Zhongguo aizheng zazhi (Apr 2023)
LncRNA DLEU7-AS1 contributes to proliferation and migration of gastric cancer by regulating MSN transcription
Abstract
Background and purpose: An increasing number of studies have demonstrated that lncRNA plays a critical role in the occurrence and development of tumors. However, the function of lncRNA in human gastric cancer remains largely unknown. So far, the role and mechanism of lncRNA DLEU7-AS1 in gastric cancer have not been reported. This study aimed to investigate the effect of DLEU7-AS1on the tumorigenesis and progression of gastric cancer and its mechanism. Methods: The public database the Cancer Genome Atlas (TCGA) was used to analyze the expression of DLEU7-AS1 in gastric cancer tissues and the correlation between its expression and the survival of gastric cancer patients. Then real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) was performed to verify the expression of DLEU7-AS1 in gastric cancer tissues and gastric cancer cell lines. Gastric cancer cell lines were treated with 5-aza-2’-deoxycytidine (DAC) and trichostatin A (TSA) to explore whether epigenetic regulation participated in DLEU7-AS1 transcription. SiRNA was used to down-regulate the expression of DLEU7-AS1 in HGC-27 and AGS cells, and recombinant plasmid was used to up-regulate the expression of DLEU7-AS1 in MGC-803 and MKN-45. The effect was verified by RTFQ-PCR. Cell biological experiments, such as cell counting kit-8 (CCK-8) cell proliferation toxicity test, transwell chamber assay, plate colony formation assay and flow cytometry were used to investigate the effect of DLEU7-AS1 on the proliferation, migration, apoptosis and cell cycle progression of gastric cancer cells. RNA sequencing (RNA-seq) was used to analyze downstream signal pathways after silencing DLEU7-AS1 and tested by RTFQ-PCR and Western blot. And RNA Co-immunoprecipitation (RIP) was used to explore the regulatory mechanism of DLEU7-AS1 on downstream signal molecules. Results: The results of public database analysis and RTFQ-PCR demonstrated that DLEU7-AS1 was up-regulated in gastric cancer tissues compared with normal tissues. DLEU7-AS1 expression was negatively correlated with the survival of gastric cancer patients. DLEU7-AS1 was up-regulated in gastric cancer cell lines treated with DAC and TSA, indicating that its expression was epigenetically regulated. DLEU7-AS1 downregulation inhibited gastric cancer cells proliferation and migration and promoted cell apoptosis, while overexpression of DLEU7-AS1 promoted cell proliferation and metastasis and inhibited cell apoptosis. The results of RNA-seq showed that the downregulation of DLEU7-AS1 expression led to a significant decrease in moesin (MSN) expression, which was confirmed by RTFQ-PCR and Western blot. Rescue experiment results further verified that MSN overexpression could partially restore the inhibition effect of knockdown of DLEU7-AS1 on the proliferation and migration of gastric cancer cells. Considering that DLEU7-AS1 mainly located in the nucleus, DLEU7-AS1 binding to P300 and H3K27 highly enriched near the MSN promoter, it was proposed that DLEU7-AS1 might regulate the expression of MSN by recruiting P300, thus contributing to the proliferation and migration of gastric cancer cells. Conclusion: LncRNA DLEU7-AS1 is abnormally up-regulated in gastric cancer and negatively correlated with survival of gastric cancer patients. DLEU7-AS1 may promote the proliferation and migration of gastric cancer by recruiting P300 to regulate the transcription of MSN, which provides a new idea for the diagnosis and treatment of gastric cancer..
Keywords
