Poster Sessions

CANCER-23

Lea Cunningham

L. Cunningham, W. Zheng, N. Southall, J. Marugan, C. Austin, P. Liu

Identifying Novel Inhibitors of Protein-Protein (CBF-beta and RUNX1) Interaction Using an ALPHA Screen-based High-throughput Screening Assay

Core Binding Factor (CBF) abnormalities are associated with approximately 20% of all acute myeloid leukemia (AML), of which approximately half are further sub-classified as acute myelomonocytic leukemia with eosinophilia, also known as AML subtype M4-Eo. Although CBF leukemias carry a relatively favorable prognosis compared to other leukemias, the toxicity of current therapy is associated with significant morbidity and mortality. Rationally-designed targeted therapy such as imatinib for chronic myeloid leukemia (CML) provides both great efficacy and tolerability compared to conventional chemotherapeutic drugs. The fusion gene CBFb-MYH11 is generated by a chromosome 16 inversion that is present in almost all cases of AML subtype M4-Eo. Previous results from in vitro and in vivo studies have shown that CBFb-MYH11 is a key player in the pathogenesis of inversion 16 leukemia and that the encoded fusion protein, CBFb-SMMHC, binds to RUNX1 with high affinity and dominantly inhibits normal RUNX1 function in hematopoiesis. Thus, small molecule inhibitors of the interaction between CBFb and RUNX1 may have potential therapeutic applications for both inversion 16 leukemia as well as other types of leukemia with aberrant RUNX1 function. We developed a CBFb and RUNX1 bead-based proximity assay in Amplified Luminescence Proximity Homogenous Assay (ALPHA) Screen format and optimized it for high throughput screening. This is the first reported use of this technology for a protein-protein interaction screen. A total of 243,398 compounds at 7 different concentrations each were screened with this assay to identify 137 putative inhibitors by Structure-Activity Relationships, and Curve Class. Confirmatory assays are underway.