| Objective Gastric cancer is one of the most common gastrointestinal tumors with high morbidity and high mortality.At present,the treatment of gastric cancer has not achieved satisfactory results,and further research is needed to find more effective targeted drugs.Our research group has studied a novel anticancer bioactive peptide(ACBP)extracted from goat liver for a long time.Previous research results showed that ACBP significantly inhibited tumor cell proliferation,induced apoptosis,regulated the cell cycle,and regulated immune cells.This study focused on the mechanism of ACBP inhibited the proliferation and migration of gastric cancer cells by regulating the expression of LncRNA MIR22 HG.Method LncRNA expression data of gastric cancer cell line MKN-45 after ACBP treatment were analyzed by transcriptomics sequencing,ACBP related lncRNAs that were abnormally expressed in gastric cancer cells;LncRNA MIR22 HG was selected as the focus of this research.qRT-PCR was used to detect the expression of lncRNA MIR22 HG in ACBP treated gastric cancer MKN-45 and AGS cells;Subsequently,it was verified in 66 pairs of gastric cancer tissue and gastric cancer cells.The subcellular localization of lncRNA MIR22 HG in gastric cancer MKN-45 and AGS cells and ACBP-treated MKN-45 and AGS cells were determined by nuclear separation and qRT-PCR;Methylation-specific PCR(MSP)was used to detect the methylation status of the lncRNA MIR22 HG promoter region in gastric cancer cells and the methylation status of the lncRNA MIR22 HG promoter region after ACBP treatment of gastric cancer cells;The CHIP(chromatin immunoprecipitation)experiment was used toanalyze the enrichment of EZH2 and H3K27me3 proteins in the lncRNA MIR22 HG promoter region;Gastric cancer MKN-45 and AGS cells were added with ACBP and transfected Pc DNA3.1-MIR22 HG in vitro;We deeply studied the effects of ACBP and lncRNA MIR22 HG and their synergy on the biological function of gastric cancer cell proliferation(CCK8,plate colony formation and EDU experiment)and migration(transwell assay).Studies have established Zebrafish gastric cancer model in vivo,to investigate the effects ACBP(0.1?g / ml)on the inhibition of gastric tumor formation and migration.Results The expression profile of lncRNA in ACBP-treated MKN-45 cell was analyzed and detected by qRT-PCR assay,we determined that ACBP induced the expression of lncRNA MIR22HG(P <0.05).And it was found,compared to normal gastric tissue and gastric epithelial cells,the expression of lncRNA MIR22 HG decreased significantly in 66 pairs of gastric cancer tissues and gastric cancer cells(P <0.01).It was also found that lncRNA MIR22 HG was mainly located in the nucleus of gastric cancer MKN-45 and AGS cells and ACBP-treated gastric cancer MKN-45 and AGS cells(P <0.05).MSP and CHIP experiments found that ACBP induced lncRNA MIR22 HG promoter demethylation and suppresed H3k27me3 modification of lncRNA MIR22 HG promoter core region by EZH2 to promote lncRNA MIR22 HG transcription(P <0.05).Studies confirmed that ACBP and lncRNA MIR22 HG can significantly inhibit the proliferation and migration of gastric cancer MKN-45 or AGS cells in vitro(P <0.05).Zebrafish gastric cancer model was established,and some studies confirmed that 0.1?g/ml ACBP significantly inhibited the formation and metastasis of gastric cancer in vivo,while up-regulating lncRNA MIR22 HG significantly enhanced ACBP's inhibition of gastric tumor progression(P <0.05).Conclusions(1)ACBP inducing lncRNA MIR22 HG and inhibiting the expression of EZH2 in gastric cancer cells was one of its antitumor mechanisms;(2)LncRNA MIR22 HG had antitumor effects in gastric cancer cell lines;(3)ACBP induced lncRNA MIR22 HG promoter demethylation and suppresed H3k27me3 modification of lncRNA MIR22 HG promoter coreregion by EZH2 to promote lncRNA MIR22 HG transcription;(4)Up-regulation of lncRNA MIR22 HG can enhance ACBP's inhibition of gastric cancer progression in vivo and in vitro. |
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