P.J.: PM1183 inhibe de manera selectiva la transcripción activada y también bloquea la vía de reparación de ADN llamada nucelotide excision repair (NER) provocando una acumulación letal de daños en el material genético, que induce la muerte por apoptosis de las células tumorales. PM01183 iniciara este año 2015 Dos Ensayos Pivotales en la indicaciones de Cáncer de Ovario Resistente a Platinos y en SCLC ( Pulmón Small ) .
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Sera Presentado este Lunes en el Congreso Anual de la Asociación Americana para la Investigación del Cáncer (AACR) que Tiene lugar en Filadelfia (EE.UU.) del 18 al 22 de abril.
Abstract Number: 2520
Presentation Title: Synergistic combination of lurbinectedin and PARP inhibitors in breast cancer tumor cell lines .
Abstrac que se Presentara el proximo Lunes dia 20 en el Congreso de la AACR .
Presentation Time: Monday, Apr 20, 2015, 1:00 PM - 5:00 PM
Author Block:
Gema Santamaría, Sonia Avila, Victoria Moneo, Carmen Cuevas, Luis F. García-Fernández, Carlos M. Galmarini. PharmaMar S.A., Madrid, Spain
Abstract Body:
Lurbinectedin (PM1183) is a new tetrahydroisoquinoline derivative currently evaluated in phase II trials in BRCA1-mutated breast cancer and NSCLC patients. Two pivotal trials (in platinum-resistant ovarian cancer and in SCLC) will be launched in 2015.
PM1183 shows antitumor activity against a wide variety of tumor cells with mean IC50 values in the low nanomolar range. In living cells, PM1183 inhibits trans-activated transcription and blocks NER-dependent DNA repair inducing the formation of dsDNA breaks and the collapse of replication forks that need to be repaired by homologous recombination (HR). As expected, PM1183 is more active against homologous recombination (HR)-deficient cell lines. In this work, we evaluated the in vitro antitumor effect of PM1183 when combined with the PARP inhibitors ABT-88 (Veliparib, PARP-1 and -2), AZD-2281 (Olaparib, PARP-1), BSI-201 (Iniparib, PARP-1) and BMN-673 (PARP-1 and -2) (Selleck Chemicals, Houston, TX, USA) in a panel of human breast carcinoma cells with different BRCA1 status, including MCF-7 (BRCA1 +/+), MDA-MB-231 (BRCA1 +/-), HCC-1937 (BRCA1 -/-) and MDA-MB-436 (BRCA1 -/-).
The combination index (CI) of each different drug-drug combination was calculated by applying the Chou and Talalay method. Different degrees of synergism (CI < 1) were recorded when PM1183 was combined with AZD-2281 (Olaparib) and BMN-673, depending on the tumor cell line and the conditions tested. The highest degree of synergism with Olaparib was observed in MDA-MB-436 cells followed by MDA-MB-231, MCF7 and HCC-1937 cells. The highest degree of synergism with BMN-673 was observed in MCF-7 cells followed by MDA-MB-231 and HCC-1937 cells. In MDA-MB-231 cells, both combinations led to a synergistic induction of γ-H2AX expression and PARP-1 cleavage, as analyzed by western blot. Collectively, our results indicate that the combination of PM1183 and PARP inhibitors (Olaparib and BMN673) induces an artificial synthetic lethality that can be advantageously used to kill several breast cancer cells, independently from their BRCA1 status.