Review Article A New Aurora in Anaplastic Thyroid Cancer ...downloads.hindawi.com/journals/ije/2014/816430.pdf · A New Aurora in Anaplastic Thyroid Cancer Therapy EnkeBaldini,MassiminoD

Review ArticleA New Aurora in Anaplastic Thyroid Cancer Therapy

Enke Baldini Massimino DrsquoArmiento and Salvatore Ulisse

Department of Experimental Medicine ldquoSapienzardquo University of Rome Viale Regina Elena 324 00161 Rome Italy

Correspondence should be addressed to Salvatore Ulisse salvatoreulisseuniroma1it

Received 15 April 2014 Accepted 11 June 2014 Published 1 July 2014

Academic Editor Giuliana Salvatore

Copyright copy 2014 Enke Baldini et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Anaplastic thyroid cancers (ATC) are among the most aggressive human neoplasms with a dire prognosis and a median survivaltime of few months from the diagnosis The complete absence of effective therapies for ATC renders the identification of noveltherapeutic approaches sorely needed Chromosomal instability a feature of all human cancers is thought to represent a majordriving force in thyroid cancer progression and a number of mitotic kinases showing a deregulated expression inmalignant thyroidtissues are now held responsible for thyroid tumor aneuploidy These include the three members of the Aurora family (Aurora-AAurora-B and Aurora-C) serinethreonine kinases that regulate multiple aspects of chromosome segregation and cytokinesisOver the last few years several small molecule inhibitors targeting Aurora kinases were developed which showed promisingantitumor effects against a variety of human cancers including ATC in preclinical studies Several of these molecules are nowbeing evaluated in phase III clinical trials against advanced solid and hematological malignancies In the present review we willdescribe the structure expression and mitotic functions of the Aurora kinases their implications in human cancer progressionwith particular regard to ATC and the effects of their functional inhibition on malignant cell proliferation

1 Aurora Kinases From Genes to Proteins

The Aurora kinases belong to a family of serinethreoninekinases having in the Ipl1p (increase in ploidy 1) gene sub-sequently named Aurora gene the founding member discov-ered in the budding yeast Saccharomyces cerevisiae during agenetic screening for mutations causing defective chromo-somal segregation [1] In yeast the Ipl1 remains the onlyAurora kinase so far identified while twoAurora kinases havebeen found in Drosophila melanogaster and in Caenorhab-ditis elegans [2ndash4] In mammals three Aurora kinases havebeen identified and characterized Aurora-A Aurora-B andAurora-C [5] The catalytic domains of these three proteinsare highly related in sequence showing 67ndash76 identitybut their N-terminal domains have little similarity which isheld responsible for their distinct intracellular localizationssubstrate specificity and functions (Figure 1) In addition theamino acid sequence of the catalytic domains of Aurora-AAurora-B and Aurora-C is highly conserved across differentorganisms suggesting its relevance for protein functions andregulation mechanisms across species [5] The expression ofall three human Aurora kinases is cell cycle regulated beinglow in the G1S phase andmaximal in the G2M phase In the

next three paragraphs we will briefly summarize our knowl-edge regarding the characteristics of the Aurorasrsquo encodinggenes their promoter regulation and protein structure

11 Aurora-A TheAurora-A is encoded by the AURKA gene(also known as AIK AuroraIPL1-like kinase ARK1 Aurorarelated kinase 1 AURA AURORA2 BTAK breast tumor-amplified kinase PPP1R47 protein phosphatase 1 regulatorysubunit 47 STK15 serinethreonine-protein kinase 15 STK6serinethreonine kinase 6) located at 20q132 and consistingof 11 exons (Gene ID 6790)

The AURKA promoter contains a putative TATA-box atminus37 to minus14 and two CCAAT-boxes at minus101 to minus88 and at minus69tominus56 (Eukaryotic PromoterDatabase Swiss Institute of Bio-informatics) Tanaka and colleagues analyzed the 18 kb 51015840-flanking region of the Aurora-A gene and found two distinctcis-regulatory elements one positively regulates transcriptionof the Aurora-A gene while the other is a cell cycle dependenttranscriptional repressor [6]The former is the 7 bp sequenceCTTCCGG located at minus85 to minus79 and essential for the trans-cription of the Aurora-A gene which is bound by the E4TF1a ubiquitously expressed ETS family protein The cell cycle

Hindawi Publishing CorporationInternational Journal of EndocrinologyVolume 2014 Article ID 816430 11 pageshttpdxdoiorg1011552014816430

2 International Journal of Endocrinology

COOH1 76 251 345

COOH1 8 249 309

COOH1 133 383 403

Activation loop D-boxA-boxDAD

KEN motif

Aurora-A

Aurora-B

Aurora-C

Catalytic domain

NH2

NH2

NH2

Figure 1 Schematic representation of Aurora kinase proteins D-box destruction box DAD D-box activating domain KEN motifamino acidic K-E-N which serves as targeting signal for the Cdh1-anaphase promoting complex

dependent transcriptional repressor is formed by tandemrepression elements consisting of a cell cycle dependent ele-ment (CDE) located at minus44 to minus40 (CGCCC) and a cell cyclegene homology region (CHR) located atminus39 tominus35 (TTAAA)[6] It is worth mentioning that in addition to Aurora-A the G2M specific transcription of different genes suchas cyclin A cdc25C cdc2 polo-like kinase and others isregulated by similar tandem repression elements [6ndash9] Overthe last few years a number of transcription factors capable ofmodulating the expression of AURKA gene have been identi-fied These include the p53 the HIF-1 and the INI1hSSNF5all reported to negatively regulate the activity of the AURKApromoter [10ndash12] Conversely the transcriptional activity ofthe AURKA promoter has been shown to increase followingthe interaction with the ΔEGFRSTAT5 complex in glioblas-toma cells [13] Moreover the oncogeneMYCN a member ofthe MYC family of basic helix-loop-helix transcription fac-tors has been described to bind the AURKA promoter eitheralone or in complex with the DNA methyl binding proteinMeCP2 in the neuroblastoma derived cell line Kelly [14]EWS-Fli1 a fusion gene resulting from the chromosomaltranslocation (11 22 q24 q12) encodes a transcriptional acti-vator capable of promoting cellular transformation in Ewingsarcoma cells Experimental evidence showed that EWS-Fli1protein upregulates Aurora-A and Aurora-B expression bybinding to regulatory ETS-binding sites located at minus84 andminus71 bp upstream of the transcription initiation sites in bothAurora-A and Aurora-B promoters [15] Similarly it has beensuggested that activation of the MAPK in pancreatic cancercells leads to the transcriptional activation of the AURKA andAURKB promoters via ETS2 transcription factors [16]

The 24 kb transcript from AURKA gene encodes aprotein of 403 amino acids with a predicted molecular massof 458 kDa (Figure 1) Like all Aurora proteins it is char-acterized by a C-terminal catalytic domain containing theactivation loop In the latter anAurora kinase signature (xRx-TxCGTx) is present in which the autophosphorylation of theThr288 is required for kinase activation [17] In addition theThr288 is positionedwithin a protein kinaseA (PKA) consen-sus sequence and in vitro experiments indicated a potential

role of PKA in Aurora-A phosphorylation [18 19] The phos-phatase PP1 has been shown to dephosphorylate and inacti-vate Aurora-A [19] The C-terminal located destruction box(D-box) containing the motif RxxLxxG and the N-terminalA-boxD-box activating domain (DAD) containing themotifRxLxPS play an essential role in Aurora-A degradation bythe anaphase promoting complexcyclosome- (APCC-)ubiquitin-proteasomepathwayAurora-Adegradation occursin late mitosisearly G1 phase when the D-box is targeted byFizzy related proteins that transiently interact with the APCand is hCdh1 dependent [18ndash21] In theN-terminal region theamino acidic sequence K-E-N known as KEN motif is alsopresent which serves as targeting signal for Cdh1-APCrequired also for the degradation of other mitotic proteinssuch as Nek2 and B99 [22] However this does not seem tobe crucial for Aurora-A degradation [22]

12 Aurora-B The Aurora-B is encoded by the AURKB gene(also known as AIK2 AIM1 ARK2 AurB IPL1 STK5 AIM-1 STK12) mapped to chromosome 17p131 and consisting of9 exons (Gene ID 9212)

The AURKB promoter contains three putative CAAT-boxes at minus99 to minus86 at minus66 to minus53 and at minus30 to minus17 (Eukary-otic PromoterDatabase Swiss Institute of Bioinformatics) Byprimer extension twomajor transcription initiation sites wereidentified [23] As for the Aurora-A promoter also theAurora-B promoter possesses the CDE and CHR elementsthough responsible for the cell cycle regulation of its expres-sion and several CDE-binding proteins have been identifiedby means of electrophoretic mobility shift assay and biotin-streptavidin pull-down assay including the E2F-1 E2F-4 andDP-2 [23] As above described the AURKB promoter maybe positively regulated by transcription factors such as theETS2 via ETS-binding sites present in the promoter sequence[15 16]

The 14 kb transcript encodes a protein of 345 aminoacids with a predicted molecular mass of 39 kDa (Figure 1)[5] As described for Aurora-A also the Aurora-B protein ischaracterized by a catalytic domain a C-terminal D-box andan N-terminal A-boxDAD [18ndash21] However althoughAurora-B possesses the same D-box as Aurora-A it is notdegraded by the same ubiquitin ligase but undergoes degra-dation following its binding to the human proteasome 120572-subunit C8 in a proteasome dependent manner [24]

13 Aurora-C TheAurora-C is encoded by the AURKC gene(also known as AIE2 AIK3 ARK3 AurC SPGF5 STK13)which localizes at chromosome 19q1343 and consists of 7exons (Gene ID 6795)

The AURKC promoter contains a CCAAT-box at minus36 tominus23 (Eukaryotic Promoter Database Swiss Institute of Bioin-formatics) Expression of AURKC is downregulated by PLZFa transcriptional repressor through recruitment to its pro-moter region and it is of interest to note that the expressionlevels of PLZF andAURKCmRNAs display opposite patternsin human cervical and colorectal cancers [25]

The 13 kb transcript encodes a protein of 309 aminoacids with a predicted molecular mass of 356 kDa (Figure 1)

International Journal of Endocrinology 3

[5] As the other members of the family also Aurora-C ischaracterized by a catalytic domain present in the C-terminalregion of the molecule (Figure 1) However differently fromAurora-A andAurora-B Aurora-C does not contain the KENand the A-boxDAD motifs in its N-terminal region whilethe C-terminal D-box is present The mechanism(s) under-lying its degradation however still remains to be elucidatedand represents an interesting area of investigation

2 Expression Subcellular Localization andFunctions of the Aurora Kinases

The three Aurora kinases play relevant functions during themitotic phase of the cell cycle [18 19] As mentioned theseproteins display distinct intracellular localizations substratespecificity and functions during mitosis and their expres-sion and activity are tightly regulated at the transcrip-tional or posttranscriptional level through phosphoryla-tiondephosphorylation and protein degradation [26] In thenext paragraphs we will briefly discuss the main mitoticfunctions of the Aurora kinases and we will mention recentreports suggesting their extramitotic functions

21 Aurora-A The expression of Aurora-A is cell cycle regu-lated being very lowduring theG1 phase and starting to accu-mulate at the centrosome in the late S phase to be maximal atthe G2-M transition Duringmitosis it localizes at the spindlepoles to be inactivated and degraded before cytokinesis asabove mentioned [19 22] Aurora-A regulates centrosomeseparation and maturation cell mitotic entry and bipolarspindle construction Centrosome recruitment of Aurora-Ais controlled by the Cep192Spd-2 (centrosome protein of192 kDaspindle defective 2) which is also involved in kinaseactivation during mitosis [27] Once on the centrosomeAurora-A promotes the recruitment to the pericentriolarmass (PCM) of a number of proteins required for propercentrosome maturation and function These include centro-somin 120574-tubulin LATS2 (large tumor suppressor homolog2) TACC3 (transforming acidic coiled coil 3) and NDEL1(nuclear distribution element-like 1) [19 22 28]

While promoting centrosomematuration Aurora-A acti-vates the CDK1cyclin B complex allowing the transition ofthe cell from the G2 to the M phase [29ndash31] In particularAurora-A in association with the G2 induced Bora proteinphosphorylates the PLK1 (polo-like kinase 1) Both Aurora-Aand PLK1 phosphorylate CDC25B (cell division cycle 25 B)a member of the CDC25 family of phosphatases which acti-vates cyclin dependent kinases by removing two phosphategroups leading to CDK1Cyclin B complex activation andfinally promoting mitotic entry [19 29ndash31] PLK1 facilitatesthis process also by inactivating the CDK1 inhibitor WEE1(Figure 2) Inactivation of Aurora-A or Plk1 individuallyshows no significant effect on Cdk1 activation and entry tomitosis while their simultaneous inactivation produces amarked delay in both Cdk1 activation and mitotic entry sug-gesting that the two kinases have redundant functions [32]

A central role of Aurora-A during mitosis is to supportthe microtubule-organizer center (MTOC) responsible for

the formation of the bipolar spindle In this context Aurora-Ahas been shown to form complexes with TACC1 and TACC3which in turn by binding to ch-TOGXMAP215 proteinsstabilizemicrotubules at the centrosome [33ndash35] In additionAurora-A interacts with and phosphorylates TPX2 which iscapable of promoting spindle microtubule polymerization[22]

22 Aurora-B Aurora-B mRNA and protein levels peak atG2M phase and the maximum kinase activity is reachedfrommetaphase to the end ofmitosis [18 19] Aurora-B exertsits action mainly in concert with three other proteins that isINCENP (inner centromere protein) survivin and bore-alinDasra B with which it associates in the chromosomalpassenger complex (CPC) In early prophase the CPC islocated on chromosomal condensing arms where it seems todisplace the heterochromatin protein-1 from DNA and torecruit condensin proteins (Figure 3) [36 37] From early G2phase to prophase Aurora-B phosphorylates histone H3 butits physiological meaning remains unclear From late pro-phase to metaphase CPC localizes to the inner centromereplaying a role in formation and stability of the bipolar mitoticspindle kinetochore assembly correction of nonbipolarchromosome-spindle attachments and control of the spindlecheckpoint (Figure 3) At the beginning of anaphase CPCrelocates to the midzone of the mitotic spindle and to the cellcortex remaining evident in the midbody of telophasic cellswhere it modulates the activity of several proteins involvedin spindle dynamics cleavage furrow formation and comple-tion of cytokinesis (Figure 3) [18 19 36 37]

Aurora-B activation requires its autophosphorylationand binding to INCENP while all CPC components arenecessary for its proper localization during mitosis Severalkinases such as BubR1 and Bub1 (checkpoint kinases) Mps1(monopolar spindle 1) Chkl (checkpoint kinase 1) tousled-like kinase-1 Plk1 and TD-60RCC2 (regulator of chro-mosome condensation 2) have been recently shown to beinvolved in Aurora-B activation TD-60 a protein with achromosomal passenger-like localization pattern seems to bealso important for centromeric localization of Aurora-B [38]The phosphorylation status and activity of Aurora-B aremodulated by PP1 and PP2A phosphatases depending on theregulatory subunit they are bound to these enzymes candirectly modulate Aurora-B activity through dephosphoryla-tion or they may dephosphorylate Aurora-B substrates [38]

23 Aurora-C Expression of Aurora-C is maximal duringthe G2M phase The observation that Aurora-C is expressedat relative high levels in germ cells during spermatogenesisand oogenesis and at very low levels in somatic cells is of inter-est Aurora-C is highly similar to Aurora-B in sequence (61identity) whichmay explainwhy the two kinases display sim-ilar localization patterns and share interacting proteins andsubstrates such as INCENP survivin and borealin [18 39]Interestingly when ectopically expressed in cells depleted ofAurora-B Aurora-C is capable of rescuing the Aurora-B-dependent mitotic functions [40] It is also worth noting thatAurora-C has been shown to interact with and phosphorylate


Aurora-A

PLK1

Bora Wee1

CDC25Cyclin B

Cdk1

Cyclin B

Cdk1

Mitotic entry

Centrosome

(a)

120573-Tubulin Aurora-A DAPI Merge

(b)

Figure 2 (a) Schematic representation of the pathway induced by Aurora-A to activate the CDK1cyclin B complex allowing the transitionof the cell from the G2 to the M phase Aurora-A in association with Bora phosphorylates the PLK1 Both Aurora-A and PLK1 phosphorylateCDC25B (cell division cycle 25 B) allowing cyclin dependent kinase 1(CDK1)cyclin B complex activation and thus promoting mitotic entryPLK1 facilitates this process also by inhibiting the CDK1 inhibitor WEE1 Inactivation of Aurora-A or Plk1 individually shows no significanteffect on Cdk1 activation and entry to mitosis while their simultaneous inactivation produces a marked delay in both Cdk1 activation andmitotic entry suggesting that the twokinases have redundant functions (b) Immunofluorescence showingAurora-A localization at the spindlepole of an anaplastic thyroid cancer cell in metaphase

TACC1 in thyroid cells [40] In the latter TACC1 and Aurora-C have been shown to colocalize in the cytokinetic bridge[41]

24 Extramitotic Functions of Aurora Kinases Over the lastfew years different experimental findings suggest extrami-totic functions for Aurora-A and Aurora-C In particularAurora-A has been proposed to affect microtubule dynamicscell migration and polarity cilia disassembly and regulationof intracellular calcium signaling in interphasic cells [22]Regarding Aurora-C it has been shown that along with itsinteracting protein TACC1 it may be involved in telomere

stability In particular TACC1 has been shown to bind theLSM7 and SmG proteins involved in telomere formationwhile the TFR2 protein a component of the telomericcomplex shelterin has been shown to form a complex withAurora-C [42 43] Thus it may be speculated that TACC1andor Aurora-C may contribute to telomere homeostasis

3 Aurora Kinases and Cancer

Genetic instability a hallmark of solid tumors is thought torepresent themean bywhich premalignant cells acquire novelfunctional capabilities responsible for cancer cell growth and


Aurora-B

Prophase Metaphase Anaphase Cytokinesis

(a)

Aurora-B

Tubulin

Aurora-BAurora-BAurora-B Spindle

(b)

Figure 3 Schematic representation (a) and immunofluorescence images (b) of Aurora-B localization during mitosis in an anaplastic thyroidcancer cell In (b) Aurora-B is in green microtubules are in red and DNA stained by DAPI is in blue

tumour progression [44] In fact aberrations in chromosomenumber and structure characterize the majority of humancancers and follow alterations of cellular functions requiredfor appropriate chromosome segregation and integrity ofcellular checkpoints [45] Given the crucial tasks of Aurorakinases in all mitotic stages their dysfunction andor dysreg-ulation may well lead to abnormal cell divisions and aneu-ploidyHowever whetherAurora kinases have a role in cancerinitiation is still a matter of debate It has been reported thatthe overexpression of either Aurora-A Aurora-B or Aurora-C induces cell malignant transformation [46ndash48] In differentstudies however although the ability of Aurora-A or Aurora-B to potentiate Ras-induced transformation was demon-strated the transforming ability of either Aurora-A orAurora-B overexpression alone was not observed [49 50]

Aurora-A kinase has been often implicated in cancerprogression and its hyperactivation has been demonstratedto induce resistance to microtubule-targeted chemotherapy[51ndash53] The AURKA gene is often amplified in many malig-nancies and its overexpression has been reported to be sig-nificantly associated with a higher tumor grade and a poorprognosis in a number of cancers such as chondrosar-coma nasopharyngeal carcinoma ER-positive breast cancerglioblastoma colorectal cancer gastric cancer and endo-metrioid ovarian carcinoma [54ndash60] In addition somaticmutations located within the catalytic domain of Aurora-Aaltering kinase activity and subcellular localization have beendescribed in human cancer cells [61]The oncogenic potentialof Aurora-A derives from a sum of several spatially andtemporally distinct actions Unlike normal cells in many

cancer cells the expression of Aurora-A becomes constitu-tive throughout the cytoplasm regardless of the cell cyclephase this can trigger a plethora of phosphorylated proteinsimproper interactions and mislocalization Aurora-A mayalso represent the downstream target of mitogenic pathwayssuch as MAPKERK (mitogen-activated protein kinases)and hence be overexpressed because of their constitutiveactivation in tumors [52]TheAurora-A excess interferes withdifferent cell cycle checkpoints that is the lateG2 checkpointwhich restrains genetically aberrant cells to enter mitosis thespindle assembly checkpoint which blocks the metaphase-anaphase transition in cells with defective spindles andthe postmitotic G1 checkpoint which arrests cell cyclein aneuploid cells [51 53] Centrosome amplification andunrestrained multinucleation leading to abnormal mitoticspindle are also observed in Aurora-A overexpressing cells[62] Moreover Aurora-A may significantly contribute totumor progression by interacting with and inhibiting severaltumor suppressor proteins such as p53 BRCA1 (breast cancer1) and Chfr (checkpoint with forkhead and ring fingerdomains)

Aurora-B plays a less clear role in tumorigenesis Anincreased level of Aurora-B in normal cells has been shownto induce premature chromosome separation and segregationerrors to promote generation of tetraploid and aneuploidcells which develop a transformed phenotype in vitro and invivo and as above mentioned to potentiate Ras oncogenicactivity [47 50 63ndash65] Neither amplification nor specificmutations of its gene have been shown in tumors never-theless Aurora-B overexpression has been demonstrated in


Table 1 Aurora kinase inhibitors in clinical trials

Inhibitor (company)commercial name Clinical trial

Pan-Aurora inhibitors

VX-680MK-0457 (VertexMerck)Tozasertib Phase II (terminated due to severe toxicity)

PHA-739358 (PfizerNerviano)Danusertib Phase II

PHA-680632 (PfizerNerviano) Phase IICYC-116 (Cyclacel) Phase ISNS-314 (Sunesis) Phase IR763 (Rigel) Phase IAMG-900 (Amgen) Phase IAT-9283 (Astex) Phase IIPF-03814375 (Pfizer) Phase IGSK1070916 (GlaxoSmithKline) Phase I

Aurora-A inhibitorsMLN8237 (Millennium) Phase IIEMD-2076 (EntreMed) Phase IIMK-5108 (Vertex) Phase I

Aurora-B inhibitors AZD1152 (AstraZeneca) Phase II

several cancer types like breast colorectal kidney lung andprostate cancer and it has been reported to correlate withthe level of genomic instability and with poor prognosisin advanced colorectal cancer astrocytoma head and necksquamous cell cancer and endometrial and hepatocellularcarcinomas [51 63ndash65] At present very little information isavailable about the role of Aurora-C in cancers DespiteAurora-C is hardly detected in normal somatic cells it ishighly expressed in various tumor cell lines [66ndash69] Onestudy has described the transforming potential of overex-pressedAurora-C inNIH-3T3 cells and a correlation betweenthe level of active kinase and tumor aggressiveness of the cellsinjected in nude mice [48]

The overexpression of Aurora kinases in human cancersand their relevance in controlling themitotic process have ledto the development of small-molecule inhibitors as putativeanticancer drugs Aurora inhibition results in cytokinesis fail-ure and generation of tetraploid cells which depending onthe postmitotic checkpoint activation may be unable to pro-ceed in cell cycle or rather proliferate and become polyploidThe exit from cell cycle is likely to generate viable quiescentcells whereas endoreplicating cells have greater tendency toundergo apoptosis Nowadays the Aurora kinase inhibitorsare considered a promising therapeutic option especiallyagainst those cancers that do not respond to currently avail-able anticancer therapies [70ndash77] About 30 small moleculeinhibitors of Aurora kinases are under preclinical and clinicalevaluation with some of them reported in Table 1 under-going phase I-II clinical trials for solid and hematologicalcancers [70ndash77] The responses obtained in these clinicaltrials showed either disease stabilization or less frequentlypartial responses in patients with solid cancers while morepromising activity has been observed in patients with hema-tological malignancies [70ndash77] However a number of sideeffects most of which reversible upon drug withdrawal were

observed [74] On-target toxicity encountered in the differ-ent clinical trials included grade 34 neutropenia leukope-nia and myelosuppression while off-target effects includedhypertension somnolence mucositis stomatitis proctalgiagrade 3 increase in aspartate aminotransferase and ventricu-lar dysfunction [70ndash77] Cardiotoxicity associatedwith deathof one patient has been recorded in a phase II clinical trialwith tozasertib (VX-680) [74]

4 Thyroid Cancers

Epithelial thyroid cancer (TC) accounts for about 1 of allhuman tumors and represents the most common endocrinemalignancy the fifth most common cancer in women in theUnited States [78 79] The majority of TC (90ndash95) is differ-entiated carcinomas (DTC) occurring as papillary (PTC) orfollicular (FTC) histotypes the incidence of which has beenincreasing over recent years [80] Following dedifferentiationDTC are assumed to generate the poorly DTC (PDTC) andthe highly aggressive and invariably fatal anaplastic thyroidcarcinomas (ATC) [81 82] Relevant molecular alterationsencountered in DTC progression comprise gene rearrange-ments of tyrosine kinase receptors such as the RETPTC andNTRK1 (neurotrophic receptor-tyrosine kinase 1) or activat-ing point mutations of proteins mediating cellular responsesto growth and differentiation signals including RAS BRAFphosphatidylinositol 3-kinase (PI3K) or the oncogenicfusion protein PAX8-PPAR120574 as well as inactivating muta-tions in the tumor suppressor phosphatase and tensin homo-log (PTEN) and TP53 [83ndash85] The conversion of early-stagethyroid tumors to more aggressive and invasive malignan-cies occurs through an epithelial-to-mesenchymal transition(EMT) which implies the loss of cell-cell contacts remod-eling of cytoskeleton and the acquisition of a migratory


phenotype [86 87] In fact abnormal expression of inte-grins Notch MET TGF120573 NF-120581B PI3K TWIST1 matrixmetalloproteinases (MMP) components of the urokinaseplasminogen activating system (uPAS) and p21-activatedkinase (Pak) involved in the EMT has been identified inPTC progression [86ndash91] Genomic instability a hallmark ofsolid tumors including TC is thought to represent the drivingforce responsible for the generation and accumulation in themalignant cells of the above-mentionedmolecular alterations[44 92ndash94] According to this hypothesis is the evidence thatthe number and the frequency of chromosomal abnormal-ities observed during thyroid cancer progression increasefrom the DTC to the PDTC and ATC [92ndash94]

While the prognosis for DTC patients is favorable with10-year survival rate of about 90 that for patients affectedby PDTC and ATC is very poor with a median survivalof only few months from diagnosis [94ndash96] It has to benoted in fact that the surgical resection of the tumor mass isnot effective in ATC patients and treatment of recurrent orpersistent PDTC and ATC with conventional radiotherapyandor chemotherapy provides little or no benefit Thereforenovel therapeutic approaches are sorely needed for theseneoplasms [85 97]

5 Aurora Kinases and Thyroid Cancers

Normal human thyrocytes express all three Aurora kinasesin a cell cycle dependent manner [67] The expression ofAurora-A andAurora-B in this cell type ismainly regulated atthe transcriptional level while that of Aurora-C appears to bemodulated at the posttranscriptional level [67] An increasedexpression of all three Aurora kinases has been shownin various cell lines originating from different epithelialthyroid tumor histotypes compared to normal thyrocytes aswell as in DTC and ATC tissues compared to normalmatched tissues [33 67 98] In addition a study aimed atevaluating the gene expression profile in ATC by means oftissue microarray and immunohistochemistry identifiedAURKAas one of themost frequently andmost strongly over-expressed genes in these tumors [99] This is consistent withthe observation that gain of chromosome 20q whereAURKAis located (20q132) is frequently encountered in ATC [100]Based on these findings the potential therapeutic value ofAurora kinase inhibition on the proliferation and growthof ATC cells has been evaluated in preclinical studies [101ndash105] In particular the in vitro effects of different pan-Aurorakinase inhibitors including theMK-0457 (VX-680) the SNS-314 mesylate and the ZM447439 have been investigated onproliferation apoptosis cell cycle ploidy and anchorage-independent growth of a panel ofATC-derived cell lines [102ndash104] These molecules were found to inhibit proliferation ofATC cells in a time- and dose-dependent manner and toimpair cancer cells colony formation in soft agar Cytofluo-rimetric analysis of cell cultures exposed to the pan-Aurorakinase inhibitors revealed an accumulation of tetra- andpolyploid cells because of endoreplication events followed bythe activation of caspase-3 and accumulation of a sub-G0G1 cell population both indicative of apoptosis [102ndash104]

Treated cells showed mitotic alterations consistent with theinhibition of Aurora kinases including major impairmentof centrosome functions with abnormal spindle formationcharacterized by the presence of short microtubules inhibi-tion of histoneH3 phosphorylation and inability to completethe cytokinesis In addition the selective inhibition of eitherAurora-A or Aurora-B has been investigated [101 105 106]The selective inhibition of Aurora-B expression by means ofRNA interference or of Aurora-B function by AZD1152 hasbeen reported to significantly reduce growth and tumori-genicity of ATC-derived cells both in vivo and in vitro [101]Similarly functional inhibition of Aurora-A byMLN8054 in apanel of ATC-derived cell lines has been shown to inhibit cellproliferation and to induce cell cycle arrest and cell apoptosis[105] In xenograft experiments the Aurora-A inhibitor wasfound to reduce tumor volume by 86 [105] Interestingly thecombined treatment with MLN8054 and bortezomib target-ing the ubiquitin-proteasome system showed additive effectson ATC-derived cell proliferation and apoptosis comparedto monotherapy [106] Pazopanib an inhibitor of kinasesincluding the VEGFR (vascular endothelial growth factorreceptor) shown to have impressive therapeutic activity inpatients affected by radioactive iodine-refractory DTC wastested in a phase II clinical trial on ATC patients [107 108]Despite several pazopanib treated ATC patients showed atransient disease regression no RECIST (response evaluationcriteria in solid tumors) response was obtained [106] Morerecently in a preclinical study on a panel of ATC derived celllines pazopanib was found to potentiate the cytotoxic effectsof paclitaxel in vitro and in xenograft experiments [109] Theeffects of this pazopanibwere attributed to an unexpected off-target inhibition of Aurora-A in ATC derived cell lines Infact the same results were obtained when combining pacli-taxel and MLN8237 a selective Aurora-A inhibitor In thesame study the authors also showed that the combinedadministration of pazopanib and paclitaxel attained amarkedand durable regression of lung metastasis in a single ATCpatient [109]

In conclusion the preclinical and clinical data so far avail-able indicate that Aurora kinase inhibitors may have a ther-apeutic potential for ATC treatment either in monotherapyormore likely in combination therapywith anti-microtubuledrug

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Enke Baldini Massimino DrsquoArmiento and Salvatore Ulissecontributed to writing the first draft and all of them con-tributed to the revisions and approved the final version of thepaper

Acknowledgment

This work was supported by the MIUR Grant PRIN20102011(Protocol no 2010BX2SNA 002)


References

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[2] D M Glover M H Leibowitz D A McLean and H ParryldquoMutations in aurora prevent centrosome separation leading tothe formation ofmonopolar spindlesrdquoCell vol 81 no 1 pp 95ndash105 1995

[3] J M Schumacher N Ashcroft P J Donovan and A GoldenldquoA highly conserved centrosomal kinase AIR-1 is required foraccurate cell cycle progression and segregation of developmen-tal factors in Caenorhabditis elegans embryosrdquo Developmentvol 125 no 22 pp 4391ndash4402 1998

[4] J M Schumacher A Golden and P J Donovan ldquoAIR-2 anAuroraIpl1-related protein kinase associated with chromo-somes and midbody microtubules is required for polar bodyextrusion and cytokinesis in Caenorhabditis elegans embryosrdquoJournal of Cell Biology vol 143 no 6 pp 1635ndash1646 1998

[5] J R Bischoff and G D Plowman ldquoThe AuroraIpl1p kinasefamily regulators of chromosome segregation and cytokinesisrdquoTrends in Cell Biology vol 9 no 11 pp 454ndash459 1999

[6] M Tanaka A Ueda H Kanamori et al ldquoCell-cycle-dependentregulation of human auroraA transcription ismediated by peri-odic repression of E4TF1rdquo The Journal of Biological Chemistryvol 277 no 12 pp 10719ndash10726 2002

[7] J Zwicker F C Lucibello L A Wolfraim et al ldquoCell cycleregulation of the cyclin A cdc25C and cdc2 genes is based on acommon mechanism of transcriptional repressionrdquoThe EMBOJournal vol 14 no 18 pp 4514ndash4522 1995

[8] T Uchiumi D L Longo and D K Ferris ldquoCell cycle regulationof the human polo-like kinase (PLK) promoterrdquo Journal of Bio-logical Chemistry vol 272 no 14 pp 9166ndash9174 1997

[9] RD Fontijn BGoudA Echard et al ldquoThehumankinesin-likeprotein RB6K is under tight cell cycle control and is essential forcytokinesisrdquo Molecular and Cellular Biology vol 21 no 8 pp2944ndash2955 2001

[10] F Nikulenkov C Spinnler H Li et al ldquoInsights into p53 tran-scriptional function via genome-wide chromatin occupancyand gene expression analysisrdquo Cell Death and Differentiationvol 19 no 2 pp 1992ndash2002 2012

[11] D Fanale V Bazan L R Corsini et al ldquoHIF-1 is involved in thenegative regulation of AURKA expression in breast cancer celllines under hypoxic conditionsrdquo Breast Cancer Research andTreatment vol 140 no 3 pp 505ndash517 2013

[12] S Lee V Cimica N Ramachandra D Zagzag and G VKalpana ldquoAurora A is a repressed effector target of the chro-matin remodeling protein INI1hSNF5 required for rhabdoidtumor cell survivalrdquo Cancer Research vol 71 no 9 pp 3225ndash3235 2011

[13] K Latha M Li V Chumbalkar et al ldquoNuclear EGFRvIII-STAT5b complex contributes to glioblastoma cell survival bydirect activation of the Bcl-XL promoterrdquo International Journalof Cancer vol 132 no 3 pp 509ndash520 2013

[14] D M Murphy P G Buckley S Das K M Watters K Bryanand R L Stallings ldquoCo-localization of the oncogenic transcrip-tion factorMYCNand theDNAmethyl binding proteinMeCP2at genomic sites in neuroblastomardquo PLoS ONE vol 6 no 6Article ID e21436 2011

[15] KWakahara TOhnoMKimura et al ldquoEWS-Fli1 up-regulatesexpression of the Aurora A and Aurora B kinasesrdquo MolecularCancer Research vol 6 no 12 pp 1937ndash1945 2008

[16] T Furukawa N Kanai H O Shiwaku N Soga A Uehara andA Horii ldquoAURKA is one of the downstream targets of MAPK1ERK2 in pancreatic cancerrdquo Oncogene vol 25 no 35 pp 4831ndash4839 2006

[17] TMarumoto D Zhang andH Saya ldquoAurora-Amdasha guardian ofpolesrdquo Nature Reviews Cancer vol 5 no 1 pp 42ndash50 2005

[18] V M Bolanos-Garcia ldquoAurora kinasesrdquoThe International Jour-nal of Biochemistry amp Cell Biology vol 37 no 8 pp 1572ndash15772005

[19] M Carmena and W C Earnshaw ldquoThe cellular geography ofAurora kinasesrdquo Nature Reviews Molecular Cell Biology vol 4no 11 pp 842ndash854 2003

[20] Y Arlot-Bonnemains A Klotzbucher R Giet R Uzbekov RBihan and C Prigent ldquoIdentification of a functional destruc-tion box in the Xenopus laevis aurora-A kinase pEg2rdquo FEBSLetters vol 508 no 1 pp 149ndash152 2001

[21] A Castro Y Arlot-Bonnemains S Vigneron J C Labbe CPrigent and T Lorca ldquoAPCFizzy-related targets Auroramdashakinase for proteolysisrdquo EMBOReports vol 3 no 5 pp 457ndash4622002

[22] A S Nikonova I Astsaturov I G Serebriiskii R L DunbrackJr and E A Golemis ldquoAurora A kinase (AURKA) in normaland pathological cell divisionrdquo Cellular and Molecular LifeSciences vol 70 no 4 pp 661ndash687 2013

[23] M Kimura C Uchida Y Takano M Kitagawa and Y OkanoldquoCell cycle-dependent regulation of the human aurora B pro-moterrdquo Biochemical and Biophysical Research Communicationsvol 316 no 3 pp 930ndash936 2004

[24] F Shu S Guo Y Dang et al ldquoHuman Aurora-B binds to aproteasome 120572-subunit HC8 and undergoes degradation in aproteasome-dependent mannerrdquo Molecular and Cellular Bio-chemistry vol 254 no 1-2 pp 157ndash162 2003

[25] J Tsou K Chang P Chang-Liao et al ldquoAberrantly expressedAURKC enhances the transformation and tumourigenicity ofepithelial cellsrdquo Journal of Pathology vol 225 no 2 pp 243ndash254 2011

[26] E Baldini S Sorrenti E DrsquoArmiento et al ldquoAurora kinases newmolecular targets in thyroid cancer therapyrdquo Clinica Terapeu-tica vol 163 no 6 pp e457ndashe462 2012

[27] V Joukov A De Nicolo A Rodriguez J C Walter and D MLivingston ldquoCentrosomal protein of 192 kDa (Cep192) pro-motes centrosome-driven spindle assembly by engaging inorganelle-specific Aurora A activationrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 107 no 49 pp 21022ndash21027 2010

[28] D Berdnik and J A Knoblich ldquoDrosophila Aurora-A is requi-red for centrosome maturation and actin-dependent asymmet-ric protein localization during mitosisrdquo Current Biology vol 12no 8 pp 640ndash647 2002

[29] C P CDe Souza K AO Ellem andBGGabrielli ldquoCentroso-mal and cytoplasmicCdc2cyclin B1 activation precedes nuclearmitotic eventsrdquo Experimental Cell Research vol 257 no 1pp 11ndash21 2000

[30] A Seki J A Coppinger C Jang J R Yates III and G FangldquoBora and the kinase Aurora A cooperatively activate the kinasePlk1 and control mitotic entryrdquo Science vol 320 no 5883 pp1655ndash1658 2008

[31] S DutertreM Cazales M Quaranta et al ldquoPhosphorylation ofCDC25B byAuroramdasha at the centrosome contributes to theG2-M transitionrdquo Journal of Cell Science vol 117 part 12 pp 2523ndash2531 2004


[32] R D Van Horn S Chu L Fan et al ldquoCdk1 activity is requiredfor mitotic activation of Aurora A during G

2M transition of

human cellsrdquo The Journal of Biological Chemistry vol 285 no28 pp 21849ndash21857 2010

[33] S Ulisse E Baldini M Toller et al ldquoTransforming acidiccoiled-coil 3 and Aurora-A interact in human thyrocytes andtheir expression is deregulated in thyroid cancer tissuesrdquoEndocrine-Related Cancer vol 14 no 3 pp 827ndash837 2007

[34] K Kinoshita T L Noetzel L Pelletier et al ldquoAurora A phos-phorylation of TACC3maskin is required for centrosome-dependent microtubule assembly inmitosisrdquoThe Journal of CellBiology vol 170 no 7 pp 1047ndash1055 2005

[35] T P Barros K Kinoshita A A Hyman and J W Raff ldquoAuroraA activates D-TACC-Msps complexes exclusively at centro-somes to stabilize centrosomal microtubulesrdquo Journal of CellBiology vol 170 no 7 pp 1039ndash1046 2005

[36] S Ruchaud M Carmena and W C Earnshaw ldquoChromosomalpassengers conducting cell divisionrdquoNature ReviewsMolecularCell Biology vol 8 no 10 pp 798ndash812 2007

[37] G Vader R H Medema and S M A Lens ldquoThe chromosomalpassenger complex guiding Aurora-B through mitosisrdquo TheJournal of Cell Biology vol 173 no 6 pp 833ndash837 2006

[38] M S van derWaal R C C Hengeveld A van der Horst and SM A Lens ldquoCell division control by the Chromosomal Passen-ger Complexrdquo Experimental Cell Research vol 318 no 12 pp1407ndash1420 2012

[39] K Sasai H Katayama D L Stenoien et al ldquoAurora-C kinase isa novel chromosomal passenger protein that can complementAurora-B kinase function in mitotic cellsrdquo Cell Motility and theCytoskeleton vol 59 no 4 pp 249ndash263 2004

[40] S D Slattery M A Mancini B R Brinkley and R M HallldquoAurora-C kinase supportsmitotic progression in the absence ofAurora-Brdquo Cell Cycle vol 8 no 18 pp 2984ndash2994 2009

[41] J C Gabillard S Ulisse E Baldini et al ldquoAurora-C interactswith and phosphorylates the transforming acidic coiled-coil1 proteinrdquo Biochemical and Biophysical Research Communica-tions vol 408 no 4 pp 647ndash653 2011

[42] N Conte E Charafe-Jauffret B Delaval et al ldquoCarcinogenesisand translational controls TACC1 is down-regulated in humancancers and associates with mRNA regulatorsrdquo Oncogene vol21 no 36 pp 5619ndash5630 2002

[43] D Spengler ldquoThe protein kinase Aurora-C phosphorylatesTRF2rdquo Cell Cycle vol 6 no 20 pp 2579ndash2580 2007

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

[45] D J Gordon B Resio and D Pellman ldquoCauses and conse-quences of aneuploidy in cancerrdquo Nature Reviews Genetics vol13 no 3 pp 189ndash203 2012

[46] J R Bischoff L Anderson Y Zhu et al ldquoA homologue ofDrosophila aurora kinase is oncogenic and amplified in humancolorectal cancersrdquoThe EMBO Journal vol 17 no 11 pp 3052ndash3065 1998

[47] T Ota S Suto H Katayama et al ldquoIncreased mitotic phos-phorylation of histone H3 attributable to AIM-1aurora-Boverexpression contributes to chromosome number instabilityrdquoCancer Research vol 62 no 18 pp 5168ndash5177 2002

[48] J Khan F Ezan J Cremet et al ldquoOverexpression of activeAurora-C kinase results in cell transformation and tumourformationrdquo PLoS ONE vol 6 no 10 Article ID e26512 2011

[49] M Tatsuka S Sato S Kitajima et al ldquoOverexpression ofAurora-A potentiates HRAS-mediated oncogenic transforma-tion and is implicated in oral carcinogenesisrdquoOncogene vol 24no 6 pp 1122ndash1127 2005

[50] A Kanda H Kawai S Suto et al ldquoAurora-BAIM-1 kinaseactivity is involved in Ras-mediated cell transformationrdquoOnco-gene vol 24 no 49 pp 7266ndash7272 2005

[51] A A Dar LWGoff SMajid J Berlin andW El-Rifai ldquoAurorakinase inhibitorsmdashrising stars in cancer therapeuticsrdquoMolecu-lar Cancer Therapeutics vol 9 no 2 pp 268ndash278 2010

[52] W Lok R Q Klein andMW Saif ldquoAurora kinase inhibitors asanti-cancer therapyrdquo Anti-Cancer Drugs vol 21 no 4 pp 339ndash350 2010

[53] S Anand S Penrhyn-Lowe and A R VenkitaramanldquoAURORA-A amplification overrides the mitotic spindleassembly checkpoint inducing resistance to TaxolrdquoCancer Cellvol 3 no 1 pp 51ndash62 2003

[54] X Liang DWang YWang Z Zhou J Zhang and J Li ldquoExpression of Aurora Kinase A and B in chondrosarcoma and itsrelationshipwith the prognosisrdquoDiagnostic Pathology vol 7 no1 article 84 2012

[55] Z G Liu W Yi Y L Tao H C Chan M Zeng and Y XialdquoAurora-A is an efficient marker for predicting poor prognosisin human nasopharyngeal carcinoma with aggressive localinvasion 208 cases with a 10-year follow-up from a singleinstitutionrdquo Oncology Letters vol 3 no 6 pp 1237ndash1244 2012

[56] H R Ali S-J Dawson F M Blows E Provenzano P DPharoah andC Caldas ldquoAurora kinaseA outperformsKi67 as aprognostic marker in ER-positive breast cancerrdquo British Journalof Cancer vol 106 no 11 pp 1798ndash1806 2012

[57] N L Lehman J P OrsquoDonnell L J Whiteley et al ldquoAurora A isdifferentially expressed in gliomas is associated with patientsurvival in glioblastoma and is a potential chemotherapeutictarget in gliomasrdquo Cell Cycle vol 11 no 3 pp 489ndash502 2012

[58] E Dotan N J Meropol F Zhu et al ldquoRelationship of increasedaurora kinase A gene copy number prognosis and responseto chemotherapy in patients with metastatic colorectal cancerrdquoBritish Journal of Cancer vol 106 no 4 pp 748ndash755 2012

[59] J Wang S Yang H Zhang et al ldquoAurora-A as an independentmolecular prognostic marker in gastric cancerrdquo OncologyReports vol 26 no 1 pp 23ndash32 2011

[60] F Yang X Guo G Yang D G Rosen and J Liu ldquoAURKA andBRCA2 expression highly correlate with prognosis of endo-metrioid ovarian carcinomardquo Modern Pathology vol 24 no 6pp 836ndash845 2011

[61] R A Bibby C Tang A Faisal et al ldquoA cancer-associatedAuroraA mutant is mislocalized and misregulated due to loss of inter-action with TPX2rdquoThe Journal of Biological Chemistry vol 284no 48 pp 33177ndash33184 2009

[62] K B Lukasiewicz and W L Lingle ldquoAurora A centrosomestructure and the centrosome cyclerdquo Environmental andMolec-ular Mutagenesis vol 50 no 8 pp 602ndash619 2009

[63] H G Nguyen M Makitalo D Yang D Chinnappan C StHilaire and K Ravid ldquoDeregulated Aurora-B inducedtetraploidy promotes tumorigenesisrdquo The FASEB Journal vol23 no 8 pp 2741ndash2748 2009

[64] G Pannone S A H Hindi A Santoro et al ldquoAurora Bexpression as a prognostic indicator and possibile therapeutictarget in oral squamous cell carcinomardquo International Journal ofImmunopathology and Pharmacology vol 24 no 1 pp 79ndash882011


[65] Z Lin Y Jeng F Hu et al ldquoSignificance of Aurora B overexpres-sion in hepatocellular carcinoma Aurora B Overexpression inHCCrdquo BMC Cancer vol 10 article 461 2010

[66] M Kimura Y Matsuda T Yoshioka and Y Okano ldquoCell cycle-dependent expression and centrosome localization of a thirdhuman AuroraIpl1-related protein kinase AIK3rdquo The Journalof Biological Chemistry vol 274 no 11 pp 7334ndash7340 1999

[67] S Ulisse J Delcros E Baldini et al ldquoExpression of Aurorakinases in human thyroid carcinoma cell lines and tissuesrdquoInternational Journal of Cancer vol 119 no 2 pp 275ndash282 2006

[68] E Baldini Y Arlot-BonnemainsMMottolese et al ldquoDeregula-tion of Aurora kinase gene expression in human testicular germcell tumoursrdquo Andrologia vol 42 no 4 pp 260ndash267 2010

[69] E Baldini Y Arlot-Bonnemains S Sorrenti et al ldquoAurorakinases are expressed in medullary thyroid carcinoma (MTC)and their inhibition suppresses in vitro growth and tumori-genicity of the MTC derived cell line TTrdquo BMC Cancer vol 11article 411 2011

[70] E Manchado M Guillamot and M Malumbres ldquoKilling cellsby targeting mitosisrdquo Cell Death and Differentiation vol 19 no3 pp 369ndash377 2012

[71] C H A Cheung M S Coumar J Y Chang and H P HsiehldquoAurora kinase inhibitor patents and agents in clinical testingan update (2009ndash10)rdquo Expert Opinion on Therapeutic Patentsvol 21 no 6 pp 857ndash884 2011

[72] D Karthigeyan S B B Prasad J Shandilya S Agrawal and TK Kundu ldquoBiology of Aurora A kinase implications in cancermanifestation and therapyrdquoMedicinal Research Reviews vol 31no 5 pp 757ndash793 2011

[73] N Matthews C Visintin B Hartzoulakis A Jarvis and D LSelwood ldquoAurora A and B kinases as targets for cancer will theybe selective for tumorsrdquo Expert Review of Anticancer Therapyvol 6 no 1 pp 109ndash120 2006

[74] M Kollareddy D Zheleva P Dzubak P S BrahmkshatriyaM Lepsik andM Hajduch ldquoAurora kinase inhibitors progresstowards the clinicrdquo Investigational New Drugs vol 30 no 6 pp2411ndash2432 2012

[75] S Lapenna and A Giordano ldquoCell cycle kinases as therapeutictargets for cancerrdquo Nature Reviews Drug Discovery vol 8 no 7pp 547ndash566 2009

[76] D S Boss J H Beijnen and J H M Schellens ldquoClinicalexperience with Aurora kinase inhibitors a reviewrdquo Oncologistvol 14 no 8 pp 780ndash793 2009

[77] J J EM KitzenM J A de Jonge and J Verweij ldquoAurora kinaseinhibitorsrdquo Critical Reviews in OncologyHematology vol 73no 2 pp 99ndash110 2010

[78] S I Sherman ldquoThyroid carcinomardquo The Lancet vol 361 no9356 pp 501ndash511 2003

[79] A Jemal R Siegel E Ward Y Hao J Xu and M J ThunldquoCancer statistics 2009rdquo CA Cancer Journal for Clinicians vol59 no 4 pp 225ndash249 2009

[80] P Trimboli S Ulisse F M Graziano et al ldquoTrend in thyroidcarcinoma size age at diagnosis and histology in a retrospectivestudy of 500 cases diagnosed over 20 yearsrdquoThyroid vol 16 no11 pp 1151ndash1155 2006

[81] N K Patel and A R Shaha ldquoPoorly differentiated thyroidcancerrdquo Current Opinion in Otolaryngology amp Head amp NeckSurgery vol 22 no 2 pp 121ndash126 2014

[82] J L Pasieka ldquoAnaplastic thyroid cancerrdquo Current Opinion inOncology vol 15 no 1 pp 78ndash83 2003

[83] Y E Nikiforov Diagnostic Pathology and Molecular Genetics ofthe Thyroid Lippincott Williams amp Wilkins Philadelphia PaUSA 2009

[84] Y E Nikiforov and M N Nikiforova ldquoMolecular genetics anddiagnosis of thyroid cancerrdquoNature Reviews Endocrinology vol7 no 10 pp 569ndash580 2011

[85] A Guerra V di Crescenzo and A Garzi ldquoGenetic mutations inthe treatment of anaplastic thyroid cancer a systematic reviewrdquoBMC Surgery vol 13 no 2 article S44 2013

[86] M A Huber N Kraut and H Beug ldquoMolecular requirementsfor epithelial-mesenchymal transition during tumor progres-sionrdquoCurrent Opinion in Cell Biology vol 17 no 5 pp 548ndash5582005

[87] VVasko AV EspinosaW Scouten et al ldquoGene expression andfunctional evidence of epithelial-to-mesenchymal transitionin papillary thyroid carcinoma invasionrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 104 no 8 pp 2803ndash2808 2007

[88] E BaldiniM Toller FM Graziano et al ldquoExpression ofmatrixmetalloproteinases and their specific inhibitors in normal anddifferent human thyroid tumor cell linesrdquo Thyroid vol 14 no11 pp 881ndash888 2004

[89] S Ulisse E Baldini M Toller et al ldquoDifferential expression ofthe components of the plasminogen activating system in humanthyroid tumour derived cell lines and papillary carcinomasrdquoEuropean Journal of Cancer vol 42 no 15 pp 2631ndash2638 2006

[90] S Ulisse E Baldini S Sorrenti et al ldquoHigh expression of theurokinase plasminogen activator and its cognate receptor asso-ciates with advanced stages and reduced disease-free interval inpapillary thyroid carcinomardquo Journal of Clinical Endocrinologyand Metabolism vol 96 no 2 pp 504ndash508 2011

[91] S Ulisse E Baldini S Sorrenti et al ldquoIn papillary thyroidcarcinomaBRAF119881600119864 is associatedwith increased expression ofthe urokinase plasminogen activator and its cognate receptorbut not with disease-free intervalrdquo Clinical Endocrinology vol77 no 5 pp 780ndash786 2012

[92] B Shahedian Y Shi M Zou and N R Farid ldquoThyroid car-cinoma is characterized by genomic instability evidence fromp53 mutationsrdquoMolecular Genetics and Metabolism vol 72 no2 pp 155ndash163 2001

[93] V B Wreesmann R A Ghossein S G Patel et al ldquoGenome-wide appraisal of thyroid cancer progressionrdquoAmerican Journalof Pathology vol 161 no 5 pp 1549ndash1556 2002

[94] K N Patel and A R Shaha ldquoPoorly differentiated and anaplas-tic thyroid cancerrdquo Cancer Control vol 13 no 2 pp 119ndash1282006

[95] C Passler C Scheuba G Prager et al ldquoPrognostic factors ofpapillary and follicular thyroid cancer differences in an iodine-replete endemic goiter regionrdquo Endocrine-Related Cancer vol11 no 1 pp 131ndash139 2004

[96] C F A Eustatia-Rutten E P M Corssmit N R Biermasz AM Pereira J A Romijn and J W Smit ldquoSurvival and deathcauses in differentiated thyroid carcinomardquo Journal of ClinicalEndocrinology and Metabolism vol 91 no 1 pp 313ndash319 2006

[97] A Antonelli P Fallahi S Ulisse et al ldquoNew targeted therapiesfor anaplastic thyroid cancerrdquo Anti-Cancer Agents in MedicinalChemistry vol 12 no 1 pp 87ndash93 2012

[98] R Sorrentino S Libertini P L Pallante et al ldquoAurora B overex-pression associates with the thyroid carcinoma undifferentiatedphenotype and is required for thyroid carcinoma cell prolifera-tionrdquo Journal of Clinical Endocrinology and Metabolism vol 90no 2 pp 928ndash935 2005


[99] S M Wiseman H Masoudi P Niblock et al ldquoAnaplastic thy-roid carcinoma Expression profile of targets for therapy offersnew insights for disease treatmentrdquoAnnals of Surgical Oncologyvol 14 no 2 pp 719ndash729 2007

[100] R F Rodrigues L Roque J Rosa-Santos O Cid and J SoaresldquoChromosomal imbalances associated with anaplastic trans-formation of follicular thyroid carcinomasrdquo British Journal ofCancer vol 90 no 2 pp 492ndash496 2004

[101] S Libertini A Abagnale C Passaro et al ldquoAZD1152 negativelyaffects the growth of anaplastic thyroid carcinoma cells andenhances the effects of oncolytic virus dl922-947rdquo Endocrine-Related Cancer vol 18 no 1 pp 129ndash141 2011

[102] Y Arlot-Bonnemains E Baldini B Martin et al ldquoEffects of theAurora kinase inhibitor VX-680 on anaplastic thyroid cancer-derived cell linesrdquo Endocrine-Related Cancer vol 15 no 2 pp559ndash568 2008

[103] E Baldini S Sorrenti E DrsquoArmiento et al ldquoEffects of theAurora kinases pan-inhibitor SNS-314 mesylate on anaplasticthyroid cancer derived cell linesrdquo Clinica Terapeutica vol 163no 5 pp e307ndashe313 2012

[104] E Baldini C Tuccilli N Prinzi et al ldquoThe dual Aurora kinaseinhibitor ZM447439 prevents anaplastic thyroid cancer cellgrowth and tumorigenicityrdquo Journal of Biological Regulators andHomeostatic Agents vol 27 no 3 pp 705ndash715 2013

[105] A Wunderlich M Fischer T Schloszlighauer et al ldquoEvaluationof Aurora kinase inhibition as a new therapeutic strategy inanaplastic and poorly differentiated follicular thyroid cancerrdquoCancer Science vol 102 no 4 pp 762ndash768 2011

[106] A Wunderlich S Roth A Ramaswamy et al ldquoCombinedinhibition of cellular pathways as a future therapeutic optionin fatal anaplastic thyroid cancerrdquo Endocrine vol 42 no 3 pp637ndash646 2012

[107] K C Bible V J Suman J RMolina et al ldquoEfficacy of pazopanibin progressive radioiodine-refractory metastatic differentiatedthyroid cancers results of a phase 2 consortium studyrdquo TheLancet Oncology vol 11 no 10 pp 962ndash972 2010

[108] K C Bible V J Suman M E Menefee et al ldquoA multiinsti-tutional phase 2 trial of pazopanib monotherapy in advancedanaplastic thyroid cancerrdquo Journal of Clinical Endocrinology andMetabolism vol 97 no 9 pp 3179ndash3184 2012

[109] C R IshamA R BossouVNegron et al ldquoPazopanib enhancespaclitaxel-induced mitotic catastrophe in anaplastic thyroidcancerrdquo Science Translational Medicine vol 5 no 166 p 166ra32013

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


COOH1 76 251 345

COOH1 8 249 309

COOH1 133 383 403

Activation loop D-boxA-boxDAD

KEN motif

Aurora-A

Aurora-B

Aurora-C

Catalytic domain

NH2

NH2

NH2

Figure 1 Schematic representation of Aurora kinase proteins D-box destruction box DAD D-box activating domain KEN motifamino acidic K-E-N which serves as targeting signal for the Cdh1-anaphase promoting complex

dependent transcriptional repressor is formed by tandemrepression elements consisting of a cell cycle dependent ele-ment (CDE) located at minus44 to minus40 (CGCCC) and a cell cyclegene homology region (CHR) located atminus39 tominus35 (TTAAA)[6] It is worth mentioning that in addition to Aurora-A the G2M specific transcription of different genes suchas cyclin A cdc25C cdc2 polo-like kinase and others isregulated by similar tandem repression elements [6ndash9] Overthe last few years a number of transcription factors capable ofmodulating the expression of AURKA gene have been identi-fied These include the p53 the HIF-1 and the INI1hSSNF5all reported to negatively regulate the activity of the AURKApromoter [10ndash12] Conversely the transcriptional activity ofthe AURKA promoter has been shown to increase followingthe interaction with the ΔEGFRSTAT5 complex in glioblas-toma cells [13] Moreover the oncogeneMYCN a member ofthe MYC family of basic helix-loop-helix transcription fac-tors has been described to bind the AURKA promoter eitheralone or in complex with the DNA methyl binding proteinMeCP2 in the neuroblastoma derived cell line Kelly [14]EWS-Fli1 a fusion gene resulting from the chromosomaltranslocation (11 22 q24 q12) encodes a transcriptional acti-vator capable of promoting cellular transformation in Ewingsarcoma cells Experimental evidence showed that EWS-Fli1protein upregulates Aurora-A and Aurora-B expression bybinding to regulatory ETS-binding sites located at minus84 andminus71 bp upstream of the transcription initiation sites in bothAurora-A and Aurora-B promoters [15] Similarly it has beensuggested that activation of the MAPK in pancreatic cancercells leads to the transcriptional activation of the AURKA andAURKB promoters via ETS2 transcription factors [16]

The 24 kb transcript from AURKA gene encodes aprotein of 403 amino acids with a predicted molecular massof 458 kDa (Figure 1) Like all Aurora proteins it is char-acterized by a C-terminal catalytic domain containing theactivation loop In the latter anAurora kinase signature (xRx-TxCGTx) is present in which the autophosphorylation of theThr288 is required for kinase activation [17] In addition theThr288 is positionedwithin a protein kinaseA (PKA) consen-sus sequence and in vitro experiments indicated a potential

role of PKA in Aurora-A phosphorylation [18 19] The phos-phatase PP1 has been shown to dephosphorylate and inacti-vate Aurora-A [19] The C-terminal located destruction box(D-box) containing the motif RxxLxxG and the N-terminalA-boxD-box activating domain (DAD) containing themotifRxLxPS play an essential role in Aurora-A degradation bythe anaphase promoting complexcyclosome- (APCC-)ubiquitin-proteasomepathwayAurora-Adegradation occursin late mitosisearly G1 phase when the D-box is targeted byFizzy related proteins that transiently interact with the APCand is hCdh1 dependent [18ndash21] In theN-terminal region theamino acidic sequence K-E-N known as KEN motif is alsopresent which serves as targeting signal for Cdh1-APCrequired also for the degradation of other mitotic proteinssuch as Nek2 and B99 [22] However this does not seem tobe crucial for Aurora-A degradation [22]

12 Aurora-B The Aurora-B is encoded by the AURKB gene(also known as AIK2 AIM1 ARK2 AurB IPL1 STK5 AIM-1 STK12) mapped to chromosome 17p131 and consisting of9 exons (Gene ID 9212)

The AURKB promoter contains three putative CAAT-boxes at minus99 to minus86 at minus66 to minus53 and at minus30 to minus17 (Eukary-otic PromoterDatabase Swiss Institute of Bioinformatics) Byprimer extension twomajor transcription initiation sites wereidentified [23] As for the Aurora-A promoter also theAurora-B promoter possesses the CDE and CHR elementsthough responsible for the cell cycle regulation of its expres-sion and several CDE-binding proteins have been identifiedby means of electrophoretic mobility shift assay and biotin-streptavidin pull-down assay including the E2F-1 E2F-4 andDP-2 [23] As above described the AURKB promoter maybe positively regulated by transcription factors such as theETS2 via ETS-binding sites present in the promoter sequence[15 16]

The 14 kb transcript encodes a protein of 345 aminoacids with a predicted molecular mass of 39 kDa (Figure 1)[5] As described for Aurora-A also the Aurora-B protein ischaracterized by a catalytic domain a C-terminal D-box andan N-terminal A-boxDAD [18ndash21] However althoughAurora-B possesses the same D-box as Aurora-A it is notdegraded by the same ubiquitin ligase but undergoes degra-dation following its binding to the human proteasome 120572-subunit C8 in a proteasome dependent manner [24]

13 Aurora-C TheAurora-C is encoded by the AURKC gene(also known as AIE2 AIK3 ARK3 AurC SPGF5 STK13)which localizes at chromosome 19q1343 and consists of 7exons (Gene ID 6795)

The AURKC promoter contains a CCAAT-box at minus36 tominus23 (Eukaryotic Promoter Database Swiss Institute of Bioin-formatics) Expression of AURKC is downregulated by PLZFa transcriptional repressor through recruitment to its pro-moter region and it is of interest to note that the expressionlevels of PLZF andAURKCmRNAs display opposite patternsin human cervical and colorectal cancers [25]

The 13 kb transcript encodes a protein of 309 aminoacids with a predicted molecular mass of 356 kDa (Figure 1)













Aurora-A

PLK1

Bora Wee1

CDC25Cyclin B

Cdk1

Cyclin B

Cdk1

Mitotic entry

Centrosome

(a)


(b)








Aurora-B


(a)

Aurora-B

Tubulin


(b)


















4 Thyroid Cancers













Acknowledgment



References


































2M transition of






















































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of




























Aurora-A

PLK1

Bora Wee1

CDC25Cyclin B

Cdk1

Cyclin B

Cdk1

Mitotic entry

Centrosome

(a)


(b)








Aurora-B


(a)

Aurora-B

Tubulin


(b)


















4 Thyroid Cancers













Acknowledgment



References


































2M transition of






















































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















Aurora-A

PLK1

Bora Wee1

CDC25Cyclin B

Cdk1

Cyclin B

Cdk1

Mitotic entry

Centrosome

(a)


(b)








Aurora-B


(a)

Aurora-B

Tubulin


(b)


















4 Thyroid Cancers













Acknowledgment



References


































2M transition of






















































































of






Disease Markers



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Acknowledgment



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2M transition of






















































































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Documents

Review Article A New Aurora in Anaplastic Thyroid Cancer ...downloads.hindawi.com/journals/ije/2014/816430.pdf · A New Aurora in Anaplastic Thyroid Cancer Therapy EnkeBaldini,MassiminoD