Abstract: Background and purpose: Protein arginine methyltransferase 5 (PRMT5) is an enzyme that can regulate cell cycle. It can affect cell proliferation and apoptosis by regulating cell division cycle. This study aimed to explore the expression of PRMT5 in gastric cancer and its influences on proliferation, apoptosis and migration ability of gastric cancer cells. Methods: Western blot was performed to detect PRMT5 expression in gastric cancer tissues and adjacent normal tissues from 88 patients with gastric cancer who received surgery in Hainan Tumor Hospital from May 2016 to Jan. 2019. The relationship between relative expression level of PRMT5 and clinical features of gastric cancer was analyzed. PRMT5 small interfering RNA (PRMT5-siRNA) and negative control (siRNA-NC) were transfected into human gastric cancer cell line SGC-7901. The untransfected SGC-7901 cells were enrolled as control group. Real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) and Western blot assay were performed to detect the expression levels of PRMT5 mRNA and protein in cells after transfection. Cell proliferation was detected by cell counting kit-8 (CCK-8) method. Apoptosis was detected by flow cytometry. Cell migration ability was detected by scratch assay. Transwell cell invasion assay was performed to detect cell invasion ability. Western blot method was performed to detect expressions of cleaved caspase-3, phosphoinosmde-3-kinase (PI3K), protein kinase B (AKT) and phosphorylated-AKT (p-AKT) protein. Results: The expression of PRMT5 in gastric cancer tissues was higher than that in adjacent tissues (P<0.01). The expression level of PRMT5 was correlated with pathological grading, staging and lymph node metastasis of gastric cancer (P<0.05). After transfection, there was no significant difference in expression levels of PRMT5 mRNA and protein, proliferation rate of gastric cancer cells, apoptotic rate, protein expression levels of cleaved caspase-3, PI3K, p-AKT and AKT, scratch healing rate and number of cell invasion between siRNA-NC group and control group (P>0.05). After transfection, expression levels of PRMT5 mRNA and protein, proliferation rate of gastric cancer cells, protein expression levels of PI3K, p-AKT and AKT, scratch healing rate and number of cell invasion in siRNA-NC group and control group were higher than those in PRMT5-siRNA group, while apoptotic rate and cleaved caspase-3 expression in siRNA-NC group and control group were lower than those in PRMT5-siRNA group (P<0.05). Conclusion: The expression of PRMT5 is significantly increased in gastric cancer tissues. The expression level of PRMT5 is closely related to occurrence and development of gastric cancer and metastasis. Down-regulation of PRMT5 expression can significantly attenuate proliferation and migration ability and promote apoptosis of gastric cancer cells.

Key words: Gastric cancer, Protein arginine methyltransferase 5, Cell proliferation, Apoptosis, Migration ability