Morphological changes and apoptosis in radial growth phase XXXX cell lines following ultraviolet-B irradiation.

@entity1 @entity588 @entity1373 @entity4311 @entity876 @entity320
BACKGROUND: Knowledge about the morphologic changes following ultraviolet irradiation in the earliest stages of @entity320 is still lacking. METHODS: To investigate these changes, an in vitro system consisting of radial growth phase @entity320 cell lines ( @entity1 and WM3211) was established. Cells were irradiated with a single erythemogenic dose of UVB (10 mJ/cm2) and evaluated for morphologic changes. RESULTS: When compared with the non-irradiated cells, inverted light microscopy revealed increased cellular branching, cytoplasmic size, and multinucleation in the irradiated cells. Transmission electron microscopy revealed the features of increased metabolic activity ( @entity1373 of the mitochondria and Golgi) and those of ultrastructural atypia (pleomorphism of the nuclei and nucleoli, increased euchromatin, and nucleolar margination) in the irradiated cells. Moreover, UVB irradiation caused an increase in the apoptotic activity. These alterations were associated with up-regulation of @entity876 , @entity588 , and the second mismatch repair protein ( @entity4311 ), as revealed by Western blot analysis. CONCLUSIONS: UVB irradiation can induce apoptosis, morphologic changes, and altered expression of @entity876 , @entity588 , and @entity4311 in radial growth phase @entity320 cell lines. Up-regulation of @entity876 , @entity588 , and @entity4311 suggests that these factors are involved in the altered balance between survival and apoptosis induced by UVB. Further investigation will be needed to determine if apoptosis and ultrastructural atypia reflect underlying DNA damage and genomic instability induced by UVB.
