Influence Of Regional Chemotherapy On Cell Cycle Progress And Regulation In Human Colorectal Cancer Cell Line

Colorectal cancer is one of the most common human malignant tumor in the world, especially in the West. The Regional chemotherapy is a new effective treatment to the colorectal cancer .High concentrated Drugs were infused into the solid tumors ,which directly lead to killing cancer cells, relieving the clinical symptoms, as inhibiting the development and metastasis of carcinoma. But the biological mechanism of this therapy has not been clearly revealed.In order to explore the mechanism of regionalchemotherapy in colorectal cancer ,we used the technique ofcell cycle synchronization to research the influence of 5-FU(the chief drugs in regional chemotherapy) on Gl/S phaseprogress and cell cycle regulation in CA- II cell line ofhuman colorectal cancer, and to discuss the dose-efficiency relation between different concentrations of drugs and tumor killing effect .The changes of transcription in cell cycle regulation pathway p16/cyclinDl/CDK4/Rb were also evaluated by the assay of RT-PCR.The method and results: colorectal cancer cells which used TdR and N2O double blocking synchronization were treated by 5-Fu in control group 0.1mmoI/L 1.0mniol/L and 10mmol/L group, the LI incorporation index of 3H-TdR was obviously increased in ll-13h, 12-14h 12-14h 13-15h after M phase release. P16 cyclinDl CDK4 Rb gene fragments were abstracted and amplificated by RT-PCR, then the Bandleader 3.0 gel analysis software was used for bands analysis. The ratios of integral value of area of target gene bands and internal control P 2-MG was as comparative parameter. The results showed:p16 value was 0.6562 1.3695 1.7325 and 2.589 in control group., 0.1mmol/L 1.0mmol/L and 10mmol/L group. There was significant difference in each groups,(p<0.01);groups, (p<0. 01) ; cycliDl value was 2. 9025 2. 0352 1. 6235 and 0.8665 in four groups mentioned above, which was significant difference in each groups, (p<0.01); while the CDK4 and Rb value was no significant difference in four groups, (p>0.05).Conclusion: 1. The incorporation peak of 3H-TdR in colorectal cancer cell was prolonged with concentration of 5-Fu increasing.2. After the colorectal cancer cell CA-II were pre-treated by 5-Fu, the time limit of Gl/S phase were obviously delayed, and cell cycle progress were blocked, and cell malignant hyperplasia were inhibited.3. The cell cycle in Gl/S phase were arrested by certain concentration of 5-Fu, which in p16/cyclinDl/CDK4/Rb regulation pathway, there was maybe correlation between in creasing transcription of p16 gene and decreasing transcription of cycIinDl gene, but no relation transcription inCDK4 Rb.4. The high concentration of 5-Fu had more cycle inhibitoryaction on colorectal cancer cell.