RAS interaction with PI3K p110α is required for tumor-induced angiogenesis
Miguel Manuel Murillo, … , Gordon Stamp, Julian Downward
Miguel Manuel Murillo, … , Gordon Stamp, Julian Downward
Published July 8, 2014
Citation Information: J Clin Invest. 2014;124(8):3601-3611. https://doi.org/10.1172/JCI74134.
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Research Article Oncology

RAS interaction with PI3K p110α is required for tumor-induced angiogenesis

Abstract

Direct interaction of RAS with the PI3K p110α subunit mediates RAS-driven tumor development: however, it is not clear how p110α/RAS-dependant signaling mediates interactions between tumors and host tissues. Here, using a murine tumor cell transfer model, we demonstrated that disruption of the interaction between RAS and p110α within host tissue reduced tumor growth and tumor-induced angiogenesis, leading to improved survival of tumor-bearing mice, even when this interaction was intact in the transferred tumor. Furthermore, functional interaction of RAS with p110α in host tissue was required for efficient establishment and growth of metastatic tumors. Inhibition of RAS and p110α interaction prevented proper VEGF-A and FGF-2 signaling, which are required for efficient angiogenesis. Additionally, disruption of the RAS and p110α interaction altered the nature of tumor-associated macrophages, inducing expression of markers typical for macrophage populations with reduced tumor-promoting capacity. Together, these results indicate that a functional RAS interaction with PI3K p110α in host tissue is required for the establishment of a growth-permissive environment for the tumor, particularly for tumor-induced angiogenesis. Targeting the interaction of RAS with PI3K has the potential to impair tumor formation by altering the tumor-host relationship, in addition to previously described tumor cell–autonomous effects.

Authors

Miguel Manuel Murillo, Santiago Zelenay, Emma Nye, Esther Castellano, Francois Lassailly, Gordon Stamp, Julian Downward

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Figure 1

Generation of a conditional RBD mutantPik3camouse model.

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Generation of a conditional RBD mutantPik3camouse model. (A) In order ...
(A) In order to assess the degree of recombination of the floxed Pik3ca allele, different tissues from a group of mice were collected no earlier than 21 days after tamoxifen food was withdrawn. DNA extracts were prepared and subjected to PCR analysis for detection of the floxed Pik3ca allele (upper band, 500 bp; lower band, 400 bp). (B–E) Primary MEFs were obtained from tamoxifen-untreated mice containing either the RBD mutant or the WT Pik3ca allele. Cells were treated with vehicle or tamoxifen (1 μM) for 16 hours followed by 24 hours in complete, tamoxifen-free media. Subsequently, cells were starved for 16 hours and treated with EGF (20 ng/ml) (B and C), PDGF (20 ng/ml) (D and E), or vehicle for 10 minutes. Protein extracts were prepared and subjected to Western blot analysis (B and D). Fluorescent secondary antibodies were used, and subsequent quantification in a LI-COR system was performed (C and E). A representative experiment is shown.