Angiotherapy and gene therapy in Angiotherapy and gene therapy in cancer treatmentcancer treatment

These slides provide an overview of angiotherapy and gene therapy in cancer

Dr. Momna Hejmadi, University of Bath

N.B. Some images used in these slides are from the textbooks listed and are not covered under the Creative Commons license as yet

This resource created by Dr. Momna Hejmadi, University of Bath, 2010, is licensed under the Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

Newer cancer therapiesNewer cancer therapies

AngiotherapyAngiotherapy

use of agents that inhibit angiogenesisuse of agents that inhibit angiogenesis

Angiogenesis-overviewAngiogenesis-overview

Nature Reviews Drug Discovery 1, 415-426 (2002)

EndostatinEndostatin Discovered in 1995 by Judah Folkman et alDiscovered in 1995 by Judah Folkman et al Phase I clinical trial in 1999Phase I clinical trial in 1999Dr. James Watson predicted that Dr. Folkman would cure all Dr. James Watson predicted that Dr. Folkman would cure all

cancer within 2 yearscancer within 2 years

Dr. Folkman’s responseDr. Folkman’s response““If you are a mouse and have cancer we can If you are a mouse and have cancer we can take good care of you. However, in our take good care of you. However, in our experiments we mostly sacrifice the mice. So, I experiments we mostly sacrifice the mice. So, I don't know if that qualifies as taking good don't know if that qualifies as taking good care”care”

Angiogenesis: an organizing principle for drug discovery by Judah Folkman

Nature Reviews Drug Discovery 6, 273-286 (April 2007)

(Courtesy of L. Heuser and R. Ackland, University of Louisville, USA

Categories of anti-angiogenicsCategories of anti-angiogenicsAnti-angiogenic molecules fall into 5 categories inhibitors of angiogenic growth factors:VEGF, bFGF, PDGF protease inhibitors: prevents the breakdown of the

surrounding matrix, which is needed for blood-vessel growth

Analogs of endogenous inhibitors of angiogenesis e.g. endostatin;

inhibitors of cellular adhesion molecules molecules with undefined mechanisms

‘‘cryptic’ angiogenesis inhibitorscryptic’ angiogenesis inhibitors

AngiostatinAngiostatin 38kDa fragment of 38kDa fragment of

plasminogenplasminogen

EndostatinEndostatin 20kDa fragment of collagen 20kDa fragment of collagen

XVIIIXVIII Endothelial cell specificEndothelial cell specific Complete regression in miceComplete regression in mice No drug resistanceNo drug resistance

Inactive until released from the parent protein by enzymatic cleavage

FDA approved drugsFDA approved drugs

Anti-VEGFR2 Anti-VEGFR2 therapytherapy

(c,d) Anti-VEGFR2 prunes immature vessels, leading to a progressively 'normalized' vasculature(e) Further treatment leads to a vasculature that is inadequate to sustain tumour growth by day 5. (f) Perivascular cells expressing GFP (under the control of the VEGF promoter) envelope some vessels in the tumour interior. (g) A perivascular cell, presumably a fibroblast, leading the endothelial sprout (arrow).

Before treatment after treatment

Efficacy of thalidomide as an anti-angiogenic agentEfficacy of thalidomide as an anti-angiogenic agent

Blood-flow maps a | before treatment and b | six months aftertreatment of a patient with metastatic renal-cell carcinoma with thalidomide.

Haematological malignancies?Haematological malignancies?Neovasculature around bone marrow in certain

leukaemias. Anti-angiogenic drugs could therefore be useful in haematolgical malignancies

Bone marrow from a child with newly diagnosed acute lymphoblastic leukaemia reveals intense neovascularization, with microvessels of variable diameters.

normal bone marrow (from a child with a non-neoplastic

disease) shows normal microvasculature of uniform-

sized vessels.

Timeline of anti-angiogenic drugsTimeline of anti-angiogenic drugs

Combination with chemotherapyCombination with chemotherapyDosing schedule differences between conventional Dosing schedule differences between conventional chemotherapy (red) and anti-angiogenic chemotherapychemotherapy (red) and anti-angiogenic chemotherapy

ReferencesReferences

1) Angiogenesis modulation in cancer research:Novel clinical 1) Angiogenesis modulation in cancer research:Novel clinical approaches by approaches by M Cristofanilli, C Charnsangavej‡ M Cristofanilli, C Charnsangavej‡ and GN.Hortobagyiand GN.Hortobagyi

Nature reviews drug discovery VOL 1 JUNE pp 415 (2002)Nature reviews drug discovery VOL 1 JUNE pp 415 (2002)

2) 2) Angiogenesis: an organizing principle for drug discovery by Judah Folkman

Nature Reviews Drug Discovery 6, 273-286 (April 2007)

Newer cancer therapiesNewer cancer therapies

gene therapygene therapy

Direct genetic modification of cells in patients

deliverydelivery

3 challenges in gene therapy3 challenges in gene therapy

deliverydelivery deliverydelivery

1)1) Package the genePackage the gene2)2) Protect the geneProtect the gene3)3) targeted delivery to the nucleus and targeted delivery to the nucleus and

release in an active formrelease in an active form

Carrier molecules designed specifically Carrier molecules designed specifically

to enter cells & deposit therapeutic to enter cells & deposit therapeutic

genesgenes

Vectors ‘Trojan horses’ that sneak the gene into the cell

METHODS OF VECTOR DELIVERYMETHODS OF VECTOR DELIVERY

Viral vector strategyViral vector strategyReplication & virulence genes can be Replication & virulence genes can be

substituted with therapeutic genessubstituted with therapeutic genes

designed to enter cell and deposit genesdesigned to enter cell and deposit genes

Specially constructed Specially constructed to prevent the generation to prevent the generation

of replication competent retroviruses (RCR)of replication competent retroviruses (RCR)

Retroviral vectorsRetroviral vectors

AdvantagesAdvantages• long-term expression long-term expression • low toxicity low toxicity • high capacity high capacity • low antivector low antivector

immunityimmunity

ProblemsProblems• Lack of cell specificityLack of cell specificity• Random splicing into Random splicing into

host DNAhost DNA

Minimal HIV vector plasmid

All genes coding for enzymatic or structural HIV proteins have been removed.(1) consisting of the CMV/HIV LTR hybrid promoter followed by the packaging signal ( Ψ), the rev-binding element RRE for cytoplasmic export of the RNA, the transgene expression cassette consisting of internal promoter(s) and transgene(s), and the 3' self-inactivating (SIN) LTR. Together with the HIV vector plasmid (1), the HIV packaging plasmid (2), HIV rev (3), and an envelope expressing plasmid (4) are needed for HIV vector production.

Gene Therapy (2005) 12, 1089–1098

Adenoviral vectorsAdenoviral vectors

do not insert into genome

temporary

lack of specificity

strong immune response

Adeno-associated viral vectorsAdeno-associated viral vectors

Nature Reviews Genetics 1; 91-99 (2000);

Integrate into genome but small in size

Non-toxicNon-toxic

no immune responseno immune response

reduced specificityreduced specificity

Non-viral VectorsNon-viral Vectors

Non-viral VectorsNon-viral Vectors

liposomes (liposomes (lipoplexeslipoplexes)) Gene gun

clinical trials by vector

27%

12%

11%

2% 7%6%

34%

retrovirusadenoviruslipofectionnaked DNApox virusAAVothers

Germ line gene therapyGerm line gene therapy

Somatic cell gene therapySomatic cell gene therapy

Gene augmentationGene augmentation

Gene replacementGene replacement

Specific inhibition of gene expressionSpecific inhibition of gene expression

Targeted cell death Targeted cell death

Gene therapy targetsGene therapy targets

Gene augmentationGene augmentationmost therapies simply add a useful gene into a selected cell type to most therapies simply add a useful gene into a selected cell type to

compensate for the missing or flawed version. compensate for the missing or flawed version.

Useful in treating loss of function mutations such as Tumour suppressor genesUseful in treating loss of function mutations such as Tumour suppressor genes

Gene replacementGene replacement

This strategy replaces the mutant copy with a correctly This strategy replaces the mutant copy with a correctly functioning copy in situ. functioning copy in situ.

Useful for gain of function mutations such as oncogenesUseful for gain of function mutations such as oncogenes

Specific inhibition of gene expressionSpecific inhibition of gene expressionInvolves silencing of specific genes like activated oncogenes, Involves silencing of specific genes like activated oncogenes,

by using molecules that degrade RNA transcripts. by using molecules that degrade RNA transcripts. Strategies includeStrategies include

Antisense therapyAntisense therapysiRNA (siRNA (small interfering RNA)small interfering RNA)Ribozymes etcRibozymes etc

Targeted cell deathTargeted cell death

Tissue-specific delivery of drugs using vectors resulting in Tissue-specific delivery of drugs using vectors resulting in tissue specific toxicity. tissue specific toxicity.

Direct approachDirect approach

Targeted cell deathTargeted cell deathIndirect approachIndirect approach

stimulating an immune response against selected stimulating an immune response against selected cells or eliminating the blood supply.cells or eliminating the blood supply.

Gene therapy in cancerGene therapy in cancergene therapy clinical trials

12%

6%

8%10%

64%

cancer

monogenic disease

infectious disease

vascular disease

others

http://www.wiley.co.uk/genetherapy/clinical/

Some examples Some examples

Severe Combined Immunodeficiency

(SCID)

Rare condition caused by the lack or reduction in the immune system (‘bubble baby syndrome’)

Patients cannot make T lymphocytes and their B lymphocytes fail to make essential antibodies for fighting infections.

Gene therapy in X-SCID patients

X-SCID caused by mutations in the X-linked gene IL2RG, which encodes the common gamma chain (gc) of the lymphocyte receptors for interleukin-2 (IL-2) and many other cytokines

Gene therapy by injection of retrovirally transduced autologous CD34+ hematopoietic stem cells (HSCs).

insertional mutagenesis near the proto-oncogene LMO2 promoter (Science, 302:415-419, October 17, 2003)

2/11 X-SCID patients developed 2/11 X-SCID patients developed leukemialeukemia

ReferencesReferences

Chapter 16: Biology of Cancer by RA Chapter 16: Biology of Cancer by RA Weinberg Weinberg

Human gene therapy by Ioannou, Panos A(www.els.net)

Nature Reviews Cancer (2001) vol 1 pp 130-141 by Francis McCormick