The Role And Mechanism Of LncRNA ARHGAP27P1 In The Occurrence And Development Of Gastric Cancer

Background and Objective: Gastric cancer is the fifth most commonly diagnosed cancer and the third leading cause of cancer death in the world.In recent years,although the diagnosis and treatment of gastric cancer has made great progress,the 5-year survival rate is still not optimistic.Studies have found that long non-coding RNA(lncRNA)is associated with a variety of diseases,especially in relation to the development of tumors.ARHGAP27P1 is a pseudogene-derived lncRNA located on the 17q11 chromosome with a length of 3366 bp.Pre-experiment found that ARHGAP27P1 is down-regulated in gastric cancer tissues as well as cell lines.However,the expression and clinical significance of ARHGAP27P1 in gastric cancer tissues after further expansion of sample size are not clear.And the biological function and molecular mechanism of ARHGAP27P1 in gastric cancer need further study.Methods: 1.By searching for literature,electrophoresis and real-time fluorescent quantitative RT-PCR(RT-qPCR),lncRNA ARHGAP27P1 was screened;the expression level of ARHGAP27P1 in gastric cancer tissues and cell lines was detected by pre-experiment.2.RT-qPCR was used to detect the expression of ARHGAP27P1 in gastric cancer tissues and plasma,and analyze its relationship with parameters.The correlation between ARHGAP27P1 and survival time was analyzed by Log-rank.Draw a ROC curve to evaluate its diagnostic value.3.The effects of ARHGAP27P1 on cell proliferation,cell cycle,apoptosis,migration and invasion were studied in vitro using overexpression and knockdown experiments.4.The downstream genes regulated by ARHGAP27P1 were screened by RT-qPCR,and their molecular mechanisms were explored by Western blot,FISH,RIP and ChIP.5.The tumor formation experiment in nude mice further verified the effects of ARHGAP27P1 on GC formation.Results: 1.The results of RT-qPCR showed that ARHGAP27P1 was low in gastric cancer tissues and plasma.Pathological correlation analysis showed that the expression level of ARHGAP27P1 in gastric cancer tissues and plasma was significantly negatively correlated with TNM stage,invasion depth and lymph node metastasis.2.Cell function experiments show that overexpression of ARHGAP27P1 can inhibit cell cycle progression,promote cell apoptosis,inhibit gastric cancer cell proliferation,migration and invasion;and ARHGAP27P1 interference can promote cell cycle progression,proliferation,migration,invasion and inhibit cell apoptosis.3.RT-qPCR identified that p15,p16,p57 may be the downstream gene of ARHGAP27P1;Western blot confirmed that ARHGAP27P1 can affect p15,p16,p57 protein levels.4.FISH experiments showed that ARHGAP27P1 was mainly distributed in the nucleus,indicating that ARHGAP27P1 may play a role at the transcriptional level;RIP results showed that ARHGAP27P1 mainly binds to JMJD3;ChIP assay found that JMJD3 is involved in the regulation of transcriptional expression of p15,p16 and p57.5.Western blot showed that after overexpression of ARHGAP27P1,the level of H3K27me3 protein decreased,and the levels of p15,p16 and p57 protein increased.However,after ARHGAP27P1 overexpression and JMJD3 interference,the above effects could be completely reversed.In addition,interference with JMJD3,p15,and p16 reversed the anti-cancer effect of ARHGAP27P1.6.Tumor formation in nude mice showed that ARHGAP27P1 can significantly inhibit the formation of gastric cancer.Conclusions: ARHGAP27P1 was significantly downregulated in gastric cancer tissues and plasma,and its expression level was negatively correlated with TNM stage,tumor invasion depth and lymph node metastasis.Moreover,the overall survival rate of patients with high AHRGAP27P1 level was higher than that of patients with low AHRGAP27P1 level;ARHGAP27P1 can inhibit the proliferation,migration and invasion of gastric cancer cells and promote apoptosis.ARHGAP27P1 mediates the demethylation of H3K27me3 by binding to JMJD3,and promotes the expression of p15,p16 and p57,and then inhibiting the proliferation of gastric cancer cells.In vivo experiments show that ARHGAP27P1 can inhibit the formation of gastric cancer tumors.Therefore,ARHGAP27P1 is expected to be a new molecular marker for the diagnosis and treatment of gastric cancer.