Abstract 3605: Combined inhibition of IL-1, CXCR1/2, and TGFβ signaling pathways modulates in vivo acquired resistance to anti-VEGF treatment

Abstract

Abstract Introduction: Resistance of tumors to antiangiogenic therapies is becoming increasingly relevant. We recently identified interleukin (IL)-1, CXC receptors (CXCR)1/2 ligands, and Transforming Growth Factor β (TGFβ) among the proinflammatory factors that were expressed at higher levels in murine models resistant to the anti-VEGF antibody bevacizumab. Here, we hypothesized that the combined inhibition of these proinflammatory signaling pathways might reverse the resistance to anti-VEGF treatment. Methods: Bevacizumab-resistant FGBR orthotopic tumor bearing mice received bevacizumab alone or in combination with a recombinant human IL-1 receptor antagonist, a monoclonal antibody against TGFβ Receptor type II, and a recombinant antibody binding CXCR1/2 ligands. Western blot analysis was performed to assess the activity of p65 NFB, Smad2 and on the expression of IL-6 in FGBR cells in culture. Immunohistochemical analysis of FFPE sections from FGBR tumors was performed to assess Smad2 phosphorylation and IL-6 expression. Wound healing assay was performed to assess cell motility in FGBR cells in culture. Immunohistochemical analysis was performed to assess the expression of E-Cadherin and Vimentin in FGBR tumors. Immunohistochemical analysis was performed to estimate the presence of Cd11b+ cells. Results: The combination of these agents with bevacizumab reduced the tumor burden and significantly prolonged mice survival if compared with single agent bevacizumab. Tumors from mice receiving the combination treatment demonstrated significantly lower expression of IL-6 and phosphorylation of p65 and Smad2 when compared with control. FGBR cells treated in vitro with the three agents plus bevacizumab had significantly higher levels of E-cadherin and lower levels of Vimentin, and exhibited significantly lower migration rates than did their bevacizumab- treated controls. Consistently, tumors from mice receiving the combination treatment demonstrated significantly higher expression of E-cadherin, lower levels of Vimentin, and a significantly lower infiltration by CD11b+ cells when compared with bevacizumab -treated controls. Conclusion: This study suggests that inhibition of IL-1, CXCR1/2, and TGFβ signaling pathways is a potential therapeutic approach to modulate the acquired resistance to anti-VEGF treatment by reversing EMT and inhibiting CD11b+ proangiogenic myeloid cells tumor infiltration. Citation Format: Carmine Carbone, Anna Tamburrino, Geny Piro, Marco Zanotto, Maria Mihaela Mina, Silvia Zanini, Federico Boschi, Aldo Scarpa, Giampaolo Tortora, Davide Melisi. Combined inhibition of IL-1, CXCR1/2, and TGFβ signaling pathways modulates in vivo acquired resistance to anti-VEGF treatment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3605. doi:10.1158/1538-7445.AM2015-3605