RhoB is regulated by hypoxia and modulates metastasis in breast cancer

Julia A. Ju, Inês Godet, Josh W. DiGiacomo, Daniele M. Gilkes

Research output: Contribution to journalArticlepeer-review

Abstract

Background: RhoB is a Rho family GTPase that is highly homologous to RhoA and RhoC. RhoA and RhoC have been shown to promote tumor progression in many cancer types; however, a distinct role for RhoB in cancer has not been delineated. Additionally, several well-characterized studies have shown that small GTPases such as RhoA, Rac1, and Cdc42 are induced in vitro under hypoxia, but whether and how hypoxia regulates RhoB in breast cancer remains elusive. Aims: To determine whether and how hypoxia regulates RhoB expression and to understand the role of RhoB in breast cancer metastasis. Methods: We investigated the effects of hypoxia on the expression and activation of RhoB using real-time quantitative polymerase chain reaction and western blotting. We also examined the significance of both decreased and increased RhoB expression in breast cancer using CRISPR depletion of RhoB or a vector overexpressing RhoB in 3D in vitro migration models and in an in vivo mouse model. Results: We found that hypoxia significantly upregulated RhoB mRNA and protein expression resulting in increased levels of activated RhoB. Both loss of RhoB and gain of RhoB expression led to reduced migration in a 3D collagen matrix and invasion within a multicellular 3D spheroid. We showed that neither the reduction nor overexpression of RhoB affected tumor growth in vivo. While the loss of RhoB had no effect on metastasis, RhoB overexpression led to decreased metastasis to the lungs, liver, and lymph nodes of mice. Conclusion: Our results suggest that RhoB may have an important role in suppressing breast cancer metastasis.

Original languageEnglish (US)
Article numbere1164
JournalCancer Reports
Volume3
Issue number1
DOIs
StatePublished - Feb 1 2020

Keywords

  • Rho GTPase
  • RhoB
  • breast cancer
  • cancer metastasis
  • hypoxia

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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