Effects of LncRNA SBF2-AS1 targeting miR-375 on immune escape and mTOR1 signaling pathway of gas-tric cancer cells
Objective To explore the effects of LncRNA SBF2-AS1 targeting miR-375 on immune escape and mTOR1 signaling pathway of gastric cancer cells.Method The expression levels of LncRNA SBF2-AS1 and miR-375 in normal gastric epithelial cells and 4 gastric cancer cell lines were detected by real-time PCR.Gastric can-cer cells were collected and divided into gastric cancer cells(GC)group,gastric cancer cells+LncRNA SBF2-AS1-NC(SN)group,gastric cancer cells+LncRNA SBF2-AS1 agonist(SM)group,and gastric cancer cells+LncRNA SBF2-AS1 inhibitor(SI)group,gastric cancer cells+Mir-375-NC(MN)group,gastric cancer cells+miR-375 in-hibitor(MI)group,gastric cancer cells+miR-375 agonist(MM)group,gastric cancer cells+LncRNA SBF2-AS1 inhibitor+miR-375 agonist(IM)group.Immunoescape related factors and mTOR1 signaling pathway protein expres-sion were detected by Western blot,and the interaction between LncRNA SBF2-AS1 and miR-375 was confirmed by dual luciferase reporting assay.Results LncRNA SBF2-AS1 mRNA expression in gastric cancer cell line was signif-icantly higher than that in normal gastric epithelial cell line NGEC(P<0.05).The mRNA expression of miR-375 was significantly lower than that of normal gastric epithelial cell line NGEC(P<0.05),and the LncRNA SBF2-AS1 and miR-375 mRNA values of HGC-27 cells had the largest changes(P<0.05),so they were selected as the experimen-tal cells.There were basically no differences in the protein expressions of PD-1,PD-L1,mTOR1,p70S6K and 4EBP1 in GC group,SN group and MN group(P>0.05).The protein expressions of PD-1,PD-L1,mTOR1,p70S6K and 4EBP1 in SM group and MI group were significantly increased(P<0.05);compared with SM group and MI group,the protein expressions of PD-1,PD-L1,mTOR1,p70S6K and 4EBP1 in SI group and MM group were significantly decreased(P<0.05).Compared with SI group and MM group,the protein expressions of PD-1,PD-L1,mTOR1,p70S6K and 4EBP1 in IM group were significantly decreased(P<0.05).The results of dual luciferase re-port showed that transfection of LncRNA SBF2-AS1 could significantly reduce the luciferase activity of miR-375-3'-UTR-WT(P<0.05),but had no significant effect on mutated genes(P>0.05).Conclusion Inhibition of LncRNA SBF2-AS1 can effectively inhibit immune escape of gastric cancer cells and inhibit the expression of mTOR1 signal-ing pathway,and the mechanism of action may be related to the targeted activation of miR-375.