MYH9Expression And Biological Effect In Human Colon Canrinomas

Objective:Colon carcinoma is one of the most common malignant tumors, but the pathogenesis is still not very clear. Further reserch of the pathogenesis of colon cancer will be important for the early diagnosis, the improvement of rate of cure and life quality of the patients. MYH9may contribute to the initiation and progression in colon cancer, but the mechanism is still unclear.Methods:The samples from60patients with sporadic colon cancer were obtained. The clinical data of patients, including age, gender, primary tumor location, tumor staging and size, histological pattern, degree of differentiation, were analyzed and correlated. The expression of MYH9mRNA was detected in both colon cancer and their paired normal control tissue by real-time PCR. The level of MYH9protein was detected in both colon cancer and their paired normal control tissue by western bolt. The data from western blot and real-time PCR were correlated and statistically analysed with the clinical data.Two target sequences were selected according to MYH9mRNA sequence, then two pairs of oligonucleotide sequences according to the target sequences were designed and synthesized. The lentivirus RNAi vectors were constructed succesfully. These vectors were cotransfected with Lentiviral packaging Mix into293FT cells for the package of lentiviral particles. Then the lentiviral particles were transfected into HCT-8and SW480cell lines. The expression of MYH9was detected by Real-time PCR and Western blot. The effects of the cells transfected with lentiviral particles on the cell proliferation, cell growth curve and migration were evaluated by using MTT and wound healing assay.Results:MYH9mRNA and protein expressed in both normal and colon cancer tissues. The clinical data from60patients with colon cancer showed that MYH9mRNA and protein expression in colon cancer is significantly different from that of the normal tissues (Respectively p <0.0001, p=0.0313). Immunohistochemistry results showed that, MYH9in colon cancer tissues was significantly higher than the control group. Compared to proximal colon, the MYH9expression in the distal colon was higher, and the difference was significant, P=0.01001, while the MYH9expression in normal controls showed no significant difference. The MYH9expression level in metastasis occurred tumors (stage Ⅲ and Ⅳ,) was significantly higher than those without metastasis of tumors (stage Ⅰ and Ⅱ,), P=0.0008.To explore the possible role of MYH9in the development of colon cancer, two RNAi lentivirusal particles for MYH9different sites were obtained. There is no evident change in the level of MYH9mRNA and protein in control lentivirusal particles, but the HCT-8and SW480cells transfected with these RNAi lentivirusal particles significantlly decreased. Cell.growth curve analysis and MTT assay indicated that HCT-8and SW480cells, which were transfected with MYH9RNAi virius, proliferated more slowly than the cells transfected with control virius. Moreover, the cell number of HCT-8and SW480transfected with MYH9RNAi virius migration were less than the control.Conclusions:The expression of MYH9mRNA and protein were higher in colon cancer tissues than that in paired normal control tissues. The MYH9expression in colon cancer is significantly correlated with primary tumor location and staging, implying that MYH9might play a role in the ivasion and metastasis of colon carcinoma. RNAi MYH9could slow down the growth, proliferation and migration of the colon cancer cells.