402 research outputs found
Short-term calorie restriction ameliorates genomewide, age-related alterations in DNA methylation
DNA methylation plays major roles in many biological processes, including aging, carcinogenesis, and development. Analyses of DNA methylation using next-generation sequencing offer a new way to profile and compare methylomes across the genome in the context of aging. We explored genomewide DNA methylation and the effects of short-term calorie restriction (CR) on the methylome of aged rat kidney. Whole-genome methylation of kidney in young (6 months old), old (25 months old), and OCR (old with 4-week, short-term CR) rats was analyzed by methylated DNA immunoprecipitation and next-generation sequencing (MeDIP-Seq). CpG islands and repetitive regions were hypomethylated, but 5'-UTR, exon, and 3'-UTR hypermethylated in old and OCR rats. The methylation in the promoter and intron regions was decreased in old rats, but increased in OCR rats. Pathway enrichment analysis showed that the hypermethylated promoters in old rats were associated with degenerative phenotypes such as cancer and diabetes. The hypomethylated promoters in old rats related significantly to the chemokine signaling pathway. However, the pathways significantly enriched in old rats were not observed from the differentially methylated promoters in OCR rats. Thus, these findings suggest that short-term CR could partially ameliorate age-related methylation changes in promoters in old rats. From the epigenomic data, we propose that the hypermethylation found in the promoter regions of disease-related genes during aging may indicate increases in susceptibility to age-related diseases. Therefore, the CR-induced epigenetic changes that ameliorate age-dependent aberrant methylation may be important to CR's health-and life-prolonging effects.ope
The Pathogenetic Role of Reactive Oxygen Species in Aminonucleoside Nephrosis
We studied the pathogenetic role of reactive oxygen species (ROS) in
rats with puromycin aminonucleoside nephrosis (PAN). Heavy albuminuria with markedly
decreased density of the anionic sites (AS) on glomerular basement membrane
(GBM) (2. 6 Ā± O. 98 compared to 20. 0 Ā± 1. 61 AS/l,OOOnm GBM in control) developed
7 days after PA injection. The malondialdehyde (MDA) levels in kidney
homogenates increased gradually (1. 16 Ā± O. 18 at day -1 to 1. 97 Ā± O. 23/g protein
at day 5). While catalase or dimethyl sulfoxide, administered with PA, did not affect the
course of PAN. superoxide dismutase and allopurinol reduced proteinuria
and decreased loss of the AS (11. 7 Ā± 2. 80 and 13, 7 Ā± 1. 27 AS/l.000nm GBM, reo
spectively) at day 7. These findings suggest that proteinuria in PAN results from the
loss of GBM AS. in which ROS generated by xanthine oxidase system plays an import.
ant role
Improving gastric cancer preclinical studies using diverse in vitro and in vivo model systems
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the Creative Commons license, and indicate if changes were made.Abstract
Background
Biomarker-driven targeted therapy, the practice of tailoring patients treatment to the expression/activity levels of disease-specific genes/proteins, remains challenging. For example, while the anti-ERBB2 monoclonal antibody, trastuzumab, was first developed using well-characterized, diverse in vitro breast cancer models (and is now a standard adjuvant therapy for ERBB2-positive breast cancer patients), trastuzumab approval for ERBB2-positive gastric cancer was largely based on preclinical studies of a single cell line, NCI-N87. Ensuing clinical trials revealed only modest patient efficacy, and many ERBB2-positive gastric cancer (GC) patients failed to respond at all (i.e., were inherently recalcitrant), or succumbed to acquired resistance.
Method
To assess mechanisms underlying GC insensitivity to ERBB2 therapies, we established a diverse panel of GC cells, differing in ERBB2 expression levels, for comprehensive in vitro and in vivo characterization. For higher throughput assays of ERBB2 DNA and protein levels, we compared the concordance of various laboratory quantification methods, including those of in vitro and in vivo genetic anomalies (FISH and SISH) and xenograft protein expression (Western blot vs. IHC), of both cell and xenograft (tissue-sectioned) microarrays.
Results
The biomarker assessment methods strongly agreed, as did correlation between RNA and protein expression. However, although ERBB2 genomic anomalies showed good in vitro vs. in vivo correlation, we observed striking differences in protein expression between cultured cells and mouse xenografts (even within the same GC cell type). Via our unique pathway analysis, we delineated a signaling network, in addition to specific pathways/biological processes, emanating from the ERBB2 signaling cascade, as a potential useful target of clinical treatment. Integrated analysis of public data from gastric tumors revealed frequent (10 ā 20Ā %) amplification of the genes NFKBIE, PTK2, and PIK3CA, each of which resides in an ERBB2-derived subpathway network.
Conclusion
Our comprehensive bioinformatics analyses of highly heterogeneous cancer cells, combined with tumor omics profiles, can optimally characterize the expression patterns and activity of specific tumor biomarkers. Subsequent in vitro and in vivo validation, of specific disease biomarkers (using multiple methodologies), can improve prediction of patient stratification according to drug response or nonresponse
Upregulation of P21-Activated Kinase 1 (PAK1)/CREB Axis in Squamous Non-Small Cell Lung Carcinoma
Background/Aims: p21-activated Ser/Thr kinase 1 (PAK1) is essential for the genesis and development of many cancers. The purpose of this study was to investigate the role of the PAK1ācyclic AMP response element-binding (CREB) axis in non-small cell lung cancer (NSCLC) tumorigenesis and its related mechanisms. Methods: Western blot assay and immunohistochemical staining were employed to investigate the PAK1 and CREB expression in the tissue microarray of human squamous NSCLC. Co-immunoprecipitation and immunofluorescence confocal assays were performed to determine the link between PAK1 and CREB. NSCLC xenograft models were used to study oncogenic function of PAK1 in vivo. Results: We observed that PAK1 and CREB expression levels were significantly elevated in human squamous NSCLC-tissue specimens, compared with those in adjacent normal bronchial or bronchiolar epithelial-tissue specimens, as well as their phosphorylated forms, based on western blotting. We showed in vitro that PAK1 knockdown by small-interfering RNA (siRNA) blocked CREB phosphorylation, whereas plasmid-based PAK1 overexpression resulted in CREB phosphorylation at Ser133, based on western blotting. In addition, PAK1 interacted with CREB in co-immunoprecipitation assays. Additionally, our in vitro findings detected by flow cytometry revealed that PAK1 silencing attenuated cell cycle progression, inducing apoptosis. Inhibition of PAK1 expression reduced tumor sizes and masses by modulating CREB expression and activation in xenograft models. Conclusion: These results suggest a novel mechanism whereby the PAK1āCREB axis drives carcinogenesis of squamous-cell carcinomas, and have important implications in the development of targeted therapeutics for squamous-cell lung cancer
Intravenous fluid prescription practices among pediatric residents in Korea
PurposeRecent studies have established the association between hypotonic fluids administration and hospital-acquired hyponatremia in children. The present paper investigated the pattern of current practice in intravenous fluid prescription among Korean pediatric residents, to underscore the need for updated education.MethodsA survey-based analysis was carried out. Pediatric residents at six university hospitals in Korea completed a survey consisting of four questions. Each question proposed a unique scenario in which the respondents had to prescribe either a hypotonic or an isotonic fluid for the patient.ResultsNinety-one responses were collected and analyzed. In three of the four scenarios, a significant majority prescribed the hypotonic fluids (98.9%, 85.7%, and 69.2%, respectively). Notably, 69.2% of the respondents selected the hypotonic fluids for postoperative management. Almost all (96.7%) selected the isotonic fluids for hydration therapy.ConclusionIn the given scenarios, the majority of Korean pediatric residents would prescribe a hypotonic fluid, except for initial hydration. The current state of pediatric fluid management, notably, heightens the risk of hospital-acquired hyponatremia. Updated clinical practice education on intravenous fluid prescription, therefore, is urgently required
TRAF6 Mediates IL-1Ī²/LPS-Induced Suppression of TGF-Ī² Signaling through Its Interaction with the Type III TGF-Ī² Receptor
Transforming growth factor-Ī²1 (TGF-Ī²1) is an important anti-inflammatory cytokine that modulates and resolves inflammatory responses. Recent studies have demonstrated that inflammation enhances neoplastic risk and potentiates tumor progression. In the evolution of cancer, pro-inflammatory cytokines such as IL-1Ī² must overcome the anti-inflammatory effects of TGF-Ī² to boost pro-inflammatory responses in epithelial cells. Here we show that IL-1Ī² or Lipopolysaccharide (LPS) suppresses TGF-Ī²-induced anti-inflammatory signaling in a NF-ĪŗB-independent manner. TRAF6, a key molecule in IL-1Ī² signaling, mediates this suppressive effect through interaction with the type III TGF-Ī² receptor (TĪ²RIII), which is TGF-Ī²-dependent and requires type I TGF-Ī² receptor (TĪ²RI) kinase activity. TĪ²RI phosphorylates TĪ²RIII at residue S829, which promotes the TRAF6/TĪ²RIII interaction and consequent sequestration of TĪ²RIII from the TĪ²RII/TĪ²RI complex. Our data indicate that IL-1Ī² enhances the pro-inflammatory response by suppressing TGF-Ī²signaling through TRAF6-mediated sequestration of TĪ²RIII, which may be an important contributor to the early stages of tumor progression
Metabolic changes of salicylic acid-elicited Catharanthus roseus cell suspension cultures monitored by NMR-based metabolomics
The effect of salicylic acid (SA) on the metabolic profile of Catharanthus roseus suspension cells throughout a time course (0, 6, 12, 24, 48 and 72Ā h after treatment) was investigated using NMR spectroscopy and multivariate data analysis. When compared to control cell lines, SA-treated cells showed a high level of sugars (glucose and sucrose) up to 48Ā h after treatment, followed by a dynamic change in amino acids, phenylpropanoids, and tryptamine. Additionally, one compoundā2,5-dihydroxybenzoic-5-O-glucosideāwas detected solely in SA-treated cells
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