Effect of Dibutyryl Cyclic Adenosine 3',5'-Monophosphate on Morphological Features and Biological Markers of Human Salivary Myoepithelial Cell Line in Culture

Abstract

We have found the emergence of myoepithelial cells (HSG-AZA1) in neoplastic human salivary intercalated duct cell line HSG in culture after treatment with 5-azacytidine. When HSG-ZAZl cells were cultured in the presence of Nt.CP-dibutyryl cyclic adenosine 3',5'-monophosphate (dB-cAMP), they formed long cytoplasmic processes which were densely packed with ample microfibrils in addition to microtubule bundles. The expression of neuron-specific enolase, synap-tophysin, and catecholamine as well as neurofilaments in the treated HSG-AZA1 cells was found by the immunofluorescence staining technique, immunoblotting, immunoelectron microscopy, or catecholamine fluorescence. Both the anchorage-independent and anchorage-dependent growths cfHSG-AZAl cells were suppressed in the presence ofdB-cAMP. After the removal of dB-cAMP from the culture, the treated cells returned rapidly to thephenotype and growth rate of the untreated cells. These findings indicate that reversible differentiation into the neuron-like cells of HSG-AZA1 cells occurs in growth medium containing dB-cAMP.