Down.regulation of E.cadherin enhances prostate cancer chemoresistance via Notch signaling

Background:The chemoresistance of prostate cancer(PCa)is invariably associated with the aggressiveness and metastasis of this disease.New emerging evidence indicates that the epithelial-to-mesenchymal transition(EMT)may play pivotal roles in the development of chemoresistance and metastasis.As a hallmark of EMT,E-cadherin is suggested to be a key marker in the development of chemoresistance.However,the molecular mechanisms underlying PCa chemoresistance remain unclear.The current study aimed to explore the association between EMT and chemoresistance in PCa as well as whether changing the expression of E-cadherin would affect PCa chemoresistance.Methods:Parental PC3 and DU145 cells and their chemoresistant PC3-Tx R and DU145-Tx R cells were analyzed.PC3-Tx R and DU145-Tx R cells were transfected with E-cadherin-expressing lentivirus to overexpress E-cadherin;PC3 and DU145 cells were transfected with small interfering RNA to silence E-cadherin.Changes of EMT phenotype-related markers and signaling pathways were assessed by Western blotting and quantitative real-time polymerase chain reaction.Tumor cell migration,invasion,and colony formation were then evaluated by wound healing,transwell,and colony formation assays,respectively.The drug sensitivity was evaluated using MTS assay.Results:Chemoresistant PC3-Tx R and DU145-Tx R cells exhibited an invasive and metastatic phenotype that associated with EMT,including the down-regulation of E-cadherin and up-regulation of Vimentin,Snail,and N-cadherin,comparing with that of parental PC3 and DU145 cells.When E-cadherin was overexpressed in PC3-Tx R and DU145-Tx R cells,the expression of Vimentin and Claudin-1 was down-regulated,and tumor cell migration and invasion were inhibited.In particular,the sensitivity to paclitaxel was reactivated in E-cadherin-overexpressing PC3-Tx R and DU145-Tx R cells.When E-cadherin expression was silenced in parental PC3 and DU145 cells,the expression of Vimentin and Snail was up-regulated,and,particularly,the sensitivity to paclitaxel was decreased.Interestingly,Notch-1 expression was up-regulated in PC3-Tx R and DU145-Tx R cells,whereas the E-cadherin expression was down-regulated in these cells comparing with their parental cells.The use ofγ-secretase inhibitor,a Notch signaling pathway inhibitor,significantly increased the sensitivity of chemoresistant cells to paclitaxel.Conclusion:The down-regulation of E-cadherin enhances PCa chemoresistance via Notch signaling,and inhibiting the Notch signaling pathway may reverse PCa chemoresistance.

Wnt3a:functions and implications in cancer

Wnt3a,one of Wnt family members,plays key roles in regulating pleiotropic cellular functions,including self-renewal,proliferation,differentiation,and motility.Accumulating evidence has suggested that Wnt3 a promotes or suppresses tumor progression via the canonical Wnt signaling pathway depending on cancer type.In addition,the roles of Wnt3 a signaling can be inhibited by multiple proteins or chemicals.Herein,we summarize the latest findings on Wnt3 a as an important therapeutic target in cancer.

α-Vitamin E derivative, RRR-α-tocopheryloxybutyric acid inhibits the proliferation of prostate cancer cells

Aim： To investigate the activity of RRR-α-tocopheryloxybutyric acid （TOB）, an ether analog of RRR-α-tocopheryl succinate （VES）, in prostate cancer cells. Methods： VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rvl cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis. Results： The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen （PSA） at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor （VDR） expression increased after the addition of TOB. Conclusion： Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.

Neural regulation of sexual function in men

Male sexual response is controlled by a series of neurally mediated phenomena regulating libido, motivation, arousal and genital responses such as penile erection and ejaculation. These neural events that occur in a hormonally defined milieu involve different neurophysiological, neurochemical, and neuropsychological parameters controlled by central mechanisms, spinal reflexes and peripheral nervous system. Epidemiologic studies have suggested the high prevalence of male sexual dysfunction worldwide with significant impact on the quality of life of patients suffering from this problem. The incidence of sexual dysfunction is particularly high among men with neurologic disorders. Sexual dysfunction in men, such as loss of sexual desire, erectile dysfunction(ED), changes in arousal, and disturbances in orgasm and ejaculation may involve organic causes, psychological problems, or both. Organic male sexual disorders include a wide variety of neurologic, vasculogenic, neurovascular or hormonal factors that interfere with libido,erection, ejaculation and orgasm. Neurogenic sexual dysfunction may result from a specific neurologic problem or it could be the presenting symptom of a developing neurologic disease. Neurologic ED could result from complications of chronic neurologic disorders, trauma, surgical injury or iatrogenic causes. These etiologic factors and the underlying pathophysiologic conditions could overlap, which should be considered when making a diagnosis and selecting a treatment. A detailed history of physical examination, neurologic disorders, as well as any past history of psychological and psychiatric disturbances, and a thorough neurological examination will provide better understanding of the underlying causes of neurogenic sexual dysfunction. In patients with spinal cord injury, the location of the lesion and the time of onset of injury should be determined. Therapeutic strategies against erectile dysfunction are initiated with the least invasive options using the phosphodiesterase inhibitors. When oral medication options are exhausted, intraurethral and intracavernosal therapies and ultimately vacuum constriction devices and penile implants are considered. Recent basic research has suggested the potential role of stem cell-based therapeutic strategies to protect penile neural integrity and reverse cavernosal neurodegeneration in experimental models. Further insight into the central, spinal and peripheral neural mechanisms of male sexual response may help precise diagnosis and better management of neurogenic sexual dysfunction in men.

Metformin targets multiple signaling pathways in cancer

Metformin,an inexpensive and well-tolerated oral agent commonly used in the first-line treatment of type 2 diabetes,has become the focus of intense research as a candidate anticancer agent.Here,we discuss the potential of metformin in cancer therapeutics,particularly its functions in multiple signaling pathways,including AMP-activated protein kinase,mammalian target of rapamycin,insulin-like growth factor,c-Jun N-terminal kinase/mitogen-activated protein kinase(p38 MARK),human epidermal growth factor receptor-2,and nuclear factor kappaB pathways.In addition,cutting-edge targeting of cancer stem cells by metformin is summarized.

Reduced prostate branching morphogenes,s in stromal fibroblast, but not in epithelial, estrogen receptor a knockout mice

Early studies suggested that estrogen receptor alpha （ERa） is involved in estrogen-mediated imprinting effects in prostate development. We recently reported a more complete ERa knockout （KO） mouse model via mating β-actin Cre transgenic mice with floxed ERa mice. These ACTB-ERaKO male mice showed defects in prostatic branching morphogenesis, which demonstrates that ERa is necessary to maintain proliferative events in the prostate. However, within which prostate cell type ERa exerts those important functions remains to be elucidated. To address this, we have bred floxed ERa mice with either fibroblast-specific protein （FSP）-Cre or probasin-Cre transgenic mice to generate a mouse model that has deleted ERa gene in either stromal fibroblast （FSP-ERaKO） or epithelial （pes-ERaKO） prostate cells. We found that circulating testosterone and fertility were not altered in FSP.ERaKO and pes-ERaKO male mice. Prostates of FSP-ERaKO mice have less branching morphogenesis compared to that of wild-type littermates. Further analyses indicated that loss of stromal ERa leads to increased stromal apoptosis, reduced expression of insulin-likegrowth factor-1 （IGF-1） and FGFIO, and increased expression of BMP4. Collectively, we have established the first in vivo prostate stromal and epithelial selective ERaKO mouse models and the results from these mice indicated that stromal fibroblast ERa plays important roles in prostatic branching morphogenesis via a paracrine fashion. Selective deletion of the ERa gene in mouse prostate epithelial cells by probasin-Cre does not affect the regular prostate development and homeostasis.

Expression of hypoxia-inducible factor 1α in human normal, benign, and malignant prostate tissue

Objective To investigate hypoxia-inducible factor 1α (HIF-1α) protein expression in normal prostates (NP), benign prostatic glandular hyperplasia (BPH), and prostate adenocarcinoma (Pca).Methods HIF-1α protein expression was determined by immunohistochemistry in formalin-fixed and paraffin-embedded specimens obtained from 13 cases of NP, 28 cases of BPH, and 34 cases of Pca. In cases of Pca, the relationship between HIF-1α protein expression and certain clinicopathological factors, such as clinicopathologic stage and Gleason score, was evaluated. Results NP manifested no immunoreactivity, whereas Pca and BPH showed significantly increased HIF-1α protein expression. A significantly higher expression was observed in Pca specimens compared with BPH samples. In Pca, no significant relationship between HIF-1α protein expression and clinicopathological factors was found. Conclusion Our findings of increased HIF-1α protein expression in BPH and Pca specimens suggests the potential role of this protein in BPH and Pca.

E-cadherin表达下调激活Notch信号通路增强前列腺癌化疗耐药的机制研究

背景与目的前列腺癌(prostate cancer,PCa)化疗耐药与其侵袭性和转移性密切相关。最新研究显示上皮细胞–间充质转化(epithelial-to-mesenchymal transition,EMT)可能在前列腺癌化疗耐药和转移中发挥重要作用。因此,作为EMT的标志物,E-cadherin被认为有可能与肿瘤化疗耐药有重要关系。然而,PCa化疗耐药的分子机制尚不清楚。本研究旨在探讨EMT与PCa化疗耐药的关系,以及E-cadherin表达变化是否影响PCa化疗耐药。方法以亲代PC3和DU145细胞及其化疗耐药PC3-TxR和DU145-TxR细胞作为研究对象。用E-cadherin过表达的慢病毒感染PC3-TxR和DU145-TxR细胞,使E-cadherin过表达;同时,用小干扰RNA转染PC3和DU145细胞,使E-cadherin表达沉默。采用蛋白免疫印迹和实时定量聚合酶链反应分析EMT相关标志物及信号通路的变化。分别通过划痕、transwell和克隆形成实验检测肿瘤细胞的迁移、侵袭和克隆形成能力。采用MTS法检测细胞对紫杉醇的药物敏感性。结果与亲代PC3和DU145细胞相比,化疗耐药PC3-TxR和DU145-TxR细胞表现出EMT相关的标志物表达改变,包括E-cadherin表达下调和Vimentin、Snail与N-cadherin表达上调。当E-cadherin在PC3-TxR和DU-145-TxR细胞中过表达时,Vimentin和Caldun-1表达下调,肿瘤细胞的迁移和侵袭受到抑制。特别是E-cadherin过表达以后,PC3-TxR和DU145-TxR细胞对紫杉醇的敏感性被重新激活。并且,在亲代PC3和DU145细胞中沉默E-cadherin表达后,Vimentin和Snail表达上调,对紫杉醇的敏感性降低。有趣的是,与亲代PC3和DU145细胞相比,PC3-TxR和DU145-TxR细胞中Notch-1表达上调,而E-cadherin在这些细胞中的表达下调。我们的研究还显示,Notch信号通路抑制剂γ-分泌酶抑制剂可显著增加化疗耐药细胞对紫杉醇的敏感性。结论 E-cadherin下调可以激活Notch信号通路,从而增强PCa化疗耐药,抑制Notch信号通路可能逆转PCa化疗耐药。

An unusual mass arising from the vas deferens

An 18-year-old man presented with a history of fightsided abdominal pain and weight loss. Clinical examination revealed the presence of a right-sided abdominal mass arising from the pelvis. Baseline haematological and biochemical investigations were normal. A computerized tomography scan revealed a 78×56 mm cystic mass indenting the right posterolateral aspect of the bladder. The right kidney was absent with a congenital anomaly and duplication of the inferior vena cava below the left renal vein. A dimercaptosuccinic acid (DMSA) scan revealed