The role of PKCε in non-small cell lung cancer cells against TRAIL-induced apoptosis

• Main Authors: Yu-Huan, 楊雨寰
• Other Authors: 吳文俊
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/53490136253572997410

碩士 === 中山醫學大學 === 醫學分子毒理學研究所 === 95 === Tumor nercrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent as it selectively kills tumor cells but spares normal cells. Resistance to TRAIL by tumor cells limits its therapeutic use in clinic. TRAIL-induced apoptosis is mediated by binding with death receptors, DR4 and DR5, but the decoy receptors ( DcR1 and DcR2 ) on the surface of tumor cells collapse TRAIL-mediated apoptosis. Recently, several articles have demonstrated that some tumor cell lines exhibit TRAIL-resistance and this resistance may be not associated with decoy receptors. Some reports indicated that PKC activation was an important factor for cell to protect apoptosis from TRAIL. Therefore, we analyzed the sensitivity of nine human non-small lung cancer ( NSCLC) cell lines to TRAIL. We found the expression of PKCε is higher in TRAIL-resistant cell lines (H1355 and H520) than those of in TRAIL-sensitive cell lines (H460 and H358). In order to investigate the role of PKCε in TRAIL-resistant cell lines, we used PKCε siRNA and PKCε shRNA to block PKCε activity, and then observed their effect on TRAIL-induced apoptosis. Knockdown of PKCε expression by siRNA resulted in enhanced sensitivity to TRAIL in H1355 and H520 cell lines. Some references pointed out that PKCε is an oncogene. In this research, we investigated the role of PKCε gene in lung cancer cells. First of all, we found out when used PKCε shRNA to suppress PKCε expression, it would decrease cell growth. According to anchorage-independent growth assay, suppressed PKCε expression would decrease cell transformation. Overexpression of PKCε shRNA was associated with a decrease in Bcl-2 protein level in H1355 cell line, and a decrease in Bcl-xL and Mcl-1 in H520 cell line. Moreover, the similar results were observed in animal tumor model. Thus, our results suggest that PKCε may act upstream of mitochondria and mediate TRAIL resistance via Bcl-2 family in H1355 and H520 cells.