title: Induction and repair of DNA double-strand breaks using constant-field gel electrophoresis and apoptosis as predictive markers for sensitivity of cancer cells to cisplatin.
abstract: This study was designed to evaluate some parameters that may play a role in the prediction of cancer cells sensitivity to cisplatin (CIS). Sensitivity, induction and repair of DNA double-strand breaks (DSB), cell cycle regulation and induction of apoptosis were measured in four cancer cell lines with different sensitivities to CIS. Using a sulphorhodamine-B assay, the cervical carcinoma cells (HeLa) were found to be the most sensitive to CIS followed by breast carcinoma cells (MCF-7) and liver carcinoma cells (HepG2). Colon carcinoma HCT116 cells were the most resistant. As measured by constant-field gel electrophoresis (CFGE), DSB induction, but not residual DSB exhibited a significant correlation with the sensitivity of cells to CIS. Flow cytometric DNA ploidy analysis revealed that 67% of HeLa cells and 10% of MCF-7 cells shift to sub-G1 phase after incubation with CIS. Additionally, CIS induced the arrest of MCF-7 cells in S-phase and the arrest of HepG2 and HCT116 cells in both S phase and G2/M phase. Determination of the Fas-L level and Caspase-9 activity indicated that CIS-induced apoptosis results from the mitochondrial (intrinsic) pathway. These results, if confirmed using clinical samples, indicate that the induction of DNA DSB as measured by CFGE and the induction of apoptosis should be considered, along with other predictive markers, in future clinical trials to develop predictive assays for platinum -based therapy.
authors.affiliation: Clinical Biochemistry and Molecular Biology unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt. ekramsaleh@hotmail.com
authors.forename: Ekram M
authors.initials: EM
authors.lastname: Saleh
authors.forename: Raafat A
authors.initials: RA
authors.lastname: El-Awady
authors.forename: Noha
authors.initials: N
authors.lastname: Anis
authors.forename: Nahla
authors.initials: N
authors.lastname: El-Sharkawy
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053453:Caspase 9 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects*; D004260:DNA Repair; D019008:Drug Resistance, Neoplasm; D004587:Electrophoresis, Agar Gel; D053222:Fas Ligand Protein / Q000378:metabolism; D005434:Flow Cytometry; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D061986:MCF-7 Cells; D008928:Mitochondria / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D053222:Fas Ligand Protein; D053453:Caspase 9; D002945:Cisplatin