TGM2, HMGA2, FXYD3, and LGALS4 genes as biomarkers in acquired oxaliplatin resistance of human colorectal cancer: A systems biology approach

Acquired resistance to oxaliplatin is considered as the primary reason for failure in colorectal cancer (CRC) therapy. Identifying the underlying resistance mechanisms may improve CRC treatment. The present study aims to identify the key genes involved in acquired oxaliplatin-resistant in CRC by confirming the oxaliplatin resistance index (OX-RI). To this aim, two public microarray datasets regarding oxaliplatin-resistant CRC cells with different OX-RI, GSE42387, and GSE76092 were downloaded from GEO database to identify differentially expressed genes (DEGs). The results indicated that the OX-RI affects the gene expression pattern significantly. Then, 54 common DEGs in both datasets including 18 up- and 36 down-regulated genes were identified. Protein-protein interaction (PPI) analysis revealed 13 up- (MAGEA6, TGM2, MAGEA4, SCHIP1, ECI2, CD33, AKAP12, MAGEA12, CALD1, WFDC2, VSNL1, HMGA2, and MAGEA2B) and 12 down-regulated (PDZK1IP1, FXYD3, ALDH2, CEACAM6, QPRT, GRB10, TM4SF4, LGALS4, ALDH3A1, USH1C, KCNE3, and CA12) hub genes. In the next step, two novel up-regulated hub genes including ECI2 and SCHIP1 were identified to be related to oxaliplatin resistance. Functional enrichment and pathway analysis indicated that metabolic pathways, proliferation, and epithelial-mesenchymal transition may play dominant roles in CRC progression and oxaliplatin resistance. In the next procedure, two in vitro oxaliplatin-resistant sub-lines including HCT116/OX-R4.3 and HCT116/OX-R10 cells with OX-IR 3.93 and 10.06 were established, respectively. The results indicated the up-regulation of TGM2 and HMGA2 in HCT116/OX-R10 cells with high OX-RI and down-regulation of FXYD3, LGALS4, and ECI2 in both cell types. Based on the results, TGM2, HMGA2, FXYD3, and LGALS4 genes are related to oxaliplatin-resistant CRC and may serve as novel therapeutic targets.

Computational study of SENP1 in cancer by novel natural compounds and ZINC database screening

Introduction: Sentrin-specific protease 1 (SENP1) is a protein whose main function is deSUMOylation. SENP1 inhibits apoptosis, and increases angiogenesis, estrogen and androgen receptor transcription and c-Jun transcription factor, proliferation, growth, cell migration, and invasion of cancer. The in vivo and in vitro studies also demonstrated which natural compounds, especially phytochemicals, minerals, and vitamins, prevent cancer. More than 3,000 plant species have been reported in modern medicine. Natural compounds have many anti-cancerous andanti-turmeric properties such as antioxidative, antiangiogenic, antiproliferative, and pro-apoptotic properties. Methods: In this study, we investigated the interaction of some natural compounds with SENP1 to inhibit its activity. We also screened the ZINC database including natural compounds. Molecular docking was performed, and toxicity of compounds was determined; then, molecular dynamics simulation (MDS) and essential dynamics (ED) were performed on natural compounds with higher free binding energies and minimal side effects. By searching in a large library, virtual screening of the ZINC database was performed using LibDock and CDOCKER, and the final top 20 compounds were allowed for docking against SENP1. According to the docking study, the top three leading molecules were selected and further analyzed by MDS and ED. Results: The results suggest that resveratrol (from the selected compounds) and ZINC33916875 (from the ZINC database) could be more promising SENP1 inhibitory ligands. Discussion: Because these compounds can inhibit SENP1 activity, then they can be novel candidates for cancer treatment. However, wet laboratory experiments are needed to validate their efficacy as SENP1 inhibitors.

Study of DACH1 Expression and its Epigenetic Regulators as Possible Breast Cancer-Related Biomarkers

Background

Breast carcinogenesis involves both genetic and epigenetic changes. DNA methylation, as well as micro-RNA regulations, are the significant epigenetic phenomena dysregulated in breast cancer. Herein, the expression of DACH1 as a tumor suppressor gene and its promoter methylation status was analyzed in breast cancer tumors. Also, the expression of three micro RNAs (miR-217, miR-6807-3p, and miR-552), which had been previously reported to target DACH1, was assessed.

Methods

The SYBR green-based Real-Time reverse transcription-PCR was used to determine DACH1 and micro-RNAs (miR-217, miR-6807-3p, and miR-552) expression in 120 ductal breast cancer tumors compared with standard control. Also, the promoter methylation pattern of DACH1 was investigated using the Methylation-specific PCR technique.

Results

DACH1 expression was significantly down-regulated in breast tumors (p<0.05). About 33.5% of tumors showed DACH1 promoter hyper-methylation. The studied micro-RNAs, expression was negatively correlated with DACH1 expression. The highest expressions of miRNAs and higher DACH1 promoter methylation were observed in advanced cancer situations. The Kaplan-Meier survival curves indicated that the overall survival was significantly poor in higher miRNAs and lower DACH1 expression in breast cancer patients (p<0.002).

Conclusion

DACH1 down-regulation may be associated with a poor breast cancer prognosis. The DACH1 down-regulation may be due to epigenetic regulations such as promoter methylation, especially in triple-negative cases. Other factors, such as micro-RNAs (miR-217, miR-6807-3p, and miR-552), may also have an impact. The elevated expression of miR-217, miR-6807-3p, and miR-552, maybe candidates as possible poor prognostic biomarkers in breast cancer management for further consideration.

Potential antiviral activities of chrysin against hepatitis B virus

BACKGROUND

Interferon and nucleos(t)ide analogues are current therapeutic treatments for chronic Hepatitis B virus (HBV) infection with the limitations of a functional cure. Chrysin (5, 7-dihydroxyflavone) is a natural flavonoid, known for its antiviral and hepatoprotective activities. However, its anti-HBV activity is unexplored.

METHODS

In the present study, the anti-hepatitis B activity of chrysin was investigated using the in vitro experimental cell culture model, HepG2 cells. In silico studies were performed where chrysin and lamivudine (used here as a positive control) were docked with high mobility group box 1 protein (HMGB1). For the in vitro studies, wild type HBV genome construct (pHBV 1.3X) was transiently transfected in HepG2. In culture supernatant samples, HBV surface antigen (HBsAg) and Hepatitis B e antigen (HBeAg) were measured by enzyme-linked immunosorbent assay (ELISA). Secreted HBV DNA and intracellular covalently closed circular DNA (cccDNA) were measured by SYBR green real-time PCR. The 3D crystal structure of HMGB1 (1AAB) protein was developed and docked with the chrysin and lamivudine. In silico drug-likeness, Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) properties of finest ligands were performed by using SwissADME and admetSAR web servers.

RESULTS

Data showed that chrysin significantly decreases HBeAg, HBsAg secretion, supernatant HBV DNA and cccDNA, in a dose dependent manner. The docking studies demonstrated HMGB1 as an important target for chrysin as compared to lamivudine. Chrysin revealed high binding affinity and formed a firm kissing complex with HMGB1 (∆G = - 5.7 kcal/mol), as compared to lamivudine (∆G = - 4.3 kcal/mol), which might be responsible for its antiviral activity.

CONCLUSIONS

The outcome of our study establishes chrysin as a new antiviral against HBV infection. However, using chrysin to treat chronic HBV disease needs further endorsement and optimization by in vivo studies in animal models.

Study of DACH1 Expression and its Epigenetic Regulators as Possible Breast Cancer-Related Biomarkers

Background: Breast carcinogenesis involves both genetic and epigenetic changes. DNA methylation, as well as micro-RNA regulations, are the significant epigenetic phenomena dysregulated in breast cancer. Herein, the expression of DACH1 as a tumor suppressor gene and its promoter methylation status was analyzed in breast cancer tumors. Also, the expression of three micro RNAs (miR-217, miR-6807-3p, and miR-552), which had been previously reported to target DACH1, was assessed.  Methods: The SYBR green-based Real-Time reverse transcription-PCR was used to determine DACH1 and micro-RNAs (miR-217, miR-6807-3p, and miR-552) expression in 120 ductal breast cancer tumors compared with standard control. Also, the promoter methylation pattern of DACH1 was investigated using the Methylation-specific PCR technique. Results: DACH1 expression was significantly down-regulated in breast tumors (p< 0.05). About 33.5% of tumors showed DACH1 promoter hyper-methylation. The studied micro-RNAs, expression was negatively correlated with DACH1 expression. The highest expressions of miRNAs and higher DACH1 promoter methylation were observed in advanced cancer situations. The Kaplan-Meier survival curves indicated that the overall survival was significantly poor in higher miRNAs and lower DACH1 expression in breast cancer patients (p<0.002). Conclusion: DACH1 down-regulation may be associated with a poor breast cancer prognosis. The DACH1 down-regulation may be due to epigenetic regulations such as promoter methylation, especially in triple-negative cases. Other factors, such as micro-RNAs (miR-217, miR-6807-3p, and miR-552), may also have an impact. The elevated expression of miR-217, miR-6807-3p, and miR-552, maybe candidates as possible poor prognostic biomarkers in breast cancer management for further consideration.   

Identification of Natural Products as SENP2 Inhibitors for Targeted Therapy in Heart Failure

Aims: Sentrin-specific protease -2 (SENP2) is involved in deSUMOylation. Increased deSUMOylation in murine hearts by SENP2 upregulation resulted in cardiac dysfunction and congenital heart defects. Natural compounds via regulating cell proliferation and survival, induce cell cycle cessation, cell death, apoptosis, and producing reactive oxygen species and various enzyme systems cause disease prevention. Then, natural compounds can be suitable inhibitors and since SENP2 is a protein involved in heart disease, so our aim was inhibition of SENP2 by natural products for heart disease treatment. Material and methods: Molecular docking and molecular dynamics simulation of natural products i.e. Gallic acid (GA), Caffeic acid (CA), Thymoquinone (TQ), Betanin, Betanidin, Fisetin, and Ebselen were done to evaluate the SENP2 inhibitory effect of these natural products. The toxicity of compounds was also predicted. Results: The results showed that Betanin constituted a stable complex with SENP2 active site as it revealed low RMSD, high binding energy, and hydrogen bonds. Further, as compared to Ebselen, Betanin demonstrated low toxicity, formed a stable complex with SENP2 via four to seven hydrogen bonds, and constituted more stable MD plots. Therefore, depending upon the outcomes presented herein, Betanin significantly inhibited SENP2 and hence may be considered as a suitable natural compound for the treatment of heart failure. Further clinical trials must be conducted to validate its use as a potential SENP2 inhibitor.

Analyzing large scale gene expression data in colorectal cancer reveals important clues; CLCA1 and SELENBP1 downregulated in CRC not in normal and not in adenoma

Early detection of colorectal cancer (CRC) increases the chances of survival and reduces the therapeutic problems and costs of treatment. Since molecular biomarkers can help us diagnose colorectal cancer early, we need to identify novel gene for predicting the early stages of tumorigenesis. Here, we integrated five independent CRC gene expression datasets derived from expression profiling by array comparing CRC with normal samples in: GSE21510, GSE4107, GSE25071, GSE15781 dataset, and GSE8671 dataset, including 64 samples from 32 patients comparing 32 colonic normal mucosa with 32 colorectal adenoma. To detect genes that expressed differentially in experimental circumstances of these datasets, we used web tool of GEO2R to compare groups of samples in the GEO data series. Furthermore, we constructed the protein-protein interactions network by STRING database for mostly downregulated genes and the expression of their members in PPI network were studied into five datasets separately. Also, the level of expression of selected biomarker genes in different stages of CRC compared to normal was studied. Our data revealed 17 common downregulated genes (average fold change (FC) in five tests ≥6) in CRC in comparison with normal (Test 1 to Test 4) and in adenoma compared with normal (Test 5). Studying of gene expression of PPI network members of these downregulated genes led to identifying of CLCA1, SELENBP1, CWC25, ACOT11, GUCY2C and ALDH1A1 as suppressor genes and PTGS2, PROCR, MOCS3 and NFS1 as oncogenes which respectively downregulated and upregulated in CRC. Since decreasing of gene expression was seen in CRC comparing with normal and due to no different expression seen for these 10 genes in adenoma, they, especially CLCA1 and SELENBP1, could be considered as biomarkers for early detection of CRC. Before using these signature genes in the clinic; however, further validations are required.

Computational drug repurposing of bethanidine for SENP1 inhibition in cardiovascular diseases treatment

AIMS

Bethanidine (BW467C60) is a newly presented strong adrenergic neuron blocking factor which has a hypotensive operation in man. SENPs are essential for maintaining a balance between SUMOylation and deSUMOylation which can be disturbed by changing the expression of (sentrin-specific proteases) SENPs. SENP1 is the most studied isoform of SENPs. Hypertrophic stimuli can increase SENP1 expression using calcium/calcineurin-NFAT3 signaling in heart. Moreover, SENP1 expression may positively relate to the expression of mitochondrial genes of the heart, and can cause the heart and mitochondrial dysfunction.

MATERIALS AND METHODS

In order to inhibit SENP1 using Bethanidine, molecular docking and molecular dynamics (MD) simulation of SENP1 with Bethanidine were performed. Molecular docking showed that Bethanidine can inhibit SENP1.

KEY FINDINGS

MD Simulation showed that Bethanidine constitutes a stable complex with SENP1 as was evident from RMSD, RMSF, H-bond and DSSP plots. Free binding energy and the interaction patterns were obtained from molecular docking, and MD trajectory exhibited Bethanidine can be a potential drug candidate for SENP1 inhibition.

SIGNIFICANCE

This study supplies enough evidences that Bethanidine is a potential inhibitor of SENP1 and can be applied for the treatment of cardiovascular diseases.

An investigation on the c-MYC, AXIN1, and COL11A1 gene expression in colorectal cancer

The high incidence rate of CRC demands early diagnosis of the disease and readiness of diagnostic biomarker. In present study, we have investigated c-MYC, AXIN1, and COL11A1 expression levels in course of CRC progression and their correlation with demographics and clinical risk factors. Fifty-five tumors and 41 normal tissues were obtained from Tumor Bank of Iran, total RNA was extracted, cDNA was synthesized, and RT-qPCR was performed. Results were analyzed using Rest 2009 and SPSS software. Analysis at mRNA level showed upregulation of the two genes; c-MYC with a p-value of 0.001 and COL11A1 with an observed p-value of 0.02, while a p-value of 0.04 indicated AXIN1 downregulation. The observed overexpression of COL11A1 in stage 0 compared to other stages of CRC asserts importance of this gene in CRC prognosis. Moreover, statistical analysis confirms a significant correlation between expression of these genes and several clinical risk factors of CRC. Our study supports the importance of the studied genes and provides further information regarding the molecular mechanism of CRC. Further studies on these genes could elucidate their pivotal role for both early detection and/or diagnosis of CRC in addition to have important biomarkers for CRC management available.

Evidence of Omics, Immune Infiltration, and Pharmacogenomic for SENP1 in the Pan-Cancer Cohort

Sentrin specific-protease 1 (SENP1) is a protein involved in deSUMOylation that is almost overexpressed in cancer. SENP1 has a determinative role in the activation of transcription programs in the innate immune responses and the development B of and C lymphocytes. We found, SENP1 possibly plays a critical role in immune infiltration and acts as an expression marker in PAAD, ESCA, and THYM. CD4+ T cells, CD8+ T cells, and macrophages were more key-related immune cells, indicating that SENP1 might be introduced as a potential target for cancer immunotherapy. We further showed that dysregulation of SENP1 is powerfully associated with decreased patient survival and clinical stage. Total SENP1 protein also increases in cancer. SENP1 is also controlled by transcription factors (TFs) CREB1, KDM5A, REST, and YY1 that regulates apoptosis, cell cycle, cell proliferation, invasion, tumorigenesis, and metastasis. These TFs were in a positive correlation with SENP1. MiR-138-5p, miR-129-1-3p, and miR-129-2-3p also inhibit tumorigenesis through targeting of SENP1. The SENP1 expression level positively correlated with the expression levels of UBN1, SP3, SAP130, NUP98, NUP153 in 32 tumor types. SENP1 and correlated and binding genes: SAP130, NUP98, and NUP153 activated cell cycle. Consistent with this finding, drug analysis was indicated SENP1 is sensitive to cell cycle, apoptosis, and RTK signaling regulators. In the end, SENP1 and its expression-correlated and functional binding genes were enriched in cell cycle, apoptosis, cellular response to DNA damage stimulus. We found that the cell cycle is the main way for tumorigenesis by SENP1. SENP1 attenuates the effect of inhibitory drugs on the cell cycle. We also introduced effective FDA-Approved drugs that can inhibit SENP1. Therefore in the treatments in which these drugs are used, SENP1 inhibition is a suitable approach. This study supplies a wide analysis of the SENP1 across The Cancer Genome Atlas (CGA) cancer types. These results suggest the potential roles of SENP1 as a biomarker for cancer. Since these drugs and the drugs that cause to resistance are applied to cancer treatment, then these two class drugs can use to inhibition of SENP1.

Rational design of hyper-glycosylated human follicle-stimulating hormone analogs (a bioinformatics approach)

N-glycosylation is a complex mechanism in which the carbohydrate molecules bind to the Asn amino acid in the N-glycan consensus sequence (AsnXxxThr/Ser sequon, where Xxx is any residue, excluding Pro). Introduction of additional N-linked glycosylation site into proposed location in the protein causes to its hyper-glycosylation and can enhance the protein characteristics to provide promising prospects in treatment. Glycoengineering is a favorably used strategy to design and generate hyper-glycosylated variants. In this research, human follicle-stimulating hormone (HuFSH) was considered to identify appropriate positions for adding novel N-glycan sites. A rational computational strategy was applied to predict functional/structural variations induced through changes in polypeptide chain. We analyzed the amino acid chain of FSH to find out the proper locations to introduce asparagine and/or threonine for creating novel N-glycan positions. This analysis resulted in the recognition of 40 possible N-glycosylation positions, and then the eight adequate ones were chosen for additional investigation. The model validation techniques were used to examine 3-dimensional structures of the chosen mutant proteins. Finally, 2 mutants with a further glycan site were recommended as eligible FSH hyper-glycosylated analogs, which may be regarded for subsequent experimental studies. Our in silico approach may decrease tedious and time-wasting laboratory researches of the mutants.Communicated by Ramaswamy H. Sharma.

Identification of novel anti-cancer agents, applying in silico method for SENP1 protease inhibition

The SENP1 (Sentrin-Specific Protease1) is essential for desumoylation. SENP1 plays an essential role in many diseases such as cardiovascular disease, diabetes and cancer via targeting GATA2, NEMO, Pin1, SMAD4 and HIF-1α for deSUMOylation. Considering that, over expression of SENP1 was reported in cancer, thus an optional inhibitor of SENP1 can restitute the balance to the skewed system of SUMO and act as an effective therapeutic agent. The purpose of this study was to select and to sort inhibitors with a stronger binding affinity with SENP1. Molecular docking of SENP1 with natural compounds including Gallic acid, Caffeic acid, Thymoquinone, Thymol, Betaine, Alkannin, Ellagic acid, Betanin, Shikonin, Betanidin and Momordin IC was performed using AutoDock 4, then docking complexes for molecular dynamics (MD) simulation with GROMACS 4.6.5 were applied. Results with RMSD, RMSF, SASA, DSSP, gyrate, H-bond, ADMET and TOPKAT measurements, binding energy and structural features were surveyed. Among those, Gallic acid has shown the most significant results including RMSD and RMSF plots with high stability, high hydrogen bonds, high binding energy and the highest intermolecular bonds with SENP1. Gallic acid demonstrated strong connections and results of toxicity better than Momordin as control. Gallic acid is a phenolic compound which affects several pharmacological and biochemical pathways and has strong antioxidant, anti-inflammatory, antimutagenic and anticancer properties. Further research can improve the appropriate use of plant products drastically. Basic, pre-clinical and clinical research on Gallic acid may provide a roadmap for its ultimate application in the field of cancer prevention.Communicated by Ramaswamy H. Sarma.

Rational Design of Hyper-glycosylated Human Chorionic Gonadotropin Analogs (A Bioinformatics Approach)

Background:

Protein pharmaceuticals routinely display a series of intrinsic physicochemical instabilities during their production and administration that can unfavorably affect their therapeutic effectiveness. Glycoengineering is one of the most desirable techniques to improve the attributes of therapeutic proteins. One aspect of glycoengineering is the rational manipulation of the peptide backbone to introduce new N-glycosylation consensus sequences (Asn-X-Ser/Thr, where X is any amino acid except proline).

Methods:

In this work, the amino acid sequence of human chorionic gonadotropin (hCG) was analyzed to identify suitable positions in order to create new N-glycosylation sites. This survey led to the detection of 46 potential N-glycosylation sites. The N-glycosylation probability of all the potential positions was measured with the NetNGlyc 1.0 server. After theoretical reviews and the removal of unsuitable positions, the five acceptable ones were selected for more analyses. Then, threedimensional (3D) structures of the selected analogs were generated and evaluated by SPDBV software. The molecular stability and flexibility profile of five designed analogs were examined using Molecular Dynamics (MD) simulations.

Results:

Finally, three analogs with one additional N-glycosylation site (V68T, V79N and R67N) were proposed as the qualified analogs that could be glycosylated at the new sites.

Conclusion:

According to the results of this study, further experimental investigations could be guided on the three analogs. Therefore, our computational strategy can be a valuable method due to the reduction in the number of the expensive, tiresome and time-consuming experimental studies of hCG analogs.

Betanin purification from red beetroots and evaluation of its anti-oxidant and anti-inflammatory activity on LPS-activated microglial cells

Microglial activation can release free radicals and various pro-inflammatory cytokines, which implicates the progress of a neurodegenerative disease. Therefore suppression of microglial activation can be an appropriate strategy for combating neurodegenerative diseases. Betanin is a red food dye that acts as free radical scavenger and can be a promising candidate for this purpose. In this study, purification of betanin from red beetroots was carried out by normal phase colum chromatography, yielding 500 mg of betanin from 100 g of red beetroot. The purified betanin was evaluated by TLC, UV-visible, HPLC, ESI-MASS, FT-IR spectroscopy. Investigation on the inhibitory effect of betanin on activated microglia was performed using primary microglial culture. The results showed that betanin significantly inhibited lipopolysaccharide induced microglial function including the production of nitric oxide free radicals, reactive oxygen species, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-1 beta (IL-1β). Moreover, betanin modulated mitochondrial membrane potential, lysosomal membrane permeabilization and adenosine triphosphate. We further investigated the interaction of betanin with TNF-α, IL-6 and Nitric oxide synthase (iNOS or NOS2) using in silico molecular docking analysis. The docking results demonstrated that betanin have significant negative binding energy against active sites of TNF-α, IL-6 and iNOS.

Immunopeptidome screening to design An immunogenic construct against PRAME positive breast cancer; An in silico study

BACKGROUND

Metastasis is the main cause of breast cancer (BC) lethality, especially in early stages, led to improvements in therapeutic procedures. Lately, by improvements in our perception of biological processes and immune system new classes of vaccines are emerged that grant us the opportunity of designing resolute constructs against desired antigens. In the current study, we used a variety of immunoinformatics tools to design a novel cancer vaccine against Preferentially Expressed Antigen of Melanoma (PRAME), which counts as a cancer testis antigen for various human cancers including BC. The PRAME up-regulation leads to strengthen BC stem cells maintenance, drug resistance, cell survival, adaptation, and apoptosis evading in cancerous cells.

METHODS AND RESULTS

The PRAME co-expressed genes were mined and validated through BC RNA-sequencing of TCGA data. The immunodominant T-cell predicted epitopes were fused and engineered to form the vaccine. The safety, allergenicity, and immunogenic capabilities of the vaccine were confirmed by promising immunoinformatics tools. The vaccine's structure was verified to be hydrophilic in most areas through Kyte and Doolittle hydrophobicity plotting. The interactions between the designed vaccine and immune receptors of TLR4 and IL1R were confirmed by protein-protein docking after modeling its tertiary structure. Finally, codon optimization and in silico cloning were performed to guarantee better in-vivo results.

CONCLUSION

In conclusion, concerning in silico assessments' results in this study, the designed vaccine can potentially boost immune responses against PRAME, therefore may decrease BC development and metastasis. According to the mined PRAME co-expressed genes and their functional annotation, cell cycle regulation is the prime mechanism opted by this construct and its adjacent regulatory genes along boosting immune reactions.

Rational design of hyper-glycosylated human luteinizing hormone analogs (a bioinformatics approach)

Glycoengineering is a recently used approach to extend serum half-life of valuable protein therapeutics. One aspect of glycoengineering is to introduce new N-glycosylation site (Asn-X-Thr/Ser, where X ≠ Pro) into desirable positions in the peptide backbone, resulting in the generation of hyper-glycosylated protein. In this study, human luteinizing hormone (LH) was considered for identification of the suitable positions for the addition of new N-linked glycosylation sites. A rational in silico approach was applied for prediction of structural and functional alterations caused by changes in amino acid sequence. As the first step, we explored the amino acid sequence of LH to find out desirable positions for introducing Asn or/and Thr to create new N-glycosylation sites. This exploration led to the identification of 38 potential N-glycan sites, and then the four acceptable ones were selected for further analysis. Three-dimensional (3D) structures of the selected analogs were generated and examined by the model evaluation methods. Finally, two analogs with one additional glycosylation site were suggested as the qualified analogs for hyper-glycosylation of the LH, which can be considered for further experimental investigations. Our computational strategy can reduce laborious and time-consuming experimental analyses of the analogs.

Analysis of microRNA and Gene Expression Profiles in Alzheimer's Disease: A Meta-Analysis Approach

Understanding the molecular mechanisms underlying Alzheimer’s disease (AD) is necessary for the diagnosis and treatment of this neurodegenerative disorder. It is therefore important to detect the most important genes and miRNAs, which are associated with molecular events, and studying their interactions for recognition of AD mechanisms. Here we focus on the genes and miRNAs expression profile, which we have detected the miRNA target genes involved in AD. These are the most quintessential to find the most important miRNA, to target genes and their important pathways. A total of 179 differentially expressed miRNAs (DEmiRs) and 1404 differentially expressed genes (DEGs) were obtained from a comprehensive meta-analysis. Also, regions specific genes with their molecular function in AD have been demonstrated. We then focused on miRNAs which regulated most genes in AD, alongside we analyzed their pathways. The miRNA-30a-5p and miRNA-335 elicited a major function in AD after analyzing the regulatory network, we showed they were the most regulatory miRNAs in the AD. In conclusion, we demonstrated the most important genes, miRNAs, miRNA-mRNA interactions and their related pathways in AD using Bioinformatics methods. Accordingly, our defined genes and miRNAs could be used for future molecular studies in the context of AD.

Gastric cancer biomarkers; A systems biology approach

Gastric cancer is one of the most fatal cancers in the world. Many efforts in recent years have attempted to find effective proteins in gastric cancer. By using a comprehensive list of proteins involved in gastric cancer, scientists were able to retrieve interaction information. The study of protein-protein interaction networks through systems biology based analysis provides appropriate strategies to discover candidate proteins and key biological pathways.

In this study, we investigated dominant functional themes and centrality parameters including betweenness as well as the degree of each topological clusters and expressionally active sub-networks in the resulted network. The results of functional analysis on gene sets showed that neurotrophin signaling pathway, cell cycle and nucleotide excision possess the strongest enrichment signals. According to the computed centrality parameters, HNF4A, TAF1 and TP53 manifested as the most significant nodes in the interaction network of the engaged proteins in gastric cancer. This study also demonstrates pathways and proteins that are applicable as diagnostic markers and therapeutic targets for future attempts to overcome gastric cancer.

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A systematic study of protein-protein interaction networks through comprehensive extracted list of proteins involved in gastric cancer.

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Dominant functional theme and pathways of each topological clusters and expressionally active subnetworks were reported.

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The most effective proteins in gastric cancer formation were proposed according to the computed centrality parameters.

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HNF4A, TAF1and TP53 were mentioned as the key proteins in gastric cancer.

Exploring the cross talk between ER stress and inflammation in age-related macular degeneration

Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.

Chameleon sequences in neurodegenerative diseases

Chameleon sequences can adopt either alpha helix sheet or a coil conformation. Defining chameleon sequences in PDB (Protein Data Bank) may yield to an insight on defining peptides and proteins responsible in neurodegeneration. In this research, we benefitted from the large PDB and performed a sequence analysis on Chameleons, where we developed an algorithm to extract peptide segments with identical sequences, but different structures. In order to find new chameleon sequences, we extracted a set of 8315 non-redundant protein sequences from the PDB with an identity less than 25%. Our data was classified to "helix to strand (HE)", "helix to coil (HC)" and "strand to coil (CE)" alterations. We also analyzed the occurrence of singlet and doublet amino acids and the solvent accessibility in the chameleon sequences; we then sorted out the proteins with the most number of chameleon sequences and named them Chameleon Flexible Proteins (CFPs) in our dataset. Our data revealed that Gly, Val, Ile, Tyr and Phe, are the major amino acids in Chameleons. We also found that there are proteins such as Insulin Degrading Enzyme IDE and GTP-binding nuclear protein Ran (RAN) with the most number of chameleons (640 and 405 respectively). These proteins have known roles in neurodegenerative diseases. Therefore it can be inferred that other CFP's can serve as key proteins in neurodegeneration, and a study on them can shed light on curing and preventing neurodegenerative diseases.

An Ontology-Based GIS for Genomic Data Management of Rumen Microbes

During recent years, there has been exponential growth in biological information. With the emergence of large datasets in biology, life scientists are encountering bottlenecks in handling the biological data. This study presents an integrated geographic information system (GIS)-ontology application for handling microbial genome data. The application uses a linear referencing technique as one of the GIS functionalities to represent genes as linear events on the genome layer, where users can define/change the attributes of genes in an event table and interactively see the gene events on a genome layer. Our application adopted ontology to portray and store genomic data in a semantic framework, which facilitates data-sharing among biology domains, applications, and experts. The application was developed in two steps. In the first step, the genome annotated data were prepared and stored in a MySQL database. The second step involved the connection of the database to both ArcGIS and Protégé as the GIS engine and ontology platform, respectively. We have designed this application specifically to manage the genome-annotated data of rumen microbial populations. Such a GIS-ontology application offers powerful capabilities for visualizing, managing, reusing, sharing, and querying genome-related data.

The Increased Level of Serum p53 in Hepatitis B-Associated Liver Cirrhosis

BACKGROUND

The ability of tumour suppressor protein p53 (P53) to regulate cell cycle processes can be modulated by hepatitis B virus (HBV). While preliminary evidences indicates the involvement of protein-x of HBV (HBx) in altering p53 DNA binding, no further data have been accumulated for the significance of serum p53 in chronic hepatitis B virus infected patients.

METHODS

72 non-cirrhotic and 19 cirrhotic patients infected by HBV were enrolled for the analysis in this study. Enzyme linked immunosorbent assay (ELISA) was performed to study the concentrations of serum p53 protein. The tertiary structures of HBx and P53 were docked by Z-dock and Hex servers for in-silico protein-protein interaction analysis.

RESULTS

There was a significant association between the serum p53 and cirrhosis (OR=1.81 95% CI: 1.017-3.2, P=0.044). Cirrhotic patients had higher level of serum p53 compare with chronic infection of HBV (1.98±1.22 vs. 1.29±0.72 U/ml, P=0.05). No evidence of correlation was seen between the different variables such as age, gender, log viral load, serum alkaline phosphatase (ALP) and alanine aminotransferase (ALT) with serum p53. Tertiary model shows that the amino acid residues from Arg110 to Lys132 of the N-terminal of P53 which is critical for ubiquitination, are bonded to a region in N- terminal of HBx amino acid residues from Arg19 to Ser33.

CONCLUSION

There is an increase in serum p53 in HBV-related cirrhosis patients. In this case, HBx might be responsible for such higher concentration of p53 through HBx-p53 protein-protein interaction, as is shown by molecular modeling approach.

Molecular dynamic study of human prion protein upon D178N mutation: new perspective to H-bonds, salt bridges and the critical amino acids

The molecular dynamics simulation method was used to investigate the structural details for human prion protein (PrPN) and its D178N mutant (PrPM). Root-mean-square fluctuations (RMSFs) and the root-mean-square deviations (RMSDs) showed an increase in the flexibility and high dynamic plasticity of PrPM. Average Total energy for PrPM and PrPN sequentially was -2.975 x105 (kJmol-1) and -3.193 x 105 (kJmol-1). The results showed conformational rearrangement susceptibility for PrPM. For PrPM, highly surface-exposed Glu196 and Arg136 caused hydrogen bond weakening and electrostatic interactions changes in salt bridges. Hydrogen bond weakening under mutation can be mentioned as the leader of conformational changes and disease-related conversions. Contrary to some reports, the contributions of electrostatic interactions of Glu146-Arg208 and Arg156-Glu196 salt bridges for PrPN is less than of these interactions for PrPM. These interactions can pave the way to conformational changes in PrPM. The results showed that the role of the hydrogen bonds in the stability of human prion protein is more important than these salt bridges. The calculation of the solvent accessible surface area showed that the conformational plasticity in PrPM is mainly due to Asn residues that were solvent exposed. Conformational changes in the specific amino acids can affect metal-ion occupancy and function. The secondary structure has also showed that the structural transition arose from D178N mutation and occurs in specific residues. Our studies support the large scale effects of electrostatic forces at key position 178 of prion. As a result, the conformational rearrangements happen by eliminating only a single negative charge because of the mutation induced global forces in the prion structure. These rearrangements can be considered as a molecular switch, which triggers the initial stages of the conformational transition.

Expression Enhancement in Trastuzumab Therapeutic Monoclonal Antibody Production using Genomic Amplification with Methotrexate

BACKGROUND

Trastuzumab (Herceptin) is a humanized monoclonal antibody (mAb) which is used for specific treatment of metastatic breast cancer in patients with overexpression of HER2/neu receptor. In this study, we have attempted to develop a biosimilar version of trastuzumab mAb.

METHODS

According to in silico studies, the heavy and light chains of trastuzumab mAb were designed and constructed. The recombinant constructs were co-transfected in CHO DG44 cell line. Stable transformants were selected on a semi solid medium. Genomic amplification with methotrexate was achieved for heavy chain gene amplification. Biological activity of produced antibody in comparison with Herceptin was tested by flow cytometry method.

RESULTS

Three folds of amplification were obtained after seven rounds of methotrexate treatments. The results indicated the equal expression level of heavy and light chains. The yield of purified mAb was between 50 to 60 mg/l /day. According to the results, the produced mAb had similar affinity to HER2(+) tumor cells to that of Herceptin.

CONCLUSION

High-level recombinant protein expression can be achieved by amplification of the recombinant gene with a selectable marker, such as Dihydrofolate Reductase (DHFR). It is usually accepted that DHFR gene can be amplified in DHFR(－) CHO cells, which consequently leads to amplification of the co-linked target gene, and finally amplification of recombinant protein. In this research, with the aim of producing a biosimilar version of herceptin, the effect of genomic amplification was investigated on the increasing the gene copy number using quantitative real-time PCR.

In silico design, construction and cloning of Trastuzumab humanized monoclonal antibody: A possible biosimilar for Herceptin

Background:

There is a novel hypothesis in that antibodies may have specificity for two distinct antigens that have been named “dual specificity”. This hypothesis was evaluated for some defined therapeutic monoclonal antibodies (mAbs) such as Trastuzumab, Pertuzumab, Bevacizumab, and Cetuximab. In silico design and construction of expression vectors for trastuzumab monoclonal antibody also in this work were performed.

Materials and Methods:

First, in bioinformatics studies the 3D structures of concerned mAbs were obtained from the Protein Data Bank (PDB). Three-dimensional structural alignments were performed with SIM and MUSTANG softwares. AutoDock4.2 software also was used for the docking analysis. Second, the suitable genes for trastuzumab heavy and light chains were designed, synthesized, and cloned in the prokaryotic vector. These fragments individually were PCR amplified and cloned into pcDNA™ 3.3-TOPO^® and pOptiVEC™ TOPO^® shuttle vectors, using standard methods.

Results:

First, many bioinformatics tools and softwares were applied but we did not meet any new dual specificity in the selected antibodies. In the following step, the suitable expression cascade for the heavy and light chains of Trastuzumab therapeutic mAb were designed and constructed. Gene cloning was successfully performed and created constructs were confirmed using gene mapping and sequencing.

Conclusions:

This study was based on a recently developed technology for mAb expression in mammalian cells. The obtained constructs could be successfully used for biosimilar recombinant mAb production in CHO DG44 dihydrofolate reductase (DHFR) gene deficient cell line in the suspension culture medium.

Protein-x of hepatitis B virus in interaction with CCAAT/enhancer-binding protein α (C/EBPα)--an in silico analysis approach

Background

Even though many functions of protein-x from the Hepatitis B virus (HBV) have been revealed, the nature of protein-x is yet unknown. This protein is well-known for its transactivation activity through interaction with several cellular transcription factors, it is also known as an oncogene. In this work, we have presented computational approaches to design a model to show the structure of protein-x and its respective binding sites associated with the CCAAT/enhancer-binding protein α (C/EBPα). C/EBPα belongs to the bZip family of transcription factors, which activates transcription of several genes through its binding sites in liver and fat cells. The C/EBPα has been shown to bind and modulate enhancer I and the enhancer II/core promoter of HBV. In this study using the bioinformatics tools we tried to present a reliable model for the protein-x interaction with C/EBPα.

Results

The amino acid sequence of protein-x was extracted from UniProt [UniProt:Q80IU5] and the x-ray crystal structure of the partial CCAAT-enhancer α [PDB:1NWQ] was retrieved from the Protein Data Bank (PDB). Similarity search for protein-x was carried out by psi-blast and bl2seq using NCBI [GenBank: BAC65106.1] and Local Meta-Threading-Server (LOMETS) was used as a threading server for determining the maximum tertiary structure similarities. Advanced MODELLER was implemented to design a comparative model, however, due to the lack of a suitable template, Quark was used for ab initio tertiary structure prediction.

The PDB-blast search indicated a maximum of 23% sequence identity and 33% similarity with crystal structure of the porcine reproductive and respiratory syndrome virus leader protease Nsp1α [PDB:3IFU]. This meant that protein-x does not have a suitable template to predict its tertiary structure using comparative modeling tools, therefore we used QUARK as an ab initio 3D prediction approach. Docking results from the ab initio tertiary structure of protein-x and crystal structure of the C/EBPα- DNA region [PDB:1NWQ] illustrated the protein-binding site interactions. Indeed, the N-terminal part of 1NWQ has a high affinity for certain regions in protein-x (e.g. from Ala76 to Ser101 and Thr105 to Glu125).

Conclusion

In this study, we predicted the structure of protein-x of HBV in interaction with C/EBPα. The docking results showed that protein-x has an interaction synergy with C/EBPα. However, despite previous experimental data, protein-x was found to interact with DNA. This can lead to a better understanding of the function of protein-x and may provide an opportunity to use it as a therapeutic target.

Propensity of amino acids in loop regions connecting beta-strands

The fact that loops assume important roles in molecular functions and biological recognition is well known. In this study the Propensity and the Relative entropy of amino-acids in loop structures connecting beta-strands are calculated. Results showed that Asn is the most frequently occurring amino-acid in loop regions connecting beta-strands, followed by Gly, Asp, Ser, and Thr. Results presented here can serve for modeling loop structures connecting beta-strands in proteins.

Exceptional pairs of amino acid neighbors in alpha-helices

Amino acids seem to have specific preferences for various locations in alpha-helices. These specific preferences, called singlet local propensity (SLP), have been determined by calculating the preference of occurrence of each amino acid in different positions of the alpha-helix. We have studied the occurrence of amino acids, single or pairs, in different positions, singlet or doublet, of alpha-helices in a database of 343 non-homologous proteins representing a unique superfamily from the SCOP database with a resolution better than 2.5 A from the Protein Data Bank. The preference of single amino acids for various locations of the helix was shown by the relative entropy of each amino acid with respect to the background. Based on the total relative entropy of all amino acids occurring in a single position, the N(cap) position was found to be the most selective position in the alpha-helix. A rigorous statistical analysis of amino acid pair occurrences showed that there are exceptional pairs for which, the observed frequency of occurrence in various doublet positions of the alpha-helix is significantly different from the expected frequency of occurrence in that position. The doublet local propensity (DLP) was defined as the preference of occurrences of amino acid pairs in different doublet positions of the alpha-helix. For most amino acid pairs, the observed DLP (DLP(O)) was nearly equal to the expected DLP (DLP(E)), which is the product of the related SLPs. However, for exceptional pairs of amino acids identified above, the DLP(O) and DLP(E) values were significantly different. Based on the relative values of DLP(O) and DLP(E), exceptional amino acid pairs were divided into two categories. Those, for which the DLP(O) values are higher than DLP(E), should have a strong tendency to pair together in the specified position. For those pairs which the DLP(O) values are less than DLP(E), there exists a hindrance in neighboring of the two amino acids in that specific position of the alpha-helix. These cases have been identified and listed in various tables in this paper. The amount of mutual information carried by the exceptional pairs of amino acids was significantly higher than the average mutual information carried by other amino acid pairs. The average mutual information conveyed by amino acid pairs in each doublet position was found to be very small but non-zero.

Inhibition and recovery of GM-CSF production in the lung after hyperthermia

The purpose of this work was to study the response that is invoked by hyperthermia in the production of Granulocyte-Macrophage colony-stimulating factor (GM-CSF) by the lung. Rats were heated regionally at chest area by a RF generator operating at 27.397 MHz for 1 h at various temperatures and then allowed to recover or repair in various periods of time after heat application. Lung tissue from these animals was then removed and cultured for the production of GM-CSF. GM-CSF was assayed by the production of colonies in the semi-solid agar cultures of bone marrow cells. Immediately after heat treatment hyperthermia had no significant effect on the production of GM-CSF by the lung. A delayed effect was observed about 3.5 h after heat treatment. This effect consisted of a temperature dependent decrease in GM-CSF production. The damage was recoverable and required 1-50 days of post heat treatment time for animals to reach normal level of GM-CSF production. The results suggest that in-vivo application of hyperthermia invokes temporary reduction in GM-CSF production by the lung, which has not been reported previously.