Effect Of Models Of Superoxide Dismutase On Human Hepatoma Cell Line

Superoxide dismutase (SOD), a kind of enzyme containing copper, manganese or iron etc, exists broadly in organisms. It can catalyze the superoxide anion free radical (O-2) to carry through reversible reactions and significantly prevent organisms from being damaged by the toxicity of O-2. Similar changes of the activity and the concentration of SOD have been detected in aging, inflammation, cancer, irradiation diseases, self-immunity diseases and some infectious diseases etc. in considerable studies that both the activity and the concentration of SOD in human decrease gradually as the diseases happening and worsening, and raise to normal level as diseases alleviate. Therefore, the low activity of SOD may be used as one of characteristic of some diseases. Nowadays, more attention has been paid to the issue whether the intake of extrinsic SOD can protect organisms from diseases and even cure diseases. SOD, however, as a kind of molecules with high molecule-weight and short half-life, cannot permeate cell membranes smoothly and often cause the body-excluding reaction in clinical application so that its application as a clinical medicine has been restricted greatly. Hence, scientists of both biology and chemistry have synthesized low molecule-weight metal compounds containing copper, manganese or cobalt etc. which have similar structures with the active center of crude SOD by means of chemosynthesis and token. The synthesized product may overcome disadvantages of natural SOD and can be used in clinic finally.To detect the anti-cancer efficacies of model SOD mimics Mn(EDTB) (AC) and Cu2C21Nl4H27Cl13, human buccal cells, hepatoma SSMC-7721 cell lines, and embryo liver L-02 cell lines were used as targets to carry out the following experiments. (1) Comet assay. It was done to detect the effect of the MSOD on human buccal cells and find out the secure dosages to normal cells. (2) Protracting the growth curves of the objects. The protracted curves reflect the effects of different concentrations of the MSOD. (3) MTT assay: to examine the inhibition effect of the MSOD on SSMC-7721 cell lines. (4) Comet assay and DNA agarose gel electrophoresis. To explore effects of both the SOD mimics on the DNA of SSMC-7721 cell lines and L-O2 cell lines. (5) To detect the effects of MSOD on the cell cycle of objects by Flow cytometry. (6) Detection of intracellular and extracellular activity of SOD. This assay was carried out to find out changes of the SOD activity before and after adding the drug. The research results of the above experiments show that: ?There was no damage to the human buccal cells, when the added concentration of Cu2C21Nl4H27Cl13 was less than 100 jig/ml. (2) The protracted growth curve and data from the MTT assay reflected that both the SOD mimics had inhibition effect on the SSMC-7721 cell lines which increased with the increase of the effect time and concentration. But comparatively, their effects on L-02 cell lines were much less. (3) The DNA samples from the hepatoma cells treated with the drug presented four well-regulated ladders, while the control sample presented only one ladder in the DNA agarose gel electrophoresis. The result of comet assayshowed that the mimics exert obvious damage on the DNA of the SSMC-7721 cell lines as well. But the DNA samples from L-02 cell lines presented only one ladder, either the drug-added group or its control. That determines that the mimics have no effect on the DNA of L-02 cell lines. (4) The hepatoma cells treated with different concentrations of the mimic Mn(ED TB) (AC) 12 hours in G0/G1 phases increased, while those in S phase declined evidently. (5) The activity of extracellular SOD of the hepatoma cells declined after being treated with the MSOD, while that of the intracellular increased. Total concentration of the protein in both the suspension of the culture medium and inside the cells decreased. From the research results we can conclude that the SOD mimics used in this research can alter the redox level and disrupt the DNA replication in the SSMC-7721 cell lines...