GENERATION AND GENETIC-CHARACTERIZATION OF IMMORTAL HUMAN PROSTATE EPITHELIAL-CELL LINES DERIVED FROM PRIMARY-CANCER SPECIMENS

Difficulty in establishing long-term human prostate epithelial cell li nes has impeded efforts to understand prostate tumorigenesis and to de velop alternative therapies for prostate cancer, In the current study, we describe a method that was successful in generating 14 immortal be nign or malignant prostate epithelial cell cultures from primary adeno carcinomas of the prostate resected from sir successive patients, Immo rtalization with the E6 and E7 transforming proteins of human papillom a virus serotype 16 was necessary to establish long-term cultures, Mic roscopic examination of fresh tumor specimens exhibited a variable mix ture of benign and malignant epithelium. Thus, single-cell cloning of tumor-derived cell cultures was essential for defining tumor cell line s, Efforts to characterize these cultures using traditional criteria s uch as karyotype, growth in nude mice, and prostate-specific antigen e xpression were noninformative, However, allelic Loss of heterozygosity (LOH) represents a powerful alternative method for characterizing tum or cell lines originating from primary adenocarcinomas of the prostate , Microdissected fresh tumors from four of sis patients revealed LOH a t multiple loci on chromosome 8p, as assessed by PCR, LOH on chromosom e 8p matching the patterns found in microdissected tumors was also obs erved in a tumor-derived cell line and its clones, as well as in one c lone from a tumor-derived cell line from a second patient, LOH was not observed in immortal lines generated from autologous benign prostatic epithelium, seminal vesicle epithelium, or fibroblasts, The multifoca l nature of prostate cancer, as well as the presence of an entire spec trum of malignant transformation within individual prostate glands, ne cessitates this type of careful analysis of derivative cell cultures f or their validation as in vitro models that accurately reflect the pri mary cancers from which they are derived.