Macrophages Enhance Migration in Inflammatory Breast Cancer Cells via RhoC GTPase Signaling

Sci Rep. 2016 Dec 19:6:39190. doi: 10.1038/srep39190.

Abstract

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have lymph node involvement and one-third of patients already have distant metastasis at diagnosis. This propensity for metastasis is a hallmark of IBC distinguishing it from less lethal non-inflammatory breast cancers (nIBC). Genetic profiling studies have been conducted to differentiate IBC from nIBC, but no IBC cancer-cell-specific gene signature has been identified. We hypothesized that a tumor-extrinsic factor, notably tumor-associated macrophages, promotes and contributes to IBC's extreme metastatic phenotype. To this end, we studied the effect of macrophage-conditioned media (MCM) on IBC. We show that two IBC cell lines are hyper-responsive to MCM as compared to normal-like breast and aggressive nIBC cell lines. We further interrogated IBC's hyper-responsiveness to MCM using a microfluidic migration device, which permits individual cell migration path tracing. We found the MCM "primes" the IBC cells' cellular machinery to become extremely migratory in response to a chemoattractant. We determined that interleukins -6, -8, and -10 within the MCM are sufficient to stimulate this enhanced IBC migration effect, and that the known metastatic oncogene, RhoC GTPase, is necessary for the enhanced migration response.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cell Differentiation / drug effects
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Chemotactic Factors / pharmacology
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics
  • Culture Media, Conditioned / metabolism
  • Culture Media, Conditioned / pharmacology
  • Female
  • Humans
  • Inflammatory Breast Neoplasms / genetics
  • Inflammatory Breast Neoplasms / metabolism
  • Inflammatory Breast Neoplasms / pathology*
  • Interleukin-10 / analysis
  • Interleukin-10 / metabolism
  • Interleukin-10 / pharmacology
  • Interleukin-6 / analysis
  • Interleukin-6 / metabolism
  • Interleukin-6 / pharmacology
  • Interleukin-8 / analysis
  • Interleukin-8 / metabolism
  • Interleukin-8 / pharmacology
  • Macrophages / cytology
  • Macrophages / metabolism*
  • Microfluidics
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphorylation / drug effects
  • Signal Transduction / drug effects
  • rhoC GTP-Binding Protein / metabolism*

Substances

  • Chemotactic Factors
  • Culture Media, Conditioned
  • Interleukin-6
  • Interleukin-8
  • Interleukin-10
  • Mitogen-Activated Protein Kinases
  • RHOC protein, human
  • rhoC GTP-Binding Protein