Calpeptin suppresses tumor necrosis factor-alpha-induced death and accumulation of p53 in L929 mouse sarcoma cells.
The cytokine tumor necrosis factor (TNF)alpha induces caspase-dependent cell death in a subset of tumor cells. In this report, we show a novel suppressive effect of calpeptin, a calpain inhibitor, on TNFalpha-induced cell death and accumulation of p53 in L929 mouse fibrosarcoma. Exposure to 10 ng/ml TNFalpha induced cell death in >50% of L929 cells within 12 h and stimulated accumulation of p53 (8-fold). Preincubation of cells with calpeptin blocked both TNFalpha-induced cell death and accumulation of p53 as examined with Western blot. TNFalpha-induced accumulation of p53 was in part contributed by increase of p53 mRNA level (2.2-fold) in a calpeptin-insensitive manner. Interestingly, other calpain inhibitors tested did not show these effects like calpeptin and TNFalpha treatment did not increase apparent calpain activity in L929 cells, suggesting that calpeptin may have another function besides targeting calpain. Expression of dominant negative mutant p53Val(135) reduced the incidence of TNFalpha-mediated cell death. Taken together, our findings suggest that TNFalpha induces calpeptin-dependent, but calpain-independent accumulation of p53 protein as a necessary step leading to death in L929 cells.
Kim
B J
BJ
Department of Life Science, Kwangju Institute of Science and Technology, 1 Oryong-dong Puk-gu, Kwangju 500-712, Korea.
Jung
Y K
YK
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002154:Calpain / Q000494:pharmacology; D016923:Cell Death; D002470:Cell Survival; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000737:chemistry / Q000494:pharmacology*; D005799:Genes, Dominant; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D051736:Proto-Oncogene Proteins c-mdm2; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; C071482:calpeptin; D008156:Luciferases; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D002154:Calpain