Effects of miR-376 family miRNAs on CHRNA5 depleted MCF7 cell line model and co-culture competition studies

Abstract

Cholinergic receptor nicotinic alpha 5 (CHRNA5) is a ligand-gated ion channel and one of the subunits of nicotinic acetylcholine receptors. Role of CHRNA5 in tumorigenesis has been initially shown in the lung tissue in which higher CHRNA5 expression has been significantly correlated with worse prognosis in lung cancer. In addition, our laboratory members recently shown that CHRNA5 depletion in breast cancer cell line MCF7 is antiproliferative (TUBITAK 111T316). In present study, effects of CHRNA5 depletion on miRNA expression profile were investigated and a significant decrease in the expressions of two members of the miR-376 family miRNAs, miR-376a-3p and miR-376c-3p, were identified. To test the effects of these two miRNAs, mimics were used in combination with CHRNA5 depletion on MCF7 cell line model. To investigate the synergism and/or antagonism of miR-376a mimic with CHRNA5 siRNA treatment a microarray study was performed and the signaling pathways involved were identified. Expressions of genes of interest were tested with RT-qPCR for both miRNAs. In addition, the effects of rescue on the cell phenotype and viability were also studied by using phalloidin staining and MTT experiments, respectively. Next a co-culture-based competition assay was developed using MCF7 cell lines expressing different fluorescent molecules to assess competition by both flow cytometer and fluorescent imaging. In summary, the results revealed that combinational treatments of si-CHRNA5 together with the miRNA mimics of two members from miR-376 family revealed enhancement of the antitumor effects. This study has been supported by TUBITAK (grant no. 114S367).