The Research On The Apoptosis Of Colonic Carcinoma Cell Induced By Folic Acid

Background and Objective: Cell apoptosis, is a natural process controlled by aseries of endogenous genes. The block of cell apoptosis is one of the important mechanisms as the same as the abnormality of cell proliferation in carcinogenesis.Therefore, the apoptosis of tumor cell may be a new area in tumor research. It would be anew hot spot to find some drugs, which could induce some malignant cells apoptosis with high efficacy and low toxicity in tumor therapy.Folic acid is one of the dissolvable vitamins Bs. It is associated with the synthesis of adenine, guanine, thymine and proteins including DNA, tRNA compound. What's more, it is also one of the main substrates in some transforming processes of some amino acids convertase and vitamins. The coenzymes of folate are tetrahydrofolate that act asacceptors or donors of one-carbon units during enzyme-promoting rection. Hence, folicacid takes a major part in the cellular metabolism, cellular proliferation and differentiation. Deficiency of folic acid may cause damage, instability and abnormal methylation of DNA, which could bring about in carcinogenesis. Some researches support that folic acid may induce cell apoptosis. Some evidence suggested there was an inverse association between folate intake and colorectal cancer incidence. Folate supplementation protects against subsequent neoplasia. Moreover, folate-mediated cytoprotection may be dose-dependent.Colorectal carcinoma is one of the most malignant tumors. In recent years the incidence of the disease is rising rapidly. In our country its incidence has increased from10/105 to 30/105 comparing with that of thirty years ago. In the range of malignant tumors it has raised from the NO.6 to the NO.3. Many clinic epidemiological studies and human intervention trials have suggested that folic acid may be a cancer chemopreventive agent in the colorectal carcinogenesis. But the firmly mechanism of folic acid is not clarity.In this paper, Human colon cancer cell line, HCT-8, was cultured in vitro and the cell growth and apoptosis were observed with the concentration approaching IC50 detected by MTT method. We investigated the effect of HCT-8 cell apoptosis was examined by hybridization in situ, immunochemistry and gel electrophoresis in order to probe the mechanism of cell apoptosis induced by folic acid may provide theoretical basis for interventional therapy of tumor.Methods:1. The HCT-8 cells cultured in vitro were treated with the different concentration of folic acid for 72 hours. The proper concentration of folic acid was selected by means of MTT method and used to induce the cells apoptosis for assessing the changes of the cell growth suppression.2. Investigation on cell apoptosis by folic acid:The concentration of HCT-8 cell in logarithm growth stage were adjusted to 7X104/ml and cells were incubated in 25ml cultivate bottles. After 24 hours they were matched two groups: one was the experiment group, the other was the control group.2.1. The mRNA expression of cell apoptosis associated bcl-2 and box was examined by hybridization in situ in the depend on dealing group (adding folic acid) and control group (without folic acid).2.2. The protein expression of cell apoptosis associated genes bcl-2 and box was checked with immunochemistry in the depend on dealing group (adding folic acid) and.2.3. Three groups (folic acid-no added, 50μg/ml and 100μg/ml FA) were used toexamine DNA changes of cells after adding folic acid for 72 hours. DNA of's cell(adding folic acid) and contral group (without folic acid) were extracted after folic acid was added for 72 hours. Agarose gel electrophoresis was carried out to analyze the state of DNA fragmentation.Results:1. The result of MTT suggested the adding different concentration of folic acid for 72hours inhibited the cell growth and proliferation in some degree. The folic acid cytotoxicity was increased more obviously with the concentration of folic acid increasing gradually. Its degree was asso...