Arp2/3 inhibition induces amoeboid-like protrusions in MCF10A epithelial cells by reduced cytoskeletal-membrane coupling and focal adhesion assembly

PLoS One. 2014 Jun 26;9(6):e100943. doi: 10.1371/journal.pone.0100943. eCollection 2014.

Abstract

Here we demonstrate that Arp2/3 regulates a transition between mesenchymal and amoeboid protrusions in MCF10A epithelial cells. Using genetic and pharmacological means, we first show Arp2/3 inhibition impairs directed cell migration. Arp2/3 inhibition results in a dramatically impaired cell adhesion, causing deficient cell attachment and spreading to ECM as well as an 8-fold decrease in nascent adhesion assembly at the leading edge. While Arp2/3 does not play a significant role in myosin-dependent adhesion growth, mature focal adhesions undergo large scale movements against the ECM suggesting reduced coupling to the ECM. Cell edge protrusions occur at similar rates when Arp2/3 is inhibited but their morphology is dramatically altered. Persistent lamellipodia are abrogated and we observe a markedly increased incidence of blebbing and unstable pseuodopods. Micropipette-aspiration assays indicate that Arp2/3-inhibited cells have a weak coupling between the cell cortex and the plasma membrane, and suggest a potential mechanism for increased pseudopod and bleb formation. Pseudopods are not sensitive to reduced in formin or myosin II activity. Collectively, these results indicate that Arp2/3 is not necessary for rapid protrusion of the cell edge but plays a crucial role in assembling focal adhesions required for its stabilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin-Related Protein 2-3 Complex / antagonists & inhibitors
  • Actin-Related Protein 2-3 Complex / genetics
  • Actin-Related Protein 2-3 Complex / metabolism*
  • Actins / metabolism
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Cell Movement / drug effects
  • Cell Movement / genetics
  • Cell Surface Extensions
  • Cytoskeleton / metabolism*
  • Epithelial Cells / metabolism*
  • Extracellular Matrix / metabolism
  • Focal Adhesions / drug effects
  • Focal Adhesions / metabolism*
  • Humans
  • Myosin Type II / metabolism
  • Organoselenium Compounds / pharmacology
  • Organosilicon Compounds / pharmacology
  • RNA Interference
  • RNA, Small Interfering / genetics

Substances

  • Actin-Related Protein 2-3 Complex
  • Actins
  • CK-869
  • Organoselenium Compounds
  • Organosilicon Compounds
  • RNA, Small Interfering
  • Myosin Type II

Grants and funding

Packard Foundation Grant. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.