The investigation of target gene of antisense oligonucleotides (ASOs) against microRNA-21 in colorectal carcinoma cells in vivo

To further elucidate the potential molecular mechanism through which down-regulated the expression level of miR-21 affected the growth of colorectal carcinoma cells, we used TargetScan and MIRDB software to screen out 16 genes, and 5 genes were up-regulated, putative target genes of miR-21 including PDZD2, DUSP8, B3GAT2, STAG2 and CCL1, which were closely correlated with proliferation, apoptosis and metastasis in tumor cells according to previous literatures. ASOs against miR-21 in CRC cells in vivo altered the expression of target gene, for preparation of subcutaneous xenograft model, cells were subcutaneously implanted into the right flanks of nude mice at 3.5×10e6 SW620 cells density (n=20). Then 7 days after tumor cells inoculation with confirmation of successful maturation of tumors, 20 mice were divided randomly into two groups (10 mice per group). The 100μg plasmid of p-miR-21-ASOs or p-Cont was given locally by direct injection into the tumor tissues of nude mice at four times every three days.