[Effects of metformin on proliferation of human colon carcinoma cell line SW-480].
OBJECTIVE
To observe the effect of metformin on the proliferation of SW-480 cells and study the possible mechanism.


METHODS
The proliferation of SW-480 cells treated with different concentrations of metformin was assessed by MTT assay, and the cell cycle changes were analyzed by flow cytometry. The expression of cyclin D1 in the treated cells was detected by Western blotting, and telomerase activity examined by telomeric repeat amplification protocol (TRAP) silver staining.


RESULTS
Metformin decreased the proliferation of SW-480 cells in a dose- and time-dependent manner. The proportion of the cells at G0/G1 stage in the control and metformin-treated (5 mmol/L, 72 h) cells was (55.81-/+0.63)% and (63.38-/+0.99)%, the cell proportion at S stage was (31.11-/+3.05)% and (25.29-/+1.64)%, and that at G2/M stage was (13.09-/+3.00)% and (11.33-/+2.60)%, respectively. The expression of cyclin D1 in metformin-treated cells were lowered significantly as compared with that in the control cells. Telomerase activity was also decreased significantly in the cells after treatment with 5 mmol/L metformin for 72 h.


CONCLUSIONS
Metformin can inhibit the growth of SW-480 cells mainly by blocking the cell cycle at G0/G1, down-regulating the expression of cyclin D1 and decreasing telomerase activity.
Zhou
Xiao-zhi
XZ
Department of Endocrinology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. zxz20020013@163.com
Xue
Yao-ming
YM
Zhu
Bo
B
Sha
Jian-ping
JP
D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D019938:Cyclin D1 / Q000378:metabolism; D006801:Humans; D008687:Metformin / Q000494:pharmacology*; D019098:Telomerase / Q000378:metabolism
C530104:CCND1 protein, human; D019938:Cyclin D1; D008687:Metformin; D019098:Telomerase