RÉSUMÉ
Objective To investigate the proliferation and potential mechanism of CTHRC1 on gastric cancer cells. Methods The cancer tissues and adjacent tissues were collected of 8 gastric cancer patients diagnosed by pathology from Jun. 2017 to Jun. 2018 in Guangzhou Zengcheng People's Hospital. Human gastric mucosal GES-1 cells, and gastric cancer SGC-7901, BGC-823, BGC-803, MKN-45, and MKN-28 cells were purchased from Shanghai Cell Bank of Chinese Academy of Sciences. Western blotting was used to detect the expression of CTHRC1 protein in gastric cancer tissues, paracancerous tissues and gastric cancer cell lines SGC-7901, BGC-823, BGC-803, MKN-45, MKN-28 and human gastric mucosal GES-1 cells. After transfection of gastric cancer SGC-7901 cells with si-CTHRC1 and si-COL1A1, cell proliferation was detected by MTT assay, and the apoptosis rate was detected by flow cytometry. The target gene of CTHRC 1 was predicted by STRING database. Western blotting and immunofluorescence were performed to detect the expression of CTHRC1 and COL1A1 proteins in gastric cancer SGC-7901 cells transfected with si-CTHRC1. The expressions of CTHRC1 and COL1A1 proteins in gastric cancer tissues and the prognosis of gastric cancer patients were analyzed by Kaplan-Meier. Results The expression of CTHRC1 protein was significantly higher in gastric cancer tissues (0.87±0.13) than in adjacent tissues (0.31±0.20, P<0.05). The expression of CTHRC1 protein was higher in gastric cancer cell lines than in human gastric mucosa GES-1 cells with significant difference (P<0.05). The cell proliferation of gastric cancer SGC-7901 cells transfected by si-CTHRC1 decreased significantly. The cell vitality of gastric cancer SGC-7901 cells co-transfected by si-CTHRC1 and si-COL1A1 was lower (0.40±0.07) than those only transfected by si-CTHRC1 (0.87±0.05) or by si-COL1A1 groups (0.83±0.13, P<0.05). The apoptosis rate of gastric cancer SGC-7901 cells transfected by si-CTHRC1 (6.77%±1.55%) was higher than that in NC group (4.80%±1.93%) with statistical significance (P<0.05). The STRING database predicted that COL1A1 was a target gene for CTHRC1. For gastric cancer SGC-7901 cells transfected by si-CTHRC1, the relative expressions of CTHRC1 and COL1A1 proteins were 0.92±0.16 and 1.08±0.23, which were higher than those in NC group (0.55±0.15 and 0.65±0.12) with significant difference (P<0.05). Immunofluorescence showed that the expressions of CTHRC1 and COL1A1 proteins decreased significantly after transfection of si-CTHRC1 into gastric cancer SGC-7901 cells. Kaplan-Meier analysis showed that the 5-year survival rate of patients with high CTHRC1 expression in gastric cancer tissues was significantly lower (27.4%) than that of patients with low CTHRC1 expression (38.4%); The 5-year survival rate of patients with high COL1A1 expression in gastric cancer tissues (20.4%) was significantly lower than that in low expression patients (49.3%), the difference was statistically significant (P<0.001). Conclusion CTHRC1 promotes the proliferation of gastric cancer cells by overexpressing COL1A1 protein.