姜黄素对雄激素依赖性前列腺癌细胞的诱导凋亡作用

目的:探讨姜黄素对雄激素依赖性前列腺癌细胞株(LNCaP)的诱导凋亡作用。方法:分别用10、25、50、75、100μmol/L浓度的姜黄素作用于LNCaP细胞,5、12、24 h后MTT法检测细胞生长活性;24 h后流式细胞仪测定细胞周期及细胞凋亡的变化,透射电镜观察细胞超微结构变化;5 h后W estern印迹法检测细胞内IκBα的表达。结果:姜黄素能显著抑制LNCaP细胞的生长,呈剂量与时间依赖性,不同浓度姜黄素组之间与不同作用时间组之间的差异均有显著性意义(P均<0.05)。姜黄素诱导LNCaP细胞出现剂量依赖性G2/M期阻滞(P<0.01),各浓度组凋亡细胞比例均显著高于空白对照组(P均<0.05),差异有显著性意义;姜黄素作用24 h后LNCaP细胞出现凋亡的形态学改变;不同浓度姜黄素作用后,LNCaP细胞内IκBα的表达无变化。结论:姜黄素能显著抑制LNCaP细胞的体外生长,并促进其凋亡。     

苦参碱对雄激素依赖性前列腺癌细胞的影响

目的：探讨苦参碱（Matrine）对雄激素依赖性前列腺癌细胞株（LNCaP）凋亡及前列腺特异抗原（prostate specific antigen,PSA）表达的影响。方法：分别用0.5g／L、1.0g／L、1.5g／L、2.0g／L浓度的苦参碱作用于LNCaP细胞12h、24h、36h后MTT法检测细胞生长活性;24h后流式细胞仪测定细胞凋亡的变化;24h后Western印迹法检测细胞内Bel-2和Bax的表达;12h、24h、36h后化学发光法检测LNCaP细胞培养液中PSA的变化。结果：苦参碱能抑制LNCaP细胞的生长,呈剂量与时间依赖性,不同浓度苦参碱组之间与不同作用时间组之间的差异均有统计学意义（P〈0.05）。苦参碱诱导LNCaP细胞凋亡,各浓度组凋亡细胞比例均显著高于对照组,差异有统计学意义（P〈0.05）;LNCaP细胞内Bcl-2含量呈浓度依赖性下降,Bax含量呈浓度依赖性升高（P〈0.01）;LNCaP细胞培养液中PSA的表达显著下降（P均〈0.05）。结论：苦参碱能显著抑制LNCaP细胞的体外生长,诱导其凋亡,并抑制PSA的表达。     

姜黄素对前列腺癌细胞核转录因子抑制蛋白表达的影响

目的观察姜黄素对前列腺癌细胞核转录因子抑制蛋白(IkBα)表达的影响,探讨姜黄素抑制前列腺癌细胞增殖的作用机制。方法分别用10、25、50、75和100μmol/L 浓度的姜黄素对雄激素依赖性及雄激素非依赖性前列腺癌细胞株 LNCaP 和 PC3进行干预,5、12和24 h 后采用噻唑蓝(MTT)比色法观察细胞增殖情况;采用流式细胞术测定24 h 后细胞周期变化;5 h 后 Western 印迹法检测细胞中 IkBα的表达。结果姜黄素显著抑制 LNCaP 及 PC3细胞的生长,呈剂量和时间依赖性;姜黄素将两种前列腺癌细胞阻滞于 G_2、M 期[LNCaP 与 PC3细胞,空白对照分别为(11.4±1.3)%与(17.3±1.7)%,100μmol/L 姜黄素作用后分别为(27.3±2.8)%与(33.4±4.0)%],从而诱导肿瘤细胞凋亡;姜黄素作用于 LNCaP 细胞后,细胞中 IkBα表达无变化(F=0.129,P>0.05);但作用于 PC3细胞后,细胞中 IkBα的表达明显增强,呈现出显著的剂量依赖性(F=31.618,P<0.05)。结论姜黄素通过活化 IkBα在 PC3细胞中的表达发挥抑制 PC3细胞增殖的作用。对于 LNCaP 细胞,姜黄素可能通过抗氧化、抑制细胞内代谢产物形成等方式抑制 LNCaP 细胞增殖。     

姜黄素对雄激素非依赖性前列腺癌细胞PC-3及血管内皮生长因子的影响

目的:研究姜黄素对雄激素非依赖性前列腺癌细胞株PC-3细胞体外作用及其对血管内皮生长因子(VEGF)表达的影响,探讨其抗肿瘤的作用机制。方法:分别用0、6.25、12.5、25、50μmol/L浓度的姜黄素作用于PC-3细胞,12、24、36、48、72、96h后台盼蓝拒染法、四甲基偶氮唑蓝(MTT)法检测细胞生长活性;24h后流式细胞仪测定细胞周期及凋亡的变化,透射电镜观察细胞超微结构变化;半定量RT-PCR法检测PC-3细胞内VEGFmRNA的表达;ELISA检测细胞上清液中VEGF浓度。结果:姜黄素能显著抑制PC-3细胞的增殖,呈剂量与时间依赖性,不同浓度姜黄素组之间及不同时间组之间差异均有统计学意义(P<0.01)。不同浓度姜黄素诱导PC-3细胞出现剂量依赖性G2/M期阻滞(P<0.01),且各浓度组凋亡细胞比例均显著高于空白对照组(P<0.01),差异有统计学意义;姜黄素作用24h后PC-3细胞出现凋亡的形态学改变;PC-3细胞内VEGF mRNA的表达和细胞上清液中VEGF呈剂量依赖性降低。结论:姜黄素能显著抑制体外PC-3细胞的生长,并促进其G2/M期阻滞和凋亡,VEGFmRNA及蛋白的表达也明显降低,可能是其抑制肿瘤和血管生长的机制之一。     

姜黄素诱导雄激素非依赖性前列腺癌PC3细胞周期阻滞和凋亡研究

目的观察姜黄素对雄激素非依赖性前列腺癌细胞株PC3细胞的生长抑制作用。方法10～100μmol姜黄素作用PC3细胞5～24h后,溴化二甲噻唑二苯四氮唑(MTT)比色法检测细胞生长活性,流式细胞仪检测细胞周期时相及细胞凋亡变化,透射电镜观察细胞超微结构变化,Western印迹法检测细胞内IκBα的表达。结果姜黄素能显著抑制雄激素非依赖性前列腺癌细胞株PC3细胞的体外生长(P<0.05),呈时间与剂量依赖性;姜黄素将PC3细胞周期阻滞于G2/M期;不同浓度姜黄素诱导PC3细胞凋亡率分别为(6.33±0.88)%、(7.53±2.32)%、(12.74±3.02)%、(18.09±2.51)%与(27.54±2.63)%(P<0.05);细胞内IκBα的表达随姜黄素剂量的增加而逐步升高(P<0.05)。结论姜黄素通过抑制PC3细胞增殖、诱导细胞凋亡等机制,显著抑制雄激素非依赖性前列腺癌细胞的体外生长。     

熊果酸对前列腺癌细胞雄激素非依赖性的逆转作用

目的 探讨中药成分熊果酸对雄激素非依赖性前列腺癌(AIPC)的治疗作用及其机制.方法 应用熊果酸处理体外培养的人雄激素依赖性前列腺癌(ADPC)细胞株LNCaP和AIPC细胞株DU145,噻唑蓝(MTT)比色法检测细胞活性及对人工合成雄激素R1881的反应性,免疫细胞化学检测熊果酸对雄激素受体(AR)、糖皮质激素受体(GR)、前列腺特异性抗原(PSA)及成活因子HSP90和白细胞介素(IL)-6表达的影响,逆转录.聚合酶链反应(RT-PCR)检测熊果酸对DU145细胞AR mRNA表达的影响.结果 熊果酸对不同浓度雄激素下的LNCaP细胞均呈浓度和时间依赖性生长抑制,20 mg/L的熊果酸作用96 h对LNCaP细胞的抑制率近50%.0.1 nmoL/L的R1881为最适生长浓度,熊果酸作用后,LNCaP细胞生长的最适雄激素浓度上升了10倍;熊果酸对DU145细胞的生长有浓度和时间依赖性抑制效应,DU145细胞对AR阻断剂羟氟他胺缺乏反应,熊果酸作用同时再应用氟他胺比单纯熊果酸的作用更明显,对细胞抑制率明显上升.熊果酸作用后,LNCaP和DUl45细胞IL-6、HSF90表达均明显下降(P＜0.05),DU145细胞GR表达明显降低(P＜0.01),AR和PSA蛋白及AR mRNA出现再表达.结论 熊果酸能改善前列腺癌细胞对雄激素的反应性,使LNCaP细胞对雄激素的依赖性加强,并诱发了DU145细胞对雄激素的反应性,其部分机制是降低了GR、HSP90、IL-6的表达并促进AR再表达.     

索拉非尼对前列腺癌PC3细胞的抑制作用的研究

目的 观察索拉非尼(Sorafenib)对雄激素非依赖性前列腺癌PC3细胞的抑制作用.方法 用不同浓度Sorafenib处理前列腺癌PC3细胞24h、48h和72h后,用MTT法检测Sorafenib对PC3细胞的抑制作用,流式细胞仪检测细胞凋亡变化,Western blot检测不同浓度Sorafenib处理72h后PC3细胞内ERK和Bcl-2的表达.结果 Sorafenib能显著抑制PC3细胞的体外生长,呈时间与剂量依赖性.PC3细胞凋亡率随着Sorafenib剂量的增加而增大,具有良好的量效关系(P<0.01);Sorafenib处理PC3细胞72h后,ERK和Bcl-2蛋白的表达明显下调(P<0.01).结论 Sorafenib抑制PC3细胞增殖、诱导细胞凋亡,可显著抑制雄激素非依赖性前列腺癌细胞的体外生长.     

龙葵碱对前列腺癌细胞系PC-3的体外抑制作用

目的:探讨龙葵碱对雄激素非依赖型人前列腺癌PC-3细胞的体外抑制作用及其机制。方法:分别用0、30、40、50μg/ml浓度的龙葵碱作用PC-3细胞,12、24、48 h后应用CCK-8法检测细胞生长活性、24 h后流式细胞仪测定细胞周期及细胞凋亡变化,荧光显微镜观察细胞凋亡,24 h后应用Western印迹方法检测细胞内IкBα和Bcl-2蛋白的表达。结果:龙葵碱能显著抑制PC-3细胞的生长,呈剂量与时间依赖性,不同浓度龙葵碱组之间与不同作用时间组之间的差异具有显著性意义(P均<0.05)。龙葵碱诱导PC-3细胞出现S期阻滞(P<0.05),各浓度组凋亡细胞比例均高于对照组,差异有显著意义(P均<0.05);不同浓度龙葵碱作用后,可以上调细胞内IкBα蛋白表达,下调Bcl-2蛋白的表达。结论:龙葵碱可以通过抑制PC-3细胞增殖、诱导凋亡、活化PC-3细胞中IкBα蛋白以及抑制Bcl-2蛋白表达等机制发挥抗前列腺癌作用。     

Sorafenib对前列腺癌DU145细胞的抑制作用的研究

目的 观察索拉非尼(Sorafenib)对雄激素非依赖性前列腺癌DU145细胞的抑制作用.方法 用不同浓度Sorafenib处理前列腺癌DU145细胞24、48和72 h后,MTT法检测Sorafenib对DU145细胞的抑制作用,流式细胞仪检测细胞凋亡变化,Western blot检测不同浓度Sorafenib处理72 h后DU145细胞内ERK和Bcl-2的表达.结果 Sorafenib能显著抑制DU145细胞的体外生长,呈时间与剂量依赖性.DU145细胞凋亡率随着Sorafenib剂量的增加而增大,具有良好的量效关系(P<0.01);Sorafenib处理DU145细胞72 h后,ERK和Bcl-2蛋白的表达明显下调(P<0.01).结论 Sorafenib抑制DU145细胞增殖、诱导细胞凋亡,可显著抑制雄激素非依赖性前列腺癌细胞的体外生长.     

雷公藤内酯醇对前列腺癌细胞PC-3及血管内皮生长因子的影响

目的:探讨雷公藤内酯醇对雄激素非依赖性前列腺癌细胞株PC-3的抑制作用及对血管内皮生长因子(VEGF)表达的影响.方法:分别用0、6.25、12.5、25、50 nmol/L浓度的雷公藤内酯醇作用于PC-3细胞,24 h、48 h、72 h后,以MTT法检测细胞生长活性,24 h后流式细胞仪测定细胞周期及细胞凋亡的变化,透射电镜观察细胞超微结构变化;ELISA法测定培养上清液VEGF的水平.结果:雷公藤内酯醇能以剂量与时间依赖性的方式抑制PC-3细胞的生长,促进其凋亡;细胞周期主要阻滞于S期,部分细胞出现凋亡的形态学改变;VEGF表达较对照组明显降低.结论:雷公藤内酯醇能显著抑制PC-3细胞的体外生长,促进其凋亡,并降低VEGF的表达.     

Downregulation of androgen receptor expression by luteolin causes inhibition of cell proliferation and induction of apoptosis in human prostate cancer cells and xenografts

BACKGROUND: Androgen receptor (ARs) play a crucial role in the development and progression of prostate cancer. Recent studies have suggested that prostate cancer cell proliferation is inhibited by AR downregulation. Our aim was to investigate how luteolin, a natural flavonoid, affects cell growth and AR expression in prostate cancer cells and xenografts. METHODS: We assessed prostate cancer cell (LNCaP, DU145, and PC-3) proliferation and apoptosis by MTT assay, flow cytometric analysis, and Western analysis. AR function was measured by evaluating the AR target molecule, prostate-specific antigen (PSA), by RT-PCR, Western blotting, and enzyme-linked immunosorbent assay. We determined the mechanism of AR downregulation with cycloheximide chase assays, proteasome inhibitor, and coimmunoprecipitation experiments. The effects of luteolin on growth inhibition in vivo were examined by LNCaP xenografts in SCID mice. RESULTS: Luteolin significantly repressed prostate cancer cell proliferation and induced apoptosis in LNCaP cells. PC-3 and DU145 cells were less susceptible to luteolin-mediated growth inhibition. Luteolin simultaneously suppressed intracellular and secreted PSA levels and repressed AR mRNA and protein expression in a dose- and time-dependent manner. Luteolin reduced the association between AR and heat-shock protein 90, causing AR degradation through a proteasome-mediated pathway in a ligand-independent manner. Luteolin also suppressed LNCaP xenograft tumor growth in SCID mice. CONCLUSION: Luteolin-mediated AR downregulation contributes to the inhibition of cell proliferation and the induction of apoptosis in LNCaP human prostate cancer cells, suggesting that AR is a molecular target for luteolin-mediated anticancer activity. Luteolin may act as a chemopreventive or chemotherapeutic agent for prostate cancer.     

Androgen receptor-dependent regulation of Bcl-xL expression: Implication in prostate cancer progression

BACKGROUND: Recently we reported that silencing the androgen receptor (AR) gene reduced Bcl-xL expression that was associated with a profound apoptotic cell death in prostate cancer cells. In this study we further investigated AR-regulated Bcl-xL expression. METHODS: Prostate cancer cell line LNCaP and its sublines, LNCaP/PURO and LNCaP/Bclxl, were used for cell proliferation assay and xenograft experiments in nude mice. Luciferase gene reporters driven by mouse or human bcl-x gene promoter were used to determine androgen regulation of Bcl-xL expression. RT-PCR and Western blot assays were conducted to assess Bcl-xL gene expression. Chromatin immunoprecipitation assay was performed to determine AR interaction with Bcl-xL promoter. Bcl-xL-induced alteration of gene expression was examined using cDNA microarray assay. RESULTS: In cultured prostate cancer LNCaP cells, androgen treatment significantly increased Bcl-xL expression at mRNA and protein levels via an AR-dependent mechanism. Promoter analyses demonstrated that the AR mediated androgen-stimulated bcl-x promoter activation and that the AR interacted with bcl-x promoter. Enforced expression of Bcl-xL gene dramatically increased cell proliferation in vitro and promoted xenograft tumor growth in vivo. Genome-wide gene profiling analysis revealed that Bcl-xL expression was significantly higher in metastatic and castration-resistant diseases compared to normal prostate tissues or primary cancers. Bcl-xL overexpression significantly increased the expression of cyclin D2, which might be responsible for Bcl-xL-induced cell proliferation and tumor growth. CONCLUSIONS: Taken together, our data strongly suggest that androgen stimulates Bcl-xL expression via the AR and that increased Bcl-xL expression plays a versatile role in castration-resistant progression of prostate cancer.     

转化生长因子β对前列腺癌LNCaP细胞株侵袭转移相关蛋白表达的影响及意义

目的:研究在体外培养条件下转化生长因子β(TGF-β)对前列腺癌LNCaP细胞株侵袭转移相关蛋白表达的影响,初步探讨TGF-β在前列腺癌侵袭、转移过程中的作用及可能的机制。方法:利用TGF-β干预处于对数生长期的前列腺癌LNCaP细胞,Western印迹法分别检测不同时间段细胞上皮型钙粘素、神经型钙粘素及波形蛋白的表达情况。结果:LNCaP细胞在TGF-β干预后,细胞侵袭转移的标志性蛋白神经型钙粘素、波形蛋白表达显著上调,以干预后12h最为明显;而上皮型钙粘素表达无明显改变。结论:TGF-β可能通过诱导低转移潜能的前列腺癌LNCaP细胞发生上皮细胞间质性转化,增强PCa的侵袭、转移能力。     

Monomethylated selenium inhibits growth of LNCaP human prostate cancer xenograft accompanied by a decrease in the expression of androgen receptor and prostate-specific antigen (PSA)

OBJECTIVES: Epidemiological studies and prevention trials suggest selenium is a promising preventive agent for prostate cancer. Selenium-containing compounds inhibited the growth of prostate cancer cell lines including androgen sensitive LNCaP and androgen insensitive DU145 and PC3 cells in vitro. Previous study revealed a novel mechanism of selenium action in which selenium (methylseleninic acid (MSA)) markedly reduced androgen receptor (AR) signaling in prostate cancer cells, suggesting that selenium might act as an antiandrogen, which could serve as a therapeutic agent for prostate cancer. In this study, we tested whether selenium (methylselenocysteine (MSC)) affects tumor growth of human prostate cancer cells by targeting AR signaling in vivo. METHODS: Prostate tumor xenografts were established in nude mice by co-inoculating LNCaP cells with Matrigel. The mice-bearing tumors were treated with or without MSC (100 microg/mouse/day) via intraperitoneal injection for 2 weeks. The effect of MSC on tumor growth, AR, and prostate-specific antigen (PSA) expression was examined. RESULTS: Methylselenocysteine (MSC) significantly inhibited LNCaP tumor growth (P < 0.05). AR expression in tumor tissues and serum PSA levels were considerably decreased in MSC-treated mice compared to the vehicle controls. CONCLUSIONS: Pharmacological dose of MSC inhibits the growth of LNCaP human prostate cancer in vivo accompanied by a decrease in the expression of AR and PSA. These findings suggest that selenium (MSC) can serve as a therapeutic agent aimed at disruption of AR signaling for prostate cancer.     

Two mutations identified in the androgen receptor of the new human prostate cancer cell line MDA PCa 2a

PURPOSE: We have characterized the androgen receptor (AR) in a new human prostate cancer cell line, MDA PCa 2a, that has recently been established from a bone metastasis of a patient whose cancer exhibited androgen-independent growth. MATERIALS AND METHODS: Androgen responsiveness of these cells was assessed by measuring the effect of DHT and R1881 on cell growth and PSA secretion. Scatchard analysis was used to characterize the affinity and abundance of AR protein. Using a PCR based strategy, genomic DNA of the entire coding region of AR gene was sequenced to identify possible mutations. RESULTS: These cells express abundant AR (Nmax = 685 +/- 149 fmol./mg. protein), but the AR binding affinity (Kd) for DHT is only 25 nM, approximately 50-fold lower affinity than the mutated AR in LNCaP prostate cancer cells (Kd = 0.5 nM) or the wildtype AR in MCF-7 breast cancer cells (Kd = 0.4 nM). Two mutations, L701H and T877A, were identified in the ligand binding domain of the AR gene. Compared with LNCaP cells, the new cell line is significantly less responsive to DHT and R1881 as well as to other androgens such as testosterone, androstenedione, and DHEA. Similar to LNCaP cells, the ligand specificity of the AR in MDA PCa 2a cells appears to be relaxed and non-androgens such as progesterone and estradiol act as agonists although with less potency than in LNCaP cells. Interestingly, in the absence of androgens, the new cell line expresses 15-fold higher baseline levels of PSA than LNCaP. CONCLUSIONS: Two mutations were identified in the AR gene of the MDA PCa 2a cell line that are likely responsible for the decreased androgen sensitivity and altered ligand specificity observed in these cells. Thus, this new cell line with partial androgen responsiveness and PSA expression can serve as a functionally relevant model system of bone metastatic prostate cancer, and can be used to investigate the role of AR mutations in prostate cancer and its progression to androgen independence.     

Pharmacological potential of phytoestrogens in the treatment of prostate cancer

INTRODUCTION: Phytoestrogenes are plant-derived compounds that have been shown to exert an antiproliferative potential on prostate cancer cells, although the exact mechanisms are still unclear. In prostate cancer cells proliferation is regulated by modulation of the IGF-1 receptor (IGF-R-1) by the androgen receptor (AR) and its co-activator prostate derived Ets factor (PDEF). Phytooestrogenes interact with these mechanisms as demonstrated exemplarily in the presented study with the isoflavone tectorigenin derived from Belamcanda chinensis. MATERIAL AND METHODS: Cultured androgen-sensitive LNCaP prostate cancer cells were treated with tectorigenin of 100 microM for 24 hours. The mRNA-expression of AR, PSA, PDEF, hTERT, TIMP-3 and IGF-R-1 were quantified by real-time RT-PCR. Furthermore, the expression or activity of PSA, telomerase and IGF-R-1 was measured on the protein level. In addition, we investigated in nude mice the influence of a diet of extracts of Belamcanda chinensis on the growth of subcutaneously injected LNCaP cells versus a control group of animals fed with a soy-free diet. RESULTS: In cultured LNCaP cells treatment with tectorigenin resulted in a significant down-regulation of the gene expression of AR, PDEF, PSA, IGF-R-1 and hTERT. On the protein level PSA secretion and the activity of telomerase and IGF-R-1 expression was also decreased. The gene expression of TIMP-3 was distinctly up-regulated by tectorigenin. Nude mice fed with Belamcanda chinensis extract showed a significantly decreased incidence and tumor growth compared to controls. CONCLUSIONS: Tectorigenin shows an inhibition of the IGF-1-R modulated cell proliferation of PCa-Cells, due to modulation of the activity the co-activator PDEF independently from the AR. Furthermore, tectorigenin has pro-apoptotic effects and decreases tissue invasion by up-regulation of TIMP-3. Therefore, phytooestrogenes are an interesting option in the therapy of prostate especially advanced prostate cancer.