A novel gelatinolytic enzyme secreted by amelanotic cells isolated from B16 melanoma cell line

Abstract

Mouse B16 melanoma cells are of heterogenous populations and consist of melanotic and amelanotic cells. Two clones, M3 (melanotic) and A7 (amelanotic), were screened from B16 melanoma cells using a microscope, and gelatinolytic activities in these clones were studied with zymography. Gelatinolytic enzyme was found in the cultured medium of A7 cells, but not in M3 cells. The enzymes with apparent molecular weights of 70, 140 and 280 kDa were detected and found to form complexes: a dimer or more than dimer. Their enzyme activities were not inhibited by ethylenediaminetetraacetic acid. The optimal pH of this enzyme was found to be at neutral pH. Preferential expression of this novel gelatinolytic enzyme in amelanotic melanoma will be related to tumorigenic and metastatic phenotype of amelanotic melanoma.