The major objectives of our research endeavors are to examine two macrophage functions, cytostasis and cytolysis, that adversely affect tumor cells to determine whether they are independent events caused by macrophages at different stages of activation and/or by different macrophage subpopulations. The experimental approaches will involve both the comparison of cytostatic and cytolytic activities with respect to a variety of parameters known to affect macrophage activities. Activated macrophages can recognize, bind to, and lyse tumor cells in an antibody-independent manner. We have found that tumor cells pretreated with phorbol esters are no longer susceptible to macrophage-mediated cytolysis, although the initial binding step is unaffected. The non-promoting derivatives, 4-beta-phorbol and 4LPDD, were inactive in protecting against cytolysis, and TPA did not protect tumor cells from lysis by antibody plus complement. Since the phorbol ester receptor has been identified as protein kinase C in other cells, a search was initiated for substrates phosphorylated only in the presence of phorbol esters. Preliminary findings indicate that proteins of Mr = 47, 60, and 140 kilodaltons are substrates for TPA-induced phosphorylation. This suggests a possible mechanism for the resistance of phorbol ester-treated tumor cells to macrophage-mediated cytolysis. (MB)

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA018672-10
Application #
3165020
Study Section
Experimental Immunology Study Section (EI)
Project Start
1987-01-01
Project End
1989-12-31
Budget Start
1987-01-01
Budget End
1987-12-31
Support Year
10
Fiscal Year
1987
Total Cost
Indirect Cost
Name
St. Jude Children's Research Hospital
Department
Type
DUNS #
067717892
City
Memphis
State
TN
Country
United States
Zip Code
38105
Fishman, M (1991) Cytolytic activities of activated macrophages versus paraformaldehyde-fixed macrophages;soluble versus membrane-associated TNF. Cell Immunol 137:164-74
Bysani, G K; Stokes, D C; Fishman, M et al. (1990) Binding of polymyxin B to rat alveolar macrophages. J Infect Dis 162:939-43
Fishman, M; Essani, N; Costlow, M (1990) TPA induction of EL4 resistance to macrophage-released TNF: role of ADP-ribosylation in tumoricidal activities of TNF and other factors. Cell Immunol 127:78-91
Brown, A R; Fishman, M (1990) Tumor necrosis factor-alpha analyzed within individual macrophages by combined immunocytochemistry and computer-aided image analysis. Cell Immunol 130:352-63
Nycum, L M; Fishman, M (1989) The effect of phorbol esters on tumor cell sensitivity to macrophage-mediated cytostasis. Cell Immunol 118:147-56
Stokes, D C; Shenep, J L; Fishman, M et al. (1989) Polymyxin B prevents lipopolysaccharide-induced release of tumor necrosis factor-alpha from alveolar macrophages. J Infect Dis 160:52-7
Essani, N; Fishman, M (1988) Induction of EL4 cell resistance to syngeneic macrophage-mediated lysis by protein kinase C ligands;effects of cultured TPA-treated target cell and protein phosphorylation. Immunology 65:165-70
Fishman, M; Gunther, G (1986) Induction of tumor cell resistance to macrophage-mediated lysis by preexposure to non-activated macrophages. Cell Immunol 99:241-56
Thomas, E L; Fishman, M (1986) Oxidation of chloride and thiocyanate by isolated leukocytes. J Biol Chem 261:9694-702