Inhibition of EZH2 via activation of SAPK/JNK and reduction of p65 and DNMT1 as a novel mechanism in inhibition of human lung cancer cells by polyphyllin I

摘要: Polyphyllin I (PPI), a bioactive phytochemical extracted from the Rhizoma of Paris polyphylla, has been reported to exhibit anti-cancer activity. However, detailed mechanism underlying this remains be elucidated. Cell viability and cell cycle distribution were measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) flow cytometry assays, respectively. The expression enhancer zeste homolog 2 (EZH2) mRNA was by quantitative real time PCR (qRT-PCR). Western blot analysis performed examine phosphorylation protein stress-activated kinase/c-Jun N-terminal kinase (SAPK/JNK), p65, DNA methyltransferase 1 (DNMT1) EZH2. Exogenous DNMT1, EZH2 carried out transient transfection assays. Promoter activity gene determined Secrete-Pair Dual Luminescence Assay Kit. A xenografted tumor model in nude mice bioluminescent imaging system used further test effect PPI vivo. We showed that significantly inhibited growth induced arrest non-small lung cancer (NSCLC) cells dose-dependent manner. Mechanistically, we found increased SAPK/JNK, reduced p65 DNMT1. inhibitor SAPK/JNK (SP600125) blocked PPI-inhibited DNMT1 expression. Interestingly, exogenously expressed overcame Moreover, protein, mRNA, promoter activity; overexpression resisted growth, intriguingly, negative feedback regulation signaling. Finally, exogenous antagonized PPI-suppressed Consistent with this, levels EZH2, vivo. Our results show inhibits NSCLC through SAPK/JNK-mediated inhibition levels, subsequently; reduction interactions among converge on overall responses PPI. This study reveals novel for regulating response suggests new strategy associated therapy.