Study on functions and mechanism of curcumin in inducing colorectal carcinoma cells LoVo apoptosis / 中国中药杂志

<p><b>OBJECTIVE</b>To discuss the biological function and regulation mechanism of curcumin in promoting human colorectal carcinoma (LoVo) cells apoptosis.</p><p><b>METHOD</b>Conventional in vitro culture in human colorectal carcinoma cells LoVo, When 80%-90% confluence was reached, cells were treated with curcumin at different concentrations (0-20 mg x L(-1)). Curcumin's effect on cell proliferation level was examined by MTT colorimetry. The ultrastructure of curcumin-treated LoVo cells were observed with transmission electron microscope (TEM). The amount of PI-positive LoVo cells after the curcumin treatment were determined by flow cytometry. The cell apoptosis rate was detected by Annexin V-FITC/PI double staining. The mRNA level of Bax, Bcl-2, Caspase-3 and Bcl-xL were tested by means of RT-PCR.</p><p><b>RESULT</b>MTT test indicates curcumin could inhibite the growth and proliferation of LoVo cells in a time- and concentration-dependent manner. TEM examination showed that curcumin can make LoVo cell morphological changes, showing the typical characteristics of apoptotic cells. Flow cytometry instrument analysis showed that curcumin can arrest cell cycle at S phase, and induce apoptosis of LoVo cells. RT-PCR test showed that curcumin can activate the expression of Bax and Caspase-3, inhibit the expression of Bcl-2 and Bcl-xL at the mRNA level.</p><p><b>CONCLUSION</b>Curcumin can significantly inhibit the proliferation and induce the apoptosis of human colorectal carcinoma cells LoVo. Such biological effect may be associated with activating Caspase-3 signal channel by activating Bax expression and inhibiting Bcl-2 and Bcl-xL expression. This study lays an important foundation for further discussing the mechanism of curcumin in inducing human colorectal carcinoma LoVo apoptosis.</p>

Antitumor effects of curcumin and oxaliplatin combination on xenografts of human colon cancer LoVo cells in nude mice / 中草药

Objective: To investigate the effects of curcumin combined with oxaliplatin on the human colon cancer cells LoVo xenografted tumor in nude mice and to explore the mechanism. Methods: Nude mice were implanted with human colon cancer LoVo cells. All tumor-bearing mice were randomly divided into four groups and treated with vehicle, 50 mg/kg curcumin, 25 mg/kg oxaliplatin, and their combination (50 mg/kg curcumin + 25 mg/kg oxaliplatin) by ip injection once every other day individually. After continuous administration of drug treatment for 11 times, the weights of nude mice were recorded, the stripping tumor weight was monitored, and the tumor volume and tumor inhibitory rates were calculated. The enucleation of eyeball for taking blood and blood routine examination were carried out and the function of liver and kidney was detected. Tumor cell cycle and apoptosis rate were assayed by flow cytometry. The pathological morphology of tumor was analyzed by HE staining. The apoptosis related gene expression was detected by RT-PCR. Results: Tumor inhibitory rates of curcumin, oxaliplatin, and curcumin + oxaliplatin groups were 59.47%, 55.49%, and 70.56%, respectively. Curcumin combination with oxaliplatin did not influence the blood system, liver, and kidneys in nude mice. Combination of curcumin and oxaliplatin could effectively inhibit the tumor growth (P < 0.05), interfere with cell cycle arresting at S and G2/M phases (P < 0.05, 0.01), and promote the expression of bax (P < 0.01) in tumor-bearing nude mice. Conclusion: Combination of curcumin and oxaliplatin could synergistically inhibit the growth of LoVo colonic xenografts in nude mice.