title: Suppression of apoptosis leads to cisplatin resistance in V79 cells subjected to chronic oxidative stress.
abstract: We derived V79(C) cells from V79 cell line through chronic oxidative stress by H2O2. These cells demonstrated transformation-like stable changes. Our objective was to see how V79(C) cells would respond to cisplatin treatment and also to understand the mechanism of cisplatin-resistance, because resistance towards various chemotherapeutic agents is major cause of concern in cancer therapeutics. The sensitivity to cisplatin in these cells was observed by comparing the viability with that of parental V79 cells from colonogenic assay. The role of apoptotic death was investigated microscopically by Hoechst staining and from nucleosomal ladder formation in agarose gel. Release of cytochrome c from the mitochondria was determined by Western blotting. Caspase 9 and caspase 3 activities were estimated through fluorimetric assay. We found that V79(C) cells exhibited lower sensitivity towards killing by cisplatin through suppression of apoptotic cell death. Quantifying the release of cytochrome c in the cytoplasm and assay of caspase 9 and caspase 3 activities revealed that cisplatin resistance was due to inhibition of caspase-dependent apoptotic death pathways. These findings may aid in understanding the mechanism of cisplatin resistance in tumors arising from oxidative stress. Exogenous caspases may facilitate apoptotic death to sensitize such resistant cells.
authors.affiliation: Department of Biochemistry and Biophysics, University of Kalyani, Kalyani-741235, West Bengal, India. ritadg2001@yahoo.co.in
authors.forename: Rita
authors.initials: R
authors.lastname: Ghosh
authors.forename: Koyeli
authors.initials: K
authors.lastname: Girigoswami
authors.forename: Guha
authors.initials: G
authors.lastname: Dipanjan
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology*; D004351:Drug Resistance / Q000187:drug effects / Q000502:physiology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology*
chemical_list: D002945:Cisplatin