Defining the role of CNPY2 in promoting tumor progression through mediation of macrophage.

Abstract Liver cancer is one of the most common types of cancer. More than 700,000 people are diagnosed with this cancer each year throughout the world. Liver cancer is responsible for more than 30,000 new cases and 12,000 deaths a year in the United States. Liver cancer has been found to be highly associated with ER stress/unfolded protein response (UPR)-induced chronic inflammation; however, the mechanisms remain unclear. Using a genetic approach, we have found that deletion of an ER protein, CNPY2, from macrophages prevents carcinogen-induced hepatocellular carcinoma, accompanied by reduced ER stress/UPR signals and tumor- associated macrophages in tumors. Furthermore, CNPY2 is required for pro-inflammatory cytokines, IL6 and TNFα released from Kupffer cells/liver macrophages. We also observed that CNPY2 plays a central role in regulating both ER stress/UPR and TLR4 signaling, two pathways known to promote cytokine production and differentiation of macrophages. Together these observations suggested that CNPY2 promotes liver oncogenesis through regulation of macrophages. In this proposal, I will aim to address several fundamental questions in the field of HCC: 1) what is the mechanism by which CNPY2 transcriptionally regulates production of IL6 and IL23 in macrophages. Are both the UPR and TLR4 pathways involved in this regulation? 2) what is the biochemical and structural basis for the roles of CNPY2 in promoting TLR4 signaling-dependent cytokine production in macrophages. Solving crystal structure of CNPY2 will help drug development against CNPY2. 3) The potential mechanism by which CNPY2 regulates differentiation, infiltration and function of tumor-associated macrophages in HCC. 4) What is the role of CNPY2 in tumor immunity? Does targeting CNPY2 improve anti-tumor immunity in HCC? Our traditional and conditional Cnpy2 KO mice are unique models for addressing these questions. Successful execution of this work will significantly advance the field. In the longer term, this study may lay a strong foundation for the development of a new class of therapeutics for cancer, based on the rational design of CNPY2 inhibitors against tumor-associated macrophages.