A Link between Benzyl Isothiocyanate-Induced Cell Cycle Arrest and Apoptosis: Involvement of Mitogen-Activated Protein Kinases in the Bcl-2 Phosphorylation

Noriyuki Miyoshi, Koji Uchida, Toshihiko Osawa, Yoshimasa Nakamura

Research output: Contribution to journalArticlepeer-review

124 Citations (Scopus)

Abstract

In the present study, we clarified the molecular mechanism underlying the relationship between benzyl isothiocyanate (BITC)-induced cell cycle arrest and apoptosis and the involvement of mitogen-activated protein kinases (MAPKs). The exposure of Jurkat human T-cell leukemia cells to BITC resulted in the inhibition of the G2-M progression that coincided with the apoptosis induction. The experiment using the phase-specific synchronized cells demonstrated that the G2-M phase-arrested cells are more sensitive to undergoing apoptotic stimulation by BITC than the cells in other phases. We also confirmed that BITC activated c-Jun N-terminal kinase (JNK) and p38 MAPK, but not extracellular signal-regulated kinase, at the concentration required for apoptosis induction. An experiment using a JNK-specific inhibitor SP600125 or a p38 MAPK inhibitor SB202190 indicated that BITC-induced apoptosis might be regulated by the activation of these two kinases. Conversely, BITC is likely to confine the Jurkat cells in the G2-M phase mainly through the p38 MAPK pathway because only the p38 MAPK inhibitor significantly attenuated the accumulation of inactive phosphorylated Cdc2 protein and the G 2M-arrested cell numbers. We reported here for the first time that the antiapoptotic Bcl-2 protein was phosphorylated by the BITC treatment without significant alteration of the Bcl-2 total protein amount. This was abrogated by a JNK specific inhibitor SP600125 at the concentration required for specific inhibition of the c-Jun phosphorylation. Moreover, the spontaneous phosphorylation of antiapoptotic Bcl-2 in the G2-M synchronized cells was enhanced synergistically by the BITC treatment. Involvement of the MAPK activation in the Bcl-2 phosphorylation and apoptosis induction also was observed in HL-60 and HeLa cells. Thus, we identified the phosphorylated Bcl-2 as a key molecule linking the p38 MAPK-dependent cell cycle arrest with the JNK activation by BITC.

Original languageEnglish
Pages (from-to)2134-2142
Number of pages9
JournalCancer Research
Volume64
Issue number6
DOIs
Publication statusPublished - Mar 15 2004
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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