1. Low-dose carboplatin modifies the tumor microenvironment to augment CAR T cell efficacy in human prostate cancer models
- Author
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Porter, LH, Zhu, JJ, Lister, NL, Harrison, SG, Keerthikumar, S, Goode, DL, Urban, RQ, Byrne, DJ, Azad, A, Vela, I, Hofman, MS, Neeson, PJ, Darcy, PK, Trapani, JA, Taylor, RA, Risbridger, GP, Porter, LH, Zhu, JJ, Lister, NL, Harrison, SG, Keerthikumar, S, Goode, DL, Urban, RQ, Byrne, DJ, Azad, A, Vela, I, Hofman, MS, Neeson, PJ, Darcy, PK, Trapani, JA, Taylor, RA, and Risbridger, GP
- Abstract
Chimeric antigen receptor (CAR) T cells have transformed the treatment landscape for hematological malignancies. However, CAR T cells are less efficient against solid tumors, largely due to poor infiltration resulting from the immunosuppressive nature of the tumor microenvironment (TME). Here, we assessed the efficacy of Lewis Y antigen (LeY)-specific CAR T cells in patient-derived xenograft (PDX) models of prostate cancer. In vitro, LeY CAR T cells directly killed organoids derived from androgen receptor (AR)-positive or AR-null PDXs. In vivo, although LeY CAR T cells alone did not reduce tumor growth, a single prior dose of carboplatin reduced tumor burden. Carboplatin had a pro-inflammatory effect on the TME that facilitated early and durable CAR T cell infiltration, including an altered cancer-associated fibroblast phenotype, enhanced extracellular matrix degradation and re-oriented M1 macrophage differentiation. In a PDX less sensitive to carboplatin, CAR T cell infiltration was dampened; however, a reduction in tumor burden was still observed with increased T cell activation. These findings indicate that carboplatin improves the efficacy of CAR T cell treatment, with the extent of the response dependent on changes induced within the TME.
- Published
- 2023