MiR-199-3p replacement affects E-cadherin expression through Notch1 targeting in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the second cause of cancer-related mortality worldwide and is associated with poor prognosis, due to a high recurrence rate after curative treatments and a drug resistance phenotype. In this scenario, the identification of innovative and effective therapeutic strategies is an unmet clinical need. The safety and efficacy of microRNA (miRNA) mediated approaches in preclinical models and clinical trials have been widely described in cancer. MicroRNA-199a downregulation is a common feature of HCC where its reduced expression contributes to mTOR and c-Met pathways activation. Notch1 activation is also a common event in HCC, influencing epithelial-to-mesenchymal transition, tumor invasion and recurrence at least in part through E-cadherin regulation. Here we identified a negative correlation between miR-199a-3p and Notch1 or E-cadherin protein levels in HCC patients and demonstrated that miR-199a-3p regulates E-cadherin expression through Notch1 direct targeting in in vitro models. Moreover, we showed that a strong correlation exists between miR-199a-5p and miR-199a-3p in HCC specimens and that miR-199a-5p contributes to E-cadherin regulation as well, underlying the complex network of interaction carried out by miR-199a and its influence on tumor aggressiveness. In conclusion, our findings suggest the restoration of miR-199a-3p physiologic levels as a possible therapeutic strategy for the treatment of HCC.