Rhythmic expression of microRNAs in entrained human breast cell lines

Abstract

Circadian rhythms is an essential system for temporal (~24 hours) regulation of molecular processes in diverse organisms. Dysregulation of circadian gene expression has been associated to pathogenesis of various disorders, including hypertension, depression, and diverse cancers. Recently, microRNAs (miRNAs) have been identified as key modulators of gene expression post-transcriptionally, and perhaps involved in circadian clock architecture or their output functions. The aim of the present study is to explore the temporal expression of miRNAs among entrained human breast cell lines. Thus, we evaluated the temporal (28 hours) expression of 2006 miRNAs in breast non- tumorigenic cell line, MCF-10A, and tumorigenic cell lines, MCF-7 and MDA-MB-231 using microarrays technology after serum shock entrainment. We determined miRNAs that exhibit rhythmic fluctuations in each breast cell line, and some of them across two or three cell lines. Afterwards, we confirmed rhythmic profiles exhibited by miR-141-5p, miR- 1225-5p, miR-17-5p, miR-222-5p, miR-769-3p, and miR-548ay-3p in the above cell lines, as well as in ZR-7530 and HCC-1954 using RT-qPCR technology. Our results show that serum shock entrainment in breast cells lines induces rhythmic fluctuations of distinct sets of miRNAs, which have the potential to be related to endogenous circadian clock, but extensive investigation is required to elucidate that connection.