title: Re-expression of differentiated properties in SV40-infected human epidermal keratinocytes induced by 5-azacytidine.
abstract: Infection of human epidermal keratinocytes by the oncogenic virus SV40 leads to progressive inhibition of the normal differentiation process in vitro. Treatment of infected cells with 5-azacytidine (5-aza-CR) over a 24-h period produced a striking enlargement and pronounced flattening of cells within 5-7 days following removal of the agent. This morphological change was accompanied by a several-fold increase in the number of cells staining positively for the cell envelope precursor protein, involucrin, and in the exfoliation of cornified envelope bearing cells from the monolayer. The drug-treated cultures at high passage levels were stained by immunofluorescence using monoclonal antibodies to keratin classes associated with different epidermal layers. These experiments revealed that 5-aza-CR caused the re-expression of two keratin classes (suprabasal and stratum corneum-associated), whose synthesis had been suppressed during the transformation process. 5-Aza-CR also brought about re-expression of 58 and 56 kD keratin markers of epithelial keratinization and stratification, as well as of 40 and 49-52 kD keratin markers of viral transformation. However, the responsiveness to the drug was gradually lost over time following infection.
mesh_terms: D001374:Azacitidine / Q000633:toxicity*; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D005467:Floxuridine / Q000633:toxicity; D005455:Fluorescent Antibody Technique; D006801:Humans; D007231:Infant, Newborn; D007633:Keratins / Q000032:analysis; D007700:Kinetics; D008297:Male; D013539:Simian virus 40 / Q000235:genetics*; D012867:Skin / Q000187:drug effects / Q000528:radiation effects; D012879:Skin Physiological Phenomena
chemical_list: D005467:Floxuridine; D007633:Keratins; D001374:Azacitidine