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@ARTICLE{Li:180198,
author = {X. Li$^*$ and B. Michels$^*$ and O. E. Tosun$^*$ and J.
Jung$^*$ and J. Kappes$^*$ and S. Ibing$^*$ and N. B.
Nataraj and S. Sahay and M. Schneider$^*$ and A. Wörner$^*$
and C. Becki$^*$ and N. Ishaque and L. Feuerbach$^*$ and B.
Heßling$^*$ and D. Helm$^*$ and R. Will$^*$ and Y. Yarden
and K. Müller-Decker$^*$ and S. Wiemann$^*$ and C.
Körner$^*$},
title = {5'isomi{R}-183-5p|+2 elicits tumor suppressor activity in a
negative feedback loop with {E}2{F}1.},
journal = {Journal of experimental $\&$ clinical cancer research},
volume = {41},
number = {1},
issn = {0392-9078},
address = {London},
publisher = {BioMed Central},
reportid = {DKFZ-2022-01167},
pages = {190},
year = {2022},
note = {#EA:B050#LA:B050#},
abstract = {MicroRNAs (miRNAs) and isomiRs play important roles in
tumorigenesis as essential regulators of gene expression.
5'isomiRs exhibit a shifted seed sequence compared to the
canonical miRNA, resulting in different target spectra and
thereby extending the phenotypic impact of the respective
common pre-miRNA. However, for most miRNAs, expression and
function of 5'isomiRs have not been studied in detail yet.
Therefore, this study aims to investigate the functions of
miRNAs and their 5'isomiRs.The expression of 5'isomiRs was
assessed in The Cancer Genome Atlas (TCGA) breast cancer
patient dataset. Phenotypic effects of miR-183
overexpression in triple-negative breast cancer (TNBC) cell
lines were investigated in vitro and in vivo by quantifying
migration, proliferation, tumor growth and metastasis.
Direct targeting of E2F1 by miR-183-5p|+2 was validated with
a 3'UTR luciferase assay and linked to the phenotypes of
isomiR overexpression.TCGA breast cancer patient data
indicated that three variants of miR-183-5p are highly
expressed and upregulated, namely miR-183-5p|0,
miR-183-5p|+1 and miR-183-5p|+2. However, TNBC cell lines
displayed reduced proliferation and invasion upon
overexpression of pre-miR-183. While invasion was reduced
individually by all three isomiRs, proliferation and cell
cycle progression were specifically inhibited by
overexpression of miR-183-5p|+2. Proteomic analysis revealed
reduced expression of E2F target genes upon overexpression
of this isomiR, which could be attributed to direct
targeting of E2F1, specifically by miR-183-5p|+2. Knockdown
of E2F1 partially phenocopied the effect of miR-183-5p|+2
overexpression on cell proliferation and cell cycle. Gene
set enrichment analysis of TCGA and METABRIC patient data
indicated that the activity of E2F strongly correlated with
the expression of miR-183-5p, suggesting transcriptional
regulation of the miRNA by a factor of the E2F family.
Indeed, in vitro, expression of miR-183-5p was regulated by
E2F1. Hence, miR-183-5p|+2 directly targeting E2F1 appears
to be part of a negative feedback loop potentially
fine-tuning its activity.This study demonstrates that
5'isomiRs originating from the same arm of the same
pre-miRNA (i.e. pre-miR-183-5p) may exhibit different
functions and thereby collectively contribute to the same
phenotype. Here, one of three isomiRs was shown to
counteract expression of the pre-miRNA by negatively
regulating a transcriptional activator (i.e. E2F1). We
speculate that this might be part of a regulatory mechanism
to prevent uncontrolled cell proliferation, which is
disabled during cancer progression.},
keywords = {Cell cycle (Other) / E2F1 (Other) / IsomiRs (Other) /
MiR-183-5p (Other) / MicroRNAs (Other) / Triple-negative
breast cancer (Other)},
cin = {B050 / B330 / W120 / W420},
ddc = {610},
cid = {I:(DE-He78)B050-20160331 / I:(DE-He78)B330-20160331 /
I:(DE-He78)W120-20160331 / I:(DE-He78)W420-20160331},
pnm = {312 - Funktionelle und strukturelle Genomforschung
(POF4-312)},
pid = {G:(DE-HGF)POF4-312},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:35655310},
doi = {10.1186/s13046-022-02380-8},
url = {https://inrepo02.dkfz.de/record/180198},
}