Funded by the Apple Gold Group
The CALM-AF10 chromosomal abnormality is seen in aggressive pediatric and adult acute leukemias that have a poor prognosis. Our lab has discovered that CALM-AF10 interacts with CRM1, a protein that helps transport other proteins from the nucleus to the cytoplasm. This interaction is required to activate HOXA genes, which play a critical role in both CALM-AF10 and other leukemias. This discovery suggests that CRM1 may be important in other leukemias as well, as is significant because a new class of drugs that inhibit interaction with CRM1 (SINEs-Selective Inhibitors of Nuclear Export) has recently been developed. These drugs are effective in a number of human tumor types, and are currently in clinical trials for adult leukemias. Our studies indicate that SINEs may block cancer cells through an unappreciated and novel mechanism-inhibiting CRM1 involvement in activating HOXA genes. In this proposal, we will examine the molecular mechanisms by which CRM1 activates HOXA genes. We will then identify additional CRM1 target genes that are involved in causing leukemias. Studying this previously unrecognized role for CRM1 will enhance our understanding of how SINEs work, and provide preclinical support for their use in pediatric leukemia clinical trials. Since HOXA genes are involved in many hematopoietic malignancies (including MLL-fusion leukemias that are seen in 80% of infant leukemias), these studies may have broad implications for leukemogenesis.