DNA demethylation is directly related to tumour progression: evidence in normal, pre-malignant and malignant cells from uterine cervix samples.
A computer-assisted assay based on the quantitative analysis of DNA methylation in individual interphase nuclei by indirect immunolabelling with anti-5-methylcytosine antibodies was recently developed in our laboratory. In situ analyses were performed on individual nuclei from normal and experimentally hypo- or hypermethylated cultured cells as well as on human peripheral blood B-lymphocytes from normal and chronic lymphoid leukemia (CLL) samples. We present the results obtained on cells from patients affected by different degrees of preneoplastic or neoplastic changes of the uterine cervix as compared to normal controls. The analysis of DNA methylation in individual cells from cytofuge samples was performed as follows: within each nucleus the eu- and heterochromatin methylation levels were quantified in the grey scale range by dedicated software in terms of numbers, areas and optical densities (ODs) of the immunolabeled dense heterochromatic regions ("spots"), and of the optical density of nuclear background, i.e., of nuclear euchromatin. Analogously, in randomly chosen microscope fields of tissue sections from paraffin-embedded samples, progressive tissue demethylation was observed in dysplastic and cancer cells as compared to normal ones. Both methods showed significant and progressive DNA hypomethylation in dysplastic and cancer cells as compared to control specimens.
de Capoa
Adriana
A
Department of Genetics and Molecular Biology, Universita di Roma 1, La Sapienza, Via dei Sardi 70, 00185 Rome, Italy. adriana.decapoa@uniroma1.it
Musolino
Angelina
A
Della Rosa
Simonetta
S
Caiafa
Paola
P
Mariani
Luciano
L
Del Nonno
Franca
F
Vocaturo
Amina
A
Donnorso
Raffaele Perrone
RP
Niveleau
Alain
A
Grappelli
Claudio
C
D044503:5-Methylcytosine / Q000032:analysis* / Q000276:immunology; D000328:Adult; D000911:Antibodies, Monoclonal / Q000032:analysis; D002278:Carcinoma in Situ / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D002584:Cervix Uteri / Q000378:metabolism / Q000473:pathology; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000378:metabolism*; D018450:Disease Progression; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D011230:Precancerous Conditions / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D014594:Uterine Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
D000911:Antibodies, Monoclonal; D004273:DNA, Neoplasm; D044503:5-Methylcytosine