Abstract 1450: Anti-EGF antibodies generated by vaccination significantly improve the activity of kinase inhibitors in preclinical models

Abstract

Abstract Background: We have previously described that EGF blocks the activity of EGFR tyrosine kinase inhibitors (EGFR-TKIs) in EGFR mutant NSCLC cells, an effect that is reversed by anti-EGF antibodies generated by vaccination (anti-EGF VacAbs) (1). In this study we aimed to determine the effect of EGF and anti-EGF Vac Abs in the activity of different kinase inhibitors in tumor cell lines with different genetic alterations. Methods: Anti-EGF VacAbs were obtained by immunizing rabbits with recombinant EGF. The cell lines used in this study were H2228 and H3122 (NSCLC, EML4-ALK positive), H23 (NSCLC, KRAS-G12C), DLD1 (colorectal carcinoma, KRAS-G13D), PC9 and PC9-GR4 (NSCLC, EGFR-mut). Tumor cell lines were treated with EGF, anti-EGF VacAbs and combinations with the kinase inhibitors alectinib, crizotinib, brigatinib (ALK inhibitors), trametinib (MEK inhibitor), dacomitinib and osimertinib (EGFR inhibitors). Cell viability was analyzed by MTT, changes of total and phosphorylated proteins were determined by Western blot and emergence of resistance by direct microscopic examination in low density cultures. Results: EGF significantly decreased the antitumor activity of alectinib, crizotinib and brigatinib in ALK translocated cells (H2228 and H3122), trametinib in KRAS mutant cells (H23 and DLD1) and osimertinib and dacomitinib in EGFR mutant cells (PC9). In combination with these TKIs, the anti-EGF VacAbs reversed the effects of EGF and significantly potentiated the antitumor activity of all the kinase inhibitors, blocking the activation of EGFR, Akt and Erk. Finally, the addition of the anti-EGF VacAbs to the culture medium delayed the appearance of resistant clones to kinase inhibitors. Conclusions: Anti-EGF VacAbs potentiate the antitumor effects of ALK, MEK and EGFR kinase inhibitors in tumor cell lines and delay the emergence of resistance in vitro. A clinical trial is currently testing anti-EGF vaccination in combination with afatinib in EGFR-mut advanced NSCLC patients.(1)Anti-Epidermal Growth Factor Vaccine Antibodies Enhance the Efficacy of Tyrosine Kinase Inhibitors and Delay the Emergence of Resistance in EGFR Mutant Lung Cancer Cells” Codony-Servat J, García-Roman S, Molina-Vila MÁ, et al. J Thorac Oncol. 2018. Citation Format: Jordi Codony-Servat, Silvia Garcia-Roman, Miguel Ángel Molina-Vila, Jordi Bertran-Alamillo, Ana Giménez-Capitán, Santiago Viteri, Andrés F. Cardona, Delvys Rodríguez, Manuel Cobo, Noemi Reguart, Niki Karachaliou, Erik d'Hondt, Rafael Rosell. Anti-EGF antibodies generated by vaccination significantly improve the activity of kinase inhibitors in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1450.