In vitro phenotypic alteration of human melanoma cells induced by differentiating agents: heterogeneous effects on cellular growth and morphology, enzymatic activity, and antigenic expression.
Sodium butyrate (butyrate), 5-azacytidine (5Aza-C), dimethyl sulfoxide (DMSO), and dimethyl formamide (DMF) were applied to a human melanoma cell line for the purpose of inducing pigmentation and terminal differentiation. The results are summarized as follows: 1) butyrate, DMSO, and DMF had a strong cytostatic effect, arresting cells in the G1 phase of the cycle; 2) butyrate caused a morphological change to spindle shape whereas DMSO and DMF produced rounded cells, without affecting the levels of vimentin and intermediate filaments; 3) tyrosinase activity and melanization were stimulated by DMSO and DMF but not by butyrate; 4) butyrate induced several membrane-bound enzyme activities (alkaline phosphatase and gamma-glutamyl transpeptidase); 5) changes in the expression of antigens related to tyrosinase activity (2B7 and 5C12) only partly corresponded to the changes in enzyme activity; 6) expression of the melanosomal B8G3 antigen was decreased by butyrate, DMSO, and DMF; and 7) the action of DMF resembled that of DMSO whereas 5Aza-C had little effect. The results indicate that these differentiating agents activate different sets of genes, the melanogenic pathway being activated independently of gamma-glutamyltranspeptidase. The down regulation of B8G3 antigen by these agents may provide a common focus for understanding the essential action of differentiation inducers in melanoma cells.
Takahashi
H
H
Queensland Institute of Medical Research, Australia.
Parsons
P G
PG
D000951:Antigens, Neoplasm / Q000032:analysis; D001374:Azacitidine / Q000494:pharmacology*; D002087:Butyrates / Q000494:pharmacology*; D020148:Butyric Acid; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004126:Dimethylformamide / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007700:Kinetics; D008543:Melanins / Q000032:analysis; D008545:Melanoma / Q000201:enzymology / Q000276:immunology / Q000473:pathology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D014442:Monophenol Monooxygenase / Q000378:metabolism; D015388:Organelles / Q000187:drug effects / Q000648:ultrastructure; D010641:Phenotype
D000951:Antigens, Neoplasm; D002087:Butyrates; D008543:Melanins; D020148:Butyric Acid; D004126:Dimethylformamide; D014442:Monophenol Monooxygenase; D001374:Azacitidine; D004121:Dimethyl Sulfoxide