Specific inhibition of PI3K p110δ inhibits CSF-1-induced macrophage spreading and invasive capacity

Kellie A. Mouchemore, Natalia G. Sampaio, Michael W. Murrey, E. Richard Stanley, Brian J. Lannutti, Fiona J. Pixley

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Colony stimulating factor-1 (CSF-1) stimulates mononuclear phagocytic cell survival, growth and differentiation into macrophages through activation and autophosphorylation of the CSF-1 receptor (CSF-1R). We have previously demonstrated that CSF-1-induced phosphorylation of Y721 (pY721) in the receptor kinase insert triggers its association with the p85 regulatory subunit of phosphoinositide 3′-kinase (PI3K). Binding of p85 PI3K to the CSF-1R pY721 motif activates the associated p110 PI3K catalytic subunit and stimulates spreading and motility in macrophages and enhancement of tumor cell invasion. Here we show that pY721-based signaling is necessary for CSF-1-stimulated PtdIns(3,4,5)P production. While primary bone marrow-derived macrophages and the immortalized bone marrow-derived macrophage cell line M-/-.WT express all three class IA PI3K isoforms, p110δ predominates in the cell line. Treatment with p110δ-specific inhibitors demonstrates that the hematopoietically enriched isoform, p110δ, mediates CSF-1-regulated spreading and invasion in macrophages. Thus GS-1101, a potent and selective p110δ inhibitor, may have therapeutic potential by targeting the infiltrative capacity of tumor-associated macrophages that is critical for their enhancement of tumor invasion and metastasis. CSF-1-induced phosphorylation of CSF-1R Y721 mediates association of PI3K to trigger PIP3 production and spreading and invasive capacity in macrophages. These activities are mediated solely by the p110™ isoform in a macrophage cell line, M-/-.WT, and in primary macrophages. GS-1101, a potent and selective p110™ inhibitor, inhibits macrophage invasion and matrix degradation.

Original languageEnglish (US)
Pages (from-to)5228-5236
Number of pages9
JournalFEBS Journal
Issue number21
StatePublished - Nov 2013


  • CSF-1R
  • GS-1101
  • PI3K p110δ
  • invasion: macrophage

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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