Immunolocalization of estrogen receptor alpha and beta in human fetal prostate

PURPOSE: We examined the immunolocalization of estrogen receptor (ER)alpha and ERbeta in the human fetal prostate. MATERIALS AND METHODS: Tissue sections from human fetal prostates at 7 to 22 weeks of gestation were stained with antibodies to ERalpha, ERbeta, and cytokeratin 10 and 14. RESULTS: ERalpha expression was not detected until 15 weeks of gestation with sparse staining in the utricle. By 19 weeks increased ERalpha expression was seen in the luminal cells of the ventral urogenital epithelium (UGE), basal cells of the dorsal UGE, utricle, distal periurethral ducts, peripheral stroma and posterior prostatic duct. K14 was detected in basal cells of the UGE and in several posterior acini. At 22 weeks ERalpha expression was more intense in all of these areas. ERbeta was expressed throughout the UGE, ejaculatory ducts, müllerian ducts and entire stroma at 7 weeks. Intense ERbeta staining was observed in these areas and in the prostatic buds by 8 weeks with persistent intense staining through 22 weeks. CONCLUSIONS: To our knowledge we report the first immunolocalization of ERalpha in the human fetal prostate and the earliest demonstration of ERbeta expression in the prostate at 7 weeks of gestation. ERbeta expression is intense during ductal morphogenesis, suggesting a role in normal glandular growth and proliferation. The induction of squamous metaplasia in the UGE, distal periurethral ducts and utricle is associated with ERalpha expression in these areas, while the induction of squamous metaplasia in peripheral prostatic acini is associated with peripheral stromal ERalpha expression. This study suggests estrogen signaling pathways in the human fetal prostate via ERalpha that involve epithelial-epithelial and epithelial-stromal interactions.     

Prostate gland growth during development is stimulated in both male and female rat fetuses by intrauterine proximity to female fetuses

In rodents, steroid hormones are transported between adjacent fetuses, and male or female fetuses that develop in utero between female fetuses (2F males or 2F females) have higher serum levels of estradiol and lower serum levels of testosterone relative to siblings of the same sex that develop between two male fetuses (2M males or 2M females). The present study was prompted by the prior unexpected finding that as adults, 2F male mice have an enlarged prostate, and increased numbers of prostatic androgen receptors relative to 2M males. We examined prostate development in both male and female rat fetuses from different intrauterine positions using computer-assisted, 3-dimensional reconstruction of the urogenital complex. In males, this included the prostate, seminal vesicles and utricle (a remnant of the Müllerian ducts), while in females it included development of prostatic glandular buds. The mean cross-sectional area of developing prostatic epithelial buds, utricle and seminal vesicles was significantly increased in 2F male relative to 2M male fetuses. In female fetuses, prostatic bud development was significantly more likely to occur in 2F (67%) than in 2M (29%) animals. These findings suggest that the transport of a small supplement of estrogen from adjacent female fetuses enhances androgen-dependent accessory organ development. We also found that mRNAs encoding receptors for both estrogen and androgen were located in the mesenchyme of the developing male prostate. The localization of estrogen and androgen receptor mRNA in this region further suggests that the mesenchymal induction of prostatic epithelial growth involves both hormones. The cranial dorsolateral prostatic buds exhibited the greatest enlargement in 2F males. This region of the developing prostate in rats is comparable (that is the embryonic homologue) to the region exhibiting benign prostatic hyperplasia (BPH) during aging in men. We propose that the potential for pathological regrowth of the prostate during aging is imprinted by estradiol during fetal development.     

sonic hedgehog信号通路蛋白在人胚胎前列腺发育不同阶段的表达及意义

目的:探明son ic hedgehog信号通路中几个关键的效应蛋白son ic hedgehog(SHH)、Patched1(PTC1)、Smoothened(SMO)及GLI1在人胚胎前列腺组织中的定位表达及变化。方法:应用免疫组织化学方法研究SHH、PTC1、SMO及GLI1在不同胎龄(10~39周)人胚胎前列腺组织中的表达变化情况。结果:随胎龄增大,SHH、PTC1、SMO及GLI1在前列腺组织中的表达水平呈由弱变强,由强渐弱,又由弱转强的双峰变化趋势。SHH和SMO仅表达在胚胎前列腺上皮细胞中;而PTC1和GLI1主要表达在上皮细胞外,也可表达在腺体周围的间质中。结论:SHH信号通路参与了人胚胎前列腺发育的调控过程,可能对于腺体发育初期的诱导发生,以及后期的增殖、分化都具有重要的调控作用。     

The induction of new ductal growth in adult prostatic epithelium in response to an embryonic prostatic inductor

Tissue recombinants were prepared with a single epithelial ductal tip from adult prostate and mesenchyme from either the embryonic urogenital sinus or adult urinary bladder. Recombinants were grown in vivo beneath the renal capsule of male hosts. After 4 weeks of in vivo growth, extensive growth of arborizing ducts was apparent in recombinants composed of urogenital sinus mesenchyme and a single adult prostatic ductal tip. One-dimensional polyacrylamide gel electrophoresis indicated that these recombinants contained many of the proteins of the mature prostate. Heterospecific recombinants (rat urogenital sinus mesenchyme and mouse prostatic epithelium) showed the ductal tissue to be derived solely from the prostatic epithelium. In recombinants of a prostatic ductal tip with mesenchyme from the urinary bladder, ductal growth was absent, the ductal tip was maintained as a single, discrete, epithelial structure, and the protein composition of these recombinants more closely resembled that of the bladder. The results demonstrate that the epithelial cells of the adult prostate can participate in new ductal growth in response to an embryonic prostatic inductor. These data provide experimental evidence to support the hypothesis that human benign prostatic hyperplasia may result from the anomalous reactivation of embryonic growth potential in the adult prostate.     

Neuroendocrine cells during human prostate development: does neuroendocrine cell density remain constant during fetal as well as postnatal life?

BACKGROUND: Knowledge concerning differentiation of neuroendocrine (NE) cells during development of the human prostate is rather fragmentary. Using immunohistochemistry combined with a morphometric method, we investigated the distribution and density of NE cells in the developing human prostate, with special emphasis on the topographical relationship of NE cells with the developing gland. METHODS: Consecutive sections from a total of 42 human prostates taken during autopsy of fetuses (12-38 weeks of gestation), prepubertal males, and young adults were immunostained for chromogranin A and serotonin. Computer-assisted image analysis was used to assess the total number of cells in the different parts of the branching glandular anlage, i.e., budding tips and acini/ducts. Next, the number of NE cells was counted manually. The NE cell density (NE cell index) was then determined. RESULTS: NE cells could first be detected in the prostate from 13 weeks of gestation. By 21 weeks of gestation, all prostates contained NE cells. NE cells were mainly confined to the acinous/ductal regions, while most of the budding tips lacked NE staining. NE cell indexes of individuals were highly variable, mostly in the youngest age group. CONCLUSIONS: In the normal prostate, NE cell density probably remains constant in acini/ducts from fetuses to young adulthood. The presence of neuroendocrine cells in well-developed glandular structures at such an early fetal age and their absence in the less differentiated budding tips possibly indicates that differentiation of NE cells is associated with glandular maturation. NE cells occur preferentially in the acinous/ductal region, implying a paracrine function during secretory differentiation of exocrine epithelial cells.     

Prostatic development, cytodifferentiation and growth: epithelial-mesenchymal interaction and heterogeneity of prostatic cellular activity

Prostatic growth and hormonal effects on the prostate play a basic role in the pathogenesis of abnormal proliferative diseases (i.e. benign prostatic hyperplasia and prostatic carcinoma). During the embryonic period, the prostate is organized through the budding and branching of the epithelial cords into the urogenital sinus mesenchyme. The urogenital sinus mesenchyme has an inductive potential for the prostatic epithelial development and cytodifferentiation under the influence of androgen and an epithelial-mesenchymal interaction. In this interaction, mesenchymal cells are considered as a mediator of hormonal action on epithelial cells. Postnatal prostatic growth is obtained further ductal branching morphogenesis and regulated by the epithelial-mesenchymal interaction, androgen, and epithelial/mesenchymal ratio. Castration-induced degeneration, and androgen-induced regeneration of the glandular architecture of the mouse prostate were investigated by microdissection techniques that permitted precise quantitation of the numbers of the terminal ductal tips and ductal branch-points. During the first 15 days after birth, active branching morphogenesis occurred as a result of focally high levels of DNA synthesis confined almost exclusively to the distal tips of the branching ducts. Following castration about 35% of the ductal tips and branch-points were lost in distal regions (usually near the capsule). By contrast, in more proximal regions of the prostate the ducts survived in an atrophic condition. The lost distal ductal morphology completely regenerated following administration of testosterone propionate (TP) to the castrated males. Whole-mount autoradiography demonstrated that labelling intensity reached a maximum on the third day of TP treatment in distal ductal areas. Recognition of the mesenchymal-epithelial interaction and heterogeneities in the morphogenesis, androgen dependency, and DNA synthetic activity within the prostatic architecture is fundamental to understanding the mechanism of androgenic regulation of normal or abnormal prostatic growth and development.     

Immunohistochemical antibody cocktail staining (p63/HMWCK/AMACR) of ductal adenocarcinoma and Gleason pattern 4 cribriform and noncribriform acinar adenocarcinomas of the prostate

Overexpression of alpha-methylacyl coenzyme A racemase (AMACR) in combination with absence of basal cell markers [ie, p63 and high molecular weight cytokeratin (HMWCK)] is typical of classic acinar prostatic adenocarcinoma. We studied the expression and diagnostic utility of p63/HMWCK/AMACR immunohistochemical cocktail staining in ductal adenocarcinoma and cribriform Gleason pattern 4 acinar prostate cancer and compared it to noncribriform Gleason pattern 4 acinar prostate cancer. One to 4 representative formalin-fixed paraffin-embedded archival tissue blocks from 62 radical prostatectomy specimens harboring prostate cancer of ductal (n=51), cribriform Gleason pattern 4 acinar (n=27), and noncribriform Gleason pattern 4 acinar adenocarcinoma (n=48) were included in this study. Immunohistochemistry was performed using a triple stain of AMACR, p63, and HMWCK. Only staining that was moderate or strong was considered positive. The percentage of staining intensity and the presence of occasional basal cells positive with p63/HMWCK were recorded in each histologic type of prostatic adenocarcinoma. Seventy-seven percent of ductal prostatic adenocarcinoma, 67% of cribriform acinar prostatic carcinoma, and 81% of noncribriform acinar prostatic carcinoma showed positive staining for AMACR. There was no statistically significant difference between AMACR staining among the 3 histologic types, although there was a trend for noncribriform acinar prostatic carcinoma to have greater expression of AMACR than cribriform acinar prostatic carcinoma (P=0.07). Staining was often heterogeneous, varying in staining intensities within the same histologic type of carcinoma. Basal cells were detectable by p63 and HMWCK in a patchy fashion in 31.4% (16/51) of ductal and 29.6% (8/27) of cribriform acinar carcinomas compared with 2.1% (1/48) of noncribriform acinar carcinomas. In summary: (1) the majority of prostatic ductal and cribriform acinar carcinomas strongly expressed AMACR, however, subpopulations of these prostatic carcinoma were either completely negative or only weakly positive; (2) AMACR staining was often heterogeneous in intensity in the same histologic type of tumor, even within the same case; (3) patchy basal cell staining in noncribriform acinar prostatic carcinoma is rare. In contrast, remnants of basal cells identified by p63/HMWCK were seen in a patchy fashion in a significant minority of both ductal and cribriform acinar prostatic adenocarcinoma, which most likely represents intraductal spread of tumor.     

Morphologic and biochemical alterations in rat prostatic tumors induced by fetal urogenital sinus mesenchyme

Because fetal urogenital sinus mesenchyme (UGM) has been found to be highly inductive when recombined with normal adult prostate tissues or normal and neoplastic bladder epithelium, we investigated whether fetal UGM also interacts with established hormone-responsive and unresponsive rat Dunning and Nb prostate tumors. Our results indicate that: 1) fetal UGM acts directly on selected rat prostatic tumors by inducing histomorphologic changes (e.g., inducing acinar ductal structures and secretory activity) in the tumors toward more differentiated forms resembling that of the adult prostate gland; 2) fetal UGM either increased the growth rate of or maintained the sizes of three of the four interacting rat prostatic tumors; and 3) fetal UGM markedly reduced the lactate dehydrogenase activity of Nb-autonomous tumor toward a level comparable to that of the normal rat prostate gland. Our data suggest that fetal UGM can directly affect the growth and differentiative functions of selected rat prostatic tumors.     

Neurogenic origin of human prostate endocrine cells

OBJECTIVES: To determine the histogenetic origin of prostate neuroendocrine cells in human embryos. METHODS: Prostatic tissue in human fetuses, ranging in gestational age from early week 10 to term, and infantile and pubertal glands were studied immunohistochemically. The distribution of neuroendocrine cells within the developing gland was semiquantitatively determined. Antibodies against the neuroendocrine markers chromogranin A (CgA) and protein gene product 9.5 (PGP), along with markers of prostatic secretion (prostate-specific antigen [PSA], prostatic acid phosphatase [PAP]), were used. They were applied either individually or in double-labeling experiments, as well as in experiments combining CgA immunohistochemical analysis with in situ hybridization or in situ end-labeling. RESULTS: In embryos of less than 65-mm crown-rump length (CRL) (ie, younger than 12 weeks of gestation), the epithelium of the urogenital sinus was free of endocrine cells. On either side of the future prostatic mesenchyme, paraganglia containing CgA-immunoreactive cells are present, which start to penetrate the urogenital mesenchyme. In the late 10th week, these CgA-immunoreactive cells are found dispersed in the urogenital mesenchyme. In embryos of 65-mm CRL, when prostatic anlagen start to sprout from the urogenital epithelium, very few (but typically shaped) neuroendocrine cells appear in the urogenital sinus epithelium. Later, after the 12th week, when solid prostatic ducts have started forming, CgA-immunoreactive neuroendocrine cells are also present in these buds. The number of neuroendocrine cells in the urethral epithelium is considerably increased, and with the continuous sprouting and lumen formation of prostatic anlagen, neuroendocrine cells are transported into the future gland. Neuroendocrine cells observed in stroma of prenatal and postnatal prostates may also contribute to the neuroendocrine cell population of the gland. CONCLUSIONS: Our results provide the first evidence that human prostate neuroendocrine cells represent a cell lineage of their own, being of neurogenic origin and therefore distinct from the urogenital sinus-derived prostate secretory and basal cells.     

Semiquantitative morphology of human prostatic development and regional distribution of prostatic neuroendocrine cells

BACKGROUND: The neuroendocrine cells of the human prostate have been related to proliferative disorders such as prostatic cancer. Their origin, distribution, and development have therefore been studied and discussed in terms of current stem cell concepts in the prostate. METHODS: Prostatic tissue specimens (n = 20) from human fetuses (n = 8), prepubertal and pubertal children (n = 8) and mature men (n = 4) were studied immunohistochemically using antibodies directed against neuroendocrine, epithelial as well as secretory markers. Semiquantitative computer-assisted evaluation of different epithelial and stromal components based on stereological principles was performed on azan-stained sections representative of all developmental stages. RESULTS: By the end of gestational Week 9, neuroendocrine (NE) cells appear in the epithelium of the urogenital sinus and are subsequently closely associated with the formation of urethral prostatic buds. The fetal and postnatal distribution pattern of NE cells within the gland is characterized by a relatively constant number of cells per gland similar to prostatic smooth muscle cells. Likewise, a density gradient exists with the highest density in the large collicular ducts and almost no NE cells in subcapsular peripheral acini. In peripheral ducts, the distribution is random. Maturation of the NE cells precedes that of the secretory cells by about 10-16 years. CONCLUSIONS: A second prostatic stem cell lineage, different from the urogenital sinus (UGS)-lineage is hypothesized originating from immature neuroendocrine cells. Being morphologically indistinguishable from the UGS-derived prostatic secretory cell lineage, it gives rise to neuroendocrine cells. Their presence is apparently important for proliferation regulation of the UGS-derived lineage of the prostate.     

波形蛋白、细胞角蛋白5,18,19在人胚胎前列腺发育不同阶段的表达及意义

目的 探讨波形蛋白（Vimentin），细胞角蛋白（Cytokeratin）5、18、19（CK5、18、19）在人胚胎前列腺发育不同阶段组织及细胞中的定位表达变化及其在前列腺胚胎发育中的意义。方法 应用免疫组织化学方法研究Vimentin、CK5、CK18、CK19在不同胎龄前列腺组织中的表达变化。结果 胚胎前列腺上皮细胞中波形蛋白随胎龄增大其表达呈由弱到强，又由强减弱的变化趋势；CK5和CK18的表达起初分布无规律，但是随胎龄增大，CK5和CK18逐渐分别定位表达于基底细胞层和管腔上皮细胞层；CK19则在基底细胞层和管腔上皮细胞层中均有表达，且强度较一致，基本不随胎龄增大而变化。结论 胚胎前列腺上皮细胞Vimentin的表达，可能有助于上皮细胞的游走迁移，以形成早期原始腺体。CK5、CK18以及CK19阳性细胞在原始腺体中的动态分布与胚胎前列腺上皮细胞的分化状态有关。     

Hedgehog signaling in prostate growth and benign prostate hyperplasia

Hedgehog (Hh) signaling has long been recognized for its role in axial patterning, mesenchymal-epithelial inductive signaling, and growth regulation during fetal development. In many embryonic tissues, Hh functions as a proliferative stimulus. Sonic hedgehog and Indian hedgehog are both expressed by the urothelium of the fetal prostate anlage, where they regulate cell proliferation and differentiation and play a role in prostate ductal budding. Whereas Hh signaling in mouse prostate diminishes during adolescence and is maintained at a low level in the adult, robust Hh signaling is commonly found in the adult human prostate. The reason(s) for robust Hh signaling in the adult human prostate and the actions of Hh signaling on growth and differentiation in the adult are not well understood. However, increased Hh signaling has been associated with prostate cancer and has been shown to accelerate prostate cancer growth. These observations suggest that inappropriate reawakening of this developmental growth signal may play a pivotal role in prostate neoplasia. This review examines the role of Hh signaling during early prostate growth and in its corollary actions during prostate disease, including benign prostate hyperplasia and prostate cancer. The use of Hh inhibitors as a therapeutic modality for androgen-independent treatment of prostate disease is also discussed.     

Prostatic ductal adenocarcinoma showing Bcl-2 expression

Prostatic ductal adenocarcinoma represents a rare histological variant of prostatic carcinoma with features of a papillary lesion at cystoscopy. There are conflicts regarding the existence, origin, staging, grading, treatment and clinical behavior of this tumor. The aim of the present study is to examine the expression of Bcl-2 and p53 in prostatic ductal adenocarcinoma and to evaluate its origin by analyzing prostate specific antigen, prostate specific acid phosphatase, cytokeratins, epithelial membrane antigen and carcinoembryonic antigen expressions. The results confirmed the expression of prostate specific antigen and prostate specific acid phosphatase in prostatic ductal adenocarcinoma. The demonstrated expression of Bcl-2 was predominant in the better-differentiated tumor. Bcl-2 expression appears not to be associated with neuroendocrine differentiation as assessed by chromogranin A reactivity. Thus, the first case of a prostatic ductal adenocarcinoma showing Bcl-2 expression is presented. The tumor was negative for p53.     

四黄前列片对尿生殖窦植入法小鼠前列腺增生模型的影响

目的 探讨阴黄前列片对小鼠前列腺增生模型的影响。方法 选用NIH系雄性小鼠，依文献方法，行前列腺腹叶内植入尿生殖实组织，制备BPH动物模型，给药30d后处死动物，取前列腺组织，称重测量体积，组织切片观察前列腺腺腔嘶积和腺上皮高度，用免疫组化法研究实验各组前列腺组织中PCNA抗原和Caspase-3蛋白的表达。结果 四黄前列片可缩小前列腺体积，降低腺腔的面积和腺上皮高度，并能抑制前列腺组织中PCNA的表达，增加Caspase-3的表达。结论 四黄前列片能抑制模型小鼠前列腺增生，其机理可能与抑制前列腺细胞的增殖和诱导凋亡有关。     

2,3,7,8-tetrachlorodibenzo-p-dioxin inhibits prostatic epithelial bud formation by acting directly on the urogenital sinus

PURPOSE: In utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure causes lobe specific inhibition of prostate development in C57BL/6 mice due primarily to region specific inhibition of prostatic epithelial bud formation by the urogenital sinus (UGS). This inhibition requires that the receptor for TCDD, the aryl hydrocarbon receptor (AhR), must be present. We tested the hypothesis that TCDD inhibits prostatic epithelial bud formation by acting directly on the UGS. MATERIALS AND METHODS: UGSs were removed from WT and AhR null mutant (AhRKO) male C57BL/6 mice on gestation day 14 and incubated in vitro with vehicle, 10-8 M testosterone or 10-8 M testosterone plus 10-9 M TCDD for 5 days. Budding was evaluated by a newly developed technique, namely scanning electron microscopy of UGS epithelium after removal of UGS mesenchyme. RESULTS: Few buds were present in UGSs of either genotype in the absence of testosterone, while many were observed when testosterone was present. TCDD prevented prostatic epithelial buds from forming in UGSs from WT mice but it had no effect on UGSs from AhRKO mice. CONCLUSIONS: TCDD can act directly on the UGS to cause AhR dependent inhibition of prostatic epithelial bud formation. Because this inhibition occurred at a TCDD concentration similar to the estimated concentration at which TCDD inhibits bud formation in vivo, it appears that TCDD inhibits prostatic budding primarily via direct effects on the UGS rather than indirectly through effects on other organs.