bFGF和TGF-β1对原代培养的前列腺间质细胞的作用

目的:探讨碱性成纤维细胞生长因子(bFGF)和转化生长因子β1(TGF-β1)在良性前列腺增生(BPH)中的作用。方法:培养了人BPH间质细胞,采用MTT法检测无血清培养的间质细胞的增殖,用免疫组化方法检测平滑肌细胞表型变化,观察不同浓度bFGF和TGF-β1对培养的人BPH间质细胞的影响。结果:bFGF促进间质细胞增殖(P<0.05、P<0.01),较高浓度时(10μg/L)降低平滑肌细胞表型表达;TGF-β1(>0.1μg/L)抑制间质细胞增殖并增加平滑肌细胞表型表达(P<0.05、P<0.01);5μg/L的bFGF与0.001μg/L和0.01μg/L TGF-β1作用间质细胞,促进细胞增殖(P<0.01),与0.1μg/L,1μg/L及10μg/L TGF-β1作用间质细胞,抑制细胞增殖,0.1μg/L时对细胞的抑制作用轻微(P>0.05),1μg/L及10μg/L时出现明显的抑制(P<0.01),同时TGF-β1在较高浓度时(>1μg/L),平滑肌细胞表型表达明显增加(P<0.01)。结论:bFGF以时间和浓度依赖的方式促进培养的增生前列腺间质细胞的增殖,并减少平滑肌细胞表型表达;TGF-β1抑制间质细胞的生长并诱导间质细胞向平滑肌细胞分化,两者共同在BPH的形成机制中发挥着重要作用。     

Stromal cells of the human prostate: Initial isolation and characterization

The present study was conducted to isolate and to characterize stromal cells from the human prostate and to study the effects of androgen and different growth factors in this model system. Benign prostatic hyperplasia (BPH) tissue samples were obtained from transurethral resection of the prostate (TURP). Tissue specimens were mechanically and enzymatically dissociated by treatment with DNAse and collagenase. Epithelial cells were separated from stromal cells by discontinuous Percoll gradient centrifugation. The stromal cells obtained were cultured in phenol red-free RPMI-1640 supplemented with 10% fetal bovine serum. Immunocytochemical analysis revealed that the stromal cell cultures were composed of both smooth muscle cells and fibroblasts. The short and broad, smooth muscle cells were identified by using an antibody directed against α-smooth muscle actin. The thin and elongated fibroblasts stained positively for prolyl 4-hydroxylase. Smooth muscle cells were the predominant cell type in the present investigation. Typical cultures contained up to 99% of cells staining positively for α-smooth muscle actin. The prostate smooth muscle cultures were treated with dihydrotestosterone (DHT), bovine pituitary extract (BPE), basic fibroblast growth factor (bFGF) and transforming growth factor-β (TGF-β). When cells were cultured in serum free RPMI-1640 supplemented with ITS+ (insulin, transferrin, and selenious acid) no significant (P > 0.05) stimulative effect after treatment with DHT or TGF-β was detectable. Basic FGF had a slight but significant (P < 0.05) mitogenic effect in medium supplemented with ITS+. In the presence of 10% charcoal-stripped fetal bovine serum (cFBS) DHT, at a concentration of 0.1 nM, was able to cause a slight but significant (P < 0.05) mitogenic effect on BPH smooth muscle cells growth. Basic FGF was able to stimulate BPH smooth muscle cells in a concentration-dependent fashion. The combination of DHT and 0.1 ng/ml bFGF was able to increase the proliferation of prostate smooth muscle cells above either agents alone. Addition of BPE to serum free RPMI-1640 caused a significant (P < 0.05) stimulation of cell proliferation in a concentration-dependent fashion. Addition of TGF-β to serum or BPE containing RPMI-1640 caused a significant (P < 0.05) inhibition of cell proliferation in a concentration-dependent fashion. TGF-β was cytostatic to the benign prostatic smooth muscle cells only in the presence of media containing growth stimulating factors found in charcoal-stripped serum or in bovine pituitary extract. These results demonstrated that stromal fraction isolated from BPH specimens was composed of both fibroblasts and smooth muscle cells. These cells could be cultured and were able to respond to various growth stimulatory and inhibitory agents. © 1996 Wiley-Liss, Inc.     

Serum-free coculture of stromal and epithelial cells from benign prostatic hyperplasia with keratinocyte growth factor

We developed a serum-free coculture model of benign prostatic hyperplasia (BPH) to clarify whether stromal cells stimulate growth of epithelial cells from BPH tissues. Epithelial and stromal cells from freshly isolated BPH tissue were cultured separately in defined serum-free WAJC 404/RPMI 1640 medium supplemented with insulin, transferrin, selenium, hydrocortisone, bovine serum albumin, epidermal growth factor, basic fibroblast growth factor and keratinocyte growth factor. (3)H-Tdr incorporation into epithelial cells and stromal cells was used as a measure of proliferation. When epithelial cells were cocultured with stromal cells, (3)H-Tdr incorporation into epithelial cells was increased in comparison to that in epithelial cells cultured alone. Dihydrotestosterone significantly increased this effect. It is likely that the in vitro coculture model reported here will be useful for isolating and understanding stromal cell-derived paracrine growth factor(s).     

Effects of cyclic stretch on prostatic cells in culture

PURPOSE: The fundamental process in the development of benign prostatic hyperplasia (BPH) is a loss of homeostasis between cell proliferation and apoptosis. Prostatic smooth muscle cells contract under adrenergic control. The response of a cell to stretch may have a role in the pathogenesis of BPH. MATERIALS AND METHODS: Monolayer cultures of human prostatic stromal and epithelial cell lines were exposed to cyclic stretch for 48 hours. RESULTS: Cyclic stretch conferred resistance to etoposide induced apoptosis. Underlying this apoptotic resistance was increased expression of the anti-apoptotic Bcl-2 family of proteins. As measured by thymidine incorporation, the rate of proliferation also increased in benign epithelial cells under cyclic stretch conditions. Furthermore, an increase in the production of platelet-derived growth factor by stromal cells and transforming growth factor-beta by epithelial cells occurred under such conditions. CONCLUSIONS: The observed changes in proliferation and apoptosis may contribute to the understanding of BPH, ultimately leading to therapeutic and preventive applications.     

Interleukin-8 expression is increased in senescent prostatic epithelial cells and promotes the development of benign prostatic hyperplasia

BACKGROUND: Benign prostatic hyperplasia (BPH) is an extremely common disease of older men characterized by increased growth of prostatic epithelial and stromal cells. Previously we showed that senescent epithelial cells accumulate in the prostate of aging men and secrete interleukin-1 alpha (IL-1 alpha). IL-8 is also present at increased levels in BPH tissues and induces expression of FGF2, a potent stromal growth factor. Therefore, we sought to determine if IL-8 is also expressed at increased levels by senescent epithelial cells and if this secreted IL-8 plays a role in the pathogenesis of BPH. METHODS: Expression of IL-8 in human BPH tissue and primary cultures of prostatic epithelial cells was analyzed using an enzyme-linked immunoabsorption assay (ELISA). Tissue senescence was assessed by a quantitative assay for senescence-associated beta galactosidase (SA-beta gal). Proliferation of primary and immortalized prostatic epithelial cells in response to IL-8 was determined by counting of cells at intervals after addition of IL-8. RESULTS: Expression of IL-8 is significantly increased in vitro when cultured prostatic epithelial cells undergo senescence. Quantitative assay of BPH tissue extracts revealed that tissue IL-8 levels are correlated with both SA-beta gal activity and prostate weight. IL-8 promotes proliferation of primary and immortalized prostatic epithelial cells in culture. CONCLUSIONS: Senescence of prostatic epithelial cells results in increased expression of IL-8, which can promote proliferation of non-senescent epithelial and stromal cells by direct and indirect mechanisms, and in this manner contributes to the increased tissue growth seen in BPH.     

Cell lineage characteristics of human prostatic stromal cells cultured in vitro

BACKGROUND: An in vitro model of prostatic stromal cells suitable for experimental studies of the pathogenesis of BPH is still lacking. We therefore standardized the isolation, cultivation, and characterization of human prostatic stromal cell lineages. METHODS: Stromal cells were isolated from a surgical specimen of BPH. Using antibodies specific for either epithelial or stromal cells of the human prostate, the isolated cells were morphologically and immunohistochemically characterized. Viability and functional activity were assessed by proliferation assays and stimulation experiments. Gene expression was monitored by RT-PCR. RESULTS: In early passages (P8), cells showed a high purity (>/=98%) for stromal markers; about 60% displayed the characteristics of fibroblasts, and the remaining 40% were classified as smooth muscle cells. In late passages (P20), the proportion of muscle cells declined to 10%. Stimulation experiments including basic fibroblast growth factor (bFGF) resulted in enhanced proliferation, whereas dihydrotestosterone (DHT), estrogen, and flutamide did not influence proliferation. Gene expression studies demonstrated a positive signal for androgen receptor and keratinocyte growth factor (KGF). CONCLUSIONS: Prostatic stromal cells can be propagated several times and show karyotypic stability for up to 18 subculture experiments. The ratio of myoid and fibroblastic cells can be used for standardization of cell cultures with stable characteristics.     

Stimulative Effect of Transforming Growth Factor-β on Collagen Synthesis by Human Prostatic Stromal Cells In Vitro

Background :
Expression of transforming growth factor-β (TGF-β) in the prostate has been reported. The purpose of this study was to evaluate the effect of TGF-β on collagen synthesis by stromal cells isolated from a patient with benign prostatic hyperplasia (BPH).
Methods :
Human prostatic stromal cells (HPSC) derived from BPH tissue were cultured in serum-free medium. After incubation with TGF-β1, the concentration of procollagen type I C-peptide (PIP) in the HPSC-conditioned medium was measured by enzyme immunoassay while the concentration of procollagen type III N-peptide (PIIIP) was measured by radioimmunoassay. Per-cell production of each type of collagen was calculated by multiplying the measured concentration by the volume of medium and dividing by the number of harvested cells.
Results :
One ng/mL of TGF-β1 significantly ( P< 0.05) increased collagen production by HPSC, to 220% and 120% of control for types I and III, respectively. Increasing the amount of TGF-β1 to 10 ng/mL had no further effect. TGF-β1 did not significantly affect HPSC number at concentrations of either 1 or 10 ng/mL. There was a strong correlation between PIP and PIIIP production (r= 0.929, P< 0.001).
Conclusion :
These findings suggest that TGF-β stimulates accumulation of extracellular matrix in stromal BPH tissue without affecting proliferation of stromal cells.     

Heat-induced apoptosis in human prostatic stromal cells

OBJECTIVE: To determine whether heat, used in transurethral microwave thermotherapy (TUMT) for benign prostatic hyperplasia and which causes necrotic lesions within the adenoma, induces apoptosis in benign human prostatic stromal cells. Materials and methods Prostatic stromal cells were cultured from benign human prostatic tissue. The origin of the cells was identified by immunohistochemical staining and transmission electron microscopy. Cell cultures were exposed to moderate hyperthermia (47 degrees C) for 1 h and any apoptosis detected by light microscopy, transmission electron microscopy and the measurement of induced caspase-3-like activity. RESULTS: The cultures contained a mixed population of smooth muscle cells and myofibroblasts. Twenty-four hours after heat exposure, 76% of the cells were apoptotic and the caspase activity had increased, whereas only 14% of the cells were necrotic. CONCLUSION: Moderate hyperthermia induces apoptosis in cultured human prostatic stromal cells.     

Cellular senescence in the pathogenesis of benign prostatic hyperplasia

BACKGROUND: Senescent cells accumulate in tissues with age and show changes in protein expression that may influence the function of adjacent cells and contribute to the development of tissue pathologies associated with aging. Benign prostatic hyperplasia (BPH) is an extremely common disease of older men characterized by increased growth of prostatic epithelial and stromal cells. In BPH, there is an increased expression of Il-1alpha by prostatic epithelial cells that results in elevated expression of FGF7 by stromal cells, which in turn is strongly correlated with epithelial proliferation. METHODS: Human BPH tissue and primary cultures of prostatic epithelial cells were analyzed by histochemical and quantitative assays for senescence-associated beta galactosidase (SA-beta gal). Il-1alpha expression was localized by immunohistochemistry and Il-1alpha tissue content determined by enzyme-linked immunoabsorption assay. RESULTS: Expression of Il-1alpha is significantly increased in vitro when cultured prostatic epithelial cells undergo senescence. In BPH tissue a substantial population of epithelial cells express senescence-associated beta galactosidase (SA-beta gal), a marker of cellular senescence. By quantitative assay, SA-beta gal activity is correlated with both tissue levels of Il-1alpha and the severity of BPH. CONCLUSIONS: One mechanism driving BPH in older men is the accumulation of senescent epithelial cells expressing Il-1alpha, which in turn increases FGF7 secretion and proliferation of non-senescent epithelial cells. Thus there is a mechanistic linkage between cellular senescence and one of the most common pathologies of older men.     

Protease-activated receptor-1 upregulates fibroblast growth factor 7 in stroma of benign prostatic hyperplasia

BACKGROUND: Benign prostatic hyperplasia (BPH) is characterized by abnormal epithelial and stromal proliferation causing urinary obstruction. Prostate growth is regulated by a variety of growth factors secreted from the stroma, including fibroblast growth factor 7 (FGF-7), a potent epithelial-specific growth factor which is increased in hyperplastic prostate. However, the mediator(s) of FGF-7 over-expression is unclear. Protease-activated receptor-1 (PAR-1) is a G-protein coupled receptor known to induce multiple biological processes, but its effect on BPH pathogenesis is mostly unknown. The aim of this study was to investigate the role of PAR-1 as a mediator of BPH development. METHODS: PAR-1 expression was investigated in BPH and normal prostate tissues by immunohistochemistry. Prostate stromal cells were isolated from BPH specimens, cultured and immunohistochemically characterized. Cultured stromal cells were stimulated with PAR-1 agonists, and extracellular-signal regulated kinase (ERK1/2) activation and cell proliferation were examined. PAR-1 mediated FGF-7 production by cultured stromal cells was assessed by RT-PCR and immunoassays, and verified by small interfering RNA (siRNA). RESULTS: PAR-1 expression was increased in BPH stroma. In stromal cells isolated from BPH tissues, PAR-1 agonists activated ERK1/2 in a time- and concentration-dependent manner and with resultant enhanced cell proliferation. Pertussis toxin-sensitive G protein/(betagamma-subunits)-phosphatidylinositol 3-kinase and protein kinase C pathways were involved in ERK1/2 phosphorylation. PAR-1 activation strikingly induced FGF-7 production from cultured stromal cells mediated predominantly via ERK1/2 signaling pathway, and PAR-1 siRNA decreased the elicited FGF-7 upregulation. CONCLUSIONS: The expression and function of PAR-1 in BPH stroma indicate PAR-1 may play important roles in BPH pathogenesis.     

癃必消胶囊对体外培养的人前列腺增生间质细胞TGF-β1和Smoothelin基因表达的影响

目的:研究中药癃必消胶囊对体外培养的人前列腺增生间质细胞TGF-β1和Smoothelin基因表达的影响。方法:把含癃必消胶囊的药物血清加入到体外培养的人前列腺增生间质细胞中,采用实时定量RT-PCR检测TGF-β1和Smoothelin在体外培养的人前列腺增生间质细胞中的表达。结果:高、低中药浓度血清对TGF-β1的相对表达CT值分别为0.158±0.020、0.169±0.020,较对照组显著降低(P<0.01);高、低中药浓度血清对Smoothelin的相对表达值分别为0.035±0.007、0.036±0.007,较对照组显著降低(P<0.01)。结论:癃必消胶囊可能通过抑制前列腺间质细胞TGF-β1和Smoothelin基因的表达达到治疗前列腺增生的目的。     

Experimental cryptorchidism inhibited growth of the rat ventral prostate

Adult Sprague-Dawley male rats, weighing about 350 g, were rendered cryptorchid by suturing the testes to the lateral abdominal wall. Twenty-eight days later, cryptorchidism resulted in a significant decline in testis weight and suppressed spermatogenesis. The ventral prostate was significantly smaller in cryptorchid rats. There was no significant difference in serum testosterone levels between the normal and cryptorchid rats. Charcoal-stripped aqueous extracts of the testis from intact and cryptorchid animals were tested on primary cultures of rat prostatic stromal cells. Cultures treated with extract from the intact testis had a significantly increased cell proliferation as assessed by cell count and by the rate of 3H-thymidine incorporation. Additionally, extracts of seminiferous tubules significantly increased prostate stromal cell proliferation compared to extracts of testicular interstitial components. Furthermore, this proliferative effect of testicular extracts is specific to the prostate as extract of both normal and cryptorchid testis stimulated proliferation of rat footsole fibroblasts in culture, but only extracts from intact testis stimulated proliferation of prostate stromal cells. These observations demonstrate that the testis produces nonandrogenic substances that can promote growth of prostatic stromal cells and that these substances were eliminated in the cryptorchid testis.     

Pre-clinical evidence for the use of phosphodiesterase-5 inhibitors for treating benign prostatic hyperplasia and lower urinary tract symptoms

OBJECTIVE: To evaluate the potential of sildenafil, vardenafil and tadalafil, all phosphodiesterase-5 (PDE-5) inhibitors used for treating erectile dysfunction, for treating benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). MATERIALS AND METHODS: The mRNA expression of the PDE-5 was determined in rat LUT tissues. The PDE-5 inhibitors were also tested in organ-bath experiments and in a partial bladder outlet obstruction (BOO) rat model in vivo. RESULTS: The highest PDE-5 mRNA expression was in the bladder, followed by the urethra and prostate. PDE-5 inhibitors dose-dependently reduced the contraction of the isolated bladder, urethral and prostate strips. The rank order of potency was vardenafil > sildenafil > tadalafil. In human prostate stromal cells vardenafil inhibited cell proliferation and was more effective than tadalafil and sildenafil. In the BOO model, there was a reduction in the non-voiding contractions after bolus intravenous administration of 3 mg/kg sildenafil and vardenafil. CONCLUSION: These results show that PDE-5 is expressed in LUT tissues. PDE-5 inhibitors induced significant relaxation of these tissues, inhibited the proliferation of human prostate stromal cells and reduced the irritative symptoms of BPH/LUTS in vivo. Therefore, PDE-5 inhibitors could be used as an effective treatment for BPH/LUTS.     

In vitro culture of human prostatic tissue

Summary A procedure is described which yields a significant percentage of long-term mixed cell cultures of human prostatic tissue. Attempts were made to suppress the proliferation of stromal fibroblasts and to characterize the cultured cells as those of prostatic origin. The problems associated with establishing epithelial cell lines are discussed.     

The surface character of separated prostatic cells and cultured fibroblasts of prostatic tissue as determined by concanavalin-A hemadsorption

Con-A-coated human type O red blood cells (indicator RBC) were used for ConA reactivity assay of separated epithelial cells and cultured fibroblasts of human prostatic tissue. The epithelial cells of carcinoma showed higher reactivity than those of normal tissue or hyperplastic tissue. Although both cultured fibroblasts of PC and BPH are considered to be non-malignant, it is clearly demonstrated that the PC fibroblasts have a malignant surface character in terms of ConA reactivity, whereas the BPH fibroblasts have a quite low ConA reactivity. ConA-mediated HAD appeared to be a useful tool to distinguish malignant epithelial cells of human prostate from non-malignant ones. It still remains unknown whether the alteration of PC fibroblasts is the cause or the result of carcinogenic transformation of prostatic tissue.     

FGF7 and FGF2 are increased in benign prostatic hyperplasia and are associated with increased proliferation.

PURPOSE: To determine if overexpression of FGF7 and FGF2 occurs in benign prostatic hyperplasia (BPH) and if so, whether such overexpression is correlated with increased proliferation of epithelial and/or stromal cells. MATERIALS AND METHODS: The FGF7 and FGF2 content of protein extracts of normal peripheral zone, normal transition zone and hyperplastic prostatic tissues were determined by enzyme-linked immunoabsorption assay. Proliferation of epithelial and stromal cells was assessed by immunohistochemistry with anti-Ki67 antibodies on frozen sections of the same tissues used for protein extraction. The in vitro effects of FGF7 and FGF2 on proliferation were assessed by addition of recombinant growth factor to primary cultures of prostatic epithelial and stromal cells. RESULTS: We have found that both FGF7 and FGF2 are overexpressed in hyperplastic prostate in comparison to normal peripheral and transition zone tissue. FGF7 is a potent mitogen for epithelial cells in culture. Consistent with these in vitro effects, quantitative analysis of cellular proliferation by Ki67 immunohistochemistry revealed a strong correlation of epithelial proliferation with FGF7 content in BPH tissue, consistent with a key role for this growth factor in driving the abnormal epithelial proliferation in BPH. FGF2 is mitogenic for stromal cells in culture and there was a weaker correlation of FGF2 content with increased stromal proliferation. CONCLUSION: Overexpression of FGF7 and FGF2 may play an important role in the abnormal cellular proliferation seen in benign prostatic hyperplasia.     

Dickkopf‐related protein 3 promotes pathogenic stromal remodeling in benign prostatic hyperplasia and prostate cancer

BACKGROUND

Compartment‐specific epithelial and stromal expression of the secreted glycoprotein Dickkopf‐related protein (Dkk)‐3 is altered in age‐related proliferative disorders of the human prostate. This study aimed to determine the effect of Dkk‐3 on prostate stromal remodeling that is stromal proliferation, fibroblast‐to‐myofibroblast differentiation and expression of angiogenic factors in vitro.

METHODS

Lentiviral‐delivered overexpression and shRNA‐mediated knockdown of DKK3 were applied to primary human prostatic stromal cells (PrSCs). Cellular proliferation was analyzed by BrdU incorporation ELISA. Expression of Dkk‐3, apoptosis‐related genes, cyclin‐dependent kinase inhibitors and angiogenic factors were analyzed by qPCR, Western blot analysis or ELISA. Fibroblast‐to‐myofibroblast differentiation was monitored by smooth muscle cell actin and insulin‐like growth factor binding protein 3 mRNA and protein levels. The relevance of Wnt/β‐catenin and PI3K/AKT signaling pathways was assessed by cytoplasmic/nuclear β‐catenin levels and phosphorylation of AKT.

RESULTS

Knockdown of DKK3 significantly attenuated PrSC proliferation as well as fibroblast‐to‐myofibroblast differentiation and increased the expression of the vessel stabilizing factor angiopoietin‐1. DKK3 knockdown did not affect subcellular localization or levels of β‐catenin but attenuated AKT phosphorylation in PrSCs. Consistently the PI3K/AKT inhibitor LY294002 mimicked the effects of DKK3 knockdown.

CONCLUSIONS

Dkk‐3 promotes fibroblast proliferation and myofibroblast differentiation and regulates expression of angiopoietin‐1 in prostatic stroma potentially via enhancing PI3K/AKT signaling. Thus, elevated Dkk‐3 in the stroma of the diseased prostate presumably regulates stromal remodeling by enhancing proliferation and differentiation of stromal cells and contributing to the angiogenic switch observed in BPH and PCa. Therefore, Dkk‐3 represents a potential therapeutic target for stromal remodeling in BPH and PCa. Prostate 73: 1441–1452, 2013. © 2013 Wiley‐Liss, Inc. The Prostate published by Wiley Periodicals, Inc.