Micro-RNA451Inhibits Growth Of Subcutaneous Implantation Tumor Of Human Colorectal Cancer In Nude Mice And The Probably Mechanism

Objective: To explore the effects of microRNA451(miR-451)on thegrowth of implanted subcutaneous tumors in human colorectaltumor-bearing nude mice，and to investigate the probably mechanism ofmiR-451as a new tumor suppressor in vivo．Methods: Eighty nude mice were randomized into3groups，SW-620-451group、SW-620-NC group and SW-620group，six mices everygroup.The animal model of subcutaneous implantation tumor in nude micewas established by corresponding iniecting of6x106SW-620-451cells(transfected with miR-451agomir)、SW-620-NC(transfected with agomir Nonsense Control sequence)cells and SW-620cells subeutaneous1y．The mice of three groups were respectively injectedwith miRNA451agomir，miRNA451agomir Nonsense Control agomir andsaline twice a week.Compare the tumor growth in each group and calculatethe tumor inhibition rate. The mice was killed in4weeks.The expression of c-myc in each group were examined by immunohistochemistry andWestern-blotting respectively．Results: Every nude mice has tumor formation after6days ofsubcutaneous inoculation with a tumor formation rate of100％．The tumorgrowth rate of SW-620-451group was significantly lower than the othertwo groups（p＜0.05）.At the endpoint time of30th days．The averagetumor volume of SW-620-451group was smaller than those ofSW-620-NC and SW-620groups（[0.95±0.13）cm3vs（2.25±0.50）cm3and（2.46±0.59）cm3，p<0．05]．The average tumor weight of SW-620-451group was lighter than those of SW-620-NC and SW-620groups（[1.15±0.13）g v（s2.59±0.46）g and (2.76±0.44)g，p<0．05]．The expressionof c-myc in SW-620-451group was decreased compared with those ofSW-620-NC groups and SW-620groups.（p<0．05）Conclusion: The high expression of miR-451can effectively inhibitthe growth of tumor in human colorectal tumor-bearing nude mice and themechanism maybe related to the decrease expression of c-myc protein...