Center of Translational Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China.
Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China.
Oncogene. 2021 Jun;40(22):3826-3844. doi: 10.1038/s41388-021-01812-7. Epub 2021 May 6.
Gastric cancer (GC) is one of the leading causes of human mortality around the world. We have previously shown that Gαi1 (the inhibitory subunit 1 of the heterotrimeric guanine nucleotide-binding protein) recruitment to ligand-activated receptor tyrosine kinases (RTKs) is essential for signaling. Testing its role in GC cancer-promoting functions, we found that Gαi1 is upregulated in human GC, correlating with poor overall survival. In established and primary human GC cells, Gαi1 shRNA (small hairpin RNA) or knockout produced significant anti-GC cell activity, proliferation and migration was inhibited, and apoptosis was activated. Conversely, ectopic Gαi1 overexpression promoted proliferation and migration of GC cells in vitro. By examining the tumor-suppressive miRNA microRNA-200a (miR-200a), we found that miR-200a directly silenced Gαi1 to induce anti-GC cell activity. The expression of miR-200a was downregulated in human GC, correlating with upregulation of a novel miR-200a-targeting long non-coding RNA (LncRNA), PINK1 (PTEN Induced Kinase 1)-AS. RNA immunoprecipitation, RNA-pull down, and RNA fluorescence in situ hybridization assays confirmed that PINK1-AS directly binds to miR-200a. Silencing PINK1-AS in GC cells led to miR-200a accumulation, Gαi1 downregulation, and inhibition of GC cell progression in vitro, whereas PINK1-AS upregulation produced the converse results. Significantly, anti-GC cell activity induced by PINK1-AS shRNA was ameliorated by the expression of miR-200a antisense or the 3'-UTR (untranslated region)-depleted Gαi1. In vivo, the growth of subcutaneous MGC-803 xenografts in nude mice was inhibited by PINK1-AS shRNA, but accelerated by PINK1-AS overexpression. Patient-derived GC xenograft growth in nude mice was largely inhibited after intratumoral injection of PINK1-AS shRNA lentivirus. In conclusion, PINK1-AS promotes Gαi1-driven GC progression by sponging miR-200a.
胃癌（GC）是全球人类死亡的主要原因之一。我们之前已经表明，Gαi1（异三聚体鸟苷酸结合蛋白的抑制亚基 1）与配体激活的受体酪氨酸激酶（RTKs）的募集对于信号转导至关重要。在检测其在促进 GC 癌症功能中的作用时，我们发现 Gαi1 在人 GC 中上调，与整体生存不良相关。在已建立和原发性人 GC 细胞中，Gαi1 shRNA（短发夹 RNA）或敲除产生了显著的抗 GC 细胞活性，抑制了增殖和迁移，并激活了细胞凋亡。相反，外源性 Gαi1 过表达促进了体外 GC 细胞的增殖和迁移。通过检查肿瘤抑制性 microRNA 微 RNA-200a（miR-200a），我们发现 miR-200a 直接沉默 Gαi1 以诱导抗 GC 细胞活性。miR-200a 在人 GC 中的表达下调，与新型 miR-200a 靶向长非编码 RNA（LncRNA）PINK1（PTEN 诱导激酶 1）-AS 的上调相关。RNA 免疫沉淀、RNA 下拉和 RNA 荧光原位杂交实验证实 PINK1-AS 直接与 miR-200a 结合。在 GC 细胞中沉默 PINK1-AS 导致 miR-200a 积累、Gαi1 下调，并抑制体外 GC 细胞进展，而 PINK1-AS 上调则产生相反的结果。重要的是，PINK1-AS shRNA 诱导的抗 GC 细胞活性通过表达 miR-200a 反义或 3'-UTR（非翻译区）耗尽的 Gαi1 得到改善。在体内，裸鼠皮下 MGC-803 异种移植的生长被 PINK1-AS shRNA 抑制，但被 PINK1-AS 过表达加速。裸鼠体内患者来源的 GC 异种移植生长在注射 PINK1-AS shRNA 慢病毒后被极大地抑制。总之，PINK1-AS 通过海绵 miR-200a 促进 Gαi1 驱动的 GC 进展。
