An assessment of crucial structural contributors of HDAC6 inhibitors through fragment-based non-linear pattern recognition and molecular dynamics simulation approaches

Amidst the Zn2+-dependant isoforms of the HDAC family, HDAC6 has emerged as a potential target associated with an array of diseases, especially cancer and neuronal disorders like Rett's Syndrome, Alzheimer's disease, Huntington's disease, etc. Also, despite the availability of a handful of HDAC inhibitors in the market, their non-selective nature has restricted their use in different disease conditions. In this situation, the development of selective and potent HDAC6 inhibitors will provide efficacious therapeutic agents to treat different diseases. In this context, this study has been carried out to evaluate the potential structural contributors of quinazoline-cap-containing HDAC6 inhibitors via machine learning (ML), conventional classification-dependant QSAR, and MD simulation-based binding mode of interaction analysis toward HDAC6 binding. This combined conventional and modern molecular modeling study has revealed the significance of the quinazoline moiety, substitutions present at the quinazoline cap group, as well as the importance of molecular property, number of hydrogen bond donor-acceptor functions, carbon-chlorine distance that significantly affects the HDAC6 binding of these inhibitors, subsequently affecting their potency . Interestingly, the study also revealed that the substitutions such as the chloroethyl group, and bulky quinazolinyl cap group can affect the binding of the cap function with the amino acid residues present in the loops proximal to the catalytic site of HDAC6. Such contributions of cap groups can lead to both stabilization and destabilization of the cap function after occupying the hydrophobic catalytic site by the aryl hydroxamate linker-ZBG functions.

Exploring different classification-dependent QSAR modelling strategies for HDAC3 inhibitors in search of meaningful structural contributors

Histone deacetylase 3 (HDAC3), a Zn2+-dependent class I HDACs, contributes to numerous disorders such as neurodegenerative disorders, diabetes, cardiovascular disease, kidney disease and several types of cancers. Therefore, the development of novel and selective HDAC3 inhibitors might be promising to combat such diseases. Here, different classification-based molecular modelling studies such as Bayesian classification, recursive partitioning (RP), SARpy and linear discriminant analysis (LDA) were conducted on a set of HDAC3 inhibitors to pinpoint essential structural requirements contributing to HDAC3 inhibition followed by molecular docking study and molecular dynamics (MD) simulation analyses. The current study revealed the importance of hydroxamate function for Zn2+ chelation as well as hydrogen bonding interaction with Tyr298 residue. The importance of hydroxamate function for higher HDAC3 inhibition was noticed in the case of Bayesian classification, recursive partitioning and SARpy models. Also, the importance of substituted thiazole ring was revealed, whereas the presence of linear alkyl groups with carboxylic acid function, any type of ester function, benzodiazepine moiety and methoxy group in the molecular structure can be detrimental to HDAC3 inhibition. Therefore, this study can aid in the design and discovery of effective novel HDAC3 inhibitors in the future.

F127/chlorin e6-nanomicelles to enhance Ce6 solubility and PDT-efficacy mitigating lung metastasis in melanoma

Photodynamic Therapy (PDT) is a promising paradigm for treating cancer, especially superficial cancers, including skin and oral cancers. However, the effectiveness of PDT is hindered by the hydrophobicity of photosensitizers. Here, chlorin e6 (Ce6), a hydrophobic photosensitizer, was loaded into pluronic F127 micelles to enhance solubility and improve tumor-specific targeting efficiency. The resulting Ce6@F127 Ms demonstrated a significant increase in solubility and singlet oxygen generation (SOG) efficiency in aqueous media compared to free Ce6. The confocal imaging and fluorescence-activated cell sorting (FACS) analysis confirmed the enhanced internalization rate of Ce6@F127 Ms in murine melanoma cell lines (B16F10) and human oral carcinoma cell lines (FaDu). Upon laser irradiation (666 nm), the cellular phototoxicity of Ce6@F127 Ms against B16F10 and FaDu was approximately three times higher than the free Ce6 treatment. The in vivo therapeutic investigations conducted on a murine model of skin cancer demonstrated the ability of Ce6@F127 Ms, when combined with laser treatment, to penetrate solid tumors effectively, which resulted in a significant reduction in tumor volume compared to free Ce6. Further, the Ce6@F127 Ms demonstrated upregulation of TUNEL-positive cells, downregulation of proliferation markers in tumor tissues, and prevention of lung metastasis with insignificant levels of proliferating cells and collagenase, as validated through immunohistochemistry. Subsequent analysis of serum and blood components affirmed the safety and efficacy of Ce6@F127 Ms in mice. Consequently, the developed Ce6@F127 Ms exhibits significant potential for concurrently treating solid tumors and preventing metastasis. The photodynamic formulation holds great clinical translation potential for treating superficial tumors.

Pharmacological blockade of HDAC6 attenuates cancer progression by inhibiting IL-1β and modulating immunosuppressive response in OSCC

Interleukin-1-beta (IL-1β) one of the biomarkers for oral squamous cell carcinoma (OSCC), is upregulated in tumor-microenvironment (TME) and associated with poor patient survival. Thus, a novel modulator of IL-1β would be of great therapeutic value for OSCC treatment. Here we report regulation of IL-1β and TME by histone deacetylase-6 (HDAC6)-inhibitor in OSCC. We observed significant upregulation of HDAC6 in 4-nitroquniline (4-NQO)-induced OSCC in mice and 4-NQO & Lipopolysaccharide (LPS) stimulated OSCC and fibroblast cells. Tubastatin A (TSA)-attenuated the OSCC progression in mice as observed improvement in the histology over tongue and esophagus, with reduced tumor burden. TSA treatment to 4-NQO mice attenuated protein expression of HDAC6, pro-and-mature-IL-1β and pro-and-cleaved-caspase-1 and ameliorated acetylated-tubulin. In support of our experimental work, human TCGA analysis revealed HDAC6 and IL-1β were upregulated in the primary tumor, with different tumor stages and grades. We found TSA modulate TME, indicated by downregulation of CD11b+Gr1+-Myeloid-derived suppressor cells, CD11b+F4/80+CD206+ M2-macrophages and increase in CD11b+F4/80+MHCII+ M1-macrophages. TSA significantly reduced the gene expression of HDAC6, IL-1β, Arginase-1 and iNOS in isolated splenic-MDSCs. FaDu-HTB-43 and NIH3T3 cells stimulated with LPS and 4-NQO exhibit higher IL-1β levels in the supernatant. Interestingly, immunoblot analysis of the cell lysate, we observed that TSA does not alter the expression as well as activation of IL-1β and caspase-1 but the acetylated-tubulin was found to be increased. Nocodazole pre-treatment proved that TSA inhibited the lysosomal exocytosis of IL-1β through tubulin acetylation. In conclusion, HDAC6 inhibitors attenuated TME and cancer progression through the regulation of IL-1β in OSCC.

Small-molecule-induced epigenetic rejuvenation promotes SREBP condensation and overcomes barriers to CNS myelin regeneration

Remyelination failure in diseases like multiple sclerosis (MS) was thought to involve suppressed maturation of oligodendrocyte precursors; however, oligodendrocytes are present in MS lesions yet lack myelin production. We found that oligodendrocytes in the lesions are epigenetically silenced. Developing a transgenic reporter labeling differentiated oligodendrocytes for phenotypic screening, we identified a small-molecule epigenetic-silencing-inhibitor (ESI1) that enhances myelin production and ensheathment. ESI1 promotes remyelination in animal models of demyelination and enables de novo myelinogenesis on regenerated CNS axons. ESI1 treatment lengthened myelin sheaths in human iPSC-derived organoids and augmented (re)myelination in aged mice while reversing age-related cognitive decline. Multi-omics revealed that ESI1 induces an active chromatin landscape that activates myelinogenic pathways and reprograms metabolism. Notably, ESI1 triggered nuclear condensate formation of master lipid-metabolic regulators SREBP1/2, concentrating transcriptional co-activators to drive lipid/cholesterol biosynthesis. Our study highlights the potential of targeting epigenetic silencing to enable CNS myelin regeneration in demyelinating diseases and aging.

Fragment-based discovery of new potential DNMT1 inhibitors integrating multiple pharmacophore modeling, 3D-QSAR, virtual screening, molecular docking, ADME, and molecular dynamics simulation approaches

DNA methyl transferases (DNMTs) are one of the crucial epigenetic modulators associated with a wide variety of cancer conditions. Among the DNMT isoforms, DNMT1 is correlated with bladder, pancreatic, and breast cancer, as well as acute myeloid leukemia and esophagus squamous cell carcinoma. Therefore, the inhibition of DNMT1 could be an attractive target for combating cancers and other metabolic disorders. The disadvantages of the existing nucleoside and non-nucleoside DNMT1 inhibitors are the main motive for the discovery of novel promising inhibitors. Here, pharmacophore modeling, 3D-QSAR, and e-pharmacophore modeling of DNMT1 inhibitors were performed for the large fragment database screening. The resulting fragments with high dock scores were combined into molecules. The current study revealed several constitutional pharmacophoric features that can be essential for selective DNMT1 inhibition. The fragment docking and virtual screening identified 10 final hit molecules that exhibited good binding affinities in terms of docking score, binding free energies, and acceptable ADME properties. Also, the modified lead molecules (GL1b and GL2b) designed in this study showed effective binding with DNMT1 confirmed by their docking scores, binding free energies, 3D-QSAR predicted activities and acceptable drug-like properties. The MD simulation studies also suggested that leads (GL1b and GL2b) formed stable complexes with DNMT1. Therefore, the findings of this study can provide effective information for the development/identification of novel DNMT1 inhibitors as effective anticancer agents.

Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

Chitosan oligosaccharide/pluronic F127 micelles exhibiting anti-biofilm effect to treat bacterial keratitis

Mono or dual chitosan oligosaccharide lactate (COL)-conjugated pluronic F127 polymers, FCOL1 and FCOL2 were prepared, self-assembled to form micelles, and loaded with gatifloxacin. The Gati@FCOL1/Gati@FCOL2 micelles preparation process was optimized by QbD analysis. Micelles were characterized thoroughly for size, CMC, drug compatibility, and viscosity by GPC, DLS, SEM, IR, DSC, and XRD. The micelles exhibited good cellular uptake in both monolayers and spheroids of HCEC. The antibacterial and anti-biofilm activities of the micelles were evaluated on P. aeruginosa and S. aureus. The anti-quorum sensing activity was explored in P. aeruginosa by analyzing micelles' ability to produce virulence factors, including AHLs, pyocyanin, and the motility behavior of the organism. Gati@FCOL2 Ms was mucoadhesive, cornea-penetrant, antibacterial, and inhibited the biofilm formation by P. aeruginosa and S. aureus significantly more than Gati@FCOL1. A significant reduction in bacterial load in mice cornea was observed after Gati@FCOL2 Ms-treatment to the P. aeruginosa-induced bacterial keratitis-infected mice.

Cationized gelatin-sodium alginate polyelectrolyte nanoparticles encapsulating moxifloxacin as an eye drop to treat bacterial keratitis

A mucoadhesive polyelectrolyte complex (PEC) nanoparticles were developed for ocular moxifloxacin (Mox) delivery in Bacterial Keratitis (BK). Moxifloxacin-loaded G/CG-Alg NPs were prepared by an amalgamation of cationic polymers (gelatin (G)/cationized gelatin (CG)), and anionic polymer (sodium alginate (Alg)) along with Mox respectively. Mox@CG-Alg NPs were characterized for physicochemical parameters such as particle size (DLS technique), morphology (SEM analysis), DSC, XRD, encapsulation efficiency, drug loading, mucoadhesive study (by texture analyzer), mucin turbidity, and viscosity assessment. The NPs uptake and toxicity of the formulation were analyzed in the Human Corneal Epithelial (HCE) cell line and an ocular irritation study was performed on the HET-CAM. The results indicated that the CG-Alg NPs, with optimal size (217.2 ± 4 nm) and polydispersity (0.22 ± 0.05), have shown high cellular uptake in monolayer and spheroids of HCE. The drug-loaded formulation displayed mucoadhesiveness, trans-corneal permeation, and sustained the release of the Mox. The anti-bacterial efficacy studied on planktonic bacteria/biofilms of P. aeruginosa and S. aureus (in vitro) indicated that the Mox@CG-Alg NPs displayed low MIC, higher zone of bacterial growth inhibition, and cell death compared to free Mox. A significant reduction of bacterial load was observed in the BK-induced mouse model.

3D-Printed Inherently Antibacterial Contact Lens-Like Patches Carrying Antimicrobial Peptide Payload for Treating Bacterial Keratitis

Delivery of therapeutic agents through contact lenses-like patches is a promising strategy to achieve significant bioavailability with negligible eye drainage. The present study investigates the preparation and 3D printing of mucoadhesive gelatin methacryloyl (GelMA)/chitosan methacryloyl (ChiMA) hydrogels to fabricate them as contact lens-like patches (CLP) loaded with antimicrobial peptide, S100A12 (AMP) for treating bacterial keratitis (BK). Extrusion technology is used to print the patches layer by layer to form a hemispherical scaffold suitable for eyewear, and 3D-printed CLP is crosslinked using Irgacure 2959 under UV light. The results from the in vivo experiment conducted on Pseudomonas aeruginosa-infected BK rabbit model after the treatment with AMP-loaded CLP have shown a significant decrease in bacterial load when plated for CFU. The newly developed delivery system containing AMP has great potential to overcome the treatment challenges of multidrug resistance (MDR) in bacteria and eliminate the frequent dosing associated with eye drops. The presence of chitosan in the formulation provides a synergetic effect on the AMP in disrupting bacterial biofilms. The ease of using 3D printing will open new avenues for optimizing the dosage depending on the severity of the BK in the patients, which can be used as personalized medicine.

Significance of TRAIL/Apo-2 ligand and its death receptors in apoptosis and necroptosis signalling: Implications for cancer-targeted therapeutics

The human immune defensesystem routinely expresses the tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), which is the most prevalent element for antitumor immunity. TRAIL associates with its death receptors (DRs), DR4 (TRAIL-R1), and DR5 (TRAIL-R2), in cancer cells to initiate the intracellular apoptosis cascade. Accordingly, numerous academic institutions and pharmaceutical companies havetried to exploreTRAIL's capacity to kill tumourcells by producing recombinant versions of it (rhTRAIL) or TRAIL receptor agonists (TRAs) [monoclonal antibody (mAb), synthetic and natural compounds, etc.] and molecules that sensitize TRAIL signalling pathway for therapeutic applications. Recently, several microRNAs (miRs) have been found to activate or inhibit death receptor signalling. Therefore, pharmacological regulation of these miRs may activate or resensitize the TRAIL DRs signal, and this is a novel approach for developing anticancer therapeutics. In this article, we will discuss TRAIL and its receptors and molecular pathways by which it induces various cell death events. We will unravel potential innovative applications of TRAIL-based therapeutics, and other investigated therapeutics targeting TRAIL-DRs and summarize the current preclinical pharmacological studies and clinical trials. Moreover, we will also emphasizea few situations where future efforts may be addressed to modulate the TRAIL signalling pathway.

Discovery of thiazolidinedione-based pancreatic lipase inhibitors as anti-obesity agents: synthesis, in silico studies and pharmacological investigations

A series of new 2,5-disubstituted arylidene derivatives of thiazolidinedione (16a-e, 17a-d, 18a-c) designed using molecular hybridization approach were synthesized, structurally characterized, and explored for their anti-obesity potential via inhibition of Pancreatic Lipase (PL). Compound 18a presented the most potent PL inhibitory activity with IC50 = 2.71 ± 0.31 µM, as compared to the standard drug, Orlistat (IC50 = 0.99 µM). Kinetic study revealed reversible competitive mode of enzyme inhibition by compound 18a with an inhibitory constant value of 1.19 µM. The most promising compound 18a revealed satisfactory binding mode within the active site of the target protein (human PL, PDB ID: 1LPB). Also, MM/PBSA binding free energy and molecular dynamics (MD) simulation analysis were performed for the most promising compound 18a, which showed potent inhibition according to the results of in vitro studies. Furthermore, a stable conformation of the 1LPB-ligand suggested the stability of this compound in the dynamic environment. The ADME and toxicity analysis of the compounds were examined using web-based online platforms. Results of in vivo studies confirmed the anti-obesity efficacy of compound 18a, wherein oral treatment with compound 18a (30 mg/kg) resulted in a significant reduction in the body weight, BMI, Lee index, feed intake (in Kcal), body fat depots and serum triglycerides. Compound 18a significantly decreased the levels of serum total cholesterol (TC) to 128.6 ± 0.59 mg/dl and serum total triglycerides (TG) to 95.73 ± 0.67 mg/dl as compared to the HFD control group. The present study identified disubstituted TZD derivatives as a new promising class of anti-obesity agents.Communicated by Ramaswamy H. Sarma.

Exploring crucial structural attributes of quinolinyl methoxyphenyl sulphonyl-based hydroxamate derivatives as ADAM17 inhibitors through classification-dependent molecular modelling approaches

A Disintegrin and Metalloproteinase 17 (ADAM17), a Zn2+-dependent metalloenzyme of the adamalysin family of the metzincin superfamily, is associated with various pathophysiological conditions including rheumatoid arthritis and cancer. However, no specific inhibitors have been marketed yet for ADAM17-related disorders. In this study, 94 quinolinyl methoxyphenyl sulphonyl-based hydroxamates as ADAM17 inhibitors were subjected to classification-based molecular modelling and binding pattern analysis to identify the significant structural attributes contributing to ADAM17 inhibition. The statistically validated classification-based models identified the importance of the P1' substituents such as the quinolinyl methoxyphenyl sulphonyl group of these compounds for occupying the S1' - S3' pocket of the enzyme. The quinolinyl function of these compounds was found to explore stable binding of the P1' substituents at the S1' - S3' pocket whereas the importance of the sulphonyl and the orientation of the P1' moiety also revealed stable binding. Based on the outcomes of the current study, four novel compounds of different classes were designed as promising ADAM17 inhibitors. These findings regarding the crucial structural aspects and binding patterns of ADAM17 inhibitors will aid the design and discovery of novel and effective ADAM17 inhibitors for therapeutic advancements of related diseases.

A combined ligand-based and structure-based in silico molecular modeling approach to pinpoint the key structural attributes of hydroxamate derivatives as promising meprin β inhibitors

Human meprin β is a Zn2+-containing multidomain metalloprotease enzyme that belongs to the astacin family of the metzincin endopeptidase superfamily. Meprin β, with its diverse tissue expression pattern and wide substrate specificity, plays a significant role in various biological processes, including regulation of IL-6R pathways, lung fibrosis, collagen deposition, cellular migration, neurotoxic amyloid β levels, and inflammation. Again, meprin β is involved in Alzheimer's disease, hyperkeratosis, glomerulonephritis, diabetic kidney injury, inflammatory bowel disease, and cancer. Despite a crucial role in diverse disease processes, no such promising inhibitors of meprin β are marketed to date. Thus, it is an unmet requirement to find novel promising meprin β inhibitors that hold promise as potential therapeutics. In this study, a series of arylsulfonamide and tertiary amine-based hydroxamate derivatives as meprin β inhibitors has been analyzed through ligand-based and structure-based in silico approaches to pinpoint their structural and physiochemical requirements crucial for exerting higher inhibitory potential. This study identified different crucial structural features such as arylcarboxylic acid, sulfonamide, and arylsulfonamide moieties, as well as hydrogen bond donor and hydrophobicity, inevitable for exerting higher meprin β inhibition, providing valuable insight for their further future development.Communicated by Ramaswamy H. Sarma.

Fragment-based investigation of thiourea derivatives as VEGFR-2 inhibitors: a cross-validated approach of ligand-based and structure-based molecular modeling studies

Angiogenesis is mediated by the vascular endothelial growth factor (VEGF) that plays a key role in the modulation of progression, invasion and metastasis, related to solid tumors and hematological malignancies. Several small-molecule VEGFR-2 inhibitors are marketed, but their usage is restricted to specific cancers due to severe toxicities. Therefore, cost-effective novel small molecule VEGFR-2 inhibitors may be an alternative to overcome these adverse effects. Here, a set of thiourea-based VEGFR-2 inhibitors were considered for a combined fragment-based QSAR technique, structure-based molecular docking followed by molecular dynamics simulation studies to acquire insights into the key structural attributes and the binding pattern of enzyme-ligand interactions. Noticeably, amine-substituted quinazoline phenyl ring and a higher number of nitrogen atoms, and the hydrazide function in the molecular structure are crucial for VEGFR-2 inhibition whereas methoxy groups are detrimental to VEGFR-2 inhibition. The MD simulation study of sorafenib and thiourea derivatives explored the significance of urea and thiourea moiety binding at VEGFR-2 active site that can be utilized further in the future to design molecules for greater binding stability and better VEGFR-2 selectivity. Therefore, such findings can be beneficial for the development of newer VEGFR-2 inhibitors for further refinement to acquire better therapeutic efficacy.Communicated by Ramaswamy H. Sarma.

Human Serum Albumin-Oxaliplatin (Pt(IV)) prodrug nanoparticles with dual reduction sensitivity as effective nanomedicine for triple-negative breast cancer

Nanomedicines have emerged as a potential strategy to reduce the toxic effect of drugs administered via conventional approaches. Nanomedicines undergo passive and active targeting of the tumor tissues, thereby causing localized drug delivery and reducing drug demand and side effects. Here, we prepared reduction-sensitive oxaliplatin-conjugated human serum albumin nanoparticles with a small size, uniform surfaces, and a satisfactory encapsulation coefficient. The findings of cellular studies demonstrate that utilizing human serum albumin is effective for active tumor targeting. The presence of glutathione-sensitive disulfide linkers in the crosslinking agent and between Pt(IV) and HSA provided dual reduction sensitivity. Cytotoxicity and cell death were enhanced compared to free Oxaliplatin. The outcomes demonstrate that the approach maximized Oxaliplatin's ability to control tumor growth, induced apoptosis, and reduced drug resistance. Therefore, for the first time, our results imply that OXA-SS-HSA NPs were biocompatible, smart, and effective anticancer nanomedicine for triple-negative breast cancer therapy.

A fragment-based exploration of diverse MMP-9 inhibitors through classification-dependent structural assessment

Matrix metalloproteinases (MMPs) are belonging to the Zn2+-dependent metalloenzymes. These can degenerate the extracellular matrix (ECM) that is entailed with various biological processes. Among the MMP family members, MMP-9 is associated with several pathophysiological circumstances. Apart from wound healing, remodeling of bone, inflammatory mechanisms, and rheumatoid arthritis, MMP-9 has also significant roles in tumor invasion and metastasis. Therefore, MMP-9 has been in the spotlight of anticancer drug discovery programs for more than a decade. In this present study, classification-based QSAR techniques along with fragment-based data mining have been carried out on divergent MMP-9 inhibitors to point out the important structural attributes. This current study may be able to elucidate the importance of several pivotal molecular fragments such as sulfonamide, hydroxamate, i-butyl, and ethoxy functions for imparting potential MMP-9 inhibition. These observations are in correlation with the ligand-bound co-crystal structures of MMP-9. Therefore, these findings are beneficial for the design and discovery of effective MMP-9 inhibitors in the future.

Advances in the Delivery and Development of Epigenetic Therapeutics for the Treatment of Cancer

Gene expression at the transcriptional level is altered by epigenetic modifications such as DNA methylation, histone methylation, and acetylation, which can upregulate, downregulate, or entirely silence genes. Pathological dysregulation of epigenetic processes can result in the development of cancer, neurological problems, metabolic disorders, and cardiovascular diseases. It is of promising therapeutic interest to find medications that target these epigenetic alterations. Despite the enormous amount of work that has been done in this area, very few molecules have been approved for clinical purposes. This article provides a comprehensive review of recent advances in epigenetic therapeutics for cancer, with a specific focus on emerging delivery and development strategies. Various delivery systems, including pro-drugs, conjugated molecules, nanoparticles (NPs), and liposomes, as well as remedial strategies such as combination therapies, and epigenetic editing, are being investigated to improve the efficacy and specificity of epigenetic drugs (epi-drugs). Furthermore, the challenges associated with available epi-drugs and the limitations of their translation into clinics have been discussed. Target selection, isoform selectivity, physiochemical properties of synthesized molecules, drug screening, and scalability of epi-drugs from preclinical to clinical fields are the major shortcomings that are addressed. This Review discusses novel strategies for the identification of new biomarkers, exploration of the medicinal chemistry of epigenetic modifiers, optimization of the dosage regimen, and design of proper clinical trials that will lead to better utilization of epigenetic modifiers over conventional therapies. The integration of these approaches holds great potential for improving the efficacy and precision of epigenetic treatments, ultimately benefiting cancer patients.

MiR-326-mediated overexpression of NFIB offsets TGF-β induced epithelial to mesenchymal transition and reverses lung fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a progressively fatal and incurable disease characterized by the loss of alveolar structures, increased epithelial-mesenchymal transition (EMT), and aberrant tissue repair. In this study, we investigated the role of Nuclear Factor I-B (NFIB), a transcription factor critical for lung development and maturation, in IPF. Using both human lung tissue samples from patients with IPF, and a mouse model of lung fibrosis induced by bleomycin, we showed that there was a significant reduction of NFIB both in the lungs of patients and mice with IPF. Furthermore, our in vitro experiments using cultured human lung cells demonstrated that the loss of NFIB was associated with the induction of EMT by transforming growth factor beta (TGF-β). Knockdown of NFIB promoted EMT, while overexpression of NFIB suppressed EMT and attenuated the severity of bleomycin-induced lung fibrosis in mice. Mechanistically, we identified post-translational regulation of NFIB by miR-326, a miRNA with anti-fibrotic effects that is diminished in IPF. Specifically, we showed that miR-326 stabilized and increased the expression of NFIB through its 3'UTR target sites for Human antigen R (HuR). Moreover, treatment of mice with either NFIB plasmid or miR-326 reversed airway collagen deposition and fibrosis. In conclusion, our study emphasizes the critical role of NFIB in lung development and maturation, and its reduction in IPF leading to EMT and loss of alveolar structures. Our study highlights the potential of miR-326 as a therapeutic intervention for IPF. The schema shows the role of NFIB in maintaining the normal epithelial cell characteristics in the lungs and how its reduction leads to a shift towards mesenchymal cell-like features and pulmonary fibrosis. A In normal lungs, NFIB is expressed abundantly in the epithelial cells, which helps in maintaining their shape, cell polarity and adhesion molecules. However, when the lungs are exposed to factors that induce pulmonary fibrosis, such as bleomycin, or TGF-β, the epithelial cells undergo epithelial to mesenchymal transition (EMT), which leads to a decrease in NFIB. B The mesenchymal cells that arise from EMT appear as spindle-shaped with loss of cell junctions, increased cell migration, loss of polarity and expression of markers associated with mesenchymal cells/fibroblasts. C We designed a therapeutic approach that involves exogenous administration of NFIB in the form of overexpression plasmid or microRNA-326. This therapeutic approach decreases the mesenchymal cell phenotype and restores the epithelial cell phenotype, thus preventing the development or progression of pulmonary fibrosis.

Pharmacophore-based virtual screening, 3D QSAR, Docking, ADMET, and MD simulation studies: An in silico perspective for the identification of new potential HDAC3 inhibitors

Histone deacetylase 3 (HDAC3) is an epigenetic regulator that involves gene expression, apoptosis, and cell cycle progression, and the overexpression of HDAC3 is accountable for several cancers, neurodegeneracy, and many other diseases. Therefore, HDAC3 emerged as a promising drug target for the novel drug design. Here, we carried out the pharmacophore modeling using 50 benzamide-based HDAC3 selective inhibitors and utilized it for PHASE ligand screening to retrieve the hits with similar pharmacophore features. The dataset inhibitors of best hypotheses used to build the 3D QSAR model and the generated 3D QSAR model resulted in good PLS statistics with a regression coefficient (R2) of 0.89, predictive coefficient (Q2) of 0.88, and Pearson-R factor of 0.94 indicating its excellent predictive ability. The hits retrieved from pharmacophore-based virtual screening were subjected to docking against HDAC3 for the identification of potential inhibitors. A total of 10 hitsM1 to M10 were ranked using their scoring functions and further subject to lead optimization. The Prime MM/GBSA, AutoDock binding free energies, and ADMET studies were implemented for the selection of lead candidates. The four ligand molecules M1, M2, M3, and M4 were identified as potential leads against HDAC3 after lead optimization. The top two leads M1 and M2 were subjected to MD simulations for their stability evaluation with HDAC3. The newly designed leads M11 and M12 were identified as HDAC3 potential inhibitors from MD simulations studies. Therefore, the outcomes of the present study could provide insights into the discovery of new potential HDAC3 inhibitors with improved selectivity and activity against a variety of cancers and neurodegenerative diseases.

Polymeric graphene oxide nanoparticles loaded with doxorubicin for combined photothermal and chemotherapy in triple negative breast cancer

Combining photothermal and chemotherapy is an emerging strategy for tumor irradiation in a minimally invasive manner, utilizing photothermal transduction agents and anticancer drugs. The present work developed a 2D carbon nanomaterial graphene oxide (GO)-based nanoplatform that converted to 3D colloidal spherical structures upon functionalization with an amphiphilic polymer mPEG-PLA (1, 0.5/1/2) and entrapped doxorubicin (Dox) physically. The Dox@GO(mPP) (1/0.5) NPs displayed the least particle size (161 nm), the highest stability with no aggregation, the highest Dox loading (6.3 %) and encapsulation efficiency (70 %). The therapeutic efficacy was determined in vitro and in vivo using murine (4 T1) and human triple-negative breast cancer cells (MDA-MB-231), and 4 T1-Luc-tumor bearing mouse models. The results demonstrated that the Dox@GO(mPP) (1/0.5) NPs treatment with laser (+L) (808 nm) was highly efficient in inducing apoptosis, cell cycle arrest (G2/M) phase, significant cytotoxicity, mitochondrial membrane depolarization, ROS generation, and photothermal effect leading to a higher proportion of cell death than free Dox, and Dox@GO(mPP) (1/0.5) NPs (-L). The anticancer studies in mice harboring the 4 T1-Luc tumor showed that combination of Dox@GO(mPP) (1/0.5) NPs (+L) effectively reduced tumor development and decreased lung metastasis. The developed nanoplatform could be a promising combination chemo-photothermal treatment option for triple-negative breast cancer.

Assessing structural insights into in-house arylsulfonyl L-(+) glutamine MMP-2 inhibitors as promising anticancer agents through structure-based computational modelling approaches

MMP-2 is potentially contributing to several cancer progressions including leukaemias. Therefore, considering MMP-2 as a promising target, novel anticancer compounds may be designed. Here, 32 in-house arylsulfonyl L-(+) glutamines were subjected to various structure-based computational modelling approaches to recognize crucial structural attributes along with the spatial orientation for higher MMP-2 inhibition. Again, the docking-based 2D-QSAR study revealed that the Coulomb energy conferred by Tyr142 and total interaction energy conferred by Ala84 was crucial for MMP-2 inhibition. Importantly, the docking-dependent CoMFA and CoMSIA study revealed the importance of favourable steric, electrostatic, and hydrophobic substituents at the terminal phenyl ring. The MD simulation study revealed a lower fluctuation in the RMSD, RMSF, and Rg values indicating stable binding interactions of MMP-2 and these molecules. Moreover, the residual hydrogen bond and their interaction analysis disclosed crucial amino acid residues responsible for forming potential hydrogen bonding for higher MMP-2 inhibition. The results can effectively aid in the design and discovery of promising small-molecule drug-like MMP-2 inhibitors with greater anticancer potential in the future.

Selective HDAC3 Inhibitors with Potent In Vivo Antitumor Efficacy against Triple-Negative Breast Cancer

HDAC3 modulation shows promise for breast cancer, including triple-negative cases. Novel pyrazino-hydrazide-based HDAC3 inhibitors were designed and synthesized. Lead compound 4i exhibited potent HDAC3 inhibition (IC50 = 14 nM) with at least 121-fold selectivity. It demonstrated strong cytotoxicity against triple-negative breast cancer cells (IC50: 0.55 μM for 4T1, 0.74 μM for MDA-MB-231) with least normal cell toxicity. Metabolically stable 4i displayed a superior pharmacokinetic profile. A dose-dependent therapeutic efficacy of 4i was observed in a tumor-bearing mouse model. The biomarker analysis with tumor tissues displayed enhanced acetylation on Ac-H3K9, Ac-H3K27, and Ac-H4K12 compared to Ac-tubulin and Ac-SMC3 indicating HDAC3 selectivity of 4i in vivo. The immunoblotting study with tumor tissue showed upregulation of apoptotic proteins caspase-3, caspase-7, and cytochrome c and the downregulation of proliferation markers Bcl-2, CD44, EGFR, and Ki-67. Compound 4i represents a promising candidate for targeted breast cancer therapy, particularly for cases with triple-negative breast cancer.

Fragment-based structural exploration and chemico-biological interaction study of HDAC3 inhibitors through non-linear pattern recognition, chemical space, and binding mode of interaction analysis

HDAC3 is an emerging target for the identification and discovery of novel drug candidates against several disease conditions including cancer. Here, a fragment-based non-linear machine learning (ML) method along with chemical space exploration followed by a structure-based binding mode of interaction analysis study was carried out on some HDAC3 inhibitors to obtain the key structural features modulating HDAC3 inhibition. Both the ML and chemical space analysis identified several physicochemical and structural properties namely lipophilicity, polar and relative polar surface area, arylcarboxamide moiety, bulky fused aromatic group, n-alkyl, and cinnamoyl moieties, the higher number of oxygen atoms, π-electrons for the substituted tetrahydrofuronaphthodioxolone moiety favorable for higher HDAC3 inhibition. Moreover, hydrogen bond forming capabilities, the length and substitution position of the linker moiety, the importance of phenyl ring in the linker motif, the contribution of heterocyclic cap moieties for effective inhibitor binding at the HDAC3 catalytic site that correspondingly affects the HDAC3 inhibitory potency. Again, macrocyclic ring structure and cyclohexyl cap moiety are responsible for lower HDAC3 inhibition. The MD simulation study of selected compounds explained strong binding patterns at the HDAC3 active site as evidenced by the lower RMSD and RMSF values. Nevertheless, it also explained the importance of the crucial structural fragments derived from the fragment-based analysis during ligand-enzyme interactions. Therefore, the outcomes of this current structural analysis will be a useful tool for fragment-based drug discovery of effective HDAC3 inhibitors for clinical therapeutics in the future.Communicated by Ramaswamy H. Sarma.

Employing comparative QSAR techniques for the recognition of dibenzofuran and dibenzothiophene derivatives toward MMP-12 inhibition

Among various matrix metalloproteinases (MMPs), MMP-12 is one of the potential targets for cancer and other diseases. However, none of the MMP-12 inhibitors has passed the clinical trials to date. Therefore, designing potential MMP-12 inhibitors as new drug molecules can provide effective therapeutic strategies for several diseases. In this study, a series of dibenzofuran and dibenzothiophene derivatives were subjected to different 2D and 3D-QSAR techniques to point out the crucial structural contributions highly influential toward the MMP-12 inhibitory activity. These techniques identified some structural attributes of these compounds that are responsible for influencing their MMP-12 inhibition. The carboxylic group may enhance proper binding with catalytic Zn²⁺ ion at the MMP-12 active site. Again, the i-propyl sulfonamido carboxylic acid function contributed positively toward MMP-12 inhibition. Moreover, the dibenzofuran moiety conferred stable binding at the S1' pocket for higher MMP-12 inhibition. The steric and hydrophobic groups were found favourable near the furan ring substituted at the dibenzofuran moiety. Besides these ligand-based approaches, molecular docking and molecular dynamic (MD) simulation studies not only elucidated the importance of several aspects of these MMP-12 inhibitors while disclosing the significance of the finding of these QSAR studies and their influences toward MMP-12 inhibition. The MD simulation study also revealed stable and compact binding between such compounds at the MMP-12 active site. Therefore, the findings of these validated ligand-based and structure-based molecular modeling studies can aid the development of selective and potent lead molecules that can be used for the treatment of MMP-12-associated diseases.Communicated by Ramaswamy H. Sarma.

Chitosan-poly(lactide-co-glycolide)/poloxamer mixed micelles as a mucoadhesive thermo-responsive moxifloxacin eye drop to improve treatment efficacy in bacterial keratitis

A mucoadhesive self-assembling polymeric system was developed to carry moxifloxacin (M) for treating bacterial keratitis (BK). Chitosan-PLGA (C) conjugate was synthesized, and poloxamers (F68/127) were mixed in different proportions (1: 5/10) to prepare moxifloxacin (M)-encapsulated mixed micelles (M@CF68/127(5/10)Ms), including M@CF68(5)Ms, M@CF68(10)Ms, M@CF127(5)Ms, and M@CF127(10)Ms. The corneal penetration and mucoadhesiveness were determined biochemically, in vitro using human corneal epithelial (HCE) cells in monolayers and spheroids, ex vivo using goat cornea, and in vivo via live-animal imaging. The antibacterial efficacy was studied on planktonic biofilms of P. aeruginosa and S. aureus (in vitro) and Bk-induced mice (in vivo). Both M@CF68(10)Ms and M@CF127(10)Ms demonstrated high cellular uptake, corneal retention, muco-adhesiveness, and antibacterial effect, with M@CF127(10)Ms exhibiting superior therapeutic effects in P. aeruginosa and S. aureus-infected BK mouse model by reducing the corneal bacterial load and preventing corneal damage. Therefore, the newly developed nanomedicine is promising for clinical translation in treating BK.

The quality by design approach for optimization of slayer exciter based low power portable atmospheric plasma jet on bactericidal efficacy of Pseudomonas aeruginosa

A simple, portable, economical low-temperature atmospheric plasma (LTAP) for bactericidal efficacy of Gram-negative bacteria (Pseudomonas aeruginosa) with different carrier gases (argon, helium, and nitrogen) using the quality by design (QbD) approach, design of experiments (DoE), and response surface graphs (RSG) is presented. Box-Behnken design was used as the DoE to narrow down and further optimize the experimental factors of LTAP. Plasma exposure time, input DC voltage, and carrier gas flow rate were varied to examine the bactericidal efficacy using the zone of inhibition (ZOI). A higher bactericidal efficacy was achieved under the optimal bactericidal factors having ZOI of 50.837 ± 2.418 mm² with the plasma power density of 132 mW/cm³ for LTAP-Ar at 61.19 s, 14.8747 V, and 219.379 sccm than LTAP-He and LTAP-N₂ . The LTAP-Ar was further evaluated at different frequencies and probe lengths to achieve a ZOI of 58.237 ± 4.01 mm² .

Exploration of structural alerts and fingerprints for novel anticancer therapeutics: a robust classification-QSAR dependent structural analysis of drug-like MMP-9 inhibitors

Among various matrix metalloproteinases (MMPs), overexpression of MMP9 has been established as a key player in a variety of cancers. Therefore, MMP9 has emerged as a promising biomolecule that may be targeted to design potent inhibitors as novel anticancer therapeutics. In this study, a large database containing 1,123 drug-like MMP-9 inhibitors was considered for robust classification-dependent fragment-based QSAR study through SARpy, Bayesian classification, and recursive partitioning analyses and were validated by both internal and external validation techniques. In a nutshell, all these classification-dependent techniques revealed some common structural alerts and sub-structural fingerprints responsible for modulating MMP-9 inhibition. These observations are in agreement with the interactions obtained from the ligand-bound co-crystal structures of MMP-9 justifying the robustness of the current study. Finally, based on these crucial structural fragments, some new lead compounds were designed and further validated by the binding mode of interaction analysis. Therefore, these findings may be beneficial in designing novel and potential MMP-9 inhibitors in the future as a weapon to combat several cancers.

Evaluation of Potential Neuroprotective Effects of Vanillin Against MPP+/MPTP-Induced Dysregulation of Dopaminergic Regulatory Mechanisms in SH-SY5Y Cells and a Mouse Model of Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative condition. The pathogenesis of PD is still unknown, and drugs available for PD treatment either have side effects or have suboptimal efficacy. Flavonoids are potent antioxidants having little toxicity with extended use, suggesting they might hold promising therapeutic potential against PD. Vanillin (Van) is a phenolic compound that has exhibited neuroprotective properties in various neurological disorders, including PD. However, the neuroprotective role of Van in PD and its underlying mechanisms are scarce and therefore need more exploration. Here, we evaluated the neuroprotective potential of Van and its associated mechanisms against MPP⁺/MPTP-induced neuronal loss in differentiated human neuroblastoma (SH-SY5Y) cells and the mouse model of PD. In the present study, Van treatment significantly enhanced the cell viability and alleviated oxidative stress, mitochondrial membrane potential, and apoptosis in MPP⁺-intoxicated SH-SY5Y cells. Moreover, Van significantly ameliorated the MPP⁺-induced dysregulations in protein expression of tyrosine hydroxylase (TH) and mRNA expressions of GSK-3β, PARP1, p53, Bcl-2, Bax, and Caspase-3 genes in SH-SY5Y cells. Similar to our in vitro results, Van significantly alleviated MPTP-induced neurobehavioral dysregulations, oxidative stress, aberrant TH protein expressions, and immunoreactivity in SNpc of mice brains. Treatment of Van also prevented MPTP-mediated loss of TH-positive intrinsic dopaminergic neurons to SNpc and TH-fibers projecting to the striatum of mice. Thus, Van exhibited promising neuroprotective properties in the current study against MPP⁺/MPTP-intoxicated SH-SY5Y cells and mice, indicating its potential therapeutic properties against PD pathology.

HDAC8 as an emerging target in drug discovery with special emphasis on medicinal chemistry

HDAC8 catalyzes the deacetylation of both histones and nonhistone proteins. The abnormal expression of HDAC8 is associated with various pathological conditions causing cancer and other diseases like myopathies, Cornelia de Lange syndrome, renal fibrosis, and viral and parasitic infections. The substrates of HDAC8 are involved in diverse molecular mechanisms of cancer such as cell proliferation, invasion, metastasis and drug resistance. Based on the crystal structures and the key residues at the active site, HDAC8 inhibitors have been designed along the canonical pharmacophore. This article details the importance, recent advancements, and the structural and functional aspects of HDAC8 with special emphasis on the medicinal chemistry aspect of HDAC8 inhibitors that will help in developing novel epigenetic therapeutics.

Achieving Energy Efficiency and Impact of SAR in a WBAN Through Optimal Placement of the Relay Node

Wireless Body Area Network (WBAN) is an emerging and promising specialized area in Wireless networks that deals with crucial health-related datasets. Unlike other wireless networks, as this type of network deals with medical facts, losing it is fatal. WBAN is a highly constrained network. Reducing energy consumption and enhancing lifetime are the two most important challenges of WBANs. One way to achieve these is by deploying relay nodes optimally in WBANs. Generally, a relay node is placed at the midpoint of the line joining the source and the destination (D) nodes. We show that such simplistic deployment of the relay nodes is not the optimal deployment, which can hamper the overall lifetime of WBANs. In this paper, we have investigated the best location to deploy a relay node on a human body. We assume that an adaptive decode and forward relay node (R) can move linearly between the source (S) and the destination (D) nodes. Moreover, the assumption is that a relay node can be deployed linearly and that the body part of a human is a flat surface and hard. We have investigated the most energy-efficient data payload size based on the optimally placed relay location. The impact of such a deployment on different system parameters, such as distance (d), payload (L), modulation scheme, specific absorption rate, and an end to end outage (O ) are examined as well. It is observed that in every aspect optimal deployment of the relay node performs an important role to enhance the lifetime of wireless body area networks. Sometimes linear relay deployment is very difficult to implement, especially on the different body parts of the human body. To address these issues, we have examined the optimal region for the relay node based on a 3D non-linear system model. The paper provides guidance for both linear and non-linear relay deployment along with the optimal data payload size under various circumstances and also considered the impact of specific absorption rates on the human body.

Pharmacological blockade of HDAC3 accelerates diabetic wound healing by regulating macrophage activation

AIMS

Here, we report the effect of histone deacetylase 3 (HDAC3) inhibition associated with macrophage activation, IL-1β expression, angiogenesis and wound healing in diabetic mice.

MAIN METHODS

To determine the expression of HDAC3 in diabetic mice wounds, hyperglycemia was induced in C57BL/6 mice with streptozotocin followed by induction of 6 mm wounds. To understand the effect of HDAC3 selective inhibitor, BG45, wound tissues were isolated for analysing M1/M2 markers expression, immune cells infiltration, angiogenesis and healing factors expression. CD11b⁺F4/80⁺ cells were sorted from the wound tissues and analysed for the expression of M1/M2 markers using RT-qPCR and flow cytometer. In cell based assays, HDAC3 expression was measured in macrophages stimulated with high glucose (HG) plus LPS. Macrophages treated with BG45 and HG + LPS were analysed for the expression of pro-IL-1β, mature IL-1β, oxidative stress and pro-inflammatory (M1) and anti-inflammatory (M2) factors.

KEY FINDINGS

HDAC3 was found to be upregulated in impaired diabetic mice wounds and in macrophages stimulated with HG + LPS. Topical application of BG45 loaded gel accelerated the wound healing in diabetic mice and was evident by improved expression of Collagen-1A, IL-10, TGF-β, and angiogenesis (CD31, VEGF). BG45 treatment decreased the expression of IL-1β, TNF-α, and IL-6 (M1 phenotype), reduced oxidative stress and promoted the expression of Arginase-1 and YM1/2 (M2 phenotype) in macrophages treated with HG + LPS. BG45 also improved the expression of CD11b⁺F4/80⁺CD206⁺ cells in wound tissues and reduced expression of inflammatory markers.

SIGNIFICANCE

HDAC3 is upregulated in diabetic mice wounds and HDAC3 selective inhibitor promotes the wound healing by regulating macrophage activation, angiogenesis and IL-1β.

Critical Analysis and Optimization of Stoichiometric Ratio of Drug-Coformer on Cocrystal Design: Molecular Docking, In Vitro and In Vivo Assessment

In this present research, an attempt has been made to address the influence of drug-coformer stoichiometric ratio on cocrystal design and its impact on improvement of solubility and dissolution, as well as bioavailability of poorly soluble telmisartan. The chemistry behind cocrystallization and the optimization of drug-coformer molar ratio were explored by the molecular docking approach, and theoretical were implemented practically to solve the solubility as well as bioavailability related issues of telmisartan. A new multicomponent solid form, i.e., cocrystal, was fabricated using different molar ratios of telmisartan and maleic acid, and characterized by SEM, DSC and XRD studies. The molecular docking study suggested that specific molar ratios of drug-coformer can successfully cluster with each other and form a specific geometry with favourable energy conformation to form cocrystals. Synthesized telmisartan-maleic acid cocrystals showed remarkable improvement in solubility and dissolution of telmisartan by 9.08-fold and 3.11-fold, respectively. A SEM study revealed the formation of cocrystals of telmisartan when treated with maleic acid. DSC and XRD studies also confirmed the conversion of crystalline telmisartan into its cocrystal state upon treating with maleic acid. Preclinical investigation revealed significant improvement in the efficacy of optimized cocrystals in terms of plasma drug concentration, indicating enhanced bioavailability through improved solubility as well as dissolution of telmisartan cocrystals. The present research concluded that molecular docking is an important path in selecting an appropriate stoichiometric ratio of telmisartan: maleic acid to form cocrystals and improve the solubility, dissolution, and bioavailability of poorly soluble telmisartan.

Neural crest cells development and neuroblastoma progression: Role of Wnt signaling

Neuroblastoma (NB) is one of the most common heterogeneous extracranial cancers in infancy that arises from neural crest (NC) cells of the sympathetic nervous system. The Wnt signaling pathway, both canonical and noncanonical pathway, is a highly conserved signaling pathway that regulates the development and differentiation of the NC cells during embryogenesis. Reports suggest that aberrant activation of Wnt ligands/receptors in Wnt signaling pathways promote progression and relapse of NB. Wnt signaling pathways regulate NC induction and migration in a similar manner; it regulates proliferation and metastasis of NB. Inhibiting the Wnt signaling pathway or its ligands/receptors induces apoptosis and abrogates proliferation and tumorigenicity in all major types of NB cells. Here, we comprehensively discuss the Wnt signaling pathway and its mechanisms in regulating the development of NC and NB pathogenesis. This review highlights the implications of aberrant Wnt signaling in the context of etiology, progression, and relapse of NB. We have also described emerging strategies for Wnt-based therapies against the progression of NB that will provide new insights into the development of Wnt-based therapeutic strategies for NB.

Hydrazides as Potential HDAC Inhibitors: Structure-activity Relationships and Biological Implications

Epigenetic modulations by HDACs are associated with multiple disease conditions. In this context, HDACs play vital roles in the progression of diseases including several cancers, neurodegenerative diseases, inflammatory diseases, and metabolic disorders. Though several HDAC inhibitors have been established as drug candidates, their usage has been restricted because of broad-spectrum inhibition, highly toxic character, and off-target adverse effects. Therefore, specific HDAC selectivity is essential to get rid of such adverse effects. Hydrazide-based compounds have already been proven to exert higher inhibitory efficacy and specific HDAC selectivity. In this article, the detailed structure-activity relationship (SAR) of the existing hydrazide-based HDAC inhibitors has been elucidated to gather crucial information that can be utilized further for the development of promising drug candidates for combating diverse diseases in the future.

Hypoxia alleviating platinum(IV)/chlorin e6-based combination chemotherapeutic-photodynamic nanomedicine for oropharyngeal carcinoma

Hypoxia is an important pathological hallmark of the tumor microenvironment, associated with metabolic alterations, cell proliferation, aggressiveness, metastasis, and therapy resistance in cancers. Hypoxia impedes the outcome of photodynamic therapy (PDT), which is largely dependent on molecular oxygen to generate cytotoxic ¹O₂. Here, a near-infrared light activatable, oxygen-generating nanomicellar PDT-chemotherapy system (mPPCPN Ms) constituted of amphiphilic mPEG-PLA, photosensitizer Ce6, and tetravalent platinum prodrug Pt(IV)-diazide was developed for oral squamous cell carcinoma. The polymer conjugate self-assemble to nanosize (115 ± 2.35 nm) micelles, which, upon irradiation (660 nm laser), activated Ce6, and photodecomposed to produce cytotoxic Pt(II), azidyl radical, and molecular oxygen. The strategically fabricated PDT-chemotherapy produced a strong antitumor response in vitro using oral squamous cell carcinoma and in vivo in oral cancer-xenografted mouse models, revealing its significant potential in chemo-photodynamic combination therapy with the benefit of reversing hypoxia.

Quantitative Structural Assessments of Potential Meprin β Inhibitors by Non-linear QSAR Approaches and Validation by Binding Mode of Interaction Analysis

The Zn2+-dependent endopeptidase meprin β is an astacin family metalloenzyme that belongs to the metzincin superclass of metalloproteases. The presence of a wide variety of meprin β substrates has enabled...

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (¹O₂) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.

Synthesis and appraisal of dalbergin-loaded PLGA nanoparticles modified with galactose against hepatocellular carcinoma: In-vitro, pharmacokinetic, and in-silico studies

Hepatocellular carcinoma (HCC) is a common malignancy which affects a substantial number of individuals all over the globe. It is the third primary cause of death among persons with neoplasm and has the fifth largest mortality rate among men and the seventh highest mortality rate among women. Dalbergin (DL) is described to be effective in breast cancer via changing mRNA levels of apoptosis-related proteins. DL belongs to neoflavonoids, a drug category with low solubility and poor bioavailability. We created a synthetic version of this naturally occurring chemical, DL, and then analyzed it using 1H-NMR, 13C-NMR, and LC-MS. We also made PLGA nanoparticles and then coated them with galactose. The design of experiment software was used to optimize DL-loaded galactose-modified PLGA nanoparticles. The optimized DL-nanoformulations (DLF) and DL-modified nanoformulations (DLMF) were analyzed for particle size, polydispersity index, shape, and potential interactions. In-vitro experiments on liver cancer cell lines (HepG2) are used to validate the anti-proliferative efficacy of the modified DLMF. The in-vitro research on HepG2 cell lines also demonstrated cellular accumulation of DLF and DLMF by FITC level. The in-vitro result suggested that DLMF has high therapeutic effectiveness against HCC. In-vivo pharmacokinetics and bio-distribution experiments revealed that DLMF excelled pristine DL in terms of pharmacokinetic performance and targeted delivery, which is related to galactose’s targeting activity on the asialoglycoprotein receptor (ASGPR) in hepatic cells. Additionally, we performed an in-silico study of DL on caspase 3 and 9 proteins, and the results were found to be −6.7 kcal/mol and −6.6 kcal/mol, respectively. Our in-silico analysis revealed that the DL had strong apoptotic properties against HCC.

Current trends in the use of human serum albumin for drug delivery in cancer

INTRODUCTION

Human serum albumin is the most abundant transport protein in plasma, which has recently been extensively utilized to form nanoparticles for drug delivery in cancer. The primary reason for selecting albumin protein as drug delivery cargo is its excellent biocompatibility, biodegradability, and non-immunogenicity. Moreover, the albumin structure containing three homologous domains constituted of a single polypeptide (585 amino acid) incorporates various hydrophobic drugs by non-covalent interactions. Albumin shows active tumor targeting via their interaction with gp60 and SPARC proteins abundant in the tumor-associated endothelial cells and the tumor microenvironment.

AREAS COVERED

The review discusses the importance of albumin as a drug-carrier system, general procedures to prepare albumin NPs, and the current trends in using albumin-based nanomedicines to deliver various chemotherapeutic agents. The various applications of albumin in the nanomedicines, such as NPs surface modifier and fabrication of hybrid/active-tumor targeted NPs, are delineated based on current trends.

EXPERT OPINION

Nanomedicines have the potential to revolutionize cancer treatment. However, clinical translation is limited majorly due to the lack of suitable nanomaterials offering systemic stability, optimum drug encapsulation, tumor-targeted delivery, sustained drug release, and biocompatibility. The potential of albumin could be explored in nanomedicines fabrication for superior treatment outcomes in cancer.

Lattice dynamics across the ferroelastic phase transition in Ba2ZnTeO6: a Raman and first-principles study

Structural phase transitions drive several unconventional phenomena including some illustrious ferroic attributes which are relevant for technological advancements. On this note, we have investigated the ferroelastic structural transition of perovskite-type trigonal Ba₂ZnTeO₆ across T_c ∼ 150 K. With the help of Raman spectroscopy and density-functional theory (DFT)-based calculations, we report new intriguing observations associated with the phase transition in Ba₂ZnTeO₆. We observed the presence of a central peak (quasi-elastic Rayleigh profile), huge softening in the soft mode, hysteretic phonon behavior, and signatures of coexistent phases. The existence of a central peak in Ba₂ZnTeO₆ is manifested by a sharp rise in the intensity of the Rayleigh profile concomitant with the huge damping (or softening) of the soft mode (at ∼31 cm^-1) near T_c, shedding light on the lattice dynamics during the phase transition. This is further corroborated by our phonon calculations that show that the soft mode (E_g) in the high-symmetry structure involving TeO₆ octahedral rotation (with Ba and Zn translation) condenses into A_g and B_g modes in the C2/m low-symmetry phase. While most of the phonon bands split below T_c confirming the phase transition, we observed thermal hysteretic behavior of phonon modes, which signifies the first-order nature of the transition and the presence of coexisting phases as corroborated by our temperature-dependent X-ray diffraction and specific heat measurements.

Multifunctional graphene oxide nanoparticles for drug delivery in cancer

Recent advancements in nanotechnology have enabled us to develop sophisticated multifunctional nanoparticles or nanosystems for targeted diagnosis and treatment of several illnesses, including cancers. To effectively treat any solid tumor, the therapy should preferably target just the malignant cells/tissue with minor damage to normal cells/tissues. Graphene oxide (GO) nanoparticles have gained considerable interest owing to their two-dimensional planar structure, chemical/mechanical stability, excellent photosensitivity, superb conductivity, high surface area, and good biocompatibility in cancer therapy. Many compounds have been functionalized on the surface of GO to increase their biological applications and minimize cytotoxicity. The review presents an overview of the physicochemical characteristics, strategies for various modifications, toxicity and biocompatibility of graphene and graphene oxide, current trends in developing GO-based nano constructs as a drug delivery cargo and other biological applications, including chemo-photothermal therapy, chemo-photodynamic therapy, bioimaging, and theragnosis in cancer. Further, the review discusses the challenges and opportunities of GO, GO-based nanomaterials for the said applications. Overall, the review focuses on the therapeutic potential of strategically developed GO nanomedicines and comprehensively discusses their opportunities and challenges in cancer therapy.

Olaparib@human serum albumin nanoparticles as sustained drug-releasing tumor-targeting nanomedicine to inhibit growth and metastasis in the mouse model of triple-negative breast cancer

Poly(ADP-ribose) polymerase inhibitor olaparib demonstrated therapeutic effectiveness in highly metastatic triple-negative breast cancer (TNBC). However, olaparib offers a weak therapeutic response in wild-type BRCA cancers due to the drug's poor bioavailability. Here, a bioinspired/active-tumor targeted nanoparticles system of human serum albumin with physical entrapment of olaparib was prepared via a low-energy desolvation technique using the crosslinker glutaraldehyde. The developed OLA@HSA NPs were nanosize (∼140 nm), kinetically stable with a low polydispersity (0.3), exhibited olaparib entrapment (EE 76.01 ± 2.53%, DL 6.76 ± 0.22%), and sustained drug release at pH 7.4 with an enhancement of drug release in acidic pH. OLA@HSA NPs decreased the half-maximal inhibitory concentrations (IC₅₀) of olaparib by 1.6, 1.8-fold in 24 h and 2.2, 2.4 folds in 48 h for human (MDA-MB 231) and mouse (4T1) TNBC cells, respectively, mediated by their enhanced time-dependent cellular uptake than free olaparib. The OLA@HSA-OA NPs induced concentration-dependent phosphatidylserine (apoptotic marker) externalization and arrested the cell population in the G2/M phase in both the tested cell lines at a higher level than free olaparib. The NPs formulation increased DNA fragmentation, mitochondrial membrane depolarization, and ROS generation than the free olaparib. The in vivo study conducted using 4T1-Luc tumor-bearing mice demonstrated strong tumor growth inhibitory potential of OLA@HSA NPs by elevating apoptosis ROS generation and reducing the level of the antiproliferative marker, Ki-67. OLA@HSA NPs reduced the occurrence of lung metastasis (formation of metastasis nodules decreased by ∼10 fold). OLA@HSA NPs could be a promising nanomedicine for the TNBC treatment.

HDAC6 inhibition attenuates renal injury by reducing IL-1β secretion and RIP kinase mediated necroptosis in acute oxalate nephropathy

BACKGROUND

Pathogenesis of acute kidney injury is driven by necro-inflammation, which is comprised of IL-1β mediated inflammation and RIP-1 mediated tubular necroptosis. HDAC6 is reported to regulate both inflammation and cell death. In the present study, we explored the role of HDAC6 in the lysosomal exocytosis of IL-1β and RIP-1 mediated necroptosis in the context of oxalate nephropathy.

METHODS

Raw 264.7 macrophages and NRK52E stimulated with oxalate crystals and LPS with or without HDAC6 inhibitor for in vitro experiments. Acute oxalate nephropathy was induced in C57BL/6 mice by injecting sodium oxalate (75 mg/kg). For the drug intervention study, Tubastain A (TSA) was given an hour before injection of sodium oxalate. Mice were sacrificed 24 hrs after the oxalate injection, blood and kidney were harvested. Blood samples were analyzed for BUN and IL-1β levels. Renal tissues were analyzed for histology, immunohistochemistry, RNA, and protein expression.

RESULTS

HDAC6 and IL-1β upregulated in crystal stimulated macrophages and acute oxalate nephropathy. Pre-treatment of macrophages with TSA reduced IL-1β in supernatant without affecting the expression of pro-IL-1β and mature IL-1β in cell lysate. The effect of TSA on IL-1β secretion was influenced by tubulin acetylation. Renal epithelial cell NRK52E stimulated with crystals showed upregulation of necroptosis pathway markers and concentration-dependent cell death. TSA inhibited RIP-1, RIP3, and MLKL expression along with p-MLKL in stimulated epithelial cells. TSA treatment of oxalate nephropathy mice showed decreased inflammation and tubular cell death by regulating IL-1β and necroptosis and reduced renal injury.

CONCLUSION

This study highlights the role of HDAC6 in regulating the tubulin-mediated secretion of IL-1β and RIP kinase mediated necroptosis in acute oxalate nephropathy.