DNA content and chromatin texture of benzo[a]pyrene-transformed human breast epithelial cells as assessed by image analysis.
DNA content and chromatin supraorganization defined in terms of patterns of chromatin texture were studied by image analysis in Feulgen-stained human breast MCF-10F epithelial cells expressing different stages of tumorigenic progression after treatment with benzo[a]pyrene (BP). Nontransformed MCF-10F, nontumorigenic transformed BP1, and tumorigenic BP1-E1 cell lines were analyzed. A relationship between changes in DNA content and chromatin texture and the expression of different stages of tumorigenesis were researched in interphase nuclei. A significant decrease in Feulgen-DNA amounts and absorbing areas suggesting aneuploidy, and first detected in nontumorigenic transformed BP1 cells, became more relevant in the tumorigenic cell line BP1-E1. Simultaneously, an increase in optical densities and a change in related parameters, demonstrating increased chromatin higher order packing states, occurred in transformed BP1 cells and extended over larger chromatin areas in tumorigenic BP1-E1 cells. The results indicate loss of DNA and a change in chromatin higher order packing states accompanying the expression of different stages of the in vitro tumorigenesis process in BP-transformed human breast epithelial cells. It is suspected that the gradually acquired chromatin "condensation" supraorganization pattern is associated with activated transcription activities previously suggested for these cells.
de Campos Vidal
B
B
Department of Cell Biology, Institute of Biology, Campinas, 13083-970, Brazil.
Russo
J
J
Mello
M L
ML
D001564:Benzo(a)pyrene; D001940:Breast / Q000378:metabolism* / Q000473:pathology; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000473:pathology; D002843:Chromatin / Q000378:metabolism* / Q000473:pathology; D004273:DNA, Neoplasm / Q000187:drug effects / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015591:Microspectrophotometry
D002843:Chromatin; D004273:DNA, Neoplasm; D001564:Benzo(a)pyrene