Detection and cloning of a protein recognized by anti-human prostate-specific antigen (PSA) antibody in the rat ventral prostate

Chrysophanic acid reduces testosterone-induced benign prostatic hyperplasia in rats by suppressing 5α-reductase and extracellular signal-regulated kinase

Benign prostatic hyperplasia (BPH) is one of the most common chronic diseases in male population, of which incidence increases gradually with age. In this study, we investigated the effect of chrysophanic acid (CA) on BPH. BPH was induced by a 4-week injection of testosterone propionate (TP). Four weeks of further injection with vehicle, TP, TP + CA, TP + finasteride was carried on. In the CA treatment group, the prostate weight was reduced and the TP-induced histological changes were restored as the normal control group. CA treatment suppressed the TP-elevated prostate specific antigen (PSA) expression. In addition, 5α-reductase, a crucial factor in BPH development, was suppressed to the normal level close to the control group by CA treatment. The elevated expressions of androgen receptor (AR), estrogen receptor α and steroid receptor coactivator 1 by TP administration were also inhibited in the CA group when compared to the TP-induced BPH group. Then we evaluated the changes in three major factors of the mitogen-activated protein kinase chain during prostatic hyperplasia; extracellular signal-regulated kinase (ERK), c-Jun-N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). While ERK was elevated in the process of BPH, JNK and p38 was not changed. This up-regulated ERK was also reduced as normal by CA treatment. Further in vitro studies with RWPE-1 cells confirmed TP-induced proliferation and elevated AR, PSA and p-ERK were all reduced by CA treatment. Overall, these results suggest a potential pharmaceutical feature of CA in the treatment of BPH.

Cinnamomi Cortex (Cinnamomum verum) Suppresses Testosterone-induced Benign Prostatic Hyperplasia by Regulating 5α-reductase

Cinnamomi cortex (dried bark of Cinnamomum verum) is an important drug in Traditional Korean Medicine used to improve blood circulation and Yang Qi. Benign prostatic hyperplasia (BPH) is a common chronic disease in aging men. This study was conducted to determine the effect of Cinnamomi cortex water extract (CC) on BPH. BPH was induced by a pre-4-week daily injection of testosterone propionate (TP). Six weeks of further injection with (a) vehicle, (b) TP, (c) TP + CC, (d) TP + finasteride (Fi) was carried on. As a result, the prostate weight and prostatic index of the CC treatment group were reduced. Histological changes including epithelial thickness and lumen area were recovered as normal by CC treatment. The protein expressions of prostate specific antigen, estrogen receptor α (ERα), androgen receptor (AR), 5α-reductase (5AR), and steroid receptor coactivator 1 were suppressed by treatment of CC. Immunohistochemical assays supported the western blot results, as the expressions of AR and ERα were down-regulated by CC treatment as well. Further in vitro experiments showed CC was able to inhibit proliferation of RWPE-1 cells by suppressing 5AR and AR. These results all together suggest CC as a potential treatment for BPH.

Does PSA play a role as a promoting agent during the initiation and/or progression of prostate cancer?

Prostate cancer cells, like normal prostate epithelial cells, produce high levels of the differentiation marker and serine protease prostate-specific antigen (PSA). PSA is used extensively as a biomarker to screen for prostate cancer, to detect recurrence following local therapies, and to follow response to systemic therapies for metastatic disease. While much is known about PSA's role as a biomarker, only a relatively few studies address the role played by PSA in the pathobiology of prostate cancer. Autopsy studies have documented that not only do prostate cancer cells maintain production of high amounts of PSA but they also maintain the enzymatic machinery required to process PSA to an enzymatically active form. A variety studies performed over the last 10 years have hinted at a role for PSA in growth, progression, and metastases of prostate cancer. A fuller understanding of PSA's functional role in prostate cancer biology, however, has been hampered by the lack of appropriate models and tools. Therefore, the purpose of this review is not to address issues related to PSA as a biomarker. Instead, by reviewing what is known about the genetics, biochemistry, and biology of PSA in normal and malignant prostate tissue, insights may be gained into the role PSA may be playing in the pathobiology of prostate cancer that can connect measurement of this biomarker to an understanding of the underlying etiology and progression of the disease.

Quantitative determination of lobe specificity of mRNA expression of androgen-dependent genes in the rat prostate gland

The rodent prostate has a complex structure, consisting of a ventral prostate (VP), lateral prostate (LP), dorsal prostate (DP) and anterior prostate (AP), and most studies so far have focused on the VP. Androgen-responsive prostatic secretory proteins, such as prostatein and kallikreins, are mainly produced in the VP, but others are abundant in the LP and DP, though little is known about differences of androgen regulation among the different lobes. Here, the mRNA expression levels of some representative androgen-responsive genes, including those encoding prostatic secreted proteins, were quantitatively determined in each of the prostatic lobes of intact rats and castrated rats treated with testosterone alone or plus flutamide. The results show that the transcriptional regulation of prostatic secretory proteins differs greatly among lobes, generally being more tightly regulated in the VP. A number of growth factor mRNAs were differentially expressed in separate lobes and were regulated by testosterone in a lobe-specific manner. Lobe-specific regulation by androgen was also found for other genes, including the DAD-1 and calreticulin genes. Thus, hormone-dependent transcriptional regulation of prostate genes differs among lobes, and there is also interlobar diversity of basal mRNA expression levels.

Protein Profiling of Rat Ventral Prostate following Chronic Finasteride Administration

To better understand the effects of antiandrogens on the prostate, we investigated the changes in the proteome of rat ventral prostate (VP) following treatment with a well characterized 5alpha-reductase inhibitor, finasteride. Sprague-Dawley rats were treated daily by gavage with finasteride at 0, 1, 5, 25, and 125 mg/kg/day. Changes in plasma hormone levels as well as the weight and histology of sex accessory tissues were determined after 28 days of treatment and showed a dose-related decrease of VP weights together with a marked atrophy of the tissue visible at the macroscopic and microscopic levels. In addition, significant reductions in seminal vesicle and epididymis weights were noted. VP proteins were analyzed by two-dimensional gel electrophoresis: 37 proteins, mainly involved in protein synthesis, processing, and cellular trafficking and in metabolism, detoxification, and oxidative stress, were identified as modulated by finasteride. The prominent feature of this study is the demonstration of finasteride dose-dependent up-regulation of a protein similar to l-amino-acid oxidase 1 (Lao1). An up-regulation of this protein was also observed with the antiandrogen flutamide. Lao1 expression occurred as early as 48 h after antiandrogen administration and persisted throughout the treatment duration. Immunohistochemistry showed that this protein was only detectable in epithelial cells and secretory vesicles. Altogether these data point to a potential use of Lao1 to reveal antiandrogen-induced prostate injury.

Dosagem e correlação do antígeno prostático específico com as alterações histológicas dos anexos sexuais do hamster sírio

OBJETIVO: Verificar os níveis de PSA total no Hamster Sírio, Mesocricetus auratus, jovem e adulto e demonstrar possíveis correlações entre esses níveis com as alterações histológicas dos anexos sexuais: próstata, vesículas seminais e testículos. MÉTODO: Foram examinados dez (n=10) Hamsters jovens, com idade inferior a sete semanas de vida e vinte (n=20) Hamsters com idade superior a um ano. Fez-se a dosagem do PSA e estudo histológico dos anexos sexuais em ambos os grupos e procurou-se a correlação entre o PSA encontrado e as alterações histológicas. RESULTADOS: A média de idade para os animais jovens, (grupo controle), foi de 46,7 dias (Desvio-Padrão-DP=1,16). Nos animais adultos, (grupo experimental), a média de idade não foi determinada, embora todos apresentassem idade acima de um ano no momento da morte. A média do peso dos animais jovens quando foram mortos foi de 57kg e dos animais adultos 126,5g. O PSA foi dosado no plasma de todos os animais adultos e em sete dos animais jovens. Em três animais do grupo jovem o PSA não foi detectado. A média do PSA nos animais jovens foi de 0,252ng/mL (nanogramo por mililitro) e nos animais adultos de 0,325ng/mL. Os animais jovens não apresentaram alterações histológicas nos anexos sexuais examinados. Entre os Hamsters adultos, quatorze (70%) animais apresentaram alguma alteração nos anexos sexuais: dez (50%) apresentaram Hiperplasia Benigna da Próstata (HBP); um (5%) apresentou HBP, prostatite e inflamação das vesículas seminais; um (5%) inflamação supurativa das vesículas seminais; um (5%) apresentou infarto testicular e prostatite; um (5%) apresentou inflamação das vesículas seminais, sem HBP e prostatite. Não se detectou relação estatística entre os níveis de PSA e a ocorrência de HBP, embora os portadores da hiperplasia prostática exibissem médias de PSA bastante superiores às apresentadas pelos não portadores de hiperplasia. Não foram também determinadas relações estatísticas entre os níveis de PSA e as alterações das vesículas seminais e testículo. CONCLUSÕES: 1- O Hamster Sírio, Mesocricetus auratus, apresenta PSA sérico dosável e seu valor médio para o Hamster jovem é de 0,252ng/mL e no Hamster adulto é de 0,325ng/mL.2. Não foi possível correlacionar os níveis de PSA com as alterações histológicas encontradas nos anexos sexuais do Mesocricetus auratus.

Developmental stage-specific expression and tissue distribution of pierisin-1, a guanine-specific ADP-ribosylating toxin, in Pieris rapae

The cabbage butterfly (Pieris rapae) produces pierisin-1, an apoptosis-inducing protein against mammalian cells. In order to clarify the biological role of pierisin-1 in P. rapae, its expression during developmental stages was examined. Low levels of pierisin-1 mRNA and protein were detected in first-instar larvae. During growth until the fifth-instar larval stage, the amounts of the mRNA steadily increased to reach about 50-100 times the initial level. Then it rapidly decreased before pupation. The levels of mRNA in the pupae and the adults were as low as in the first-instar larvae. Levels of pierisin-1 protein also increased around 100 times from the first-instar to the fifth-instar larvae and then gradually decreased by over 90% during the pupal stage. Immunostaining of pierisin-1 demonstrated the protein to be mainly located in fat bodies of fifth-instar larvae and early-phase pupae. Although the staining intensity was low, fat bodies of early instars of the larvae and adults were also found to be positive. Moreover, examination of isolated fat body and other tissue samples of the insects were consistent with the above observations. Thus, the results indicate that mRNA of pierisin-1 was highly expressed in late stages of larvae, and that the protein accumulated in fat bodies where it persists during pupation.

Gene expression analysis in the ventral prostate of rats exposed to vinclozolin or procymidone

Vinclozolin and procymidone are antiandrogens that are thought to share a common androgen receptor (AR) mediated mechanism of action. This assessment is based primarily on morphological, AR binding, and in vitro transcriptional activation studies. Studies designed to evaluate the gene expression profiles induced by these compounds have the potential to provide further information to test this hypothesis. We have used targeted gene arrays to examine gene expression in the ventral prostate (VP) of 100-day old Sprague Dawley male rats exposed to either vinclozolin or procymidone. Animals were castrated and administered silastic implants with or without testosterone. A subset of testosterone treated animals was then dosed with 200 mg/kg of either fungicide in corn oil. Four treatment groups were used: castrated (C), testosterone (T), testosterone+vinclozolin (V), and testosterone+procymidone (P). Tissue from the VP was collected from six animals per group (3 animals per block x 2 blocks) at 20 h and at 4 days after the start of treatment. Total RNA was then isolated and gene expression analyzed using Clontech Atlas Rat 1.2 Toxicology arrays. When compared to group T, similar changes in gene expression were observed in groups C, P and V at both the 20 h and 4 day time points. After 20 h of treatment, 20 genes were similarly affected across these three treatment groups. Down-regulated genes included various molecular chaperones, the 11-kDa diazepam binding inhibitor, cyclin D1, and mitochondrial aspartate aminotransferase. Genes such as the androgen receptor, PTEN, and ERK2 were up-regulated. Three of the down-regulated genes, GRP78 (BiP), Dad1, and mitochondrial aspartate aminotransferase have been previously shown to be directly androgen regulated. Fifty-four genes were affected at 20 h, whereas, 311 genes were altered 4 days after the start of treatment. These observations, in part, may reflect regression of the VP at the later time point. These results support the hypothesis that procymidone and vinclozolin share a common mechanism or mode of action, a critical step in a cumulative risk assessment.

Estrogen enhancement of androgen-responsive gene expression in hormone-induced hyperplasia in the ventral prostate of F344 rats

It has been postulated that, in addition to the crucial role of androgens, estrogens may be involved in development of prostate hyperplasia and cancer. In rats, combined administration of estrogen and androgen synergistically increases ventral prostate weight, and continued treatment results in the development of glandular hyperplasia. Prostate adenocarcinoma can be induced by chemical carcinogens in rats, and estrogen given together with an androgen generally shortens the latent period or increases the incidence and/or multiplicity of carcinomas. However, the mechanisms responsible for these synergistic effects of estrogen and androgen are poorly understood. In the present study, we examined the combined effects of 17beta-estradiol (E2) and testosterone (T) on gene expression in an early stage of prostate hyperplasia in an F344 rat model. ERalpha expression, which has been suggested to contribute to development of prostatic hyperplasia, was increased by the combined treatment with T and E2, while it was suppressed by T alone. Expression levels of two androgen-responsive genes, probasin and kallikrein S3, were increased in the ventral prostate of rats treated with T plus E2 for 4 weeks in a dose-dependent manner, while short-term treatment did not alter the expression. These results suggested that enhancing effects of E2 on transcription of androgen-responsive genes, as well as an increased level of ERalpha may play roles in the synergistic effects of E2 on T-induced prostate hyperplasia.