Effect of molybdate on androgen receptor levels in canine prostate

A comparative study on the stabilizing effect of sodium molybdate on androgen receptors was performed using canine prostates. Prostates from intact male dogs of mixed breeds were run in parallel sucrose density gradient analyses, using buffer systems with or without molybdate. Prostates that were homogenized in a molybdate buffer showed a significant increase in androgen receptor content relative to those in a molybdate-free system.     

Metioprim-sulphadiazine distribution in the canine prostate

Constant infusion experiments with metioprim and sulphadiazine were performed in four anesthesized dogs to determine the drugs' concentrations in prostatic secretion, prostatic interstitial fluid, prostatic tissue, urine, and serum. Metioprim showed a specific affinity for the prostate gland, whereas sulphadiazine, as expected, demonstrated lower values in prostatic secretion and tissue than in serum. The prostatic secretion: serum and prostatic tissue:serum ratios using a high-pressure liquid chromatography assay of metioprim were 7.3 and 4.0, respectively. Furthermore, metioprim showed 3.6 to 5.7 times higher concentrations in the organs of the urogenital system, liver, lung, and pancreas than in serum. We suggest that metioprim may be useful in the treatment of bacterial prostatitis, considering its spectrum of antibacterial activity and the data presented in this study.     

Transrectal ultrasonotomography of the canine prostate

We developed a new scanner for transrectal ultrasonotomography of the canine prostate. Using this scanner, a clear horizontal tomogram of the canine prostate was obtained for cross sections at every 2 mm. Prostatic volume was estimated as the sum of the volume of each section. Accordingly, the weight of the canine prostate could be accurately calculated from the volume and the specific gravity of the prostate.     

Effect of prostatic neuropeptides on migration of prostate cancer cell lines

BACKGROUND: A previous study by the same authors demonstrated that among various neuropeptides in the prostate, calcitonin gene-related peptide (CGRP) and gastrin-releasing peptide (GRP) increased the invasive capacity of PC-3 prostate cancer cells through enhancement of cell motility, while substance P (SP) inhibited the invasiveness through suppression of motile response. METHODS: The effect of 10 kinds of neuropeptides were investigated, including CGRP, GRP, SP, neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calcitonin (CT), leucine-enkephalin (L-ENK), methionine-enkephalin (M-ENK), glucagon and parathyroid hormone-related protein (PTH-rP), on the invasion of DU-145 prostate cancer cells through a reconstituted basement membrane (Matrigel) and the haptotactic migration of DU-145, TSU-pr1 and LNCaP prostate cancer cells using a Transwell cell culture chamber assay. RESULTS: It was found that GRP, CGRP and PTH-rP increased the invasive capacity of tumor cells. In contrast, SP, VIP, CT, L-ENK, M-ENK, NPY and glucagon had no significant effect. These three neuropeptides also increased the haptotactic migration of tumor cells to fibronectin. In addition VIP, CGRP and GRP increased the haptotactic migration of LNCaP prostate cancer cells and GRP and PTH-rP increased the migration of TSU-pr1 cells. CONCLUSION: The results indicated that some prostatic neuropeptides increased the invasive potential of prostate cancer cells partially through enhancement of cell motility.     

Polarity of prostate specific membrane antigen,prostate stem cell antigen,and prostate specific antigen in prostate tissue and in a cultured epithelial cell line

BACKGROUND: Madin-Darby canine kidney (MDCK) cells are immortalized epithelial cells that have been used extensively as a model system to study intracellular molecular trafficking, polarized expression, and secretion of proteins in various epithelia. In order to determine if MDCK cells might serve as a model to study molecular events within prostate epithelial cells, we have evaluated the polarized distribution of three prostate restricted proteins, PSMA, PSCA, and PSA, in situ, and in MDCK cells. METHODS: Using immunofluorescence, confocal microscopy, cell surface biotinylation, antibody internalization, and biochemical assays we evaluated surface expression and secretion of three prostate restricted proteins expressed in MDCK cells. We compared these patterns of expression to results observed within prostatic epithelium. RESULTS: We demonstrate that PSMA is localized primarily to the apical plasma membrane in both the prostatic epithelium and transfected MDCK cells, whereas PSCA is expressed in a non-polarized fashion. We also show that PSA is secreted predominantly from the apical surface of transfected MDCK cells, consistent with in vivo observations. CONCLUSIONS: Similar patterns of localization among MDCK and prostatic epithelial cells suggest that the mechanisms of polarized sorting within these cell types are conserved. Thus, MDCK cells offer a useful model system to study mechanisms of targeting of these proteins within the prostate.     

Penicillanic acid derivatives in the canine prostate

Distribution of ampicillin, amoxicillin, bacampicillin, mecillinam, pivmecillinam, carbenicillin, and carbenicillin indanyl sodium was studied in the canine prostate, prostatic interstitial fluid, and prostatic secretion. All seven antibiotics were found in higher concentrations in the prostatic interstitial fluid than in the prostatic secretion. As expected for weak acids, drug concentrations in these fluids were always lower than the simultaneous serum concentrations. Tissue penetration was enhanced for the penicillin ester, pivmecillinam, as shown by its prostatic secretion/ serum and tissue/serum ratios, which were higher than those of the other antibiotics, including the esters, bacampicillin, and carbenicillin indanyl sodium. This result may be due to pivmecillinam's long hydrolysis half-life. The concentrations for these penicillanic acid derivatives in prostatic interstitial fluid were above the minimal inhibitory concentrations for most of the commonly encountered gram-negative bacteria encountered in prostatitis. Therefore, these antibiotics should be effective in the treatment of bacterial prostatitis caused by susceptible organisms. Carbenicillin and carbenicillin indanyl sodium had the highest prostatic interstitial fluid/serum ratios of the compounds tested, and theoretically, therefore, they should be the most effective in the treatment of prostatitis. However, clinical trials should be carried out to confirm this.     

Electrophoretic marker of differentiated human prostate secretory epithelial cells

Electrophoretic analysis of primordial human prostate epithelium, glandular secretory epithelium of prostate and other human tissues revealed a marker characteristic of differentiated secretory prostate cells. Being probably neither protein nor lipid in chemical nature, this marker reacted in a peculiar way with Amido Black 10B. The marker was shown to be present in prostatic secretory substance.     

Genistein-induced neuroendocrine differentiation of prostate cancer cells

BACKGROUND: Neuroendocrine (NE) cells are present in normal prostate and their number appears to be increased in advanced prostate cancer (PCA). In this study, we studied the effect of the phytoestrogen, genistein, on NE differentiation of LNCaP cells in vitro. METHODS: Neuroendocrine marker expression of LNCaP cells exposed to genistein was measured by immunohistochemistry, Western blot, and real-time PCR methods. Western blot analysis was used to study cell cycle and signaling pathways induced by genistein treatment. RESULTS: Six days after continuous genistein treatment, the majority of genistein-surviving cancer cells underwent transdifferentiation into a NE-like phenotype overexpressing the NE markers chromogranin A, synaptophysin, serotonin, and beta-III tubulin. This NE differentiation process was associated with upregulation of the cell cycle modulators p21, p27, and p53, and activation of the MAPK and STAT3 pathways. CONCLUSION: Our data indicate that genistein evokes not only apoptosis but also NE transdifferentiation of PCA cells.     

miR-152对前列腺癌细胞株迁移和侵袭能力的影响

目的研究miR-152在前列腺癌、前列腺正常组织中的表达情况及其在前列腺癌细胞系中的作用。方法采用TaqMan荧光定量RT—PCR方法检测8例前列腺癌和8例前列腺正常组织的样本中miR-152的表达水平。运用Transwell细胞迁移实验及侵袭实验评估miR一152对前列腺细胞系PC-3和DU145细胞功能的影响。结果与正常前列腺组织相比,miR-152在前列腺癌组织中的表达水平显著下调（P〈0．05）。体外实验中上调miR152的表达可以显著降低前列腺癌细胞的迁移和侵袭能力（P〈O．05）。结论miR-152在前列腺癌中可作为一种肿瘤抑制因子,影响前列腺癌细胞的迁移和侵袭能力。     

Secretion of bromide by the canine prostate

Four dogs with surgically produced prostatic fistulas were given single oral doses of 1.13 gm of sodium bromide daily for five consecutive days. Two days later the mean (+/- SE) serum level of bromide was 28.0 +/- 4.0 meq/L and the serum chloride level had decreased from a pretreatment value of 112.5 +/- 1.0 meq/L to 86.5 +/- 3.7 meq/L; in the basal prostatic secretion, the mean prostatic fluid to serum (PF/S) ratios for bromide and chloride were 0.56 +/- 0.15 and 0.53 +/- 0.11, respectively, and were not different (P greater than 0.05, paired t-test); at higher rates of secretion provoked by intravenous pilocarpine the corresponding PF/S ratios of 1.48 +/- 0.04 and 1.32 +/- 0.01 were significantly different (P less than 0.05, paired t-test). It is concluded that the processes involved in forming the basal and pilocarpine-induced prostatic secretions must differ and that the ability of the chloride-transporting system to transport bromide is slightly greater than that for chloride. Because it may impair sperm motility, bromide secreted in prostatic fluid potentially could adversely affect reproduction.     

Studies of a vascular-acting photosensitizer, Pd-bacteriopheophorbide (Tookad), in normal canine prostate and spontaneous canine prostate cancer

BACKGROUND AND OBJECTIVES: Photodynamic therapy (PDT) mediated with Tookad (Pd-bacteriopheophorbide, WST09) was investigated pre-clinically as part of a program to develop an alternative modality for treating prostate cancer. STUDY DESIGN/MATERIALS AND METHODS: Spontaneous canine prostate cancer and normal canine prostate were used as the animal models. Interstitial PDT was performed by IV infusion of the photosensitizer and irradiating the prostates with a diode laser (763 nm). The prostates were harvested 1-week post-PDT and subjected to histopathologic examinations. The effects of the drug doses and light doses were studied for one- and two-session PDT. Pharmacokinetics were studied using HPLC assay. The feasibility of using perfusing CT scans for assessing PDT lesions was also evaluated. RESULTS: Tookad is a vascular-acting drug and clears rapidly from the circulation. Tookad-PDT-induced lesions, in both normal and cancerous prostates, were characterized by marked hemorrhagic necrosis. CONCLUSIONS: Tookad-PDT is very effective in ablating prostatic tissue through its vascular effects.     

Melatonin reduces prostate cancer cell growth leading to neuroendocrine differentiation via a receptor and PKA independent mechanism

BACKGROUND: Melatonin, the main secretory product of the pineal gland, inhibits the growth of several types of cancer cells. Melatonin limits human prostate cancer cell growth by a mechanism which involves the regulation of androgen receptor function but it is not clear whether other mechanisms may also be involved. METHODS: Time-course and dose-dependent studies were performed using androgen-dependent (LNCaP) and independent (PC3) prostate cancer cells. Cell number, cell viability, and cell cycle progression were studied. Neuroendocrine differentiation of these cells was evaluated by studying morphological and biochemical markers. Finally, molecular mechanisms including the participation of melatonin membrane receptors, intracellular cAMP levels, and the PKA signal transduction pathway were also analyzed. RESULTS: Melatonin treatment dramatically reduced the number of prostate cancer cells and stopped cell cycle progression in both LNCaP and PC3 cells. In addition, it induced cellular differentiation as indicated by obvious morphological changes and neuroendocrine biochemical parameters. The role of melatonin in cellular proliferation and differentiation of prostate cancer cells is not mediated by its membrane receptors nor related to PKA activation. CONCLUSIONS: The treatment of prostate cancer cells with pharmacological concentrations of melatonin influences not only androgen-sensitive but also androgen-insensitive epithelial prostate cancer cells. Cell differentiation promoted by melatonin is not mediated by PKA activation although it increases, in a transitory manner, intracellular cAMP levels. Melatonin markedly influences the proliferative status of prostate cancer cells. These effects should be evaluated thoroughly since melatonin levels are diminished in aged individuals when prostate cancer typically occurs.     

Studies of androgen and estrogen binding in normal canine prostatic tissue and in epithelial and stromal cell lines derived from the canine prostate

Androgen and estrogen binding to cytosol proteins was examined in preparations derived from canine prostatic tissue and from epithelial and fibroblastoid cell lines. Binding parameters were characterized by saturation analysis using a protamine sulfate precipitation procedure and by analysis of the mobility of steroid-binding moieties in sucrose density gradients. Androgen-binding studies demonstrated the presence of a single class of high-affinity binding component (kD = 1-2 × 10^?9 M), with specificity for 5α-dihydrotestosterone, in cytosols derived from tissue homogenates and both cell types. In estrogen-binding studies two discrete classes of binding component were characterized of high (kD = 5-10 × 10^?10 M) and moderate (kD = 1-2 × 10^?8 M) affinities. Both species were present in cytosol derived from all three sources. The high-affinity component displayed specificity for estradiol-17β, and the second component displayed some capacity for androgen binding. These findings are discussed with reference to the anomalous actions of some androgens in the canine prostate and in relation to the putative role of steroids in stromal-epithelial interrelationships.