前列腺癌细胞中表皮生长因子受体的表达和激活

目的：探讨前列腺癌（ＰＣａ）细胞中表皮生长因子受体（ＥＧＦＲ）表达和激活及其与雄激之间的相互作用。方法：采用免疫沉淀和Ｗｅｓｔｅｒｎ ｂｌｏｔ方法,检测雄激素依赖人ＰＣａ细胞株ＬＮＣａＰ及雄激素非依赖人ＰＣａ细胞株ＤＵ－１４５、ＰＣ－３中ＥＧＦＲ的表达和磷酸化激活,测定雄激素对ＬＮＣａＰ ＥＧＦＲ表达和激活的影响。结果：在ＤＵ－１４５和ＰＣ－３中,ＥＧＦＲ表达和激活的基础与表皮生长因子（ＥＧＦ）处     

PI-3K和p38MAPK通路在EGF诱导PC-3细胞环氧化酶-2表达上调中的作用

目的:研究p38丝裂原激活蛋白激酶(p38MAPK)和磷脂酰肌醇-3激酶(PI/3K)通路在表皮生长因子(EGF)诱导的激素非依赖性前列腺癌(hormone-refractory prostate cancer,HRPC)PC-3细胞环氧化酶2(cyclooxygen-ase-2,COX-2)表达上调中的作用。方法:MTT法检测EGF(0μg/L)、EGF(10μg/L)、EGF(10μg/L)+PI-3K阻断剂(LY294002,20μmol/L)、EGF(10μg/L)+p38MAPK阻断剂(SC203580,20μmol/L)处理后的细胞增殖情况。RT-PCR和Western印迹测定上述处理24h后PC-3细胞COX-2的表达变化,ELISA测定细胞培养液中前列腺素E2(PGE2)的变化。结果:LY294002和SC203580明显抑制EGF刺激后的PC-3细胞增殖(P<0.05)及EGF诱导的COX-2上调和PGE2生成(P<0.05)。结论:PI-3K通路和p38MAPK通路可能参与了EGF诱导的PC-3细胞COX-2的表达上调。     

有丝分裂激活蛋白激酶在人前列腺癌细胞中的激活

目的 探讨前列腺癌（PCa)细胞中有丝分裂激活蛋白激酶（MAPK）的激活。方法 采用免疫沉淀和Western blot方法,检测人PCa细胞株LNCaP及DU－145中磷酸化MAPK的表达及雄激素或表皮生长因子（EGF）对其表达的影响。结果 在DU－145中,磷酸化MAPK表达本底水平比LNCaP高10倍。雄激素和EGF处理后8hLNCaP中MAPK激活水平升高,24h达最高,分别比本底高约10倍和5倍,在DU－145中仅EGF可促使MAPK激活水平升高,8h开始升高,24h达最高,比本底高约10倍。结论 在雄激素非依赖性人PCa细胞增生中,MAPK激活比在雄激素依赖性人PCa细胞中作用大,MAPK激活也参与了雄激素和EGF的增生刺激作用。     

Antagonists of growth hormone releasing hormone (GHRH) and of bombesin/gastrin releasing peptide (BN/GRP) suppress the expression of VEGF, bFGF, and receptors of the EGF/HER family in PC-3 and DU-145 human androgen-independent prostate cancers

BACKGROUND: Antagonists of growth hormone releasing hormone (GHRH) as well as antagonists of bombesin/gastrin releasing peptide (BN/GRP) inhibit the growth of various malignancies (cancers) including prostate cancer. METHODS: We investigated the effects of GHRH antagonists MZ-J-7-118 and RC-J-29-18, BN/GRP antagonists RC-3940-II and RC-3940-Et and the combination of MZ-J-7-118 and RC-3940-II on the growth of PC-3 and DU-145 human androgen independent prostate cancers xenografted s.c. into nude mice. To elucidate the mechanisms of action of these analogs, growth factors like IGF-II (insulin-like growth factor-II), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and epidermal growth factor receptor/human epidermal growth factor receptor (EGF-R/HER) family were measured in tumors as well as IGF-I in serum. RESULTS: Antagonists of GHRH and BN/GRP alone or in combination significantly inhibited growth of PC-3 and DU-145 tumors, the greatest inhibition of tumor volume being achieved by combination of MZ-J-7-118 (5 microg/day) and RC-3940-II (10 microg/day). BN/GRP and GHRH antagonists and their combination also decreased the expression of VEGF significantly in PC-3 and non-significantly in DU-145, as measured by radioimmunoassay for VEGF protein and RT-PCR for mRNA levels of VEGF. GHRH and BN/GRP antagonists reduced bFGF concentrations and the maximal binding capacity of EGF receptors, and their mRNA levels in PC-3 and DU-145 tumors. mRNA levels for HER-2 and -3 were also diminished in PC-3 tumors by GHRH and BN/GRP antagonists. No changes in HER-4 were found after treatment. Serum IGF-I and tumoral IGF-II levels were not affected by the analogs. CONCLUSIONS: BN/GRP and GHRH antagonists inhibit growth of PC-3 and DU-145 prostate cancers by suppressing the expression of tumoral growth factors such as VEGF and bFGF as well as the receptors for EGF and related HER-2 and -3. Additive effects on tumor inhibition (TI) in vivo, but not on VEGF, bFGF, or members of the EGF/HER receptor family, can be achieved by the joint administration of both classes of analogs.     

类固醇受体辅活化子-1和核受体辅阻遏子在雄激素非依赖性前列腺癌的表达及临床意义

目的 探讨类固醇受体辅活化子-1（SRC-1）、核受体辅阻遏子（NCoR）在雄激素非依赖性前列腺癌（AIPC）的表达及临床意义。方法 采用免疫组化法检测20例激素依赖性前列腺癌（ADPC）、15例AIPC组织AR、SRC-1及NCoR表达。结果 1例AIPC无AR表达，其余AIPC及ADPC高表达AR。AIPC、ADPC均检测到SRC-1表达。SRC-1在AIPC的阳性率较ADPC组织明显升高（P〈0．01）。NCoR在AIPC、ADPC均有表达，但在AIPC的表达则出现明显降低（P〈0．01）。结论 SRC-1在AIPC表达升高和／或NCoR在AIPC表达降低引起的AR异常活化可能与前列腺癌（Pca）的进展有关。     

Androgen-independent growth is induced by neuropeptides in human prostate cancer cell lines

BACKGROUND: Androgen-independent growth leads to progressive prostate cancer after androgen-ablation therapy. This may be caused by altered specificity of the androgen receptor (AR), by ligand-independent stimulation of the AR, or by paracrine growth modulation by neuropeptides secreted by neuroendocrine (NE) cells. METHODS: We established and characterized the androgen-independent FGC-DCC from the androgen-dependent LNCaP fast growing colony (FGC) cell line. The androgen-independent DU-145, FGC-DCC, and PC-3, and the androgen-dependent LNCaP and PC-346C cell lines were used to study growth modulation of gastrin-releasing peptide (GRP), calcitonin (CT), serotonin (5-HT), and vasoactive intestinal peptide (VIP) by (3)H-thymidine incorporation. Specificity of the growth-modulating effects was tested with the anti-GRP monoclonal antibody 2A11 and induction of cAMP by neuropeptides. RESULTS: Androgen-independent growth stimulation by neuropeptides was shown in DU-145 and PC-346C. 2A11 inhibited GRP-induced (3)H-thymidine incorporation in DU-145 and PC-346C and inhibited proliferation of the FGC-DCC and PC-3 cell lines. With some exceptions, cAMP induction paralleled growth stimulation. Dideoxyadenosine (DDA) inhibited the GRP-induced growth effect in DU-145 and PC-346C, whereas oxadiazoloquinoxaline-1-one (ODQ) had no effect on (3)H-thymidine incorporation. None of the neuropeptides stimulated growth of LNCaP, FGC-DCC, or PC-3. CONCLUSIONS: GRP-induced growth of DU-145 and PC-346C was specific and cAMP-mediated. Androgen-independent growth of FGC-DCC cells was mainly due to an induction of Bcl-2 expression and possibly through the activation of an autocrine and NE-like pathway, as has been shown also for the PC-3 cell line. Growth induction of non-NE cells by neuropeptides could be a possible role for NE cells in clinical prostate cancer.     

Changes in beta-2 microglobulin expression in prostate cancer

Increased shedding of beta-2 microglobulin (B2m, 11.8 kDa), a component of the major histocompatibility complex class I (MHC I), by tumor cells has significance with regard to escape from immune-surveillance, cellular proliferation, and tumor development and progression. Aberrant expression of MHC I is known to occur in prostate cancer (PCa) but not in benign prostatic hyperplasia. We have determined B2m released by PCa cells in culture and in the urine of 101 patients with advanced PCa by Western blotting and radioimmunoassay. B2m levels in the conditioned medium of human PCa cell lines and primary cultures derived from distant metastasis as well as in the urine of patients with bone and visceral metastasis were higher than normal and also higher than those from patients with local/regional extensions of the disease. In the group of patients with bone metastasis (66 patients), high urine B2m was associated with significantly shortened survival. In addition to the 11.8 kDa B2m, a high molecular weight B2m immunoreactivity of approximately 38 kDa was found in highly tumorigenic PC-3 cell line, but not in the relatively indolent DU-145 and LNCaP human PCa cell lines. The approximately 38 kDa B2m was found in the urine of several PCa patients but not of healthy controls examined by Western analysis. The conditioned medium of a prostatic small cell carcinoma cell line, NCI-H660, had high levels of chromogranin A and B2m, but prostate specific antigen was absent. In conclusion, increased B2m shedding was associated with distant metastasis of PCa and an abnormal B2m immunoreactivity was found in PCa.     

米非司酮诱导雄激素非依赖性前列腺癌细胞凋亡的实验研究

目的探讨米非司酮在体外诱导雄激素非依赖性前列腺癌DU-145、PC-3细胞凋亡的作用。方法采用四甲基偶氮唑蓝法检测1,10,50和100μmol／L米非司酮作用于前列腺癌DU-145、PC-3细胞24～120h的吸光度（A）值,用流式细胞仪检测10μmol／L米非司酮作用24和48h后DU．145、PC-3细胞凋亡率的变化;采用免疫组化法检测米非司酮作用DU-145、PC．3细胞后bax、bcl-2、血管内皮生长因子（VEGF）蛋白表达的变化。结果1μmol／L米非司酮组的A值与对照组相比,差异无统计学意义（P〉0．05）;10,50和100μmol／L米非司酮组的A值与对照组比较,差异有统计学意义（P〈0．01）;米非司酮对前列腺癌DU-145、PC-3细胞的抑制作用呈时间-剂量依赖性。10μmol／L米非司酮作用前列腺癌DU-145细胞24和48h的凋亡率分别为15．3％和30．4％,PC-3细胞的凋亡率分别为22．2％和32．0％。经10μmol／L米非司酮作用后,DU-145、PC-3细胞中VEGF和bcl-2蛋白的表达明显减少,而bax的表达显著增加（P〈0．05）。结论米非司酮以时间．剂量依赖性方式抑制激素非依赖性前列腺癌DU-145和Pc-3细胞的增殖,其作用可能是通过降低VEGF蛋白的表达。从而下调bcl-2、激活bax蛋白的表达来实现。     

Multiple Molecular pathways explain the anti-proliferative effect of valproic acid on prostate cancer cells in vitro and in vivo

BACKGROUND: Valproic acid (VPA), is a drug approved by the FDA for epilepsy and bipolar disorders. It is a known Histone Deacetylase Inhibitor (HDACI). We tested VPA, for its anti-proliferative activity in prostate cancer (PCa) cell lines in vitro and in vivo. METHODS: DU-145 and PC-3 PCa cell lines were cultured with different doses of VPA. Cells were examined for their viability, cell cycle status and expression of cell cycle arrest, and proliferation markers. Nude mice bearing xenografts of human PCa cell lines, DU-145, and PC-3, were administered VPA in their drinking water. RESULTS: VPA displayed a dose- and time-dependent anti-proliferative effect on DU-145 and PC-3 PCa cell lines in vitro. A sustained effect of the drug was seen on cell cycle arrest even at 24 hr after removal of the drug, after which the effects returned to the basal state. Administration of 0.4% w/v VPA in drinking water (resulting in 0.4 mM VPA, in plasma) was effective in inducing growth arrest, cell death, and senescence in vivo and was also anti-angiogenic. The activation of all or some of these anti-proliferative pathways may be contingent on acetylation status of histones, confirmed by detection of increased acetyl-H3K9 in VPA-treated samples when compared with untreated controls. Pharmacodynamic studies showed an increase in expression of p21 and decrease in PCNA in xenografts of VPA-treated mice compared with protein expression in untreated controls. CONCLUSIONS: VPA may be functioning as an HDACI to inhibit growth of PCa cells in vitro and in vivo by modulating multiple pathways including cell cycle arrest, apoptosis, angiogenesis, and senescence.     

Prostasin基因在前列腺细胞株中表达情况研究

目的 探讨Prostasin在前列腺癌中的功能。方法 运用RT-PCR方法检测人前列腺增生细胞株BPH-1，无转移能力前列腺癌细胞株LNCaP，及有转移能力的前列腺癌细胞株PC-3、DU-145中Prostasin基闪表达情况。结果 Prostasin基斟在BPH-l和LNCaP中正常表达，在PC-3、DU-145中低表达。BPH-l中Prostasin的表达与DU-145和PC-3比较差异有显著性，同样LNCaP中Prostasin的表达与DU-145和PC-3比较差异亦有显著性（P〈0．01）。BPH-1与LNCaP之间表达差异无显著性，DU-145和PC-3之间表达差异亦无显著性，（P〉0.05）。结论 ProStasin可能是前列腺癌的转移抑制剂。     

基于文献挖掘的雄激素非依赖型前列腺癌特异表达基因的生物信息学分析

目的:比较雄激素依赖型与非依赖型前列腺癌的基因表达差异,加深对雄激素非依赖型前列腺癌形成的分子机制的认识,为前列腺癌防治找到新的有效手段。方法:通过FACTA工具从PubMed找出前列腺癌的相关基因进行分类,利用GATHER、PANTHER、STRING和ToppGene等在线工具对雄激素非依赖型前列腺癌特异表达基因进行生物信息学分析。结果:筛选雄激素非依赖型前列腺癌特异基因128个,这些特异表达基因在细胞信号转导、凋亡、肿瘤生成、细胞粘附、细胞增殖和分化等生物学过程起着重要作用。结论:通过生物信息学对雄激素非依赖型前列腺癌特异表达基因的挖掘发现,MMP9、EGFR、MMP2、ADM、MIF、IGFBP3、IL2、MET、BAD、RHOA、SPP1、EP300、SMAD3、RAF1、PTK2、TGFB2等基因在雄激素依赖型转变成非依赖型前列腺癌中可能起着重要作用。     

Increased expression and differential phosphorylation of stathmin may promote prostate cancer progression

BACKGROUND: Proteins which regulate normal development may promote tumorigenesis, tumor progression, or metastasis through dysregulation of these functions. We postulate that proteins, which regulate prostate growth also promote prostate cancer (PCa) progression. METHODS: Two Dimensional Gel Electrophoresis was utilized to compare patterns of protein expression in 12T-7f prostates (LPB-Tag mouse model for PCa) during tumor development and progression with those of normal developing and adult wild type CD-1 prostates. Stathmin expression and phosphorylation patterns were analyzed in mouse and human PCa cell lines as well as in human PCa tissue arrays. RESULTS: Stathmin was identified by two-dimensional gel electrophoresis and mass spectrometry. Stathmin levels increase early during normal mouse prostate development and again during prostate tumor development and progression. In human prostate adenocarcinoma, stathmin increases in Gleason pattern 5. Further, stathmin is differentially phosphorylated in androgen-dependent LNCaP cells compared to androgen-independent PC-3 and DU145 cells. This differential phosphorylation is modulated by androgen and anti-androgen treatment. CONCLUSION: Stathmin expression is highest when the prostate is undergoing morphogenesis or tumorigenesis and these processes may be regulated through differential phosphorylation. Furthermore, modulation of stathmin phosphorylation may correlate with the development of androgen-independent PCa.     

环氧化酶2在不同前列腺癌细胞系中的表达

目的:研究环氧化酶2(COX-2)在不同前列腺癌细胞系中的表达,探讨COX-2在前列腺癌侵袭进展及转移潜能获得机制中的可能作用。方法:应用Western印迹及RT-PCR鉴定LNCaP及其亚细胞系C4-2和AR-CaP亚细胞系IF11、IA8,以及PC-3细胞中COX-2的表达情况,并初步分析其在不同特性前列腺癌细胞系转移侵袭过程中的作用。结果:Western印迹结果显示:COX-2蛋白在PC-3细胞中表达相对较高,在IF11、IA8、LNCaP和C4-2细胞中表达缺失,差异具有统计学意义(P<0.05)。COX-2mRNA表达结果同蛋白一致。结论:不同来源、不同转移潜能的前列腺癌细胞株中COX-2表达存在差异。高表达COX-2可能在PC-3细胞高侵袭转移潜能获得方面起着一定作用,而与其他细胞系转移作用无关。     

苦参碱抑制人雄激素非依赖性前列腺癌细胞系PC-3细胞增殖和诱导凋亡机制的研究

目的 探讨苦参碱抑制雄激素非依赖性前列腺癌细胞株PC-3增殖、诱导细胞凋亡的可能机制,为临床雄激素非依赖性前列腺癌的治疗提供一定的实验基础和理论依据.方法 应用活性Caspase-3检测、Western blot印迹分析不同浓度苦参碱作用PC-3细胞后其Caspase-3表达的差异,并通过荧光免疫细胞化学染色、Western blot印迹分析研究不同浓度苦参碱对PC-3细胞Bax/Bcl-2表达的影响.结果 Caspase-3检测显示不同浓度苦参碱均可上调Caspase-3表达.随着苦参碱浓度的增加,Caspase-3表达的荧光强度升高,Caspase-3/β-actin积分密度值亦升高,呈现剂量依赖性关系(P<0.01).Bax、Bcl-2蛋白表达分析显示不同浓度苦参碱作用PC-3细胞后,Bax蛋白的表达增加,Bcl-2蛋白表达下降.Bax表达的荧光强度及Bax/β-actin积分密度值随着苦参碱浓度的增加而升高,呈现剂量依赖性关系(P<0.01);Bcl-2表达的荧光强度及Bcl-2/β-actin积分密度值随着苦参碱浓度的增加而下降,亦呈现剂量依赖性关系(P<0.01).结论 苦参碱抑制PC-3细胞增殖并诱导细胞凋亡可能涉及到了线粒体.细胞色素C/Caspase-9/Caspase-3途径.     

表皮生长因子受体和环氧化酶-2在前列腺癌中的共同表达和意义

目的:探讨表皮生长因子受体(Epidermal growth factor receptor,EGFR)和环氧化酶-2(Cyclooxyge-nase-2,COX-2)在前列腺癌(Prostate cancer,PCa)中的共同表达和临床意义.方法:采用免疫组织化学法(SP)测定48例PCa中EGFR和COX-2阳性表达情况,按免疫组织化学结果分为EGFR(-)COX-2(-)、EGFR(-)COX-2( )、EGFR( )COX-2(-)和EGFR( )COX-2( )四组,分析它们表达与临床病理和预后的关系.结果:EGFR、COX-2阳性在PCa中为34例(70.8%)、21例(45.8%),两者的表达在PCa中无相关性(r＝0.04,P＝0.80),EGFR和COX-2共同表达有16例(33.3%),和Gleason评分、PSA水平有关(P<0.05),5年复发率83.1%,显著高于EGFR( )COX-2(-)(27.8%)、EGFR(-)COX 2( )(16.7%)和EGFR(-)COX-2(-)(12.5%)(P<0.05);13例转移PCa中有10例为EGFR( )COX-2( )(62.5%),显著高于其他三组(P<0.05).结论:EGFR和COX-2在PCa中表达无相关性,但其共同表达可以作为判断PCa预后的重要标志.     

Effects of interferon beta ser and transforming growth factor beta on prostatic cell lines

The effect of interferon beta ser (IFN beta ser) on the growth of three prostatic cancer cell lines DU-145, PC-3 and LNCaP was studied. IFN beta ser inhibited growth of anchorage dependent semiconfluent monolayers and anchorage dependent colony formation of both DU-145 and PC-3 in a dose dependent manner but had no effect on LNCaP. Transforming growth factor beta (TGF beta 1) inhibited proliferation of DU-145 and PC-3 cells in 1% but not 8% fetal calf serum. The combination of TGF beta 1 and IFN beta ser was additive in its effects on growth. Neither epidermal growth factor (EGF) nor transforming growth factor alpha (TGF alpha) reduced the antiproliferative effect of IFN beta ser on these cells. These antiproliferative effects were reproduced in studies on primary epithelial cell cultures derived from prostate specimens with various pathologies. The potential use of IFN beta ser in combination with hormonal therapy to delay the development of hormone refractory tumors is discussed.     

Effects of selected chemotherapeutic agents on PCNA expression in prostate carcinoma cell lines

Bivariate flow cytometric analysis of proliferating cell nuclear antigen (PCNA) was performed on prostate carcinoma cell lines (PC-3, DU-145). For both cell lines 100% methanol fixation provided optimal fluorescence intensity of PCNA. The ratio of PCNA/DNA increased in late G1 through early S/phase, followed by a decrease in mid- and late S and enhancement in G2/M phase. PCNA expression was increased in G2/M phase cells treated for 48 h with vinblastine. A slight decrease in PCNA expression was observed with cyclohexamide treatment. Hydroxyurea induced an increase in S-phase fraction along with enhanced PCNA expression. Methotrexate and Adriamycin had little effect on the cell cycle compartments of PC-3 or DU-145; however, methotrexate decreased PCNA expression, while Adriamycin enhanced it. Cisplatin increased S-phase in both cell lines, increasing PCNA expression in PC-3 and decreasing it in DU-145 cells. The data on the effects of drug treatment point to a dissociation between PCNA expression and S-phase fraction as calculated from the DNA distribution. In some cases, e.g., the cisplatin studies, different effects were obtained in the two different cell lines treated with the same drugs. Whether changes in PCNA expression will provide more useful information than S-phase fraction for evaluation of potential antitumor drugs is not known.Supported by NIH grants Ro-1-CA 14134     

Raf-1 expression may influence progression to androgen insensitive prostate cancer

BACKGROUND: Recent evidence has implicated the MAP kinase pathway with the development of androgen insensitive prostate cancer (AIPC). We have previously reported gene amplification of critical members of this pathway with the development of androgen insensitive disease. METHODS: Protein expression of Raf-1 was analyzed using immunohistochemistry (IHC) in a database of 65 paired tumor specimens obtained before and after the development of AIPC and correlated with other members of the pathway. RESULTS: Patients whose Raf-1 expression rose with development of AIPC had a significantly shorter median time to biochemical relapse compared to those whose expression fell or remained unchanged (1.16 vs. 2.62 years, P = 0.0005). In AIPC tumors, expression of Raf-1 correlated significantly with expression of HER2 and with expression of c-fos. CONCLUSIONS: We conclude that the HER2/Raf-1/AP-1 axis may promote the development of AIPC, leading to early relapse. Members of the pathway may act as novel therapeutic targets for patients.     

MAPK途径磷酸化激活人前列腺癌雄激素受体的研究

目的研究粒细胞-巨噬细胞集落刺激因子（GM-CSF）激活人激素非依赖性前列腺癌PC-3M细胞雄激素受体及其可能的信号转导途径。方法将人雄激素受体和雄激素受体激活报告基因氯霉素乙酰转移酶（CAT）转染至人雄激素非依赖性前列腺癌细胞株PC-3M,不同浓度的GM- CSF以及特异性Erk1／2磷酸化阻断剂PD98059作用后检测雄激素受体报告基因CAT表达量的变化和促分裂素原活化蛋白激酶（MAPK）途径：Erk1／2分子磷酸化的改变。结果20～100 nmol／L的GM-CSF均能激活PC-3M细胞的外源性雄激素受体,CAT的相应表达量为（0．58±0．16）～（3．80±0．89）ng／mg,CAT表达量与培养基中的GM-CSF浓度成正相关;同时检测到PC-3M细胞中Erk1／2分子磷酸化程度与培养基中的GM-CSF浓度相关,在终浓度50 mmol／L的PD98059阻断Erk1／2分子磷酸化后CAT表达量显著下降。结论GM-CSF能独立激活前列腺癌PC-3M细胞中的雄激素受体,Erk1／2分子磷酸化可能是GM-CSF旁路激活人前列腺癌细胞雄激素受体的机制。     

Expression of gonadotropin-releasing hormone (GnRH) and GnRH receptor mRNA in prostate cancer cells and effect of GnRH on the proliferation of prostate cancer cells

The purpose of this study was to determine the production of gonadotropin-releasing hormone (GnRH), the co-occurrence of GnRH receptors in prostate cancer cells, and the effect of GnRH on prostate cancer cell proliferation. Four human prostate cancer cell lines were studied. LNCaP is an androgen sensitive prostate cancer cell line, DU-145 and PC-3 are androgen resistant, and TSU-Pr1 is uncharacterized. The expression of GnRH and GnRH receptor mRNAs were assessed by in situ hybridization and the effect of exogenous GnRH on proliferation of prostate cancer cells was measured by thymidine incorporation assay. GnRH mRNA expression, determined by in situ hybridization, was found in 83.48% of the LNCaP, 89.7% of the TSU-Pr1, 86.2% of the PC-3 and 95.3% of the DU-145. Signals of GnRH receptor mRNA were detected in more than 95% of the cells of all four cell lines. The proliferation of the prostate cancer cells grown in media supplemented with peptide hormone lacking charcoal-stripped serum was significantly (P < 0.05) suppressed. No significant effect of GnRH on the proliferation of all four prostate cancer cells was observed. In summary, prostate cancer cells produced GnRH and its receptors, and exogenous GnRH treatment did not affect the prostate cancer cell proliferation. The existence of GnRH and GnRH receptor mRNA in the same cell suggests that the role of GnRH produced by prostate cancer cells would be autocrine. Received: 21 August 1997 / Accepted 15 April 1998