Dai Zhi-Jun, Gao Jie, Ma Xiao-Bin, Kang Hua-Feng, Wang Bao-Feng, Lu Wang-Feng, Lin Shuai, Wang Xi-Jing, Wu Wen-Ying
Department of Oncology, the Second Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an 710004, China.
Int J Mol Sci. 2012 Dec 21;14(1):273-85. doi: 10.3390/ijms14010273.
Rapamycin (Rapa), an inhibitor of mammalian target of Rapamycin (mTOR), is an immunosuppressive agent that has anti-proliferative effects on some tumors. This study aims to investigate the effects of Rapa suppressing proliferation of pancreatic carcinoma PC-2 cells in vitro and its molecular mechanism involved in antitumor activities. MTT assays showed that the inhibition of proliferation of PC-2 cells in vitro was in a time- and dose-dependent manner. By using transmission electron microscopy, apoptosis bodies and formation of abundant autophagic vacuoles were observed in PC-2 cells after Rapa treatment. Flow cytometry assays also showed Rapa had a positive effect on apoptosis. MDC staining showed that the fluorescent density was higher and the number of MDC-labeled particles in PC-2 cells was greater in the Rapa treatment group than in the control group. RT-PCR revealed that the expression levels of p53, Bax and Beclin 1 were up-regulated in a dose-dependent manner, indicating that Beclin 1 was involved in Rapa induced autophagy and Rapa induced apoptosis as well as p53 up-regulation in PC-2 cells. The results demonstrated that Rapa could effectively inhibit proliferation and induce apoptosis and autophagy in PC-2 cells.
雷帕霉素（Rapa）是哺乳动物雷帕霉素靶蛋白（mTOR）的抑制剂，是一种对某些肿瘤具有抗增殖作用的免疫抑制剂。本研究旨在探讨雷帕霉素体外抑制胰腺癌PC - 2细胞增殖的作用及其抗肿瘤活性的分子机制。MTT法检测结果显示，雷帕霉素体外抑制PC - 2细胞增殖呈时间和剂量依赖性。通过透射电子显微镜观察发现，雷帕霉素处理后的PC - 2细胞中出现凋亡小体和大量自噬空泡。流式细胞术检测结果也表明雷帕霉素对细胞凋亡有促进作用。单丹磺酰尸胺（MDC）染色显示，雷帕霉素处理组PC - 2细胞的荧光密度更高，MDC标记颗粒数量更多。逆转录聚合酶链反应（RT-PCR）结果显示，p53、Bax和Beclin 1的表达水平呈剂量依赖性上调，表明Beclin 1参与了雷帕霉素诱导的PC - 2细胞自噬、凋亡以及p53上调。结果表明，雷帕霉素可有效抑制PC - 2细胞增殖并诱导其凋亡和自噬。
