Nucleic acid content and cell cycle distribution of five human bladder cell lines analysed by flow cytofluorometry

Five human bladder cell lines, four derived from tumor tissue and the fifth originating from presumed benign transitional epithelium, were examined by flow cytofluorometry to estimate the DNA and RNA content per cell during exponential and stationary phases of growth. A new staining technique was employed using acridine orange to differentially stain DNA and RNA in unfixed cells made permeable to the dye and other reagents by treatment with detergent at low ph. Stemline chromosome numbers for each cell line correlated well with relative DNA content of the G1 population as measured by this technique. In addition, the simultaneous measurements of DNA and RNA per cell yielded cell cycle distributions for each cell line. The ratio of stainable RNA/DNA was lower for all cell lines derived from bladder tumors as compared to the presumed normal cell line, indicating high nuclear/cytoplasmic ratios for the former.