Parthanatos-inducing zinc agent C010DS-Zn elicits anti-tumor immune responses involving T cells and macrophages in vivo

Chung, Jinhyuk Fred; Her, Zhisheng; Kong, Wai Mun; Chen, Qingfeng

Immune checkpoint inhibitors opened a new horizon in cancer therapy by enabling durable and complete responses in patients, but their wider application against general solid cancers has been hampered by the lack of a broadly acting anti-cancer immune response initiating agents. Parthanatos is a previously unexplored immunogenic programmed necrosis mechanism that is triggered by the hyperactivation of PARP DNA repair and executed by an efficient DNA-fragmentation mechanism. We developed a proprietary macromolecular zinc complex agent C010DS-Zn that efficiently induced parthanatos against 4T1 murine cancer cells in vitro, which was characterized as PARP-mediated necrotic death with massive DNA damages. Ex vivo screening of its cytotoxicity against a panel of 53 low-passage human solid cancer PDX tumor fragments demonstrated its consistent delivery of characteristically DNA-damaging cell death that was unseen in the corresponding apoptosis positive controls. Further characterization of its in vivo treatment effects versus the immunosuppressive 4T1-Balb/c and immunogenic CT26-Balb/c syngeneic cancer models showed that sufficiently high intravenous C010DS-Zn treatments led to robust initiation of the tumor-suppressed antitumor immune compartments such as T cells and macrophages. At lower non-anticancer doses, C010DS-Zn treatment still led to significantly reduced macrophage content and inflammation in the 4T1 tumor, suggesting its potential utility against macrophage-mediated inflammations such as those seen in MIS-C or COVID19. Given the observation of its low serum bioavailability in a rat pharmacokinetic study, these results suggest potential development opportunities for C010DS-Zn to become a widely applicable immune initiation agent with chemo-like broad applicability upon its pharmacokinetic improvements.