Su Rui, Zhang Jun
Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Department of Gastrointestinal Surgery, Affiliated Hospital of Chengde Medical College, Chengde, Hebei 067000, P.R. China.
Exp Ther Med. 2020 Jul;20(1):646-654. doi: 10.3892/etm.2020.8672. Epub 2020 Apr 22.
LYN kinase (LYN) is a member of the Src tyrosine kinase family, which plays an important role in multiple tumor-related functions. The current study demonstrated that LYN functions as a pro-oncogene in AGS gastric cancer cells. It was found that LYN expression levels were significantly raised in gastric cancer tissue and were significantly associated with the pathological grades of patients with gastric cancer. This was accomplished by knocking down LYN in AGS cells using short hairpin RNA (shRNA) plasmid transfection, with reverse transcription-quantitative PCR detection verifying the effectiveness of RNA interference. It was found that the cell proliferation and colony formation abilities of AGS cells were significantly inhibited, using CCK-8 and clone formation assays, respectively. Furthermore, LYN knockdown was found to induce apoptosis and inhibit both migration and invasion in AGS cells, using flow cytometry and Transwell assays, respectively. A mechanical investigation further suggested that LYN knockdown resulted in the activation of the mitochondrial apoptotic pathway. Likewise, the Wnt/β-catenin pathway was inactivated by LYN knockdown, including decreased levels of Wnt3a, β-catenin, snail family transcriptional repressor (Snail)1 and Snail2. Epithelial-mesenchymal transition mesenchymal markers (including N-cadherin and vimentin) were also found to be downregulated, and E-cadherin was upregulated in LYN-silenced AGS cells. Finally, the AKT/mTOR pathway was found to be downregulated by LYN knockdown in AGS cells, including decreased levels of phosphorylated (p)-AKT (Ser473), p-mTOR (Ser2448), and the down-stream effector p70S6 kinase (p70S6K). Furthermore, the AKT pathway activator, insulin like growth factor-1 (IGF-1), was found to reverse the inhibitory effects of LYN knockdown on the proliferation, migration and invasion of AGS cells. In conclusion, the current study demonstrated that LYN plays an oncogenic role in the proliferation, survival and movement of human gastric cancer cells by activating the mitochondrial apoptotic pathway, and downregulating the Wnt/β-catenin and AKT/mTOR pathways. The current research provides a comprehensive insight into the regulation of LYN in gastric cancer and may help with the development of new tumor treatment strategies.
LYN激酶（LYN）是Src酪氨酸激酶家族的成员，在多种肿瘤相关功能中发挥重要作用。当前研究表明，LYN在AGS胃癌细胞中作为原癌基因发挥作用。研究发现，LYN在胃癌组织中的表达水平显著升高，且与胃癌患者的病理分级显著相关。这是通过使用短发夹RNA（shRNA）质粒转染敲低AGS细胞中的LYN来实现的，逆转录定量PCR检测验证了RNA干扰的有效性。分别使用CCK-8和克隆形成试验发现，AGS细胞的细胞增殖和集落形成能力受到显著抑制。此外，分别使用流式细胞术和Transwell试验发现，敲低LYN可诱导AGS细胞凋亡，并抑制其迁移和侵袭。一项机制研究进一步表明，敲低LYN会导致线粒体凋亡途径的激活。同样，敲低LYN会使Wnt/β-连环蛋白途径失活，包括Wnt3a、β-连环蛋白、蜗牛家族转录抑制因子（Snail）1和Snail2水平降低。在LYN沉默的AGS细胞中，还发现上皮-间质转化间充质标志物（包括N-钙黏蛋白和波形蛋白）下调，而E-钙黏蛋白上调。最后，发现敲低LYN会使AGS细胞中的AKT/mTOR途径下调，包括磷酸化（p）-AKT（Ser473）、p-mTOR（Ser2448）和下游效应物p70S6激酶（p70S6K）水平降低。此外，发现AKT途径激活剂胰岛素样生长因子-1（IGF-1）可逆转敲低LYN对AGS细胞增殖、迁移和侵袭的抑制作用。总之，当前研究表明，LYN通过激活线粒体凋亡途径以及下调Wnt/β-连环蛋白和AKT/mTOR途径，在人胃癌细胞的增殖、存活和运动中发挥致癌作用。当前研究为LYN在胃癌中的调控提供了全面的见解，并可能有助于开发新的肿瘤治疗策略。
