Phenylethyl isothiocyanate induces apoptotic signaling via suppressing phosphatase activity against c-Jun N-terminal kinase.

Abstract

Dietary isothiocyanates induce apoptosis in various cancer cell lines through a c-Jun N-terminal kinase (JNK)-dependent mechanism. We found that phenylethyl isothiocyanate (PEITC) was capable of inducing JNK activation and apoptosis in prostate cancer cell lines with distinct p53 statuses. PEITC induced JNK-mediated apoptotic signaling via a different pathway than that used by DNA-damaging agents, because genotoxicresistant LNCaP prostate cancer cells were equally sensitive to PEITC as parental LNCaP cells. PEITC did not induce significant MKK4 or MKK7 activation and did not activate JNK directly, suggesting that JNK and JNK upstream kinases are not primary targets of PEITC. The JNK dephosphorylation and inactivation rates were decreased in cells exposed to PEITC. Expression levels of M3/6, a JNK-specific phosphatase, were down-regulated by PEITC via a proteasome-dependent mechanism. Taken together, our data suggest that PEITC activates JNK through suppression of JNK dephosphorylation and that PEITC may be an alternative therapeutic agent for cancers that are resistant to genotoxic agents. This study also reveals that JNK phosphatases are potential targets for the development of novel cancer therapeutic agents.

• Authors: Yi-Rong Chen, Jin Han, Rajashree Kori, A-N Tony Kong, Tse-Hua Tan
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 277 Issue 42 Pg. 39334-42 (Oct 18 2002) ISSN: 0021-9258 [Print] United States
• PMID: 12171915 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Isothiocyanates
• Tumor Suppressor Protein p53
• Propidium
• phenethyl isothiocyanate
• Adenosine Triphosphate
• JNK Mitogen-Activated Protein Kinases
• Mitogen-Activated Protein Kinases
• Phosphoric Monoester Hydrolases

Topics

• Adenosine Triphosphate (metabolism)
• Apoptosis
• Blotting, Western
• DNA Fragmentation
• Dose-Response Relationship, Drug
• Dose-Response Relationship, Radiation
• Down-Regulation
• Humans
• Isothiocyanates (pharmacology)
• JNK Mitogen-Activated Protein Kinases
• Male
• Mitogen-Activated Protein Kinases (metabolism)
• Phosphoric Monoester Hydrolases (metabolism)
• Phosphorylation
• Plasmids (metabolism)
• Precipitin Tests
• Propidium (metabolism)
• Prostatic Neoplasms (metabolism)
• Time Factors
• Transfection
• Tumor Cells, Cultured
• Tumor Suppressor Protein p53 (metabolism)