Role of Lamin A/C as Candidate Biomarker of Aggressiveness and Tumorigenicity in Glioblastoma Multiforme

Nuclear lamina components have long been regarded as scaffolding proteins, forming a dense fibrillar structure necessary for the maintenance of the nucleus shape in all the animal kingdom. More recently, mutations, aberrant localisation and deregulation of these proteins have been linked to several diseases, including cancer. Using publicly available data we found that the increased expression levels of the nuclear protein Lamin A/C correlate with a reduced overall survival in The Cancer Genome Atlas Research Network (TCGA) patients affected by glioblastoma multiforme (GBM). We show that the expression of the LMNA gene is linked to the enrichment of cancer-related pathways, particularly pathways related to cell adhesion and cell migration. Mimicking the modulation of LMNA in a GBM preclinical cancer model, we confirmed both in vitro and in vivo that the increased expression of LMNA is associated with an increased aggressiveness and tumorigenicity. In addition, delving into the possible mechanism behind LMNA-induced GBM aggressiveness and tumorigenicity, we found that the mTORC2 component, Rictor, plays a central role in mediating these effects.

Circulating miRNAs in Small Extracellular Vesicles Secreted by a Human Melanoma Xenograft in Mouse Brains

The identification of liquid biomarkers remains a major challenge to improve the diagnosis of melanoma patients with brain metastases. Circulating miRNAs packaged into tumor-secreted small extracellular vesicles (sEVs) contribute to tumor progression. To investigate the release of tumor-secreted miRNAs by brain metastasis, we developed a xenograft model where human metastatic melanoma cells were injected intracranially in nude mice. The comprehensive profiles of both free miRNAs and those packaged in sEVs secreted by the melanoma cells in the plasma demonstrated that most (80%) of the sEV-associated miRNAs were also present in serum EVs from a cohort of metastatic melanomas, included in a publicly available dataset. Remarkably, among them, we found three miRNAs (miR-224-5p, miR-130a-3p and miR-21-5p) in sEVs showing a trend of upregulation during melanoma progression. Our model is proven to be valuable for identifying miRNAs in EVs that are unequivocally secreted by melanoma cells in the brain and could be associated to disease progression.

Down-regulation of the Lamin A/C in neuroblastoma triggers the expansion of tumor initiating cells

Tumor-initiating cells constitute a population within a tumor mass that shares properties with normal stem cells and is considered responsible for therapy failure in many cancers. We have previously demonstrated that knockdown of the nuclear envelope component Lamin A/C in human neuroblastoma cells inhibits retinoic acid-mediated differentiation and results in a more aggressive phenotype. In addition, Lamin A/C is often lost in advanced tumors and changes in the nuclear envelope composition occur during tumor progression. Based on our previous data and considering that Lamin A/C is expressed in differentiated tissues, we hypothesize that the lack of Lamin A/C could predispose cells toward a stem-like phenotype, thus influencing the development of tumor-initiating cells in neuroblastoma. This paper demonstrates that knockdown of Lamin A/C triggers the development of a tumor-initiating cell population with self-renewing features in human neuroblastoma cells. We also demonstrates that the development of TICs is due to an increased expression of MYCN gene and that in neuroblastoma exists an inverse relationship between LMNA and MYCN expression.

Fabrication of Fully Dense UHTC by Combining SHS and SPS

<p>The combination of the Self-propagating High-temperature Synthesis (SHS) technique and the Spark Plasma Sintering (SPS) technology is adopted in this work for the fabrication of fully dense MB₂-SiC and MB₂-MC-SiC (M = Zr, Hf, Ta) Ultra High Temperature Ceramics (UHTCs). Specifically, Zr, Hf or Ta, B₄C,<br /> Si, and graphite reactants are first converted to the desired composites by SHS. For the case of the lowexothermic Ta-based compositions, a preliminary 20 min ball milling treatment of the starting reactants is required to activate the corresponding synthesis reactions. When the resulting powders are then subjected to consolidation by SPS, it is found that products with relative densities greater than 96% can be obtained for all systems investigated within 30 min of total processing time, when setting the dwell temperature to 1800 °C and the mechanical pressure to 20 MPa. Hardness, fracture toughness, and oxidation resistance characteristics of the resulting dense UHTCs are comparable to, or superior than, those relative to similar products synthesized by alternative, less rapid, processing routes. Moreover, it is found that the ternary composites display relatively low resistance to oxidation as a consequence of the lower SiC content in the composite, in comparison with the binary systems, as well as to the presence of transition metal carbides. Indeed, although the latter ones are potentially able to increase mechanical and resistance to ablation properties, they tend to oxidize rapidly to form MO₂ and CO_x, so that the resulting porosity make the material bulk more sensitive to oxidation.</p>

Clinical correlates of atypical depression and validation of the French version of the Scale for Atypical Symptoms (SAS)

BACKGROUND

The 8-item "Scale for Atypical Symptoms" (SAS) and its structured interview, the SIGH-SAD, have been developed to assess atypical symptoms of depression in winter depression. Although they are commonly used, no validation study has yet been conducted.

METHODS

270 consecutive depressed inpatients were assessed prospectively. Pearson's correlation coefficients between fulfilment of Liebowitz criteria for atypical depression and both the SAS score and the atypical balance [ratio of the AS score to the total score on the Hamilton Depression Rating Scale 29-item (HDRS-29)] were calculated. The SAS was evaluated against Liebowitz criteria using binary logistic regression. A ROC curve was performed with the atypical balance against the fulfilment of Liebowitz criteria.

RESULTS

18.5% of patients met the criteria for atypical depression. The presence of an atypical depression was significantly correlated with both the atypical score (r=0.42) and the atypical balance (r=0.51). The logistic regression showed that a higher score on the SAS, the absence of a somatic syndrome (ICD-10) and a lower HDRS-21 score were independent predictors of an atypical depression while age, gender and bipolarity were not. The ROC curve showed that an atypical balance of 29% was the optimal threshold for the diagnosis of atypical depression (sensitivity=0.86, specificity=0.79).

LIMITATION

Patients with bipolar I and II were not distinguished.

CONCLUSION

Atypical depression is relatively frequent in hospitalised patients. The concurrent validity of the French version of the SAS and its structured interview, the SIGH-SAD is satisfactory.

Échelle de peur de l’évaluation négative (FNE) : propriétés psychométriques de la traduction française

BACKGROUND

The Fear of Negative Evaluation scale (FNE: Watson and Friend, 1969) is the measure most commonly used to determine the degree to which people experience apprehension at the prospect of being negatively evaluated. Although the development of the FNE preceded the inclusion of social anxiety disorder (or social phobia) in the diagnostic classification system, it is widely used as a measure of cognitive symptoms because the feature tapped by this measure is at the core of recent cognitive models of social-anxiety. According to these models, socially anxious individuals divide their attention between the internal representations of their social self (negative images and "felt sense") and external cues that could be taken as a sign of negative evaluation by others. The FNE was validated in a student and patient population in English speaking countries. The English version demonstrates adequate empirical validity. It shows excellent internal consistency and one-factor structure. Test retest reliability is satisfying. It is proved to be sensible to change after treatment. It is well correlated with other measures of social anxiety demonstrating good convergent validity. However, divergent and discriminate validity have been a subject of controversy. The aim of the present study was to assess the psychometric properties of the French version of the FNE in order to obtain a valid instrument measuring the cognitive component of social anxiety.

METHOD

The social anxiety group consisted of 88 patients referred to our clinic for cognitive-behavioural group therapy. All met ICD-10 criteria for social phobia (generalized subtype) as determined by the Composite International Diagnostic Interview (social phobia section). Additional axis-I diagnostic information was obtained using the Mini International Neuropsychiatric Interview (MINI: Lecrubier et al., 1997) for ICD-10. The non-patient control group consisted of 80 participants who didn't respond to social anxiety CIDI criteria. All participants were rated by the assessor on the Liebowitz Social Anxiety Scale (LSAS) and completed the following self-report questionnaires: the Fear of Negative Evaluation questionnaire (FNE), the State-Trait-Anxiety Inventory (STAI A-B), and the Beck Depression Inventory (BDI 13).

RESULTS

The internal consistency is very good with Kuder-Richardson 20 coefficient of 0,94 corresponding to coefficients found in the validity studies of the original version of the FNE. One factor Anova tests showed that our two groups of subjects differed significantly on the FNE [F (1.166)=282.26, p<0.001]. Patients had a mean score of 25.6 with a standard deviation of 4.1 and the non patient control subjects had a mean score of 12.1 with a standard deviation of 6.1. This result confirms the empirical validity of the instrument. In the patient sample, the FNE was significantly correlated with the LSAS total score (r=0.55; p<0.001). This result indicates good convergent validity. However, the FNE was also significantly correlated with the BDI-13 (r=0.48; p<0.001) and the STAI B (r=0.47; p<0.001). However because high levels of general anxiety and depression are common among patients with social anxiety disorder, substantial correlations between measures of social anxiety and measures of general anxiety and depression should be probably expected. A multiple regression analysis shows a significant association of the FNE with the LSAS (Beta=0.39, p<0.001) and the STAIB (Beta=0.28, p<0.01) We explored the unidimensionality of the scale by using a principal component analysis of tetrachoric correlation suitable for dichotomic items. One sole factor with an eigenvalue superior to 1 emerged. We deduce therefore that our results are in favour of the unidimensionality of the French version of the FNE.

CONCLUSION

The present study shows that the French version of the FNE has good psychometric properties and differentiates social phobic patients from the non-clinical control subjects. Given the importance that models of social anxiety attribute to cognitive processes and the importance of cognitive techniques in its treatment, we consider that the French version of the FNE is an adequate and valid questionnaire to be used in research and therapy.

Selective attention in social phobia and the moderating effect of a concurrent depressive disorder

Studies using the modified Stroop colour naming task have provided results consistent with the hypothesis that social phobia is associated with an attentional bias towards negative social-evaluative words. However, these results could also have arisen as a consequence of non-attentional processes. For this reason, the present study uses a modified version of MacLeod et al.'s (J. Abnorm. Psychol. 95 (1986) 15) dot-probe task, which provides a more direct measure of attention. Patients with social phobia (n=28), patients with social phobia and a concurrent depressive disorder (n=33), and non-patients (n=40) were presented with word pairs each consisting of a neutral word and a threat word. The results indicated that patients with social phobia show an attentional bias towards social-threat words while non-patients tend to avoid social-threat words. Patients with social phobia and a concurrent depressive disorder behaved like non-patients, indicating that concurrent depression abolishes the attentional bias. Physical threat words were also included in the study. The main analysis indicated that social phobia is also associated with an attentional bias to physical threat. However, a post hoc analysis (which requires replication) suggested that the physical threat bias might have arisen because some social phobia patients also had another anxiety disorder in which physical concerns are likely to have been prominent. Overall, the results emphasise the importance of assessing comorbidity when investigating attentional biases.