1757 - Development of chimeric antigenic receptor (CAR) against VEGFR2 for solid tumor treatment

Background

Cancer is known to be the second cause of death worldwide. Vascular endothelial growth factors (VEGFs) regulate blood vessel development, the overexpressed of VEGF/VEGFR2 are often associated with angiogenesis, invasion, metastasis and prognosis in cancers. Targeting VEGFR2 by monoclonal antibodies has been associated with a survival benefit across multiple malignancies including lung, gastric and colorectal cancers. In addition to anti-VEGFR2 targeted therapies, immunotherapy including checkpoint blockade, adoptive cell therapy, and chimeric antigen receptor T cell (CART) acts as potential strategies to cure cancer. In this study, we propose VEGFR2-CART as a potential therapeutic strategy for different solid tumors treatment, and its therapeutic efficacy will be further investigated and verified.

Methods

In this study, the anti-VEGFR2 single chain fragment variable (scFv) antibodies were screened by using an automated high throughput phage display system. The binding affinity various CDR sequences to VEGFR2 determined by binding ELISA. We generated CART by transducing human PBMCs with a VEGFR2-CAR 2nd generation lentiviral vector. Cytotoxic ability of the generated CART was assessed by a LDH cytotoxicity assay. To evaluate the biologic effect of VEGFR2-CART cells, a breast xenograft model was performed by injecting HCC1428 cells subcutaneously into the flank of NOD/SCID mice.

Results

Seventy-two VEGFR2 clones with various CDR sequences with the range of binding affinities of 10-8 to 10-10 M were selected. Cell toxicity assays showed that 50∼60% of VEGFR2-overexpressed FS293 cells were killed by VEGFR2-CART cells. To evaluate the biologic effect of VEGFR2-CART cells, a breast xenograft model was performed by injecting HCC1428 cells subcutaneously into the flank of NOD/SCID mice. The results demonstrate that the VEGFR2-CART cells significantly inhibit the growth of HCC1428 due to reduced tumor sizes and weights.

Conclusions

The cytotoxicity assay showed that the VEGFR2-overexpressed FS293 cells were apparently killed by VEGFR2-CART cells. The antitumor effects of the VEGFR2-CART cells have been proved in a murine tumor model, suggesting that targeting VEGFR2 with CART cells can be a novel strategy in cancer immunotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Development Center for Biotechnology.

Funding

The government of the Republic of China (Taiwan).

Disclosure

All authors have declared no conflicts of interest.