THY-1 (CD90) expression promotes the growth of gastric cancer cells.

OBJECTIVE: To observe the expression of THY-1 (CD90) in gastric tumour cells and its effect on the growth of gastric cancer and to provide new evidence for the development of possible targets for the treatment of gastric cancer. METHODS: The effect of THY-1 on the proliferative ability of HGC-27, MGC-803 and AGS gastric cancer cells was examined by CCK-8 and cell cycle assays. The effect of THY-1 on the ability of gastric cancer cells to avoid apoptosis was analysed by Annexin V/PI double staining. The effect of THY-1 on the tumourigenic ability of gastric cancer cells in vivo was explored by subcutaneous tumour formation assay in nude mice. RESULTS: The CCK-8 assay showed that the proliferative activity of HGC-27 and MGC-803 gastric cancer cells was significantly limited after THY-1 interference in vitro (P < 0.01); however, exogenous THY-1 significantly promoted the growth of AGS gastric cancer cells (P = 0.003). The cell cycle assay showed that exogenous THY-1 reduced the G0/G1 phase arrest of AGS cells and facilitated cell entry into S phase, which accelerated cell division and proliferation (P = 0.008). After interference in the expression of the THY-1 gene, HGC-27 cells showed significant G0/G1 arrest, while the percentage of S phase cells decreased, and cell proliferation was inhibited (P < 0.001). The apoptosis assay showed that the average apoptosis rate of AGS cells was significantly lower in the overexpression group versus the control group (7.89 ± 1.08% vs. 11.90 ± 0.45%, P = 0.004). In contrast, the average apoptosis rate of HGC-27 cells was significantly increased in the interference group versus the control group (37.88 ± 5.47% vs. 22.84 ± 1.50%, P = 0.01). The subcutaneous tumour formation assay in nude mice revealed that at week 3, tumour volume and weight reached 1018.33 ± 521.48 mm3 and 81.47 ± 41.72 mg, respectively, in the control group, while tumour volume and weight were only 213.72 ± 111.94 mm3 and 17.10 ± 9.00 mg, respectively, in the interference group; the differences between the two groups were statistically significant (P < 0.01). CONCLUSIONS: THY-1 promoted the proliferation of gastric cancer cells and reduced the apoptosis rate of gastric cancer cells with a lack of nutrient supply. Moreover, THY-1 promoted subcutaneous tumour formation and growth in nude mice, as indicated by the results of the subcutaneous tumour formation assay.