ABSTRACT
AIM: To investigate the anti-proliferation and radiosensitization effect of chitooligosaccharides (COS) on human colon cancer cell line SW480. METHODS: SW480 cells were treated with 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mg/mL of COS for 48 h. CCK-8 assay was employed to obtain the cell survival ratio of SW480 cells, and the anti-proliferation curve was observed with the inhibition ratio of COS on SW480 cells. The RAY + COS group was treated with 1.0 mg/mL of COS for 48 h, while both the RAY and RAY+COS groups were exposed to X-ray at 0, 1, 2, 4, 6 and 8 Gy, respectively. Clonogenic assay was used to analyze cell viability in the two groups at 10 d after treatment, and a cell survival curve was used to analyze the sensitization ratio of COS. The RAY group was exposed to X-ray at 6 Gy, while the RAY+COS group was treated with 1.0 mg/mL of COS for 48 h in advance and exposed to X-ray at 6 Gy. Flow cytometry was employed to detect cell cycle and apoptosis rate in the non-treatment group, as well as in the RAY and RAY + COS groups after 24 h of treatment. RESULTS: COS inhibited the proliferation of SW480 cells, and the inhibition rate positively correlated with the concentration of COS (P < 0.01). Cell viability decreased as radiation dose increased in the RAY and RAY+COS groups (P < 0.01). Cell viabilities in the RAY+COS group were lower than in the RAY group at all doses of X-ray exposure (P < 0.01), and the sensitization ratio of COS on SW480 cells was 1.39. Compared with the non-treatment group, there was a significant increase in apoptosis rate in both the RAY and RAY + COS groups; while the apoptosis rate in the RAY+COS group was significantly higher than in the RAY group (P < 0.01). In comparing these three groups, the percentage of G2/M phase in both the RAY and RAY + COS groups significantly increased, and the percentage of the S phase and G0/G1 phase was downregulated. Furthermore, the percentage in the G2/M phase was higher, and the percentage in the S phase and G0/G1 phase was lower in the RAY + COS group vs RAY group (P < 0.01). CONCLUSION: COS can inhibit the proliferation of SW480 cells and enhance the radiosensitization of SW480 cells, inducing apoptosis and G2/M phase arrest.
Subject(s)
Apoptosis/radiation effects , Cell Proliferation/drug effects , Chitin/analogs & derivatives , Colonic Neoplasms/radiotherapy , G2 Phase Cell Cycle Checkpoints/radiation effects , Radiation Tolerance/drug effects , Radiation-Sensitizing Agents/pharmacology , Cell Line, Tumor , Cell Survival/radiation effects , Chitin/pharmacology , Chitosan , Colonic Neoplasms/pathology , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Humans , OligosaccharidesABSTRACT
OBJECTIVE: To investigate the anti-proliferation effect and mechanism of zoledronic acid (ZOL) on human colon cancer line SW480. METHODS: SW480 cells were treated with 0, 12.5, 25, 50, 100 and 200 µmoL/L of ZOL for 48 h, and CCK-8 assay was employed to obtain the survival rate of SW480 cells. SW480 cells were treated with 25 µmoL/L of ZOL for 0, 12, 24, 48 and 72 h, and then the survival rate was obtained. SW480 cells of the ZOL group were treated with 25 µmoL/L of ZOL for 48 h, while cells of the CsA + ZOL group were pretreated with 10 µmoL/L of CsA for 0.5 h and then treated with 25 µmoL/L of ZOL for 48 h. Then the survival rates of SW480 cells of the control group, ZOL group and CsA + ZOL group were determined. Flow cytometry was employed to detect the apoptosis rate and the mitochondrial transmembrane potential (â³Ψm) of the three groups and Western blot was used to detect the expressions of cyt C in the cytosol of the three groups. RESULTS: ZOL inhibited the proliferation of SW480 cells, and the inhibition rate positively correlated with the concentration of ZOL and the action time (P < 0.01). The cell survival rate and the â³Ψm of the ZOL group were greatly lower than those of the control group, while the apoptosis rate and the expression of cyt C in the cytosol were obviously higher than those of the control group. All the differences showed distinctly statistical significances (P < 0.01). The cell survival rate and the â³Ψm of the CsA + ZOL group were all lower than those of the control group, but substantially higher than those of the ZOL group; while the apoptosis rate and the expression of cyt C in the cytosol were higher than those of the control group, but distinctly lower than those of the ZOL group. All the differences were statistically significant (P < 0.01). CONCLUSIONS: ZOL can induce the apoptosis in human colon cancer line SW480 and then inhibit the proliferation of SW480 cells directly by opening the mitochondrial permeability transition pore abnormally, decreasing â³Ψm, and releasing the cyt C into the cytosol. And the effect enhances with the increases of the concentration of ZOL and the action time.
