Bcl-2 cleavages at two adjacent sites by different caspases promote cisplatin-induced apoptosis

Cell Res. 2007 May;17(5):441-8. doi: 10.1038/cr.2007.36.

Abstract

The protein encoded by bcl-2 proto-oncogene plays an important role in the mitochondria-mediated apoptotic pathway. Although the general role of Bcl-2 is anti-apoptotic, previous work showed that Bcl-2 fragments cleaved by caspases could promote apoptotic process. We report herein that Bcl-2 protein was cleaved to produce two fragments of around 23 kDa in human hepatocarcinoma BEL-7404 cells or in Bcl-2 overexpressing CHO cells induced by cisplatin. Treating cells with the general caspase inhibitor z-VAD-fmk blocked the induced cleavage of Bcl-2. Mutagenesis analyses showed that Bcl-2 was cleaved by caspases at two adjacent recognition sites in the loop domain (YEWD(31) decrease AGD(34) decrease V), which could be inhibited by caspase-8 and -3 inhibitors, respectively. Overexpression of the carboxyl terminal 23 kDa fragments increased the sensitivity of CHO cells to cisplatin-induced apoptosis. These results indicate that Bcl-2 can be cleaved into two close fragments by different caspases during cisplatin-induced apoptosis, both of which contribute to the acceleration of apoptotic process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Amino Acid Sequence
  • Animals
  • Apoptosis / drug effects*
  • CHO Cells
  • Caspase 3 / metabolism*
  • Caspase 8 / metabolism*
  • Caspase Inhibitors
  • Cisplatin / pharmacology*
  • Cricetinae
  • Cricetulus
  • Humans
  • Peptide Fragments / pharmacology
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Proto-Oncogene Proteins c-bcl-2 / pharmacology*
  • Tumor Cells, Cultured

Substances

  • Amino Acid Chloromethyl Ketones
  • Caspase Inhibitors
  • MAS1 protein, human
  • Peptide Fragments
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-bcl-2
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • Caspase 3
  • Caspase 8
  • Cisplatin