Downregulation of major histocompatibility complex I (MHC-I) on tumor cells is a primary means of immune evasion by many types of cancer. Additionally, MHC-I proteins are a primary target of humoral and cellular mechanisms associated with transplant rejection. Transmissible tumors that overcome allograft rejection mechanisms and evade anti-tumor immunity have killed thousands of wild Tasmanian devils (Sarcophilus harrisii). Interferon-gamma (IFNG) upregulates surface MHC-I expression on devil facial tumor (DFT) cells but is not sufficient to induce tumor regressions. Transcriptome analysis of IFNG-treated DFT cells revealed strong upregulation of NLRC5, a master regulator of MHC-I in humans and mice. To explore the role of NLRC5 in transmissible cancers, we developed DFT cells lines that constitutively overexpress NLRC5. Transcriptomic results suggest that the role of NLRC5 as a master regulator of MHC-I is conserved in devils. Furthermore, NLRC5 was shown to drive the expression of many components of the antigen presentation pathway. To determine if MHC-I is a target of allogeneic immune responses, we tested serum from devils with natural DFT regressions against DFT cells. Antibody binding occurred with cells treated with IFNG and overexpressed NLRC5. However, CRISPR/Cas9-mediated knockout of MHC-I subunit beta-2-microglobulin (B2M) eliminated antibody binding to DFT cells. Consequently, MHC-I could be identified as a target for anti-tumor and allogeneic immunity and provides mechanistic insight into MHC-I expression and antigen presentation in marsupials. NLRC5 could be a promising target for immunotherapy and vaccines to protect devils from transmissible cancers and inform development of transplant and cancer therapies for humans.
Importantly, the techniques are readily transferable for testing gene function in DFT2 cells and other non-traditional species.
Purpose Downregulation of MHC class I (MHC-I) is a common immune evasion strategy of many cancers. Similarly, two allogeneic clonal transmissible cancers have killed thousands of wild Tasmanian devils (Sarcophilus harrisii) and also modulate MHC-I expression to evade anti-cancer and allograft responses. IFNG treatment restores MHC-I expression on devil facial tumor (DFT) cells but is insufficient to control tumor growth. Transcriptional co-activator NLRC5 is a master regulator of MHC-I in humans and mice but its role in transmissible cancers remains unknown. In this study, we explored the regulation and role of MHC-I in these unique genetically mis-matched tumors. Methods We used transcriptome and flow cytometric analyses to determine how MHC-I shapes allogeneic and anti-tumor responses. Cell lines that overexpress NLRC5 to drive antigen presentation, and B2M-knockout cell lines incapable of presenting antigen on MHC-I were used to probe the role of MHC-I in rare cases of tumor regressions. Results Transcriptomic results suggest that NLRC5 plays a major role in MHC-I regulation in devils. NLRC5 was shown to drive the expression of many components of the antigen presentation pathway but did not upregulate PDL1. Serum from devils with tumor regressions showed strong binding to IFNG-treated and NLRC5 cell lines; antibody binding to IFNGtreated and NRLC5 transgenic tumor cells was diminished or absent following B2M knockout. Conclusion MHC-I could be identified as a target for anti-tumor and allogeneic immunity. Consequently, NLRC5 could be a promising target for immunotherapy and vaccines to protect devils from transmissible cancers and inform development of transplant and cancer therapies for humans.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.