摘要
背景与目的:Bmi-1(B-cell specific moloneymurine leukemiavirus insertion site 1)基因是多梳基因家族的重要成员之一,主要通过调控INK4a/ARF位点来调节细胞的增殖和衰老。本研究旨在探讨Bmi-1-siRNA对具有INK4a/ARF位点的肺腺癌SPC-A1细胞生长和增殖的影响,并探讨其作用机制。方法:①本实验选用已确定有效的siRNA序列进行病毒包装,构建反转录病毒si-Bmi-1 pSUPERretro-neo,然后感染到SPC-A1细胞中,建立稳定表达Bmi-1-siRNA的肺癌细胞株。②利用RT-PCR和蛋白质印迹法(Western blot)技术分析Bmi-1基因在Bmi-1-siRNA转染后SPC-A1细胞中表达情况。③利用台盼蓝拒染法、MTT法、平板克隆形成实验和裸鼠实验,分析Bmi-1-siRNA对SPC-A1细胞体内外增殖能力的影响。④利用流式细胞术分析SPC-A1各组细胞的周期分布。⑤利用Western blot法分析增殖通路相关分子:p16INK4a、p53、Cyclin D1、PTEN和Ser473p-Akt等蛋白表达情况。结果:反转录病毒介导的Bmi-1-siRNA被转染后,有效抑制了SPC-A1细胞中Bmi-1基因的转录和表达,抑制了SPC-A1细胞的体内外增殖能力(P<0.01),并使转染组细胞阻滞在G1期[(64.6±1.2)%,P<0.05]。沉默Bmi-1基因后,与对照组细胞相比,p16INK4a、p53和Akt蛋白表达水平无明显变化(P>0.05),Cyclin D1和Ser473p-Akt表达水平下降(P<0.01),PTEN表达水平上调(P<0.01)。用PTEN抑制剂处理转染组细胞后,Bmi-1和Ser473p-Akt蛋白表达得以重塑。结论:Bmi-1-siRNA通过将肺腺癌SPC-A1细胞周期阻滞于G1期来抑制肿瘤细胞增殖,这种抑制作用可能不依赖于p16INK4a来调控Cyclin D1的表达,进而参与调控肿瘤细胞增殖。
Background and purpose：The human oncogene B-cell-speciifc moloney murine leukemia virus integration site 1 （Bmi-1） is an important member of the polycomb group family, and it regulates cell proliferation and senescence via INK4a/ARF locus. This study investigated the effects of Bmi-1-siRNA on the proliferation of lung adenocarcinoma cell line SPC-A1 cells with INK4a/ARF locus and clarify the mechanism of Bmi-1-mediated effect on proliferation of lung adenocarcinoma cells. Methods：In this study, we chose the most efifcient siRNA chain the pGeneshl-2-Bmi-1 sense-1 and inserted into a pSUPER-retro-neo retroviral vector. The packaged si-Bmi-1 pSUPERret-ro-neo retroviral vector was stably transfected into lung adenocarcinoma SPC-A1 cell line. The stably transfected cells were cultured and passed. After transfection, the levels of Bmi-1 mRNA and protein expression of SPC-A1 cells were analyzed by RT-PCR and Western blot respectively. Trypan blue, MTT and plate colony forming assay were performed to observe the proliferation capibility of SPC-A1 cells and evaluate the cloning forming ability in vitro. The potency of tumorigenesis was observed in nude mouse through hypodermic inoculation of SPC-A1 cells. Cell cycle distribution was analyzed by lfow cytometry （FCM） in SPC-A1 cells. The expression levels of proliferation proteins including p16^INK4a, p53, Cyclin D1, PTEN, Akt and Ser473p-Akt were analyzed by Western blot. Results：The mRNA and protein expression levels of Bmi-1 were signiifcantly reduced in SPC-A1-Bmi-1-siRNA cells transfected with pSUPER-retro-neo retroviral vector. Knockdown of Bmi-1 could inhibit the growth, colony formation in vitro and tumorigenesis in vivo of SPC-A1 cells （P〈0.01）. The transfected SPC-A1 cells were arrested in G1 phase [（64.6±1.2）%, P〈0.05]. Compared with two control groups, p16^INK4a, p53 and Akt were not affected （P〉0.05）, while Cyclin D1 and Ser473p-Akt were downregulated （P〈0.01） and PTEN was up-regulated （P〈0.01） in the SPC-A1-Bmi-1-si
出处
《中国癌症杂志》
CAS
CSCD
北大核心
2014年第5期333-341,共9页
China Oncology
基金
辽宁省科技厅自然科学基金项目(No:20072169)
