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Biochem Biophys Res Commun. 2018 Jun 7;500(3):557-563. doi: 10.1016/j.bbrc.2018.04.085. Epub 2018 Apr 23.

Cdc42-dependent modulation of rigidity sensing and cell spreading in tumor repopulating cells.

Author information

1
Department of Mechanical Engineering and Energy Processes, Southern Illinois University Carbondale, Carbondale, IL 62901, USA. Electronic address: farhan.chowdhury@siu.edu.
2
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
3
Howard Hughes Medical Institute, Johns Hopkins University, Baltimore, MD 21205, USA.
4
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
5
Department of Mechanical Engineering and Energy Processes, Southern Illinois University Carbondale, Carbondale, IL 62901, USA.
6
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
7
Howard Hughes Medical Institute, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21205, USA.

Abstract

Recently, a robust mechanical method has been established to isolate a small subpopulation of highly tumorigenic tumor repopulating cells (TRCs) from parental melanoma cells. In order to characterize the molecular and mechanical properties of TRCs, we utilized the tension gauge tether (TGT) single-molecule platform and investigated force requirements during early cell spreading events. TRCs required the peak single molecular tension of around 40 pN through integrins for initial adhesion like the parental control cells, but unlike the control cells, they did not spread and formed very few mature focal adhesions (FAs). Single molecule resolution RNA quantification of three Rho GTPases showed that downregulation of Cdc42, but not Rac1, is responsible for the unusual biophysical features of TRCs and that a threshold level of Cdc42 transcripts per unit cell area is required to initiate cell spreading. Cdc42 overexpression rescued TRC spreading through FA formation and restored the sensitivity to tension cues such that TRCs, like parental control cells, increase cell spreading with increasing single-molecular tension cues. Our single molecule studies identified an unusual biophysical feature of suppressed spreading of TRCs that may enable us to distinguish TRC population from a pool of heterogeneous tumor cell population.

KEYWORDS:

Cell adhesion and spreading; Focal adhesions; Tension gauge tethers; Tumor repopulating cells; smFISH

PMID:
29673588
PMCID:
PMC6133653
DOI:
10.1016/j.bbrc.2018.04.085
[Indexed for MEDLINE]
Free PMC Article

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