Synergistic Effect of Trabectedin and Olaparib Combination Regimen in Breast Cancer Cell Lines / 한국유방암학회지

PURPOSE: Trabectedin induces synthetic lethality in tumor cells carrying defects in homologous recombinant DNA repair. We evaluated the effect of concomitant inhibition of nucleotide-excision repair and poly (ADP-ribose) polymerase (PARP) activity with trabectedin and PARP inhibitors, respectively, and whether the synthetic lethality effect had the potential for a synergistic effect in breast cancer cell lines. Additionally, we investigated if this approach remained effective in BRCA1-positive breast tumor cells. METHODS: We have evaluated the in vitro synergistic effect of combinations of trabectedin and three different PARP inhibitors (veliparib, olaparib, and iniparib) in four breast cancer cell lines, each presenting a different BRCA1 genetic background. Antiproliferative activity, DNA damage, cell cycle perturbations and poly(ADP-ribosyl)ation were assessed by MTT assay, comet assay, flow cytometry and western blot, respectively. RESULTS: The combination of trabectedin and olaparib was synergistic in all the breast cancer cell lines tested. Our data indicated that the synergy persisted regardless of the BRCA1 status of the tumor cells. Combination treatment was associated with a strong accumulation of double-stranded DNA breaks, G2/M arrest, and apoptotic cell death. Synergistic effects were not observed when trabectedin was combined with veliparib or iniparib. CONCLUSION: Collectively, our results indicate that the combination of trabectedin and olaparib induces an artificial synthetic lethality effect that can be used to kill breast cancer cells, independent of BRCA1 status.

Chemotherapy in adult soft tissue sarcoma.

Soft tissue sarcomas (STSs) are rare and histologically diverse neoplasms. Recent results of various meta-analyses and development of newer drugs have changed the medical management of soft tissue sarcoma. This review gives an outline of chemotherapy and the newer targeted therapies for the same. We have carried out an extensive search in PubMed, Medline for almost all relevant articles concerning chemotherapy of soft tissue sarcoma. The available data from the literature is mainly composed of the most recent reviews, meta-analyses, phase II, and randomized phase III trials published in various peer reviewed journals and various international conferences. The role of neoadjuvant and adjuvant chemotherapy has been found to be controversial. The recent meta-analysis for adjuvant therapy in STSs has shown an increase in the overall survival with combination of ifosfamide and adriamycin. In locally advanced and metastatic STSs, single agent adriamycin remains the basic standard of medication. The combination of ifosfamide and adriamycin may also be used for rapid symptom relief and in patients planned for curative resection for metastases. Newer combinations of docetaxel and gemcitabine appear promising in selected subgroups, especially in leiomyosarcoma and malignant fibrous histiocytoma. Some recent developments include the European Union's approval of trabectedin for advanced STSs patients who had progressed on adriamycin and ifosfamide therapy. The future of mTOR inhibitors, insulin like growth factor receptor inhibitors and anti-angiogenic drugs appear quite promising. Newer methodologies such as, Bayesian adaptive randomization and inclusion of newer end points like progression-free rate, time of progression rate, and tumor growth rate will improve the results of sarcoma trials. At the end of each section we have also presented recommendations from *European Society of Medical Oncology and **National Comprehensive Cancer Network guidelines v.1.2009 for better correlation with the present literature.