MicroRNA-196b-5p is a prognostic factor in colorectal cancer patients and influences cancer cell migration and metastases formation through regulation of HOXB7 and GalNT5

Background: MicroRNA-196b-5p (miR-196b-5p) has been previously involved in carcinogenesis, though its role in colorectal cancer (CRC) patients and biology remains controversially. In our current study, we systematically explored the clinical significance and biological relevance of miR-196b-5p, as well as the underlying molecular mechanisms regulated by miR-196b-5p in colorectal cancer. Methods: In this study, we measured miR-196b-5p expression by quantitative RT-PCR and explored its prognostic value in two independent patient cohorts of 292 CRC patients. In a panel of CRC cell lines, using transient and stable gain and loss of function experiments, we evaluated the impact on in vitro proliferation, chemo-sensitivity and migration/invasion as well as in vivo metastases-formation. The molecular mode of action was characterized by mRNA transcriptome profiling, target prediction tools, luciferase-interaction assays, and pheno-copy gene knock-down experiments for potential target genes. Results: Our clinical data indicate that low levels of miR-196b-5p in CRC are significantly associated with metastatic disease and poor patient outcome in both independent cohorts (p<0.05). A loss of function of miR-196b-5p led to increased cancer cell migration/invasion and metastases formation, which can be partly explained by direct interaction with HOXB7 and GalNT5 mRNA, which both of them influence CRC cell migration. Conclusion: In conclusion, our data suggest that low levels of miR-196b-5p are associated with poor prognosis in CRC. MiR-196b-5p has an effect on CRC progression through genes important for cancer cell migration and metastases. three biological replaicates of stably transduced HCT116 miR-196b overexpressing cells or empty vector transtuced cells as control cells