Adoptive Immunotherapy for Epithelial Ovarian Cancer Using T-cells Simultaneously Targeted to Tumor and Tumor-Associated Macrophages.

摘要

Our initial hypothesis was that chimeric antigen receptor (CAR)- based immunotherapy of epithelial ovarian carcinoma (EOC) could be potentiated by depletion of tumor-associated macrophages (TAM). To test this, we engineered T-cells to express CARs with specificity for MUC1 (expressed by tumor cells) and CSF-1R (expressed both by tumor cells and TAM). In-vitro experiments demonstrated some efficacy of this approach but significant anti-tumor activity could not be confirmed in-vivo. Consequently, a revised statement of work was agreed in which CAR-mediated targeting of ErbB receptors by EOC tumor cells was pursued instead. A CAR termed T1E28z was engineered which engages several ErbB receptor dimers that are upregulated in EOC. Liposomal clodronate was used to achieve depletion of TAM. T1E28z-transduced T-cells proved effective in killing both autologus patient-derived tumor cell cultures and EOC cell lines (IGROV-1 and SKOV-3) in-vitro. Using bioluminescence imaging (BLI), we then demonstrated that T1E28z+ T-cells mediated the regression of established intraperitoneal SKOV-luc tumors in SCID Beige mice. Highly efficient depletion of TAM was achieved using liposomal clodronate. However, this did not influence anti-tumor activity and appeared to reduced efficacy somewhat. To monitor Tcell persistence in this model, renilla luciferase was co-expressed in T1E28z+ T- cells. This analysis revealed that T-cells undergo progressive decline in tumor- bearing mice, providing a rationale for repeated T-cell administration. In support of this, we found that dual dosing with T1E28z+ T-cells enhanced therapeutic efficacy in this model. Bridging the gap to clinical implementation, proof of concept was also demonstrated for the use of the human sodium iodide symporter (hNIS) as a clinically applicable imaging reporter of T-cell location. We provide evidence that administration of 99mTc-pertechnetate enables the serial real-time tracking of T1E28z/hNIS+ T-cells in-vivo, using SPECT-CT.