Phosphorus metabolite characterization of human prostatic adenocarcinoma in a nude mouse model by 31P magnetic resonance spectroscopy and high pressure liquid chromatography.

A series of experiments were conducted to identify and quantify the phosphorus metabolites of DU 145 xenografts (a human prostatic adenocarcinoma cell line grown in nude mice) using 31P MRS and HPLC. The 31P spectral characteristics of DU 145 xenografts were compared to perfused DU 145 cells and to in situ human prostatic adenocarcinomas. These studies demonstrated that both DU 145 xenografts and perfused DU 145 cells exhibited reduced levels of phosphocreatine relative to spectra of in situ human prostatic adenocarcinomas. Elevated levels of phosphomonesters (PMEs) were observed in 31P spectra of both DU 145 xenografts and in situ human prostatic adenocarcinomas. The major components of the PME resonance of DU 145 xenografts were identified as phosphocholine and phosphoethanolamine. High levels of diphosphodiesters (DPDEs) were consistently observed for both DU 145 xenografts and perfused DU 145 cells, but were absent in 31P spectra in in situ primary human adenocarcinomas. In agreement with spectroscopic results, high pressure liquid chromatographic analyses of human tissue removed at surgery contained insignificant amounts of DPDEs while DU 145 xenografts had high levels of DPDEs consisting mainly of uridine-5'-diphospho-N-acetylgalactosamine (22.4 nmol/mg protein) and uridine-5'-diphospho-N-acetylglucosamine (7.4 nmol/mg protein).     

PIAS3敲低对前列腺癌细胞增殖和凋亡的影响

目的研究PIAS3敲低对人前列腺癌细胞系DU145细胞增殖、细胞周期和凋亡的影响。方法构建PIAS3shRNA表达质粒pSilencer4.1/PIAS3,转染DU145细胞。MTT法检测细胞增殖,流式细胞仪分析细胞周期和凋亡。结果测序证实PIAS3shRNA表达质粒构建成功。转染后DU145细胞PIAS3蛋白表达明显下调。MTT分析显示PIAS3敲低促进细胞增殖,并存在剂量-效应关系。流式细胞术分析显示:PIAS3敲低后S期细胞比例增加,G0/G1期细胞比例减少,凋亡细胞比例减少。结论PIAS3敲低促进体外前列腺癌细胞增殖,抑制其凋亡。     

BPH-1通过分泌前列腺素E2促进前列腺间质细胞芳香化酶的表达

目的：研究前列腺上皮细胞旁分泌对间质细胞芳香化酶表达的影响。方法：用前列腺上皮细胞系（BPH-1, LNCap, DU145, PC3）条件培养液（CM）处理间质细胞，用RT-qPCR和Western blotting检测芳香化酶表达水平。用RT-qPCR和ELISA检测上皮细胞系环氧合酶2（COX-2）的表达及其CM前列腺素E2(PGE2)浓度。用添加COX-2特异性抑制剂NS-398的培养液培养BPH-1，检测其CM和PGE2对间质细胞芳香化酶表达影响。结果：良性前列腺增生上皮细胞系BPH-1 CM能促进间质细胞芳香化酶mRNA和蛋白的表达，而前列腺癌细胞系PC3、DU-145和LNCap对芳香化酶的表达没有影响。BPH-1 COX-2 mRNA表达水平和PGE2分泌水平远高于其它癌细胞系。添加NS-398培养BPH-1的CM，其PGE2浓度明显降低。PGE2可明显诱导间质细胞芳香化酶的表达。结论：BPH-1通过分泌PGE2促进前列腺间质细胞芳香化酶的表达。     

Inhibitory effect of 1-O (2 methoxy) hexadecyl glycerol and phenylbutyrate on the malignant properties of human prostate cancer cells

The ability of the naturally occurring ether lipid, 1-O (2 methoxy) hexadecyl glycerol (MHG), and phenylbutyrate (BP) to inhibit cellular proliferation, anchorage-independent growth and cellular invasion in the human prostate cancer LnCap and DU145 cells was determined. Both MHG and PB inhibited the malignant properties of these prostate cancer cells. The concentrations required to achieve similar inhibitory effect, however, were significantly different for these two agents. MHG inhibited cell growth with equal potency in these cell lines with an IC-50 value of 93 μM for LnCap, and 97 μM for DU145. The IC-50 values for PB were 1.3 mM and 7.3 mM, respectively, for LnCap and DU145 cells. Both MHG and PB (IC-50 concentrations) inhibited the anchorage-independent growth and cellular invasion in these cells. Over 50% inhibition of anchorage-independent growth was achieved for both LnCap and DU145 cells by PB, while a lesser degree of inhibition was achieved with MHG. Both MHG- and PB-treated cells showed a reduced propensity to invade matrigels. Invasion of PB-treated LnCap and DU145 cells was reduced, respectively, by approximate 41 and 30% when compared to untreated control cells, while invasion of MHG-treated LnCap and DU145 cells was reduced to a lesser extent. Because differentiation-inducing agents may possess chemopreventive properties, the use of naturally occurring MHG and nontoxic PB in the chemoprevention of malignant diseases warrants further investigation. This revised version was published online in July 2006 with corrections to the Cover Date.     

The reciprocal interactions between astrocytes and prostate cancer cells represent an early event associated with brain metastasis

Tumor establishment, growth, and survival are supported by interactions with microenvironment components. Here, we investigated whether the interactions between prostate cancer cells and cortical astrocytes are associated to a potential role for astrocytes in tumor establishment. We demonstrate that astrocytes interact in vitro with prostatic cancers cells derived from different metastatic sites. Astrocytes and their secreted extracellular matrix, stimulate DU145 cell (a brain-derived prostate tumor cell line) proliferation while inhibiting cell death and modulating the expression of several genes related to prostate cancer progression, suggesting the activation of EMT process in these cells. In contrast, DU145 cells and their conditioned medium inhibited cell proliferation and induced cell death of astrocytes. On the other hand, the astrocytes were unable to significantly induce an increment of LNCaP cell (a lymph node-derived prostate tumor cell line) proliferative activity. In addition, LNCaP cells were also unable to induce cell death of astrocytes. Thus, we believe that DU145 cells, but not LNCaP cells, present an even more aggressive behavior when interacting with astrocytes. These results provide an important contribution to the elucidation of the cellular mechanisms involved in the brain microenvironment colonization.     

Comparison of the malignant phenotype and genotype of the human androgen-independent cell line DU 145 and a subline derived from metastasis after orthotopic implantation in nude mice

To investigate the potential genetic changes underlying the progression of human hormone-resistant prostate cancer, we related chromosomal alterations of the DU 145 cell line and a subline isolated form a metastasis in an orthotopic model to tumorigenicity, metastasis and chemoresistance. In 15 mice 1 x 10(5) DU 145 cells were injected into the dorsal prostate. From a resulting paraaortic lymphnode metastasis, we isolated a subline (DU 145 MN1), which was injected into 15 nude mice. The sulforhodamine B (SRB) assay was used to analyze cell doubling time and the IC(50) of cisplatin and 5-fluorouracil for both cell lines. Cytogenetic characterization was performed with conventional karyotype analysis and fluorescence in situ hybridization (FISH). After orthotopic implantation of DU 145 cells tumorigenicity was 100% whereas only 2 mice revealed lymphnode metastases. In contrast, the take rate after implantation of DU 145 MN1 was 100%, with lymphnode metastases in 7 mice. The SRB assay revealed a 8-fold increased IC(50) for cisplatin and a 2.5-fold increase for 5-FU in DU 145 MN1 as compared to DU 145 cells. There was gain of a chromosome 8 and only two copies of chromosome 17 in the DU 145 MN1 cells as compared to the parental cell line. The emergence of an i(9)(q10) in addition to two normal chromosome 9 homologues in the DU 145 MN1 cell line was confirmed by FISH using a chromosome 9-specific painting probe. In summary, clonal evolution of the chromosomal changes following repeated orthotopic implantation, may assist in locating the genes involved in the progression and chemoresistance of human hormone-resistant prostate cancer.     

Isolation of human prostate cancer cell reactive antibodies using phage display technology

Here we describe a phage display strategy for the selection of rabbit monoclonal antibodies that recognize cell surface tumor-associated antigens expressed in prostate cancer. Two immune rabbit/human chimeric Fab libraries were displayed on phage and used to search for tumor-associated antigens by panning on DU145 human prostate cancer cells. For this, we developed a novel whole-cell panning protocol with two negative selection steps designed to remove antibodies reacting with common antigens. After three rounds of subtractive panning, a majority of clones bound to DU145 cells as detected by flow cytometry. Among these, we identified several clones that bound selectively to DU145 cells but not to primary human prostate epithelial cell line PrEC. In summary, our work demonstrates the potential of immune rabbit antibody libraries for target discovery in general and the identification of cell surface tumor-associated antigens in particular.     

SH003 induces apoptosis of DU145 prostate cancer cells by inhibiting ERK-involved pathway

Background

Herbal medicines have been used in cancer treatment, with many exhibiting favorable side effect and toxicity profiles compared with conventional chemotherapeutic agents. SH003 is a novel extract from Astragalus membranaceus, Angelica gigas, and Trichosanthes Kirilowii Maximowicz combined at a 1:1:1 ratio that impairs the growth of breast cancer cells. This study investigates anti-cancer effects of SH003 in prostate cancer cells.

Methods

SH003 extract in 30% ethanol was used to treat the prostate cancer cell lines DU145, LNCaP, and PC-3. Cell viability was determined by MTT and BrdU incorporation assays. Next, apoptotic cell death was determined by Annexin V and 7-AAD double staining methods. Western blotting was conducted to measure protein expression levels of components of cell death and signaling pathways. Intracellular reactive oxygen species (ROS) levels were measured using H₂DCF-DA. Plasmid-mediated ERK2 overexpression in DU145 cells was used to examine the effect of rescuing ERK2 function. Results were analyzed using the Student’s t-test and P-values?<?0.05 were considered to indicate statistically-significant differences.

Results

Our data demonstrate that SH003 induced apoptosis in DU145 prostate cancer cells by inhibiting ERK signaling. SH003 induced apoptosis of prostate cancer cells in dose-dependent manner, which was independent of androgen dependency. SH003 also increased intracellular ROS levels but this is not associated with its pro-apoptotic effects. SH003 inhibited phosphorylation of Ras/Raf1/MEK/ERK/p90RSK in androgen-independent DU145 cells, but not androgen-dependent LNCaP and PC-3 cells. Moreover, ERK2 overexpression rescued SH003-induced apoptosis in DU145 cells.

Conclusions

SH003 induces apoptotic cell death of DU145 prostate cancer cells by inhibiting ERK2-mediated signaling.

     

NEU3对人前列腺癌DU145细胞生物学行为的影响

目的:探讨神经氨酸酶3(NEU3)与人前列腺癌DU145细胞活力、侵袭和凋亡的关系,并探讨其分子机制。方法:体外培养人前列腺癌DU145细胞,并分为空白对照组和处理组,处理组再分别给予神经氨酸酶活性抑制剂DANA处理和RNA干扰靶向沉默NEU3,采用CCK-8法检测细胞的活力;Transwell法检测细胞侵袭能力;q PCR法检测2种处理方式对凋亡抑制蛋白Bcl-2 mRNA水平的影响;Western blot法检测2种处理方式对NEU3、基质金属蛋白酶2(MMP2)和Bcl-2表达的影响;流式细胞术检测细胞凋亡水平。结果:与空白对照组相比,DANA处理后前列腺癌细胞的NEU3表达无明显变化,细胞活力增强,MMP2蛋白表达减少,侵袭力减弱,凋亡无明显变化,Bcl-2的mRNA和蛋白表达减少(P 0.05);NEU3沉默后NEU3蛋白表达减少,细胞活力增强,MMP2蛋白表达和细胞侵袭力无明显变化,凋亡能力增强,Bcl-2的mRNA和蛋白表达均下降(P 0.05)。结论:抑制NEU3可以减弱人前列腺癌DU145细胞活力,增强细胞凋亡能力,但对侵袭能力无明显影响。     

Lymphatic endothelial cells actively regulate prostate cancer cell invasion

Lymphatic vessels serve as the primary route for metastatic spread to lymph nodes. However, it is not clear how interactions between cancer cells and lymphatic endothelial cells (LECs), especially within hypoxic microenvironments, affect the invasion of cancer cells. Here, using an MR compatible cell perfusion assay, we investigated the role of LEC–prostate cancer (PCa) cell interaction in the invasion and degradation of the extracellular matrix (ECM) by two human PCa cell lines, PC‐3 and DU‐145, under normoxia and hypoxia, and determined the metabolic changes that occurred under these conditions. We observed a significant increase in the invasion of ECM by invasive PC‐3 cells, but not poorly invasive DU‐145 cells when human dermal lymphatic microvascular endothelial cells (HMVEC‐dlys) were present. Enhanced degradation of ECM by PC‐3 cells in the presence of HMVEC‐dlys identified interactions between HMVEC‐dlys and PCa cells influencing cancer cell invasion. The enhanced ECM degradation was partly attributed to increased MMP‐9 enzymatic activity in PC‐3 cells when HMVEC‐dlys were in close proximity. Significantly higher uPAR and MMP‐9 expression levels observed in PC‐3 cells compared to DU‐145 cells may be one mechanism for increased invasion and degradation of matrigel by these cells irrespective of the presence of HMVEC‐dlys. Hypoxia significantly decreased invasion by PC‐3 cells, but this decrease was significantly attenuated when HMVEC‐dlys were present. Significantly higher phosphocholine was observed in invasive PC‐3 cells, while higher glycerophosphocholine was observed in DU‐145 cells. These metabolites were not altered in the presence of HMVEC‐dlys. Significantly increased lipid levels and lipid droplets were observed in PC‐3 and DU‐145 cells under hypoxia reflecting an adaptive survival response to oxidative stress. These results suggest that in vivo, invasive cells in or near lymphatic endothelial cells are likely to be more invasive and degrade the ECM to influence the metastatic cascade. Copyright © 2016 John Wiley & Sons, Ltd.     

Slowing tumorigenic progression in TRAMP mice and prostatic carcinoma cell lines using natural anti-oxidant from spinach,NAO--a comparative study of three anti-oxidants

The TRAMP model and human prostatic cancer (PCA) cell lines DU145 and PC3 are useful forchemopreventive studies. We compared the efficacy of 3 anti-oxidants [a water-soluble natural anti-oxidant. NAO (200 mg/kg). found in spinach leaves; epigallocatechin-3 gallate, EGCG (200 mg/kg), a major green tea polyphenol; and N-acetylcysteine, NAC (125 mg/kg)] plus vehicle in slowing spontaneous tumorigenic progression in TRAMP and wild-type male mice. Sacrifices occurred on weeks 5, 9, and 13. Prostatic histopathology and oxidative-stress blood markers were evaluated. Hyperplasias were ranked by a combination of severity grade and distribution (focal, multifocal, and diffuse). The effectivity of each tested compound in reducing the severity/focalness of hyperplasia varied from lobe to lobe. NAO exerted a significant effect on the dorsal and lateral lobes; NAC, on the anterior and ventral lobes, and EGCG, on the ventral lobe. When the most severe hyperplasia in all 4 lobes of TRAMPs was evaluated, only NAO reduced hyperplasia at weeks 9 and 13. Plasma peroxide levels in TRAMPs were reduced following oral administration of NAO or NAC for 13 weeks; EGCG only slightly reduced these levels. In NAO-treated DU 145 and PC3 PCA cells, inhibition of cellular proliferation occurred in a dose-dependent manner, increasing numbers of G1 cells and reducing ROS levels. The anti-oxidative and antiproliferative properties of NAO may explain its efficacy in slowing the spontaneous prostatic carcinogenic process in the TRAMP and its effects in the cell lines.     

The significance of LMO2 expression in the progression of prostate cancer

LIM domain only 2 (LMO2) proteins are important regulators in determining cell fate and controlling cell growth and differentiation. This study has investigated LMO2 expression in human prostatic tissue specimens, prostate cancer cell lines, and xenografts; and has assessed the possible role and mechanism of LMO2 in prostate carcinogenesis. Immunohistochemical analysis on a tissue microarray consisting of 91 human prostate specimens, including normal, prostatic hyperplasia, high-grade prostatic intraepithelial neoplasia, and invasive carcinoma, revealed that overexpression of LMO2 was significantly associated with advanced tumour stage, as measured by Gleason score (p = 0.012), as well as with the development of distant metastasis (p = 0.018). These data were supported by quantitative real-time PCR experiments, where LMO2 mRNA levels were found to be significantly higher in prostate tumour specimen than in normal epithelium (p = 0.037). The expression of LMO2 in cell lines and xenografts representing androgen-dependent (AD) and androgen-independent (AI) prostate cancer stages was further studied. Consistent with the in vivo data, LMO2 mRNA and protein were found to be overexpressed in the more aggressive AI cells (PC3, DU145, and AI CWR22 xenografts) compared with less aggressive AD cells (LNCaP and AD CWR22 xenografts). Furthermore, stable introduction of LMO2 into LNCaP cells conferred enhanced cell motility and invasiveness in vitro, accompanied by down-regulation of E-cadherin expression. Taken together, these findings provide the first evidence to support the hypothesis that LMO2 may play an important role in prostate cancer progression, possibly via repression of E-cadherin expression.     

The effect of dexamethasone on human mucin 1 expression and antibody-dependent complement sensitivity in a prostate cancer cell line in vitro and in vivo

Dexamethasone has been shown to up-regulate human mucin 1 (MUC1) expression in certain types of cancer cell lines in vitro, suggesting that this gluocorticoid may enhance MUC1-based immunotherapies. Here we investigated the effect of dexamethasone on MUC1 expression in the DU145 human prostate cancer cell line in terms of antibody-mediated complement-dependent cell lysis. Cells treated with 1 x 10-8 m dexamethasone in vitro expressed maximal levels of MUC1 after 6 days, with an approximately 3-fold increase over MUC1 levels on untreated cells. DU145 cells were highly resistant to lysis by anti-MUC1 antibody and complement, and their susceptibility to antibody and complement was unaffected by dexamethasone treatment. However, dexamethasone also induced expression of the complement inhibitor decay accelerating factor (DAF) on DU145 cells. Blocking or overcoming the function of DAF resulted in enhanced complement-dependent lysis of dexamethasone-treated cells with anti-MUC1 antibodies, indicating that the failure of dexamethasone to enhance the complement susceptibility of DU145 cells was caused by the up-regulated expression of DAF. We also investigated MUC1 expression in vivo and found that MUC1 expression was significantly up-regulated on tumour cells isolated from immune-deficient mice that had been injected with dexamethasone. However, in contrast to in vitro data, there was no difference between the levels of DAF expressed on tumour-derived DU145 cells isolated from either phosphate buffered saline (PBS)-treated or dexamethasone-treated mice, and tumour cells isolated from dexamethasone-treated mice were more sensitive to complement-mediated lysis. In the broad context of immunotherapy, the in vivo data support the use of dexamethasone as an adjunct treatment. Up-regulated DAF expression would not be a favourable outcome of dexamethasone treatment in terms of complement-dependent antibody therapy, but the in vivo data caution against extrapolation of in vitro data with regard to the modulation of complement inhibitors reported here and elsewhere.     

ENDOD1在前列腺癌组织及细胞中的表达及意义

目的:观察比较核酸内切酶结构域内含蛋白1(endonuclease domain containing1,ENDOD1)在良性前列腺增生和前列腺癌组织中的表达差异;筛选存在ENDOD1特异性低表达的前列腺癌细胞系,继而通过调控该细胞ENDOD1蛋白表达,研究其在前列腺癌细胞中的生物学功能,初步探索ENDOD1基因与前列腺癌发生、进展的联系。方法:利用免疫组化SP法检测20例良性前列腺增生和21例前列腺癌术后标本组织中ENDOD1表达情况;利用RT-qPCR和Western blot方法观察ENDOD1的mRNA和蛋白在前列腺正常上皮细胞和不同类型前列腺癌细胞中的表达差异,筛选出特异性低表达细胞系;构建pCMV-N-Flag-ENDOD1重组质粒,转染前列腺癌细胞株,过表达ENDOD1蛋白,通过MTT法测定调控前后前列腺癌细胞活力的变化,流式细胞术检测细胞周期和凋亡,Transwell实验评价肿瘤细胞迁移和侵袭能力的改变。结果:免疫组化评分的方差分析结果显示ENDOD1表达与前列腺癌Gleason评分呈负性关联;RT-qPCR和Western blot实验结果表明ENDOD1在雄激素非依赖性前列腺癌细胞系PC3和DU145中存在着特异性低表达(P0.05)。同时,MTT实验显示,在DU145细胞中,过表达ENDOD1肿瘤细胞活力显著下降(P0.05);而流式细胞术检测结果表明过表达ENDOD1能够使DU145细胞周期停滞在G_0/G_1期,但细胞凋亡率无明显差异。此外,在Transwell实验中,过表达ENDOD1的DU145细胞迁移和侵袭能力明显下降(P0.05)。结论:ENDOD1在Gleason评分越高的前列腺癌中表达越低,同时在雄激素非依赖性前列腺癌细胞系存在着特异性低表达;而过表达ENDOD1能明显抑制雄激素非依赖性前列腺癌细胞的生长、迁移和侵袭能力。     

Spatial composition of prostate cancer spheroids in mixed and static cultures

Aggregation of neoplastic cells produces multicellular spheroids resembling micrometastases. The objective of this study was to investigate the effects of mixing culture medium on the spatial composition of spheroids prepared from well (LNCaP) and poorly (DU 145) differentiated human prostate cancer cells. Spheroids were cultured in a mixed suspension within a high-aspect rotating wall vessel and static liquid-overlay plate. Results from this study demonstrate that mixed cultures consistently manifested differences in morphology and composition between DU 145 and LNCaP spheroids. For example, 40 +/- 12% of DU 145 cells were Ki-67 positive 100 microm from the surface within mixed spheroids versus 0% for LNCaP cells; there was no significant difference in this spatial profile for static cultures. The results suggest that poorly differentiated spheroids may be more likely to experience a change in composition from mixing culture medium than well-differentiated spheroids, due to low tissue density. Immunostaining for P-glycoprotein is representative of this trend; average staining intensity increased 50% for DU 145 spheroids on mixing but was unchanged for LNCaP spheroids. The effects of mixing on spheroid composition were attributed to faster interstitial mass transport. Applications include drug development and delivery, as well as basic research on drug action and resistance.     

Culture and co-culture of DU145 prostate carcinoma,osteoblasts and HT-29 colon carcinoma cells on a fabricated type III collagen matrix

DU145 prostate carcinoma cells cultured on type III collagen possessed a highly migratory potential which was twice as much as HT-29 colon carcinoma cells. Prior to attachment to collagen, DU145 cells were highly reactive for fibronectin and after attachment clear zones between cells and collagen suggested protease activity. HT-29 cells attached to type III collagen forming dome-like polyps, however, tight and/or gap junctions were not observed. hFob osteoblasts were co-cultured with DU145 to establish a prostate cancer-collagen matrix barrier-bone cell metastasis model. Osteoblasts maintained their differentiated osteoblastic characteristics on one side of the collagen barrier, demonstrating high alkaline phosphatase, osteocalcin and insulin growth factor (IGF) activities. hFob cell growth was prominent adjacent to demineralized bone matrix particles (BMPs) embedded in type III collagen. The collagen matrix was deteriorated on the DU145 side of the collagen barrier. The DU145-collagen III-hFob model will allow an evaluation of the influence of the matrix on prostate cancer-bone cell interaction and regulation by growth factors.     

The use of multicolor fluorescence technologies in the characterization of prostate carcinoma cell lines: a comparison of multiplex fluorescence in situ hybridization and spectral karyotyping data

Recent studies have identified several chromosome regions that are altered in primary prostate cancer and prostatic carcinoma cell lines. These targeted regions may harbor genes involved in tumor suppression. We used multiplex fluorescence in situ hybridization (M-FISH) to screen for genetic rearrangements in four prostate cancer cell lines, LNCaP, LNCaP.FCG, DU145, and PC3, and compared our results with those recently obtained using spectral karyotyping (SKY). A number of differences was noted between abnormalities characterized by SKY and M-FISH, suggesting variation in karyotype evolution and characterization by these two methodologies. M-FISH analysis showed that hormone-resistant cell lines (DU145 and PC3) contained many genetic alterations (> or =15 per cell), suggesting high levels of genetic instability in hormone-refractory prostate cancer. Most chromosome regions previously implicated in prostate cancer were altered in one or more of these cell lines. Several specific chromosome aberrations were also detected, including a del(4)(p14) and a del(6)(q21) in the hormone-insensitive cell lines, a t(1;15)(p?;q?) in LNCaP, LNCaP, and PC3, and a i(5p) in LNCaP.FCG, DU145, and PC3. These clonal chromosome abnormalities may pinpoint gene loci associated with prostate tumourigenesis, cancer progression, and hormone sensitivity.     

A Rare,Human Prostate Oncocyte Cell Originates from the Prostatic Carcinoma (DU145) Cell Line

Abstract

DU145 human prostate carcinoma cells are typically poorly differentiated and contain only scantily distributed organelles. However, among numerous tumor cells randomly examined by electron microscopy out of in vitro cultivation, a peculiar, rare oncocyte-like cell type has been observed whose nucleus appears to be of small dimension and with a cytoplasm almost entirely filled with often distorted mitochondria. A few small, dispersed lysosomal bodies, small cisterns of the endoplasmic reticulum and a few glycogen patches can be found among highly osmiophilic contrasted, cytosolic spaces filled by innumerable ribonucleoproteins. The excessive population of mitochondria may have arisen from a more populated tumor cell type wherein the altered mitochondria are found to appear burgeoning into a spherical-like size progeny crowding the tumor cells. Literature cited between 1950 and the present suggests that this rare, oncocytic, benign prostatic tumor cell type is likely appear epigenetically, stemming from an original secretory cell, which is confirmed by the origin of the cell line originally maintained as cell line out of a brain metastatic, adenocarcinoma niche.     

Ceramide induces cell death in the human prostatic carcinoma cell lines PC3 and DU145 but does not seem to be involved in Fas-mediated apoptosis

Treatment of cells with synthetic C2-ceramide has been reported to induce apoptosis in several cell systems, and endogenously formed ceramide has been proposed to act as a second messenger, activating signaling pathways which contribute to the execution of apoptotic cell death after Fas ligation or tumor necrosis factor receptor-1 ligation. In this study, we examined the effect of exogenously administered C2-ceramide on the human prostatic carcinoma cell lines PC3 (Fas-sensitive) and DU145 (Fas-resistant). In both cell lines, C2-ceramide induced cell death in a dose-dependent manner, whereas a structural analog, C2-dihydroceramide, did not. The pan-caspase inhibitor zVAD-fmk did not prevent C2-ceramide-induced cell death but did prevent C2-ceramide-induced DNA fragmentation, indicating that apoptotic and non-apoptotic mechanisms are involved in C2-ceramide-induced death. Interestingly, cycloheximide prevented C2-ceramide-induced DNA fragmentation, indicating that ceramide-induced apoptosis in PC3 and DU145 requires new protein synthesis. In addition, because cycloheximide converts Fas-resistant DU145 to Fas-sensitive as assessed by DNA fragmentation, ceramide does not seem to play a major role in the Fas-mediated pathway in this cell line. We also determined the levels of endogenous sphingomyelin after Fas ligation in PC3. No decrease of sphingomyelin levels could be detected after Fas activation. We conclude that sphingomyelinase-generated ceramide does not play a role in Fas-mediated apoptosis in PC3, and that there are fundamental differences in the mechanisms of cell death induced by C2-ceramide and Fas ligation.