Chemotherapeutic agent CPT-11 induces the new expression of the apoptosis initiator to the cytoplasm.
CPT-11, a derivative of camptothecin, induced apoptotic cell death characterized by chromosomal DNA fragmentation in human hepatoma PLC cells in vitro. Cell viability of PLC cells was significantly decreased by CPT-11 in a dose-dependent manner, and CPT-11-induced cytotoxic activity was completely prevented by an interleukin-1 beta converting enzyme-like protease inhibitor YVAD and a protein synthesis inhibitor cycloheximide. To examine the roles of the cytoplasm and the nucleus in CPT-11-induced apoptosis, we prepared cytoplasts from PLC cells and nuclei from rat hepatocytes (RHN). Apoptotic cell death as characterized by cell fragmentation was observed in whole PLC cells but not in PLC cytoplasts after incubation with CPT-11. In addition, CPT-11 could not induce chromosomal DNA fragmentation in RHN. In contrast, the extracts of CPT-11-treated PLC cells, which mainly contained cytosol proteins, induced chromosomal DNA fragmentation of RHN in a dose-dependent manner. These results indicate that CPT-11-induced apoptosis required the presence of both the cytoplasm and the nucleus and suggest that the apoptosis required the de novo synthesis of an apoptosis initiator.
Suzuki
A
A
Drug Safety Research Laboratory, Daiichi Pharmaceutical Co. Ltd., Tokyo, Japan.
Kato
M
M
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular; D020170:Caspase 1; D002457:Cell Extracts; D002467:Cell Nucleus / Q000502:physiology; D003513:Cycloheximide / Q000494:pharmacology; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003593:Cytoplasm / Q000502:physiology*; D004247:DNA / Q000032:analysis; D003609:Dactinomycin / Q000494:pharmacology; D006801:Humans; D000077146:Irinotecan; D008099:Liver / Q000166:cytology; D008113:Liver Neoplasms; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D014407:Tumor Cells, Cultured
D002457:Cell Extracts; D015853:Cysteine Proteinase Inhibitors; D009842:Oligopeptides; D011500:Protein Synthesis Inhibitors; C096429:L 709049; D003609:Dactinomycin; D000077146:Irinotecan; D004247:DNA; D003513:Cycloheximide; D003546:Cysteine Endopeptidases; D020170:Caspase 1; D002166:Camptothecin