Department of Gastroenterology, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
J Gastrointest Surg. 2010 Aug;14(8):1227-34. doi: 10.1007/s11605-010-1253-4. Epub 2010 Jun 11.
The aim of this study was to investigate the role of Mad1/c-Myc in telomerase regulation in gastric cancer cells in order to gain insight into telomerase activity and to evaluate PinX1 as a putative inhibitor of gastric cancer.
PinX1 and PinX1siRNA eukaryotic expression vectors were constructed by recombinant technology and transfected into gastric carcinoma cells using Lipofectamine 2000. Telomerase activity was measured by the telomeric repeat amplification protocol. Apoptosis of gastric cancer cells was analyzed by flow cytometry and transmission electron microscopy. Reverse transcription-polymerase chain reaction and Western blotting were used to assess the expression levels of PinX1 and Mad1/c-Myc.
We found that PinX1-negative gastric cancer cells showed significantly higher telomerase activity than did the PinX1-postive cells. PinX1-transfection reduced telomerase activity in PinX1-negative gastric cancer cells and exhibited an upregulation of Mad1 and downregulation of c-Myc expression. Pinx1 RNAi treatment led to downregulation of Mad1 and upregulation of c-Myc.
Suppression of telomerase activity mediated by PinX1 is involved in the Mad1/c-Myc pathway.
本研究旨在探讨 Mad1/c-Myc 在胃癌细胞端粒酶调控中的作用，以期深入了解端粒酶活性，并评估 PinX1 作为一种潜在的胃癌抑制剂。
采用重组技术构建 PinX1 和 PinX1siRNA 真核表达载体，用 Lipofectamine 2000 将其转染入胃癌细胞。采用端粒重复扩增协议测定端粒酶活性。通过流式细胞术和透射电镜分析胃癌细胞的凋亡。采用反转录-聚合酶链反应和 Western blot 检测 PinX1 和 Mad1/c-Myc 的表达水平。
我们发现 PinX1 阴性胃癌细胞的端粒酶活性明显高于 PinX1 阳性细胞。PinX1 转染降低了 PinX1 阴性胃癌细胞的端粒酶活性，并表现出 Mad1 的上调和 c-Myc 的下调。Pinx1 RNAi 处理导致 Mad1 的下调和 c-Myc 的上调。
PinX1 介导的端粒酶活性抑制涉及 Mad1/c-Myc 通路。
