Discovery of OR1011 NFAT Inhibitor as novel Anti-Leukemic Agent

• Angelina Sora, Medical Diagnostics, University of Delaware

• Christian Fernandez, Pharmacology, University of Pittsburgh

Acute Lymphoblastic Leukemia (ALL) is a bone marrow cancer characterized by increased immature B or T cell lymphocytes in the bloodstream. This type of cancer is most common in children and progresses quickly. Targeted therapies for high-risk ALL subtypes are limited. Our study explores the potential of Nuclear Factor of Activated T cells (NFATs) in inhibiting ALL proliferation, offering a new strategy for targeted therapy in ALL. Current pharmacological approaches for inhibiting NFAT activation are drugs such as Cyclosporin A (CsA) and FK506. CsA is a common drug used to prevent organ rejection during transplantations. These FDA-approved medications inhibit NFAT translocation into the nucleus by blocking calcium binding to calcineurin and blocking calcineurin binding to NFAT, respectively. The mechanism of NFAT inhibition used by these drugs prevents activation of all NFATs and calcineurin-activated genes pathways inducing adverse side effects and various sites of toxicity. Our research has focused on the development of a novel small molecule NFAT inhibitor that targets the transcriptional activity of NFAT after its translocation into the nucleus. The experimentation method consisted of identifying this specific NFAT inhibitor, OR1011. Once identified, the study focused on OR1011 inhibition of nuclear NFAT after translocation into the nucleus in contrast to the mechanism utilized by CsA. Western Blot analysis then confirmed the dysregulation of NFAT in ALL, and further experimentation demonstrated the inhibition of NFAT by both cyclosporin A and OR1011 in ALL cell lines. Finally, electrophoretic mobility shift assays illustrated NFAT binding to target DNA sequences and the dose-dependent inhibition of the formation of this complex when treated with OR1011.