[Effect of baicalein regulating miR-7 on autophagy in human gastric cancer BGC-823 cells and its mechanism of action].

Objective To investigate the effect of baicalein (BAI) on autophagy of gastric cancer cell line BGC-823 cells by upregulating microRNA-7-5p (miR-7) and its possible mechanism. Methods The MTT method was used to screen the optimal drug concentration of BGC-823 cells treated with BAI. Real-time quantitative PCR was used to detect the transfection efficiency of BGC-823 cell line stably transfected with miR-7. The experiment was divided into control group (mimic-NC), miR-7 group (miR-7 mimic) and BAI group ( miR-7 overexpression combined with BAI treatment group). MTT assay, plate cloning assay and EdU assay were used to detect cell proliferation. The expression levels of autophagy related 16 like 1 (ATG16L1), sequestosome 1 (p62), Beclin 1, autophagy-related protein 5 (ATG5) and microtubule-assaiated protein 1 light chain3 (LC3) were detected by immunofluorescence staining and Western blot. Network pharmacology analysis to predict possible signaling pathways; Western blot was used to detect the expression levels of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway. Results 50 μmol/L BAI significantly inhibited the proliferation ability of BGC-823 cells; Compared with the control group, the expression level of miR-7 was significantly increased after BAI treatment. The cell proliferation of the miR-7 group was significantly inhibited, and the protein expression level of autophagy-related proteins and the LC3II/LC3I ratio were significantly up-regulated, which promoted the formation of autophagosomes and inhibited the formation of autophagic flow in BGC-823 cells. Compared with the miR-7 group, the BAI group could further inhibit the proliferation of BGC-823 cells, induce the formation of autophagosomes, but inhibit the production of autophagy flow. Network pharmacology analysis showed that the common target genes of BAI, gastric cancer and autophagy may be related to PI3K/AKT signaling pathway. Compared with the control group, the phosphorylation levels of p-PI3K, p-AKT and p-mTOR in the miR-7 group were significantly inhibited, and the phosphorylation levels of these proteins were further inhibited in the BAI group. Conclusion BAI-mediated miR-7 inhibits the formation of autophagosomes in BGC-823 cells by inhibiting PI3K/AKT/mTOR signaling pathway, and inhibits the generation of autophagic flow.