Lawrence H. Boise, Ph.D.

Professor and Director of Graduate Program, Microbiology and Immunology
Room 3153 Rosenstiel Medical Sciences Building
1600 NW 10th Avenue
Telephone: 305-243-6137
Fax: 305-243-4623
Email:lboise@med.miami.edu

Research Interests:

Regulation of Programmed Cell Death.

Programmed cell death or apoptosis is a process utilized by multicellular organisms to eliminate unnecessary or damaged cells without inducing an inflammatory response. The ability of inducing cellular suicide is required for normal development and maintenance of cell number in multicellular organisms since loss of control of this process can lead to cancer, autoimmune disease or neurodegenerative disorders in mice and humans. The process of cell death is evolutionarily conserved as the hallmarks of apoptosis are found in organisms from the nematode C. elegans to man. Genetic studies in C. elegans have resulted in the cloning and ordering of three genes that either control or execute cell death. Two of these genes ced-3 and ced-4 are required for programmed cell death to occur while a third gene, ced-9 works genetically upstream of ced-3 and ced-4 to block programmed cell death. Homologues of all 3 genes have been found in mammalian cells where ced-3 is a member of the caspase family of cysteine proteases similar to Interluekin 1b-converting enzyme (ICE) and ced-9 is a member of the bcl-2 family. However we have determined that death receptors including CD95 (Fas/APO-1) and TNF RI can activate two death pathways that can be inhibited in cooperative fashion by Bcl-2 and caspase inhibitors. A second interesting outcome of these studies is the finding that two aspects of mitochondrial dysfunction during TNFa-induced apoptosis (release of cytochrome c into the cytoplasm and loss of the inner membrane potential) can be separated. Our results suggest that loss of membrane potential (DYm) is a late event in cell death that occurs after the activation of caspase 9. This would place the mitochondria in two places in the cell death pathway. First the mitochondria are signaling organelles that can initiate death signals through the release of cytochrome c. This can be inhibited by Bcl-2 or Bcl-x L. However once downstream caspases are activated, the mitochondria is a target for inactivation in a Bcl-2-resistant fashion. We are currently determining the mechanism of caspase activated depolarization as well as a potential explanation for the reason mitochondria are inactivated in this fashion.

A second area of investigation in the lab is the induction of apoptosis by novel therapeutic agents for the treatment of multiple myeloma. This incurable neoplasia of the antibody secreting plasma cells is the second most common hematologic malignancy. While many patients initially respond to conventional chemotherapy, they ultimately relapse and the disease becomes refractory to therapy. Therefore new therapies that can function in the face of enhanced resistance are needed. We have found that arsenic trioxide can induce apoptosis in chemorefractory myeloma cell lines as well as in cells isolated from patients in relapse or with refractory disease. Interestingly we have found that ascorbic acid, through the transient lowering of glutathione levels can sensitize myeloma cells to arsenic-induced apoptosis. This has lead to an NCI-sponsored clinical trial to test the safety and efficacy of the combination of arsenic and ascorbic acid for the treatment of refractory/relapsed myeloma. Currently we are investigating the mechanism(s) by which arsenic-induces cell death in these cells as well as initiated investigations into how the biology of a myeloma may result in it sensitivity to targeted agents.

Bortezomib (Velcade^TM) is a proteasome inhibitor that has recently been approved for the treatment of multiple myeloma. We hypothesized that the sensitivity of these cells to proteasome inhibition maybe related to the function of their normal counterparts, plasma cells. These cells are antibody secreting cells that have an extensive endoplasmic reticulum. We have found that inhibition of the proteasome results in endoplasmic reticulum induced stress responses and hypothesize that this is in part the mechanism by which proteasome inhibitors induce apoptosis. We are also currently investigating mechanisms of ER stress and proteasome inhibitor induced apoptosis.

Selected Publications:

Johnson, B.W.*, Cepero, E*., Boise, L.H. Bcl-xL Inhibits Cytochrome c Release but Not Mitochondrial Depolarization during the Activation of Multiple Death Pathways by Tumor Necrosis Factor-a. J. Biol. Chem.275:31546-31553, 2000 . (*co-first author).

Grad, J.M*., Bahlis, N.J*., Reis, I., Oshiro, M.M., Dalton, W.S., Boise, L.H. Ascorbic acid enhances arsenic trioxide-induced cytotoxicity in multiple myeloma cells. Blood. 98, 805-813, 2001 (*co-first author).

Bahlis, N., McCafferty Grad, J., Jordan-McMurry, I., Neil, J., Reis, I., Kharfan-Dabaja, M., Eckman, J., Goodman, M., Fernandez, H.F., Boise, L.H., Lee, K.P. Arsenic trioxide combined with ascorbic acid-mediated depletion of intracellular glutathione: A phase I study in relapsed and refractory multiple myeloma. Clinical Cancer Res. 8, 3658-3668, 2002.

McCafferty Grad, J., Bahlis, N., Aguilar, T., Krett, N., Lee, K.P., Boise, L.H. Arsenic trioxide uses caspase dependent and caspase independent death pathways in multiple myeloma cells. Mol. Cancer Ther, 2, 1155-1164, 2003.

Beaupre, D.M., Cepero, E., Obeng, E.A., Boise, L.H., Lichtenheld, M.G. R115777 induces Ras independent apoptosis in myeloma cells via multiple intrinsic pathways. Mol. Cancer. Ther 3, 179-86, 2004.

Wilkinson, J.C., Cepero, E., Boise, L.H., Duckett, C.S. An upstream regulatory role for XIAP in receptor-mediated apoptosis. Mol. Cell. Biol. 24, 7003-7014, 2004.

Cepero, E. King, A.M., Perez, R.G., Boise, L.H. Caspase-9 and effector caspases have sequential and distinct effects on mitochondria. Oncogene, 24, 6354-6366, 2005.

Obeng, E.A., Boise, L.H. Caspase-12 and Caspase-4 are not required for caspase-dependent endoplasmic reticulum induced apoptosis. J. Biol. Chem. 280, 29578-29587, 2005.

Obeng, E.A., Carlson, L.M., Gutman, D., Harrington, Jr., W.J., Lee, K.P., Boise, L.H. Proteasome inhibitors induce a terminal unfolded protein response in multiple myeloma cells. Blood, 107, 4907-4916, 2006.