Limited role for transforming growth factor-β pathway activation-mediated escape from VEGF inhibition in murine glioma models.
The vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β pathways regulate key biological features of glioblastoma. Here we explore whether the TGF-β pathway, which promotes angiogenesis, invasiveness, and immunosuppression, acts as an escape pathway from VEGF inhibition.



The role of the TGF-β pathway in escape from VEGF inhibition was assessed in vitro and in vivo and by gene expression profiling in syngeneic mouse glioma models.



We found that TGF-β is an upstream regulator of VEGF, whereas VEGF pathway activity does not alter the TGF-β pathway in vitro. In vivo, single-agent activity was observed for the VEGF antibody B20-4.1.1 in 3 and for the TGF-β receptor 1 antagonist LY2157299 in 2 of 4 models. Reduction of tumor volume and blood vessel density, but not induction of hypoxia, correlated with benefit from B20-4.1.1. Reduction of phosphorylated (p)SMAD2 by LY2157299 was seen in all models but did not predict survival. Resistance to B20 was associated with anti-angiogenesis escape pathway gene expression, whereas resistance to LY2157299 was associated with different immune response gene signatures in SMA-497 and GL-261 on transcriptomic profiling. The combination of B20 with LY2157299 was ineffective in SMA-497 but provided prolongation of survival in GL-261, associated with early suppression of pSMAD2 in tumor and host immune cells, prolonged suppression of angiogenesis, and delayed accumulation of tumor infiltrating microglia/macrophages.



Our study highlights the biological heterogeneity of murine glioma models and illustrates that cotargeting of the VEGF and TGF-β pathways might lead to improved tumor control only in subsets of glioblastoma.
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Davide
D
Mangani
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Michael
M
Weller
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Emad
E
Seyed Sadr
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Edith
E
Willscher
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Katharina
K
Seystahl
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Guido
G
Reifenberger
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Ghazaleh
G
Tabatabai
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Hans
H
Binder
Laboratory of Molecular Neuro-Oncology, Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland (D.M., M.W., E.S.S., K.S., G.T., H.S.); Center for Neuroscience, University of Zurich, Zurich, Switzerland (M.W., G.T.); Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany (E.W., H.B.); Institute of Neuropathology, Heinrich Heine University, Düsseldorf, Germany (G.R.); German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Heidelberg, partner site, Essen/Düsseldorf, Germany (G.R.).
Hannah
H
Schneider
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000818:Animals; D000068258:Bevacizumab / Q000008:administration & dosage; D001932:Brain Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D005910:Glioma / Q000378:metabolism*; D008233:Lymphotoxin-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011720:Pyrazoles / Q000008:administration & dosage; D011804:Quinolines / Q000008:administration & dosage; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D020533:Angiogenesis Inhibitors; D008233:Lymphotoxin-alpha; D011720:Pyrazoles; D011804:Quinolines; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D000068258:Bevacizumab; C557799:LY-2157299
TGF-β; VEGF; coinhibition; escape mechanism; glioblastoma