De la farmacogenética a la farmacogenómica Javier Benitez Programa Genética del Cáncer Humano Centro Nacional Investigaciones Oncológicas Madrid Junio 06

Antitumoral treatments -They are agressives, inspecifics and with a limited therapeutic margin. - Risk of toxicity, treatment failure or even death - Wide interpatient variability in effects

Antitumoral treatments II -Children with ALL. 75% get total remision (cure) 25% with treatment failure and/or severe toxicity -Sarcomas: 50-75% long term survival (cure) Cases with severe toxicity CNS and GUS - Breat cancer: Tamoxifen for ER and PR positive tumors (50%) Secondary effects in some patients: Uterine cancer, tromboembolims

- Genetic variability might explain many of these situations. -Their study could lead to individualised treatment and new drug developments. -Pharmacogenetics: It studies candidate genes -Pharmacogenomics: It describes a broader strategy to identify many genes that are relevant to the pharmacological effects of a given medication. It is based in a targeted (candidate pathways) or whole genome analysis. Genetic bases of farmacological response

Enzimatic activity of TPMT-6MP according to genotype Cheok et al, Nat Review 2006

Correlation between TPMT genotype and 6MP toxicity Cheok et al, Nat Review 2006

40 SNPs from 14 genes No differences with other populations More genes under study Allelic frequencies in Spanish Population ( MTFR and MTX TPMT and 6MP G238C G460A A719C 100 patients with ALL (

Entry 2- Degradation 3- target 4- metabolyze 5-…………….. …………. They study 32 genes from this pathway and identify some of them associated to MTX resistence. They found differences among ALL subtypes. Strategy II. MTX pathway (folate analogue) Kager et al. J Clin Invest 2005

Strategy III. Genome Wide Approach Global gene expression profiling using DNA microarrays can identify: - genes with levels of expression that are related to drug response. - New drug targets It is a complementary strategy to the identification of SNPs in genes that alter protein function and drug response.

Expression Profiling of T-Cell Lymphomas Differentiates Peripheral and Lymphoblastic Lymphomas and Defines Survival Related Genes Martinez Delgado et al.Clin. Cancer Res, PTCLLB NFkBNFkB Median OS = 10 months P= >10 m <10 m Treatment response/ survival Genetic signature: 6 genes 165 genes differenciate both groups

CYP3A4 CYP3A7 CYP51 CYP8B1 A cluster of CYP3As genes is associated with evolution Martinez Delgado et al. Leukemia 2005

PTCLs Normalized CYP3A4 expression Log Rank p=0.001 Expression of CYP3A4 is associated to survival of PTCLs CYP3A4 is an important drug metabolizing enzyme, CYP3A4 expression in tumors could then be mediating the response to chemotherapy. Detection of CYP3A4 expression could have clinical interest by identifying tumors more resistant to chemotherapy at the time of diagnosis. An alternative treatment? Martinez Delgado et al. (in preparation)

PROLIFERATION Genes correlated to proliferation not specifically related to cell cycle regulation: HSP90 Inhibitors of HSP90 (17AAG) under study -No effect in normal lymphocytes -Good response in peripheral T cell lines Marta Cuadros et al. In preparation Periferal T-cell lymphomas: HSP90 as drug target HSP90 is a chaperone HSP family inhibits apoptotic pathways Overexpression of HSP90 - bad prognosis

Conclusions - Pharmacogenetics is starting to be introduced and applied in the clinical practice (6MP; MTX.....) - The study of the response based on multiple genes (polygenic model) is now underway - Pharmacogenomics permits the identification of new therapeutic targets and groups of genes that modulate the pharmacological response. - It is still necessary to validate data. Problems with population variability, techniques, platforms etc....

Acknowledgements Human Genetics Lab: Lara P. Fernandez Eva Barroso Goria Ribas Beatriz Martinez Marta Cuadros CeGen Madrid Genotyping Lab: Emilio Gonzalez Roger Milner Ana Gonzalez Charo Jesus Mari Endocrine Group: Mercedes Robledo Fátima Mercadillo Cristina Rodriguez Genotyping Lab