INVITRO CULTIVATION AND CHARACTERIZATION OF HUMAN PROSTATIC-CANCER CELLS

In-vitro cultivation of human prostatic cancer cells was performed usi ng bioptic material obtained by radical prostatectomy. Parallel probes were examined histopathologically. Morphology, proliferation index, E GF-receptor (EGFR) expression and intermediate filament (IF) staining were determined to describe the behavior of prostatic cancer cells in- vitro and to monitor the particular phenotype during subculturing. The cell-lines exhibited a proliferation index between 13 and 65 % (mean value 35.4 %) as determined by Ki-67 staining. In 80% of the examined cell-lines, a positive EGFR expression was found. All corresponding cu ltures obtained from lymph node material were negative, except one lym ph node metastasis, which showed the same EGFR expression as the prost atic cell-lines. These values, the Ki-67 index, as well as the EGFR st aining pattern, remained constant during serial subcultivation. In con trast to these observations, a remarkable shift in cellular morphology from a clear epithelial shape to a more fibroblast-like feature at la te subcultures was observed. The IF-pattern changed to a weak vimentin expression at late subcultures whereas, in p0 to p3 cytokeratins, 8, 18 and 11 were found. We conclude that shifts in gene expression are c aused rather by changes of the extracellular environment than by clone -selection mechanisms during serial subculturing. Thus, with the perma nent cell-lines, an excellent in-vitro system is available to investig ate mechanisms involved in growth control or prostatic cancer cells, e .g. proliferation control, pharmacodynamics or androgen dependence.