Development of anti inflammatory agents targeting TonEBP for treatment of chronic inflammatory diseases

Tonicity-responsive enhancer binding protein (TonEBP), also known as nuclear factor of activated T cells 5 (NFAT5), belongs to the Rel family of transcriptional factors which include NF-κB and NFAT. TonEBP is a key regulator in chronic inflammatory diseases such as rheumatoid arthritis, atherosclerosis, diabetic nephropathy and hepatocellular carcinoma. TonEBP is a rate-limiting component of “pro-inflammatory enhanceosome” in which TonEBP provides a physical tether between activated transcription factors NF-κB and AP-1 to p300 and RNA polymerase II. Assembled in response to inflammatory signals, the pro-inflammatory enhanceosome drives the transcription of TNF-α, IL-1β, IL-6, MCP-1, iNOS, and COX-2. We discovered a class of compounds (CXs) targeting TonEBP. CXs blocked the assembly of the pro-inflammatory enhancesome and potently suppressed the inflammation-induced expression of TNF-α, IL-1β, IL-6, MCP-1, iNOS, and COX-2. Orally administered CXs exhibited remarkable therapeutic activities in mouse models of inflammatory arthritis. Using an alkynyl derivative of a CX and click reaction, we found that CX was covalently attached to TonEBP by alkylation but not to other components of the enhanceosome. Cells harboring a site-directed mutant TonEBP molecule whose amino acid residues for the alkylation were removed exhibited a markedly reduced sensitivity to CXs. These data demonstrate that CXs are a new class of anti-inflammatory agents with a novel mode of action. Citation Format: Byeongjin YE, Hyug Moo Kwon, Soo Youn Choi, Jun Ho Lee, Hyun Je Kang, Cheol-Min Park. Development of anti inflammatory agents targeting TonEBP for treatment of chronic inflammatory diseases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1290.