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

Cloning of Oct3/4 gene in embryonic stem cells

      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

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 H19→EZH2→p21/PTEN pathway by VPA treatment suggests

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

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

Effect of valproic acid on cisplatin-resistant ovarian cancer cell lines

Background and aims: Platinum resistance has been one of the most important problems in the management of ovarian cancer. The effects of various chemotherapeutic agents are limited in patients with platinum resistance. Therefore, developing new anticancer drugs that can improve the effect of currently used cytostatics is critical. The current study investigated the effects of valproic acid (VPA) alone and in combination with cisplatin on ovarian cancer cells. Methods: In this experimental study, the human ovarian cancer cell lines (A2780-S and A2780-CP) were grown in RPMI-1640 medium in appropriate culture conditions. The cells were treated with various concentrations of cisplatin (0.15-400 µg/mL) or VPA (10-2000 µg/mL) and were incubated for 24, 48, and 72 hours. Moreover, A2780 cells were co-treated with different concentrations of cisplatin and VPA for 48 hours. Afterward, cell viability was investigated using MTT assay. GraphPad Prism statistical software was used for the data analysis and ANOVA and Duncan’s test were conducted. Results: A dose- and time-dependent reduction was observed in cell viability following the treatment with cisplatin or VPA. Moreover, cotreatment of the A2780 cells with cisplatin and VPA resulted in a significantly greater inhibition of cell viability compared to the treatment with either agent alone. Conclusion: Overall, it can be argued that VPA does not only cause inhibition of proliferation and induction of apoptosis in ovarian cancer cells but also helps to enhance the antiproliferative effects of cisplatin and results in the increased susceptibility to cisplatin in resistant cells. VPA may therefore be used to treat cancer in the future. Keywords: Ovarian cancer, Cisplatin, Valproic acid, Platinum resistance, Antiproliferative effec

Metformin inhibits gastric cancer cells metastatic traits through suppression of epithelial-mesenchymal transition in a glucose-independent manner.

Epithelial-mesenchymal transition (EMT), which is mainly recognized by upregulation of mesenchymal markers and movement of cells, is a critical stage occurred during embryo development and spreading cancerous cells. Metformin is an antidiabetic drug used in treatment of type 2 diabetes. EMT inhibitory effect of metformin has been studied in several cancers; however, it remains unknown in gastric cancer. The aim of the present study was to investigate the metformin effects on inhibition of EMT-related genes as well as migration and invasion of AGS gastric cancer cell line. Moreover, to study the effect of glucose on metformin-mediated EMT inhibition, all experiments were performed in two glucose levels, similar to non-fasting blood sugar (7.8 mM) and hyperglycemic (17.5 mM) conditions. The results showed reduction of mesenchymal markers, including vimentin and β-catenin, and induction of epithelial marker, E-cadherin, by metformin in both glucose concentrations. Furthermore, wound-healing and invasion assays showed a significant decrease in cell migration and invasion after metformin treatment in both glucose levels. In conclusion, our results indicated that metformin strongly inhibited EMT of gastric cancer cells in conditions mimicking normo and hyperglycemic blood sugar

Glucose effects on metformin-inhibited cell invasion.

<p><b>(</b>A & B) AGS cells were treated with metformin for 24 hours and the cell invasion was measured in the Culturex 96 well BME invasion assay kit by counting the number of cells invading underside of BME (*<i>p</i> ≤ 0.01, **<i>p</i> ≤ 0.001 and ***<i>p</i> ≤ 0.0001). (C) Effect of high- and low-glucose media on cell invasion analyzed by JMP and levels not connected by same letter are significantly different (<i>p</i> ≤ 0.05).</p