Deregulation of miR-126 expression in colorectal cancer pathogenesis and its clinical significance

• Low miR-126 expression was associated with pathological features, MSI and staging.
• Low miR-126 expression was associated with poorer patients’ survival in CRC.
• Many patients had similar levels of miR-126 expression in primary cancer and cancer metastases.
• Induced miR-126 expression reduces cancer proliferation & increases apoptosis.
• SW480+miR-126 cells showed reduced BCL-2 and increased P53 protein expression.

In this study, we investigated the expression profiles and clinicopathological significance of miR-126 in large cohort of patients with colorectal cancers as well the cellular repercussions of miR-126 in colon cancer cells along with its targets in-vitro. Down regulation of miR-126 expression was associated with histological subtypes, peri-neural tumour infiltration, microsatellite instability and pathological staging of colorectal cancers (p<0.05). Low miR-126 expression was also associated with poorer survival in patients with colorectal cancer. Analysis of matched tissues from the same patient revealed that approximately 70% of the tested patients had similar levels of expression of miR-126 in primary cancer and cancer metastases in both lymph node and distant metastases. In addition, induced overexpression of miR-126 showed reduced cell proliferation, increased apoptosis and decreased accumulation of cells in the G0–G1 phase of the colon cancer cells. Furthermore, SW480+miR-126 cells showed reduced BCL-2 and increased P53 protein expression. To conclude, deregulation of miR-126 in colorectal cancer at the tissue and cellular levels as well as its correlation with various clinicopathological parameters confirm the cancer suppressive role of miR-126 in colorectal cancer.