Interactions of human prostatic epithelial cells with bone marrow endothelium: binding and invasion

Prostate cancer shows a propensity to form secondary tumours within the bone marrow. Such tumours are the major cause of mortality in this disease. We have developed an in vitro system to study the binding of prostate epithelial cells to bone marrow endothelium (BME) and stroma (BMS). The metastatic prostate cancer cell line, PC3 (derived from a bone metastasis), was seeded onto confluent layers of BME and its binding characteristics compared to human umbilical vein endothelial cells (HUVEC), lung endothelium (Hs888Lu) and BMS. The PC3 cell line showed significantly increased binding to BME (P< 0.05) compared to endothelium derived from HUVEC and lung or BMS with maximal binding occurring at 1 h. Following pre-incubation with a beta1 integrin antibody PC3 binding to BME was inhibited by 64% (P< 0.001). Antibodies directed against the integrins beta4, alpha2, alpha4, alpha5 and the cellular adhesion molecules P-selectin, CD31, VCAM-1 and sialy Lewis X showed no effect on blocking PC3 binding. Primary prostatic epithelial cells from both malignant (n = 11) and non-malignant tissue (n = 11) also demonstrated equivalent levels of increased adhesion to BME and BMS compared to HUVEC, peaking at 24 h. Further studies examined the invasive ability of prostate epithelial cells in response to bone marrow endothelium using Matrigel invasion chamber assays. In contrast to the previous results, malignant cells showed an increase (1000 fold) in invasive ability, whilst non-malignant prostate epithelia did not respond. We have shown that both malignant and non-malignant prostate epithelial cells can bind at equivalent levels and preferentially to primary human bone marrow endothelium in comparison to controls. However, only malignant prostate epithelia show increased invasive ability in response to BME.     

Prostate cancer cells modulate osteoblast mineralisation and osteoclast differentiation through Id-1

Background:

Id-1 is overexpressed in and correlated with metastatic potential of prostate cancer. The role of Id-1 in this metastatic process was further analysed.

Methods:

Conditioned media from prostate cancer cells, expressing various levels of Id-1, were used to stimulate pre-osteoclast differentiation and osteoblast mineralisation. Downstream effectors of Id-1 were identified. Expressions of Id-1 and its downstream effectors in prostate cancers were studied using immunohistochemistry in a prostate cancer patient cohort (N=110).

Results:

We found that conditioned media from LNCaP prostate cancer cells overexpressing Id-1 had a higher ability to drive osteoclast differentiation and a lower ability to stimulate osteoblast mineralisation than control, whereas conditioned media from PC3 prostate cancer cells with Id-1 knockdown were less able to stimulate osteoclast differentiation. Id-1 was found to negatively regulate TNF-β and this correlation was confirmed in human prostate cancer specimens (P=0.03). Furthermore, addition of recombinant TNF-β to LNCaP Id-1 cell-derived media blocked the effect of Id-1 overexpression on osteoblast mineralisation.

Conclusion:

In prostate cancer cells, the ability of Id-1 to modulate bone cell differentiation favouring metastatic bone disease is partially mediated by TNF-β, and Id-1 could be a potential therapeutic target for prostate cancer to bone metastasis.     

Parathyroid hormone-related protein (PTHrP) is responsible for production of bone metastasis, but not visceral metastasis, by human small cell lung cancer SBC-5 cells in natural killer cell-depleted SCID mice

We previously established an osteolytic bone metastasis model with multiorgan dissemination in natural killer (NK) cell-depleted severe combined immunodeficient (SCID) mice using human small cell lung cancer cells (SBC-5), which highly express the parathyroid hormone-related protein (PTHrP). In our present study, we evaluated the role of PTHrP on bone metastasis by SBC-5 cells using anti-PTHrP neutralizing antibody (Ab). Anti-PTHrP Ab did not affect the proliferation or cytokine production of SBC-5 cells in vitro. Repeated intravenous injection with anti-PTHrP Ab inhibited the formation of bone metastasis in a dose-dependent manner, while the same treatment had no significant effect on the metastasis to visceral organs (lung, liver, kidney and lymph node). In addition, treatment with anti-PTHrP Ab improved the elevated serum calcium level, associated with inhibition of osteolytic bone metastasis, suggesting that anti-PTHrP Ab inhibited bone metastasis via suppression of bone resorption probably by neutralizing PTHrP. These findings suggest that PTHrP is essential for bone metastasis, but not visceral metastasis, by small cell lung cancer SBC-5 cells.     

The prognostic impact of cytokeratin-positive cells in bone marrow of patients with localized prostate cancer

Our study evaluates the prognostic significance of the cytokeratin-positive mononuclear cells (CK+ cells) in the bone marrow (BM) and peripheral blood (PB) as detected by immunocytochemistry in patients with locoregionally confined prostate cancer. BM and PB samples were obtained from 66 newly diagnosed patients with T1-4pN0M0 prostate cancer. All samples were analyzed by standardized immunocytochemical methods (anticytokeratin mononuclear antibody; AE1/AE3) applying a negative immunomagnetic cell enrichment technique. A second sampling was obtained in 60 of the 66 patients >or=2 years after definitive radiotherapy. The median follow-up after high-dose radiotherapy of the patients was 65 months. For the analysis of the postradiotherapy clinical progression-free survival (PFS) treatment, failure was defined as pelvic tumor growth or development of distant metastases. At diagnosis CK+ cells were found in BM in 14 of 66 (21%) prostate cancer patients. This was not associated with an increased risk of progression. On the other hand, the presence of CK+ cells in 12 of 60 (20%) patients at the second BM aspiration was significantly related to a shorterPFS (p = 0.02). In the multivariate analysis, the presence of CK+ cells in the posttreatment BM did not remain as an independent variable of PFS assessment if posttreatment PSA was entered into the analysis. CK+ cells in PB were found in 12% of the patients. After therapy, none of the patients had detectable CK+ cells in PB. The presence of CK+ cells in the posttreatment but not in the pretreatment BM was associated with decreased PFS in patients irradiated for pelvis-confined nonmetastatic prostate cancer. Although this association was not retained in multivariate analysis, our observations indicate that the presence of CK+ cells after local therapy define a group of patients that have a high risk of developing distant metastases.     

Ligand-independent activation of EphA2 by arachidonic acid induces metastasis-like behaviour in prostate cancer cells

Background:

High intake of omega-6 polyunsaturated fatty acids (PUFA) has been associated with clinical progression in prostate cancer (CaP). This study investigates the signalling mechanism by which the omega-6 PUFA arachidonic acid (AA) induces prostatic cellular migration to bone marrow stroma.

Methods:

Western blot analysis of the PC-3, PC3-GFP, DU 145 and LNCaP cells or their lipid raft (LR) components post AA stimulation was conducted in association with assays for adhesion and invasion through the bone marrow endothelial monolayers.

Results:

Arachidonic acid increased transendothelial migration of PC3-GFP cells (adhesion 37%±0.08, P=0.0124; transmigration 270%±0.145, P=0.0008). Akt, Src and focal adhesion kinase (FAK) pathways were induced by AA and integrally involved in transendothelial migration. LR were critical in AA uptake and induced Akt activity. Ephrin receptor A2 (EphA2), localised in LR, is expressed in DU 145 and PC-3 cells. Arachidonic acid induced a rapid increase of EphA2 Akt-dependent/ligand-independent activation, while knockdown of the EphrinA1 ligand decreased AA induced transendothelial migration, with an associated decrease in Src and FAK activity. Arachidonic acid activated Akt in EphA2⁻ LNCaP cells but failed to induce BMEC transendothelial invasion.

Conclusion:

Arachidonic acid induced stimulation of EphA2 in vitro is associated fundamentally with CaP epithelial migration across the endothelial barrier.     

Human prostate cancer bone metastases have an actionable immunosuppressive microenvironment

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GPRC5A facilitates cell proliferation through cell cycle regulation and correlates with bone metastasis in prostate cancer

The prognosis of patients with progressive prostate cancers that are hormone refractory and/or have bone metastasis is poor. Multiple therapeutic targets to improve prostate cancer patient survival have been investigated, including orphan GPCRs. In our study, we identified G Protein-Coupled Receptor Class C Group 5 Member A (GPRC5A) as a candidate therapeutic molecule using integrative gene expression analyses of registered data sets for prostate cancer cell lines. Kaplan–Meier analysis of TCGA data sets revealed that patients who have high GPRC5A expression had significantly shorter overall survival. PC3 prostate cancer cells with CRISPR/Cas9-mediated GPRC5A knockout exhibited significantly reduced cell proliferation both in vitro and in vivo. RNA-seq revealed that GPRC5A KO PC3 cells had dysregulated expression of cell cycle-related genes, leading to cell cycle arrest at the G2/M phase. Furthermore, the registered gene expression profile data set showed that the expression level of GPRC5A in original lesions of prostate cancer patients with bone metastasis was higher than that without bone metastasis. In fact, GPRC5A KO PC3 cells failed to establish bone metastasis in xenograft mice models. In addition, our clinical study revealed that GPRC5A expression levels in prostate cancer patient samples were significantly correlated with bone metastasis as well as the patient's Gleason score (GS). Combined assessment with the immunoreactivity of GPRC5A and GS displayed higher specificity for predicting the occurrence of bone metastasis. Together, our findings indicate that GPRC5A can be a possible therapeutic target and prognostic marker molecule for progressive prostate cancer.     

Endothelin-1 from prostate cancer cells is enhanced by bone contact which blocks osteoclastic bone resorption

The causes for the propensity of metastasized prostate cancer cells to grow in bone and to induce osteoblastic lesions remain unresolved. Co-culture of human prostate cancer cell lines with bone slices was determined to increase the level of endothelin-1 (ET-1) mRNA and its production. ET-1 is an ejaculate protein that also stimulates osteoblasts. Osteoclastic bone resorption was significantly blocked by the presence of androgen-independent prostate cancer cells in a dose-dependent manner as that of synthetic ET-1. The inhibition could be neutralized by specific ET-1 antibody, indicating the association of prostate cancer-derived ET-1 with inhibition of bone resorption. The combined ET-1 activity on osteoclasts and osteoblasts disrupts bone remodelling. ET-1 production is also elevated in the presence of prostate-specific antigen (PSA). ET-1 in turn enhances DNA synthesis of prostate cancer cells. Interactions among cancer cells, bone, ET-1 and PSA may be critical in cancer growth and lesions in bone.     

Influence of omega-6 PUFA arachidonic acid and bone marrow adipocytes on metastatic spread from prostate cancer

Background:

Prostate cancer (CaP) preferentially metastasises to the bone, and we have previously shown that the poly-unsaturated fatty acid (PUFA) arachidonic acid (AA) is a potent stimulator of CaP invasion. Here we present that AA promotes CaP invasion by inducing bone marrow adipocyte formation.

Methods:

Boyden invasion-chamber assays assessed the ability of dietary oils, their PUFA components, and specific PUFA-loaded adipocytes to induce PC-3 invasion. Lipid transfer and metabolism was followed using deuterated AA and Fourier Transform Infrared spectroscopy (FTIR).

Results:

Poly-unsaturated fatty acid constituents, but not their corresponding dietary oils, induced PC-3 invasion. PUFAs induce bone marrow adipocyte (BM-Ad) differentiation with AA inducing higher levels of BM-Ad differentiation, as compared with other PUFAs (3998±514.4 vs 932±265.8; P=0.00002), which stimulated greater PC-3 invasion than free AA (22 408.5±607.4 vs 16 236±313.9; P=0.01111) or adipocytes generated in the presence of other PUFAs. In bone marrow co-culture PC-3 and BM-Ad interactions result in direct uptake and metabolism of AA by PC-3 cells, destruction of the adipocyte and subsequent formation of a bone metastasis.

Conclusion:

The data supports the hypothesis that AA not only promotes CaP invasion, it also prepares the ‘soil'', making it more supportive for implantation and propagation of the migrating metastatic cell.     

Role of proteolytic enzymes in human prostate bone metastasis formation: in vivo and in vitro studies

Prostate cancers ability to invade and grow in bone marrow stroma is thought to be due in part to degradative enzymes. The formation of prostate skeletal metastases have been reproduced in vitro by growing co-cultures of prostatic epithelial cells in bone marrow stroma. Expression of urokinase plasminogen activator, matrix metalloproteinase 1 and 7 by prostatic epithelial cells were identified using immunocytochemistry. Also, in vivo tissue sections from human prostatic bone marrow metastases were stained. To establish the role of these enzymes on colony formation, inhibitory antibodies directed against urokinase plasminogen activator, matrix metalloproteinase 1 and matrix metalloproteinase 7 were added into primary prostatic epithelial cells and bone marrow stroma co-cultures. All prostatic epithelial cell cultures stained positively for matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator. Generally prostatic epithelial cells derived from malignant tissues showed increased staining in comparison to epithelia derived from non-malignant tissue. In agreement with in vitro co-cultures, the in vivo tissue sections of prostate bone marrow metastases showed positive staining for all three enzymes. Inhibition studies demonstrated that blocking matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator function reduced the median epithelial colony area significantly in bone marrow stroma co-cultures in vitro. Using a human ex-vivo model we have shown that matrix metalloproteinase 1, matrix metalloproteinase 7 and urokinase plasminogen activator play an important role in the establishment of prostatic epithelial cells within bone marrow.     

骨髓间充质干细胞源外泌体miR-21-5p 通过下调PHLPP2 促进前列腺癌PC-3 细胞的增殖、迁移和侵袭

目的：探讨骨髓间充质干细胞（bone marrow mesenchymal stem cell,BMSC）来源的外泌体对前列腺癌细胞PC-3 的增殖、迁移和侵袭的影响及其作用机制。方法：采用qPCR检测miR-21-5p 在前列腺癌细胞系中的表达水平。采用电子显微镜观察BMSC分离出的外泌体形态,Western blotting 检测外泌体表面标志物的表达以及上皮间质转化（epithelial-mesenchymal transition,EMT）相关蛋白E-cadherin、N-cadherin 和Vimentin 的表达。采用双荧光素酶报告基因实验检测miR-21-5p 和同源血小板富亮氨酸复重蛋白磷酸酶2（PH domain leucine-rich repeat protein phosphatase 2,PHLPP2）的靶向调控关系。向PC-3 细胞培养液中加入10 μl 的BMSC外泌体悬液（Exo 组）、转染sh-PHLPP2 或antagomiR,CCK-8 和Transwell 实验检测PC-3 细胞增殖和迁移能力。结果：miR-21-5p 在前列腺癌PC-3 细胞系中高表达。成功分离BMSC培养液上清中的外泌体,透射电子显微镜下观察到外泌体典型的囊泡状结构,且表达CD9、CD63 和CD81 等特异性蛋白。Exo组中PC-3 细胞的增殖、侵袭[ （421.34±22.45）vs（200.09±14.22）个,P<0.05]、迁移能力和N-cadherin、Vimentin和miR-21-5p的表达水平均显著高于对照组（均P<0.05）。证实PHLPP2 是miR-21-5p的靶基因。与对照组相比,Exo 组和sh-PHLPP2 组PC-3 细胞中PHLPP2 的表达明显降低（0.66±0.09、0.42±0.05 vs 1.09±0.08,均P<0.01）,细胞增殖、侵袭和迁移[ （87.23±12.67）%、（82.45±10.13）% vs（66.46±9.13）%]能力均显著提高（均P<0.01）,E-cadherin 表达水平显著降低而N-cadherin 和Vimentin 表达水平显著升高（均P<0.05）。结论：miR-21-5p 在前列腺癌PC-3 细胞系中高表达,BMSC外泌体miR-21-5p通过靶向下调PHLPP2提高PC-3 细胞的增殖、迁移和侵袭能力。     

P2Y2 receptor promotes cell invasion and metastasis in prostate cancer cells

Background:

Our previous study demonstrated that extracellular adenosine 5′-triphosphate (ATP) stimulated prostate cancer cell invasion via P2Y receptors. However, the purinergic receptor subtype(s) involved in this process remains unclear. Here we aimed to determine whether P2Y2, one subtype of P2Y receptors, was involved in the invasion and metastasis of prostate cancer cells, and elucidated the underlying mechanism.

Methods:

RNAi was introduced to silence the expression of P2Y2. In vitro invasion and migration assays and in vivo experiments were carried out to examine the role of P2Y2 receptor in cell invasion and metastasis. cDNA microarray was performed to identify the differentially expressed genes downstream of ATP treatment.

Results:

P2Y2 was significantly expressed in the prostate cancer cells. Knockdown of P2Y2 receptor suppressed cell invasion and metastasis in vitro and in vivo. Further experiments identified that ATP could promote IL-8 and Snail expression and inhibit E-cadherin and Claudin-1 expression. Knockdown of P2Y2 receptor affected the expression of these EMT/invasion-related genes in vitro and in vivo.

Conclusion:

P2Y2 receptor promotes cell invasion and metastasis in prostate cancer cells via some EMT/invasion-related genes. Thereby, P2Y2 receptor could be a potential therapeutic target for the treatment of prostate cancer.     

Enhancement of osteoclastogenic activity in osteolytic prostate cancer cells by physical contact with osteoblasts

Background:

The interaction between prostate cancer cells and osteoblasts is critical for the development of bone metastasis. Metastatic cancer cells may physically contact osteoblasts in the bone microenvironment; however, the biological significance of this interaction is not fully understood.

Methods:

Human prostate cancer cells (the osteolytic cell line PC-3 and the osteoblastic cell line MDA-PCa 2b) and human osteoblasts (hFOB1.19) were cocultured under two different conditions (bilayer and contact conditions). Differential gene expression profiles of prostate cancer cells were then investigated using microarray analysis. Differentially expressed genes were analysed using RT–PCR and western blotting, and the effect of anti-cadherin neutralising antibodies on their expression was assayed. The osteoclastogenic activity of cells grown under these different conditions was also investigated using an in vitro assay.

Results:

When PC-3 or MDA-PCa 2b cells were cocultured with hFOB1.19 cells under contact conditions, the expression of eight genes was upregulated and that of one gene was downregulated in PC-3 cells compared with gene expression in bilayer culture. No differentially expressed genes were detected in MDA-PCa 2b cells. Four of the eight upregulated genes (interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), IL-6 and the third component of complement (C3)) have already been reported to participate in osteoclastogenesis. Indeed, a cell lysate of PC-3 cells grown under contact coculture conditions significantly enhanced osteoclastogenesis in vitro (P<0.005). neutralisation of cadherin-11 with a specific antibody inhibited upregulation of COX-2 and C3 mRNA in PC-3 cells. In contrast, neutralisation of N-cadherin induced upregulation of COX-2 mRNA.

Conclusion:

Physical contact between osteolytic prostate cancer cells and osteoblasts may upregulate osteoclastogenesis-related gene expression in prostate cancer cells and enhance osteoclastogenesis. Additionally, cadherin-11 and N-cadherin are involved in this process. These data provide evidence supporting new therapies of prostate cancer bone metastasis that target direct cancer-cell-osteoblast cell–cell contact.     

Upregulation of matrix metalloproteinase-9 in murine 5T33 multiple myeloma cells by interaction with bone marrow endothelial cells

MM is a B-cell malignancy mainly characterized by monoclonal expansion of plasma cells in the BM, presence of paraprotein in serum and occurrence of osteolytic bone lesions. MMPs are a family of proteolytic enzymes that can contribute to cancer growth, invasion, angiogenesis, bone degradation and other processes important in the pathogenesis of MM. We investigated MMP-9 production in the 5T33MM murine model. Expression of MMP-9 protein in supernatant and cell extracts was analyzed by gelatin zymography. The in vitro, stroma-independent variant 5T33MMvt showed no protein expression of MMP-9 in contrast to in vivo growing MM cells, 5T33MMvv. However, when 5T33MMvt cells were injected into naive mice and isolated after tumor take (5T33MMvt-vv), they secreted a significant amount of MMP-9. These results were confirmed by specific staining of cytospins with an anti-MMP-9 antibody. The MMP-9 production by 5T33MMvt-vv cells disappeared when the cells were recultured in vitro. These data demonstrated that upregulation of MMP-9 occurs in vivo and that this process is dependent on the microenvironment. Cocultures of 5T33MMvt cells with STR10 BMECs induced MMP-9 in MM cells, as determined by both gelatin zymography and flow-cytometric analysis. In conclusion, our results demonstrate that MMP-9 production by MM cells is upregulated in vivo by the interaction of MM cells with BMECs.     

Impact of disseminated tumor cells in bone marrow at diagnosis in patients with nonmetastatic prostate cancer treated by definitive radiotherapy

The purpose of this study was to explore whether detection of disseminated tumor cells (DTCs) in bone marrow (BM) of nonmetastatic prostate cancer (PC) was associated with other clinical or histopathological factors at diagnoses or clinical outcome subsequent to definitive radiotherapy (RT). We evaluated BM aspirates from 272 cT(1-4)pN(0)M(0) PC patients by immunocytochemistry employing anticytokeratin antibodies (AE1/AE3). BM-status was compared with clinical and histopathological parameters. Long-term clinical outcome was assessed in 131 of the patients who all had completed definitive RT with or without androgen deprivation (AD), initiating treatment >5 years before cut-off date June 1, 2005. They had at least 1 unfavorable prognostic feature defined as cT(3-4) or Gleason score (GS) >or= 7B or PSA >or= 10 microg/l. Overall death, cause-specific death, distant metastases (DM) as first clinical relapse, local failure as first clinical relapse and biochemical failure were defined as end-points. DTCs were detected in 18% of the patients and were associated with increasing GS (p = 0.04) and percentage of Gleason pattern 4/5 (p = 0.04). The 7-year cumulative risk of DM was 21% for BM-positive patients vs. 6% for BM-negative patients (p = 0.07). In patients receiving RT without AD (n = 75), the 7-year cumulative risk of DM for BM-positive patients was 28% vs. 9% for BM-negative patients (p = 0.03). BM-status did not have impact on other end-points. In conclusion our study shows that presence of DTCs in BM at diagnosis was associated with the histological differentiation of the primary tumor and an increased risk of developing distant metastases after RT.     

非小细胞肺癌骨转移化疗后的骨髓抑制分析

目的：观察晚期非小细胞肺癌骨转移患者化疗后的骨髓抑制程度.方法：将247例晚期非小细胞肺癌患者分为两组,研究组为伴骨转移的患者132例,对照组为无骨转移的患者115例,化疗1周期,进行骨髓抑制和其他不良反应的比较.结果：研究组中化疗后Ⅲ-Ⅳ度白细胞、血小板、红细胞下降的患者比例分别是28.8％、31.1％和20.5％,对照组为15.7％、14.8％和13.0％,差异有统计学意义（P＜0.05）.研究组出现骨髓抑制最严重的平均时间为9天,对照组12天,差异有统计学意义（P＜0.05）.Ⅲ-Ⅳ度恶心、呕吐和流感样症状恶心、呕吐研究组为31.8％、8.3％,对照组为19.1％、1.7％,差异有统计学意义（P＜0.05）.结论：晚期非小细胞肺癌骨转移化疗后更易发生严重的骨髓抑制,且时间提前;恶心、呕吐及流感样症状程度较严重,应注意化疗剂量的调整.     

Novel bone microenvironment model of castration-resistant prostate cancer with chitosan fiber matrix and osteoblasts

The interaction between prostate cancer cells and osteoblasts is essential for the development of bone metastasis. Previously, novel androgen receptor axis-targeted agents (ARATs) were approved for metastatic castration-naïve and non-metastatic castration-resistant prostate cancer (CRPC); both of which are pivotal for investigating the association between the bone microenvironment and tumors. The present study established a novel in vitro 3D microenvironment model that simulated the bone microenvironment of CRPC, and evaluated the drug susceptibility of ARATs and the efficacy of the combination of abiraterone and dutasteride. Green fluorescent protein-transferred C4-2 cells (a CRPC cell line) and red fluorescent protein-transferred human osteoblasts differentiated from human mesenchymal stem cells were co-cultured in chitosan nanofiber matrix-coated culture plates to simulate the 3D scaffold of the bone microenvironment. The growth of C4-2 was quantified using live-cell imaging and the Cell3 iMager duos analysis system. The growth of C4-2 colonies were quantified for a maximum of 30 days. The expression of TGF-β increased and promoted EMT in C4-2 cells co-cultured with osteoblasts, indicating resistance to ARATs. The IC₅₀ of each drug and the combination effect of abiraterone and dutasteride were evaluated using this model. Combination treatment with abiraterone and dutasteride synergistically inhibited the growth of C2-4 colonies compared with individual investigational agents. This could be attributed to the reduction of 3-keto-5α-abiraterone, an androgen receptor agonist. The bone microenvironment model of the present study is unique and useful for evaluating new drug susceptibility testing in prostate cancer cells. This model may help to reveal the unknown mechanisms underlying micro- to clinical bone metastasis in prostate cancer.     

lncRNA GTSE1-AS1在前列腺癌组织中的表达及其对LNCaP细胞增殖与侵袭的影响

目的:探讨长链非编码RNA(long non-coding RNA,lncRNA)GTSE1-AS1在前列腺癌组织中的表达及其影响LNCaP细胞增殖和侵袭的机制.方法:收集2017年11月至2018年12月郑州大学附属洛阳中心医院泌尿外科手术切除的68例前列腺癌患者的癌和癌旁组织标本,以及前列腺癌细胞系LNCaP、PC...     

Acid ceramidase-mediated production of sphingosine 1-phosphate promotes prostate cancer invasion through upregulation of cathepsin B

Invasiveness is one of the key features of aggressive prostate cancer; however, our understanding of the precise mechanisms effecting invasion remains limited. The ceramide hydrolyzing enzyme acid ceramidase (AC), overexpressed in most prostate tumors, causes an aggressive and invasive phenotype through downstream effectors that have not yet been well characterized. Here, we demonstrate that AC, through generation of sphingosine-1-phosphate (S1P), promotes Ets1 nuclear expression and binding to the promoter region of matrix-degrading protease cathepsin B. Through confocal microscopy and flow cytometry, we found that AC overexpression promotes pericellular localization of cathepsin B and its translocation to the outer leaflet of the cell membrane. AC overexpressing cells have an increased abundance of cathepsin B-enriched invasive structures and enhanced ability to invade through a collagen matrix, but not in the presence of an inhibitor of cathepsin B. In human prostate tissues, AC and cathepsin B overexpression were strongly associated and may relate to poor outcome. These results demonstrate a novel pathway by which AC, through S1P, promotes an invasive phenotype in prostate cancer by causing overexpression and secretion of cathepsin B through activation and nuclear expression of Ets1. As prostate cancer prognosis is dramatically worse when invasion has occurred, this study provides critical insight into the progression toward lethal prostate cancer.