Down-regulation of microRNA-21 expression inhibits the growth of human colon carcinoma SW620 cells in nude mice / 肿瘤

ABSTRACT

Objective: To investigate the effect of microRNA-21 (miR-21) expression down-regulated by antisense oligonucleotides (ASOs) on the growth of human colon carcinoma SW620 cells in nude mice. Methods: Firstly, the nude mouse model of human colon carcinoma cell line SW620 was established. Then the recombinant plasmid p-miR-21-ASOs or the control plasmid p-Cont was locally injected into tumor tissues (once every 4 days), and the tumor growth was observed. On the 5th day after the last injection, all of mice were sacrificed, and the tumor tissues were removed and measured. Then the histomorphology of tumor tissues was observed by HE staining assay. The apoptosis of tumor cells was analyzed by TUNEL assay. The expression of Ki-67 proliferation nuclear antigen was measured by immunofluorescence assay. Furthermore, the expression levels of mature miR-21, as well as cyclin-dependent kinase (CDK) 2, CDK3, CDK4 and CDK6 were detected by real-time fluorescent quantitative PCR. And the expressions of phosphorylated protein kinase B (p-Akt) and phosphorylated extracellular regulated protein kinase (p-ERK) were analyzed by Western blotting. Results: Compared with p-Cont group, the xenograft tumors in p-miR-21-ASOs group grew slowly (P < 0.05), and the weight of tumor tissues was significantly reduced (P < 0.01). Meanwhile, there were large areas of necrosis in tumor tissues in p-miR-21- ASOs group. The expression level of miR-21 in tumor tissues was significantly decreased after p-miR-21-ASOs injection (P < 0.01). Moreover, the expression of Ki-67 in tumor tissues was significantly down-regulated (P < 0.01), and the relative number of apoptosis cells increased obviously (P < 0.05) in p-miR-21-ASOs group. Furthermore, the relative expression levels of CDK2, CDK3, CDK4, CDK6, p-Akt and p-ERK were significantly down-regulated in p-miR- 21-ASOs group as compared with p-Cont group (all P < 0.05). Conclusion: Down-regulation of miR-21 expression by ASOs can significantly inhibit the growth of human colon carcinoma SW620 cells in nude mice, indicating that miR-21 may be a potential target for gene therapy of colon cancer.