited availability of geneticallyidentical persons and caused death in elderly people [17] In1980 interferon-120572 (IFN-120572) proved effective for the treatmentof CML Such treatment prolonged the survival comparedto BUS and HU [18] Later the discovery of tyrosine kinaseinhibitors (TKIs) renewed theCML treatment (Figure 2)withincreased survival rates decreased side effects and improvedlife quality (Table 1)

31 First-Generation TKI Imatinib a 2-phenylaminopyrimi-dine derivative (Figure 2) competes with the ATP binding

site of c-ABL kinase of fusion BCR-ABL found in CML cells[19] Phase-I trials of imatinib showed significant antiprolif-erative activity in CML patients in which IFN-120572 treatmentfailed [20] In addition to ABL imatinib inhibits PDGFRArg and c-Kit except Src kinases Results of InternationalRandomized Study of Interferon and STI571 (IRIS) trialsshowed reliability and supremacy of imatinib related to IFN-120572 in terms of hematologic and cytogenetic responses [21]Imatinib was legalized by the US Food and Drug Admin-istration (FDA) in 2001

32 Resistance of Imatinib Resistance of imatinib is of twotypes BCR-ABL dependent and BCR-ABL independent Theformer is due to mutations in the BCR-ABL kinase domain[22] and overexpression of BCR-ABL protein [23] Pointmutations in the BCR-ABL kinase domain decrease or inhibitthe interaction of TKI with the aberrant BCR-ABLThe mostprevalently observed mutation in CML patients resistant toimatinib is T315I This mutation has isoleucine instead ofthreonine at the 315th amino acid in the BCR-ABL proteinAlterations in critical contact points due to amino acidsubstitutions increase the failure of TKI affinity to the targetsite Amino acid substitutions at 7 residues result inmutationssuch as G250E M244V M351T E255KV F359V Y253FHand T315I To date over 90 point substitution mutations inBCR-ABL kinase domain have been distinguished in drugresistant CML patients There are 4 regions that are essentialfor high frequency binding of imatinib (P-loop SH-3 SH-2and A-loop)The P-loop is responsible for phosphate bindingand mutations in this site were frequently observed in 43of patients who were generally in the acute and blast crisisphases The P-loop mutations E255K and Y253F increase theprobability of transformation depending on BCR-ABL kinaseactivity [24]

BCR-ABL independent resistance is due to LysM-con-taining receptor-like kinase (Lyn kinase) overexpression [25]and activation [26] increased levels of imatinib efflux trans-porters [eg ATP-binding cassette sub-family B multidrugresistance (MDR)] [27] and the multidrug resistant protein 1(MDA-1) [28]

33 Second Generation TKIs To overcome intolerance andimatinib resistance in CML patients development of second-generation TKIs such as dasatinib bosutinib and nilotinibwas unfolded [29] Various clinical studies like Dasatinibversus Imatinib Study in Treatment of Naive CML-ChronicPhase-Patients (DASISION) [30] Evaluating Nilotinib Effi-cacy and Safety in Clinical Trials-Newly Diagnosed Patients(ENESTnd) [31] and Bosutinib Efficacy and Safety in NewlyDiagnosed CML (BELA) [32] trials showed efficacy andsuperiority of second-generation TKIs over first-generationTKI [33]

Dasatinib a thiazolecarboxamide (Figure 2) binds to theBCR-ABLrsquos ATP binding site with more compatibility thanimatinib [34] Dasatinib is capable of binding to both theopen and closed conformations of BCR-ABL whereas ima-tinib binds only to the closed conformation of the BCR-ABL[35] Dasatinib was affirmed by the US FDA in 2007 [36]










Third-generationTKI



O

N

N

NN

HH

N

N

N

(a) Imatinib

Me

Me

N

N

N

HO

N N

N NHH

OCl

S

(b) Dasatinib

N NN

HN

NHO

FF

F

NN

(c) Nilotinib

∙H2O

OMe

MeO

ON

NMe

ClCl

HN

CN

N

(d) Bosutinib

OFF

F

N

NN

NH

N

N

(e) Ponatinib

















6 Hsp90 and Cancer




Hsp90


ErbB-2 Akt Src MEK)



(n-TERT telomerase)


Myt-1 Cyclin-D)


(c-MET MMP2)




(EGFR Raf BCR-ABL

(Plk-1 Cdk4 Cdk6



7 Hsp90 and CML







50is 20ndash




BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP


M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL


ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)













Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

























Third-generationTKI



O

N

N

NN

HH

N

N

N

(a) Imatinib

Me

Me

N

N

N

HO

N N

N NHH

OCl

S

(b) Dasatinib

N NN

HN

NHO

FF

F

NN

(c) Nilotinib

∙H2O

OMe

MeO

ON

NMe

ClCl

HN

CN

N

(d) Bosutinib

OFF

F

N

NN

NH

N

N

(e) Ponatinib

















6 Hsp90 and Cancer




Hsp90


ErbB-2 Akt Src MEK)



(n-TERT telomerase)


Myt-1 Cyclin-D)


(c-MET MMP2)




(EGFR Raf BCR-ABL

(Plk-1 Cdk4 Cdk6



7 Hsp90 and CML







50is 20ndash




BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP


M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL


ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)













Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of































6 Hsp90 and Cancer




Hsp90


ErbB-2 Akt Src MEK)



(n-TERT telomerase)


Myt-1 Cyclin-D)


(c-MET MMP2)




(EGFR Raf BCR-ABL

(Plk-1 Cdk4 Cdk6



7 Hsp90 and CML







50is 20ndash




BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP


M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL


ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)













Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















Hsp90


ErbB-2 Akt Src MEK)



(n-TERT telomerase)


Myt-1 Cyclin-D)


(c-MET MMP2)




(EGFR Raf BCR-ABL

(Plk-1 Cdk4 Cdk6



7 Hsp90 and CML







50is 20ndash




BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP


M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL


ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)













Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















BCR-ABL

C

M

N

C

Hsp90 dimer

C

N

C

NN

P P

ATP

ADP


M

N

MM BCR-ABL

(a)

BCR-ABL

C C

BCR-ABL


ABL

Hsp90 inhibitors

Hsp90 dimer

MM

N N

(b)













Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of




















Hsp90


References


domain of Hsp90


[74]





ABL[90]



ABL

[91 92]





[101]



ABL

[103 104]


to Hsp90


[107 108]


Plant NYK


[110 111]



[114 115]



[116]






N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















N

O

O

OO

O

OH

H

CH3O

CH3O

CH3O

NH2

(a) Geldanamycin

O

O

O

O

H

H

H

N

N

CH3

CH3

H3CO

H3COH3C

H3C

OCONH2

H2C

(b) 17-AAG

O

O

OOH

O

O

O

O

HN

N

N

CH3

CH3

CH3

CH3

H3C

H3C

H3C

H3C

H

NH2

(c) 17-DMAG

O

N

N

NHN OH

OH

(d) Ganetespib

O

O

O HN

H3CO

H3CO

H3C

OCONH2

CH3 CH3

CH3

CH3OOCH3

(e) Herbimycin A

O

O

OO

OO

O

OHN

H2N

(f) MacbecinO

OO

OOH

HO HH

Cl

(g) Radicicol

O

OO

HO

OH

OH

Cl

CH2

N

(h) KF25706

O

OH

Me

Me

MeMe

MeO

ONa

Me

HN

OOO

O

O

O

OH

H2N

(i) Novobiocin



HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















HO

OHO

O

O

OH

OH

OH

OH

OH

OH

(a) EGCG

OH

OH

NHO

O

O

H

O

OO

OO

O

OO

HO

(b) Taxol

O

O

O

O

O

O

H

H

OH

OH(c) Gambogic acid

O

HO

OH

O

H

H3C

H3C

H3C CH3

CH3

CH3

(d) Celastrol

HO

O O

OH

OCH3CH3O

(e) Curcumin

O

O

O

OOH

OH

H3C

H3C

CH3

CH3

(f) Withaferin A







O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















O

O2

1 15

16

17

14

18

1312

19

11109

87 6

54

3

O

O

O

RH

H

H

OH

1 R = H 2 R = OH















10 Conclusions



ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















ADP

ATP

PEP

Pyruvate

Pyruvatekinase

LDH

Lactate

Hsp90

NAD+NADH + H+

(a)


Refolded luciferase


Hsp90 inhibitors

Hsp90

Hsp90

Luciferyladenylate

PPi

Oxyluciferin AMPO2

(b)




Abbreviations
















References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of


























References










































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






























































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






























of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of





















of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















Documents

Review Article Hsp90 Inhibitors for the Treatment of