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

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.

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.

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).

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.