SMALPs Are Not Simply Nanodiscs: The Polymer-to-Lipid Ratios of Fractionated SMALPs Underline Their Heterogeneous Nature.

Amphipathic styrene-maleic acid (SMA) copolymers directly solubilize biomembranes into SMA-lipid particles, or SMALPs, that are often regarded as nanodiscs and hailed as a native membrane platform. The promising outlook of SMALPs inspires the discovery of many SMA-like copolymers that also solubilize biomembranes into putative nanodiscs, but a fundamental question remains on how much the SMALPs or SMALP analogues truly resemble the bilayer structure of nanodiscs. This unfortunate ambiguity undermines the utility of SMA or SMA-like copolymers in membrane biology because the structure and function of many membrane proteins depend critically on their surrounding matrices. Here, we report the structural heterogeneity of SMALPs revealed through fractionating SMALPs comprised of lipids and well-defined SMAs via size-exclusion chromatography followed by quantitative determination of the polymer-to-lipid (P/L) stoichiometric ratios in individual fractions. Through the lens of P/L stoichiometric ratios, different self-assembled polymer-lipid nanostructures are inferred, such as polymer-remodeled liposomes, polymer-encased nanodiscs, polymer-lipid mixed micelles, and lipid-doped polymer micellar aggregates. We attribute the structural heterogeneity of SMALPs to the microstructure variations amongst individual polymer chains that give rise to their polydisperse detergency. As an example, we demonstrate that SMAs with a similar S/MA ratio but different chain sizes participate preferentially in different polymer-lipid nanostructures. We further demonstrate that proteorhodopsin, a light-driven proton pump solubilized within the same SMALPs is distributed amongst different self-assembled nanostructures to display different photocycle kinetics. Our discovery challenges the native nanodisc notion of SMALPs or SMALP analogues and highlights the necessity to separate and identify the structurally dissimilar polymer-lipid particles in membrane biology studies.

Delivery of gene editing therapeutics.

For the past decades, gene editing demonstrated the potential to attenuate each of the root causes of genetic, infectious, immune, cancerous, and degenerative disorders. More recently, Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-associated protein 9 (CRISPR-Cas9) editing proved effective for editing genomic, cancerous, or microbial DNA to limit disease onset or spread. However, the strategies to deliver CRISPR-Cas9 cargos and elicit protective immune responses requires safe delivery to disease targeted cells and tissues. While viral vector-based systems and viral particles demonstrate high efficiency and stable transgene expression, each are limited in their packaging capacities and secondary untoward immune responses. In contrast, the nonviral vector lipid nanoparticles were successfully used for as vaccine and therapeutic deliverables. Herein, we highlight each available gene delivery systems for treating and preventing a broad range of infectious, inflammatory, genetic, and degenerative diseases. STATEMENT OF SIGNIFICANCE: CRISPR-Cas9 gene editing for disease treatment and prevention is an emerging field that can change the outcome of many chronic debilitating disorders.

Nanodiscs: a versatile nanocarrier platform for cancer diagnosis and treatment.

Cancer therapy is a significant challenge due to insufficient drug delivery to the cancer cells and non-selective killing of healthy cells by most chemotherapy agents. Nano-formulations have shown great promise for targeted drug delivery with improved efficiency. The shape and size of nanocarriers significantly affect their transport inside the body and internalization into the cancer cells. Non-spherical nanoparticles have shown prolonged blood circulation half-lives and higher cellular internalization frequency than spherical ones. Nanodiscs are desirable nano-formulations that demonstrate enhanced anisotropic character and versatile functionalization potential. Here, we review the recent development of theranostic nanodiscs for cancer mitigation ranging from traditional lipid nanodiscs encased by membrane scaffold proteins to newer nanodiscs where either the membrane scaffold proteins or the lipid bilayers themselves are replaced with their synthetic analogues. We first discuss early cancer detection enabled by nanodiscs. We then explain different strategies that have been explored to carry a wide range of payloads for chemotherapy, cancer gene therapy, and cancer vaccines. Finally, we discuss recent progress on organic-inorganic hybrid nanodiscs and polymer nanodiscs that have the potential to overcome the inherent instability problem of lipid nanodiscs.

Design of Hedgehog pathway inhibitors for cancer treatment.

Hedgehog (Hh) signaling is involved in the initiation and progression of various cancers and is essential for embryonic and postnatal development. This pathway remains in the quiescent state in adult tissues but gets activated upon inflammation and injuries. Inhibition of Hh signaling pathway using natural and synthetic compounds has provided an attractive approach for treating cancer and inflammatory diseases. While the majority of Hh pathway inhibitors target the transmembrane protein Smoothened (SMO), some small molecules that target the signaling cascade downstream of SMO are of particular interest. Substantial efforts are being made to develop new molecules targeting various components of the Hh signaling pathway. Here, we have discussed the discovery of small molecules as Hh inhibitors from the diverse chemical background. Also, some of the recently identified natural products have been included as a separate section. Extensive structure-activity relationship (SAR) of each chemical class is the focus of this review. Also, clinically advanced molecules are discussed from the last 5 to 7 years. Nanomedicine-based delivery approaches for Hh pathway inhibitors are also discussed concisely.

Recent advances in spirocyclization of indole derivatives.

Spiroindolines and spiroindoles are an important class of spirocyclic compounds present in a wide range of pharmaceuticals and biologically important natural alkaloids. Various spiroindolines and spiroindoles possess versatile reactivity which enables them to act as precursors for other privileged heterocycles. In view of the importance of this scaffold, many researchers focused their efforts to develop facile and mild synthetic methods for spirocyclization of indoles. However, the synthesis of spiroindolines and spiroindoles is known to be difficult due to rapid 1,2-migration to restore aromaticity. This review aims to briefly discuss the latest developments to access highly functionalized spiroindolines and spiroindoles to stimulate further research in the field to find new and efficient methodologies for accessing new spiroindolines and spiroindoles.

Animal models of hepatotoxicity.

INTRODUCTION: Liver is the largest and important organ in the body, involved in the metabolism of food and drugs. Liver diseases are potentially life threatening for humans. The etiology of liver disorder varied due to different reasons like autoimmune disorder, viral infection, toxic chemical, and due to changing diet style. Liver injury produces pathological changes like increase level of SGOT, SGPT, TB and generation of free radical radicals. METHODS: A better understanding of primary mechanisms is mandatory for designing of new therapeutic drugs. Therefore, animal models are being developed to mimic human liver diseases. Animal models are being used for several decades to study the pathogenesis of liver disorders and related toxicities. CONCLUSION: In this review, we revealed various animal models with their merits and demerits. Our main focus is to explore all new and traditional animal models under broad classification like non-invasive, invasive and genetic models which directly or indirectly produce hepatotoxicity.

Recent advances in the chemistry and biology of benzothiazoles.

Benzothiazole is a privileged heterocyclic scaffold having a benzene ring fused with a five-membered thiazole ring. This moiety has attracted considerable attention because of its wide range of pharmacological activities such as antitubercular, antimicrobial, antimalarial, anticonvulsant, anthelmintic, analgesic, anti-inflammatory, antidiabetic, antitumor activity, etc. In the last few years, some novel benzothiazoles have been developed with varied biological activities. To access this scaffold in high yield and to introduce diversity, a variety of new synthetic methods have been invented. In this review, we highlight the development of novel benzothiazoles for various biological activities along with the best synthetic protocols for their synthesis.

C-N bond forming cross-coupling reactions: an overview.

Nitrogen containing compounds are of great importance because of their interesting and diverse biological activities. The construction of the C-N bond is of significant importance as it opens avenues for the introduction of nitrogen in organic molecules. Despite significant advancements in this field, the construction of the C-N bond is still a major challenge for organic chemists, due to the involvement of harsh reaction conditions or the use of expensive catalysts in many cases. Thus, it is a challenge to develop alternative, milder and cheaper methodologies for the construction of C-N bonds. Herein, we have selected some prime literature reports that may serve this purpose.

Hydrophilic nanoparticles that kill bacteria while sparing mammalian cells reveal the antibiotic role of nanostructures.

To dissect the antibiotic role of nanostructures from chemical moieties belligerent to both bacterial and mammalian cells, here we show the antimicrobial activity and cytotoxicity of nanoparticle-pinched polymer brushes (NPPBs) consisting of chemically inert silica nanospheres of systematically varied diameters covalently grafted with hydrophilic polymer brushes that are non-toxic and non-bactericidal. Assembly of the hydrophilic polymers into nanostructured NPPBs doesn't alter their amicability with mammalian cells, but it incurs a transformation of their antimicrobial potential against bacteria, including clinical multidrug-resistant strains, that depends critically on the nanoparticle sizes. The acquired antimicrobial potency intensifies with small nanoparticles but subsides quickly with large ones. We identify a threshold size (dsilica ~ 50 nm) only beneath which NPPBs remodel bacteria-mimicking membrane into 2D columnar phase, the epitome of membrane pore formation. This study illuminates nanoengineering as a viable approach to develop nanoantibiotics that kill bacteria upon contact yet remain nontoxic when engulfed by mammalian cells.

pH-sensitive nanomedicine of novel tubulin polymerization inhibitor for lung metastatic melanoma.

Microtubule binding agents such as paclitaxel and vincristine have activity in metastatic melanoma. However, even responsive tumors develop resistance, highlighting the need to investigate new drug molecules. Here, we showed that a new compound, CH-2-102, developed by our group, has high anti-tumor efficacy in human and murine melanoma cells. We confirmed that CH-2-102 robustly suppresses the microtubule polymerization process by directly interacting with the colchicine binding site. Our results unveil that CH-2-102 suppresses microtubule polymerization and subsequently induces G2 phase cell arrest as one of the possible mechanisms. Notably, CH-2-102 maintains its efficacy even in the paclitaxel resistance melanoma cells due to different binding sites and a non-Pgp substrate. We developed a pH-responsive drug-polymer Schiff bases linker for high drug loading into nanoparticles (NPs). Our CH-2-102 conjugated NPs induced tumor regression more effectively than Abraxane® (Nab-paclitaxel, N-PTX), free drug, and non-sensitive NPs in B16-F10 cell-derived lung metastasis mouse model. Furthermore, our results suggest that the formulation has a high impact on the in vivo efficacy of the drug and warrants further investigation in other cancers, particularly taxane resistant. In conclusion, the microtubule polymerization inhibitor CH-2-102 conjugated pH-responsive NPs induce tumor regression in lung metastasis melanoma mice, suggesting it may be an effective strategy for treating metastatic melanoma.

Nanoformulation design and therapeutic potential of a novel tubulin inhibitor in pancreatic cancer.

Successful treatment of pancreatic cancer remains a challenge due to desmoplasia, development of chemoresistance, and systemic toxicity. Herein, we synthesized (6-(3-hydroxy-4-methoxylphenyl)pyridin-2-yl) (3,4,5-trimethoxyphenyl)methanone (CH-3-8), a novel microtubule polymerization inhibitor with little susceptible to transporter-mediated chemoresistance. CH-3-8 binding to the colchicine-binding site in tubulin protein was confirmed by tubulin polymerization assay and molecular modeling. CH-3-8 disrupted microtubule dynamics at the nanomolar concentration in MIA PaCa-2 and PANC-1 pancreatic cancer cell lines. CH-3-8 significantly inhibited the proliferation of these cells, induced G2/M cell cycle arrest, and led to apoptosis. CH-3-8 is hydrophobic with an aqueous solubility of 0.97 ± 0.16 µg/mL at pH 7.4. We further conjugated it with dodecanol through diglycolate linker to increase hydrophobicity and thus loading in lipid-based delivery systems. Hence, we encapsulated CH-3-8 lipid conjugate (LDC) into methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol) (mPEG-b-PCC-g-DC) polymeric nanoparticles (NPs) by solvent evaporation, resulting in a mean particle size of 125.6 ± 2.3 nm and drug loading of 10 ± 1.0% (w/w) while the same polymer could only load 1.6 ± 0.4 (w/w) CH-3-8 using the same method. Systemic administration of 6 doses of CH-3-8 and LDC loaded NPs at the dose of 20 mg/kg into orthotopic pancreatic tumor-bearing NSG mice every alternate day resulted in significant tumor regression. Systemic toxicity was negligible, as evidenced by histological evaluations. In conclusion, CH-3-8 LDC loaded NPs have the potential to improve outcomes of pancreatic cancer by overcoming transporter-mediated chemoresistance and reducing systemic toxicity.

Functional similarity of modified cascade impactor to deposit drug particles on cells.

Pulmonary drug delivery is a non-invasive and effective route for local or systemic drug administration. Despite several products in the market, the mechanism of drug absorption from the lungs is not well understood. An in vitro model for aerosol deposition and transport across epithelia that uses particle deposition may be a good predictor of and help understand in vivo drug disposition. The objective of this study was to examine the uptake of HFA fluticasone (Flovent HFA) particles at various stages of the Next Generation Impactor (NGI) by human Calu-3 cell line derived from human bronchial respiratory epithelial cell monolayer. Particles were directly deposited on Calu-3 cells incorporated onto stages 3, 5, and 7 of the NGI at the air-liquid interface (ALI). We modified the NGI apparatus to allow particle deposition directly on cells and determined the in vitro deposition characteristics using modified NGI. Particles of different size ranges showed different in vitro epithelial transport rates. This study highlights the need to develop in vitro test systems to determine the deposition of aerosol particles on cell monolayers by simultaneously considering aerodynamic properties.

Nanoparticulate delivery of potent microtubule inhibitor for metastatic melanoma treatment.

Melanoma is the most aggressive type of skin cancer, which readily metastasizes through lymph nodes to the lungs, liver, and brain. Since the repeated administration of most chemotherapeutic drugs develops chemoresistance and severe systemic toxicities, herein we synthesized 2-(4-hydroxy-1H-indol-3-yl)-1H-imidazol-4-yl)(3,4,5-trimethoxyphenyl) methanone (abbreviated as QW-296), a novel tubulin destabilizing agent with little susceptible to transporter-mediated drug resistance. QW-296 disturbed the microtubule dynamics at the nanomolar concentration in A375 and B16F10 melanoma cells. QW-296 binding to colchicine-binding site on tubulin protein was confirmed by molecular modeling and tubulin polymerization assay. QW-296 significantly inhibited A375 and B16F10 cell proliferation, induced G2/M cell cycle arrest and led to apoptosis and cell death. To improve its aqueous solubility, QW-296 was encapsulated into methoxy poly(ethyleneglycol)-b-poly(carbonate-co-lactide) [mPEG-b-P(CB-co-LA)] polymeric nanoparticles by solvent evaporation, with the mean particle size of 122.0 ±â€¯2.28 nm and drug loading of 3.70% (w/w). Systemic administration of QW-296 loaded nanoparticles into C57/BL6 albino mice bearing lung metastatic melanoma at the dose of 20 mg/kg 4 times a week for 1.5 weeks resulted in significant tumor regression and prolonged mouse median survival without significant change in mouse body weight. In conclusion, QW-296 loaded nanoparticles have the potential to treat metastatic melanoma.

Recent advances in selective alpha1-adrenoreceptor antagonists as antihypertensive agents.

Hypertension is one of the most serious health problems of the modern world with a continuous rise in the number of patients. Selective alpha(1)-adrenoreceptor antagonists though have many advantages and uses in the management of arterial hypertension, their lack of specificity at the level of alpha(1)-adr subtypes leads to multiple side effects. Existence of multiple alpha(1)-adr subtypes holds great promise for the discovery and development of more specific and selective drug molecules, targeting only one alpha(1)-adr subtype at a time and thus relative freedom from side effects. Herein, the research done on the discovery and evaluation of a variety of chemically diverse structures as selective antagonists of alpha(1)-adr and alpha(1)-adr subtypes in recent years has been reviewed.

1,5-Benzothiazepine, a versatile pharmacophore: a review.

1,5-Benzothiazepine and 1,5-benzodiazipine are the two main seven-membered heterocyclic ring systems reported for their cardiac and psychotherapeutic activities. Successful introduction of diltiazem and clentiazem for angina pectoris, hypertension, arrhythmias and other related cardiac disorders proved potential of 1,5-benzothiazepine moiety. Subsequently 1,5-benzodiazepines were highlighted as important biologically active scaffolds. Also, discovery of thiazesim and quetiapine fumarate as psychotropic agents attracted much attention worldwide. The current review article focuses on pharmacological profile associated with 1,5-benzodiazepines. This article mainly covers structural modifications done for various targets along with the brief description of the targets.

Post-Ugi Cyclization for the Construction of Diverse Heterocyclic Compounds: Recent Updates.

Multicomponent reactions (MCRs) have proved as a valuable tool for organic and medicinal chemist because of their ability to introduce a large degree of chemical diversity in the product in a single step and with high atom economy. One of the dominant MCRs is the Ugi reaction, which involves the condensation of an aldehyde (or ketone), an amine, an isonitrile, and a carboxylic acid to afford an α-acylamino carboxamide adduct. The desired Ugi-adducts may be constructed by careful selection of the building blocks, opening the door for desired post-Ugi modifications. In recent times, the post-Ugi transformation has proved an important synthetic protocol to provide a variety of heterocyclic compounds with diverse biological properties. In this review, we have discussed the significant advancements reported in the recent literature with the emphasis to highlight the concepts and synthetic applications of the derived products along with critical mechanistic aspects.

New 2-Imino-2H-Chromene-3(N-aryl)carboxamides as Potential Cytotoxic Agents.

Synthesis and structure activity relationships of four series of novel 2-imino-2H-chromene-3(N-aryl) carboxamides (V-VIII) have been described by bioisosteric replacement of usually present ketone at 2nd position of coumarin with imine. Various substitutents are introduced on aryl and chromene ring of iminocoumarin to investigate the effect of lipophilicity and electronic properties of substituents on cytotoxic activity against four human cancer cell lines. Novel 2-imino-2H-chromene-3(N-aryl)carboxamides (V-VIII) were synthesized by the reaction of substituted 2- cyanoacetamides with different salicyaldehydes in the presence of sodium acetate in glacial acetic acid. Compound VIa showed potent activity against MCF-7 (IC50 = 8.5 µM), PC-3 (IC50 = 35.0 µM), A-549 (IC50 = 0.9 µM) and Caco-2 (IC50 = 9.9 µM) cell lines. The anticancer results revealed that most of the synthesized compounds showed equipotent activity with the standard 5-fluorouracil and docetaxel on Caco-2 and MCF-7 cell lines, respectively.

Design and Green Synthesis of Thieno[2,3-d]pyrimidine Analogues as Potential Antiproliferative Agents.

BACKGROUND: Despite of significant progress achieved in the chemotherapy of cancer; it is still among the leading cause of morbidity and mortality worldwide. OBJECTIVE: Taking cognizance of the extensive biological potential of reported thieno[2,3-d]pyrimidines and inspired by the clinically available anticancer agents dasatinib and gefitinib, 4-substituted thieno[2,3-d]pyrimidines have been synthesized. METHODS: The compounds were synthesized via microwave-assisted methods and screened for their cytotoxic activity against liver HepG-2, lung NCI-H522, melanoma A-375, pancreatic MIA PaCa-2 and colon CaCo-2 human cancer cell lines using MTT assay. RESULTS: The antiproliferative potential of most active compounds 20b and 20f (piperidino substituted); and 22d (hybrid analogue of Dasatinib) was further assessed and confirmed by calcein AM and colony formation assay, which revealed the higher potency of hybrid analogue 22d in comparison to piperidino substituted derivative 20f. CONCLUSION: Flow cytometer based cell cycle perturbation experiments revealed that antiproliferative effects of the most active compound 22d was associated with increased proportion of cells in the G2/M and subG0/G1 phases of the cell cycle. In silico ADME studies also confer the drug like characteristics of the potent compounds.

4-Substituted thieno[2,3-d]pyrimidines as potent antibacterial agents: Rational design, microwave-assisted synthesis, biological evaluation and molecular docking studies.

In an attempt to discover a new class of antibacterial agents with improved efficacy and to overcome the drug-resistant problems, some novel 4-substituted thieno[2,3-d]pyrimidines have been synthesized via microwave-assisted methodology and evaluated for their in vitro antibacterial activity against various pathogenic bacterial strains. Compounds 12b and 13c showed the promising inhibitory potencies against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli with MICs ranging from 2 to 10 µg/ml. Compound 13c was also found to be highly potent against methicillin-resistant S. aureus (MRSA) with MIC value of 4 µg/ml. Docking simulation studies have been performed to unravel the mode of action and association study indicate the binding of potent compounds with DHPS enzyme. In silico ADME studies suggest the drug-like characteristics of the potent compounds.