Ribavirin inhibits the replication of infectious bursal disease virus predominantly through depletion of cellular guanosine pool.

Introduction: The antiviral activity of different mutagens against single-stranded RNA viruses is well documented; however, their activity on the replication of double-stranded RNA viruses remains unexplored. This study aims to investigate the effect of different antivirals on the replication of a chicken embryo fibroblast-adapted Infectious Bursal Disease virus, FVSKG2. This study further explores the antiviral mechanism utilized by the most effective anti-IBDV agent. Methods: The cytotoxicity and anti-FVSKG2 activity of different antiviral agents (ribavirin, 5-fluorouracil, 5-azacytidine, and amiloride) were evaluated. The virus was serially passaged in chicken embryo fibroblasts 11 times at sub-cytotoxic concentrations of ribavirin, 5-fluorouracil or amiloride. Further, the possible mutagenic and non-mutagenic mechanisms utilized by the most effective anti-FVSKG2 agent were explored. Results and Discussion: Ribavirin was the least cytotoxic on chicken embryo fibroblasts, followed by 5-fluorouracil, amiloride and 5-azacytidine. Ribavirin inhibited the replication of FVSKG2 in chicken embryo fibroblasts significantly at concentrations as low as 0.05 mM. The extinction of FVSKG2 was achieved during serial passage of the virus in chicken embryo fibroblasts at ≥0.05 mM ribavirin; however, the emergence of a mutagen-resistant virus was not observed until the eleventh passage. Further, no mutation was observed in 1,898 nucleotides of the FVSKG2 following its five passages in chicken embryo fibroblasts in the presence of 0.025 mM ribavirin. Ribavarin inhibited the FVSKG2 replication in chicken embryo fibroblasts primarily through IMPDH-mediated depletion of the Guanosine Triphosphate pool of cells. However, other mechanisms like ribavirin-mediated cytokine induction or possible inhibition of viral RNA-dependent RNA polymerase through its interaction with the enzyme's active sites enhance the anti-IBDV effect. Ribavirin inhibits ds- RNA viruses, likely through IMPDH inhibition and not mutagenesis. The inhibitory effect may, however, be augmented by other non-mutagenic mechanisms, like induction of antiviral cytokines in chicken embryo fibroblasts or interaction of ribavirin with the active sites of RNA-dependent RNA polymerase of the virus.

An Investigation of the Antiviral Potential of Phytocompounds against Avian Infectious Bronchitis Virus through Template-Based Molecular Docking and Molecular Dynamics Simulation Analysis.

Vaccination is widely used to control Infectious Bronchitis in poultry; however, the limited cross-protection and safety issues associated with these vaccines can lead to vaccination failures. Keeping these limitations in mind, the current study explored the antiviral potential of phytocompounds against the Infectious Bronchitis virus using in silico approaches. A total of 1300 phytocompounds derived from fourteen botanicals were screened for their potential ability to inhibit the main protease, papain-like protease or RNA-dependent RNA-polymerase of the virus. The study identified Methyl Rosmarinate, Cianidanol, Royleanone, and 6,7-Dehydroroyleanone as dual-target inhibitors against any two of the key proteins. At the same time, 7-alpha-Acetoxyroyleanone from Rosmarinus officinalis was found to be a multi-target protein inhibitor against all three proteins. The potential multi-target inhibitor was subjected to molecular dynamics simulations to assess the stability of the protein-ligand complexes along with the corresponding reference ligands. The findings specified stable interactions of 7-alpha-Acetoxyroyleanone with the protein targets. The results based on the in silico study indicate that the phytocompounds can potentially inhibit the essential proteins of the Infectious Bronchitis virus; however, in vitro and in vivo studies are required for validation. Nevertheless, this study is a significant step in exploring the use of botanicals in feed to control Infectious Bronchitis infections in poultry.

A multiepitope vaccine candidate against infectious bursal disease virus using immunoinformatics-based reverse vaccinology approach.

Infectious bursal disease virus is the causative agent of infectious bursal disease (Gumboro disease), a highly contagious immunosuppressive disease of chicken with a substantial economic impact on small- and large-scale poultry industries worldwide. Currently, live attenuated vaccines are widely used to control the disease in chickens despite their issues with safety (immunosuppression and bursal atrophy) and efficiency (breaking through the maternally-derived antibody titer). To overcome the drawbacks, the current study has, for the first time, attempted to construct a computational model of a multiepitope based vaccine candidate against infectious bursal disease virus, which has the potential to overcome the safety and protection issues found in the existing live-attenuated vaccines. The current study used a reverse vaccinology based immunoinformatics approach to construct the vaccine candidate using major and minor capsid proteins of the virus, VP2 and VP3, respectively. The vaccine construct was composed of four CD8+ epitopes, seven CD4+ T-cell epitopes, 11 B-cell epitopes and a Cholera Toxin B adjuvant, connected using appropriate flexible peptide linkers. The vaccine construct was evaluated as antigenic with VaxiJen Score of 0.6781, immunogenic with IEDB score of 2.89887 and non-allergenic. The 55.64 kDa construct was further evaluated for its physicochemical characteristics, which revealed that it was stable with an instability index of 16.24, basic with theoretical pI of 9.24, thermostable with aliphatic index of 86.72 and hydrophilic with GRAVY score of -0.256. The docking and molecular dynamics simulation studies of the vaccine construct with Toll-like receptor-3 revealed fair structural interaction (binding affinity of -295.94 kcal/mol) and complex stability. Further, the predicted induction of antibodies and cytokines by the vaccine construct indicated the possible elicitation of the host's immune response against the virus. The work is a significant attempt to develop next-generation vaccines against the infectious bursal disease virus though further experimental studies are required to assess the efficacy and protectivity of the proposed vaccine candidate in vivo.

Indolylkojyl methane analogue IKM5 potentially inhibits invasion of breast cancer cells via attenuation of GRP78.

PURPOSE: More than 90% of the breast cancer deaths occur due to the metastasis of the cancer cells to secondary organ sites. Increased Glucose-regulated protein 78 (GRP78) expression is critical for epithelial-mesenchymal transition (EMT) and invasion in breast cancer resulting in poor patient survival outcomes. Therefore, there is an urgent need of potential inhibitors of GRP78 for the abrogation of invasion and metastasis in breast cancer. METHODS: We investigated the effect of IKM5 (2-(1-(1H-indol-3-yl)octyl)-3-hydroxy-6-(hydroxymethyl)-4H-pyran-4-one) (a novel Indolylkojyl methane analogue) on invasion abilities of human breast cancer cells employing invadopodia formation, Matrigel invasion assays, and mouse models for metastasis. The mechanism underlying the anti-invasive effect of IKM5 was examined through molecular docking, immunoblotting, immunocytochemistry, co-immunoprecipitation analysis, siRNA silencing, and sub-cellular fractionation studies. RESULTS: Treatment with IKM5 at its sub-toxic concentration (200 nM) suppressed invasion and invadopodia formation, and growth factor-induced cell scattering of aggressive human breast cancer MDA-MB-231, MDA-MB-468, and MCF7 cells. IKM5 spontaneously binds to GRP78 (Ki = 1.35 µM) and downregulates its expression along with the EMT markers MMP-2, Twist1, and Vimentin. Furthermore, IKM5 amplified the expression and nuclear translocation of tumor suppressor Par-4 to control NF-kB-mediated pro-EMT activities. Interestingly, IKM5 disrupts the interaction between GRP78 and TIMP-1 by inhibiting GRP78 in a Par-4-dependent manner. Moreover, IKM5 inhibited tumor growth and lung metastasis at a safe dose of 30 mg/kg/body weight. CONCLUSION: Our study warrants IKM5, a potential anticancer agent that can abrogate invasion and metastasis, suggesting its clinical development for the treatment of patients with advanced breast cancer.

D224V and S128Y mutation in FSHRED influence thumb movement differentially: An intricate insight gained by short-term molecular dynamics simulation.

Follicle-stimulating hormone-follicle-stimulating hormone receptor (FSH-FSHR) interaction is one of the most thoroughly studied signaling pathways primarily because of being implicated in sexual reproduction in mammals by way of maintaining gonadal function and sexual fertility. Despite material advances in understanding the role of point mutations, their mechanistic basis in FSH-FSHR signaling is still confined to mystically altered behavior of sTYS335 (sulfated tyrosine) yet lacking a substantial theory. To understand the structural basis of receptor modulation, we choose two behaviorally contradicting mutations, namely S128Y (activating) and D224Y (inactivating), found in FSH receptor responsible for ovarian hyperstimulation syndrome and ovarian dysgenesis, respectively. Using short-term molecular dynamics simulations, the atomic scale investigations reveal that the binding pattern of sTYS with FSH and movement of the thumb region of FSHR show distinct contrasting patterns in the two mutants, which supposedly could be a critical factor for differential FSHR behavior in activating and inactivating mutations.

Irigenin, a novel lead from Western Himalayan chemiome inhibits Fibronectin-Extra Domain A induced metastasis in Lung cancer cells.

Several lines of evidence indicate that Fibronectin Extra Domain A (EDA) promotes metastatic capacity of tumor cells by engaging cell surface α9ß1 integrins. This interaction mediated by the C-C loop of EDA activates pro-oncogenic signaling pathways leading to epithelial to mesenchymal transition (EMT) of tumor cells, thus signifying its importance in control of metastatic progression. In this context the present study was designed to explore the active compounds from selected ethno-medicinal plants of western Himalayan region for targeting EDA of Fibronectin in lung carcinoma cells. Structure based informatics for drug designing and screening was employed to generate a lead compound(s) feed that were conformationally and energetically viable. Out of 120 compounds selected, Irigenin showed best binding-affinity with C-C loop of EDA. Irigenin specifically targeted α9ß1 and α4ß1 integrin binding sites on EDA comprising LEU46, PHE47, PRO48, GLU58, LEU59 and GLN60 in its C-C loop as evaluated by energy decomposition per residue of Irigenin-EDA complex. In-vitro cell motility assays complemented with EDA knock-in and knockdown assays distinctively demonstrated that Irigenin prevents metastatic capacity of lung cancer cells by selectively blocking EDA. The results presented thus project Irigenin as a lead compound to overcome Fibronectin EDA induced metastatic progression in lung carcinoma cells.

A novel kinase mutation in VEGFR-1 predisposes its αC-helix/activation loop towards allosteric activation: Atomic insights from protein simulation.

Vascular endothelial growth factor receptor 1 (VEGFR-1) has been implicated in diverse pathologies, including cancers. Although VEGFR-1 is considered as functionally impaired kinase, its decoy characteristics make it an important regulator of VEGFR-mediated signaling, particularly in tumor angiogenesis. VEGFR-1 conveys signaling via its tyrosine kinase (TK) domain whose activation is regulated by phosphorylation of specific tyrosine residues. Thus dysregulation of VEGFR-1 signaling, as reported in most of the cancers, might be a consequence of altered phosphorylation that could be attributed to genotypic variations in its TK domain. Considering the importance of TK domain of VEGFR-1, we carried out its mutational screening in 84 clinically validated and histopathologically confirmed colorectal cancer patients. By means of direct DNA sequencing and SNP analyses, eight novel variations, including one synonymous, two deletion, one missense and four intronic variations, were reported in the TK domain of VEGFR-1. rs730882263:C>G variation specifically reported in colon cancer, representing a single-atomic change (Sulfur to Oxygen) in the predicted (p.Cys1110Ser) protein, was observed as potentially deleterious variation as assessed by multiple single-nucleotide polymorphism prediction servers. Molecular dynamics simulations of VEGFR-1 Wt and (p.Cys1110Ser) variant models revealed major conformational changes in variant protein presumptuously generating an open conformation thereby exposing the activation domain and consequently increasing the probability of phosphorylation events: a condition frequently reported in cancers.

Atomic Insight into the Altered O6-Methylguanine-DNA Methyltransferase Protein Architecture in Gastric Cancer.

O6-methylguanine-DNA methyltransferase (MGMT) is one of the major DNA repair protein that counteracts the alkalyting agent-induced DNA damage by replacing O6-methylguanine (mutagenic lesion) back to guanine, eventually suppressing the mismatch errors and double strand crosslinks. Exonic alterations in the form of nucleotide polymorphism may result in altered protein structure that in turn can lead to the loss of function. In the present study, we focused on the population feared for high exposure to alkylating agents owing to their typical and specialized dietary habits. To this end, gastric cancer patients pooled out from the population were selected for the mutational screening of a specific error prone region of MGMT gene. We found that nearly 40% of the studied neoplastic samples harbored missense mutation at codon151 resulting into Serine to Isoleucine variation. This variation resulted in bringing about the structural disorder, subsequently ensuing into a major stoichiometric variance in recognition domain, substrate binding and selectivity loop of the active site of the MGMT protein, as observed under virtual microscope of molecular dynamics simulation (MDS). The atomic insight into MGMT protein by computational approach showed a significant change in the intra molecular hydrogen bond pattern, thus leading to the observed structural anomalies. To further examine the mutational implications on regulatory plugs of MGMT that holds the protein in a DNA-Binding position, a MDS based analysis was carried out on, all known physically interacting amino acids essentially clustered into groups based on their position and function. The results generated by physical-functional clustering of protein indicated that the identified mutation in the vicinity of the active site of MGMT protein causes the local and global destabilization of a protein by either eliminating the stabilizing salt bridges in cluster C3, C4, and C5 or by locally destabilizing the "protein stabilizing hing" mapped on C3-C4 cluster, preceding the active site.

Design and Synthesis of Antitumor Heck-Coupled Sclareol Analogues: Modulation of BH3 Family Members by SS-12 in Autophagy and Apoptotic Cell Death.

Sclareol, a promising anticancer labdane diterpene, was isolated from Salvia sclarea. Keeping the basic stereochemistry-rich framework of the molecule intact, a method for the synthesis of novel sclareol analogues was designed using palladium(II)-catalyzed oxidative Heck coupling reaction in order to study their structure-activity relationship. Both sclareol and its derivatives showed an interesting cytotoxicity profile, with 15-(4-fluorophenyl)sclareol (SS-12) as the most potent analogue, having IC50 = 0.082 µM against PC-3 cells. It was found that SS-12 commonly interacts with Bcl-2 and Beclin 1 BH3 domain proteins and enhances autophagic flux by modulating autophagy-related proteins. Moreover, inhibition of autophagy by autophagy inhibitors protected against SS-12-induced apoptosis. Finally, SS-12 effectively suppressed tumor growth in vivo in Ehrlich's ascitic and solid Sarcoma-180 mouse models.

KAISO inhibition: an atomic insight.

In today's world, the pursuit of a novel anti-cancer agent remains top priority because of the fact that the global burden of this malady is continuously increasing. Our work is no different from others in searching for new therapeutic solutions. To achieve this, we are looking into Epigenetics, the phenomenon governed by hypermethylation and hypomethylation of tumor suppressor genes and oncogenes, respectively. Our target for this study is an important intermediary methyl-CpG binding protein named kaiso. In our study, we have used the X-ray crystallographic structure of Kaiso for virtual screening and molecular dynamics simulations to study the binding modes of possible inhibitors. The C2H2 domain comprising LYS539 was used for screening the inter bio screen Database having 48,531 natural compounds. Our approach of using computer-aided drug designing methods helped us to remove the execrable compounds and narrowed our focus on a selected few for molecular simulation studies. The top ranked compound (chem. ID 28127) exhibited the highest binding affinity and was also found to be stable throughout the 20 ns timeframe. This compound is therefore a good starting point for developing strong inhibitors.