HER2 CAR-T Cells Eradicate Uveal Melanoma and T-cell Therapy–Resistant Human Melanoma in IL2 Transgenic NOD/SCID IL2 Receptor Knockout Mice

Abstract

Chimeric antigen receptors (CAR) can transmit signals akin to those from activated T-cell receptors when bound to a cell surface target. CAR-expressing T cells against CD19 can cause curative effects in leukemia and lymphoma and is approved for clinical use. However, no CART therapy is currently approved for use in solid tumors. We hypothesize that the resistance of solid tumors to CART can be overcome by similar means as those used to reactivate tumor-infiltrating T lymphocytes (TIL), for example, by cytokines or immune checkpoint blockade. Here we demonstrate that CART cells directed against HER2 can kill uveal and cutaneous melanoma cells in vitro and in vivo. Curative effects in vivo were only observed in xenografts grown in a NOD/SCID IL2 receptor gamma (NOG) knockout mouse strain transgenic for human IL2. The effect was target-specific, as CRISPR/Cas9-mediated disruption of HER2 in the melanoma cells abrogated the killing effect of the CART cells. The CART cells were also able to kill melanoma cells from patients resistant to adoptive T-cell transfer (ACT) of autologous TILs. Thus, CART therapy represents an option for patients that do not respond to immunotherapy with ACT of TIL or immune checkpoint blockade. In addition, our data highlight the use of IL2 transgenic NOG mice as models to prove efficacy of CART cell products, possibly even in a personalized manner. Significance: These findings demonstrate that a novel humanized mouse model can help clinical translation of CART cells against uveal and cutaneous melanoma that do not respond to TIL therapy or immune checkpoint blockade.

Engineered IL-7 Receptor Enhances the Therapeutic Effect of AXL-CAR-T Cells on Triple-Negative Breast Cancer

“…To evaluate the activity of AXL-CAR-T cells, the ratio between T cell and the target cell was optimized by cytotoxicity experiments. Based on previous experiments [21] and to visualize the antitumor activity of the enhanced CAR-T cells, effector cell: target cell ratio of 2 : 1, 1 : 1, and 1 : 2, respectively, were tested. After overnight incubation of effector cells and target cells, supernatants were collected from each well and the LDH concentration was measured to evaluate the antitumor activity of CAR-T cells at different ratios with target cells.…”

Supporting clinical decision making in advanced melanoma by preclinical testing in personalized immune-humanized xenograft mouse models

“…Our method could be a valuable early warning that the patient may need additional treatment with, for example, an advanced therapy such as CAR-T cells or a combination therapy. Indeed, we recently demonstrated potent activity of HER2 CAR-T cells in hIL2-NOG but not NOG mice, 17 further positioning the immunehumanized system as a plausible way to devise and test individualized cell therapies.…”

The Role of Checkpoint Inhibitors and Cytokines in Adoptive Cell-Based Cancer Immunotherapy with Genetically Modified T Cells

“…It was found that the second generation CEA specific CAR T secreted IL 2 and IFN γ at a much higher level compared to the first generation CAR T, which ensured their prolonged persistence and marked anticancer effect in the model of metastatic melanoma in vivo [54]. Similar effect was observed for the HER 2 specific CAR T that displayed the anticancer activity in the melanoma model solely in the transgenic mouse strain expressing human IL 2 [55].…”