The BCR-ABL oncogene is a fusion gene formed by the t(9,22) Philadelphia chromosome found in the chronic and acute phases of chronic myelogenous leukemia. The acute phase is also characterized by additional genetic changes which may be responsible for the transition to acute leukemia. One of these changes is the loss or mutation of the recessive oncogene p53, but the significance of these alterations is unknown. The objective of this research proposal is to determine if alterations in the p53 gene can enhance the transforming potential of the BCR-ABL oncogene in vitro. Patient samples will then be examined for analogous mutations. Unlike the recessive retinoblastoma oncogene, mutations in the p53 gene can act as a dominant negative oncogene. I will study the effect of mutant p53 genes on the growth of fibroblast and hematopoietic cells containing the BCR-ABL gene. Our laboratory has already demonstrated cooperativity between the BCR-ABL and v-myc genes for transformation of rat fibroblast cells. Because of its speed and simplicity I will use this fibroblast model to identify p53 mutations that cooperate with the BCR-ABL gene for transformation. Assays for transformation will include morphology in liquid culture, growth in soft agar, and tumor formation in nude mice. p53 mutations which are transforming in the fibroblast system will be tested for specificity in hematopoietic cells expressing the BCR-ABL gene using mouse bone marrow culture systems already in place in our laboratory. Based on transforming p53 mutations identified in vitro, I will examine blood and bone marrow samples from patients with chronic myelogenous leukemia for analogous p53 mutations. These experiments will use polymerase chain reaction technology to amplify targeted regions of the p53 cDNA from patient samples to study for mutations. The functional significance of any mutation identified in clinical Samples can be tested in the in vitro model. This research will increase our understanding of the acute phase of chronic myelogenous leukemia.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Physician Scientist Award (K11)
Project #
5K11CA001551-03
Application #
3085891
Study Section
Special Emphasis Panel (SRC (B3))
Project Start
1990-07-16
Project End
1995-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
3
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Schools of Arts and Sciences
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
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Afar, D E; Goga, A; Cohen, L et al. (1994) Genetic approaches to defining signaling by the CML-associated tyrosine kinase BCR-ABL. Cold Spring Harb Symp Quant Biol 59:589-94
Afar, D E; Goga, A; McLaughlin, J et al. (1994) Differential complementation of Bcr-Abl point mutants with c-Myc. Science 264:424-6
Sawyers, C L; Gishizky, M L; Quan, S et al. (1992) Propagation of human blastic myeloid leukemias in the SCID mouse. Blood 79:2089-98