Wnt/β-catenin信号通路在多种人前列腺癌细胞系中的表达研究及意义

目的:检测多种不同上皮细胞间质转化(EMT)特性的人前列腺癌细胞Wnt/β-catenin信号通路关键蛋白的表达,对细胞中Wnt/β-catenin信号通路的功能状态进行鉴定,分析其在前列腺癌EMT现象中可能的作用。方法:用Western印迹法鉴定LNCaP及其亚细胞系C4、C4-2、C4-2B和ARCaP亚细胞系IF11、IA8,以及PC-3、DU145细胞中β-连环素(β-catenin),糖原合成酶3β(t-GSK3β),磷酸化糖原合成酶3β(p-GSK3β)的表达差异情况。结果:β-catenin和p-GSK3β在LNCaP、C4、C4-2、C4-2B、IF11、IA8中表达较高,在PC-3中表达较低,在DU145中表达缺失,t-GSK3β在上述所有细胞中表达无明显差异。p-GSK3β/t-GSK3β比值在LNCaP、C4、C4-2、C4-2B、IF11、IA8中较高,在PC-3和DU145中较低。结论:8种不同EMT特性的前列腺癌细胞系中,Wnt/β-catenin信号通路的功能状态存在差异。     

缺氧诱导因子1α诱导人前列腺癌细胞上皮间质化改变的研究

目的:研究人前列腺癌细胞在缺氧诱导因子1α(HIF-1α)诱导下能否发生上皮细胞间质转化态(EMT)改变,进而致侵袭能力增强,并初步分析其分子机制。方法:应用RT-PCR技术检测LNCaP细胞及其亚细胞系C4、C4-2、C4-2B这4种EMT阴性的人前列腺癌细胞中波形蛋白(vimentin)mRNA表达情况,并凭此筛选出适合于进一步作转染诱导试验的细胞。用脂质体Lipofectamine2000包装重组真核表达载体pCDNA3.1(-)/HIF-1α和pCD-NA3.1(-)空质粒后,分别转染上步试验所挑选出的人前列腺癌细胞LNCaP,600μg/mLG418筛选抗性克隆。免疫荧光及Western印迹法鉴定HIF-1α表达,Western印迹法检测EMT标志蛋白——上皮型钙粘素(E-cadherin)和vimentin的表达,Transwell验证转染后LNCaP细胞侵袭能力的改变。结果:RT-PCR证实4种EMT阴性的细胞中,仅LNCaP表达有vimentin编码基因,适合作转染诱导试验。免疫荧光也观察到HIF-1α转染细胞胞质中荧光亮度较空质粒转染细胞和未转染细胞明显增强。Western印迹法证实HIF-1α转染细胞发生了EMT转化,其E-cad-herin表达缺失,而vimentin表达增加。同时,Transwell体外侵袭试验也发现,LNCaP/HIF1α细胞的体外侵袭能力显著高于LNCaP细胞和LNCaP/pCDNA3.1(-)细胞。结论:HIF-1α过表达可以通过调节两种EMT相关蛋白诱导人前列腺癌细胞LNCaP发生EMT改变并致其侵袭能力增强。     

多种转移潜能不同的人前列腺癌细胞“上皮细胞间质转化态”特性鉴定及其意义

目的:对多种转移潜能不同的人前列腺癌细胞“上皮细胞间质转化态”(EMT)特性进行鉴定,并从粘附因素和细胞骨架蛋白角度分析其骨转移潜能获得的分子机制。方法:用W estern印迹法鉴定LNCaP及其亚细胞系C4、C4-2和ArCaP亚细胞系IF11、IA8,以及PC-3、Du145等细胞中上皮型钙粘素(E-cadherin)、神经型钙粘素(N-cadherin)和波形纤维蛋白(V im entin)的表达差异情况,并分析其在前列腺癌转移过程中的作用。结果:E-cad-herin在PC-3、LNCaP、C4、C4-2中表达较高,但在Du145、IF11、IA8中表达极低;而V im entin的表达情况恰恰与E-cadherin相反;N-cadherin在IF11、IA8细胞中呈现显著的高表达状态。结论:转移潜能不同的人前列腺癌细胞株之间存在EMT表型的表达差异,其中PC-3、LNCaP、C4、C4-2是未发生EMT改变的细胞,Du145、IF11、IA8却是EMT化的细胞。EMT表型差异蛋白在解释前列腺癌转移机制方面占据着重要地位。     

TGF-β/Smads通路关键蛋白在5种前列腺癌细胞株中表达的鉴定及意义

目的:对多种不同人前列腺癌细胞株TGF-β/Smads信号通路的"开放"或"关闭"状态进行鉴定,初步探讨此通路在前列腺癌侵袭、转移中的作用及可能的机制。方法:用Western印迹法检测LNCaP、PC-3、DU145及AR-CaP亚细胞系IF11、IA8细胞中TGF-β/Smads通路的关键蛋白TGF-βⅡ型受体(TβRⅡ)、Smad2/3、磷酸化Smad2(p-Smad2)、Smad4的差异表达。结果:TβRⅡ在PC-3、DU145、IF11、IA8中表达较高,在LNCaP中表达极低;Smad2/3在所有细胞中表达均较高,但活性成分p-Smad2仅在PC-3、DU145中表达;Smad4在LNCaP、PC-3、DU145中表达较高,IF11、IA8中表达缺失。结论:不同转移潜能的前列腺癌细胞株TGF-β/Smads通路的"开闭"状态存在差异,仅PC-3、DU145细胞处于开放状态;前列腺癌细胞可能通过不同的方式改变TGF-β/Smads通路状态参与晚期肿瘤的侵袭、转移过程。     

γ-干扰素对前列腺癌细胞粘附和侵袭能力影响的初步研究

目的：探讨γ-干扰素对前列腺癌细胞粘附和侵袭行为的影响。方法：用纤维粘连蛋白和层粘连蛋白处理细胞培养板，检测γ-干扰素对前列腺癌细胞系LNCaP和PC-3粘附作用的影响；用Transwell小室，以Matrigel和纤维粘连蛋白构建基底膜，检测γ-干扰素对前列腺癌细胞侵袭人工基底膜能力的影响；应用Western-blot法检测γ-干扰素对前列腺癌细胞膜粘连蛋白-2（annexin-2）表达的影响。结果：γ-干扰素未处理的两种人前列腺癌细胞系细胞LNCaP、PC-3粘附率分别为46％和40％，γ-干扰素处理的两种细胞系细胞LNCaP、PC-3粘附率分别为21％和23％，同种细胞系γ-干扰素处理组与未处理组间差异有显著性（P均〈0．05）。在相同细胞系γ-干扰素处理组较未处理组前列腺癌细胞24h侵袭能力明显降低（P均〈0．05）。Western印迹结果表明γ-干扰素可显著抑制annexin-2蛋白的表达（P〈0．05）。结论：γ-干扰素可能通过下调annexin-2的表达来抑制前列腺癌细胞的粘附和侵袭。     

粘附分子E-钙粘素/β-连环素在LNCaP和ARCaP亚细胞系中的差异性表达及意义

目的:检测粘附分子E-钙粘素/β-连环素(E-cadherin/β-catenin)复合体在LNCaP和ARCaP亚细胞系IF11、IA8中的差异性表达,以探讨E-cadherin/β-catenin复合体与前列腺癌转移侵袭的关系。方法:用Western印迹及免疫荧光鉴定LNCaP和ARCaP亚细胞系IF11、IA8中E-cadherin、β-catenin的表达以及分布情况。结果:Western印迹显示E-cadherin在LNCaP细胞系中表达较高,在IF11、IA8中表达缺失,β-catenin在IF11、IA8中表达显著高于LNCaP(P<0.01)。免疫荧光显示β-catenin在LNCaP细胞系中主要分布在细胞膜上,而在ARCaP亚细胞系IF11、IA8中,主要分布于细胞核中;E-cadherin在LNCaP细胞中主要分布在细胞膜上。结论:不同上皮细胞间质转化态(EMT)特性的前列腺癌细胞系中E-cadherin/β-catenin表达以及分布存在差异,β-catenin的核转位可能是诱发前列腺癌细胞系发生EMT改变的机制之一。     

缺氧诱导因子1α过表达对前列腺癌细胞血管生成能力的影响

目的:观察转染缺氧诱导因子1α(HIF-1α)对人前列腺癌细胞血管形成相关蛋白的影响,并探讨其分子机制。方法:用脂质体Lipofectamine2000包装重组真核表达载体pCDNA3.1(-)/HIF-1α后转染人前列腺癌细胞LNCaP,600μg/ml G418筛选稳定表达的抗性克隆。免疫荧光及Western印迹法鉴定HIF-1α过表达,Western印迹法检测血管形成相关蛋白血管内皮生长因子(VEGF)、iNOS、促血管生成素2(Ang-2)。结果:与未转染细胞LN-CaP相比,转染细胞LNCaP/HIF-1α中出现明显的HIF-1α蛋白条带,并激发出较强荧光,VEGF、iNOS表达增加,Ang-2未见明显变化。结论:HIF-1α过表达能够诱导LNCaP细胞血管形成相关蛋白表达增多,进而增强其体外血管形成能力。     

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.     

Smad4在人前列腺癌细胞系LNCaP和ARCaP中的差异表达及意义

目的:探讨TGF-β/Smads信号转导的核心Smad4在前列腺癌转移潜能获得中的作用及可能的机制。方法:用Millicell体外侵袭试验观察LNCaP和ARCaP系IF-11、IA-8细胞株转移潜能的差异情况,分别应用Western印迹法和逆转录PCR鉴定这3种细胞株中Smad4蛋白及mRNA的差异表达。结果:ARCaP系IF-11、IA-8细胞株的体外侵袭潜能明显高于LNCaP细胞(P<0.01);但Smad4蛋白在低转移潜能的LNCaP细胞中高表达,而在高转移潜能的IF-11、IA-8中表达缺失(P<0.01),Smad4 mRNA表达结果与蛋白一致。结论:Smad4在转移潜能不同的前列腺癌细胞系间存在差异表达,Smad4表达缺失可能是晚期前列腺癌发生侵袭转移的机制之一。     

缺氧诱导因子1α诱导前列腺癌LNCaP细胞上皮间质转化的体内外研究

目的:探讨在体内外环境下缺氧诱导因子1α(HIF-1α)过表达对前列腺癌细胞发生上皮间质转化(EMT)并导致肿瘤侵袭能力升高的影响。方法:对已构建的稳定表达HIF-1α的人前列腺癌LNCaP细胞(LN-CaP/HIF-1α)复苏后培养,对HIF-1α过表达进行鉴定。MTT法测定细胞增殖;检测转染前后培养液上清PSA水平;软琼脂成瘤实验比较两种细胞体外成瘤能力;将转染前后的LNCaP细胞注射免疫裸鼠皮下建立皮下肿瘤模型,观察肿瘤生长情况;收集肿瘤标本进一步行免疫组化处理。结果:免疫荧光和Western印迹证实LNCaP/HIF-1α细胞中HIF-1α过表达。同LNCaP细胞相比,转染HIF-1α的人前列腺癌LNCaP细胞培养液中PSA水平明显降低;MTT法显示其更具有增殖活性,体外成瘤能力更强。体内实验显示皮下肿瘤成瘤率提高,成瘤时间提前。肿瘤标本免疫组化提示转染组E钙粘蛋白表达下调,波形蛋白表达上调。结论:HIF-1α过表达能够封闭E钙粘蛋白,上调波形蛋白表达,提示HIF-1α过表达可能通过诱导EMT增强LNCaP细胞侵袭能力。     

槲皮素通过G3BP1调控Wnt/β-catenin信号通路对前列腺癌细胞迁移、侵袭及上皮-间充质转化的影响

目的探讨槲皮素对前列腺癌(PCa)细胞迁移、侵袭及上皮-间充质转化(EMT)的影响,并分析其可能机制。方法人前列腺癌细胞(PC-3)随机分为空白对照组及槲皮素低、中、高浓度组,转染GTP酶激活蛋白-Src同源结构域3-结合蛋白1(G3BP1)siRNA及其阴性对照、pcDNA3.1-G3BP1及其阴性对照至PC-3细胞,并用槲皮素处理。分别采用细胞划痕试验和Transwell小室法检测细胞迁移、侵袭能力,实时荧光定量PCR(qRT-PCR)法检测G3BP1 mRNA表达,Western blot法检测G3BP1蛋白、EMT相关蛋白及Wnt/β-连环蛋白(β-catenin)通路蛋白表达。结果槲皮素抑制PC-3细胞迁移、侵袭,上调E-钙黏蛋白(E-cadherin)表达,下调N-钙黏蛋白(N-cadherin)、波形蛋白(Vimentin)、转录因子Snail表达;槲皮素下调PC-3细胞G3BP1 mRNA和蛋白表达,下调Wnt家族成员3A(Wnt-3α)、β-catenin、磷酸化糖原合成酶激酶3β(Glycogen synthase kinase-3β,p-GSK-3β)表达,上调GSK-3β表达;沉默G3BP1增强槲皮素对PC-3细胞及Wnt/β-catenin通路的作用,过表达G3BP1逆转槲皮素对PC-3细胞及Wnt/β-catenin通路的作用。差异均有统计学意义(P<0.05)。结论槲皮素可通过抑制EMT抑制PCa细胞的迁移、侵袭能力,其作用机制可能与其靶向G3BP1抑制Wnt/β-catenin信号通路相关。     

过表达缺氧诱导因子1α影响前列腺癌血管生成的体内研究

目的:观察转染缺氧诱导因子1α(HIF-1α)在体内环境下对人前列腺癌血管形成的影响,并探讨其分子机制。方法:对构建的转染HIF-1α人前列腺癌LNCaP细胞(LNCaP/HIF-1α)复苏后培养,ELISA法检测转染前后培养液上清PSA水平;流式细胞术检测细胞周期;将转染前后的LNCaP细胞建立免疫裸鼠皮下肿瘤模型,观察肿瘤生长情况;收集肿瘤标本后针对肿瘤血管生成相关蛋白血管内皮生长因子(VEGF),诱导型一氧化氮合酶(iN-OS),促血管生成素2(Ang-2)行免疫组化染色。结果:与LNCaP细胞相比,转染HIF-1α的人前列腺癌LNCaP细胞培养液PSA水平明显降低(t=8.243,P<0.05);流式细胞术显示其更具有增殖活性。体内实验显示皮下肿瘤成瘤率提高,成瘤时间提前。LNCaP/HIF-1α免疫组化研究显示VEGF、iNOS、Ang-2表达较LNCaP组增强。结论:在体内环境下,HIF-1α过表达能够诱导人前列腺癌LNCaP细胞血管形成相关蛋白VEGF、iNOS表达上调,提高肿瘤血管形成能力。并通过诱导肿瘤血管形成来增强肿瘤的侵袭转移能力;体内外实验显示HIF-1α可能对人前列腺癌LNCaP细胞Ang-2表达不产生影响,而在体内环境下Ang-2表达受其他因素调控。     

细胞株源人前列腺肿瘤干细胞的分选与鉴定

目的:论证人前列腺癌(prostate cancer,PCa)细胞株中是否存在干细胞亚群。方法:分别用免疫表型法和侧群(side population,SP)细胞法从5种人PCa细胞株(Du145、IA8、LNCaP、TSU-PrL和PC-3)中富集类干细胞,再应用软琼脂克隆形成试验初步验证类干细胞亚群的体外生长方式及成瘤能力。选择LNCaP源SP细胞(LNCaP/SP),依次采用免疫细胞化学技术、Transwell、MTT以及裸鼠致瘤试验,分别检测其干细胞标记物的表达情况、鉴定其体外增殖和侵袭能力以及动物体内的致瘤和转移潜能。结果:5种细胞株中均难以分选出免疫表型为CD133+CD44+的细胞亚群。除PC-3外,其余4株细胞可分选出呈现典型克隆性生长特点的SP细胞。体外克隆形成率在IA8、LNCaP和TSU-PrL源SP细胞与非侧群(non-side population,NSP)细胞间有显著性差异(P<0.05)。与LNCaP/NSP相比,LNCaP/SP的体外增殖和侵袭能力显著增强,同时阳性表达整合素α2、Nanog、CD44、OCT4以及ABCG2等5种干细胞标记物。而且,LNCaP/SP的皮下成瘤率、骨转移率及瘤体体积亦显著高于LNCaP/NSP(P<0.01)。结论:SP分选法更适合富集人PCa细胞株中类干细胞,LNCaP/SP细胞是PCa细胞株LNCaP中的肿瘤干细胞(cancer stem cell,CSC)。     

Synthetic retinoid CD437 induces S-phase arrest and apoptosis in human prostate cancer cells LNCaP and PC-3

BACKGROUND: Exposure of prostate carcinoma cell lines to retinoids, which function through the classical retinoic acid nuclear receptor, (RARs) or retinoid X receptors (RXRs), results in minimal cytostatic inhibition of cell proliferation. METHODS: Growth inhibition and various regulatory responses were investigated in two human prostate carcinoma cell lines (LNCaP and PC-3) treated with or without a synthetic retinoid, CD 437. RESULTS: Incubation of prostate carcinoma cell lines with a novel retinoid CD437 resulted in the marked inhibition of proliferation. LNCaP and PC-3 possessed IC50 values for CD437 of 375 nM and 550 nM, respectively. Incubation with 1 microM CD437 for 24 hr resulted in 100% and 60% inhibition of growth in LNCaP and PC-3 cells, respectively. Simultaneously, cell flow cytometric analyses revealed a dramatic increase of the cell population in S phase, in both LNCaP (from 38.6% up to 86.7%) and PC-3 (27.9% to 55.7%), and a decreased proportion of cells in G2 phase, in LNCaP (from 23.7% down to 1.2%) and PC-3 (14.9% to 2.2%), indicating a significant S-phase arrest. The cell growth inhibition and S-phase arrest in these cells were followed by apoptosis, as revealed by the acquisition of the characteristic cell morphology including the appearance of apoptotic bodies, and further confirmed by cellular DNA fragmentation. CD437-induced-S phase arrest was associated with upregulated mRNA levels of p21waf1/cip1/sdi1 in both LNCaP (p53+/+) and PC-3 (53-/-) cells. CONCLUSIONS: CD437 represents a unique retinoid that induces S-phase arrest and apoptosis in both androgen-dependent (LNCaP) and -independent (PC-3) human prostate cancer cells, suggesting a potential role of CD437 in the treatment of human prostate cancer.     

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。     

两种不同前列腺癌上皮细胞间质转化模型转录调控因子的比较及意义

目的:初步筛选、对比决定两种不同前列腺癌上皮细胞间质转化(EMT)模型(LNCaP/HIF1α细胞模型、ARCaP细胞模型)表型的转录因子,为利用这两个模型深入研究前列腺癌转移机制奠定基础。方法:分别体外培养LNCaP/HIF1α细胞模型中的LNCaP细胞、稳定高表达缺氧诱导因子HIF1α的LNCaP细胞和ARCaP细胞模型中的IF11细胞、IA8细胞,提取总RNA行RT-PCR,检测目前发现的决定EMT表型的5种转录因子(Snail、Slug、ZEB1、SIP1、Twist1),对比两种模型的差异。结果:LNCaP/HIF1α细胞模型中的两种细胞均不同程度地表达5种转录因子,其中Slug、Twist1有差异,表型转化后Slug表达升高,而Twist1表达降低(P<0.05);ARCaP细胞模型中的两种细胞均不同程度地表达Snail、Slug、ZEB1、SIP1,不表达Twist1,其中ZEB1、Slug有差异,表型转化后ZEB1、Slug表达升高(P<0.05)。结论:决定不同来源的前列腺癌EMT模型表型转化的转录调控机制各不相同,Slug可能是决定HIF1α诱导LNCaP细胞EMT表型转化的关键转录因子,而ZEB1、Slug则可能在ARCaP细胞EMT表型转化中起决定作用。     

Secreted frizzled-related protein 4 inhibits proliferation and metastatic potential in prostate cancer

BACKGROUND: Secreted frizzled-related proteins (sFRP4) inhibits Wnt signaling and thus cellular proliferation in androgen-independent prostate cancer cells in vitro. However, increased expression of membranous sFRP4 is associated with a good prognosis in human localized androgen-dependent prostate cancer, suggesting a role for sFRP4 in early stage disease. Here, we investigated the phenotype of sFRP4 overexpression in an androgen-dependent prostate cancer model. METHODS: An sFRP4-overexpressing androgen-dependent (LNCaP) prostate cancer model was established to assess changes in cellular proliferation, the expression, and subcellular localization of adhesion molecules and cellular invasiveness, and compared with the findings in sFRP4-overexpressing androgen-independent cells (PC3). RESULTS: sFRP4 overexpression in both cell line models resulted in a morphologic change to a more epithelioid cell type with increased localization of beta-catenin and cadherins (E-cadherin in LNCaP, N-cadherin in PC3) to the cell membrane. Functionally, sFRP4 overexpression was associated with a decreased rate of proliferation (P = 0.0005), decreased anchorage-independent growth (P < 0.001), and decreased invasiveness in PC3 cells (P < 0.0001). Furthermore, increased membranous sFRP4 expression was associated with increased membranous beta-catenin expression (P = 0.02) in a cohort of 224 localized human androgen-dependent prostate cancers. CONCLUSIONS: These data suggest that sFRP4 is an inhibitor of prostate cancer growth and invasion in vitro independent of androgen receptor (AR) signaling with correlative evidence in human androgen-dependent disease suggesting similar changes in the clinical setting. Consequently, potential therapeutic strategies to modulate Wnt signaling by sFRP4 will be relevant to both localized androgen-dependent prostate cancer and advanced metastatic disease.     

Down-regulation of prostasin serine protease: a potential invasion suppressor in prostate cancer.

BACKGROUND: Prostasin is a serine protease predominantly expressed in normal prostate epithelial cells. The biological function of prostasin has not been determined. METHODS: Western blot and RT-PCR analyses were used to examine the expression of prostasin in prostate cancer cell lines. Immunohistochemistry was used to evaluate prostasin protein expression in human prostate cancer. An in vitro Matrigel invasion assay was used to test the invasiveness of prostate cancer cell lines forced to express recombinant prostasin. RESULTS: Both prostasin protein and mRNA were found to be expressed in normal human prostate epithelial cells and a non-invasive human prostate cancer cell line, the LNCaP, but neither was found in invasive human prostate cancer cell lines DU-145 and PC-3. Prostasin mRNA expression was absent in invasive prostate cancer cell lines of a transgenic mouse model. Immunohistochemistry analysis showed that prostasin protein expression is down-regulated in high-grade prostate cancer. Transfection of DU-145 and PC-3 cells with a full-length human prostasin cDNA restored prostasin expression and reduced the in vitro invasiveness by 68 and 42%, respectively. CONCLUSIONS: Our data indicate that prostasin may be implicated in normal prostate biology and is able to suppress prostate cancer invasion in vitro.