ZBP1 is a crucial regulator for tumor necroptosis during tumor development.

Abstract

Abstract Tumor necrosis happens commonly in advanced solid tumors. We reported that necroptosis plays a major role in tumor necrosis. By studying TNF-induced necroptosis, it is now known that receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3) and the mixed lineage kinase domain-like (MLKL) constitute the core of the necroptosis machinery. Two other proteins, Z-DNA-binding protein 1 (ZBP1) and TIR-domain-containing adapter-inducing interferon-β (TRIF) are known to function upstream of RIPK3 and interact with RIPK3 to mediate necroptosis in response to viral infection or TLR signaling respectively. Our study shows that it is the ZBP1, and not RIPK1 nor TRIF, that mediates tumor necroptosis during tumor development in preclinical cancer models. We found that ZBP1 expression is dramatically elevated in the later stages of both the MVT-1 breast cancer model and the MMTV-PyMT, a genetically engineered mouse model (GEMM) of breast cancer, when necrosis happens. Next, we generated CRISPR ZBP1 knockout (ZBP1 KO) MVT-1 cells to examine whether ZBP1 is needed for tumor necroptosis during MVT-1 mammary tumor development. ZBP1 deletion blocks tumor necroptosis during primary tumor development, more importantly, we observed decreased lung metastasis comparing to wildtype. We showed that glucose deprivation (GD) triggers ZBP1-depedent necroptosis in tumor cells. GD causes mitochondrial DNA (mtDNA) release to the cytoplasm and the binding of mtDNA to ZBP1 to activate MLKL in a BCL-2 family protein, NOXA-dependent manner. Therefore, our study reveals ZBP1 as the key regulator of tumor necroptosis and provides a potential drug target for controlling tumor metastasis.