Dual inhibition of Ang-2 and VEGF receptors normalizes tumor vasculature and prolongs survival in glioblastoma by altering macrophages

TE Peterson, ND Kirkpatrick, Y Huang… - Proceedings of the …, 2016 - National Acad Sciences
TE Peterson, ND Kirkpatrick, Y Huang, CT Farrar, KA Marijt, J Kloepper, M Datta
Proceedings of the National Academy of Sciences, 2016National Acad Sciences
Glioblastomas (GBMs) rapidly become refractory to anti-VEGF therapies. We previously
demonstrated that ectopic overexpression of angiopoietin-2 (Ang-2) compromises the
benefits of anti-VEGF receptor (VEGFR) treatment in murine GBM models and that
circulating Ang-2 levels in GBM patients rebound after an initial decrease following
cediranib (a pan-VEGFR tyrosine kinase inhibitor) administration. Here we tested whether
dual inhibition of VEGFR/Ang-2 could improve survival in two orthotopic models of GBM …
Glioblastomas (GBMs) rapidly become refractory to anti-VEGF therapies. We previously demonstrated that ectopic overexpression of angiopoietin-2 (Ang-2) compromises the benefits of anti-VEGF receptor (VEGFR) treatment in murine GBM models and that circulating Ang-2 levels in GBM patients rebound after an initial decrease following cediranib (a pan-VEGFR tyrosine kinase inhibitor) administration. Here we tested whether dual inhibition of VEGFR/Ang-2 could improve survival in two orthotopic models of GBM, Gl261 and U87. Dual therapy using cediranib and MEDI3617 (an anti–Ang-2–neutralizing antibody) improved survival over each therapy alone by delaying Gl261 growth and increasing U87 necrosis, effectively reducing viable tumor burden. Consistent with their vascular-modulating function, the dual therapies enhanced morphological normalization of vessels. Dual therapy also led to changes in tumor-associated macrophages (TAMs). Inhibition of TAM recruitment using an anti–colony-stimulating factor-1 antibody compromised the survival benefit of dual therapy. Thus, dual inhibition of VEGFR/Ang-2 prolongs survival in preclinical GBM models by reducing tumor burden, improving normalization, and altering TAMs. This approach may represent a potential therapeutic strategy to overcome the limitations of anti-VEGFR monotherapy in GBM patients by integrating the complementary effects of anti-Ang2 treatment on vessels and immune cells.
National Acad Sciences