Electronic phase separation near the superconductor-insulator transition of Nd1+xBa2−xCu3O7−δ thin films studied by an electric-field-induced doping effect

We report a detailed study of the transport properties of Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films with doping changed by field effect. The data cover the whole superconducting to insulating transition and show remarkable Similarities with the effect of chemical doping in high critical temperature superconductors. The results suggest that the add-on of carriers is accompanied by an electronic phase separation, independent on the details of the doping mechanism

Mathematics anxiety, working memory, and mathematics performance in secondary-school children

Mathematics anxiety (MA) has been defined as \u201ca feeling of tension and anxiety that interferes with the manipulation of numbers and the solving of math problems in a wide variety of ordinary life and academic situations\u201d. Previous studies have suggested that a notable proportion of children in primary and secondary school suffer from MA, which is negatively correlated with calculation skills. The processing efficiency and attentional control theories suggest that working memory (WM) also plays an important part in such anxious feelings. The present study aimed to analyze the academic achievement and cognitive profiles of students with high math anxiety (HMA) and low math anxiety (LMA). Specifically, 32 students with HMA and 34 with LMA matched for age, gender, generalized anxiety, and vocabulary attending sixth to eighth grades were selected from a larger sample. The two groups were tested on reading decoding, reading comprehension, mathematics achievement, and on verbal short-term memory and WM. Our findings showed that HMA students were weak in several measures of mathematics achievement, but not in reading and writing skills, and that students with HMA reported lower scores on short-term memory and WM performances (with associated difficulties in inhibiting irrelevant information) than children with LMA. In addition, a logistic regression showed that weaknesses in inhibitory control and fact retrieval were the strongest variables for classifying children as having HMA or LMA

Numb Expression Contributes to the Maintenance of an Undifferentiated State in Human Epidermis.

The epidermis is a stratified epithelium with a stem cell subpopulation in the basal layer that constantly replicates and periodically detaches from the base, undergoing a differentiation process that involves various developmental signals and regulatory pathways. During the last 10 years, a number of studies tried to elucidate the intricate scenario that maintains the epithelial shield during the entire life span. In our study, we investigated the role of Numb in the skin compartment and, in particular, its involvement in stem cell maintenance. Numb expression in the skin compartment was assessed by immunofluorescence and immunohistochemistry analysis. We evaluated Numb expression in primary epithelial cells at various differentiative stages. Moreover, we overexpressed Numb in the isolated population enriched for undifferentiated progenitors to establish its involvement in in vitro differentiation. We demonstrated that Numb in high-proliferating epithelial undifferentiated progenitors contributes to the maintenance of an undifferentiated state. This regulation involves the E3 ligases Itch binding. Moreover, the analysis of a cohort of cutaneous carcinomas showed that Numb is highly expressed in squamous cell carcinoma (SCC), where we observed a direct correlation between the expression of Numb and Ki-67. Our data indicate for the first time that Numb is involved in the maintenance of the undifferentiated proliferating stem cell pool in the epithelial basal layer and its expression could become a new marker in skin cancer

Lung Cancer Organoids. The Rough Path to Personalized Medicine

Lung cancer is the leading cause of cancer death worldwide. Despite significant advances in research and therapy, a dismal 5-year survival rate of only 10–20% urges the development of reliable preclinical models and effective therapeutic tools. Lung cancer is characterized by a high degree of heterogeneity in its histology, a genomic landscape, and response to therapies that has been traditionally difficult to reproduce in preclinical models. However, the advent of three-dimensional culture technologies has opened new perspectives to recapitulate in vitro individualized tumor features and to anticipate treatment efficacy. The generation of lung cancer organoids (LCOs) has encountered greater challenges as compared to organoids derived from other tumors. In the last two years, many efforts have been dedicated to optimizing LCO-based platforms, resulting in improved rates of LCO production, purity, culture timing, and long-term expansion. However, due to the complexity of lung cancer, further advances are required in order to meet clinical needs. Here, we discuss the evolution of LCO technology and the use of LCOs in basic and translational lung cancer research. Although the field of LCOs is still in its infancy, its prospective development will likely lead to new strategies for drug testing and biomarker identification, thus allowing a more personalised therapeutic approach for lung cancer patients

Blocking the APRIL circuit enhances acute myeloid leukemia cell chemosensitivity.

Resistance to chemotherapy-induced cell death represents a major obstacle in the treatment of acute myeloid leukemia. APRIL (A Proliferation Inducing Ligand) is a member of the tumor necrosis factor superfamily that plays a key role in normal B-cell development, while promoting survival and proliferation of malignant B cells. We investigated APRIL expression and activity in acute myeloid leukemia. We found that APRIL mRNA and protein, including the secreted form, are expressed in leukemic cells of patients with M0, M2 and M4 acute myeloid leukemia subtypes but not in normal hematopoietic progenitors. Retrovirus-mediated APRIL expression in normal hematopoietic progenitors confers resistance to chemotherapeutic drugs-induced apoptosis. Conversely, blocking APRIL function by recombinant soluble APRIL receptors increased chemotherapeutic drugs-induced cell adeath in acute myeloid leukemia cells. These results indicate that APRIL acts in an autocrine fashion to protect acute myeloid leukemia cells from drug-induced death and foresee a therapeutic potential of APRIL antagonists in the treatment of acute myeloid leukemia

Histone acetyltransferase inhibitor CPTH6 preferentially targets lung cancer stem-like cells

Cancer stem cells (CSCs) play an important role in tumor initiation, progression, therapeutic failure and tumor relapse. In this study, we evaluated the efficacy of the thiazole derivative 3-methylcyclopentylidene-[4-(4’-chlorophenyl)thiazol-2-yl] hydrazone (CPTH6), a novel pCAF and Gcn5 histone acetyltransferase inhibitor, as a small molecule that preferentially targets lung cancer stem-like cells (LCSCs) derived from non-small cell lung cancer (NSCLC) patients. Notably, although CPTH6 inhibits the growth of both LCSC and NSCLC cell lines, LCSCs exhibit greater growth inhibition than established NSCLC cells. Growth inhibitory effect of CPTH6 in LCSC lines is primarily due to apoptosis induction. Of note, differentiated progeny of LCSC lines is more resistant to CPTH6 in terms of loss of cell viability and reduction of protein acetylation, when compared to their undifferentiated counterparts. Interestingly, in LCSC lines CPTH6 treatment is also associated with a reduction of stemness markers. By using different HAT inhibitors we provide clear evidence that inhibition of HAT confers a strong preferential inhibitory effect on cell viability of undifferentiated LCSC lines when compared to their differentiated progeny. In vivo, CPTH6 is able to inhibit the growth of LCSC-derived xenografts and to reduce cancer stem cell content in treated tumors, as evidenced by marked reduction of tumor-initiating capacity in limiting dilution assays. Strikingly, the ability of CPTH6 to inhibit tubulin acetylation is also confirmed in vivo. Overall, our studies propose histone acetyltransferase inhibition as an attractive target for cancer therapy of NSCLC

The secretion and maturation of prosaposin and procathepsin D are blocked in embryonic neural progenitor cells

The notion that prosaposin (Prosap) is likely involved in brain development and regeneration led us to explore its expression in stem/progenitor neural cells and its fate after cell differentiation. The expression of procathepsin-cathepsin D (proCath-Cath D), an endoprotease that plays an important role in the processing and sorting of Prosap, has been concomitantly examined. Our data evidenced that in embryonic human neural progenitor cells (eHNPCs) intact and high molecular weight intermediate forms of Prosap and intermediate forms of Cath D accumulated inside the cells, while the formation of saposins and mature Cath D was impaired. Furthermore, neither Prosap nor proCath D were secreted from eHNPCs. The block of the processing and secretion shared by Prosap and proCath D was overcome during the course of differentiation of eHNPCs into a mixed population of astrocytes and neuronal cells. Upon differentiation, large amounts of Prosap and proCath D were secreted from the cells, while saposins and mature Cath D were produced inside the cells. The dramatic accumulation of Prosap (an antiapoptotic factor) and reduction of mature Cath D (a proapoptotic factor) in the undifferentiated eHNPCs most likely play a role in the molecular mechanisms regulating the resistance to apoptotic signals of these cells and might represent a critically important issue in HNPCs biology. © 2008 Elsevier B.V. All rights reserved

Role of autophagy in the maintenance and function of cancer stem cells

Recent advances in experimental technologies and cancer models have made possible to demonstrate that the tumor is a dynamic system comprising heterogeneous populations of cancer cells organized in a hierarchical fashion with cancer stem cells (CSCs) at the apex. CSCs are immature cells characterized by self-renewal property and long-term repopulation potential. CSCs have been causally linked to cancer initiation, propagation, spreading, recurrence and relapse as well as to resistance to anticancer therapy. A growing body of evidence suggests that the function and physiology of CSCs may be influenced by genetic/epigenetic factors and tumor environment. In this context, macroautophagy is a lysosomal degradative process (herein referred to as autophagy) critical for the adaptive response to stress and the preservation of cellular and tissue homeostasis in all eukaryotes that may have a crucial role of in the origin, maintenance and invasiveness of CSCs. The activation of the autophagic machinery is also considered as an adaptive response of CSCs to perturbation of tumor microenvironment, caused for instance by anticancer therapy. Nevertheless, compelling preclinical and clinical evidence on the cytoprotective role of autophagy for CSCs is still missing. Here, we summarize the results on the contribution of autophagy in CSCs and how it impacts tumorigenesis and tumor progression. We also discuss the therapeutical potential of the modulation of autophagy as a means to eradicate CSCs

DNA Damage in Stem Cells

Both embryonic and adult stem cells are endowed with a superior capacity to prevent the accumulation of genetic lesions, repair them, or avoid their propagation to daughter cells, which would be particularly detri- mental to the whole organism. Inducible pluripotent stem cells also display a robust DNA damage response, but the stability of their genome is often conditioned by the mutational history of the cell population of origin, which constitutes an obstacle to clinical applications. Cancer stem cells are particularly tolerant to DNA dam- age and fail to undergo senescence or regulated cell death upon accumulation of genetic lesions. Such a resistance contributes to the genetic drift of evolving tumors as well as to their limited sensitivity to chemo- and radiotherapy. Here, we discuss the pathophysiological and therapeutic implications of the molecular pathways through which stem cells cope with DNA damage