Expression of miRNA-1 in colorectal cancer tissues and its effect on proliferation and invasion of colorectal cancer DLD1 cells / 肿瘤研究与临床

ABSTRACT

Objective To investigate the expression of miRNA-1 (miR-1) in colorectal cancer (CRC) tissues and its effect on proliferation and invasion of CRC cells in vitro as well as its mechanism. Methods A total of 180 CRC tissues from the hospitalized patients who underwent excision surgery and 114 adjacent cancer tissues in the Affiliated Cancer Hospital of Shanxi Medical University between June 2015 and December 2015 were collected. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-1 in 58 cases of CRC tissues and adjacent cancer tissues. Immunohistochemistry was used to detect the expression of stromal cell-derived factor-1 (SDF-1) protein in 122 CRC tissues and effect of overexpression or knockdown of miR-1 on the proliferation, colony formation and invasiveness of DLD1 cells, respectively. Western blot was used to determine the effect of overexpression or knockdown of miR-1 on the expression of SDF-1 in DLD1 cells. Results RT-qPCR results showed that the expression of miR-1 in CRC tissues was decreased compared with the corresponding adjacent cancer tissues (the relative expression level ratio < 0.5), and the low expression rate of miR-1 in CRC was 82.8％ (48/58). Immunohistochemistry results showed that the positive expression rate of SDF-1 in CRC tissues was higher than that in adjacent cancer tissues [81.1％ (99/122) vs. 8.9％ (5/56), χ2= 82.415, P< 0.01]. Cell function experiment showed that, compared with the control group, the proliferative activity of DLD1 cells that transfected miR-1 mimics was decreased, meanwhile, the colony formation, invasion and SDF-1 expression were reduced (P< 0.05). The proliferative activity, colony formation, invasion and SDF-1 expression in DLD1 cells that transfected miR-1 inhibitor were improved compared with those in the control group (P< 0.05). Conclusions The expression of miR-1 in CRC tissues is low and it may act as a tumor suppressor gene through affecting proliferation and invasive potential of CRC cells by regulating the expression of SDF-1.