Comparative study of the chitooligosaccharides effect on the proliferation inhibition and radiosensitization of three types of human gastric cancer cell line

Objective: To observe the chitooligosaccharides (COS) effect on the proliferation inhibition and radiosensitivity of three types of human gastric cancer cell line. Mothods: CCK-8 assay was employed to obtain the inhibition ratio of COS on BGC823 cells, MKN45 cells and SGC7901 cells at 48 h after treatment and the proliferation-inhibition curve was drawn with the inhibition ratio of COS on three types of cells. The clonogenic assay was used to detect the cell viability of 0, 1, 2, 4, 6 and 8 Gy (6 dose grades) in RAY group and RAY + COS group after X-ray, and the cell survival curve was used to analyze the sensitization enhancement ratio of COS. Flow cytometry was employed to detect cell cycle and apoptosis rate in control group, RAY group and RAY + COS group after 48 h treatment. Results: COS inhibited the proliferation of three types of cells. The inhibition rate was positively correlated with the concentration of COS, and the susceptibility of MKN45 cells, SGC7901 cells and BGC823 cells to COS decreased in turn. The cell viability decreased gradually with the increasing radiation dose in RAY group and RAY + COS group (P < 0.01). The cell viabilities of RAY + COS group were lower than those of RAY group at all the dose grades under X-ray exposure (P < 0.01), and the sensitization enhancement ratios of COS on BGC823 cells, MKN45 cells and SGC7901 cells were 1.06, 1.28 and 1.15, respectively. In controlled trials, apoptosis rate and percentage in the G2/M phase of three types of cells in RAY + COS group were higher than those in control group and RAY group, and percentage in the S phase and the G(0)/G(1) phase in RAY + COS group were lower than those in the other two groups (P < 0.01). Conclusions: COS can inhibit the proliferation of three types of human gastric cancer cells and enhance the radiosensitivity by inducing apoptosis and G2/M phase arrest.