MD, PhD, University of Toronto, Medical Biophysics
Molecular and Cellular Studies of Human Leukemia
The goal of the laboratory is to study the processes involved in the development and progression of human leukemia using the methods of cellular and molecular biology. These studies can be divided into two broad categories. One area involves the identification of genes involved in chromosome translocations. In T cell leukemias/lymphomas the a and d chains of the T cell antigen receptor are frequently involved in chromosome translocations. We have isolated breakpoints on chromosome 11p13 and 10q24 and are currently studying the genes from chromosome 11 and 10 involved in these translocations. As well we have identified other translocations involving this region and are isolating those breakpoints.
The other area involves the growth and regulation of acute myeloblastic leukemia (AML) cells. In culture and likely in vivo the growth of leukemic cells is regulated by agents that interact with cell surface receptors or hormone receptors. The Kit protein which is expressed on early hematopoietic progenitor cells is the receptor for a membrane bound growth factor expressed by bone marrow stromal cells. We have found that Kit is expressed by the leukemic cells of most patients with AML. We are currently investigating the role of this protein in the growth of human leukemic cells.
Hormones such as retinoic acid can induce differentiation and inhibit the growth of AML cells. The effect of these agents is mediated by specific receptors that act within the nucleus of the cell to alter transcription. We are currently trying to identify those genes that are positively or negatively regulated by retinoic acid and determine whether those genes are important for the continued proliferation of the AML cells. Through an increased understanding of the genes involved in the growth of leukemic cells and the agents that can affect their expression we hope to be able to develop strategies that will permit us to regulate the leukemic cell in vivo.
- Champagne, E., Takihara, Y, Sagman, U., de Sousa, J., Burrow, S., Lewis, W.H., Mak, T.W., Minden, M.D. 1989. The T-cell receptor delta chain locus is disrupted in the T-ALL associated t(11;14)(p13;q11) translocation. Blood 73 :1672-7676.
- Wang, C., Koistenen, P., Yang, G.S., Williams, D.E., Lyman, S.D., Minden, M.D., McCulloch, E.A. 1991. Mast cell growth factor, a ligand for the receptor encoded by c-Kit, affects the growth in culture of the blast cells of acute myeloblastic leukemia. Leukemia 5 :493-499.
- Tohda, S., Minden, M.D., McCulloch, E.A. 1991. Interactions between retinoic acid and colony stimulating factors affecting the blast cells of acute myeloblastic leukemia. Leukemia 5 :951-957.
- Tohda, S., Curtis, J.E., McCulloch, E.A., Minden, M.D. 1992. A comparison of the effects of all trans and cis retinoic acid on the blast stem cells of acute myeloblastic leukemia in culture. Leukemia 6 :656.