MicroRNA miR–142–3p inhibits breast cancer cell invasiveness and stem cell properties by targeting integrin alpha V, KLF4 and multiple cytoskeletal elements

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Abstract

MicroRNAs are post-transcriptional regulators of gene expression which influence tumorigenesis and tumor progression. miR-142-3p expression is dysregulated in several breast cancer subtypes, but its function at the molecular level is not known in detail. Here, we demonstrate that miR-142-3p is regulated in response to irradiation (2Gy) in human breast cancer cells, suggesting a potential role in the response to radiotherapy. Supported by transcriptomic Affymetrix array analysis and confirmatory investigations at the mRNA and protein level, we demonstrate that overexpression of miR-142-3p in MDA-MB-231, MDA-MB-468 and MCF-7 breast cancer cells leads to downregulation of Integrin- WASL, RAC1, and CFL2, molecules implicated in cytoskeletal regulation and cell motility. ROCK2, IL6ST, KLF4, PGRMC2 and ADCY9 were identified as additional targets in a subset of cell lines. miR- 142-3p overexpressing cells showed decreased Matrigel invasiveness and decreased activity of the stemness-associated enzyme ALDH. Confocal immunofluorescence microscopy, nanoscale atomic force microscopy and digital holographic microscopy revealed an altered actin distribution, a loss of membrane protrusions and a reduced cell volume and size. Interference with additional components of the extracellular matrix environment (Syndecan-1, Hyaluronan) resulted in similar alterations of membrane protrusion formation. Luciferase activation assays confirmed direct miR-142-3p-dependent regulation of the 3’-untranslated region of ITGAV and WASL. siRNA-knockdown of ITGAV and WASL resulted in a significant reduction of cellular invasiveness, highlighting their contribution to the invasion phenotype. While WASL-knockdown significantly reduced the number of membrane protrusions compared to controls, knockdown of ITGAV resulted in a decreased cell volume. Our data identify ITGAV, WASL, and several additional cytoskeleton- associated molecules as novel invasionpromoting targets of miR-142-3p in breast cancer. Whether regulation of the pluripotency-associated transcription factor KLF4 and alterations in ALDH1 activity are linked to alterations in matrixdependent signaling, or due to direct regulation by miR-142-3p is currently under investigation.

Speakers from the University of Münster

Götte, Martin

Department of Gynecology and Obstetrics

Projects the talk is about

Matrix glycans as multifunctional pathogenesis factors and therapeutic targets in cancer (GLYCANC) Duration: 01/07/2015 - 30/06/2019 Funded by: EC H2020 - Marie Skłodowska-Curie Actions - Research and Innovation Staff Exchange Type of project: EU-project hosted at University of Münster

Publications referred to in the talk

MicroRNA MIR-142-3p Inhibits Breast Cancer Cell Invasiveness by Synchronous Targeting of WASL, Integrin Alpha V, and Additional Cytoskeletal Elements Schwickert A., Weghake E., Brüggemann K., Engbers A., Brinkmann B., Kemper B., Seggewiß J., Stock C., Ebnet K., Kiesel L., Riethmüller C., Götte M. (2015) In: PloS one, 10(12). doi:10.1371/journal.pone.0143993 Research article (journal) | Peer reviewed | Published