epidermal-growth-factor and mibolerone

The study of prostate carcinogenesis and tumor progression is made difficult by the lack of appropriate in vitro and in vivo models. High prevalence of prostatic intra-epithelial neoplasia and latent prostatic carcinoma, representing multiple steps in carcinogenesis to invasive carcinoma, are relevant targets for cancer prevention. From the RWPE-1, immortalized, non-tumorigenic, human prostate epithelial cell line, we have derived four tumorigenic cell lines with progressive malignant characteristics.. Cell lines were derived by exposure of RWPE-1 to N-methyl-N-nitrosourea (MNU), selected and cloned in vivo and in vitro, and characterized by prostatic epithelial and differentiation markers, karyotype analysis, anchorage-independent growth, invasiveness, tumorigenicity, and pathology of the derived tumors.. Cytokeratins 8 and 18, androgen receptor, and prostate-specific antigen expression in response to androgen, confirm prostatic epithelial origin. RWPE-1 cells do not grow in agar and are not tumorigenic in mice, but the growth, tumorigenicity, and tumor pathology of the MNU cell lines correlate with their invasive ability. The WPE1-NA22 (least malignant) form small, well-differentiated, and WPE1-NB26 cells (most malignant) form large, poorly differentiated, invasive tumors. Overall, loss of heterozygosity for chromosomes 7q, 13q, 18q, and 22, and gain of 5, 9q, 11q, and 20, was observed. The MNU cell lines, in order of increasing malignancy are; WPE1-NA22, WPE1-NB14, WPE1-NB11, and WPE1-NB26.. This family of cell lines with a common lineage represents a unique and relevant model which mimics stages in prostatic intra-epithelial neoplasia (PIN) and progression to invasive cancer, and can be used to study carcinogenesis, progression, intervention, and chemoprevention.

Topics: Alkylating Agents; Animals; Carcinogenicity Tests; Cell Adhesion; Cell Culture Techniques; Cell Division; Chromosome Aberrations; Chromosome Disorders; Disease Progression; Dose-Response Relationship, Drug; Epidermal Growth Factor; Humans; Keratins; Male; Methylnitrosourea; Mice; Mice, Nude; Nandrolone; Neoplasm Invasiveness; Prostate-Specific Antigen; Prostatic Neoplasms; Receptors, Androgen; Transforming Growth Factor beta; Tumor Cells, Cultured

Previous studies from this laboratory indicated a role for epidermal growth factor (EGF) in androgen-dependent male sexual differentiation. The mechanism by which EGF modulates male sexual differentiation has not been determined and investigation has been made to assess the role for androgen receptor (AR) in mediating the EGF-induced effect. We report that EGF, like androgen, stabilized the Wolffian duct in the 13-day female specimen, grown in organ culture. Anti-AR, flutamide and cyproterone acetate blocked the Wolffian duct-stabilizing effect of EGF. EGF also induced cell proliferation of the fetal reproductive tract in a dose-dependent manner and a combination of physiological dosages of EGF and androgen-induced cell proliferation synergistically, suggesting an interactive effect of these two drugs. Cyproterone acetate blocked both EGF-induced normal cell proliferation and the synergistic cell proliferation induced by combination of EGF and androgen suggesting a role of AR in the effects of EGF. The role of AR was further assessed by determining the effect of EGF on AR binding directly. It was shown that EGF stimulated androgen binding activity of the male fetal reproductive tract cells significantly by increasing the number of binding sites by 3-fold with slight decrease in binding affinity. Thus, it appears that AR plays a role in mediating EGF-modulation of sexual differentiation.

Topics: Animals; Cell Division; Cyproterone Acetate; Drug Interactions; Epidermal Growth Factor; Female; Genitalia, Female; Genitalia, Male; Gestational Age; Male; Mice; Nandrolone; Organ Culture Techniques; Receptors, Androgen; Sex Differentiation; Testosterone; Testosterone Congeners; Wolffian Ducts

The present study was undertaken to compare the relationship between response to exogenous epidermal growth factor (EGF) and the expression of the EGF-receptor (EGF-R) in an androgen sensitive (LNCaP) and insensitive (DU145) prostate cancer cell line. Although both cell lines demonstrated a single EGF-R binding site of similar high affinities (mean dissociation constant (Kd) +/- S.D. for DU145 = 1.0 +/- 0.6 nmol l-1; LNCaP = 2.8 +/- 2.2 nmol l-1) the number of binding sites (RT) for the hormone insensitive DU145 cells (mean +/- S.D. = 2.5 +/- 1.0 x 10(5) sites/cell) and 10-fold greater than that expressed in the androgen responsive LNCaP cell line (mean +/- S.D. = 2.0 +/- 1 x 10(4) sites/cell). Additionally exogenous EGF only minimally affected the growth and DNA synthesis of DU145 cells whereas LNCaP cells showed a significant response which was dose dependent. The autologous production of EGF-like molecules by DU145 cells is believed to reduce the cells needs for exogenous mitogens, thereby rendering the cells autostimulatory. Treatment of LNCaP cells with Mibolerone--a synthetic androgen--did not affect either the expression of the EGF receptor or the proliferative response observed with EGF. Western blot analysis, using monoclonal antibodies directed against the EGF receptor revealed a band of approximately 170 kD with DU145 cell lysates but the LNCaP EGF receptor was not detected using this technique.

Topics: Blotting, Western; Cell Division; DNA, Neoplasm; Epidermal Growth Factor; ErbB Receptors; Humans; Male; Nandrolone; Prostatic Neoplasms; Thymidine; Tumor Cells, Cultured