Abstract 1808: Modulation of the immune cell repertoire and immunogenicity of tumor cells by sorafenib

Abstract Recently, tyrosine kinase inhibitors have been successfully implemented in frontline therapy for the treatment of malignant tumors including renal cell carcinoma (RCC). These different substances provide significant objective clinical responses and a longer progression-free survival of patients. This is mainly caused by the inhibition of cell growth, angiogenesis and induction of apoptosis. In addition, an effect of sorafenib on the frequency and function of T subpopulations, dendritic cells as well as myeloid-suppressor cells has been postulated. The aim of this study was to determine the effect of sorafenib on cell growth, apoptosis and immunogenic properties of RCC cells as well as on the composition of immune subpopulations of peripheral blood mononuclear cells and subsequently immune responses. A direct effect of sorafenib on the expression pattern of a number of immune modulatory components including HLA class I antigens and members of the B7-H family as well as on the proliferation of RCC cell lines was detected. In addition, the frequency and function of different immune cell populations, such as regulatory T cells and myeloid-derived suppressor cells, was altered upon sorafenib treatment. These data suggest a novel activity of sorafenib in tumor patients by extending its activity beyond the tumor endothelium as its major target to the modulation of immune cell function and the immunogenicity of RCC cells. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1808.