Down-regulation of ubiquitin specific peptidase 18 suppresses the invasion and proliferation of gastric cancer cells

Abstract

Objective To analyze the expression and role of ubiquitin specific peptidase 18 (USP18)in gastric cancer cells, and to investigate the relationship between the development of gastric cancer and USP18. Methods The levels of USP18 protein and mRNA expression in immortalized gastric mucosa epithelial GSE cell lines and gastric cancer cell lines (AGS, MKN45, MKN25, BGC823, BGC803, SGC7901) were detected by using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. The role of USP18 in the invasion and proliferation of gastric cancer cells was analyzed by using CCK8 and Transwell assays. Results The mRNA level of USP18 was lower in GSE cell lines than that in gastric cancer cells (F= 794.052, P < 0.000 1). In six gastric cancer cell lines, mRNA level of USP18 was relatively high in BGC823 (17.62±0.55) and BGC803 (13.52±0.50) cell lines, and low in MKN28 (1.40±0.17) and MKN45 cell lines (4.23±0.26). As for the protein level, the expression of USP18 was lowest in GSE cell line. In six gastric cancer cell lines, the expression of USP18 was the highest in more aggressive SGC7901 and BGC803 cell lines and the lowest in AGS and MKN45 cells. Compared with the control group, interference of USP18 decreased the invasion and proliferation abilities of SGC7901 and BGC803 cell lines (P < 0.01). Conclusion USP18 is highly expressed in more invasive gastric cancer cells, and the down-regulation of USP18 can suppress the invasion and proliferation of gastric cancer cells. Key words: Stomach neoplasms; Ubiquitin specific peptidase 18; Neoplasm invasiveness; Cell proliferation