LEADeR role of miR-205 host gene as long noncoding RNA in prostate basal cell differentiation

Though miR-205 function has been largely characterized, the nature of its host gene, MIR205HG, is still completely unknown. Here, we show that only lowly expressed alternatively spliced MIR205HG transcripts act as de facto pri-miRNAs, through a process that involves Drosha to prevent unfavorable splicing and directly mediate miR-205 excision. Notably, MIR205HG-specific processed transcripts revealed to be functional per se as nuclear long noncoding RNA capable of regulating differentiation of human prostate basal cells through control of the interferon pathway. At molecular level, MIR205HG directly binds the promoters of its target genes, which have an Alu element in proximity of the Interferon-Regulatory Factor (IRF) binding site, and represses their transcription likely buffering IRF1 activity, with the ultimate effect of preventing luminal differentiation. As MIR205HG functions autonomously from (albeit complementing) miR-205 in preserving the basal identity of prostate epithelial cells, it warrants reannotation as LEADeR (Long Epithelial Alu-interacting Differentiation-related RNA)

MicroRNA-Mediated Control of Prostate Cancer Metastasis: Implications for the Identification of Novel Biomarkers and Therapeutic Targets

Prostate cancer is the most prevalent tumor in the male population and the second leading cause of cancer-related death in men in Western countries. Besides genetic and epigenetic aberrations in protein coding genes, alterations in microRNAs equally contribute to prostate cancer initiation and progression. In this context, a plethora of overwhelming evidence establishes the involvement of microRNAs as essential actors in the multi-step cascade fostering a prostate cancer cell to leave the primary tumor and form secondary tumors at distant sites. Herein, we describe how specific microRNAs may impinge on the different stages of prostate cancer metastasis and review published profiling studies in which microRNA expression data have been analyzed in relation to clinical parameters of progression for the identification of novel biomarkers. We also provide evidence concerning the possibility to manipulate metastasis-related microRNA functions, either by mimicking or inhibiting them, as a highly promising strategy for the development of innovative therapeutic approaches for the advanced disease

Proprietà barriera e meccaniche di film edibili a base di "whey protein isolate" e pectine preparati in presenza di trensglutaminasi

I film edibili rappresentano una valida alternativa ai film plastici derivati dal petrolio. I film edibili possono essere costituiti da proteine, polisaccaridi e lipidi. La reticolazione di tali film può essere migliorata ricorrendo ad agenti chimici, come la glutaraldeide, o ad agenti enzimatici, quali la transglutaminasi (Tgasi) (Di Pierro et al., 2005; Mariniello, Porta 2005). E’ noto che i componenti dei film e il loro grado di reticolazione hanno un effetto sulle proprietà meccaniche e di permeabilità. Recentemente nei nostri laboratori è stato dimostrato che film idrocolloidali a base mista composti da proteine e polisaccaridi possiedono migliorate proprietà barriera e meccaniche quando la componente proteica è modificata con l’enzima Tgasi (Di Pierro et al., 2010; Mariniello et al., 2010). Nel presente lavoro sono stati effettuati studi per preparare film composti da “whey protein isolate” (WPI) e pectine di limone. Una parte dello studio è stata indirizzata ad indagare il pH nel quale si ha il numero massimo di cariche dei componenti e quindi il maggior numero di interazioni (pH di complessazione, pHc). A tal scopo sono state fatte titolazioni potenziometriche di soluzioni di WPI e pectine miscelate a rapporti diversi. Il pHc è stato determinato a 5.1 mentre il miglior rapporto per la formazione dei complessi è stato trovato a 4:1 WPI-pectine. I film ottenuti in presenza di enzima possiedono diminuite proprietà barriera (H20, CO2, O2). Successivamente sono state misurate le proprietà meccaniche dei film: carico massimo a rottura (TS), percentuale di deformazione (E%) ed modulo di Young (Young´s modulus). I risultati hanno mostrato un aumento della TS e E% all´aumentare del pH, quando quest’ultimo si avvicina al valore di 5.6 (pI medio delle sieroproteine del WPI). In generale è possibile apprezzare che la presenza dell´enzima favorisce una maggiore reticolazione del film migliorandone le proprietà meccaniche

miR-875-5p counteracts epithelial-to-mesenchymal transition and enhances radiation response in prostate cancer through repression of the EGFR-ZEB1 axis

Radiotherapy is one of the main treatment choices for non-metastatic prostate cancer (PCa), although development of radioresistance limits its effectiveness. Mounting evidence supports the ability of microRNAs to interfere with different radioresistance-associated pathways, suggesting their potential as radiosensitizers. Here, we demonstrate that reconstitution of miR-875-5p, whose expression is down-regulated in PCa clinical samples and directly correlates with that of E-cadherin, was able to enhance radiation response in PCa cell lines and xenografts through EGFR direct targeting. Consistent with the established role of EGFR in sustaining epithelial-to-mesenchymal transition (EMT) and promoting DNA repair following radiation-induced nuclear translocation, we found that miR-875-5p reconstitution in PCa cells counteracted EMT and impaired DNA lesion clearance. Down-regulation of the EMT-inducing transcription factor ZEB1, which also plays a role in homologous recombination-mediated repair of DNA lesions by regulating CHK1 expression, was found to be a major determinant of miR-875-5p-induced radiosensitization, as confirmed by phenocopy experiments showing that siRNA-mediated ZEB1 knock-down was able to reproduce the microRNA radiosensitizing effect. Overall, our data support the clinical interest in developing a novel therapeutic approach based on miR-875-5p reconstitution to increase PCa response to radiotherapy

miR-205 regulates basement membrane deposition in human prostate: implications for cancer development

The basement membrane (BM) is a layer of specialized extracellular matrix that surrounds normal prostate glands and preserves tissue integrity. Lack or discontinuity of the BM is a prerequisite for tumor cell invasion into interstitial spaces, thus favoring metastasis. Therefore, BM maintenance represents a barrier against cancer development and progression. In the study, we show that miR-205 participates in a network involving \u394Np63\u3b1, which is essential for maintenance of the BM in prostate epithelium. At the molecular level, \u394Np63\u3b1 is able to enhance miR-205 transcription by binding to its promoter, whereas the microRNA can post-transcriptionally limit the amount of \u394Np63\u3b1 protein, mostly by affecting \u394Np63\u3b1 proteasomal degradation rather than through a canonical miRNA/target interaction. Functionally, miR-205 is able to control the deposition of laminin-332 and its receptor integrin-\u3b24. Hence, pathological loss of miR-205, as widely observed in prostate cancer, may favor tumorigenesis by creating discontinuities in the BM. Here we demonstrate that therapeutic replacement of miR-205 in prostate cancer (PCa) cells can restore BM deposition and 3D organization into normal-like acinar structures, thus hampering cancer progression

TMEM59 potentiates Wnt signaling by promoting signalosome formation

Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multi-meric Wnt–FZD assemblies via intramembrane interactions. Subsequently, these Wnt–FZD–TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions

TMEM59 potentiates Wnt signaling by promoting signalosome formation

Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt-FZD assemblies via intramembrane interactions. Subsequently, these Wnt-FZD-TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions