The Effects Of YWHAZ Gene On Colon Cancer HCT-8Cells And Tumor Proliferation

With the improvement of people’s living standards, the incidence of colon canceris increasing and has been the fourth cause of cancer-related death, which is a greatthreat to health. In the recent years, the studies on the colon tumor animal model andmolecular etiology have become a research hotspot. YWHAZ is a member of the14-3-3gene family, which is associated with the formation of tumor. It has been foundthat the protein14-3-3ζ encoded by YWHAZ expresses abnormally in many types oftumor, such as gastric cancer, lung cancer and liver cancer. Over-expression ofYWHAZ could lead to tumorigenesis by inhibiting the expression of tumor suppressorgenes p53. By eatablishing colon tumor HCT-8nude mouse model and using si-RNAor over-expression of YWHAZ, we studied potential effects of YWHAZ on theproliferation of colon cancer. Our results might provide a theoretical base for YWHAZas a target in therapeutic measures of colon cancer.Tumor in nude mice implanted animal model was used in the study. RNAinterference and gene over-expression vectors were transfected in HCT-8cell and atransplantation tumor model were used in this study. From the results of real-timePCR, it was found that in the RNA interference plasmid transfection group(pGPU6/GFP/Neo-YWHAZ-792, pGPU6/GFP/Neo-YWHAZ-733,pGPU6/GFP/Neo-YWHAZ-612, pGPU6/GFP/Neo-YWHAZ-505) mRNA expression level incolon cancer HCT-8cells decreased compared with that in the negative group(P<0.05).In the over-expression plasmid transfection group (PEF1α-IRES-DSRED-Express2-YWHAZ), mRNA expression level of YWHAZ gene increased significantlycompared to the blank control group (PEF1α-IRES-DSRED-Express2)(P<0.05). Andthe mRNA expression level of the negative control plasmid transfection group(pGPU6/GFP/Neo-shNC) had no significant difference with the blank control group.The result of Western-blotting showed that expression quantity of protein14-3-3ζ decreased in the RNA interference plasmid transfection groups whereas increased inthe over-expression plasmid transfection groups; and there was no significantdifference between negative control groups and blank control group. At the same time,MTT was used to study the changes of cell proliferation in each groups. The resultshowed that the cell proliferation of the RNA interference group was slower than theblank control group (P<0.05), while cell proliferation of the over-expression groupwas faster (P<0.05), and there was no significant difference between negative controlgroup and blank control group. The mice model of transplanted tumor was establishedsuccessfully with a subcutaneous implant. The tumor growth in nude mice injectedwith the RNA interference plasmid was significantly less than the control group(P<0.05) and the inhibition rate was57.28%, while that in nude mice injected withoverexpression plasmid was significantly higher than the control group (P<0.05).