| Background and purpose: Colon cancer is a common digestive system malignant tumor that is a threat to human health and life, with high morbidity and mortality. At present, each year more than 1 million new cases of colon cancer patients in world,the mortality rate ranks the third in a variety of malignancies.The high occurrence and development of colon cancer is the result from the interaction of multiple factors,with high-speed and high-confidentiality, and short period of survival of patients.Colon cancer has become a kind of malignant tumor that is a very serious threat to life. Currently, the treatment of colon cancer was still a simplification, including resection, chemotherapy and radiotherapy, but the effect is out of ideal, with high postoperative recurrence of patients. Now 5 FU, mitomycin and huanya urea nitrate are often used as a series of main chemotherapeutics, but clinical effect is far away from satisfactory. Therefore, looking for a new kind of high-efficiency, low-toxicity natural plant medicines for the treatment of colon cancer has the vital clinical significance.Lutein is a kind of carotenoids oxygen, which mainly being found in fruits and vegetables, that is a natural antioxidant plant chemicals. It is lutein that has the prevention and treatment of retinopathy, pigment denaturation, protect eyesight and the function of slowing hardening of the arteries. Meanwhile,lutein is playing a very important role in antioxidant, anti-inflammatory and anticancer. Our previous studies has demonstrated: a certain concentration of lutein can obviously inhibit proliferation of the liver cancer, gastric cancer, breast cancer and even esophageal cancer cells. This experiment is intended to explore the lutein on colon cancer HT29 cells proliferation inhibition and its possible molecular mechanisms.Methods: The growth curve of human colon cancer HT29 cells was established for 8days with cck8 method; Cultivate HT29 cells in 96 wells added different concentration of lutein for 24 h,48h,72 h,and then the inhibitory effect of lutein on the proliferation of HT29 cells was tested by cck8 assay; The morphology change of HT29 cells with lutein was observed with inverted microscope; Colon cancer HT29 cells cycle distribution was measured by flow cytometry; Deal with HT29 cell with different concentrations of lutein after 48 h, the changes of the m RNA expression level and the protein expression level of intracellular Nrf-2 and HO-1 was analyzed by RT-PCR and Western blot assay,respectively.Results: the cck8 test results show that lutein can significantly inhibit human colon cancer HT29 cells proliferation, and with time and dose dependent(P < 0.01).Treated with lutein of 80mg·L-1 for 24 h,38h,72 h respectively, the inhibition rates were 24.92%,45.11% and 53.68%.When the concentration of lutein increased to 160mg·L-1, the inhibitory rates were increased to30.91%, 58.51%, 78.09%,separately. According to the Flow cytometry results: HT29 cells cycle was markedly arrested with lutein for 48 h,and the percentage of cells in G0 / G1 phase increased significantly, it is indicates that lutein can block the growth of HT29 cells in G0 / G1 phase. As the results of RT-PCR were shown: the m RNA expression level of intracellular Nrf-2 and HO-1 of being treated with different concentration of lutein to be compared to control group is more obviously raised, and with a dose dependent, that is, lutein can affect the Nrf-2 and HO-1 gene transcription. Western blot demonstrates that compared to control group, the Nrf-2 and HO-1 protein expression level of experimental grop is raised obviously, and has a dose dependent(P < 0.01).Conclusion: The lutein can significantly inhibit the proliferation of HT29 colon cancer cells. The mechanism may be related to arrest cells proliferation in G0 / G1 phase, increase Nrf-2 and HO-1 m RNA expression,upregulate the Nrf-2/ARE pathway Nrf-2 and HO-1 protein expression level. |
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