MiR-340-5p affects the proliferation and transfer of gastric cancer cells by targeting lncRNA HCG11 and NRF2 expression

Abstract Objective The aim of the study was to investigate the expression and biological role of nuclear factor erythroid–related factor 2 (NRF2) in gastric cancer cells. Methods Western blotting (WB) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the expression of NRF2 in the tumor tissues of patients with gastric cancer and MKN45 cells. NRF2 was transfected into MKN45 gastric cancer cells, and apoptosis was detected using flow cytometry. The 3-(4,5-dimethylthiazole-2-yl)-2.5-dipheny-tetrazolium bromide (MTT) assay was performed to detect cell proliferation. Transwell and scratch experiments were performed to detect cell invasion and migration rates. WB blotting was performed to detect Bcl-2, COX-2, PEG2, Bax, and Cyt-C protein expression. RT-PCR was used to detect Bcl-2, COX-2, PEG2, Bax, Cyt-C, miR-340-5p, lncRNA HCG11, and NRF2 mRNA expression. Results NRF2 expression increased in gastric cancer tissues and in the MKN45 gastric cancer cell model. Compared with the blank group, the shNRF2 knockdown group showed a significant increase in the MKN45 gastric cancer cell apoptosis rate ( p < 0.05) and a significant decrease in invasion and migration rates ( p < 0.05). WB and RT-PCR showed that, in the shNRF2 knockdown group, Bcl-2 protein and mRNA, miR-340-5p, and lncRNA HCG11 expression was significantly increased, whereas COX-2, PEG2, Bax, and Cyt-C protein and mRNA expression was significantly reduced ( p < 0.05). In the NRF2 overexpression group, Bcl-2 protein and mRNA expression was significantly reduced, whereas COX-2, PEG2, Bax, and Cyt-C protein and mRNA expression was significantly increased ( p < 0.05). The opposite was observed for the NRF2 overexpression group. When miR-340-5p mimics were transfected into MKN45 gastric cancer cells, NRF2 and HCG11 expression significantly reduced ( p < 0.05). When the miR-340-5p inhibitor was transfected into MKN45 gastric cancer cells, NRF2 and HCG11 expression significantly increased ( p < 0.05). Conclusions The invasion, migration, abnormal proliferation, and apoptosis of MKN45 gastric cancer cells are closely related to an imbalance in NRF2 expression, suggesting that MiR-340-5p may target and regulate the lncRNA HCG11, thereby inhibiting NRF2 expression.