Alterations of miRNA Expression in Diffuse Hyperplastic Perilobar Nephroblastomatosis: Mapping the Way to Understanding Wilms' Tumor Development and Differential Diagnosis.

Wilms' tumor (WT) is the most common renal malignancy in children. In diffuse hyperplastic perilobar nephroblastomatosis (DHPLN), nephrogenic rests result in a bulky enlargement of the kidney, a condition considered as a premalignant state before WT. Despite relevant clinical differences between WT and DHPLN, they are often challenging to distinguish based on histology. Molecular markers would improve differential diagnosis, but none are available at present. In our study, we investigated the potential of microRNAs (miRNAs) as such biomarkers, also aiming to shed light on the chronological order of expression changes. Formalin-fixed, paraffin-embedded (FFPE) samples from four DHPLN cases and adjacent healthy tissues were tested using a PCR array containing primers for 84 miRNAs implicated in genitourinary cancer. Expression in DHPLN was compared to WT data available in dbDEMC. Let-7, miR-135, miR-146a-5p, miR-182-5p, miR-183-5p, miR-20b-3p, miR-29b-3p, miR-195-5p and miR-17-5p showed potential to be used as biomarkers to distinguish WT and DHPLN in cases when traditional differential diagnosis is inconclusive. Our study also revealed miRNAs which may play a role in the initial steps of the pathogenesis (at a precancerous stage) and ones which become deregulated later in WT. More experiments are needed to confirm our observations and find new candidate markers.

Analysis and identification of ADP-ribosylated proteins of Streptomyces coelicolor M145.

Mono-ADP-ribosylation is the enzymatic transfer of ADP-ribose from NAD(+) to acceptor proteins catalyzed by ADP-ribosyltransferases. Using m-aminophenylboronate affinity chromatography, 2D-gel electrophoresis, in-gel digestion and MALDI-TOF analysis we have identified eight in vitro ADP-ribosylated proteins in Streptomyces coelicolor, which can be classified into three categories: (i) secreted proteins; (ii) metabolic enzymes using NAD(+)/NADH or NADP(+)/NADPH as coenzymes; and (iii) other proteins. The secreted proteins could be classified into two functional categories: SCO2008 and SC05477 encode members of the family of periplasmic extracellular solute-binding proteins, and SCO6108 and SC01968 are secreted hydrolases. Dehydrogenases are encoded by SC04824 and SC04771. The other targets are GlnA (glutamine synthetase I., SC02198) and SpaA (starvation-sensing protein encoded by SC07629). SCO2008 protein and GlnA had been identified as ADP-ribosylated proteins in previous studies. With these results we provided experimental support for a previous suggestion that ADP-ribosylation may regulate membrane transport and localization of periplasmic proteins. Since ADP-ribosylation results in inactivation of the target protein, ADP-ribosylation of dehydrogenases might modulate crucial primary metabolic pathways in Streptomyces. Several of the proteins identified here could provide a strong connection between protein ADP-ribosylation and the regulation of morphological differentiation in S. coelicolor.

Epstein-Barr virus-encoded EBNA-5 binds to Epstein-Barr virus-induced Fte1/S3a protein.

Epstein-Barr virus (EBV) transforms resting human B cells into immortalized immunoblasts. EBV-encoded nuclear antigens EBNA-5 (also called EBNA-LP) is one of the earliest viral proteins expressed in freshly infected B cells. We have recently shown that EBNA-5 binds p14ARF, a nucleolar protein that regulates the p53 pathway. Here, we report the identification of another protein with partially nucleolar localization, the v-fos transformation effector Fte-1 (Fte-1/S3a), as an EBNA-5 binding partner. In transfected cells, Fte-1/S3a and EBNA-5 proteins showed high levels of colocalization in extranucleolar inclusions. Fte-1/S3a has multiple biological functions. It enhances v-fos-mediated cellular transformation and is part of the small ribosomal subunit. It also interacts with the transcriptional factor CHOP and apoptosis regulator poly(ADP-ribose) polymerase (PARP). Fte-1/S3a is regularly expressed at high levels in both tumors and cancer cell lines. Its high expression favors the maintenance of malignant phenotype and undifferentiated state, whereas its down-regulation is associated with cellular differentiation and growth arrest. Here, we show that EBV-induced B cell transformation leads to the up-regulation of Fte-1/S3a. We suggest that EBNA-5 through binding may influence the growth promoting, differentiation inhibiting, or apoptosis regulating functions of Fte-1/S3a.