Investigating anti-Glypican 2 (GPC2) chimeric antigen receptor (CAR) T-cell trafficking and tumor microenvironment (TME) interaction in fully immunocompetent small cell lung cancer (SCLC) mouse models

点击翻译按钮获取中文摘要

SCLC is a highly lethal malignancy. It accounts for approximately 35,000 new cancer cases per year in the United States and 5-year overall survival rates are less than 7%. Still, first-line treatment of SCLC has not changed over the past decades and still relies on platinum-based chemotherapeutic regimens and radiation therapy1. Nevertheless, the extensive efforts that have been made to profoundly characterize SCLC on a genomic and transcriptomic level have lead to identification of relevant oncogenic lesions2. Among them are amplifications of the MYC family genes that can be found in 19% of SCLC3. MYC genes belong to the family of basic helix-loop-helix (bHLH) leucine zipper transcription factors, which are involved in cell cylce progression and proliferation4. So far, direct as well as indirect targeting of MYC familiy members in SCLC has been difficult5. However, in neuroblastoma (NB), where MYCN amplification is frequent, Dr. Crystal Mackall amongst others has identified anti-GPC2 directed antibody-drug conjugates and CAR T-cells to be effective in killing NB cells6,7. Given the recent advances in the field of CAR T-cell therapy including complete and durable responses even in highly aggressive leukemia and lymphoma8–10, I aim at applying anti-GPC2 CAR T-cells for treatment of SCLC.To ensure that GPC2 is a relevant target in SCLC as well, I will analyze GPC2 dependency in the context of MYC/MYCN/MYCL1 amplifications, overexpression and dependency (Aim 1). Notwithstanding, in light of the vastly immunosuppressive TME in SCLC that is capable of creating a functional barrier for CAR T-cells11,12, I will test anti-GPC2 CAR T-cells in genetically engineered mouse models (GEMMs) of SCLC in order to proof efficacy of anti-GPC2 CAR T-cells in fully immunocompetent and autochtonous models of SCLC. SCLC GEMMs will serve as a plattform to further characterize mediators of (un-) succesful anti-GPC2 CAR T-cell trafficking (Aim 2) and interactions of anti-GPC2 CAR T-cells with the immunosuppressive TME in SCLC (Aim 3). In order to succeed with Aim 2 we plan to stain CAR T-cells on tumor tissue of treated mice for identification of (in-)efficient tumor trafficking. For further characterization anti-GPC2 CAR T-cells and tumor endothelial cells will be introduced to CyTOF analysis to identify chemokine receptors and adehsion molecules expressed on their surfaces. Aim 3 will be approached applying single-cell RNA sequencing for identification of cellular components of the TME and their functional state. This multi-pronged approach will help us to derive a detailed understanding of the molecular features and cellular interactions that are necessary for sufficient anti-GPC2 CAR T-cell trafficking and for anti-GPC2 CAR T-cells to successfully conquere the immunosuppressive TME in SCLC. Our work will not only benefit treatment of SCLC, but will guide future CAR T-cell therapy for solid tumors in general.