Recurrent chromosomal lesions are associated with specific types acute myeloid leukemia (AML), and create fusion genes that induce leukemia. The core-binding factor CBF is a transcription factor that regulates hematopoietic differentiation, and is a frequent target of mutations in acute myeloid leukemia, including the chromosome 16-inversion inv(16) (p13q22). The inversion creates the fusion protein CBF2-SMMHC, which induces leukemia in cooperation with other mutations. The treatment of inv(16) AML has a 5-year overall survival of approximately 50%, highlighting the necessity of developing new therapies. In addition to this inversion, AML cases also present mutations in the CBF factor RUNX1, suggesting that inhibiting CBF function may also be leukemogenic. The goal of this application is to identify small molecules that inhibit function of CBF2-SMMHC without affecting CBF function. To this end, in this application we propose to (1) optimize the assay to 384-well plate format and perform a pilot high throughput screen to identify compounds that inhibit CBF2-SMMHC function, and (2) determine the role of compounds in AML and hematopoietic progenitor cells expressing the fusion protein. Such inhibitors are lacking and are needed as a tool in basic research for the understanding of the molecular pathways downstream of CBF2-SMMHC, and as part of effective targeted therapeutic drugs that force leukemia stem cells to differentiate and die with no effect to normal hematopoietic stem cells. PUBLIC HEALTH RELEVANCE: Current treatments for leukemia patients use chemotherapeutic drugs that affect normal and leukemic cells, frequently causing immune problems and even death. Recent efforts are focusing on developing drugs that specifically affect leukemic cells, but such targeted drug is lacking for acute myeloid leukemia cases expressing the leukemia protein CBF2-SMMHC. In this application we propose to develop inhibitors for the leukemia protein CBF2-SMMHC that will induce differentiation and death of leukemic cells with negligent effect in normal cells. These drugs will be of critical importance as a tool in basic research as well as in the clinic.