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Inhibition of the growth of WI-38 fibroblasts by benzyloxycarbonyl-Leu-Leu-Tyr diazomethyl ketone: evidence that cleavage of p53 by a calpain-like protease is necessary for G1 to S-phase transition
- Source :
- Oncogene. 14:255-263
- Publication Year :
- 1997
- Publisher :
- Springer Science and Business Media LLC, 1997.
-
Abstract
- The effect of a calpain-selective cell permeant inhibitor, benzyloxycarbonyl Leu-Leu-Tyr diazomethylketone (ZLLY-CHN2), on the serum-stimulated growth of WI-38 human fibroblasts has been investigated. Only cell permeant protease inhibitors with activity against calpains prevented progression into S-phase. Protein blotting experiments indicated that p53 immunoreactivity increased in late G1 cells treated with ZLLY-CHN2. The content of p21Waf1/Cip1 CDK inhibitor also increased, providing a mechanism for the observed failure to enter S-phase. Further studies indicated that p53 could be degraded by a ZLLY-CHN2-sensitive protease immediately prior to S-phase, but that proteolysis did not occur after this critical time point. Chelation of extracellular Ca2+ by addition of EGTA inhibited the p53 degradation. Consistent with proteolysis of p53 in late G1 phase, mu-calpain immunoreactivity transiently accumulated in cell nuclei at this time. ZLLY-CHN2 did not appear to increase p53 mRNA in WI-38 cells. Purified mu-calpain required only 1 to 3 microM Ca2+ to proteolyze p53 in WI-38 cell lysates. These results indicate that ZLLY-CHN2 inhibits progression of WI-38 cells into S-phase by inactivating a calpain-like protease that is responsible for proteolysis of constitutively expressed p53 in late G1.
- Subjects :
- Cancer Research
Proto-Oncogene Proteins c-jun
Proteolysis
medicine.medical_treatment
Cysteine Proteinase Inhibitors
S Phase
Genetics
Extracellular
medicine
Humans
Fibroblast
Egtazic Acid
Molecular Biology
Cell Nucleus
Protease
biology
medicine.diagnostic_test
Calpain
Cell growth
G1 Phase
Fibroblasts
Molecular biology
medicine.anatomical_structure
Diazomethane
Biochemistry
Cell culture
biology.protein
Calcium
Tumor Suppressor Protein p53
Oligopeptides
CDK inhibitor
Subjects
Details
- ISSN :
- 14765594 and 09509232
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Oncogene
- Accession number :
- edsair.doi.dedup.....4b7575d8ca738d2178b59d2da5b929ee