Dual targeting of CD155 augments the antitumor efficacy of ROR1-CAR-T cells in ovarian cancer.

BACKGROUND: Exploring novel therapeutic targets and developing targeted therapies constitute an urgent clinical need for improving the prognosis of ovarian cancer (OC), particularly among patients with advanced stages. Currently, chimeric antigen receptor T (CAR-T) cell therapy has been demonstrated to have a remarkable therapeutic effect in hematological malignancies, while its application remains limited in OC due to the absence of appropriate target molecules and the complex immunosuppressive tumor microenvironment (TME). Poliovirus receptor (PVR, CD155) has been the subject of extensive research in the field of regulatory molecules within the immune microenvironment. However, there has been a paucity of research investigating its role in OC. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is barely expressed in normal tissues but widely expressed in tumor tissues, making it a promising target for CAR-T therapy. Nevertheless, the potential effectiveness of CAR-T cell targeting ROR1 in OC remains unknown. Therefore, the purpose of this study is twofold: The primary objective of this study is to investigate the potential efficacy of single-target ROR1-CAR-T cells on OC. The secondary objective is to examine the feasibility of CD155 as an immunotherapy target for OC and to determine whether combined targeting of CD155 can enhance the function of ROR1-CAR-T cells in OC. METHOD: ROR1 and CD155 expression were detected via flow cytometry analysis. In vitro experiments were conducted to explore the regulatory effect of CD155 on OC proliferation, invasion, angiogenesis, and T cell function. ROR1-CAR, CD155-CAR, and ROR1/CD155 bispecific CAR constructs were designed and synthesized. Then, they were introduced into T cells using lentiviral particles to generate CAR-T cells. We subsequently validated the synergistic effects of CD155 in ROR1/CD155 bispecific CAR-T cells based on cytotoxic efficacy, activation, exhaustion, and differentiation status. RESULTS: ROR1-CAR-T cells exhibited tumoricidal activity in OC, but elevated tonic signaling was observed, resulting in rapid depletion. CD155 constitutes an ideal therapeutic target in OC: firstly, ubiquitous CD155 expression in OC cell lines. Secondly, CD155 promotes tumor proliferation, migration, and angiogenesis in OC cell lines, acting as an oncogenic driver. Thirdly, CD155 impairs T cell function and accelerates their depletion, contributing to an immunosuppressive TME. The bispecific CAR-T combined targeting CD155 and ROR1 demonstrated superior cytotoxicity compared to single-target ROR1-CAR-T or CD155-CAR-T. Co-targeting CD155 significantly attenuated tonic signaling and delayed CAR-T cell exhaustion. CONCLUSION: CD155 emerges as a promising therapeutic target for CAR-T therapy in OC. The bispecific CAR-T construct that co-targets CD155 and ROR1 demonstrates superior and durable tumoricidal activity, offering new perspectives on OC targeted therapy.