Abstract 1538: Oncostatin-M ligand-based CAR T-cell therapy targets and eliminates lung adenocarcinoma

Abstract Background: A major barrier to effective CAR T-cell therapy in solid tumors is the dense extracellular matrix and the presence of cancer-associated fibroblasts (CAFs), which together impede CAR T-cell infiltration. To overcome this limitation, our lab has developed an oncostatin-M (OSM) CAR T-cell that targets heterodimers formed between GP130 and either OSMR or LIFR. These heterodimers are expressed on both tumor cells and CAFs, making them attractive therapeutic targets. Here, we evaluate the therapeutic potential of OSM CAR T-cells in lung adenocarcinoma (LAC), a subtype of non-small cell lung cancer that accounts for approximately 40% of all lung cancers. Methods: To measure OSM CAR T-cell killing of CAFs, we co-cultured patient-derived CAFs with untransduced T cells (UT) or OSM CAR T-cells at 1:1 effector-to-target ratios for 48 hours. Interval confocal imaging of co-cultures were performed and cytotoxicity was assessed by quantifying CAF confluence. Next, we used flow cytometry to evaluate the surface expression of GP130, OSMR, and LIFR on four LAC cell lines (PC9, H1975, H2009, H2087) to determine if LAC could be putatively targeted by OSM CAR T-cells. To directly assess OSM CAR T-cell killing of LAC, we performed co-culture assays as described above, with the addition of Incucyte Cytotox dye to assess cytotoxicity by quantifying mean red fluorescence. To further assess the efficacy of OSM CAR T-cell therapy against LAC, we generated luciferase-expressing H1975 cells for subcutaneous implantation into NSG immunodeficient mice. Tumors were monitored until palpable, after which mice were randomized and treated intratumorally with PBS, UTs, or OSM CAR T-cells, with regular monitoring of tumor growth and body weight. Results: Flow cytometry revealed heterogeneous expression of GP130, OSMR, and LIFR across LAC cell lines, with notably higher OSMR expression on H1975 and H2009. OSM CAR T-cells induced robust in vitro cytotoxicity against both LAC cells and patient-derived CAFs, with cytotoxicity correlating positively with OSMR expression levels. In the subcutaneous H1975-luc model, intratumoral administration of OSM CAR T-cells reduced tumor burden without evidence of significant toxicity. Conclusions: These findings support the therapeutic promise of OSM CAR T-cells for targeting LAC. Importantly, depletion of CAFs may enhance CAR T-cell penetration into the tumor microenvironment, addressing a key barrier to efficacy in solid tumors. Future work will be aimed at testing OSM CAR T-cell therapy using an H1975-luc orthotopic model. Citation Format: Kayla Klatt, Daniel Feinberg, Reshmi Parameswaran, . Oncostatin-M ligand-based CAR T-cell therapy targets and eliminates lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1538.