DNA damaging drugs-induced down-regulation of Bcl-2 is essential for induction of apoptosis in high-risk HPV-positive HEp-2 and KB cells.
DNA damaging chemotherapeutic agents like carboplatin (Carb) and 5-fluorouracil (5-FU), whose effects are mediated through diverse intracellular targets, induce apoptosis in various cancer cells including human papillomavirus (HPV) positive HEp-2 and KB cells. The present work reports the involvement of Bcl-2 in response to the exposure of HEp-2 and KB cells to Carb or 5-FU. We demonstrate that both these drugs are potent inducers of apoptosis. Apoptosis was preceded by decrease in Bcl-2 protein level accompanied by caspase-9 activation and poly(ADP-ribose) polymerase (PARP) cleavage without altering Bax expression. Further analysis revealed down-regulation of Bcl-2 mRNA as well as protein in drugs treated cells. Ectopic expression of Bcl-2 protected cells against drugs mediated DNA damage-induced apoptosis. Overall, data indicates that genotoxic stress leads to down-regulation of Bcl-2 in HEp-2 and KB cells, which plays a decisive role in the outcome of stress in these cells.
Singh
Sandeep
S
National Centre for Cell Science, NCCS Complex, Ganeshkhind, Pune 411 007, India.
Chhipa
Rishi Raj
RR
Vijayakumar
Maleppillil Vavachan
MV
Bhat
Manoj Kumar
MK
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D016190:Carboplatin / Q000494:pharmacology*; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation / Q000187:drug effects; D005472:Fluorouracil / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007624:KB Cells; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000188:drug therapy*; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection
D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016190:Carboplatin; D011065:Poly(ADP-ribose) Polymerases; C506433:CASP9 protein, human; D053453:Caspase 9; D020169:Caspases; D005472:Fluorouracil