Department of General Surgery, Nanyang First People's Hospital, Nanyang, 473012, China.
Department of General Surgery, Nanyang First People's Hospital, Nanyang, 473012, China.
Arch Biochem Biophys. 2020 May 30;685:108352. doi: 10.1016/j.abb.2020.108352. Epub 2020 Mar 30.
Rab1A, a member of the Ras-like protein in rat brain (Rab) family, acts as an oncogene in a variety of malignant tumors. Previous studies reported that Rab1A was highly expressed in GC tissues. However, the function and molecular mechanism of Rab1A in gastric cancer (GC) development remain far from being addressed. Rab1A mRNA and protein levels were detected by qRT-PCR and western blot, respectively. Cell proliferation was evaluated by CCK-8 and BrdU incorporation assays. Apoptosis was estimated by flow cytometry analysis and western blot analysis of B cell lymphoma 2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), Bcl-2 associated X (Bax), and Bcl-2 homologous antagonist/killer (Bak) expression. Alteration of the mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6K) signaling pathway was detected by western blot. We found that Rab1A expression at both mRNA and protein was upregulated in GC cells. Rab1A knockdown significantly inhibited cell proliferation and induced apoptosis in GC cells. Rab1A overexpression promoted proliferation, inhibited cisplatin-induced apoptosis, and increased xenograft growth. In addition, we found that Rab1A knockdown suppressed the mTOR/p70S6K pathway in GC cells. Moreover, activation of mTOR/p70S6K pathway by MHY1485 abolished the effects of Rab1A knockdown on cell proliferation and apoptosis. In conclusion, Rab1A knockdown repressed proliferation and promoted apoptosis in GC cells by inhibition of the mTOR/p70S6K pathway.
Rab1A，一种大鼠脑 Ras 样蛋白（Rab）家族成员，在多种恶性肿瘤中作为癌基因发挥作用。先前的研究报道 Rab1A 在 GC 组织中高度表达。然而，Rab1A 在胃癌（GC）发展中的功能和分子机制仍远未得到解决。通过 qRT-PCR 和 Western blot 分别检测 Rab1A mRNA 和蛋白水平。通过 CCK-8 和 BrdU 掺入测定评估细胞增殖。通过流式细胞术分析和 B 细胞淋巴瘤 2（Bcl-2）、髓样细胞白血病 1（Mcl-1）、Bcl-2 相关 X（Bax）和 Bcl-2 同源拮抗剂/杀伤（Bak）表达的 Western blot 分析评估细胞凋亡。通过 Western blot 检测哺乳动物雷帕霉素靶蛋白（mTOR）/p70 核糖体蛋白 S6 激酶（p70S6K）信号通路的改变。我们发现 Rab1A 在 GC 细胞中的 mRNA 和蛋白水平均上调。Rab1A 敲低显著抑制 GC 细胞的增殖并诱导细胞凋亡。Rab1A 过表达促进增殖，抑制顺铂诱导的凋亡，并增加异种移植瘤的生长。此外，我们发现 Rab1A 敲低抑制了 GC 细胞中的 mTOR/p70S6K 通路。此外，MHY1485 激活 mTOR/p70S6K 通路消除了 Rab1A 敲低对细胞增殖和凋亡的影响。总之，Rab1A 敲低通过抑制 mTOR/p70S6K 通路抑制 GC 细胞的增殖并促进凋亡。
