Synthesis, characterization and antibacterial investigation of silver-copper nanoalloys

Cataloged from PDF version of article.Ag-Cu nanoalloys were synthesized by chemical co-reduction of their metal salts in aqueous solution with hydrazine hydrate, in the presence of complexing agent and stabilizer, preventing the oxidation of copper, as revealed by XPS. Their antibacterial behavior was tested against Escherichia coli strains, attesting far better ability of the Ag-Cu compared to Ag-only nanoparticles. © 2011 The Royal Society of Chemistry

Relative expression of rRNA transcripts and 45S rDNA promoter methylation status are dysregulated in tumors in comparison with matched-normal tissues in breast cancer

Ribosomal RNA (rRNA) expression, one of the most important factors regulating ribosome production, is primarily controlled by a CG-rich 45S rDNA promoter. However, the DNA methylation state of the 45S rDNA promoter, as well as its effect on rRNA gene expression in types of human cancers is controversial. In the present study we analyzed the methylation status of the rDNA promoter (-380 to +53 bp) as well as associated rRNA expression levels in breast cancer cell lines and breast tumor-normal tissue pairs. We found that the aforementioned regulatory region was extensively methylated (74-96%) in all cell lines and in 68% (13/19 tumor-normal pairs) of the tumors. Expression levels of rRNA transcripts 18S, 28S, 5.8S and 45S external transcribed spacer (45S ETS) greatly varied in the breast cancer cell lines regardless of their methylation status. Analyses of rRNA transcript expression levels in the breast tumor and normal matched tissues showed no significant difference when normalized with TBP. On the other hand, using the geometric mean of the rRNA expression values (GM-rRNA) as reference enabled us to identify significant changes in the relative expression of rRNAs in the tissue samples. We propose GM-rRNA normalization as a novel strategy to analyze expression differences between rRNA transcripts. Accordingly, the 18S rRNA/GM-rRNA ratio was significantly higher whereas the 5.8S rRNA/GM-rRNA ratio was significantly lower in breast tumor samples than this ratio in the matched normal samples. Moreover, the 18S rRNA/GM-rRNA ratio was negatively correlated with the 45S rDNA promoter methylation level in the normal breast tissue samples, yet not in the breast tumors. Significant correlations observed between the expression levels of rRNA transcripts in the normal samples were lost in the tumor samples. We showed that the expression of rRNA transcripts may not be based solely on promoter methylation. Carcinogenesis may cause dysregulation of the correlation between spliced rRNA expression levels, possibly due to changes in rRNA processing, which requires further investigation

Synthesis, characterization and antibacterial investigation of silver-copper nanoalloys

Ag-Cu nanoalloys were synthesized by chemical co-reduction of their metal salts in aqueous solution with hydrazine hydrate, in the presence of complexing agent and stabilizer, preventing the oxidation of copper, as revealed by XPS. Their antibacterial behavior was tested against Escherichia coli strains, attesting far better ability of the Ag-Cu compared to Ag-only nanoparticles. © 2011 The Royal Society of Chemistry

TIMP-2 gene transfer by positively charged PEG-lated monosized polycationic carrier to smooth muscle cells

Remodeling of the extracellular matrix resulting from increased secretion of metalloproteinase enzymes is implicated in restenosis following balloon angioplasty. Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases play an essential role in both normal and pathological extracellular matrix degradation. Tissue inhibitor of matrix metalloproteinase- 2 is the most extensively studied tissue inhibitor of metalloproteinases inmyocardial tissue in animalmodels and clinical examples of cardiac disease; therefore it is selected for this study. Gene transfer of tissue inhibitor of matrix metalloproteinase-2 may have a therapeutic potential by inhibition of matrix metalloproteinase activity. We have used PEG-lated nanoparticles poly(St/PEG-EEM/DMAPM) which were synthesized previously in our laboratory. The nanoparticles, with an average size of 77.6 ± 2.05 nm with a zeta potential of +64. 4 ± 1.14 mVand 201.9 ± 1.83 nmwith +54.2 ± 0.77 mV were used in the transfection studies. Zeta Potential values and size of polyplex were appropriate for an effective transfection. TIMP-2 expression was detected by western blotting. Increased protein level in smoothmuscle cells according to non-transfected smooth muscle cells confirms the successful delivery and expression of the tissue inhibitor of matrix metalloproteinase- 2 gene with the non-viral vector transfection approach. © Springer Science+Business Media B.V. 2012

Differential expression patterns of metastasis suppressor proteins in basal cell carcinoma

Background: Basal cell carcinomas (BCCs) are common malignant skin tumors. Despite having a significant invasion capacity, they metastasize only rarely. Our aim in this study was to detect the expression patterns of the NM23-H1, NDRG1, E-cadherin, RHOGDI2, CD82/KAI1, MKK4, and AKAP12 metastasis suppressor proteins in BCCs. Methods: A total of 96 BCC and 10 normal skin samples were included for the immunohistochemical study. Eleven frozen BCC samples were also studied by quantitative real time polymerase chain reaction (qRT-PCR) to detect the gene expression profile. Results: NM23-H1 was strongly and diffusely expressed in all types of BCC. Significant cytoplasmic expression of NDRG1 and E-cadherin was also detected. However, AKAP12 and CD82/KAI1 expression was significantly decreased. The expressions of the other proteins were somewhere between the two extremes. Similarly, qRT-PCR analysis showed down-regulation of AKAP12 and up-regulation of NM23-H1 and NDRG1 in BCC. Morphologically aggressive BCCs showed significantly higher cytoplasmic NDRG1 expression scores and lower CD82/KAI1 scores than non-aggressive BCCs. Conclusion: The relatively preserved levels of NM23-H1, NDRG1, and E-cadherin proteins may have a positive effect on the non-metastasizing features of these tumors. © 2014 The International Society of Dermatology

The Ability to Generate Senescent Progeny as a Mechanism Underlying Breast Cancer Cell Heterogeneity

Background Breast cancer is a remarkably heterogeneous disease. Luminal, basal-like, "normal-like", and ERBB2+ subgroups were identified and were shown to have different prognoses. The mechanisms underlying this heterogeneity are poorly understood. In our study, we explored the role of cellular differentiation and senescence as a potential cause of heterogeneity. Methodology/Principal Findings A panel of breast cancer cell lines, isogenic clones, and breast tumors were used. Based on their ability to generate senescent progeny under low-density clonogenic conditions, we classified breast cancer cell lines as senescent cell progenitor (SCP) and immortal cell progenitor (ICP) subtypes. All SCP cell lines expressed estrogen receptor (ER). Loss of ER expression combined with the accumulation of p21Cip1 correlated with senescence in these cell lines. p21Cip1 knockdown, estrogen-mediated ER activation or ectopic ER overexpression protected cells against senescence. In contrast, tamoxifen triggered a robust senescence response. As ER expression has been linked to luminal differentiation, we compared the differentiation status of SCP and ICP cell lines using stem/progenitor, luminal, and myoepithelial markers. The SCP cells produced CD24+ or ER+ luminal-like and ASMA+ myoepithelial-like progeny, in addition to CD44+ stem/progenitor-like cells. In contrast, ICP cell lines acted as differentiation-defective stem/progenitor cells. Some ICP cell lines generated only CD44+/CD24-/ER-/ASMA- progenitor/stem-like cells, and others also produced CD24+/ER- luminal-like, but not ASMA+ myoepithelial-like cells. Furthermore, gene expression profiles clustered SCP cell lines with luminal A and "normal-like" tumors, and ICP cell lines with luminal B and basal-like tumors. The ICP cells displayed higher tumorigenicity in immunodeficient mice. Conclusions/Significance Luminal A and "normal-like" breast cancer cell lines were able to generate luminal-like and myoepithelial-like progeny undergoing senescence arrest. In contrast, luminal B/basal-like cell lines acted as stem/progenitor cells with defective differentiation capacities. Our findings suggest that the malignancy of breast tumors is directly correlated with stem/progenitor phenotypes and poor differentiation potential. © 2010 Mumcuoglu et al

A resampling-based meta-analysis for detection of differential gene expression in breast cancer

<p>Abstract</p> <p>Background</p> <p>Accuracy in the diagnosis of breast cancer and classification of cancer subtypes has improved over the years with the development of well-established immunohistopathological criteria. More recently, diagnostic gene-sets at the mRNA expression level have been tested as better predictors of disease state. However, breast cancer is heterogeneous in nature; thus extraction of differentially expressed gene-sets that stably distinguish normal tissue from various pathologies poses challenges. Meta-analysis of high-throughput expression data using a collection of statistical methodologies leads to the identification of robust tumor gene expression signatures.</p> <p>Methods</p> <p>A resampling-based meta-analysis strategy, which involves the use of resampling and application of distribution statistics in combination to assess the degree of significance in differential expression between sample classes, was developed. Two independent microarray datasets that contain normal breast, invasive ductal carcinoma (IDC), and invasive lobular carcinoma (ILC) samples were used for the meta-analysis. Expression of the genes, selected from the gene list for classification of normal breast samples and breast tumors encompassing both the ILC and IDC subtypes were tested on 10 independent primary IDC samples and matched non-tumor controls by real-time qRT-PCR. Other existing breast cancer microarray datasets were used in support of the resampling-based meta-analysis.</p> <p>Results</p> <p>The two independent microarray studies were found to be comparable, although differing in their experimental methodologies (Pearson correlation coefficient, R = 0.9389 and R = 0.8465 for ductal and lobular samples, respectively). The resampling-based meta-analysis has led to the identification of a highly stable set of genes for classification of normal breast samples and breast tumors encompassing both the ILC and IDC subtypes. The expression results of the selected genes obtained through real-time qRT-PCR supported the meta-analysis results.</p> <p>Conclusion</p> <p>The proposed meta-analysis approach has the ability to detect a set of differentially expressed genes with the least amount of within-group variability, thus providing highly stable gene lists for class prediction. Increased statistical power and stringent filtering criteria used in the present study also make identification of novel candidate genes possible and may provide further insight to improve our understanding of breast cancer development.</p

In vitro antibacterial activities of erythromycin, clarithromycin, azithromycin and cephradine against methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains

The in vitro antibacterial activities of erythromycin, clarithromycin, and azithromycin were evaluated against 75 methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains isolated from the hospital and outpatient clinics by the broth microdilution method and these activities were compared with those of cephradine. Of these strains, 35 (47%) were isolated from in-patients and 40 (53%) from out-patients. A total of 19 (54.3%) of the hospital and 16 (40%) of the outpatient-clinic isolates were resistant to methicillin as determined by the disc diffusion method. Of the methicillin-sensitive hospital isolates, 75% were also susceptible to erythromycin, clarithromycin, and azithromycin (MIC range 0.25-64 μg/ ml), and 68.7% were susceptible to cephradine. For the strains (methicillin-resistant and methicillin-sensitive) that were isolated from outpatient clinics, the overall sensitivity rates were not statistically different, although the MIC values were lower for all the agents tested when compared with hospital isolates

Modulation of nitric oxide response by fluoroquinolones

In this study, we examined the effects of fluoroqinolones, namely ciprofloxacin (CIP) and ofloxacin (OFX) on nitric oxide (NO) production in an in vitro lipopolysaccharide(LPS)-activated macrophage model. Thioglycollate-elicited;ed peritoneal cells from BALB/c mice were exposed to varying concentrations of CIP and OFX for 1 or 4 days before LPS stimulation. NO response was measured by nitrite accumulation. On the first day of antibiotic exposure, nitrite production after LPS stimulation (1 mu g/ml) decreased by 49.3% (p0.05) and by 29.7% (p0.05) in the presence of 1 mM, 100 mu M and 10 mu M CIP and OFX, respectively. The inhibitory effects did not change significantly after 4 days' of exposure. The results indicate that, in this in vitro murine macrophage model, fluoroquinolones inhibit nitrite production in a dose-dependent manner and may have similar immunomodulatory effects in vivo