Macrophage contact induces RhoA GTPase signaling to trigger tumor cell intravasation

M. Roh-Johnson*, J. J. Bravo-Cordero, A. Patsialou, V. P. Sharma, P. Guo, H. Liu, L. Hodgson, J. Condeelis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

146 Scopus citations


Most cancer patients die as a result of metastasis, thus it is important to understand the molecular mechanisms of dissemination, including intra- and extravasation. Although the mechanisms of extravasation have been vastly studied in vitro and in vivo, the process of intravasation is still unclear. Furthermore, how cells in the tumor microenvironment facilitate tumor cell intravasation is still unknown. Using high-resolution imaging, we found that macrophages enhance tumor cell intravasation upon physical contact. Macrophage and tumor cell contact induce RhoA activity in tumor cells, triggering the formation of actin-rich degradative protrusions called invadopodia, enabling tumor cells to degrade and break through matrix barriers during tumor cell transendothelial migration. Interestingly, we show that macrophage-induced invadopodium formation and tumor cell intravasation also occur in patient-derived tumor cells and in vivo models, revealing a conserved mechanism of tumor cell intravasation. Our results illustrate a novel heterotypic cell contact-mediated signaling role for RhoA, as well as yield mechanistic insight into the ability of cells within the tumor microenvironment to facilitate steps of the metastatic cascade.

Original languageEnglish (US)
Pages (from-to)4203-4212
Number of pages10
Issue number33
StatePublished - Aug 14 2014


  • RhoA biosensor
  • cancer
  • heterotypic cell contact
  • invadopodia
  • macrophages
  • tumor cell intravasation

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Cancer Research


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