We are working towards a complete understanding of the interaction of melanotropin (MSH) with its receptors and the way in which the proliferation and pigmentation of normal and malignant pigment cells are controlled. We want to identify the genes for the MSH receptor, for tyrosinase and for proteins affected by the phorbol ester TPA, a factor needed for the growth of normal and some malignant melanocytes in culture. We have improved on our previous procedure for preparing ?125?I-Beta-MSH and now obtain yields approximately 10-fold higher and can store the product approximately 4-fold longer than before. We developed three assays for detecting the binding of MSH to intact melanoma cells and/or homogenates. Two of the assays can also be used to detect receptors in soluble form, that is, free of other membrane components. The third assay will be useful in screening the supernatants of hybridomas for monoclonal antibodies towards the MSH receptor because it permits the completion of several hundred tests per day. We extended our studies on the expression of receptors for MSH during the cell cycle. We reported previously that receptors for MSH on Cloudman melanoma cells were active primarily during the late S-phase and in the G2-phase of the cell cycle. Because this time period represents only about 5 to 10% of the cell cycle, only 5 to 10% of the cells in non-synchronized, randomly growing populations would be expected to bind and respond to MSH. We have, therefore, partially synchronized the cultures and found that cells passing through late S and G2 synchronously, following their release from a colchicine- or thymidine-induced block, bind not 10 times but 100 times more MSH than do those in random cultures. This increased binding capacity is due to an increase in both the number and the affinity of receptors for MSH. (B)

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA004679-27
Application #
3163180
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1976-12-01
Project End
1987-03-31
Budget Start
1986-04-01
Budget End
1987-03-31
Support Year
27
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Yale University
Department
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Halaban, R; Tyrrell, L; Longley, J et al. (1993) Pigmentation and proliferation of human melanocytes and the effects of melanocyte-stimulating hormone and ultraviolet B light. Ann N Y Acad Sci 680:290-301
Halaban, R; Fan, B; Ahn, J et al. (1992) Growth factors, receptor kinases, and protein tyrosine phosphatases in normal and malignant melanocytes. J Immunother (1991) 12:154-61
Halaban, R; Funasaka, Y; Lee, P et al. (1991) Fibroblast growth factors in normal and malignant melanocytes. Ann N Y Acad Sci 638:232-43
Halaban, R (1991) Growth factors regulating normal and malignant melanocytes. Cancer Treat Res 54:19-40
Halaban, R (1991) Growth factors and tyrosine protein kinases in normal and malignant melanocytes. Cancer Metastasis Rev 10:129-40
Daniolos, A; Lerner, A B; Lerner, M R (1990) Action of light on frog pigment cells in culture. Pigment Cell Res 3:38-43
Halaban, R; Moellmann, G (1990) Murine and human b locus pigmentation genes encode a glycoprotein (gp75) with catalase activity. Proc Natl Acad Sci U S A 87:4809-13
Stenn, K S; Link, R; Moellmann, G et al. (1989) Dispase, a neutral protease from Bacillus polymyxa, is a powerful fibronectinase and type IV collagenase. J Invest Dermatol 93:287-90
Kwon, B S; Haq, A K; Wakulchik, M et al. (1989) Isolation, chromosomal mapping, and expression of the mouse tyrosinase gene. J Invest Dermatol 93:589-94
Dotto, G P; Moellmann, G; Ghosh, S et al. (1989) Transformation of murine melanocytes by basic fibroblast growth factor cDNA and oncogenes and selective suppression of the transformed phenotype in a reconstituted cutaneous environment. J Cell Biol 109:3115-28

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