Nerve growth factor receptors in chromatin of melanoma cells, proliferating melanocytes, and colorectal carcinoma cells in vitro.

Nuclear localization of nerve growth factor (NGF) in HS 294 melanoma cells and SW 707 colorectal carcinoma was determined by indirect immunofluorescence staining and by cell fractionation. NGF receptors were immunoprecipitated from the EcoRI-digested chromatin of HS 294 melanoma cells, of melanocytes proliferating in the presence of 12-O-tetradecanoylphorbol-13-acetate, and of SW 707 colorectal carcinoma cells, using a monoclonal antibody to the Mr 75,000 cell surface NGF receptor. Melanoma cells expressed a receptor species with a molecular weight of 230,000. Proliferating melanocytes expressed a small amount of Mr 230,000 receptor, whereas colorectal carcinoma cells expressed a Mr 35,000 receptor. Scatchard analysis indicated one type of NGF chromatin binding site in HS 294 cells with KD = 241 pM but two types of binding sites in chromatin of SW 707 cells with KD = 333 and 1718 pM, respectively. Both the Mr 230,000 and the 35,000 receptor species were tightly bound to DNase II-sensitive regions, which became DNase II-insensitive after nerve growth factor binding. [125I]NGF was detected in the chromatin in nondegraded form. Chromatin binding of NGF inhibited RNA synthesis and cell proliferation.