Expression of microRNAs-106b in nonsmall cell lung cancer.

AIM: To explore the expression of microRNA-106b (miRNA-106b) in nonsmall cell lung cancer (NSCLC). SETTINGS AND DESIGN: miRNAs are short regulatory RNAs that negatively modulate gene expression at the posttranscriptional level, and are deeply involved in the pathogenesis of several types of cancer. miRNA-106b has been shown to play an oncogenic role in tumor progression. The expression of miRNA-106b is detected in this study. SUBJECTS AND METHODS: Quantitative reverse transcription polymerase chain reaction and Northern blotting were used to detect the expression level of miRNA-106b in 200 NSCLC samples. STATISTICAL ANALYSIS USED: All statistical analyses were performed using SPSS 16.0 software. Results were statistically evaluated using the Kruskal-Wallis test and Mann-Whitney U-test. Survival curves were estimated by the Kaplan-Meier method and P < 0.05 was considered to be statistically significant. RESULTS: miRNA-106b expression is increased in NSCLC tissues. Statistical analysis showed that overexpression of miRNA-106b was strongly associated with lymph node metastasis, stage of tumor node metastasis classification, and poor prognosis. Moreover, there was a significant difference in the miRNA-106b expression levels between smoking and nonsmoking patients. Multivariate Cox regression analysis showed that miRNA-106b was an independent prognostic factor for NSCLC patients. CONCLUSIONS: These data suggest that aberrantly expressed miRNA-106b may contribute to the development of NSCLC.

Defining the pattern of initiation of monomorphic ventricular tachycardia using the beat-to-beat intervals recorded on implantable cardioverter defibrillators from the RAFT study: A computer-based algorithm.

Arrhythmia onset pattern may have important implications on morbidity, recurrent implantable cardioverter defibrillator (ICD) shocks, and mortality, given the proposed correlation between initiation pattern and arrhythmia mechanism. Therefore, we developed and tested a computer-based algorithm to differentiate the pattern of initiation based on the beat-to-beat intervals of the ventricular tachycardia (VT) episodes in ICD recordings from the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT). Intervals on intracardiac electrograms from ICDs were analyzed backwards starting from the marker of VT detection, comparing each interval with the average tachycardia cycle length. If the morphology of the beat initiating the VT was similar to the morphology of the VT itself, the episode was considered sudden. If the morphology of the beat initiating the VT was not similar to the morphology of the VT itself, the episode was considered non-sudden. The capability of the algorithm to classify the pattern of initiation based only on the beat-to-beat intervals allows for the classification and analysis of large datasets to further investigate the clinical importance of classifying VT initiation. If analysis of the VT initiation proves to be of clinical value, this algorithm could potentially be integrated into ICD software, which would make it easily accessible and potentially helpful in clinical decision-making.

Effects of microRNA-330 on vulnerable atherosclerotic plaques formation and vascular endothelial cell proliferation through the WNT signaling pathway in acute coronary syndrome.

This study is designed to investigate the effects of microRNA (miR)-330 on atherosclerotic plaques formation and vascular endothelial (VE) cell proliferation by targeting MAPK8 through the WNT signaling pathway in rats with acute coronary syndrome (ACS). Expression of hemodynamic variables were tested. Rats were allocated into control, blank, negative control (NC), miR-330 mimic, miR-330 inhibitor, DDK-1, miR-330 inhibitor + DDK-1 groups. ELISA was used to evaluate the expression of TC, TG, LDL-C, hs-CRP, IL-6, IL-10, TNF-α, and SAA. Immunohistochemistry, reverse transcription quantitative polymerase chain reaction and Western blotting were used for expression of VEGF, MAPK8, WNT1, ß-catenin, GSK-3ß, p-GSK-3ß, CyclinD1, MMP-9, IL-6, and IL-8. MTT assay and flow cytometry for cell proliferation and apoptosis. Compared with the control group, other groups had lower levels of SBP, DBP, MBP, LVSP, and miR-330, higher levels of HR, LVEDP, TC, TG, LDC-C, hs-CRP, IL-6, IL-10, TNF-α, SAA, higher positive protein expression rates of MAPK8, VEGF, and MMP-9, elevated WNT1, ß-catenin, GSK-3ß and CyclinD1, and reduced cell proliferation. MAPK8-3'-UTR was targeted by miR-330. Compared with the blank group, the miR-330 mimic and DDK-1 groups had higher levels of SBP, DBP, MBP, LVSP, lower levels of HR, LVEDP, TC, TG, LDC-C, hs-CRP, IL-6, TNF-α, SAA, elevated IL-10, decreased positive protein expression rates of MAPK8 and VEGF, raised cell proliferation and reduced cell apoptosis rates. We conclude that overexpressed miR-330 suppresses atherosclerotic plaques formation while promotes VE cell proliferation by targeting MAPK8 through the WNT signaling pathway in ACS rats.

Pattern of initiation of monomorphic ventricular tachycardia and implications on tachycardia mechanism.

The incidence of sudden cardiac death, predominantly caused by ventricular tachycardia and ventricular fibrillation, is high in patients with congestive heart failure. Implantable cardiac defibrillators have improved survival in this population but defibrillator shocks can lead to low quality of life and heart failure progression. The current management of recurrent ventricular tachycardia includes ablation and anti-arrhythmic drugs and both are associated with high recurrence rates. Better understanding the mechanism of ventricular tachycardia allowing individualization of treatment may improve outcomes. Re-entry is currently accepted as the mechanism of the majority of monomorphic ventricular tachycardias in patients with congestive heart failure, being responsible for more than 90% of the ventricular tachycardia in patients with ischemic cardiomyopathy. On the other hand, some studies show a greater participation of focal arrhythmias in the genesis of ventricular tachycardia in this population. The pattern of initiation of ventricular tachycardia is divided into sudden, when the first beat of the tachycardia is morphologically similar to the rest of the tachycardia, and non-sudden, when its morphology is dissimilar. An association between the pattern of the initiation and the mechanism of ventricular tachycardia has been proposed. The pattern of initiation of ventricular tachycardia is a readily available from data stored in current generation implantable cardiac defibrillators. The association with tachycardia mechanism may allow individualization of the therapy, however evidence is lacking and further research is required.

Adaptation to second order stimulus features by electrosensory neurons causes ambiguity.

Understanding the coding strategies used to process sensory input remains a central problem in neuroscience. Growing evidence suggests that sensory systems process natural stimuli efficiently by ensuring a close match between neural tuning and stimulus statistics through adaptation. However, adaptation causes ambiguity as the same response can be elicited by different stimuli. The mechanisms by which the brain resolves ambiguity remain poorly understood. Here we investigated adaptation in electrosensory pyramidal neurons within different parallel maps in the weakly electric fish Apteronotus leptorhynchus. In response to step increases in stimulus variance, we found that pyramidal neurons within the lateral segment (LS) displayed strong scale invariant adaptation whereas those within the centromedial segment (CMS) instead displayed weaker degrees of scale invariant adaptation. Signal detection analysis revealed that strong adaptation in LS neurons significantly reduced stimulus discriminability. In contrast, weaker adaptation displayed by CMS neurons led to significantly lesser impairment of discriminability. Thus, while LS neurons display adaptation that is matched to natural scene statistics, thereby optimizing information transmission, CMS neurons instead display weaker adaptation and would instead provide information about the context in which these statistics occur. We propose that such a scheme is necessary for decoding by higher brain structures.

Temporal decorrelation by SK channels enables efficient neural coding and perception of natural stimuli.

It is commonly assumed that neural systems efficiently process natural sensory input. However, the mechanisms by which such efficient processing is achieved, and the consequences for perception and behaviour remain poorly understood. Here we show that small conductance calcium-activated potassium (SK) channels enable efficient neural processing and perception of natural stimuli. Specifically, these channels allow for the high-pass filtering of sensory input, thereby removing temporal correlations or, equivalently, whitening frequency response power. Varying the degree of adaptation through pharmacological manipulation of SK channels reduced efficiency of coding of natural stimuli, which in turn gave rise to predictable changes in behavioural responses that were no longer matched to natural stimulus statistics. Our results thus demonstrate a novel mechanism by which the nervous system can implement efficient processing and perception of natural sensory input that is likely to be shared across systems and species.

Identification of hub genes of pneumocyte senescence induced by thoracic irradiation using weighted gene co­expression network analysis.

Irradiation commonly causes pneumocyte senescence, which may lead to severe fatal lung injury characterized by pulmonary dysfunction and respiratory failure. However, the molecular mechanism underlying the induction of pneumocyte senescence by irradiation remains to be elucidated. In the present study, weighted gene co­expression network analysis (WGCNA) was used to screen for differentially expressed genes, and to identify the hub genes and gene modules, which may be critical for senescence. A total of 2,916 differentially expressed genes were identified between the senescence and non­senescence groups following thoracic irradiation. In total, 10 gene modules associated with cell senescence were detected, and six hub genes were identified, including B­cell scaffold protein with ankyrin repeats 1, translocase of outer mitochondrial membrane 70 homolog A, actin filament­associated protein 1, Cd84, Nuf2 and nuclear factor erythroid 2. These genes were markedly associated with cell proliferation, cell division and cell cycle arrest. The results of the present study demonstrated that WGCNA of microarray data may provide further insight into the molecular mechanism underlying pneumocyte senescence.

Identification of specific gene modules in mouse lung tissue exposed to cigarette smoke.

BACKGROUND: Exposure to cigarette may affect human health and increase risk of a wide range of diseases including pulmonary diseases, such as chronic obstructive pulmonary disease (COPD), asthma, lung fibrosis and lung cancer. However, the molecular mechanisms of pathogenesis induced by cigarettes still remain obscure even with extensive studies. With systemic view, we attempted to identify the specific gene modules that might relate to injury caused by cigarette smoke and identify hub genes for potential therapeutic targets or biomarkers from specific gene modules. MATERIALS AND METHODS: The dataset GSE18344 was downloaded from the Gene Expression Omnibus (GEO) and divided into mouse cigarette smoke exposure and control groups. Subsequently, weighted gene co-expression network analysis (WGCNA) was used to construct a gene co-expression network for each group and detected specific gene modules of cigarette smoke exposure by comparison. RESULTS: A total of ten specific gene modules were identified only in the cigarette smoke exposure group but not in the control group. Seven hub genes were identified as well, including Fip1l1, Anp32a, Acsl4, Evl, Sdc1, Arap3 and Cd52. CONCLUSIONS: Specific gene modules may provide better understanding of molecular mechanisms, and hub genes are potential candidates of therapeutic targets that may possible improve development of novel treatment approaches.

Overexpression of miRNA-21 promotes radiation-resistance of non-small cell lung cancer.

BACKGROUND: MiRNA-21 was previously reported to be up-regulated in many kinds of cancer. In the present study, we want to investigate the potential role of miRNA-21 in non-small cell lung cancer. MATERIALS AND METHODS: Expression of miRNA-21 was detected in 60 non-small cell lung cancer (NSCLC) samples and adjacent histologically normal tissue using RT-qPCR, Correlation between miRNA-21 expression and clinicopathological features of NSCLC was analyzed using statistical software. The effect of miRNA-21 expression on the growth and apoptosis of A549 cells induced by irradiation was examined. RESULTS: miRNA-21 expression increased in non-small cell lung cancer. Expression of miRNA-21 was positively associated with lymph node metastasis, clinical stage and poor prognosis. Multivariate Cox regression analysis showed that miRNA-21 was an independent prognostic factor for patients. Down-regulation of miRNA-21 inhibited proliferation and cell cycle progress of A549 cells and sensitized cells to radiation. Decreased miRNA-21 expression promoted the apoptosis of A549 cells induced by irradiation. CONCLUSIONS: miRNA-21 may be considered as a potential novel target for future development of specific therapeutic interventions in NSCLC.

Increased miRNA-22 expression sensitizes esophageal squamous cell carcinoma to irradiation.

miRNA-22 was previously reported to be a tumor suppressor. The aim of this study was to explore the expression and function of miRNA-22 in esophageal squamous cell carcinoma (ESCC). Expression of miRNA-22 in 100 ESCC tissues was examined by q-PCR. The correlation between miRNA-22 level and clinicopathological features was analyzed using SPSS16.0 statistical software. Moreover, the effect of miRNA-22 expression on radiosensitivity of ESCC cells was examined. miRNA-22 expression decreased in ESCC tissues, and statistical analyses showed that the expression of miRNA-22 was associated with the stage of clinical classification. No correlation was found between miRNA-22 expression and the overall survival of ESCC patients. However, significant positive correlation was found between miRNA-22 expression and the survival of patients who received radiotherapy (P < 0.05). Increased expression of miRNA-22 sensitized ESCC cells to γ-ray radiation and promoted the apoptosis of ESCC cells induced by γ-ray radiation. Increased expression level of miRNA-22 had effects on Rad51 expression after irradiation. These results demonstrate for the first time that decreased miRNA-22 expression correlates with increased radiotherapy resistance of ESCC, and that this effect is mediated, at least in part, by the Rad51 pathway.