Novel pyrano 1,3 oxazine based ligand inhibits the epigenetic reader hBRD2 in glioblastoma.

Glioblastoma (GBM) is the most common primary brain malignancy, rarely amenable to treatment with a high recurrence rate. GBM are prone to develop resistance to the current repertoire of drugs, including the first-line chemotherapeutic agents with frequent recurrence, limiting therapeutic success. Recent clinical data has evidenced the BRD2 and BRD4 of the BET family proteins as the new druggable targets against GBM. In this relevance, we have discovered a compound (pyrano 1,3 oxazine derivative; NSC 328111; NS5) as an inhibitor of hBRD2 by the rational structure-based approach. The crystal structure of the complex, refined to 1.5 Šresolution, revealed that the NS5 ligand significantly binds to the N-terminal bromodomain (BD1) of BRD2 at the acetylated (Kac) histone binding site. The quantitative binding studies, by SPR and MST assay, indicate that NS5 binds to BD1 of BRD2 with a KD value of ∼1.3 µM. The cell-based assay, in the U87MG glioma cells, confirmed that the discovered compound NS5 significantly attenuated proliferation and migration. Furthermore, evaluation at the translational level established significant inhibition of BRD2 upon treatment with NS5. Hence, we propose that the novel lead compound NS5 has an inhibitory effect on BRD2 in glioblastoma.

Electrostatic deposition assisted preparation, characterization and evaluation of chrysin liposomes for breast cancer treatment.

Chrysin (CHR), a flavone found in multiple vegetables, fruits and mushrooms has been explored so far as a neurotropic, anti-inflammatory and anti-cancer biomolecule. Despite the stated therapeutic potential, low solubility and bioavailability limit its therapeutic benefit. To circumvent these drawbacks, development of chrysin liposomes (CLPs) is reported in the present investigation. The CLPs were developed by electrostatic deposition assisted film hydration method using chitosan/lecithin to protect chrysin in the nano-lipoidal shell. Developed CLPs were extensively characterized by DSC, XPRD, FE-SEM, TEM, particle size, polydispersity index, zeta potential, percent drug loading and encapsulation efficiency. These CLPs were further characterized by in vitro dissolution, in vivo bioavailability, in vitro anticancer and stability study. Suitable particle size, PDI and ZP implying stabilization of developed CLPs. The % DL and % EE was found to be 3.56 ± 0.13 and 90.5 ± 1.49 respectively. DSC and PXRD study revealed amorphous transition of CHR, which may help to increase its solubility and dissolution profile. In vivo pharmacokinetic study demonstrated more than 5-fold increase in relative bioavailability of CLPs. The in silico molecular docking study results demonstrated the electrostatic interaction between two polymers. The present study suggests that chitosan could protect and encapsulate chrysin which eventually enhances its cytotoxicity as well as bioavailability.

A key role by polymers in microneedle technology: a new era.

The skin serves as the major organ in the targeted transdermal drug delivery system for many compounds. The microneedle acts as a novel technique to deliver drugs across the different layers of the skin, including the major barrier stratum corneum, in an effective manner. A microneedle array patch comprises dozens to hundreds of micron-sized needles with numerous structures and advantages resulting from their special and smart designs. The microneedle approach is much more advanced than conventional transdermal delivery pathways due to several benefits like minimally invasive, painless, self-administrable, and enhanced patient compliance. The microneedles are classified into hollow, solid, coated, dissolving, and hydrogel. Several polymers are used to fabricate microneedle, such as natural, semi-synthetic, synthetic, biodegradable, and swellable polymers. Researchers in the preparation of microneedles also explored the combinations of polymers. The safety of the polymer used in microneedle is a crucial aspect to prevent toxicity in vivo. Thus, this review aims to provide a detailed review of microneedles and mainly focus on the various polymers used in the fabrication of microneedles.

Computational studies and biosensory applications of graphene-based nanomaterials: a state-of-the-art review.

Graphene, graphene oxide (GO) and graphene quantum dots (GQDs) are expected to play a vital role in the diagnosis of severe ailments. Computer-based simulation approaches are helpful for understanding theoretical tools prior to experimental investigation. These theoretical tools still have a high computational requirement. Thus, more efficient algorithms are required to perform studies on even larger systems. The present review highlights the recent advancement in structural confinement using computer simulation approaches along with biosensory applications of graphene-based materials. The computer simulation approaches help to identify the interaction between interacting molecules and sensing elements like graphene sheets. The simulation approach reduces the wet-lab experiment time and helps to predict the interaction and interacting environment. The experimental investigation can be tuned at a molecular level easily to predict small changes in structural configuration. Here, the molecular simulation study could be useful as an alternative to actual wet experimental approaches. The sensing ability of graphene-based materials is a result of interactions like hydrogen bonding, base-base interaction, and base-to-pi interaction to name a few. These interactions help in designing and engineering a substrate for sensing of various biomolecules.

Recent Advancement in Bio-precursor derived graphene quantum dots: Synthesis, Characterization and Toxicological Perspective.

Graphene quantum dots (GQDs), impressive materials with enormous future potential, are reviewed from their inception, including different precursors. Considering the increasing burden of industrial and ecological bio-waste, there is an urgency to develop techniques which will convert biowaste into active moieties of interest. Amongst the various materials explored, we selectively highlight the use of potential carbon containing bioprecursors (e.g. plant-based, amino acids, carbohydrates), and industrial waste and its conversion into GQDs with negligible use of chemicals. This review focuses on the effects of different processing parameters that affect the properties of GQDs, including the surface functionalization, paradigmatic characterization, toxicity and biocompatibility issues of bioprecursor derived GQDs. This review also examines current challenges and s the ongoing exploration of potential bioprecursors for ecofriendly GQD synthesis for future applications. This review sheds further light on the electronic and optical properties of GQDs along with the effects of doping on the same. This review may aid in future design approaches and applications of GQDs in the biomedical and materials design fields.

Biochemical insight into pseudouridine synthase 7 (PUS7) as a novel interactor of sirtuin, SIRT1.

Sirtuin1 (SIRT1) forms a dynamic regulatory network with multiple proteins. The SIRT1 protein interactome comprises histone, non-histone substrates, and modulators of SIRT1 deacetylase. Proteomic studies have enlisted several proteins in SIRT1 network, but the structural and functional details of their interactions remain largely unexplored. In this study, we establish Pseudouridine synthase 7 (PUS7), a nuclear protein involved in stem cell development and intellectual disabilities, as a novel interactor of SIRT1. The binding regions are predicted and analyzed based on molecular docking studies. The direct interaction occurs between SIRT1 and PUS7, as evidenced by pull-down studies and surface plasmon resonance (SPR) assay. Furthermore, the truncation studies unambiguously suggested that the N-terminal region of PUS7 is essential for forming a stable complex with SIRT1. Overall, our results suggest that PUS7 may regulate the SIRT1 function when it directly interacts with SIRT1.

Design, synthesis, in-vitro evaluation and molecular docking studies of novel indole derivatives as inhibitors of SIRT1 and SIRT2.

Sirtuins (SIRTs), class III HDAC (Histone deacetylase) family proteins, are associated with cancer, diabetes, and other age-related disorders. SIRT1 and SIRT2 are established therapeutic drug targets by regulating its function either by activators or inhibitors. Compounds containing indole moiety are potential lead molecules inhibiting SIRT1 and SIRT2 activity. In the current study, we have successfully synthesized 22 indole derivatives in association with an additional triazole moiety that provide better anchoring of the ligands in the binding cavity of SIRT1 and SIRT2. In-vitro binding and deacetylation assays were carried out to characterize their inhibitory effects against SIRT1 and SIRT2. We found four derivatives, 6l, 6m, 6n, and 6o to be specific for SIRT1 inhibition; three derivatives, 6a, 6d and 6k, specific for SIRT2 inhibition; and two derivatives, 6s and 6t, which inhibit both SIRT1 and SIRT2. In-silico validation for the selected compounds was carried out to study the nature of binding of the ligands with the neighboring residues in the binding site of SIRT1. These derivatives open up newer avenues to explore specific inhibitors of SIRT1 and SIRT2 with therapeutic implications for human diseases.

Evaluation of novel TGR5 agonist in combination with Sitagliptin for possible treatment of type 2 diabetes.

TGR5 is a member of G protein-coupled receptor (GPCR) superfamily, a promising molecular target for metabolic diseases. Activation of TGR5 promotes secretion of glucagon-like peptide-1 (GLP-1), which activates insulin secretion. A series of 2-thio-imidazole derivatives have been identified as novel, potent and orally efficacious TGR5 agonists. Compound 4d, a novel TGR5 agonist, in combination with Sitagliptin, a DPP-4 inhibitor, has demonstrated an adequate GLP-1 secretion and glucose lowering effect in animal models, suggesting a potential clinical option in treatment of type-2 diabetes.

Crystal structure of the MazG-related nucleoside triphosphate pyrophosphohydrolase from Thermotoga maritima MSB8.

The MazG family proteins, which are highly conserved in bacteria, are nucleoside triphosphate pyrophosphohydrolases that hydrolyze all canonical nucleoside triphosphates, and are also involved in removing noncanonical nucleoside triphosphates to prevent their incorporation into DNA or RNA. The primary structure of TM0360 from Thermotoga maritima MSB8 suggested that TM0360 is a MazG-related nucleoside triphosphate pyrophosphohydrolase. The crystal structure of the TM0360 protein was determined by the MAD technique at 2.0 Å resolution. The asymmetric unit contains an intact dimer molecule. The overall structure of TM0360 is similar to the known structures of the dimeric MazG protein and dUTPases. The putative NTP binding pocket in TM0360, identified by considering the probable NTP-interacting residues and structural features, suggested that TM0360 resembles the C-terminal domain of Escherichia coli MazG, although TM0360 may be a truncated paralog of the N-terminal domain of T. maritima MazG (TM0913), according to its primary structure. The putative function of TM0360 is discussed, based on structural homology.

Long circulating self-assembled nanoparticles from cholesterol-containing brush-like block copolymers for improved drug delivery to tumors.

Amphiphilic brush-like block copolymers composed of polynorbonene-cholesterol/poly(ethylene glycol) (P(NBCh9-b-NBPEG)) self-assembled to form a long circulating nanostructure capable of encapsulating the anticancer drug doxorubicin (DOX) with high drug loading (22.1% w/w). The release of DOX from the DOX-loaded P(NBCh9-b-NBPEG) nanoparticles (DOX-NPs) was steady at less than 2% per day in PBS. DOX-NPs were effectively internalized by human cervical cancer cells (HeLa) and showed dose-dependent cytotoxicity, whereas blank nanoparticles were noncytotoxic. The DOX-NPs demonstrated a superior in vivo circulation time relative to that of free DOX. Tissue distribution and in vivo imaging studies showed that DOX-NPs preferentially accumulated in tumor tissue with markedly reduced accumulation in the heart and other vital organs. The DOX-NPs greatly improved survival and significantly inhibited tumor growth in tumor-bearing SCID mice compared to that for the untreated and free DOX-treated groups. The results indicated that self-assembled P(NBCh9-b-NBPEG) may be a useful carrier for improving tumor delivery of hydrophobic anticancer drugs.

Nanoarchitectonics in cancer therapy and imaging diagnosis.

Nanoarchitectonics has gained remarkable importance due to the fabrication of various recent nanostructures with the capability of being used in biomedical science, particularly in cancer diagnosis and treatment. These nanosized structures possess unique physical and optical properties that can be exploited for cancer therapeutics, and so nanoarchitectonics is popularly known as nanomedicine. The goal of this review is to discuss the latest findings in nanostructures research including nanocrystals, nanotubes, nanoshells, nanopillars, nanoballs, nanoflowers, nanorods, nanocontainers, nanobelts, nanocages, nanodiscs, nanodots, nanoprisms, nanoplates, nanorings, nanocubes, nanobranches, nanospheres, nanorattles, nanostars, nanotrees, nanowires, nanowalls, nanodiamonds, nanosheets, layered nanostructures, quantum dots, mesoporous nanostructures etc. in the field of cancer therapy and imaging. This review further highlights brief information about use of radionuclide in cancer. Lastly, different nanoformulations that are available in the market or are under clinical trials for cancer therapy and imaging are discussed.

Applying quality by design (QbD) concept for fabrication of chitosan coated nanoliposomes.

In the present investigation, a quality by design (QbD) strategy was successfully applied to the fabrication of chitosan-coated nanoliposomes (CH-NLPs) encapsulating a hydrophilic drug. The effects of the processing variables on the particle size, encapsulation efficiency (%EE) and coating efficiency (%CE) of CH-NLPs (prepared using a modified ethanol injection method) were investigated. The concentrations of lipid, cholesterol, drug and chitosan; stirring speed, sonication time; organic:aqueous phase ratio; and temperature were identified as the key factors after risk analysis for conducting a screening design study. A separate study was designed to investigate the robustness of the predicted design space. The particle size, %EE and %CE of the optimized CH-NLPs were 111.3 nm, 33.4% and 35.2%, respectively. The observed responses were in accordance with the predicted response, which confirms the suitability and robustness of the design space for CH-NLP formulation. In conclusion, optimization of the selected key variables will help minimize the problems related to size, %EE and %CE that are generally encountered when scaling up processes for NLP formulations. The robustness of the design space will help minimize both intra-batch and inter-batch variations, which are quite common in the pharmaceutical industry.

Development of an Analytical Quality by Design RP-HPLC Method and Its Validation for Estimation of Gefitinib From Bulk, Tablet Dosage Form, and Complex Nanoformulation.

BACKGROUND: Estimation of the drug and development of the method is a critical aspect of formulation development and a critical factor for analytical scientists. Gefitinib is a poorly soluble anticancer drug. OBJECTIVE: The present research focuses on the topic of the development of innovative quality by design methods for the estimation of gefitinib (GF) from bulk, pharmaceutical tablet formulation, and complex nanoformulations. METHODS: To simplify the estimation of poorly soluble drugs such as GF, response surface methodology (RSM) was adopted with effective leverages to obtain precise computation design space using the Box-Behnken design (BBD) model. The major three mixed-effect independent factors (percentage of buffer, pH of buffer, and flow rate) were screened with three prominent dependent responses (viz., theoretical plate, retention time, and tailing factor) selected for optimal analysis. Furthermore, co-processed steps were employed for the estimation of the analyte from the complex formulation. RESULTS: The RP-HPLC method uses the quality by design (QbD) approach can effectively estimate the analyte concentration of less than 4.5 min. The developed method was economically robust and sensitive and shows a relative standard deviation (RSD, %) of less than 2% for all the selected validation parameters. The estimated design space suggests the highest desirability (R2-0.998) at 60% of buffer in the mobile phase, pH 4.25, and flow rate of 0.7 mL/min. CONCLUSIONS: The QbD approach was used to design and develop the method by understanding the interaction between dependent and independent variables to get the optimum values. The developed method was validated successfully and can be useful for formulation scientists to estimate drug concentration and drug release profiles from complex nanoformulations. HIGHLIGHTS: The analytical approach was designed and quantified using a quality-by-design approach to make the RP-HPLC method more robust and efficient for the estimation of analytes from complex nanoformulations. The method is also useful to eliminate the interfering molecule during estimation by employing co-processing steps. The developed method saves time and cost of solvent and employs QbD as a requirement of recent regulatory concern.

A comprehensive review on synthesis and designing aspects of coumarin derivatives as monoamine oxidase inhibitors for depression and Alzheimer's disease.

Monoamine oxidase (MAO) enzyme inhibition is a crucial target for the management of depression and Alzheimer disease and inhibitors of MAO are the most important drugs for their management. Coumarins are a large family of compounds, of natural and synthetic origin, that exhibit a variety of pharmacological activities, including MAO inhibition. The current review highlights the design and synthetic methods of coumarin derivatives as well as coumarins obtained from plant source as MAO inhibitors for treatment of depression and Alzheimer disease with salient finding related to structure-activity relationship. The aim of present review is to find out natural as well as synthetic coumarins as MAO inhibitors.

In vitro and in vivo consideration of novel environmentally responsive ophthalmic drug delivery system.

In the present study, novel environmentally responsive ophthalmic drug delivery system composed of two gelling polymers with different phase transition mechanisms was developed in order to obtain sustained drug release in ocular cavity. Combination of polyacrylic acid (carbopol 934P) and xanthan gum was investigated as ophthalmic vehicle and assessed for its in vitro and in vivo performance. Different ratios of these polymers were used to prepare environmentally responsive ophthalmic drug delivery system by simple mixing procedure. Developed formulation was assessed for physical tests such as appearance/clarity, pH, gelation; and performance characteristics such as drug content, rheological measurement, in vitro release, antimicrobial efficiency, in vivo studies for eye irritation, residence time estimation. Prepared formulation showed agreeable appearance/clarity, acceptable pH and good gelation property. In vitro and in vivo studies demonstrated adequate drug content, desired rheological behavior and reasonable in vitro and in vivo drug release property. In conclusion, the optimum concentration of polymers results in increased residence time and sustained drug release. On the basis of these findings, environmentally responsive system based on combination of carbopol and xanthan gum may be considered as a promising tool for ophthalmic delivery.

Design and statistical optimization of osmotically driven capsule based on push-pull technology.

In present investigation attempt was made to develop and statistically optimize osmotically active capsule tailor made from the concept of bilayer (push-pull) osmotic tablet technology. The capsule was comprised of active (drug) and push (osmogen) layer. Active layer was compressed in form of tablet by mixing known amount of drug and formulation excipients. Similarly push layer was made by compressing Mannitol with formulation excipients. Finally, both layers were packed in hard gelatin capsule having small aperture at top and coated with semipermeable membrane to form osmotically active capsule. Formulated and optimized capsules were characterized for Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC), scanning electron microscopy, In-vitro drug release study and Release models and kinetics. Statistically optimized formulation showed good correlation between predicted and experimented results, which further confirms the practicability and validity of the model.

Chlorhexidine as a Keap1-Nrf2 inhibitor: a new target for an old drug for Parkinson's disease therapy.

Oxidative stress plays a vital role in the pathophysiology of most neurodegenerative diseases such as Parkinson's disease (PD). The Keap1-Nrf2-ARE pathway, one of the internal defense mechanisms, curbs the reactive oxygen species (ROS) generated in the cellular environment. The pathway leads to the expression of antioxidant genes such as HO-1, GCLC, and NQO1, which act as cellular redox switches and protect the cellular environment. Keap1, the negative regulator of Nrf2, is a potential therapeutic target for treating age-related neurodegenerative diseases. Tecfidera (Dimethyl fumarate), used in the intervention for relapsing multiple sclerosis, is the only commercial drug known to regulate the Nrf2 function. Here, we have identified a repurposing drug, chlorhexidine (LBP125), through ligand-based pharmacophore development and screening against the DrugBank, as a potential inhibitor of the ß-propeller domain of Keap1 (Keap1-DC). Chlorhexidine, an antimicrobial agent, is widely used as a mouthwash, skin cleanser, and intervening bacterial infection during childbirth. The biochemical assay confirmed a significant binding affinity of 30 µM and competitively inhibited the Nrf2 peptide interaction. Moreover, chlorhexidine also exerts cytoprotection in a neurotoxic cell model of PD through Keap1-Nrf2 disruption leading to nuclear translocation of Nrf2 and expression of downstream genes, HO-1, and NQO1. Hence, the chemical scaffold of chlorhexidine is a potential lead to develop new chemical libraries with drug-like properties for treating PD.Communicated by Ramaswamy H. Sarma.

Structural and biochemical insights into purine-based drug molecules in hBRD2 delineate a unique binding mode opening new vistas in the design of inhibitors of the BET family.

The bromodomain and extra-terminal (BET) family proteins, which are involved in chromatin function, have been shown to be promising drug targets in several pathological conditions, including cancer and inflammation. There is considerable interest in the development of BET inhibitors with novel scaffolds to modulate the epigenesis of such diseases. Here, high-resolution crystal structures of the purine class of FDA-approved drugs (theophylline, doxophylline and acyclovir) and non-FDA-approved compounds (3-methyl-7-propylxanthine and theobromine) complexed with hBRD2 bromodomains BD1 and BD2 are reported. Remarkably, a new binding site is exhibited by stacking the compounds against the WPF shelf of BD1 and BD2. This serendipitous binding, in addition to the known acetyl-lysine binding site, sufficiently anchors the ligands in the solvent-exposed region. In addition, slight variations in the lipophilicity of these molecules significantly affected the in vitro binding affinity and selectivity towards BD1 compared with BD2. This idiosyncratic binding provides a new structural framework to link these sites for the development of next-generation inhibitors of the BET family.

Hierarchically structured free-standing hydrogels with liquid crystalline domains and magnetic nanoparticles as dual physical cross-linkers.

Here we report a modular strategy for preparing physically cross-linked and mechanically robust free-standing hydrogels comprising unique thermotropic liquid crystalline (LC) domains and magnetic nanoparticles both of which serve as the physical cross-linkers resulting in hydrogels that can be used as magnetically responsive soft actuators. A series of amphiphilic LC pentablock copolymers of poly(acrylic acid) (PAA), poly(5-cholesteryloxypentyl methacrylate) (PC5MA), and poly(ethylene oxide) (PEO) blocks in the sequence of PAA-PC5MA-PEO-PC5MA-PAA were prepared using reversible addition-fragmentation chain transfer polymerization. These pentablock copolymers served as macromolecular ligands to template Fe(3)O(4) magnetic nanoparticles (MNPs), which were directly anchored to the polymer chains through the coordination bonds with the carboxyl groups of PAA blocks. The resulting polymer/MNP nanocomposites comprised a complicated hierarchical structure in which polymer-coated MNP clusters were dispersed in a microsegregated pentablock copolymer matrix that further contained LC ordering. Upon swelling, the hierarchical structure was disrupted and converted to a network structure, in which MNP clusters were anchored to the polymer chains and LC domains stayed intact to connect solvated PEO and PAA blocks, leading to a free-standing LC magnetic hydrogel (LC ferrogel). By varying the PAA weight fraction (f(AA)) in the pentablock copolymers, the swelling degrees (Q) of the resulting LC ferrogels were tailored. Rheological experiments showed that these physically cross-linked free-standing LC ferrogels exhibit good mechanical strength with storage moduli G' of around 10(4)-10(5) Pa, similar to that of natural tissues. Furthermore, application of a magnetic field induced bending actuation of the LC ferrogels. Therefore, these physically cross-linked and mechanically robust LC ferrogels can be used as soft actuators and artificial muscles. Moreover, this design strategy is a versatile platform for incorporation of different types of nanoparticles (metallic, inorganic, biological, etc.) into multifunctional amphiphilic block copolymers, resulting in unique free-standing hybrid hydrogels of good mechanical strength and integrity with tailored properties and end applications.

Structural investigation of a pyrano-1,3-oxazine derivative and the phenanthridinone core moiety against BRD2 bromodomains.

The BET (bromodomain and extra-terminal) family of proteins recognize the acetylated histone code on chromatin and play important roles in transcriptional co-regulation. BRD2 and BRD4, which belong to the BET family, are promising drug targets for the management of chronic diseases. The discovery of new scaffold molecules, a pyrano-1,3-oxazine derivative (NSC 328111; NS5) and phenanthridinone-based derivatives (L10 and its core moiety L10a), as inhibitors of BRD2 bromodomains BD1 and BD2, respectively, has recently been reported. The compound NS5 has a significant inhibitory effect on BRD2 in glioblastoma. Here, the crystal structure of BRD2 BD2 in complex with NS5, refined to 2.0 Šresolution, is reported. Moreover, as the previously reported crystal structures of the BD1-NS5 complex and the BD2-L10a complex possess moderate electron density corresponding to the respective ligands, the crystal structures of these complexes were re-evaluated using new X-ray data. Together with biochemical studies using wild-type BRD2 BD1 and BD2 and various mutants, it is confirmed that the pyrano-1,3-oxazine and phenanthridinone derivatives are indeed potent inhibitors of BRD2 bromodomains.