131 research outputs found
COMPARISON OF THE CYTOTOXIC EFFECTS OF UMBELLIPRENIN AND AURAPTENE
Umbelliprenin and auraptene structurally belong to the class of coumarins. Umbelliprenin can be synthesized chemically or extracted by maceration at room temperature. Various biological effects for both umbel lip renin and auraptene have been reported. One of their most important effects is cytotoxicity. This finding has increased interest in the application of umbelliprenin and auraptene as novel chemotherapeutic agents. In several studies, umbelliprenin and auraptene were successfully evaluated for anti-cancer effect. Moreover, mechanistic studies have attempted to find the mechanism of action of umbelliprenin and auraptene. In this review, we describe the cytotoxic effects of umbelliprenin and auraptene and compare them with each other. Umbelliprenin and auraptene share some cytotoxic and apoptotic induction properties but have differences in the suggested mechanisms.Ć
MiR-221/222 promote chemoresistance to cisplatin in ovarian cancer cells by targeting PTEN/PI3K/AKT signaling pathway.
Cisplatin resistance is one of the main limitations in the treatment of ovarian cancer, and its mechanism has not been fully understood. The objectives of this study were to determine the role of miR-221/222 and its underlying mechanism in chemoresistance of ovarian cancer. We demonstrated that miR-221/222 expression levels were higher in A2780/CP cells compared with A2780 S cells. An in vitro cell viability assay showed that downregulation of miR-221/222 sensitized A2780/CP cells to cisplatin-induced cytotoxicity. Moreover, we found that knockdown of miR-221/222 by its specific inhibitors promoted the cisplatin-induced apoptosis in A2780/CP cells. Using bioinformatic analysis and luciferase reporter assay, miR-221/222 were found to directly target PTEN. Moreover, knockdown of miR-221/222 in A2780/CP cells significantly upregulated PTEN and downregulated PI3KCA and p-Akt expression. In conclusion, our results demonstrated that miR-221/222 induced cisplatin resistance by targeting PTEN mediated PI3K/Akt pathway in A2780/CP cells, suggesting that miR-221/222/PTEN/PI3K/Akt may be a promising prognostic and therapeutic target to overcome cisplatin resistance and treat ovarian cancer in the future
Dynamics of neural fields with exponential temporal kernel
Various experimental methods of recording the activity of brain tissue in
vitro and in vivo demonstrate the existence of traveling waves. Neural field
theory offers a theoretical framework within which such phenomena can be
studied. The question then is to identify the structural assumptions and the
parameter regimes for the emergence of traveling waves in neural fields. In
this paper, we consider the standard neural field equation with an exponential
temporal kernel. We analyze the time-independent (static) and time-dependent
(dynamic) bifurcations of the equilibrium solution and the emerging
Spatio-temporal wave patterns. We show that an exponential temporal kernel does
not allow static bifurcations such as saddle-node, pitchfork, and in
particular, static Turing bifurcations, in contrast to the Green's function
used by Atay and Hutt (SIAM J. Appl. Math. 65: 644-666, 2004). However, the
exponential temporal kernel possesses the important property that it takes into
account the finite memory of past activities of neurons, which the Green's
function does not. Through a dynamic bifurcation analysis, we give explicit
Hopf (temporally non-constant, but spatially constant solutions) and
Turing-Hopf (spatially and temporally non-constant solutions, in particular
traveling waves) bifurcation conditions on the parameter space which consists
of the coefficient of the exponential temporal kernel, the transmission speed
of neural signals, the time delay rate of synapses, and the ratio of excitatory
to inhibitory synaptic weights.Comment: 25 pages, 8 Figures, 44 Reference
Cloning of Oct3/4 gene in embryonic stem cells
Ā Ā Ā Ā Ā Embryonic stem cells (ESCs) are pluripotent, self-renewing cells. These cells can be used in applications such as cell therapy, drug discovery, disease modelling, and the study of cellular differentiation. In this experimental study embryonic stem cells cultured in the laboratory and were amplified. Total RNA was extracted from cells and converted to cDNA. The replication factor Oct3/4 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into the pTZ57R/T vector. Legated product had been transformed into susceptible bacteria and transformed bacteria were screened on a selective medium. Plasmids extracted from bacteria and enzyme digestion to confirm the sequencing was performed. Results of enzyme digestion were sequenced. Cloned gene can prepare a gene cassette to produce stem cells from somatic cell
Evaluation of RANKL/OPG Serum Concentration Ratio as a New Biomarker for Coronary Artery Calcification: A Pilot Study
Objective. There is a strong need for biomarkers to identify patients at risk for future cardiovascular events related with progressive atherosclerotic disease. Osteoprotegerin (OPG) protects the skeleton from excessive bone resorption by binding to receptor activator of nuclear factor-ĪŗB ligand (RANKL) and preventing it from binding to its receptor, receptor activator of nuclear factor-ĪŗB. However, conflicting results have been obtained about association of serum level of OPG or RANKL with coronary artery disease (CAD). Based on their role in inflammation and matrix degradation and the fact that atherosclerotic plaque formation is an inflammatory process, we hypothesized that RANKLā:āOPG ratio could be a better biomarker for CAD. Methods. In this cross-sectional study, the correlation between RANKLā:āOPG ratio serum concentration and coronary artery calcification (CAC) in 50 patients with ischemic coronary disease has been investigated. We used ELISA method for measuring RANKL and OPG serum concentrations. Results. There was a significant correlation between RANKLā:āOPG serum concentration ratio and CAC in our study population (P = 0.01). Conclusion. Our results suggested that RANKLā:āOPG ratio concentration has a potential of being used as a marker for coronary artery disease
Valproic Acid Promotes Apoptosis and Cisplatin Sensitivity Through Downregulation of H19 Noncoding RNA in Ovarian A2780 Cells
Abstract Cisplatin resistance is one of the main limitations in the treatment of ovarian cancer,
which is partly mediated by long noncoding RNAs (lncRNAs). H19 is a lncRNA involving in
cisplatin resistance in cancers. Valproic acid (VPA) is a commonly used drug for clinical
treatment of seizure disorders. In addition, this drug may display its effects through regulation
of noncoding RNAs controlling gene expression. The aim of the present study was the
investigation of VPA treatment effect on H19 expression in ovarian cancer cells and also the
relation of the H19 levels with apoptosis and cisplatin resistance. Briefly, treatment with VPA
not only led to significant increase in apoptosis rate, but also increased the cisplatin sensitivity
of A2780/CP cells. We found that following VPA treatment, the expression of H19 and EZH2
decreased, but the expression of p21 and PTEN increased significantly. To investigate the
involvement of H19 in VPA-induced apoptosis and cisplatin sensitivity, H19 was inhibited by
a specific siRNA. Our results demonstrate that H19 knockdown by siRNA induced apoptosis
and sensitized the A2780/CP cells to cisplatin-induced cytotoxicity. These data indicated that
VPA negatively regulates the expression of H19 in ovarian cancer cells, which subsequently
leads to apoptosis induction, cell proliferation inhibition, and overwhelming to cisplatin
resistance. The implication of H19āEZH2āp21/PTEN pathway by VPA treatment suggests
The role of metalloproteinase and hypoxia conditions in endometrial cells and embryo implantation
In the process of implantation, metalloproteinase enzymes play a key role in basement membrane degradation and endometrial extracellular matrix. The activity of these enzymes is impeded by binding Tissue Inhibitors of Metalloproteinase (TIMP). The oxygen concentration in the mammalian uterus at the time of implantation is about 2-5%. It is seen that the imposition of hypoxia on cancer cells increases the expression of metalloproteinase enzymes and reduces the expression of metalloproteinase inhibitors, resulting in increased cell invasion. To know the effect of Hypoxia-Inducible Factor (HIF) and other related factors, we decided to evaluate hypoxic conditions on endometrial epithelial cells of the uterus and roll of matrix metalloproteinases (MMPs) on angiogenesis and invasion of the embryo during implantation. In this study, human and mouse endometrial epithelial cells were incubated for 24-48 hours in hypoxic conditions. Subsequently, the expression level of TIMP-1 was measured in mouse and human epithelial cells by Real-Time PCR technique. The cell viability in hypoxic conditions was evaluated by MTT assay. Our results demonstrated that hypoxia reduced the quantitative gene expression of TIMP-1 in the human and mouse endometrial epithelial cells compared to the control group. It can be concluded that applying hypoxic conditions by reducing the TIMP-1 expression and consequently increasing MMP expression, may improve the embryo implantation rate
Comparative study of methods for extraction and purification of environmental DNA from high-strength wastewater sludge
DNA extraction from wastewater sludge (COD 50000 and BOD 25000 mg/l) was conducted using nine different methods normally used for environmental samples including a procedure used in this study and the results obtained were compared. The quality of the differently extracted DNAs was subsequently assessed by measuring humic acid concentration, cell lysis efficiency, polymerase chain reaction (PCR) amplification of methanogenic and eubacterial 16S rDNA. The protocol developed in this study was further evaluated by extracting DNA from various high-strength wastewater sludge samples, denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) analyses. The results revealed that great differences existed among the nine procedures and only a few produced satisfactory results when applied to high-strength wastewater sludge. Thermal shock alone was shown inefficient to disrupt the methanogenic cell wall to release the DNA. The method presented in this study (Procedure 9) is generally recommended because of the low concentration of contaminants and its high efficiency despite its simplicity.Key words: High-strength wastewater sludge, DNA extraction, environmental samples, humic acids, denaturing gradient gel electrophoresis, fluorescent in situ hybridizatio
Comparative study of methods for extraction and purification of environmental DNA from high-strength wastewater sludge
DNA extraction from wastewater sludge (COD 50000 and BOD 25000 mg/l) was conducted using nine different methods normally used for environmental samples including a procedure used in this study and the results obtained were compared. The quality of the differently extracted DNAs was subsequently assessed by measuring humic acid concentration, cell lysis efficiency, polymerase chain reaction (PCR) amplification of methanogenic and eubacterial 16S rDNA. The protocol developed in this study was further evaluated by extracting DNA from various high-strength wastewater sludge samples, denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) analyses. The results revealed that great differences existed among the nine procedures and only a few produced satisfactory results when applied to high-strength wastewater sludge. Thermal shock alone was shown inefficient to disrupt the methanogenic cell wall to release the DNA. The method presented in this study (Procedure 9) is generally recommended because of the low concentration of contaminants and its high efficiency despite its simplicity
Elevating the expression level of biologically active recombinant human alpha 1-antitrypsin in Pichia pastoris
Background: Human alpha 1-antitrypsin (AAT) is a potent inhibitor of
multiple serine proteases, and protects tissues against their harmful
effects. Individuals with reduced or abnormal production of this
inhibitor need intravenous administration of exogenous protein. In this
study, we employed the methylotrophic (methanol utilizing) yeast Pichia
pastoris (P. pastoris) as a preferential host for efficient
production and secretion of recombinant AAT. Furthermore, we examined
different strategies to maximize the yield of the secreted protein.
Results: Our findings revealed that optimizing the codon usage of AAT
gene for P. pastoris had positive effects on the level of secreted AAT
under the control of inducible alcohol oxidase 1 (AOX1) and
constitutive glycerol aldehyde phosphate dehydrogenase (GAP) promoters.
Compared to AOX1, the GAP promoter increased the yield of AAT by more
than two fold. It was also demonstrated that the human AAT native
signal sequence was more effective than the well-known yeast signal
sequence, alpha mating factor (\u3b1-MF). Doubling gene dosage nearly
doubled the production of AAT, though dosages exceeding this limit had
negative effects on the yield. Conclusion: P. pastoris is shown to be
an efficient expression system for production of recombinant and
biologically active AAT. Also different strategies could be used to
elevate the amount of this secretable protein
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