Advancing Cancer Therapy Predictions with Patient-Derived Organoid Models of Metastatic Breast Cancer

Breast cancer-on-chip for patient-specific efficacy and safety testing of CAR-T cells

Physiologically relevant human models that recapitulate the challenges of solid tumors and the tumor microenvironment (TME) are highly desired in the chimeric antigen receptor (CAR)-T cell field. We developed a breast cancer-on-chip model with an integrated endothelial barrier that enables the transmigration of perfused immune cells, their infiltration into the tumor, and concomitant monitoring of cytokine release during perfused culture over a period of up to 8 days. Here, we exemplified its use for investigating CAR-T cell efficacy and the ability to control the immune reaction with a pharmacological on/off switch. Additionally, we integrated primary breast cancer organoids to study patient-specific CAR-T cell efficacy. The modular architecture of our tumor-on-chip paves the way for studying the role of other cell types in the TME and thus provides the potential for broad application in bench-to-bedside translation as well as acceleration of the preclinical development of CAR-T cell products.

Precision Immunotherapy Utilizing Adapter CAR-T Cells (AdCAR-T) in Metastatic Breast Cancer Leads to Target Specific Lysis

A frequent symptom of metastasized breast cancer (BC) includes the development of malignant pleural effusion (MPE), which contains malignant cells derived from the primary tumor site. The poor prognosis of MPE in metastasized BC indicates the necessity for dependable precision oncology and the importance of models representing the heterogenous nature of metastatic BC. In this study, we cultured MPE-derived metastatic tumor cells from four advanced BC patients using organoid technology. We assessed the expression of tumor-associated antigens on MPE-derived organoid lines by flow cytometry (FC). Based on an individual antigen expression pattern, patient-derived organoids were treated with adapter CAR-T cells (AdCAR-T) and biotinylated monoclonal antibodies targeting CD276, HER2, EGFR, TROP2, or EpCAM. Co-culture assays revealed specific organoid lysis by AdCAR-T depending on individual antigen expression patterns. Our results demonstrate that MPE-derived organoids can serve as a reliable tool for assessing the efficacy of AdCAR-T on metastatic BC in a patient-individualized manner. This approach could potentially be applied in a preclinical setting to instruct therapy decisions. Further, our study demonstrates the feasibility of precision immunotherapy utilizing AdCAR-T to target patient-individualized antigen patterns.