ABI3 ectopic expression reduces in vitro and in vivo cell growth properties while inducing senescence

<p>Abstract</p> <p>Background</p> <p>Mounting evidence has indicated that <it>ABI3 </it>(ABI family member 3) function as a tumor suppressor gene, although the molecular mechanism by which ABI3 acts remains largely unknown.</p> <p>Methods</p> <p>The present study investigated <it>ABI3 </it>expression in a large panel of benign and malignant thyroid tumors and explored a correlation between the expression of ABI3 and its potential partner ABI3-binding protein (ABI3BP). We next explored the biological effects of <it>ABI3 </it>ectopic expression in thyroid and colon carcinoma cell lines, in which its expression was reduced or absent.</p> <p>Results</p> <p>We not only observed that <it>ABI3 </it>expression is reduced or lost in most carcinomas but also that there is a positive correlation between <it>ABI3 </it>and <it>ABI3BP </it>expression. Ectopic expression of <it>ABI3 </it>was sufficient to lead to a lower transforming activity, reduced tumor <it>in vitro </it>growth properties, suppressed <it>in vitro </it>anchorage-independent growth and <it>in vivo </it>tumor formation while, cellular senescence increased. These responses were accompanied by the up-regulation of the cell cycle inhibitor <it>p21 </it>^WAF1and reduced ERK phosphorylation and <it>E2F1 </it>expression.</p> <p>Conclusions</p> <p>Our result links <it>ABI3 </it>to the pathogenesis and progression of some cancers and suggests that ABI3 or its pathway might have interest as therapeutic target. These results also suggest that the pathways through which <it>ABI3 </it>works should be further characterized.</p

Lung fibroblasts from patients with emphysema show markers of senescence in vitro

BACKGROUND: The loss of alveolar walls is a hallmark of emphysema. As fibroblasts play an important role in the maintenance of alveolar structure, a change in fibroblast phenotype could be involved in the pathogenesis of this disease. In a previous study we found a reduced in vitro proliferation rate and number of population doublings of parenchymal lung fibroblasts from patients with emphysema and we hypothesized that these findings could be related to a premature cellular aging of these cells. In this study, we therefore compared cellular senescence markers and expression of respective genes between lung fibroblasts from patients with emphysema and control patients without COPD. METHODS: Primary lung fibroblasts were obtained from 13 patients with moderate to severe lung emphysema (E) and 15 controls (C) undergoing surgery for lung tumor resection or volume reduction (n = 2). Fibroblasts (8E/9C) were stained for senescence-associated β-galactosidase (SA-β-Gal). In independent cultures, DNA from lung fibroblasts (7E/8C) was assessed for mean telomere length. Two exploratory 12 k cDNA microarrays were used to assess gene expression in pooled fibroblasts (3E/3C). Subsequently, expression of selected genes was evaluated by quantitative PCR (qPCR) in fibroblasts of individual patients (10E/9C) and protein concentration was analyzed in the cell culture supernatant. RESULTS: The median (quartiles) percentage of fibroblasts positive for SA-β-Gal was 4.4 (3.2;4.7) % in controls and 16.0 (10.0;24.8) % in emphysema (p = 0.001), while telomere length was not different. Among the candidates for differentially expressed genes in the array (factor ≥ 3), 15 were upregulated and 121 downregulated in emphysema. qPCR confirmed the upregulation of insulin-like growth factor-binding protein (IGFBP)-3 and IGFBP-rP1 (p = 0.029, p = 0.0002), while expression of IGFBP-5, -rP2 (CTGF), -rP4 (Cyr61), FOSL1, LOXL2, OAZ1 and CDK4 was not different between groups. In line with the gene expression we found increased cell culture supernatant concentrations of IGFBP-3 (p = 0.006) in emphysema. CONCLUSION: These data support the hypothesis that premature aging of lung fibroblasts occurs in emphysema, via a telomere-independent mechanism. The upregulation of the senescence-associated IGFBP-3 and -rP1 in emphysema suggests that inhibition of the action of insulin and insulin-like growth factors could be involved in the reduced in vitro-proliferation rate

Global gene expression profiling of oral cavity cancers suggests molecular heterogeneity within anatomic subsites

<p>Abstract</p> <p>Background</p> <p>Oral squamous cell carcinoma (OSCC) is a frequent neoplasm, which is usually aggressive and has unpredictable biological behavior and unfavorable prognosis. The comprehension of the molecular basis of this variability should lead to the development of targeted therapies as well as to improvements in specificity and sensitivity of diagnosis.</p> <p>Results</p> <p>Samples of primary OSCCs and their corresponding surgical margins were obtained from male patients during surgery and their gene expression profiles were screened using whole-genome microarray technology. Hierarchical clustering and Principal Components Analysis were used for data visualization and One-way Analysis of Variance was used to identify differentially expressed genes. Samples clustered mostly according to disease subsite, suggesting molecular heterogeneity within tumor stages. In order to corroborate our results, two publicly available datasets of microarray experiments were assessed. We found significant molecular differences between OSCC anatomic subsites concerning groups of genes presently or potentially important for drug development, including mRNA processing, cytoskeleton organization and biogenesis, metabolic process, cell cycle and apoptosis.</p> <p>Conclusion</p> <p>Our results corroborate literature data on molecular heterogeneity of OSCCs. Differences between disease subsites and among samples belonging to the same TNM class highlight the importance of gene expression-based classification and challenge the development of targeted therapies.</p

Environmental enrichment has no effect on the development of dopaminergic and GABAergic fibers during methylphenidate treatment of early traumatized gerbils

It is widely believed, that environmental factors play a crucial role in the etiology and outcome of psychiatric diseases such as Attention-Deficit/Hyperactivity Disorder (ADHD). A former study from our laboratory has shown that both methylphenidate (MP) and handling have a positive effect on the dopaminergic fiber density in the prefrontal cortex (PFC) of early traumatized gerbils (Meriones unguiculatus). The current study was performed to investigate if enriched environment during MP application has an additional influence on the dopaminergic and GABAergic fiber densities in the PFC and amygdala in this animal model

The MDM2-p53 pathway is involved in preconditioning-induced neuronal tolerance to ischemia.

Brain preconditioning (PC) refers to a state of transient tolerance against a lethal insult that can be evoked by a prior mild event. It is thought that PC may induce different pathways responsible for neuroprotection, which may involve the attenuation of cell damage pathways, including the apoptotic cell death. In this context, p53 is a stress sensor that accumulates during brain ischemia leading to neuronal death. The murine double minute 2 gene (MDM2), a p53-specific E3 ubiquitin ligase, is the main cellular antagonist of p53, mediating its degradation by the proteasome. Here, we study the role of MDM2-p53 pathway on PC-induced neuroprotection both in cultured neurons (in vitro) and rat brain (in vivo). Our results show that PC increased neuronal MDM2 protein levels, which prevented ischemiainduced p53 stabilization and neuronal death. Indeed, PC attenuated ischemia-induced activation of the p53/PUMA/caspase-3 signaling pathway. Pharmacological inhibition of MDM2-p53 interaction in neurons abrogated PC-induced neuroprotection against ischemia. Finally, the relevance of the MDM2-p53 pathway was confirmed in rat brain using a PC model in vivo. These findings demonstrate the key role of the MDM2-p53 pathway in PC-induced neuroprotection against a subsequent ischemic insult and poses MDM2 as an essential target in ischemic tolerance

Possible Associations of NTRK2 Polymorphisms with Antidepressant Treatment Outcome: Findings from an Extended Tag SNP Approach

Background: Data from clinical studies and results from animal models suggest an involvement of the neurotrophin system in the pathology of depression and antidepressant treatment response. Genetic variations within the genes coding for the brain-derived neurotrophic factor (BDNF) and its key receptor Trkb (NTRK2) may therefore influence the response to antidepressant treatment. Methods: We performed a single and multi-marker association study with antidepressant treatment outcome in 398 depressed Caucasian inpatients participating in the Munich Antidepressant Response Signature (MARS) project. Two Caucasian replication samples (N = 249 and N = 247) were investigated, resulting in a total number of 894 patients. 18 tagging SNPs in the BDNF gene region and 64 tagging SNPs in the NTRK2 gene region were genotyped in the discovery sample; 16 nominally associated SNPs were tested in two replication samples. Results: In the discovery analysis, 7 BDNF SNPs and 9 NTRK2 SNPs were nominally associated with treatment response. Three NTRK2 SNPs (rs10868223, rs1659412 and rs11140778) also showed associations in at least one replication sample and in the combined sample with the same direction of effects ($P_{corr}$ = .018, $P_{corr}$ = .015 and $P_{corr}$ = .004, respectively). We observed an across-gene BDNF-NTRK2 SNP interaction for rs4923468 and rs1387926. No robust interaction of associated SNPs was found in an analysis of BDNF serum protein levels as a predictor for treatment outcome in a subset of 93 patients. Conclusions/Limitations: Although not all associations in the discovery analysis could be unambiguously replicated, the findings of the present study identified single nucleotide variations in the BDNF and NTRK2 genes that might be involved in antidepressant treatment outcome and that have not been previously reported in this context. These new variants need further validation in future association studies