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.

The formation of new lymphatic vessels, or lymphangiogenesis, is a critical step of the tissue repair program. In pathological conditions involving chronic inflammation or tumorigenesis, this process is often dysregulated and can contribute to disease progression. Yet, lymphangiogenesis is still incompletely understood. In this study, we identified A2a adenosinergic signaling as an important regulator of inflammatory and tumor-associated lymphangiogenesis. Using Adora2a (A2a)-deficient mice, we demonstrated that A2a signaling was involved in the formation of new lymphatic vessels in the context of peritoneal inflammation. We also demonstrated that tumor-associated and sentinel lymph node lymphangiogenesis were impaired in A2a-deficient mice, protecting them from lymph node metastasis. Notably, A2a signaling in both hematopoietic and non-hematopoietic cells contributed to sentinel lymph node metastasis. In A2a-deficient tumor-draining lymph nodes, impaired lymphangiogenesis was associated with a reduced accumulation of B cells and decreased VEGF-C levels. Supporting a role for non-hematopoietic A2a signaling, we observed that primary murine lymphatic endothelial cells (LEC) predominantly expressed A2a receptor and that A2a signaling blockade altered LEC capillary tube formation in vitro. Finally, we observed that Adora2a, Nt5e and Entpd1 gene expression positively correlated with Lyve1, Pdpn and Vegfc in several human cancers, thereby supporting the notion that adenosine production and A2a receptor activation might promote lymphangiogenesis in human tumors. In conclusion, our study highlights a novel pathway regulating lymphangiogenesis and further supports the use of A2a or adenosine blocking agents to inhibit pathological lymphangiogenesis in cancers and block the dissemination of tumor cells through the lymphatic system.