缺氧通过下调miR-132表达促进前列腺癌细胞的体外生长和侵袭

目的:探讨miR-132在前列腺癌中的表达及其对前列腺癌细胞生长和侵袭的调节作用,以及缺氧条件下前列腺癌细胞中miR-132水平的变化及其生物学行为的改变。方法:荧光定量PCR分析前列腺癌组织中miR-132的表达水平,分析其与临床分期和Gleason评分的关系,及体外缺氧对人前列腺癌细胞株PC3中miR-132表达的影响;磺酰罗丹明B(SRB)比色法和Matrigel侵袭实验分别检测缺氧和miR-132 mimic质粒转染对PC3细胞活力和侵袭的体外影响。结果:相对于对照组癌旁组织,前列腺癌组织中miR-132水平降低至对照组的52.38%(T1~T2期)(P0.01)和21.59%(T3~T4期)(P0.01)。缺氧培养下,PC3细胞的miR-132水平明显降低(P0.01)。miR-132 mimic质粒转染48 h和72 h后,PC3细胞活力显著降低(P0.05或P0.01);转染后48 h,PC3细胞侵袭力降低了57.5%(P0.01)。然而,miR-132 mimic质粒转染PC3细胞后,常氧和缺氧培养两种方式间的细胞活力和侵袭力均无明显差异(P0.05)。结论:miR-132的表达降低与前列腺癌的临床分期和Gleason评分密切相关;缺氧通过下调miR-132表达,可在体外促进前列腺癌细胞的活力和侵袭,可能进一步促进前列腺癌的生长和转移。     

Elevated physiological levels of folic acid can increase in vitro growth and invasiveness of prostate cancer cells

What's known on the subject? and What does the study add? Evidence has emerged identifying folic acid supplementation as a potential risk factor for cancer development or progression. Long‐term folic acid supplementation has been shown to increase the risk of prostate cancer development by three‐fold. Sarcosine is a byproduct of folate metabolism and has been proposed as a biomarker for aggressive prostate cancer phenotypes. We looked at the effects of physiologically relevant levels of folic acid on in vitro prostate cancer cell growth and invasion, and demonstrated that higher levels can have the effect of increasing both of these biological processes. We also show that these changes toward a more aggressive phenotype are not linked to increased sarcosine levels, however other metabolic pathways may be involved.

OBJECTIVES

• ? To investigate the effects of different folic acid concentrations on the growth and invasiveness of prostate cancer cell lines.
• ? To determine if observed changes are correlated with changes in levels of the potential prostate cancer biomarker, sarcosine, a byproduct of folate metabolism.

MATERIALS AND METHODS

• ? The prostate cancer cell lines PC‐3, LNCaP and DU145 were cultured in media containing 4, 20 or 100 nm of folic acid and assayed for growth over 9 days by counting viable cells at 3‐day intervals, or for invasion by passage through a Matrigel‐coated transwell membrane.
• ? Cells grown in the different folic acid media were collected and subjected to metabolomic analysis by gas chromatography and mass spectrometry to measure levels of intracellular sarcosine.

RESULTS

• ? The results show that higher levels of folic acid can increase cell growth in PC‐3 and LNCaP prostate cancer cell lines, and may also increase the invasive capacity of PC‐3, LNCaP and DU145 cells.
• ? We did not observe a correlation between increased invasion from higher folic acid concentrations and levels of sarcosine, but there were significant changes in other metabolites in cells grown in higher levels of folic acid.

CONCLUSION

• ? These findings suggest that folic acid has an important and potentially negative role in prostate cancer progression.

     

感觉神经肽P物质在表皮干细胞分化中作用的实验研究

目的以体外培养表皮干细胞(ESC)为实验平台，观察感觉神经肽P物质(SP)在ESC分化中的作用。方法以黏附分离法分离、纯化新生Wistar大鼠的ESC，在出现ESC克隆生长时加入SP刺激，分别于刺激前及刺激后24、48、72、96、144、192、240、288、336、384、432h取样进行角蛋白14(K14)免疫组织化学染色并用流式细胞仪(FCM)，鉴定细胞分群及比例。结果ESC在加入SP后可以继续呈片状聚集生长，细胞K14染色阳性，提示为短暂扩充细胞(TAC)。FCM检测结果提示，ESC经SP刺激后出现TAC细胞群落，细胞比例随时间的延长上升。结论SP可以诱导体外培养ESC分化为TAC，在这个过程中ESC数量仍保持一定的水平。     

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。     

Phosphoinositide metabolism in human prostate cancer cells in vitro

To understand better the mechanism by which 5-alpha-dihydrotestosterone (5-alpha-DHT) influences prostate epithelial cell function, we examined the effects of 5-alpha-DHT on phosphoinositide metabolism in human prostate cancer cell lines. Androgen receptor-positive LN-CaP cells showed dose-responsive, steady-state elevations in phosphoinositide metabolism when treated with 5-alpha-DHT. The intracellular pool of 3H-myoinositol decreased and the incorporation of 3H-myoinositol into cellular lipids increased with increasing concentrations of 5-alpha-DHT. 5-alpha-DHT increased the release of 3H-inositol phosphates into the media. The inactive stereoisomer, 5-beta-DHT, did not increase phosphoinositide metabolism. In androgen receptor-negative cells, phosphoinositide metabolism was not altered by 5-alpha-DHT. The slow induction of phosphoinositide metabolism by 5-alpha-DHT suggests that the effects may be mediated through other factors that serve as intermediates in 5-alpha-DHT modulation of intracellular signalling. We conclude that this modulation involves increased turnover of phosphatidylinositol, incorporation of myoinositol into cellular lipids, and alterations in the aqueous intracellular myoinositol pool size, possibly as a result of altered transport mechanisms.     

Suppression of prostate cancer induced bone remodeling by the endothelin receptor A antagonist atrasentan

PURPOSE: We examined the effects of atrasentan (endothelin-A receptor antagonist) on bone deposition and resorption markers and on bone scan index. MATERIALS AND METHODS: This double-blind, randomized, placebo controlled clinical trial of hormone refractory prostate cancer patients was done at 74 medical centers in the United States and Europe. A total of 288 asymptomatic patients with hormone refractory prostate adenocarcinoma and evidence of metastatic disease were randomized to 1 of 3 treatment groups, namely 2.5 mg. atrasentan, 10 mg. atrasentan or placebo administered orally daily until disease progression. The main outcomes measures were changes in bone deposition markers (total alkaline phosphatase and bone alkaline phosphatase) and bone resorption (N-telopeptides, C-telopeptides and deoxypyridinoline), and in the bone scan index. RESULTS: At baseline markers of bone deposition and resorption were elevated 1.4 to 2.7-fold above respective upper limits of normal. Subjects receiving placebo experienced a 58% elevation in mean total alkaline phosphatase and a 99% elevation in mean bone alkaline phosphatase (p < 0.001), whereas subjects receiving 10 mg. atrasentan maintained stable mean total alkaline phosphatase and bone alkaline phosphatase values compared with baseline. N-telopeptides, C-telopeptides and deoxypyridinoline elevation from baseline were consistently less in patients receiving 10 mg. atrasentan compared with placebo. Similar trends were observed in subjects who received 2.5 mg. atrasentan. Changes in clinical bone scan studies paralleled bone marker changes. CONCLUSIONS: Atrasentan suppressed markers of biochemical and clinical prostate cancer progression in bone and demonstrates clinical activity for hormone refractory prostate cancer.     

The novel Ras antagonist, farnesylthiosalicylate, suppresses growth of prostate cancer in vitro

BACKGROUND: The majority of men with advanced prostate cancer (PCa) respond to androgen deprivation therapy (ADT) with objective evidence of tumor regression. However, these tumors will regrow in the presence of low-androgen levels after 12-18 months. Regrowth after ADT is associated with upregulation of growth factor (GF) mediated pathways. The compound farnesylthiosalicylate (FTS), a specific antagonist of the 21 kDa Ras protein, suppresses GF signaling and it might be a useful therapy against advanced PCa. METHODS: We measured androgen and GF dependent growth of androgen dependent LNCaP and androgen hypersensitive CWR-R1 PCa cells in response to specific inhibitors of GF pathways, including FTS. Inhibition of GF mediated signaling and cell-cycle pathways was confirmed by Western blotting of extracts from treated cells. RESULTS: Both LNCaP and CWR-R1 cells were dependent on GF signaling pathways for cell growth. FTS, as well as suppressing cell growth, inhibited GF signaling pathway activity and reduced the levels of E2F1, p-Rb, and p-cdc2, all GF dependent mediators of cell-cycle progression. CONCLUSIONS: These data suggest that FTS might be a useful agent against PCa that has relapsed after ADT.     

The effects of curcumin on the invasiveness of prostate cancer in vitro and in vivo

Curcumin has become a focus of interest with regard to its antitumor effects in prostate cancer; however, the effects of this agent on invasion and metastasis remain less well understood. Matrix metalloproteinases (MMPs) are important prerequisite for tumor invasion and metastasis. In this study, we evaluated the effects of curcumin on prostate cancer cells (DU-145) invasion in both in vitro and in vivo. We utilized zymography and ELISA in order to determine the MMP-2 and MMP-9 activity. Matrigel invasion assay was performed to assess cellular invasion. We developed a xenograft model to examine tumorigenicity. Curcumin treatment resulted not only in a significant reduction in the expression of MMP-2 and MMP-9, but also effected the inhibition of invasive ability in vitro. Curcumin was shown to induce a marked reduction of tumor volume, MMP-2, and MMP-9 activity in the tumor-bearing site. The metastatic nodules in vivo were significantly fewer in the curcumin-treated group than untreated group. Curcumin appears to constitute a potential agent for the prevention of cancer progression, or at least of the initial phase of metastasis, in prostate cancer.     

Induction of urinary plasminogen activator by retinoic acid results in increased invasiveness of human prostate cancer cells PC-3

Overproduction of uPA by prostate cancer cells in vivo results in tumor invasiveness and osteoblastic skeletal metastasis due to its mitogenic actions in osteoblasts. In the present study we have examined the effect of several growth factors and steroid hormones on regulating uPA gene expression in the human prostate cancer cell line (PC-3). Treatment of these cells with dexamethasone (Dex) caused a decrease, whereas epidermal growth factor (EGF) and fetal bovine serum (FBS) increased uPA expression in a dosedependent manner. Trans retinoic acid (RA) also induced uPA mRNA and protein production in a dose-dependent manner (10^?6 to 10^?9 M). This increase was seen as early as 2 hr of treatment until 48 hr. Dex treatment resulted in decreased tumor cells invasiveness, whereas exposure to EGF and RA caused an increase in the invasive capacity of PC-3 cells. These studies should help to better understand the control mechanism of uPA expression in prostate cancer, where uPA has been implicated as a major pathogenetic factor. © 1995 Wiley-Liss, Inc.     

Effect of suramin on human prostate cancer cells in vitro.

Suramin, a polyanionic compound with known antiparasitic activity, has been shown to be adrenocorticolytic in primates and to have clinical efficacy in the treatment of patients with metastatic prostate cancer refractory to conventional hormonal manipulation. To better characterize the activity of suramin on prostate cancer biology, we studied the effect of the drug on plasma adrenal androgens of patients and on the human prostate adenocarcinoma cell lines PC-3, DU 145 and LNCaP-FGC. Five cancer patients treated with suramin had an approximate 40% decline in circulating androstenedione, dehydroepiandrosterone and dehydroepiandrosterone sulfate levels. The drug inhibited the colony formation in two of the three cell lines at concentrations clinically achievable in humans without excessive drug-related toxicity. The presence of suramin 300 micrograms./ml. partially inhibited the growth stimulatory effect of testosterone and basic fibroblast growth factor, but not that of epidermal growth factor. The cellular concentration of suramin following exposure to a single dose increases linearly over time in each of the cell lines with LNCaP-FGC accumulating the highest levels of the drug; cellular levels of suramin, not androgen or growth factor sensitivity, correlated with the sensitivity to the drug. The concentrations of prostatic acid phosphatase and prostatic specific antigen released by LNCaP-FGC cells in cell culture medium declined in the presence of increasing levels of suramin in a manner which exceeded the decrease in cell number. We conclude that suramin, aside from decreasing circulating androgens through its adrenocorticolytic effect, is also capable exerting a direct inhibitory effect on cell proliferation of prostate cancer cells, and interfere at a cellular level with the growth stimulatory effects of exogenous testosterone and basic fibroblast growth factor.     

Erythropoietin stimulates growth and STAT5 phosphorylation in human prostate epithelial and prostate cancer cells

BACKGROUND: Erythropoietin (Epo), the principal regulator of erythroid progenitor survival, growth, and differentiation, initiates its action by binding to its cognate cell surface receptor (EpoR). EpoR have been identified on a variety of non-hematopoietic cells, both normal and malignant, however, little is known about the function of EpoR on malignant cells. METHODS: RT-PCR, Western blotting, and immunohistochemistry were used to demonstrate that prostate cancer cells express EpoR at both the gene and protein level. Cell proliferation assays and STAT5 phosphorylation were used to demonstrate Epo's mitogenic action and intracellular signaling, respectively. RESULTS: We have demonstrated that transformed prostate epithelial and prostate cancer cell lines, as well as primary prostate tissue, express the EpoR. Importantly, the EpoR on prostate cells are functional, as demonstrated by the observation that each of the cell lines exhibited a dose-dependent proliferative response to Epo, and that Epo triggered STAT5b phosphorylation in the cells. CONCLUSION: Human prostatic epithelial cells and prostate cancer cells express functional EpoR, and Epo serves as a growth factor for these cells. These results have implications for our understanding of normal prostatic growth and development and of the pathobiology of human prostate cancer.     

GLI-1参与表皮生长因子介导的前列腺癌ARCaP_E细胞体外侵袭活性强化的实验研究

目的:探讨Hedgehog(HH)信号通路效应蛋白GLI-1在表皮生长因子(EGF)介导的人前列腺癌AR-CaPE细胞系体外侵袭活性增强中的作用。方法:以人前列腺癌ARCaP细胞系作为研究模型,免疫荧光技术鉴定ARCaPE内EGF受体(EGFR)和GLI-1的表达情况;100 ng/ml EGF体外作用于ARCaPE后,观察细胞的形态及体外侵袭能力的变化,采用Western印迹检测细胞内ERK信号通路成分和GLI-1蛋白的表达变化情况;Transwell侵袭实验检测EGF(100 ng/ml)与GLI-1拮抗剂GANT61(10μmol/L)单独或联合作用对ARCaPE细胞体外侵袭能力的影响。结果:ARCaPE细胞同时表达EGFR与GLI-1蛋白;EGF诱导上皮样外观的ARCaPE细胞向间质样外观的AR-CaPM转化,增强ARCaPE细胞的体外侵袭能力并显著上调细胞内p-ERK和GLI-1蛋白的表达水平(P<0.05);GANT61明显抑制ARCaPE细胞的体外侵袭能力且减弱EGF对细胞侵袭能力的增强效应(P<0.05)。结论:HH信号通路和EGF/ERK信号通路之间存在一定的相互作用,GLI-1可能在EGF介导的人前列腺癌ARCaPE细胞体外侵袭活性增强过程中发挥着重要作用。     

人神经生长因子促进感觉神经生长和诱导神经肽释放的实验研究

目的：采用体外模型对比研究观察、评估人椎间盘源性下腰痛( DLBP)椎间盘细胞外基质对小鼠背根神经节神经轴突生长的促进作用和P物质( SP)的诱导作用。方法从DLBP患者的椎间盘组织(实验组)以及腰椎骨折患者腰椎间盘组织(对照组)中提取细胞基质,分别检测神经生长因子( NGF)的含量,并对小鼠背根神经节神经元( DRG )进行培养,通过形态学观察神经轴突生长和酶联免疫吸附法检测SP含量。结果实验组NGF浓度显著高于对照组(P<0．05);神经轴突平均长度实验组为134．17μm ±2．21μm,明显高于对照组的121．28μm ±4．10μm,差异有统计学意义( P <0．05)。实验组中 SP 物质比率明显高于对照组( P <0．01)。结论人退变椎间盘细胞外基质中高表达的NGF能促进感觉神经轴突的生长以及诱导和疼痛相关神经肽的释放。     

Osteopontin enhances the cell proliferation induced by the epidermal growth factor in human prostate cancer cells

BACKGROUND: Susceptibility to extracellular matrix and growth factors has been demonstrated to play a critical role in the development of prostate cancer (PCa) metastases. The aim of this study was to elucidate some mechanisms by which stroma controls tumor progression. METHODS: In our study we tested the growth ability of the LNCaP human prostatic cell line in steroid-free culture conditions in response to osteopontin (OPN), a non-collageneous matrix protein, localized in large amounts in the bone. RESULTS: In the LNCaP cell model, OPN stimulates cell proliferation in serum-free medium and colony growth at high dilution but this effect is visible only in presence of epidermal growth factor (EGF). Proliferation induced by OPN is accompanied by a sustained activation of EGF receptor (EGFR) whose phosphorylation is detectable up to 12 hr after treatment in association with EGF. The colocalization of integrin beta1, a ligand of OPN, and of EGFR on the cellular membrane, suggests that the association of these cell surface receptors may be the principal mechanism involved in the long-term activation of the EGFR. CONCLUSIONS: Our data describe a new possible mechanism involved in the establishment of bone metastases which may also account for the formation of androgen-independent cellular clones, frequently responsible of the clinical progression of PCa.