The cytogenetic evolution of the prostatic adenocarcinoma cell line LNCaP was investigated during long term in vitro culture. Study of five different sublines demonstrated that the original karyotype was well preserved in all sublines, with respect to the chromosome number as well as to the primary markers. All sublines showed additional, subline specific secondary marker chromosomes. Comparison of these markers in androgen responsive and nonresponsive sublines showed rearrangement of the short arm of chromosome 8 in both unresponsive sublines. The breakpoints were in 8p21 and 8p23, respectively, resulting in deletion of the 8p23----pter region in both sublines. In contrast, the hormone responsive sublines did not show any aberrations in chromosome 8. Review of published karyotypes of patients and cell lines seems to support our finding of partial deletion of 8p in androgen unresponsive prostate tumor cells.

The effects of prostate fibroblast conditioned medium on two prostate epithelial cell lines (PC-3, LNCaP) and on two non-prostatic cell lines (MCF-7, K562) was investigated. As prostate fibroblast conditioned medium exerts its main effect on DNA synthesis, 3H thymidine incorporation was monitored to measure factor activity. Conditioned media of all prostatic fibroblast lines investigated were inhibitory for PC-3, LNCaP and MCF-7. Conditioned medium of prostatic fibroblasts was clearly stimulatory for K562. Prostate specificity of production of PEIF was demonstrated by the fact that conditioned medium from skin fibroblasts proved to be stimulatory for PC-3. Inhibitory activity from conditioned medium as well as from a BPH homogenate was precipitated by 33-67% ammonium sulfate. These partly purified fractions were respectively five and ten times as active as "crude" conditioned medium. The physical nature of PEIF (protein or macroglycolipid) as well as the possible function (as a signal messenger between stroma and epithelium) is discussed.