Project description:In the recent past, the impact of isomiR expression changes in cancer has gained increasing interest. Here, we stably overexpress pre-miR-1307, a pre-miRNA which is frequently upregulated in cancer, and assess the effect on isomiR expression. While we see robust and significant upregulation of the canonical form miR-1307-3p|0 and its abundant 5'isomiR miR-1307-3p|1, as well as of the canonical miR from the 5p arm (miR-1307-5p|0), the overexpression of pre-miR-1307 did not lead to global alterations in isomiR expression patterns. These data validate the suitability of our model cell line for the analysis of the effects of joint upregulation of miR-1307-3p|0, -3p|1 and -5p|0.
Project description:MiRNAs have been shown to alter both protein expression and secretion in different cellular contexts. By combining in vitro, in vivo and in silico techniques, we demonstrated that overexpression of pre-miR-1307 reduced the ability of breast cancer cells to induce endothelial cell sprouting and angiogenesis. However, the molecular mechanism behind this and the effect of the individual mature miRNAs derived from pre-miR-1307 on protein secretion and is largely unknown. Here, we overexpressed miR-1307-3p|0, -3p|1 and 5p|0 in MDA-MB-231 breast cancer cells and assessed the impact of miRNA overexpression on protein secretion by Mass Spectrometry. Unsupervised hierarchical clustering revealed a distinct phenotype induced by overexpression of miR-1307-5p|0 compared to the controls and to the 5’isomiRs derived from the 3p-arm. Together, our results suggest different impacts of miR-1307-3p and miR-1307-5p on protein secretion which is in line with our in vitro observation that miR-1307-5p, but not the isomiRs derived from the 3p-arm reduce endothelial cell sprouting in vitro. Hence these data support the hypothesis that miR-1307-5p is at least partly responsible for impaired vasculature in tumors overexpressing pre-miR-1307.
