NF‐κB inhibition reverses acidic bile‐induced miR‐21, miR‐155, miR‐192, miR‐34a, miR‐375 and miR‐451a deregulations in human hypopharyngeal cells

We previously demonstrated that acidic bile activates NF‐κB, deregulating the expression of oncogenic miRNA markers, in pre‐malignant murine laryngopharyngeal mucosa. Here, we hypothesize that the in vitro exposure of human hypopharyngeal cells to acidic bile deregulates cancer‐related miRNA markers that can be reversed by BAY 11‐7082, a pharmacologic NF‐κB inhibitor. We repetitively exposed normal human hypopharyngeal primary cells and human hypopharyngeal keratinocytes to bile fluid (400 μmol/L), at pH 4.0 and 7.0, with/without BAY 11‐7082 (20 μmol/L). We centred our study on the transcriptional activation of oncogenic miR‐21, miR‐155, miR‐192, miR‐34a, miR‐375, miR‐451a and NF‐κB‐related genes, previously linked to acidic bile‐induced pre‐neoplastic events. Our novel findings in vitro are consistent with our hypothesis demonstrating that BAY 11‐7082 significantly reverses the acidic bile‐induced oncogenic miRNA phenotype, in normal hypopharyngeal cells. BAY 11‐7082 strongly inhibits the acidic bile‐induced up‐regulation of miR‐192 and down‐regulation of miR‐451a and significantly decreases the miR‐21/375 ratios, previously related to poor prognosis in hypopharyngeal cancer. This is the first in vitro report that NF‐κB inhibition reverses acidic bile‐induced miR‐21, miR‐155, miR‐192, miR‐34a, miR‐375 and miR‐451a deregulations in normal human hypopharyngeal cells, suggesting that acidic bile‐induced events are directly or indirectly dependent on NF‐κB signalling.