Effects of silencing Sema4D on the growth, autophagy and epithelial-mesenchymal transformation of gastric cancer cells SGC-7901

Objective　To investigate the effects of silencing axon guide protein 4D (Sema4D) on the growth, autophagy and epithelial-mesenchymal transformation of gastric cancer cell SGC-7901. Methods　The cells were randomly divided into control group, shRNA-NC group, Sema4D-shRNA1 group, Sema4D-shRNA2 group and Sema4D-shRNA3 group, and transfected into SGC-7901 with shRNA Sema4D vector. The expression of Sema4D mRNA was detected by RT-PCR. The clone formation rate was determined by colony formation assay. Flow cytometry was used to detect apoptosis. Morphological changes of epithelialmesenchymal transformation were observed microscopically. Western blotting was used to detect the expression levels of Ki67, proliferating cell nuclear antigen (PCNA), Bax, Bcl-2, caspase-3, cleaved caspase-3, Beclin1, p62, LC3Ⅰ, LC3Ⅱ, E-cadherin, N-cadherin, and vimentin proteins. Results　The results of RT-PCR showed that compared with the control group, the mRNA levels of Sema4D-shRNA1 group, Sema4D-shRNA2 group and Sema4D-shRNA3 group were significantly lower, and the mRNA level of Sema4D-shRNA3 group was significantly lower than that of Sema4D-shRNA1 group and Sema4D-shRNA2 group (P<0.05). Sema4D-shRNA3 was selected for subsequent experiments. The results of colony forming assay showed that the colony forming efficiency of Sema4D-shRNA3 group was significantly lower than that of the control group (P<0.05). Flow cytometry results showed that compared with the control group, the apoptosis rate of Sema4D-shRNA3 group was significantly increased (P<0.05). Western blotting results showed that compared with the control group, the expression levels of Ki67, PCNA, p62, N-cadherin and vimentin proteins in the Sema4D-shRNA3 group were significantly lower, Beclin1 and E-cadherin proteins were significantly higher, and the ratios of Bax/Bcl-2, cleaved caspase-3/caspase-3 and LC3Ⅱ/LC3Ⅰ were significantly higher (P<0.05). Microscopically, the epithelial-mesenchymal transformation was inhibited in the Sema4D-shRNA3 group. Conclusion　shRNA Sema4D can inhibit proliferation, autophagy and epithelial-mesenchymal transformation of SGC-7901 cells and promote apoptosis. DOI: 10.11855/j.issn.0577-7402.2021.01.03