Lack of DNA synthesis among CD34+ cells in cord blood and in cytokine-mobilized blood

Flow cytometric DNA analysis was performed in combination with three-colour immunological staining of cell surface antigens on density-separated mononuclear cells (MNC) obtained from peripheral blood (PB) before, during and after cytokine stimulation of healthy adults. The aim of the study was to determine the cell-cycling status of haemopoietic progenitor cells mobilized into the blood of healthy volunteers during a 5 d treatment period with 5 μg per kg body weight of either granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF). Despite considerably increasing numbers of CD34⁺ PB MNC, the latter were not found to be in S/G₂M phase, whereas, among the CD34^? MNC, the proportion of cells in S/G₂M phase increased from <0.1% to 0.75 ± 0.4% (GM-CSF) and to 1.34 ± 0.75% (G-CSF) and dropped again after discontinuation of the cytokine stimulation. These cells expressed CD33 but were negative for CD45RA, CD3, CD19 and CD14 and were thus considered granulopoietic cells. Analogous results were obtained from analyses of cord blood (CB). In contrast, CD34⁺ cells from bone marrow (BM) were partially (between 9% and 15%) found to be in S/G₂M phase. The non-cycling status of PB and CB progenitor cells was confirmed by the analysis of CD34⁺ cells enriched from the two cell sources. However, in vitro stimulation of these progenitor cells using IL3, GM-CSF, erythropoietin and steel factor (SF) revealed that, after 48 h in suspension culture, up to 30% of the CD34⁺ cells were in S/G₂M phase. The fact that cycling CD34⁺ cells are only detectable in BM but not in PB or CB may suggest different adhesive properties of migrating/mobilized ‘stem cells’ which may require the BM micro-environment for adequate proliferation in vivo     

DNA aneuploidy in prostatic adenocarcinoma: A frequent event as shown by fluorescence in situ DNA hybridization

Fluorescence in situ hybridization (FISH) using specific DNA probes for chromosomes 1, 7, 10, and Y was performed on 53 prostatic tissue samples obtained from 33 radical prostatectomy specimens and two benign control specimens. The 53 samples from carcinomatous prostates included 33 cancerous and 20 noncancerous samples. Additionally, four metastatic lymph node specimens were examined. Clonal chromosome abnormalities were observed in 78% of the tumors studied. They were detected in a higher proportion in stage pT2 and pT3 tumors (86% and 88%, respectively) compared with stage pT1 tumors (25%). No stage pT4 tumor was analyzed. There was evidence of remarkable focal intratumoral heterogeneity documented by the study of two samples from the same tumor in three of six cases. Comparing FISH determined ploidy patterns with DNA flow cytometry (FCM) in 22 samples, FISH showed aneuploidy whereas FCM showed none.     

Selection toward diploid cells in prostatic carcinoma derived cell cultures

For elucidation of the growth-regulatory mechanisms in prostatic carcinoma, in vitro investigations on prostatic cell cultures are required. However, one major problem of cell culturing is the selection of particular cell types such that the cell lines representing only some of the features as compared with the tumor of origin. We studied the chromosomal composition of 20 prostatic tissue-derived cell cultures and 12 original (fresh) tissue specimens that were obtained from 13 patients with prostatic adenocarcinoma. Using fluorescence in situ DNA hybridization (FISH), evident clonal abnormalities were detected in 78% of the fresh cancer samples and in 47% of the cultured cancer samples. Of the seven cases revealing clonal abnormalities in the fresh cancer specimen, aneuploidy was detected in only two samples after cell culturing at the earliest passage studied. The aneuploid cell populations in the cultured samples were all lost during progressive subcultivation (after passage 4). Interestingly, by performing FISH on cytogenetic preparations aneuploidy was confined to the interphases, with the metaphases being found to be diploid. This finding indicates that the aneuploid cells have a proliferation disadvantage in cell culture resulting in an overgrowth of diploid cells. © 1996 Wiley-Liss, Inc.