The ABCC6 Transporter as a Paradigm for Networking from an Orphan Disease to Complex Disorders

The knowledge on the genetic etiology of complex disorders largely results from the study of rare monogenic disorders. Often these common and rare diseases show phenotypic overlap, though monogenic diseases generally have a more extreme symptomatology. ABCC6, the gene responsible for pseudoxanthoma elasticum, an autosomal recessive ectopic mineralization disorder, can be considered a paradigm gene with relevance that reaches far beyond this enigmatic orphan disease. Indeed, common traits such as chronic kidney disease or cardiovascular disorders have been linked to the ABCC6 gene. While during the last decade the awareness of the wide ramifications of ABCC6 has increased significantly, the gene itself and the transmembrane transporter it encodes have not unveiled all of the mysteries that surround them. To gain more insights, multiple approaches are being used including nextgeneration sequencing, computational methods, and various "omics" technologies. Much effort is made to place the vast amount of data that is gathered in an integrated system-biological network; the involvement of ABCC6 in common disorders provides a good view on the wide implications and potential of such a network. In this review, we summarize the network approaches used to study ABCC6 and the role of this gene in several complex diseases

Wt1 is required for cardiovascular progenitor cell formation through transcriptional control of Snail and E-cadherin

Epicardial epithelial-mesenchymal transition (EMT) is hypothesized to generate cardiovascular progenitor cells that differentiate into various cell types, including coronary smooth muscle and endothelial cells, perivascular and cardiac interstitial fibroblasts and cardiomyocytes. Here we show that an epicardial-specific knockout of Wt1 leads to a reduction of mesenchymal progenitor cells and their derivatives. We demonstrate that Wt1 is essential for repression of the epithelial phenotype in epicardial cells and during Embryonic Stem (ES) cell differentiation, through direct transcriptional regulation of Snail (Snai1) and E-cadherin (Cdh1), two of the major mediators of EMT. Some mesodermal lineages fail to form in Wt1 null embryoid bodies but this effect is rescued by the expression of Snai1, underlining the importance of EMT in generating these differentiated cells. These new insights into the molecular mechanisms regulating cardiovascular progenitor cells and EMT will shed light on the pathogenesis of heart diseases and may help the development of cell based therapies

Clinical Implication of Targeting of Cancer Stem Cells

The existence of cancer stem cells (CSCs) is receiving increasing interest particularly due to its potential ability to enter clinical routine. Rapid advances in the CSC field have provided evidence for the development of more reliable anticancer therapies in the future. CSCs typically only constitute a small fraction of the total tumor burden; however, they harbor self-renewal capacity and appear to be relatively resistant to conventional therapies. Recent therapeutic approaches aim to eliminate or differentiate CSCs or to disrupt the niches in which they reside. Better understanding of the biological characteristics of CSCs as well as improved preclinical and clinical trials targeting CSCs may revolutionize the treatment of many cancers. Copyright (c) 2012 S. Karger AG, Base

Metastatic phenotype and immunosuppressive tumour microenvironment in pancreatic ductal adenocarcinoma: Key role of the urokinase plasminogen activator (PLAU)

BackgroundPrevious studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition.MethodsThis study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis.ResultsOur analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis.ConclusionElevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU

A network analysis of the Internet Disorder Scale–Short Form (IDS9-SF): a large-scale cross-cultural study in Iran, Pakistan, and Bangladesh

The Internet Disorder Scale–Short Form (IDS9-SF) is a validated instrument assessing internet disorder which modified the internet gaming disorder criteria proposed in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). However, the relationships between the nine items in the IDS9-SF are rarely investigated. The present study used network analysis to investigate the features of the IDS9-SF among three populations in Bangladesh, Iran, and Pakistan. Data were collected (N = 1901; 957 [50.3%] females; 666 [35.0%] Pakistani, 533 [28.1%] Bangladesh, and 702 [36.9%] Iranians) using an online survey platform (e.g., Google Forms). All the participants completed the IDS9-SF. The central-stability-coefficients of the nine IDS9-SF items were 0.71, 0.89, 0.96, 0.98, 0.98, 1.00, 0.67, 0.79, and 0.91, respectively. The node centrality was stable and interpretable in the network. The Network Comparison Test (NCT) showed that the network structure had no significant differences among Pakistani, Bangladeshi, and Iranian participants (p-values = 0.172 to 0.371). Researchers may also use the IDS9-SF to estimate underlying internet addiction for their target participants and further explore and investigate the phenomenon related to internet addiction. Li Li, Mohammed A. Mamun, Firoj Al-Mamun, Irfan Ullah, Ismail Hosen, Syed Ahsan Zia, Ali Poorebrahim, Morteza Pourgholami, Chung-Ying Lin, Halley M. Pontes, Mark D. Griffiths & Amir H. Pakpou

Holoclone Forming Cells from Pancreatic Cancer Cells Enrich Tumor Initiating Cells and Represent a Novel Model for Study of Cancer Stem Cells

Pancreatic cancer is one of the direct causes of cancer-related death. High level of chemoresistance is one of the major obstacles of clinical treatment. In recent years, cancer stem cells have been widely identified and indicated as the origin of chemoresistance in multi-types of solid tumors. Increasing evidences suggest that cancer stem cells reside in the cells capable of forming holoclones continuously. However, in pancreatic cancer, holoclone-forming cells have not been characterized yet. Therefore, the goal of our present study was to indentify the holoclone-forming pancreatic cancer stem cells and develop an in vitro continuous colony formation system, which will greatly facilitate the study of pancreatic cancer stem cells.Pancreatic cancer cell line BxPC3 was submitted to monoclonal cultivation to generate colonies. Based on the morphologies, colonies were classified and analyzed for their capacities of secondary colony formation, long-term survival in vitro, tumor formation in vivo, and drug resistance. Flowcytometry and quantitative RT-PCR were performed to detect the expression level of cancer stem cells associated cell surface markers, regulatory genes and microRNAs in distinct types of colonies. Three types of colonies with distinct morphologies were identified and termed as holo-, mero-, and paraclones, in which only holoclones generated descendant colonies of all three types in further passages. Compared to mero- and paraclones, holoclones possessed higher capacities of long-term survival, tumor initiation, and chemoresistance. The preferential expression of cancer stem cells related marker (CXCR4), regulatory genes (BMI1, GLI1, and GLI2) and microRNAs (miR-214, miR-21, miR-221, miR-222 and miR-155) in holoclones were also highlighted.Our results indicate that the pancreatic tumor-initiating cells with high level of chemoresistance were enriched in holoclones derived from BxPC3 cell line. Generation of holoclones can serve as a novel model for studying cancer stem cells, and attribute to developing new anti-cancer drugs

Self-renewal and chemotherapy resistance of p75NTR positive cells in esophageal squamous cell carcinomas

<p>Abstract</p> <p>Background</p> <p>p75^NTRhas been used to isolate esophageal and corneal epithelial stem cells. In the present study, we investigated the expression of p75^NTRin esophageal squamous cell carcinoma (ESCC) and explored the biological properties of p75^NTR+cells.</p> <p>Methods</p> <p>p75^NTRexpression in ESCC was assessed by immunohistochemistry. p75^NTR+and p75^NTR-cells of 4 ESCC cell lines were separated by fluorescence-activated cell sorting. Differentially expressed genes between p75^NTR+and p75^NTR-cells were determined by real-time quantitative reverse transcription-PCR. Sphere formation assay, DDP sensitivity assay, ⁶⁴copper accumulation assay and tumorigenicity analysis were performed to determine the capacity of self-renewal, chemotherapy resistance and tumorigenicity of p75^NTR+cells.</p> <p>Results</p> <p>In ESCC specimens, p75^NTRwas found mainly confined to immature cells and absent in cells undergoing terminal differentiation. The percentage of p75^NTR+cells was 1.6%–3.7% in Eca109 and 3 newly established ESCC cell lines. The expression of Bmi-1, which is associated with self-renewal of stem cells, was significantly higher in p75^NTR+cells. p63, a marker identified in keratinocyte stem cells, was confined mainly to p75^NTR+cells. The expression of CTR1, which is associated with cisplatin (DDP)-resistance, was significantly decreased in p75^NTR+cells. Expression levels of differentiation markers, such as involucrin, cytokeratin 13, β1-integrin and β4-integrin, were lower in p75^NTR+cells. In addition, p75^NTR+cells generated both p75^NTR+and p75^NTR-cells, and formed nonadherent spherical clusters in serum-free medium supplemented with growth factors. Furthermore, p75^NTR+cells were found to be more resistant to DDP and exhibited lower ⁶⁴copper accumulation than p75^NTR-cells.</p> <p>Conclusion</p> <p>Our results demonstrated that p75^NTR+cells possess some characteristics of CSCs, namely, self-renewal and chemotherapy resistance. Chemotherapy resistance of p75^NTR+cells may probably be attributable to decreased expression of CTR1.</p

Switches, Excitable Responses and Oscillations in the Ring1B/Bmi1 Ubiquitination System

In an active, self-ubiquitinated state, the Ring1B ligase monoubiquitinates histone H2A playing a critical role in Polycomb-mediated gene silencing. Following ubiquitination by external ligases, Ring1B is targeted for proteosomal degradation. Using biochemical data and computational modeling, we show that the Ring1B ligase can exhibit abrupt switches, overshoot transitions and self-perpetuating oscillations between its distinct ubiquitination and activity states. These different Ring1B states display canonical or multiply branched, atypical polyubiquitin chains and involve association with the Polycomb-group protein Bmi1. Bistable switches and oscillations may lead to all-or-none histone H2A monoubiquitination rates and result in discrete periods of gene (in)activity. Switches, overshoots and oscillations in Ring1B catalytic activity and proteosomal degradation are controlled by the abundances of Bmi1 and Ring1B, and the activities and abundances of external ligases and deubiquitinases, such as E6-AP and USP7