Highly proliferative and hypodifferentiated CAR-T cells targeting B7–H3 enhance antitumor activity against ovarian and triple-negative breast cancers

Chimeric antigen receptor (CAR)-T cell immunotherapy is highly effective against hematological neoplasms. However, owing to tumor variability, low antigen specificity, and impermanent viability of CAR-T cells, their use in the treatment of solid tumors is limited. Here, a novel CAR-T cell targeting B7–H3 and incorporating a 4-1BB costimulatory molecule with STAT3-and STAT5-related activation motifs was constructed using lentivirus transduction. B7–H3, a tumor-associated antigen, and its scFv antibody endowed CAR-T cells with tumor-specific targeting capabilities. Moreover, the integration of the trIL2RB and YRHQ motifs stimulated STAT5 and STAT3 in an antigen-dependent manner, inducing a remarkable increase in the proliferation and survival of CAR-T cells via the activation of the JAK-STAT signaling pathway. Besides, the proportion of less-differentiated T cells increased among BB-trIL2RB-z(YRHQ) CAR-T cells. Moreover, BB-trIL2RB-z(YRHQ) effectively inhibited ovarian cancer (OC) and triple-negative breast cancer (TNBC) in vivo at low doses, without high serum levels of inflammatory cytokines and organ toxicity. Therefore, our study proposes a combination of elements for the construction of superior pluripotent CAR-T cells to provide an effective strategy for the treatment of intractable solid tumors. We combined a variety of elements to form a CAR targeting B7–H3. These elements improved the proliferation and stemness of CAR-T cells, and effectively inhibited the growth of ovarian and triple-negative breast cancers. [Display omitted] •Construction of B7–H3-targeted CAR-T cells using a preponderant combination.•The design of CAR enhances the proliferation ability and stemness of CAR-T.•A novel CAR-T targeting B7–H3 exhibits excellent activity in ovarian cancer.•A novel B7–H3-targeted CAR-T inhibits triple negative breast cancer at a low dose.