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MA04 - HER2, P53, KRAS and Other Targets in Advanced NSCLC (ID 380)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Advanced NSCLC
- Presentations: 1
MA04.11 - Mechanistic Insights into CAR T-Cell Efficacy in the Treatment of Heterogenous Antigen Expressing Lung Adenocarcinoma (ID 6039)
16:00 - 17:30 | Author(s): A.J. Bograd
Our laboratory has translated (NCT02414269, NCT02792114) mesothelin (MSLN), a cancer-antigen, targeted chimeric antigen receptor (CAR) T-cell therapy to solid tumors including for lung adenocarcinoma (ADC) patients. The goal of this study is to investigate the anti-tumor efficacy of MSLN CAR T cells against lung ADC with heterogenous MSLN expression, and further develop mechanistic insights to potentiate the therapy.
Human CAR T cells transduced with M28z, MSLN CAR with CD28 costimulation, were tested in vitro (cytotoxicity by Cr release assay, proliferation, cytokine secretion, LFA-1/ICAM-1 [lymphocyte function associated antigen-1/intercellular adhesion molecule 1] adhesion assay, and flow cytometry) and in vivo (tumor and T-cell bioluminescence imaging [BLI], survival) against low-, high- or a mixture (50:50 or 70:30) of MSLN-expressing A549 human lung ADC.
MSLN CAR T cells demonstrate antigen-intensity dependant cytotoxicity against both low- and high- MSLN-expressing A549 cells with additive bystander cytotoxicity against Cr-labelled low-MSLN A549 cells in the mixture both in vitro (Figure Panel A) and in vivo (22 days delay in tumor progression by low-MSLN A549 cells). Flow cytometry demonstrated ICAM-1 overexpression on low-MSLN A549 cells when treated with effector cytokine-rich supernatant collected by exposure of CAR T cells to high-MSLN A549 cells (Panel B), LFA-1 expression by MSLN-activated CAR T cells (Panel B). Activated CAR T cells adherence to ICAM-Fc coated plates compared to controls (Panel C). LFA-1/ICAM-1 expression promoted adherence of antigen-activated CAR T cells to low antigen-expressing tumor cells (Panel D), which is inhibited in the presence of LFA-1 blocking antibody (Panel E). Figure 1
We provide a mechanistic reason for the antigen-specific, bystander efficacy of CAR T cells against low-antigen expressing lung cancer cells. Strategies to augment LFA-ICAM interactions between CAR T cells and cancer cells can effectively translate mesothelin-targeted CAR T-cell therapy against heterogenous antigen-expressing solid tumor, lung cancer.
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