Investigator
Academia Sinica
Engineering CAR T cells to secrete VEGF-neutralizing scFvs enhances antitumor activity against solid tumors
Chimeric antigen receptor (CAR) T cell therapy has shown limited efficacy against solid tumors, which often reside in highly immunosuppressive tumor microenvironments (TMEs). TMEs can be highly abundant in vascular endothelial growth factor A (VEGF), which contributes to immunosuppression and abnormal tumor vasculature. Here, we found that CAR T cells engineered to secrete an anti-VEGF single-chain variable fragment (CAR-αVEGF T cells) achieved superior antitumor efficacy against multiple in vivo models of ovarian cancer and glioma, outperforming conventional CAR T cells with and without combination anti-VEGF antibody therapy. Microscopy, flow cytometry, and transcriptomic analyses revealed that armoring the CAR T cells with anti-VEGF single-chain variable fragments enhanced their activation and mitochondrial fitness and enriched immune-stimulatory signatures among endogenous immune cells in the tumor-bearing brain. Moreover, CAR-αVEGF T cells circumvented multiple detrimental effects associated with on-target CAR T cell therapy, including infiltration of suppressive myeloid cells, exaggerated vasculature abnormalities, and hypoxia. Together, our results provide rationale for the clinical translation of CAR-αVEGF T cells as a safe and potent therapy for solid tumors characterized by elevated VEGF.
Novel monoclonal antibody against integrin α3 shows therapeutic potential for ovarian cancer
AbstractOvarian cancer has a high recurrence rate after platinum‐based chemotherapy. To improve the treatment of ovarian cancer and identify ovarian cancer‐specific antibodies, we immunized mice with the human ovarian carcinoma cell line, SKOV‐3, and generated hybridoma clones. Several rounds of screening yielded 30 monoclonal antibodies (mAbs) with no cross‐reactivity to normal cells. Among these mAbs, OV‐Ab 30‐7 was found to target integrin α3 and upregulate p53 and p21, while stimulating the apoptosis of cancer cells. We further found that binding of integrin α3 by OV‐Ab 30‐7 impaired laminin‐induced focal adhesion kinase phosphorylation. The mAb alone or in combination with carboplatin and paclitaxel inhibited tumor progression and prolonged survival of tumor‐bearing mice. Moreover, immunohistochemical staining of ovarian patient specimens revealed higher levels of integrin α3 in cancer cells compared with normal cells. By querying online clinical databases, we found that elevated ITGA3 expression in ovarian cancer is associated with poor prognosis. Taken together, our data suggest that the novel mAb, OV‐Ab 30‐7, may be considered as a potential therapeutic for ovarian cancer.
