CAR T cells targeting α_vβ₃integrin are effective against advanced cancer in preclinical models

Abstract

Objective: Integrins are heterodimeric receptors that convey cell-to-cell and cell-to-matrix interactions. Integrin αvβ3 is expressed in several tumour entities including melanoma, glioblastoma, breast, pancreatic and prostate cancer, where it promotes tumour cell survival and metastasis. Here, we generated αvβ3-specific chimeric antigen receptor (CAR) T-cells and analysed their antitumour function in pre-clinical models in vitro and in vivo. Methods: αvβ3-CARs comprising a super-humanised hLM609 targeting domain with either high or low affinity (hLM609v7, Kd = 3 nM vs. hLM609v11, Kd = 160 nM) and equipped with either a long or a short IgG4-Fc extracellular spacer (229 vs. 12 amino acids) were expressed in CD8+ and CD4+ T-cells through lentiviral transduction. Results: αvβ3-CAR T-cells eliminated αvβ3-positive tumour cells rapidly and specifically, produced IFN-γ and IL-2 (CD4+ > CD8+) and exhibited productive proliferation. In vitro, we observed the strongest reactivity with the higher-affinity hLM609v7 αvβ3-CAR in the short spacer configuration, consistent with the tumour membrane-distal localization of the hLM609 epitope. In a murine xenograft model of metastatic A-375 melanoma, the strongest antitumour effect was mediated by the lower-affinity hLM609v11 αvβ3-CAR. Notably, a single administration of hLM609v11 αvβ3-CAR T-cells was able to induce complete elimination of melanoma lesions, leading to long-term tumour-free survival. Conclusions: These data establish αvβ3 integrin as a novel target for CAR T-cell immunotherapy, and affirm our previous notion that binding domain affinity and spacer length can be calibrated to augment CAR reactivity. Clinical implications: αvβ3-CAR T-cells have therapeutic potential in several prevalent solid tumours, including melanoma and triple-negative breast cancer.

Halting the vicious cycle within the multiple myeloma ecosystem: blocking JAM-A on bone marrow endothelial cells restores angiogenic homeostasis and suppresses tumor progression

“…32 We found a significant expression of FGF-2, a potent stabilizer and activator of a ternary complex involving JAM-A, CD9 and αvβ3 integrin, a novel potential therapeutic target. 33 Peddibhotla et al described that the aggregation of this ternary complex can activate downstream pathway cascades to induce proliferation, migration and an angiogenic stimulus to endothelial cells. 34 Our in silico validation shed more light on this pathophysiological process.…”

CAR T cells for brain tumors: Lessons learned and road ahead

“…Other lymphocyte models have leverage chemokines to increase tumor accumulation with the introduction of receptors such as CXCR4, CXCR1, CXCR2, CCR7, and CX3CR1 . Additional targeting of endothelial adhesion molecules or vascular cytokines upregulated in brain tumors could also be a worthwhile approach to enhance CAR T cell accumulation at the tumor site . To improve cell localization, chemokine receptor‐engineered T cells should be designed for the chemokine signaling unique to each tumor.…”

“…221 Additional targeting of endothelial adhesion molecules or vascular cytokines upregulated in brain tumors could also be a worthwhile approach to enhance CAR T cell accumulation at the tumor site. 178,222 To improve cell localization, chemokine receptor-engineered T cells should be designed for the chemokine signaling unique to each tumor. Such strategies to improve tumor trafficking are important, as preclinical models suggest that trafficking can often be highly inefficient with only a minor fraction of the adoptively transferred cells infiltrating the tumor.…”

ROR1-CAR T cells are effective against lung and breast cancer in advanced microphysiologic 3D tumor models

“…There is a continuous effort in the field to optimize existing and to develop novel CAR designs. We and others have shown in previous work that, for example, the choice of targeting domain, spacer design, and signaling module affect tumor cell recognition and antitumor function of CAR T cells (5, 11,30). However, there is presently no consensus on whether a single assay or a combination of in vitro and in vivo assays constitutes a "gold standard" for evaluating CARs and for predicting safety and efficacy in humans (18).…”