Abstract 5619: Development of a TK1 specific chimeric antigen receptor T-cell for the treatment of non-small-cell lung cancer

Our current research explores the development and tumoricidal activity of chimeric antigen receptor T-cells targeting a new immunotherapeutic target, thymidine kinase 1 (TK1), against non-small lung cancer (NSCLC), both in vitro and in vivo. There has been recent success utilizing CAR T-cell therapy in clinical trials, but it has been mainly focused on the treatment of haematological malignancies targeting CD19. Lung cancer is the most common cause of cancer mortality globally and is responsible for more than one million of deaths every year. Moreover, NSCLC comprises approximately 85 % of all lung cancers. Clinical trials against NSCLC using engineered T-cells targeting NY-ESO-1, VEGFR2, MAGE-A3, and mesothelin are currently ongoing. In spite of efforts to find new molecular targets, CAR T-cell therapy still faces several challenges in the treatment of solid malignancies due to the lack of specific molecular targets. We have previously reported the up-regulation of TK1 in multiple malignant tissues including lung cancer tissues and the presence of TK1 on the cell surface of different NSCLC cell lines, such as H460 and A549. Flow cytometry, scanning electron microscopy and confocal microscopy showed evidence of TK1 on the surface of these cancer cells lines. We have built third generation TK1-CARs with lentiviral and retroviral vectors. The constructions include a single chain variable fragment for TK1, a CD28 and 4-1BB moieties connected with a CD3ζ signaling domain. Confirmation of the CAR expression on transduced human T cells was performed by flow cytometry and confocal microscopy, and approximately 50 % of the transduced T-cells expressed TK1-CARs. Upon co-culturing TK1-CAR T-cells there was a significant increase in T-cell activity and cancer cell lysis elevated as high as 48% in comparison to negative controls. Cytokine profiles revealed a significant increase of the levels of IL-2 and IFN-γ after 24 hrs of co-culturing, indicating T-cell activation. TK1-CAR T-cells, untransduced T-cells, and transduced T-cells with empty vectors were co-cultured with H460 cells and time-lapse videos were recorded, every 5 minutes between 12 and 24 hrs post transduction. Clustering of TK1-CAR T-cells around lung cancer cells and induction of cell death after T-cell synapsis with target cells was observed. Preliminary in vitro data has shown that TK1-CAR T-cells induce specific cell lysis in NSCLC cells. In vivo experiments using xenografts models in SNG mice will be performed. Statistical differences between survival curves of mice treated with TK1 CAR T-cells, untransduced T-cells and transduced T-cells with empty vectors are expected. Note: This abstract was not presented at the meeting. Citation Format: Edwin J. Velazquez, Kiara Vaden, Michelle H. Townsend, Evita G. Weagel, Scott Weber, Richard A. Robison, Kim L. O9Neill. Development of a TK1 specific chimeric antigen receptor T-cell for the treatment of non-small-cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5619. doi:10.1158/1538-7445.AM2017-5619