Up-regulated miR-155-5p promotes cell proliferation, invasion and metastasis in colorectal carcinoma

Background and objective: Emerging evidences indicate that miR-155-5p is associated with some cancer tumorigenesis, but their specific effects on proliferation, invasion and metastasis of colorectal carcinoma (CRC) are still poorly understood. The aim of the study is to investigate miR-155-5p effect on proliferation and invasion metastasis of CRC. Methods: Retrospectively analyzed clinicopathological parameters and fresh tissue samples of 372 colon cancer patients receiving radical surgery. HT-29 cells were transfected with mimics and inhibitors of miR-155-5p, respectively. Real-time reverse transcription-PCR was performed to measure miR-155-5p relative levels of tissues and cells. Results: miR-155-5p expression in cancer group was higher than that in normal group, with statistical differences (P<0.05). miR-155-5p expression was associated with tumor location, tumor grade, TNM staging and distant metastasis (P<0.05 for all parameters). Cell number of mimics group was higher than control group (P<0.01), and that of inhibitor group was lower than control group (P<0.05). Invasion and metastasis effect of mimics group were the highest and those of inhibitor group were the lowest. Conclusions: miR-155-5p expression is up-regulated in most CRC and promotes proliferation, invasion and metastasis of CRC cells. It may play an essential role in tumorigenesis and tumor progression of CRC.