Preferential loss of abnormal prostate carcinoma cells by collagenase treatment

Abstract

Effects of two different methods of tumor disaggregation on flow cytometric ploidy distribution and intact cell yield were investigated. Either mechanical disaggregation or collagenase digestion was applied to 35 prostate tumor specimens. Seven collagenase-treated samples failed to yield any intact cells, whereas with mechanical disaggregation in all cases a sufficient number of intact cells were obtained. No differences in the FCM ploidy distribution of tumors with a DNA diploid stemline were observed comparing both techniques. In DNA aneuploid tumors, however, collagenase treatment had an adverse effect on the abnormal cell populations. In 14/17 of such tumors, the abnormal cell populations were significantly reduced; in eight of these the percentage of DNA aneuploid cells declined even below the minimum percentage (10%) that was defined for DNA aneuploidy. Since collagenase is a widely used enzyme for tissue disaggregation, especially in tumor cytogenetics, the presented data will have consequences for the interpretation of results obtained by methods involving the use of this enzyme.

Androgen Receptor Expression, Proliferation Index and Aneuploidy in Tissue Explant Cultures Derived Prostate Carcinoma Cells Co-Cultivated on Membranes

“…We had found a preferential growth of diploid cells with loss of the aneuploid cell populations either immediately after cell culture initiation or early during progressive subcultivation. Similar observations were reported by other groups [5,6,13,14].…”

“…Steps Short-term cell culturing of adult human prostatic epithelial cells has been accomplished by a variety of methods [5,6,14,17,31,32,34], but genetic studies indicate loss of aneuploid tumor cells and/or enrichment of diploid cells in most in vitro culture systems reported so far.…”

“…Cytogenetic studies are not suitable for analyzing genetical changes in prostate cancer, because culturing of prostatic carcinoma cells is required for these analyses. This substantially leads to preferential loss of aneuploid/aneusomic clones [5][6][7][8]. Additionally, analysis of metaphase chromosomes catch only a subset of actively proliferating cells with short G1 phases [9].…”

Are primary cultures realistic models of prostate cancer?

“…When sensitive methods such as fluorescence in situ hybridization (FISH) are employed, up to 80% of primary cultures derived from cancers have been reported to have clonal abnormalities [Brothman et al, 1992;Szucs et al, 1994]. The loss of aneuploid cells in culture has been attributed by one group of investigators to collagenase digestion of the tissue [Konig et al, 1993b], and Zwergel et al…”

Gain and loss of chromosomes 1, 7, 8, 10, 18, and Y in 46 prostate cancers

“…3 The ploidy of the different peaks in histograms from tumor samples was calculated from their position, relative to the GO/ G1 peak (C = 2) in a histogram of cultured normal diploid prostate fibroblasts. Diploid: C = 1.9 to 2.2; hypodiploid C 1.8; hyperdiploid C = 2.3 to 2.7; triploid: C = 2.8 to 3.4; tetraploid: C = 3.5 to 4.2.…”