长链非编码RNA RAB1A-2在胃癌中的表达及作用

背景与目的:长链非编码RNA(lncRNA)参与细胞增殖、凋亡、周期控制、细胞发育和分化等一系列生物学过程,其差异表达与肿瘤的发生,发展密切相关。lncRNA RAB1A-2(RAB1A-2)一种mTORC1激活剂,目前发现RAB1A-2与肺癌细胞DNA异常扩增、细胞增殖及侵袭有关。为进一步研究其生物学功能,本研究探讨RAB1A-2在胃癌中的表达及作用。方法:采用qRT-PCR法检测68例胃癌组织及癌旁组织﹑3种胃癌细胞系(MKN-45、BGC-823、SGC-7901)及正常胃黏膜细胞系(GES-1)中RAB1A-2的表达,分析RAB1A-2的表达与患者临床病理因素间的关系,Kaplan-Meier生存分析比较RAB1A-2的表达与预后的关系。将SGC-7901细胞系分别转染si-RAB1A-2(RAB1A-2干扰组)、RAB1A-2模拟物(RAB1A-2模拟物组)和阴性对照序列(阴性对照组),分别用MTT法、流式细胞术、Transwell实验检测细胞增殖、凋亡和细胞侵袭能力。结果:qRT-PCR结果显示,胃癌组织中RAB1A-2相对表达量高于癌旁组织,3种胃癌细胞系中RAB1A-2表达量均高于正常胃黏膜细胞系(均P0.05)。胃癌组织中RAB1A-2的表达与肿瘤大小、T分类、N分类和TNM分期均有关(均P0.05)。生存分析结果显示,RAB1A-2高表达患者3、5年总生存率均低于RAB1A-2低表达患者(均P0.05)。与阴性对照组SGC-7901细胞比较,转染后24、48、72 h,RAB1A-2模拟物组SGC-7901细胞的A_(450) nm值均明显升高,RAB1A-2干扰组SGC-7901细胞的A_(450) nm值均明显降低(均P0.05);RAB1A-2模拟物组SGC-7901细胞的凋亡率明显降低,RAB1A-2干扰组SGC-7901细胞的明显升高(均P0.05);RAB1A-2模拟物组SGC-7901细胞的侵袭细胞数明显增加,RAB1A-2干扰组SGC-7901细胞的侵袭细胞数明显减少(均P0.05)。结论:RAB1A-2在胃癌组织和细胞中表达上调,RAB1A-2可促进胃癌细胞增殖和侵袭,并抑制细胞凋亡,RAB1A-2高表达患者预后较差。

Expression of long non-coding RNA RAB1A-2 in gastric cancer and its function

Background and Aims: Long non-coding RNAs (lncRNAs) participate in a series of biological process such as cell proliferation, apoptosis, cell cycle control, cell development and differentiation, and their differential expressions are closely related to the occurrence and development of tumors. LncRNA RAB1A-2 (RAB1A-2) is an activator for MTORC1, and was found to be attributed to aberrant DNA amplification, cell proliferation and invasion in lung cancer cells. For further understand its biological functions, this study was conducted to investigate the expression and function of RAB1A-2 in gastric cancer. Methods: The expressions of RAB1A-2 in 68 pairs of gastric cancer samples along with their adjacent noncancerous tissues, as well as in three gastric cancer cell lines (MKN-45, BGC-823, SGC-7901) and normal gastric mucosa cell line (GES-1) were detected by qRT-PCR. The relations of the expression of RAB1A-2 with clinicopathologic factors of gastric cancer patients were analyzed. The relationship between the expression of RAB1A-2 and prognosis was determined by Kaplan-Meier survival analysis. Gastric cancer SGC-7901 cells were transfected with si-RAB1A-2 (RAB1A-2 interference group), RAB1A-2 mimics (RAB1A-2 mimics group) and negative control sequences (negative control group), respectively. Then, the cell proliferation, apoptosis, and cell invasion ability were tested by MTT assay, flow cytometry, and Transwell assay, respectively. Results: The results of qRT-PCR showed that expression levels of RAB1A-2 in gastric cancer tissue was significantly higher than that in adjacent noncancerous tissues, and in the three gastric cancer cell lines were significantly higher than that in normal gastric mucosa cell line (all P<0.05). The expression of RAB1A-2 was significantly associated with tumor size, T classification, N classification and TNM stage (all P<0.05). Survival analysis showed that both 3- and 5-year overall survival rates in patients with high RAB1A-2 expression were lower than those in patients with low RAB1A-2 expression group (both P<0.05). Compared with the SGC-7901 cells in negative control group, the A450 nm values at 24, 48 and 72 h after transfection were significantly increased in the SGC-7901 cells in RAB1A-2 mimics group, and were significantly decreased in the SGC-7901 cells in RAB1A-2 interference group (all P<0.05); the apoptosis rate was significantly reduced in the SGC-7901 cells in RAB1A-2 mimics group and was significantly increased in the SGC-7901 cells in RAB1A-2 interference group (both P<0.05);  the number of invading cells was significantly increased in the SGC-7901 cells in RAB1A-2 mimics group and was significantly reduced in the SGC-7901 cells in RAB1A-2 interference group (both P<0.05). Conclusion: RAB1A-2 expression is up-regulated in gastric cancer tissue and cells, and RAB1A-2 can promote the proliferation and invasion of gastric cancer cells and inhibit apoptosis. The gastric cancer patients with high RAB1A-2 expression may face a poor prognosis.