Abstract
Immune checkpoints serve as regulatory pathways that are essential for regulating immune response and homeostasis. As such, many components along the pathway have emerged as pivotal targets in cancer therapy. To overcome the treatment resistance and limited efficacy encountered by current immune checkpoint therapies, there is an urgent need for new immunotherapeutic targets and strategies. V-domain Ig suppressor of T cell activation (VISTA) is an immune checkpoint protein with a unique expression pattern and has emerged as a novel therapeutic target in anti-tumor immunotherapy; however, the precise role of VISTA and its regulatory mechanisms in tumor cells remain incompletely understood. Here, we identify a novel strategy targeting VISTA for cancer immunotherapy, enhancing therapeutic outcomes. Mechanistically, we show that VISTA undergoes anaphase-promoting complex/cyclosome (APC/C)/CDH1-mediated ubiquitination and subsequent proteasomal degradation, a process that can be reversed by the deubiquitinase USP2. Therapeutically, the USP2 inhibitor MS102 significantly reduces VISTA protein abundance in vitro and in vivo, enhances T cell responses, and synergizes with anti-PD-1 immunotherapy to improve survival in syngeneic mouse tumor models. Our findings reveal a regulatory network for VISTA stability control and support the combination of USP2 inhibitors with anti-PD-1 immunotherapy to enhance anti-tumor immune responses.