[Clonogenicity and BCNU response of subpopulations of human glioma cells sorted according to DNA content].

Malignant gliomas, especially glioblastoma multiforme, are composed of cells that contain various amounts of DNA. We characterized cells dissociated from biopsy specimen of human gliomas by sorting vital cell populations on the basis of DNA content, determined the sensitivity of sorted cells to BCNU, and did the follow-up study using subpopulations cultivated for a long time after sorting on both the DNA histogram and the BCNU response. Seven malignant human gliomas carried in monolayer culture which had three peaks on the DNA histogram were used for this study. To obtain each DNA distribution histogram, cells were stained with chromomycin A 3 and were analyzed with a modified FACS III flow cytometer. Vital DNA was stained with Hoechst 33342 by means of a modification of the procedure of Jovin et al, which involved negligible toxicity to cells. Cells were sorted on FACS III at each peak on the DNA histogram. The colony forming efficiency (CFE) of each population was determined after sorting and surviving fraction was determined after exposure to graded doses (2.5-10 micrograms/ml X 2 hr) of BCNU. Six subpopulations derived from two human glioma cells were cultivated for a long time and reevaluated by both the DNA histogram and the sensitivity to BCNU. The CFEs for each cell population of three peaks on DNA histograms of human glioma cells were similar, except that the CFE for the far left peak (peak 1) in each histogram appeared to be slightly lower in four specimens.(ABSTRACT TRUNCATED AT 250 WORDS)