Objective： To investigate the effects ofursolic acid on the proliferation and apoptosis of human HT-29 colon cancer cells. Methods： 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and flow cyt...Objective： To investigate the effects ofursolic acid on the proliferation and apoptosis of human HT-29 colon cancer cells. Methods： 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and flow cytometry assays were performed to evaluate the effects of ursolic acid on the growth and apoptosis of HT-29 cells. Western blot analysis was applied to investigate the inhibitory efibcts of ursolic acid on the phosphorylation of the epidermal growth factor receptor （EGFR）, extracellular signal-regulated kinase （ERK）, c-Jun N-terminal kinase （JNK）, and p38 mitogen-activated protein kinase （p38 MAPK）, and the activity of B cell leukemia-2 （Bcl-2）, B cell leukemia-xL （Bcl-xL）, caspase-3, and caspase-9. Results： Ursolic acid inhibited the growth of HT-29 cells in dose- and time-dependent manners. The median inhibition concentration （IC50） values for 24, 48, and 72 h treatment were 26, 20, and 18 pmol/L, respectively. The apoptotic rates of 10, 20, and 40 μmol/L ursolic acid treatments for 24 h were 5.74%, 14.49%, and 33.05%, and for 48 h were 9%, 21.39%, and 40.49%, respectively. Ursolic acid suppressed the phosphorylation of EGFR, ERK1/2, p38 MAPK, and JNK, which is well correlated with its growth inhibitory effect. 10, 20, and 40 μmol/L ursolic acid significantly inhibited the proliferation of EGF-stimulated HT-29 cells （P〈0.05）. Cell proliferation was most significantly inhibited when treated with 10 and 20 μmol/L ursolic acid combined with 200 nmol/L AG 1478 or 10 μmol/L U0126 （P〈0.01）. Besides, it also down-regulated the expression of Bcl-2 and Bcl-xL and activated caspase-3 and caspase-9. Conclusion： Ursolic acid induces apoptosis in HT-29 cells by suppressing the EGFR/MAPK pathway, suggesting that it may be a potent agent for the treatment of colorectal cancer.展开更多
基金supported by the Hi-Tech Research and Development Program (863) of China (No. 2006AA02Z341)the Science and Technology Research Program of Zhejiang Province, China (No. 2008C30037)
文摘Objective： To investigate the effects ofursolic acid on the proliferation and apoptosis of human HT-29 colon cancer cells. Methods： 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and flow cytometry assays were performed to evaluate the effects of ursolic acid on the growth and apoptosis of HT-29 cells. Western blot analysis was applied to investigate the inhibitory efibcts of ursolic acid on the phosphorylation of the epidermal growth factor receptor （EGFR）, extracellular signal-regulated kinase （ERK）, c-Jun N-terminal kinase （JNK）, and p38 mitogen-activated protein kinase （p38 MAPK）, and the activity of B cell leukemia-2 （Bcl-2）, B cell leukemia-xL （Bcl-xL）, caspase-3, and caspase-9. Results： Ursolic acid inhibited the growth of HT-29 cells in dose- and time-dependent manners. The median inhibition concentration （IC50） values for 24, 48, and 72 h treatment were 26, 20, and 18 pmol/L, respectively. The apoptotic rates of 10, 20, and 40 μmol/L ursolic acid treatments for 24 h were 5.74%, 14.49%, and 33.05%, and for 48 h were 9%, 21.39%, and 40.49%, respectively. Ursolic acid suppressed the phosphorylation of EGFR, ERK1/2, p38 MAPK, and JNK, which is well correlated with its growth inhibitory effect. 10, 20, and 40 μmol/L ursolic acid significantly inhibited the proliferation of EGF-stimulated HT-29 cells （P〈0.05）. Cell proliferation was most significantly inhibited when treated with 10 and 20 μmol/L ursolic acid combined with 200 nmol/L AG 1478 or 10 μmol/L U0126 （P〈0.01）. Besides, it also down-regulated the expression of Bcl-2 and Bcl-xL and activated caspase-3 and caspase-9. Conclusion： Ursolic acid induces apoptosis in HT-29 cells by suppressing the EGFR/MAPK pathway, suggesting that it may be a potent agent for the treatment of colorectal cancer.
