Sensitization by wortmannin of heat- or X-ray induced cell death in cultured Chinese hamster V79 cells.
Here we found that wortmannin sensitized Chinese hamster V79 cells to hyperthermic treatment at 44.0 degrees C as determined either by colony formation assay or by dye exclusion assay. Wortmannin enhanced heat-induced cell death accompanying cleavage of poly (ADP-ribose) polymerases (PARP). Additionally, the induction of heat shock protein HSP70 was suppressed and delayed in wortmannin-treated cells. Heat sensitizing effect of wortmannin was obvious at more than 5 or 10 microM of final concentrations, while radiosensitization was apparent at 5 microM. Requirement for high concentration of wortmannin, i.e., order of microM, suggests a possible role of certain protein kinases, such as DNA-PK and/or ATM among PI3-kinase family. The sensitization was minimal when wortmannin was added at the end of heat treatment. This was similar to the case of X-ray. Since heat-induced cell death and PARP cleavage preceded HSP70 induction phenomenon, the sensitization to the hyperthermic treatment was considered mainly caused by enhanced apoptotic cell death rather than secondary to suppression or delay by wortmannin of HSP70 induction. Further, in the present system radiosensitization by wortmannin was also at least partly mediated through enhancement of apoptotic cell death.
Tomita
M
M
Department of Radiation Oncology, Graduate School of Medicine, University of Tokyo, Japan.
Suzuki
N
N
Matsumoto
Y
Y
Hirano
K
K
Umeda
N
N
Sakai
K
K
D000730:Androstadienes / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D018797:Cell Cycle Proteins; D002470:Cell Survival; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D003114:Colony-Forming Units Assay; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair / Q000187:drug effects; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000187:drug effects; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature; D008168:Lung; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins; D000077191:Wortmannin
D000730:Androstadienes; D064007:Ataxia Telangiectasia Mutated Proteins; D020169:Caspases; D018797:Cell Cycle Proteins; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011065:Poly(ADP-ribose) Polymerases; D017346:Protein Serine-Threonine Kinases; D011838:Radiation-Sensitizing Agents; D025521:Tumor Suppressor Proteins; D000077191:Wortmannin