Chitooligosaccharides promote radiosensitivity in colon cancer line SW480.
OBJECTIVE
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).


CONCLUSIONS
COS can inhibit the proliferation of SW480 cells and enhance the radiosensitization of SW480 cells, inducing apoptosis and G2/M phase arrest.
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Fu-Shi
FS
Han
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Shi-Jie
SJ
Yang
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Mou-Bin
MB
Lin
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Ying-Qun
YQ
Chen
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Ping
P
Yang
Fu-Shi Han, Jin-Ming Xu, Department of Imaging, Tongji University Affiliated Yangpu Hospital, Shanghai 200090, China.
Jin-Ming
JM
Xu
D017209:Apoptosis / Q000528:radiation effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000528:radiation effects; D002686:Chitin / Q000031:analogs & derivatives* / Q000494:pharmacology; D048271:Chitosan; D003110:Colonic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D059565:G2 Phase Cell Cycle Checkpoints / Q000528:radiation effects*; D006801:Humans; D009844:Oligosaccharides; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
D009844:Oligosaccharides; D011838:Radiation-Sensitizing Agents; C493484:oligochitosan; D002686:Chitin; D048271:Chitosan
Apoptosis; Cancer of colon; Cell cycle; Chitooligosaccharides; Radiosensitization; Radiotherapy