Arecoline-induced phosphorylated p53 and p21WAF1 protein expression is dependent on ATM/ATR and phosphatidylinositol-3-kinase in clone-9 cells
✍ Scribed by Wen-Wen Chou; Jinn-Yuh Guh; Jung-Fa Tsai; Chi-Ching Hwang; Shean-Jaw Chiou; Lea-Yea Chuang
- Book ID
- 102300948
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 368 KB
- Volume
- 107
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
Betel‐quid use is associated with liver cancer whereas its constituent arecoline is cytotoxic, genotoxic, and induces p53‐dependent p21^WAF1^ protein expression in Clone‐9 cells (rat hepatocytes). The ataxia telangiectasia mutated (ATM)/rad3‐related (ATR)‐p53‐p21^WAF1^ and the phosphatidylinositol‐3‐kinase (PI3K)‐mammalian target of rapamycin (mTOR) pathways are involved in the DNA damage response and the pathogenesis of cancers. Thus, we studied the role of ATM/ATR and PI3K in arecoline‐induced p53 and p21^WAF1^ protein expression in Clone‐9 cells. We found that arecoline (0.5 mM) activated the ATM/ATR kinase at 30 min. The arecoline‐activated ATM/ATR substrate contained p‐p53Ser15. Moreover, arecoline only increased the levels of the p‐p53Ser6, p‐p53Ser15, and p‐p53Ser392 phosphorylated p53 isoforms among the known isoforms. ATM shRNA attenuated arecoline‐induced p‐p53Ser15 and p21^WAF1^ at 24 h. Arecoline (0.5 mM) increased phosphorylation levels of p‐AktSer473 and p‐mTORSer2448 at 30–60 min. Dominant‐negative PI3K plasmids attenuated arecoline‐induced p21^WAF1^, but not p‐p53Ser15, at 24 h. Rapamycin attenuated arecoline‐induced phosphrylated p‐p53Ser15, but not p21^WAF1^, at 24 h. ATM shRNA, but not dominant‐negative PI3K plasmids, attenuated arecoline‐induced p21^WAF1^ gene transcription. We conclude that arecoline activates the ATM/ATR‐p53‐p21^WAF1^ and the PI3K/Akt‐mTOR‐p53 pathways in Clone‐9 cells. Arecoline‐induced phosphorylated p‐p53Ser15 expression is dependent on ATM whereas arecoline‐induced p21^WAF1^ protein expression is dependent on ATM and PI3K. Moreover, p21^WAF1^ gene is transcriptionally induced by arecoline‐activated ATM. J. Cell. Biochem. 107: 408–417, 2009. © 2009 Wiley‐Liss, Inc.