Differential growth factor responses of epithelial cell cultures derived from normal human prostate, benign prostatic hyperplasia, and primary prostate carcinoma.

Abstract

Because of a lack of information of the optimum nutritional requirements, epithelial cells derived from normal human prostate and prostate tumors have been difficult to propagate in vitro, which hinders research in prostate carcinogenesis. In an effort to establish optimum nutritional conditions and differences in growth characteristics of normal human prostate (NP), benign prostatic hyperplasia (BPH), and prostatic carcinoma (PCA), we have compared the effects of several growth factors on cell proliferation and elucidated growth properties of low passage epithelial cells derived from NP, BPH, and PCA of an African-American patient. Primary and low passage cultures were propagated in serum-free keratinocyte basal medium (KBM) supplemented with insulin (5 micrograms/ml), hydrocortisone (0.5 microgram/ml), epidermal growth factor (EGF, 10 ng/ml), bovine pituitary extract (BPE; 50 micrograms/ml), cholera toxin (10 ng/ml), and antibiotics. Almost all NP, BPH, and PCA cells were positive for cytokeratins and prostate-specific antigen (PSA). The NP, BPH, and PCA cells were essentially diploid and lacked mutations in c-K-ras and c-Ha-ras oncogenes, and p53 tumor suppressor gene. However, they exhibited progressively accelerating growth parameters. The population doubling times of NP, BPH and PCA were 51 hr, 37 hr, and 29 hr, respectively; their saturation densities were 2.9 x 10(4)/cm2, 3.3 x 10(4)/cm2, and 7.2 x 10(4)/cm2, respectively. The NP and BPH cells required all of the growth factors in the medium, as deletion of any one of the above factors strongly inhibited their growth. The PCA cells, however, were independent of EGF and hydrocortisone. PC-3, an established human prostate cancer cell line, was independent of the growth factors tested. Fetal bovine serum (FBS) inhibited the growth of NP, BPH and PCA cells. In contrast, FBS stimulated the growth of the PC-3 cells in a concentration-dependent manner. These results indicate that in the absence of any apparent karyotype alterations and mutations in c-K-ras, c-Ha-ras and p53 genes, epithelial cells derived from NP, BPH, and PCA exhibit significant differences in their growth properties and responses to growth factors. These variations may represent early changes involved in prostate cancer, while gene mutations and cytogenetic alterations occur in advanced and/or metastatic tumors.