晚期糖基化终末产物与其受体相互作用对足细胞凋亡的影响

目的 探讨可溶性与复合型晚期糖基化终末产物(AGE)与晚期糖基化终末产物受体（RAGE）的相互作用对足细胞凋亡的影响。 方法 以可溶性（CML-BSA、AGE-BSA）和复合型（AGE修正胶原Ⅳ）AGE刺激小鼠足细胞，并用浓度分别为10、50、100 mg/L的AGE刺激细胞，应用TUNEL染色和荧光激活细胞分类（FACS）法来计数凋亡和坏死的足细胞。用RAGE iRNA转染足细胞后，以同样剂量的可溶性和复合型AGE刺激足细胞，观察凋亡情况的改变。 结果 可溶性和复合型AGE均可诱导小鼠足细胞凋亡，复合型AGE引起的足细胞凋亡是可溶性AGE的2~3倍（均P < 0.01）。AGE呈剂量依赖性引起足细胞凋亡。用RAGE iRNA转染足细胞，降低60%~70%RAGE基因活性后，可溶性AGE引起的凋亡率明显下降，复合型AGE诱导的凋亡有下降趋势，但不明显。只有在AGE 100 mg/L刺激后才发生细胞坏死。结论 可溶性AGE主要通过与RAGE相互作用引起足细胞凋亡，复合型AGE部分通过与RAGE相互作用诱导足细胞凋亡。减少AGE生成和RAGE表达可能是预防肾脏病进展的重要途径。     

前列腺癌细胞系及组织中α-1,6岩藻糖基转移酶的表达及意义

目的 探讨α-1,6岩藻糖基转移酶(α-1,6 fucocyltransferase,FUT8)在不同前列腺癌细胞系、癌及癌旁组织中的表达差异及其意义.方法 培养前列腺正常上皮细胞(RWPE-1)、4种前列腺癌细胞(22RV1、LNCap、PC-3、DU145)及2种其他类型泌尿系统肿瘤细胞(T-24、786-O),收集15对前列腺癌及癌旁组织,提取总RNA,采用RT-PCR检测不同细胞系、癌及癌旁组织中FUT8 mRNA的表达,并进行差异比较.结果 FUT8 mRNA在前列腺癌细胞系中的表达高于前列腺正常上皮细胞系(RWPE-1)、膀胱癌细胞系(T-24)以及肾癌细胞系(786-O).雄激素非依赖性前列腺癌细胞系(PC-3、DU145)中FUT8 mRNA的表达高于雄激素依赖性前列腺癌细胞系(LNCap);前列腺癌转移灶细胞系(PC-3、DU145)中FUT8 mRNA的表达高于前列腺癌原发灶细胞系(22RV1).同时还发现,FUT8 mRNA在前列腺癌组织中的表达高于癌旁组织.以上差异均有统计学意义(P<0.01).结论 FUT8在不同前列腺癌细胞系、癌及癌旁组织中存在差异表达,可能参与前列腺癌的雄激素非依赖性转化及进展转移等过程.     

Expression of estrogen receptor (ER-alpha and ER-beta) mRNA in human prostate cancer.

OBJECTIVE: The distribution of the two estrogen receptors (ER-alpha, ER-beta) in human prostate tissue have not been fully clarified, so the present study investigated the mRNA expression of the receptors to explain the broad spectrum of estrogen activity in prostate cancer. MATERIALS AND METHODS: Four human prostate cancer cell lines (LNCap, JCA-1, DU-145 and PC-3) and 24 pairs of untreated prostate cancer tissue and noncancerous tissue from resected prostate glands were subjected to RT-PCR testing. RESULTS: Both LNCap and JCA-1 expressed the mRNA of both receptors, but DU-145 and PC-3 only expressed ER-beta mRNA. In the human prostate tissue samples, 20 of the 24 prostate cancer tissues expressed ER-alpha, and 23 of the 24 expressed ER-beta. Of the 24 noncancer tissues, 14 expressed ER-alpha mRNA and 17 expressed ER-beta mRNA. The incidence of ER-beta mRNA expression between the paired cancer and noncancer tissues was statistically significantly different (p<0.05). CONCLUSIONS: A higher incidence of ER-beta mRNA expression in untreated prostate cancer tissues was observed. Furthermore, the absence of ER-alpha mRNA and the presence of ER-beta mRNA expression in hormone-independent and/or untreated prostate cancer cells leads to a tentative speculation of the mechanism of the hormone refractory feature of prostate cancer.     

Expression of a human cell adhesion molecule, MUC18, in prostate cancer cell lines and tissues

BACKGROUND: Over expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. METHODS: RT-PCR and Western blot analyses were used to analyze the expression of MUC18 mRNA and protein in four human prostate cancer cell lines, cultured primary normal prostate epithelial cells, normal prostate and malignant prostate tissues. Immunohistochemistry was used to determine the expression of MUC18 antigen in prostatic tissues at different stages of malignancy. RESULTS: Human MUC18 mRNA and protein was expressed in three different prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one prostate cancer cell line (LNCaP.FGC). HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from either cultured primary normal prostatic epithelial cells or the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas and in cells of a lymph node metastasis compared to that in normal or benign hyperplastic epithelium (BPH). CONCLUSIONS: We therefore conclude that MUC18 is expressed at higher levels in pre-malignant and malignant prostatic epithelium, including metastasis. We suggest that over-expression of MUC18 may be a new marker of human prostate cancer and also implicates its possible role in development and progression of prostate cancer.     

Prostate cancer cell proliferation is influenced by leptin

BACKGROUND: Obesity is considered a risk for many cancers. Serum leptin levels are often elevated in obese people. Leptin acts as a mitogenic agent in many tissues; therefore, it may act to promote cancer cell growth. We previously demonstrated that leptin acts as a growth factor for prostate cancer cells in vitro. The purpose of this study was to characterize leptin receptor isoform mRNA expression in leptin-treated DU145 and PC-3 prostate cancer cell lines. Expression levels of SOCS-3, a known leptin-inducible suppressor of leptin signaling, and known mitogenic signaling pathways of PI3K and ERK were also analyzed METHODS: DU145 and PC-3 cells were treated with 0, 4, 40, or 80 ng/ml leptin for 0, 0.5, 1, 2, 4, 24, or 48 h. Multiplex RT-PCR was performed to determine mRNA levels of the short (huOB-Ra) or the long (huOB-Rb) OB-R isoforms or SOCS-3. p-Akt and p-ERK were determined by Western blot. Cell viability and apoptosis were determined by MTT and nucleosomal fragmentation assay RESULTS: DU145 and PC-3 expressed huOB-Ra, huOB-Rb, and SOCS-3 mRNA. huOB-Ra mRNA levels increased in PC-3 at 48 h (P < 0.01); however, no significant changes were observed in DU145. huOB-Rb mRNA levels decreased at 48 h in DU145; however, a twofold increase at 48 h (P < 0.01) was observed with PC-3 and was dose-dependent (P < 0.05). Leptin increased SOCS-3 mRNA in DU145 at 24 and 48 h (P < 0.05) and in PC-3 at 1 h (2-fold) and 48 h (fivefold; P < 0.01). Leptin up-regulated p-Akt in a time- and dose-dependent manner in the DU145 prostate cancer cells via a suppression of apoptosis. Leptin up-regulated p-ERK in a time-dependent manner in PC-3 cells CONCLUSIONS: In prostate cancer cells, the mitogenic effects of leptin are not a consequence of altered receptor isoform mRNA expression. No defect in SOCS-3 signaling was observed, and proliferation appears to be working through the PI3K and MAPK leptin receptor-activated pathways, depending on cell type. Leptin stimulation may be selective for either pathway to suppress apoptosis, thereby enhancing prostate cancer growth.     

V domain of RAGE interacts with AGEs on prostate carcinoma cells

BACKGROUND: The expression of the scavenger receptor for advanced glycation end products (RAGE) and various ligands of RAGE correlate significantly with cancer progression. However, the mechanism of RAGE/sRAGE-induced cancer cell activation and ligand usage remain largely unknown. METHODS: Androgen-independent, highly invasive, as well as androgen-dependent, non-invasive human prostate carcinoma (CaP) cells were investigated for their interaction with the soluble form of RAGE (sRAGE). Using neutralizing antibodies and soluble proteins, the ligand for RAGE was identified on CaP cells and ligand binding with sRAGE was biochemically characterized. RESULTS: Both androgen-independent, highly invasive and androgen-dependent, non-invasive CaP cells interacted with immobilized sRAGE in a surprisingly strong manner. Using C-terminal truncation variants of RAGE we identified the V domain being responsible for the adhesion of CaP cells to sRAGE. Moreover, we demonstrate that this adhesion cannot be blocked by S100B or neutralizing antibodies against beta integrins, or amphoterin. However, the CaP cell-RAGE interaction was inhibited with either AGE-modified proteins, or with neutralizing antibodies against AGE or RAGE. Despite similar binding kinetics between AGE-modified BSA and different RAGE domains, only applying an excess of sRAGE, but not the VC1 or V domain of RAGE, was able to block the CaP cell-RAGE interaction. CONCLUSIONS: We identified AGEs as the ligand for RAGE on both invasive and non-invasive prostate cancer cells.     

人晚期糖基化产物受体在前列腺癌和正常前列腺组织的表达差异

目的:研究人晚期糖基化产物受体(receptor for advanced glycation end product,RAGE)在前列腺癌和正常前列腺组织中的表达差异,为进一步研究RAGE在前列腺癌发病机制中的作用奠定基础。方法:以同一患者的前列腺癌组织和正常前列腺组织配对作比较,采用免疫组化染色法、免疫印迹法、实时荧光定量PCR等方法分别从组织水平、蛋白质水平、mRNA水平检测10例患者前列腺癌和正常前列腺组织中RAGE的表达。结果:免疫组化结果显示RAGE在前列腺癌组织中的表达水平明显高于正常前列腺组织,Western印迹检测发现前列腺癌组织RAGE的表达量是正常前列腺组织的2.13倍(Р<0.05),荧光定量PCR检测前列腺癌中RAGE的mRNA表达水平是正常前列腺组织的4.2倍(Р<0.05)。结论:RAGE在前列腺癌的发生和发展过程中可能起重要作用。     

Hormone-refractory prostate cancer cells express functional follicle-stimulating hormone receptor (FSHR)

PURPOSE: Understanding growth regulation in hormone-refractory prostate cancer may provide avenues for novel treatment interventions. This study was conducted to characterize the expression of the receptor (FSHR) for follicle-stimulating hormone (FSH) in androgen-independent prostate cancer cell lines and in human malignant prostate tissues. MATERIALS AND METHODS: Western blotting, immunohistochemistry (IHC), and flow cytometric analysis were used to study the expression of FSHR. The effect of FSH on cell growth and clonogenicity was studied using proliferation and clonogenic assays. RESULTS: Immunohistochemistry revealed expression of FSH in PC3 and Du145 cells. FSHR was identified in PC3 and Du145 cells, as well as in human adenocarcinoma of the prostate. The specificity of the FSHR detected on prostate cancer tissues or cells by IHC and Western blotting was confirmed by preabsorbing the antibodies with the immunizing antigens. Stimulation of these hormone-refractory cells with FSH triggered a proliferative response in vitro, suggesting that the receptor is biologically active. CONCLUSION: Hormone-refractory prostate cancer cells express FSH and biologically active FSHR. Our results suggest that FSHR and its ligand may play a role in the regulation of the growth of hormone-refractory prostate cancers.     

Hormonal regulation of beta2-adrenergic receptor level in prostate cancer

BACKGROUND: Androgen deprivation is the only effective systemic therapy available for patients with prostatic carcinoma, but is associated with a gradual transition to a hormone-refractory prostate cancer (HRCAP) in which ligand-independent activation of the androgen receptor has been implicated. The beta(2)-adrenergic receptor (beta(2)-AR) is a well-known activator of the androgen receptor. METHODS: Prostatic cell lines were analyzed using cDNA micro-array, real time RT-PCR, radioligand binding assay, cAMP measurements, transfection and thymidine incorporation assay. Clinical specimens were studied by immunohistochemistry and Affymetrix microarrays. RESULTS: Here, we show that beta(2)-AR was transiently down-regulated both at mRNA- and protein levels when hormone-sensitive prostate cancer cells, LNCaP, were cultured in steroid stripped medium (charcoal-stripped fetal calf serum) or when the cells were treated with the anti-androgen, bicalutamide (Casodex). The number of beta-adrenergic receptors was modestly up-regulated in androgen independent cell lines (LNCaP-C4, LNCaP-C4-2 and DU145) compared to LNCaP. Triiodothyronine (T3) increased the level of beta(2)-AR and the effect of T3 was inhibited by bicalutamide. Immunohistochemical staining of human prostate specimens showed high expression of beta(2)-AR in glandular, epithelial cells and increased expression in malignant cells compared to benign hyperplasia and normal tissue. Interestingly, beta(2)-AR mRNA was strongly down-regulated by androgen ablation therapy of prostate cancer patients. CONCLUSION: The level of beta(2)-AR was increased by T3 in prostatic adenocarcinoma cells and reduced in prostate cancer patients who had received androgen ablation therapy for 3 months.     

Regulation of lnvasive Potential of Human Prostate Cancer Cell Lines by Hepatocyte Growth Factor

Background: The growth and progression of prostate cancer depends on the stromal-epithelial interaction which is under paracrine control. Hepatocyte growth factor (HGF), produced by mesenchymal cells, is a multifunctional growth factor stimulating the movement and growth of epithelial cells including cancer cells. We therefore assessed the relationship between the invasive potential of prostate cancer and HGF in vitro.
Methods: Three human prostate cancer cell lines were used including PC-3 and DU145 (androgenindependent), and LNCaP (androgen-dependent). We studied the expression of the HCF receptor c-met proto-oncogene (c-met) by Western blotanalysis, and alsodetermined theeffectsof HGF on cell scattering, and the mechanisms of invasion and proliferation, by microscopic observation, the matrigel invasion chamber assay, and the MTT assay.
Results: c-met was detected in PC-3 and DU145 cells, but not in the LNCaP cells. There was increased cell motility in the scatter assay and an increased cell invasive potential in the matrigel invasion chamber assay by stimulation with HGF only with DU145 cells.
Conclusion: HGF plays an important role in the invasion and metastasis of the DU145 cell line through a paracrine mechanism mediated by the c-metreceptor. In the PC-3 cell line, the lack of downstream signal transduction after the c-met receptor is suggested.     

Prostate stromal cell-derived hepatocyte growth factor induces invasion of prostate cancer cell line DU145 through tumor-stromal interaction.

BACKGROUND: In prostate cancer, several growth factors derived from stromal cells regulate tumor cell growth. Hepatocyte growth factor (HGF) possesses biological activities that promote cancer proliferation and invasion through tumor-stromal interaction. We examined how prostate stromal cell-derived HGF affects invasion of prostate cancer cells through this interaction. METHODS: The effects of HGF, various growth factors (transforming growth factor (TGF)-alpha, TGF-beta1, basic fibroblast growth factor, keratinocyte growth factor, and platelet-derived growth factor), and conditioned medium (CM) from prostate stromal cells (PrSC) on prostate cancer cells (LNCaP, PC-3, and DU145) were determined by collagen gel invasion assay. DU145 cells and PrSC were cocultured for Matrigel invasion chamber assay. Induction activity of CM from cancer cells to stimulate HGF production by PrSC was studied by the ELISA method and Western blotting. RESULTS: LNCaP and PC-3 cells did not respond to any of the factors examined. Invasion of DU145 cells into the collagen gel matrix was induced by HGF and TGF-beta1, but not by any of the other factors tested. When DU145 cells were cultured in CM from PrSC or cocultured with PrSC, the cells acquired invasive potential, and this invasion was inhibited by an antibody against HGF, but not against TGF-beta1. Native-type HGF production in PrSC was enhanced by some unknown inducer(s) produced by cancer cells. CONCLUSIONS: PrSC-derived HGF enhanced invasive activity of the prostate cancer cell line DU145 through tumor-stromal interaction, wherein DU145 cells secreted some HGF-inducer(s) for PrSC.     

Role of hepatocyte growth factor in invasion of prostate cancer cell lines through tumor-stromal interaction

We examined how prostate stromal cell-derived hepatocyte growth factor (HGF) affects invasion of prostate cancer cells through tumor-stromal interaction. The effects of HGF, various growth factors [transforming growth factor (TGF)-alpha, TGF-beta 1, basic fibroblast growth factor, keratinocyte growth factor, and platelet-derived growth factor], and conditioned medium (CM) from prostate stromal cells (PrSC) on prostate cancer cells (LNCaP, PC-3 and DU145) were determined by collagen gel invesion assay. DU145 cells and PrSC were co-cultured for matrigel invasion chamber assay. LNCaP and PC-3 cells did not respond to any of the factors examined. Invasion of DU145 cells into the collagen gel matrix was induced by HGF and TGF-beta 1, but not by any of the other factors tested. When DU145 cells were cultured in CM from PrSC or co-cultured with PrSC, the cells acquired invasive potential, and this invasion was inhibited by an antibody against HGF, but not against TGF-beta 1. Induction activity of CM from cancer cells to stimulate HGF production by PrSC was studied by ELISA method and Western blotting. Native type HGF production in PrSC was enhanced by some unknown inducer(s) produced by cancer cells. In summary, PrSC-derived HGF enhanced invasive activity of the prostate cancer cell line DU145 through tumor-stromal interaction wherein DU145 cells secreted some HGF-inducer(s) for PrSC.     

Thiazolidinediones reduce endothelial expression of receptors for advanced glycation end products

Advanced glycation end products (AGEs) are critically involved in atherogenesis in diabetes by binding to receptors for AGE (RAGEs) in vascular cells, thus inducing the expression of proinflammatory mediators. In animal models, interruption of the AGE-RAGE interaction reduces lesion size and plaque development. Therefore, limiting RAGE expression might be an intriguing concept to modulate vascular disease in diabetic patients. The present study investigated whether thiazolidinediones (TZDs), antidiabetic agents clinically used to treat patients with type 2 diabetes, might modulate endothelial RAGE expression. Stimulation of human endothelial cells with rosiglitazone or pioglitazone decreased basal as well as tumor necrosis factor-alpha-induced RAGE cell surface and total protein expression. In addition, TZDs reduced RAGE mRNA expression in endothelial cells. These effects on RAGE expression were caused by an inhibition of nuclear factor-kappaB (NF-kappaB) activation at the proximal NF-kappaB site of the RAGE promoter. The functional relevance of reduced RAGE expression was demonstrated by showing that pretreatment of endothelial cells with TZDs decreased AGE- as well as beta-amyloid-induced monocyte chemoattractant protein-1 expression. In conclusion, TZDs reduce RAGE expression in human endothelial cells, thus limiting the cells' susceptibility toward proinflammatory AGE effects. These data provide new insight on how TZDs, in addition to their metabolic effects, might modulate the development of vascular dysfunction in diabetic patients.     

Sharpin蛋白在前列腺癌中的表达及其与Gleason评分、t—PSA关系的研究

目的探讨Sharpin蛋白在人不同前列腺癌细胞株中与前列腺癌组织中的表达及其与Gleason评分、血清PSA的关系。方法采用实时荧光定量PCR法,检测Sharpin在DUl45、PC-3和LNCaP3种常见的前列腺癌细胞株和RWPE．1正常前列腺上皮细胞株中的表达。同时采用免疫组织化学方法检测Sharpin在前列腺增生及前列腺癌组织中的表达,并探讨与临床病理特征的关系。结果Sharpin在3种前列腺癌细胞株中的mRNA水平（1．62±0．31,1．36±0．23,2．1±0．1）要明显高于正常前列腺上皮细胞RWPE-1（0．6±0．11）。免疫组织化学结果示Sharpin在前列腺癌组织中高表达,前列腺癌中的阳性表达率远远高于前列腺增生组织,平均染色得分也要远远高于前列腺增生组织。另外,Sharpin在前列腺癌组织中的表达与患者的Gleason评分和术前血清的t-PSA密切相关,均呈正相关（P〈0．05）。结论Sharpin可能是前列腺癌的肿瘤相关抗原,sharpin的表达可能具有评估前列腺癌患者病情、指导临床治疗方案的指导及判断预后及复发的作用。     

Growth-inhibitory activity of melatonin on human androgen-independent DU 145 prostate cancer cells

BACKGROUND: The pineal hormone melatonin has been shown to exert a direct oncostatic activity on neoplastic cells, particularly from breast cancer. In the present study, we evaluated the effects of melatonin on the proliferation and on the cell cycle distribution of human androgen-independent DU 145 prostate cancer cells. Experiments were also performed to gain insights into the possible mechanism of action of the hormone. METHODS: The effects of melatonin on DU 145 cell proliferation was analyzed by counting the cells by hemocytometer at the end of treatment. The effects of the pineal hormone on cell cycle distribution were evaluated by FACS analysis. RT-PCR studies were performed to detect Mel(1a) and Mel(1b) expression in DU 145 cells. The cellular localization of (125)I-melatonin binding sites was investigated by radioreceptor assay. A commercially available binding-protein assay kit was utilized to evaluate intracellular cAMP levels. RESULTS: Melatonin, in physiological doses, significantly inhibited DU 145 cell proliferation and induced cell cycle withdrawal by accumulating cells in G0/G1 phase. The mRNA for Mel(1a) receptors was found to be expressed in DU 145 cells; however, by radioreceptor assay, no binding sites for (125)I-melatonin could be detected in membrane preparations, suggesting that, in these cells, the level of translation of this mRNA is too low to possibly mediate the antiproliferative action of the hormone. In agreement with this hypothesis, melatonin did not affect forskolin-induced intracellular cAMP accumulation. Binding sites for (125)I-melatonin were found in nuclear extracts of DU 145 cells. CONCLUSIONS: Melatonin exerts a direct oncostatic activity on human androgen-independent prostate cancer cells, by affecting cell cycle progression. This activity seems to be mediated by nuclear, but not by membrane, receptors.