Gap Junctions: The Claymore for Cancerous Cells

Introduction: Gap junctions play an important role in the cell proliferation in mammalian cells as well as carcinogenesis. However, there are controversial issues about their role in cancer pathogenesis. This study was designed to evaluate genotoxicity and cytotoxicity of Carbenoxolone (CBX) as a prototype of inter-cellular gap junction blocker in MCF7 and BT20 human breast cancer cells. Methods: The MCF7and BT20 human breast cancer cell lines were cultivated, and treated at designated confluency with different doses of CBX. Cellular cytotoxicity was examined using standard colorimetric assay associated with cell viability tests. Gene expression evaluation was carried out using real time polymerase chain reaction (PCR). Results: MCF7 and BT20 cells were significantly affected by CBX in a dose dependent manner in cell viability assays. Despite varying expression of genes, down regulation of pro- and anti-apoptotic genes was observed in these cells. Conclusion: Based upon this investigation, it can be concluded that CBX could affect both low and high proliferative types of breast cancer cell lines and disproportionate down regulation of both pre- and anti-apoptotic genes may be related to interacting biomolecules, perhaps via gap junctions

Nanoscaled aptasensors for multi-analyte sensing

Introduction: Nanoscaled aptamers (Aps), as short single-stranded DNA or RNA oligonucleotides, are able to bind to their specific targets with high affinity, upon which they are considered as powerful diagnostic and analytical sensing tools (the so-called "aptasensors"). Aptamers are selected from a random pool of oligonucleotides through a procedure known as "systematic evolution of ligands by exponential enrichment". Methods: In this work, the most recent studies in the field of aptasensors are reviewed and discussed with a main focus on the potential of aptasensors for the multi-analyte detection(s). Results: Due to the specific folding capability of aptamers in the presence of analyte, aptasensors have substantially successfully been exploited for the detection of a wide range of small and large molecules (e.g., drugs and their metabolites, toxins, and associated biomarkers in various diseases) at very low concentrations in the biological fluids/samples even in presence of interfering species. Conclusion: Biological samples are generally considered as complexes in the real biological media. Hence, the development of aptasensors with capability to determine various targets simultaneously within a biological matrix seems to be our main challenge. To this end, integration of various key scientific dominions such as bioengineering and systems biology with biomedical researches are inevitable

Citoprotektivni učinci silafibrata, novosintetiziranog silikoniranog derivata klofibrata protiv acetaminofenom izazvane toksičnosti u izoliranim hepatocitima štakora

Acetaminophen (N-acetyl para amino phenol, APAP) is a widely used antipyretic and analgesic drug responsible for various drug-induced liver injuries. This study evaluated APAP-induced toxicity in isolated rat hepatocytes alongside the protective effects of silafibrate and N-acetyl cysteine (NAC). Hepatocytes were isolated from male Sprague-Dawley rats by collagenase enzyme perfusion via the portal vein. This technique is based on liver perfusion with collagenase after removing calcium ions (Ca2+) with a chelator. Cells were treated with different concentrations of APAP, silafibrate, and NAC. Cell death, reactive oxygen species (ROS) formation, lipid peroxidation, and mitochondrial depolarisation were measured as toxicity markers. ROS formation and lipid peroxidation occurred after APAP administration to rat hepatocytes. APAP caused mitochondrial depolarisation in isolated cells. Administration of silafibrate (200 μmol L-1) and/or NAC (200 μmol L-1) reduced the ROS formation, lipid peroxidation, and mitochondrial depolarisation caused by APAP. Cytotoxicity induced by APAP in rat hepatocytes was mediated by oxidative stress. In addition, APAP seemed to target cellular mitochondria during hepatocyte damage. The protective properties of silafibrate and/or NAC against APAP‑induced hepatic injury may have involved the induction of antioxidant enzymes, protection against oxidative stress and inflammatory responses, and alteration in cellular glutathione content.Acetaminofen (N-acetil-para-aminofenol, APAP) često je korišteni antipiretik i analgetik koji može izazvati oštećenja jetara. Na modelu izoliranih hepatocita štakora istražili smo toksične učinke APAP-a i protektivne učinke silafibrata i N-acetilcisteina (NAC). Hepatociti su izolirani iz mužjaka štakora soja Sprague-Dawley perfuzijom jetara i uvođenjem enzima kolagenaze putem portalne vene. Ta se tehnika zasniva na perfuziji jetara kolagenazom nakon uklanjanja kalcijevih iona (Ca2+) kelatorom. Stanice su tretirane različitim koncentracijama APAP-a, silafibrata i NAC-a. Kao markeri toksičnosti mjereni su smrt stanica, stvaranje reaktivnih kisikovih vrsta (ROS), lipidna peroksidacija i depolarizacija mitohondrija. Primjena APAP-a u štakora izazvala je stvaranje ROS-ova i lipidnu peroksidaciju. APAP je uzrokovao depolarizaciju mitohondrija u izoliranim stanicama. Primjena silafibrata (200 μmol L-1) i/ili NAC-a (200 μmol L-1) smanjila je stvaranje ROS-a, lipidnu peroksidaciju i depolarizaciju mitohondrija uzrokovanu APAP-om. Utvrdili smo da je citotoksičnost APAP-a posredovana oksidativnim stresom. Nadalje, čini se da su mitohondriji ciljni stanični organeli za oštećenja hepatocita izazvanih APAP-om. Moguće je da su protektivna svojstva silafibrata i/ili NAC-a protiv APAP‑om induciranog oštećenja jetara uključivala i indukciju antioksidacijskih enzima, zaštitu od oksidativnog stresa i upalnih odgovora te promjenu razine staničnoga glutationa

Identification and Functional Analysis of Inherited Variation in the CYP3A4 Gene Regulatory Region.

CYP3A4 is usually the major cytochrome P450 enzyme in adult human liver. It is known to metabolise a wide variety of xenobiotic and endogenous compounds. Substantial inter-individual variation in hepatic levels of CYP3A4 has been observed and although polymorphic mutations have been reported in both the 5' regulatory and coding regions of the CYP3A4 gene, those investigated so far do not appear to make a major contribution to CYP3A4 variation in the population as a whole. To determine whether regulatory mutations might occur in more distal regions of the promoter, I have performed a new population screening on a panel of 101 human DNA samples. 1141 bp of the proximal 5' regulatory region of the CYP3A4 gene and 300 bp of the distal enhancer region at -7. 9 kb, both containing numerous regulatory motifs, were amplified from genomic DNA. Screening for mutations in the resulting PCR products was carried out using non-radioactive single strand conformation polymorphism (SSCP) followed by confirmatory sequencing of both DNA strands. In addition to detection of the previously reported CYP3A4*1B allele in nine subjects, three novel alleles were found: CYP3A4*1E (having a T→A transversion at -369 in one subject), CYP3A4*1F (having a C→G transversion at -747 in 17 subjects) and CYP3A4*15B having a nine-nucleotide insertion between -845 and -844 linked to an A→G transition at -392 and a G→A transition in exon 6 (position 485 in the cDNA) in one subject. No mutations were found in the distal enhancer region indicating strong conservation of sequence in this region of the promoter. Functional analysis of the regulatory region mutants was performed in vitro using reporter DNA constructs in which the whole 1141 bp proximal promoter region from each mutant allele was inserted between a single copy of the 300 bp core distal enhancer sequence and the cDNA for human secreted alkaline phosphatase (SEAP). The individual reporter constructs were co-transfected with an hPXR expression vector into human liver (HepG2, HuH7) and intestinal (Caco-2) cell lines, in the presence or absence of classical xenobiotic inducers of CYP3A4. Modulation of transcriptional activation, as indicated by SEAP expression, was measured by chemiluminescent SEAP assay of the culture medium. Significant variation in promoter strength was found between the mutant CYP3A4 promoter alleles depending on the inducer used and the recipient cell line. While there was close similarity between the xenobiotic induction patterns for wild type and mutant promoters in HepG2 and HuH7 cells, the pattern in Caco-2 cells was substantially different. Identification of novel regulatory and coding region alleles of CYP3A4 will assist detailed investigation of the mechanistic basis of CYP3A4 regulation and help elucidate the relationship between genotype, xenobiotic metabolism and toxicity in the CYP3A family of isoenzymes

Identification and functional analysis of inherited variation in the CYP3A4 gene regulatory region

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN055109 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Study of Aptamer-Attached Juglone in Different pH Ranges and Ionic Concentrations of Buffers: Electrochemical aptamer-based sensors

Electrochemical aptamer-based sensors attract a lot of interest as useful methods because of their low cost, accuracy, sensitivity, and simplicity. An electro-active redox molecule comprises the main part of the electrochemical-based sensors. Ferrocene is one of the most popular redox molecule used in biosensor fabrication. But, instability of ferrocenium ion in strong nucleophilic reagents and chloride containingsolutions is one of the main problems of this redox molecule. In this study, Juglone is used as an effective quinone redox molecule for aptasensor designing in different pH ranges and different concentrations of chloride ion. The voltammetric studies showed that the electrochemical response of sensor increased by raising the buffer ionic concentration and the sensor accuracy in 7.0 to 8.0 pH range as well. Accordingto the findings, Juglone could be used as an effective redox molecule in high concentrations of chloride containing solutions in the 7.0 pH

A review of modeling techniques for genetic regulatory networks

Understanding the genetic regulatory networks, the discovery of interactions between genes and understanding regulatory processes in a cell at the gene level are the major goals of system biology and computational biology. Modeling gene regulatory networks and describing the actions of the cells at the molecular level are used in medicine and molecular biology applications such as metabolic pathways and drug discovery. Modeling these networks is also one of the important issues in genomic signal processing. After the advent of microarray technology, it is possible to model these networks using time-series data. In this paper, we provide an extensive review of methods that have been used on time-series data and represent the features, advantages and disadvantages of each. Also, we classify these methods according to their nature. A parallel study of these methods can lead to the discovery of new synthetic methods or improve previous methods

The Protective Effect of Garlic Extract againstAcetaminophen-Induced Loss of Mitochondrial MembranePotential in Freshly Isolated Rat Hepatocytes: Effect of garlic extract against acetaminophen cytotoxicity

Overdose of acetaminophen causes severe hepatic necrosis in humans and experimental animals. Studies on its hepatotoxicity remain a very active area since some of current data are still uncertain. In this study, freshly isolated rat hepatocytes were used to determine the effects of garlic extract and its component, allicin on the acetaminophen-induced cell cytotoxicity and to compare with the effect of N-acetyl cysteine as a standard treatment. Garlic extract was prepared via a standardmethod and its allicin and allyl mercaptan contents were determined using analytical and preparative high performance liquid chromatography (HPLC). Rat hepatocytes were isolated using collagenase perfusion and mitochondrial membrane potential and cell cytotoxicity were determined using Rhodamine 123 fluorescence and trypan blue exclusion, respectively. Inclusion of garlic extract and/or N-acetyl cysteine resulted in a reduction in the loss of mitochondrial membrane potential as well as cell death which occurred after acetaminophen addition and therefore,illustrated considerable hepatoprotective effects without significant differences between two treatments. In contrast, pure allicin was not effective significantly. The hepatoprotective effects of garlic extract may be due to the compounds other than allicin such as allyl mercaptan, as allicin has been shown to transform to allyl mercaptan as a major metabolite