Inhibition Of Isoforms Research Articles

Phosphodiesterase 4 Inhibition in Neuropsychiatric Disorders Associated with Alzheimer’s Disease

Cognitive disorders and psychiatric pathologies, particularly Alzheimer’s disease (AD) and Major depressive disorder (MDD), represent a considerable health burden, impacting millions of people in the United States and worldwide. Notably, comorbidities of MDD and anxiety are prevalent in the early stages of mild cognitive impairment (MCI), which is the preceding phase of Alzheimer’s disease and related dementia (ADRD). The symptoms of MDD and anxiety affect up to 80% of individuals in the advanced stages of the neurodegenerative conditions. Despite overlapping clinical manifestations, the pathogenesis of AD/ADRD and MDD remains inadequately elucidated. Until now, dozens of drugs for treating AD/ADRD have failed in clinical trials because they have not proven beneficial in reversing or preventing the progression of these neuropsychiatric indications. This underscores the need to identify new drug targets that could reverse neuropsychiatric symptoms and delay the progress of AD/ADRD. In this context, phosphodiesterase 4 (PDE4) arises as a primary enzyme in the modulation of cognition and mood disorders, particularly through its enzymatic action on cyclic adenosine monophosphate (cAMP) and its downstream anti-inflammatory pathways. Despite the considerable cognitive and antidepressant potential of PDE4 inhibitors, their translation into clinical practice is hampered by profound side effects. Recent studies have focused on the effects of PDE4 and its subtype-selective isoform inhibitors, aiming to delineate their precise mechanistic contributions to neuropsychiatric symptoms with greater specificity. This review aims to analyze the current advances regarding PDE4 inhibition—specifically the selective targeting of its isoforms and elucidate the therapeutic implications of enhanced cAMP signaling and the consequent anti-inflammatory responses in ameliorating the symptomatology associated with AD and ADRD.

Design, Synthesis, Anticancer Screening, and Mechanistic Study of Spiro-N-(4-sulfamoyl-phenyl)-1,3,4-thiadiazole-2-carboxamide Derivatives.

The present study aims to create spiro-N-(4-sulfamoyl-phenyl)-1,3,4-thiadiazole-2-carboxamide derivatives with anticancer activities. The in vitro anticancer evaluation showed that only the novel spiro-acenaphthylene tethered-[1,3,4]-thiadiazole (compound 1) exhibited significant anticancer efficacy as a selective inhibitor of tumor-associated isoforms of carbonic anhydrase. Compound 1 demonstrated considerable efficacy against the renal RXF393, colon HT29, and melanoma LOX IMVI cancer cell lines, with IC50 values of 7.01 ± 0.39, 24.3 ± 1.29, and 9.55 ± 0.51 µM, respectively. In comparison, doxorubicin exhibited IC50 values of 13.54 ± 0.82, 13.50 ± 0.71, and 6.08 ± 0.32 µM for the corresponding cell lines. Importantly, compound 1 exhibited lower toxicity to the normal WI 38 cell line than doxorubicin, with IC50 values of 46.20 ± 2.59 and 18.13 ± 0.93 µM, respectively, indicating greater selectivity of the target compound compared to the standard anticancer agent doxorubicin. Also, mechanistic experiments demonstrated that compound 1 exhibits inhibitory activity against human carbonic anhydrase hCA IX and XII, with IC50 values of 0.477 ± 0.03 and 1.933 ± 0.11 μM, respectively, indicating enhanced selectivity for cancer-associated isoforms over cytosolic isoforms hCA I and II, with IC50 values of 7.353 ± 0.36 and 12.560 ± 0.74 μM, respectively. Cell cycle studies revealed that compound 1 caused G1 phase arrest in RXF393 cells, and apoptosis experiments verified a substantial induction of apoptosis with significant levels of early and late apoptosis, as well as necrosis (11.69%, 19.78%, and 3.66%, respectively), comparable to those induced by the conventional cytotoxic agent doxorubicin, at 9.91%, 23.37%, and 6.16%, respectively. Molecular docking experiments confirmed the strong binding affinity of compound 1 to the active sites of hCA IX and XII, highlighting significant interactions with zinc-binding groups and hydrophobic residues. These findings underscore the target compound's potential as a viable anticancer agent via targeting CA.

Novel 3-Sulfonamide Dual-Tail Pyrrol-2-one Bridged Molecules as Potent Human Carbonic Anhydrase Isoform Inhibitors: Design, Synthesis, Molecular Modeling Investigation, and Anticancer Activity in MeWo, SK-BR-3, and MG-63 Cell Lines.

Novel 3-sulfonamide pyrrol-2-one derivatives containing two sulfonamide groups were synthesized via a one-pot, three-component method using trifluoroacetic acid as a catalyst. Structural confirmation was achieved using spectroscopic techniques. The compounds were tested against four selected human carbonic anhydrase isoforms (hCA I, hCA II, hCA IX, and hCA XII). Most derivatives showed significant selectivity for hCA II, with 4h, 4i, 4n, 4k, and 4j demonstrating enhanced activity due to methoxy and hydroxy group patterns. Compound 4o exhibited strong dual selectivity for hCA II and hCA IX, while 4l was the most effective inhibitor of hCA XII. Additionally, 4e showed a preference for hCA XII inhibition. Biological evaluation on MeWo, SK-BR-3, and MG-63 cancer cells showed that compound 4l was cytotoxic for MeWo cells without significantly affecting normal fibroblasts' viability. Compounds 4e, 4l, and 4o were shown to affect tumor cell viability in combination with doxorubicin in additional testing on MeWo cancer cells.

New 7-hydroxycoumarin acetamide derivatives as human carbonic anhydrase IX and XII inhibitors: Design, synthesis, biological evaluation and molecular docking studies.

Carbonic anhydrases (CAs) are crucial in regulating various physiological processes in the body. The overexpression of isoforms human carbonic anhydrases (hCA) IX and hCA XII is linked to tumour progression. The selective inhibition of CA IX and CA XII isoforms can result in the development of better cancer treatment strategies. The tail approach based on coumarin derivatives was known for selective inhibition of isoforms IX and XII. This study explores the potential of coumarin derivatives (7a-k, 8a-s and 9a-g) as selective hCA IX and hCA XII inhibitors. The synthesised derivatives exhibited potent and selective inhibition towards hCA IX and XII, with Ki values in the range of 0.58‒3.33 µM and 0.48‒2.59 µM, respectively. The oxime ether derivative 7d was found to be the most potent one against hCA IX, with a Ki value of 0.58 µM, and phenyl hydrazine derivative 8a, with a Ki value of 0.48 µM against hCA XII, was the most potent one among the synthesised molecules. The potent isoform-specific carbonic anhydrase IX and XII inhibition suggests that 7d and 8a can be taken further towards the development of potent anticancer agents.

Exploring the Inhibition of Toxoplasma gondii α-Carbonic Anhydrase by Sulfonamides: Insights into Potential Drug Targeting.

Toxoplasma gondii, the causative agent of toxoplasmosis, is a protozoan parasite capable of infecting a wide range of hosts, posing significant health risks, particularly to immunocompromised individuals and congenital transmission. Current therapeutic options primarily target the active tachyzoite stage but are limited by issues such as toxicity and incomplete efficacy. As a result, there is an urgent need for alternative therapies that can selectively target parasite-specific mechanisms critical for metabolic processes and host-parasite interactions. In this context, α-carbonic anhydrase (Tg_CA), an enzyme essential for T. gondii survival has emerged as a promising drug target. Tg_CA was successfully expressed and purified to evaluate its susceptibility to sulfonamide-based inhibitors, represented by compounds 1-24 and the AAZ-HCT series. These inhibitors demonstrated a broad spectrum of activity, with KI values ranging from 17.8 to 8450 nM. Several compounds exhibited moderate to high potency against Tg_CA; however, concerns regarding selectivity arose because of the inhibition of human isoforms, particularly CA I and CA II. Thus, although some inhibitors showed strong activity against Tg_CA, optimizing selectivity remains crucial for minimizing off-target effects and improving therapeutic efficacy. Further structural modifications may enhance selectivity and advance the development of effective treatments for toxoplasmosis.

Abstract IA008: Leveraging conformational dynamics for improved selectivity

Abstract Maximizing the clinical activity and combinability of oncogene inhibitors requires the development of molecules that can achieve necessary levels of target inhibition at a tolerated and feasible human dose. This is enabled by improving selectivity against off-targets and/or for the mutant form of the target over wild-type. While conventional structural insights can inform the design of selective drug candidates, there are often cases where clear selectivity hypotheses are not readily identifiable. Here, we present two examples illustrating how conformational dynamics can be leveraged to obtain improved selectivity for validated oncogene targets. The first example focuses on the selective inhibition of FGFR2, a well-established target in various cancers harboring FGFR2 fusions or rearrangements. Although clinical efficacy of pan-FGFR inhibitors has been demonstrated, their benefit is limited by FGFR1- and FGFR4- mediated toxicities. We leveraged differences in conformational dynamics between FGFR2 and other FGFRs observed through molecular dynamics simulations to enable the development of Lirafugratinib, the first FGFR2 selective inhibitor. Lirafugratinib inhibits FGFR2 with a high degree of selectivity in pre-clinical models. In cancer patients, Lirafugratinib achieves >95% FGFR2 occupancy at a dose of 70mg once daily, with minimal evidence of inhibition of other FGFR isoforms. This improved selectivity translates to higher objective response rates compared to pan-FGFR inhibitors across multiple tumor types harboring FGFR2 fusions or rearrangements. The second example illustrates mutant-selective targeting of PI3Kα, the most frequently mutated kinase in cancer. While non-mutant selective inhibitors have shown clinical efficacy, their benefit is limited by hyperglycemia caused by inhibition of wild-type PI3Kα. Conformational differences between mutant and wild-type PI3Kα were identified using structural insights combined with molecular dynamics simulations, leading to the discovery of RLY-2608- the first mutant-selective inhibitor of PI3Kα. RLY-2608 binds to a novel allosteric pocket and demonstrates mutant selective inhibition in pre-clinical models. RLY-2608 has a favorable pharmacokinetic profile in cancer patients, with dose-dependent increases in exposure and low peak to trough fluctuations, resulting in high levels of target coverage throughout the dosing interval. When combined with fulvestrant, this translates into a higher objective response rate and lower rate of hyperglycemia in patients with hormone-receptor positive, PI3Kα-mutant breast cancer compared to non-mutant selective PI3Kα inhibitors. These examples demonstrate the power of leveraging conformational dynamics to obtain selective target inhibition, ultimately translating into improved patient outcomes. Citation Format: James Watters. Leveraging conformational dynamics for improved selectivity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr IA008.

Discovery of Sulfanilamide-diazo Derivatives Incorporating Benzoic Acid Moieties as Novel Inhibitors of Human Carbonic Anhydrase II Activity.

Sulfonamides are widely used carbonic anhydrase inhibitors (CAIs) in clinical settings, however, their nonspecific inhibition of multiple carbonic anhydrase isoforms can lead to reduced efficacy and side effects. This study aimed to develop sulfanilamide-diazo derivatives incorporating benzoic acid moieties as novel inhibitors of hCA II activity to reduce side effects and enhance selectivity for different CA isozymes. We investigated the interaction between these derivatives and the hCA II isozyme via various spectroscopic and docking methods. The kinetic data demonstrates that compound 1 (C1) and compound 2 (C2) share a similar inhibitory strength against hCA II, effectively inhibiting its esterase activity through a noncompetitive mechanism with Ki values at low micromolar levels. Fluorescence measurements indicated that the synthesized compounds suppressed the inherent fluorescence of hCA II via a static quenching process, with each compound showing a singular binding site within the enzyme. Thermodynamic evidences highlight the significance of van der Waals interactions and hydrogen bonding in the binding process. The results of molecular docking indicated that both C1 and C2 effectively obstruct the entrance to hCA II's active site, with no significant differences in their binding conformations. While C1 and C2 exhibit CA inhibitory potency lower than that of sulfonamide compounds, this study offers valuable insights that could pave the way for the development of a promising scaffold for designing new carbonic anhydrase inhibitors.

Phase Ib study of the oral PI3Kδ inhibitor linperlisib in patients with advanced solid tumors.

Patients with advanced solid tumors have a suboptimal prognosis. This study investigated the safety and feasibility of linperlisib, a selective phosphatidylinositol 3-kinase delta isoform (PI3Kδ) inhibitor, for treating patients with advanced solid tumors. In this phase Ib, single-arm, open-label, multi-center clinical trial, patients with histologically confirmed advanced solid tumors from eight centers in China were enrolled to receive oral linperlisib (80mg/day). The primary endpoint was safety. Between August 2019 and June 2022, 94 patients were enrolled in the trial and received the study treatment. The most common (≥ 20%) treatment emergent adverse events (TEAEs) of all grades irrespective of causality were increased aspartate aminotransferase (AST) (26.6%), proteinuria (26.6%), decreased appetite (25.5%), increased alanine aminotransferase (ALT) (22.3%), weight loss (21.3%), and anemia (21.3%). The most common grade ≥ 3 TEAEs were diarrhea (4.3%), increased AST (3.2%), increased ALT (3.2%), neutropenia (3.2%), anemia (3.2%), increased blood alkaline phosphatase (3.2%). The objective response rate (ORR) was 1.1% (95% confidence interval [CI] 0.0-5.8), and the disease control rate (DCR) was 37.2% (95% CI 27.5-47.8). As of the data cutoff, the median follow-up time was 4.2months (95% CI 2.8-6.9). The median progression-free survival (PFS) was 1.85months (95% CI 1.79-1.88). The median overall survival (OS) was not reached. Linperlisib showed an acceptable safety profile and preliminary clinical benefit in patients with a range of advanced solid tumors. Further studies of linperlisib safety and efficacy are warranted.

In-vitro evidence indicating that IL-10 causes aging-related hypoalbuminemia via JAK1/STAT3 and CEBP-β

Albumin (ALB) has numerous vital physiological outcomes for healthy aging. A decrease in serum albumin, i.e., hypoalbuminemia, is one of the risk factors associated with aging, which affects physiological functioning. Hypoalbuminemia is the outcome of either decreased ALB synthesis or increased degradation. However, the potential mechanism controlling ALB's mRNA level expression in aged individuals is yet to be explored. We noted decreased serum ALB concentrations in aged individuals participating in our study, as compared to the young ones. We found that IL-10, a paradoxical inflammaging marker, reduced ALB concentration in HepG2 cells. Inhibiting the JAK/STAT3 signalling increased albumin mRNA suggesting its IL-10-driven regulation via JAK/STAT3 pathway. Albumin promotor analysis revealed the presence of a CEBP-β binding site. We showed that CEBP-β binds to the albumin promoter in an IL-10-dependent manner. Further, IL-10 increased the expressions of all CEBP-β isoforms, including the inhibitory isoform (LIP). The CEBP-β inhibition either by a functional inhibitor (i.e., quercetin) or shRNA silencing increased albumin mRNA in HepG2 cells. Our finding showed that IL-10 likely regulates albumin expression in a JAK/STAT3 and CEBP-β dependent manner in aging. A better understanding of the underlying condition can improve albumin protein levels and the well-being of the aged population.

Epoxytiglianes induce keratinocyte wound healing responses via classical protein kinase C activation to promote skin re-epithelialization

Epoxytiglianes are a novel class of diterpene esters. The prototype epoxytigliane, EBC-46 (tigilanol tiglate), is a potent anti-cancer agent in clinical development for local treatment of a range of human and animal tumors. EBC-46 also consistently promotes wound re-epithelialization at the treatment sites, mediated via activation of classical protein kinase C (PKC) isoforms. We have previously shown that epoxytiglianes stimulate proliferative and wound repopulation responses in immortalized human skin keratinocytes (HaCaTs) in vitro, abrogated by pan-PKC inhibitor, bisindolylmaleimide-1. In this study, we further investigate the specific PKC isoforms responsible for inducing such wound healing responses, following HaCaT treatment with 1.51 nM-15.1 µM EBC-46 or analogue, EBC-211. Classical PKC inhibition by GӦ6976 (1 μM), significantly attenuated epoxytigliane induced, HaCaT proliferation and wound repopulation at all epoxytigliane concentrations. PKC-βI/-βII isoform inhibition by enzastaurin (1 μM), significantly inhibited HaCaT proliferation and wound repopulation responses induced by both epoxytiglianes, especially at 1.51–151 nM. PKC-α inhibitor, Ro 31–8220 mesylate (10 nM), exerted lesser inhibitory effects on HaCaT responses. Epoxytigliane changes in key keratin (KRT17) and cell cycle (cyclin B1, CDKN1A) protein levels were partly attenuated by GӦ6976 and enzastaurin. GӦ6976 also inhibited increases in matrix metalloproteinase (MMP-1, MMP-7, MMP-10) activities. Phospho-PKC (p-PKC) studies confirmed that epoxytiglianes transiently activated classical PKC isoforms (p-PKCα, p-PKC-βI/-βII, p-PKCγ) in a dose- and time-dependent manner. By identifying how epoxytiglianes stimulate classical PKCs to facilitate keratinocyte healing responses and re-epithelialization, these findings support further epoxytigliane development as topical therapeutics for clinical situations involving impaired re-epithelialization, such as non-healing wounds in skin.

Inavolisib-Based Therapy in PIK3CA-Mutated Advanced Breast Cancer

BackgroundInavolisib is a highly potent and selective inhibitor of the alpha isoform of the p110 catalytic subunit of the phosphatidylinositol 3-kinase complex (encoded by PIK3CA) that also promotes the degradation of mutated p110α. Inavolisib plus palbociclib–fulvestrant has shown synergistic activity in preclinical models and promising antitumor activity in early-phase trials.MethodsIn a phase 3, double-blind, randomized trial, we compared first-line inavolisib (at an oral dose of 9 mg once daily) plus palbociclib–fulvestrant (inavolisib group) with placebo plus palbociclib–fulvestrant (placebo group) in patients with PIK3CA-mutated, hormone receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative locally advanced or metastatic breast cancer who had had relapse during or within 12 months after the completion of adjuvant endocrine therapy. The primary end point was progression-free survival as assessed by the investigator.ResultsA total of 161 patients were assigned to the inavolisib group and 164 to the placebo group; the median follow-up was 21.3 months and 21.5 months, respectively. The median progression-free survival was 15.0 months (95% confidence interval [CI], 11.3 to 20.5) in the inavolisib group and 7.3 months (95% CI, 5.6 to 9.3) in the placebo group (hazard ratio for disease progression or death, 0.43; 95% CI, 0.32 to 0.59; P<0.001). An objective response occurred in 58.4% of the patients in the inavolisib group and in 25.0% of those in the placebo group. The incidence of grade 3 or 4 neutropenia was 80.2% in the inavolisib group and 78.4% in the placebo group; grade 3 or 4 hyperglycemia, 5.6% and 0%, respectively; grade 3 or 4 stomatitis or mucosal inflammation, 5.6% and 0%; and grade 3 or 4 diarrhea, 3.7% and 0%. No grade 3 or 4 rash was observed. Discontinuation of any trial agent because of adverse events occurred in 6.8% of the patients in the inavolisib group and in 0.6% of those in the placebo group.ConclusionsIn patients with PIK3CA-mutated, hormone receptor–positive, HER2-negative locally advanced or metastatic breast cancer, inavolisib plus palbociclib–fulvestrant led to significantly longer progression-free survival than placebo plus palbociclib–fulvestrant, with a greater incidence of toxic effects. The percentage of patients who discontinued any trial agent because of adverse events was low. (Funded by F. Hoffmann–La Roche; INAVO120 ClinicalTrials.gov number, NCT04191499.)

Computational investigations of flavonoids as ALDH isoform inhibitors for treatment of cancer

ABSTRACT Human aldehyde dehydrogenases (ALDHs) are a group of 19 isoforms often overexpressed in cancer stem cells (CSCs). These enzymes play critical roles in CSC protection, maintenance, cancer progression, therapeutic resistance, and poor prognosis. Thus, targeting ALDH isoforms offers potential for innovative cancer treatments. Flavonoids, known for their ability to affect multiple cancer-related pathways, have shown anticancer activity by downregulating specific ALDH isoforms. This study aimed to evaluate 830 flavonoids from the PubChem database against five ALDH isoforms (ALDH1A1, ALDH1A2, ALDH1A3, ALDH2, ALDH3A1) using computational methods to identify potent inhibitors. Extra precision (XP) Glide docking and MM-GBSA free binding energy calculations identified several flavonoids with high binding affinities. MD simulation highlighted flavonoids 1, 2, 18, 27, and 42 as potential specific inhibitors for each isoform, respectively. Flavonoid 10 showed high binding affinities for ALDH1A2, ALDH1A3, and ALDH3A1, emerging as a potential multi-ALDH inhibitor. ADMET property evaluation indicated that the promising hits have acceptable drug-like profiles, but further optimization is needed to enhance their therapeutic efficacy and reduce toxicity, making them more effective ALDH inhibitors for future cancer treatment.

Pharmacological effect of Berotek and the leading mechanisms of Lung Pathology in miners Central Kazakhstan

In modern production conditions, industrial aerosols are still among the most common harmful occupational factors that determine the increased risk of developing occupational respiratory diseases among workers at industrial enterprises. The dust respiratory diseases are significantly common among workers in the mining and coal industries of Kazakhstan. In recent years, there has been a clear increase in the incidence of chronic dust bronchitis. The particular attention should be paid to such types of metal dust as dust of beryllium, vanadium, molybdenum, tungsten, cobalt and their compounds, under the influence of which not only peculiar damage to the lungs are observed, but also pronounced changes in other organs and systems. Dust of these metals, according to numerous authors, has a general toxic and toxic-allergic effect. An urgent problem of modern occupational medicine is the study of the role of exogenous and endogenous factors in the development of occupational pathology of the bronchopulmonary system. To identify groups at increased risk of developing dust pathology of the bronchopulmonary system, it is necessary to comprehensively study clinical and genetic factors, as well as determine the most significant diagnostic markers for the development of this pathology. An important advantage of inhaled anticholinergic drugs is the minimal frequency and severity of adverse events.The broncholytic effect is expressed in the form of inhibition of phosphodiesterase isoforms with a further increase in intracellular cAMP content and relaxation of smooth muscles of the respiratory tract. Immunomodulatory and anti-inflammatory effects of bronchodilators have also been established.

Structure based exploration of mitochondrial alpha carbonic anhydrase inhibitors as potential leads for anti-obesity drug development.

Obesity has emerged as a major health challenge globally in the last two decades. Dysregulated fatty acid metabolism and de novo lipogenesis are prime causes for obesity development which ultimately trigger other co-morbid pathological conditions thereby risking life longevity. Fatty acid metabolism and de novo lipogenesis involve several biochemical steps both in cytosol and mitochondria. Reportedly, the high catalytically active mitochondrial carbonic anhydrases (CAVA/CAVB) regulate the intercellular depot of bicarbonate ions and catalyze the rapid carboxylation of pyruvate and acetyl-co-A to acetyl-co-A and malonate respectively, which are the precursors of fatty acid synthesis and lipogenesis. Several in vitro and in vivo investigations indicate inhibition of mitochondrial carbonic anhydrase isoforms interfere in the functioning of pyruvate, fatty acid and succinate pathways. Targeting of mitochondrial carbonic anhydrase isoforms (CAVA/CAVB) could thereby modulate gluconeogenetic as well as lipogenetic pathways and pave way for designing of novel leads in the development pipeline of anti-obesity medications. The present review unveils a diverse chemical space including synthetic sulphonamides, sulphamates, sulfamides and many natural bioactive molecules which selectively inhibit the mitochondrial isoform CAVA/CAVB with an emphasis on major state-of-art drug design strategies. More than 60% similarity in the structural framework of the carbonic anhydrase isoforms has converged the drug design methods towards the development of isoform selective chemotypes. While the benzene sulphonamide derivatives selectively inhibit CAVA/CAVB in low nanomolar ranges depending on the substitutions on the phenyl ring, the sulpamates and sulpamides potently inhibit CAVB. The virtual screening and drug repurposing methods have also explored many non-sulphonamide chemical scaffolds which can potently inhibit CAVA. The review could pave way for the development of novel and effective anti-obesity drugs which can modulate the energy metabolism.

Rationally designed febuxostat-based hydroxamic acid and its pH-Responsive nanoformulation elicits anti-tumor activity

Attempts to furnish antitumor structural templates that can prevent the occurrence of drug-induced hyperuricemia spurred us to generate xanthine oxidase inhibitor-based hydroxamic acids and anilides. Specifically, the design strategy involved the insertion of febuxostat (xanthine oxidase inhibitor) as a surface recognition part of the HDAC inhibitor pharmacophore model. Investigation outcomes revealed that hydroxamic acid 4 elicited remarkable antileukemic effects mediated via HDAC isoform inhibition. Delightfully, the adduct retained xanthine oxidase inhibitory activity, though xanthine oxidase inhibition was not the underlying mechanism of its cell growth inhibitory effects. Also, compound 4 demonstrated significant in-vivo anti-hyperuricemic (PO-induced hyperuricemia model) and antitumor activity in an HL-60 xenograft mice model. Compound 4 was conjugated with poly (ethylene glycol) poly(aspartic acid) block copolymer to furnish pH-responsive nanoparticles (NPs) in pursuit of circumventing its cytotoxicity towards the normal cell lines. SEM analysis revealed that NPs had uniform size distributions, while TEM analysis ascertained the spherical shape of NPs, indicating their ability to undergo self-assembly. HDAC inhibitor 4 was liberated from the matrix due to the polymeric nanoformulation's pH-responsiveness, and the NPs demonstrated selective cancer cell targeting ability.

Glucoimines incorporating classical and non-classical carbonic anhydrase pharmacophores: Design, synthesis, conformational analysis, biological evaluation, and docking simulations

In this report, a series of glucoimines has been prepared by reaction of d-glucosamine and aromatic aldehydes incorporating classical and non-classical carbonic anhydrase pharmacophores. The conformational behavior of veratrole glucoimine was studied in solution and in crystalline form, by NMR and X-ray diffraction analysis, which revealed that pyranose ring adopted a 4C1 conformation. All glucoimines were tested against four isozymes of carbonic anhydrase: hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (tumor-associated isozymes). In this study, per-O-acetylated and deprotected sulfonamide were identified as potent inhibitors of tumor-associated carbonic anhydrase isoforms. Molecular docking simulation was performed inside the active site of hCA II to evaluate the binding modes of veratrole and sulfonamide glucoimines. The last ones demonstrated the most favorable docking scores, indicating strong binding affinity towards hCAII in correlation with experimental inhibition activities. Interestingly, interaction analyses revealed distinct binding modes for ligand-hCAII complexes primarily due to the sulfonamide group.

Study of Chalcogen Aspirin Derivatives with Carbonic Anhydrase Inhibitory Properties for Treating Inflammatory Pain.

Carbonic anhydrase (CA) inhibitors represent intriguing tools for treating pain. This study aims at studying the pharmacological profile of chalcogen bioisosteres of aspirin, as inhibitors of CA isoforms (hCA I, II, IV, VII, IX, and XII). Our results show that selenoaspirin (5) displayed markedly superior inhibitory potency across all tested isoforms compared to thioaspirin (7) and aspirin, with a strong selectivity against the isoform CA IX. X-ray crystallography confirmed that both compounds bind effectively within the active site of hCA II, revealing unique structural characteristics compared to those of aspirin. In a preclinical model of inflammatory pain, compound 7 exhibited a longer lasting antihyperalgesic effect than aspirin, though with a lower potency. Conversely, compound 5 exhibited both lower potency and efficacy than aspirin in reducing pain, which entailed both adverse effects. Nevertheless, the therapeutic potential of chalcogen-based aspirin derivatives as novel CA inhibitors deserves to be further explored for clinical applications.

Sclerostin inhibits Protein kinase C inhibitor GÖ6976 induced osteogenic differentiation of dental follicle cells

Human dental follicle cells (DFCs) as multipotent stem cells are currently investigated within the field of regenerative medicine considering their potential for the regeneration of dental tissues, bone defects caused by periodontal or degenerative diseases and the treatment of craniofacial disorders. However, molecular mechanisms of the differentiation into mineralizing cells are still inadequately understood. Previous studies have shown that GÖ6976, an inhibitor of classical isoforms of protein kinase C (PKC), enhanced ostogenic differentiation of DFCs. A possible mechanism for increased osteogenic differentiation could be the regulation of ossification inhibitors. This study therefore investigated whether the osteogenic differentiation inhibitor sclerostin (SOST) is regulated by GÖ6976 and whether the addition of sclerostin attenuates the stimulating effect of the PKC inhibitor. We demonstrated that the expression of the sclerostin gene decreased after PKC inhibition by GÖ6976 and that its gene expression is likely maintained by PKC via the BMP signaling pathway. Furthermore, supplementation of osteogenic differentiation medium with sclerostin impairs GÖ6976-induced differentiation of DFCs. Our data suggest that regulation of sclerostin mediates PKC inhibition-induced mineralization of DFCs.

Structural Study of Selectivity Mechanisms for JNK3 and p38α with Indazole Scaffold Probing Compounds.

Selectivity is a primary focus in medicinal chemistry for ATP-competitive kinase inhibitors due to the highly conserved ATP binding pockets in the kinome. A decade of medicinal chemistry efforts has been carried out to develop selective inhibitors for JNKs, resulting in the identification of numerous promising scaffolds that even exhibit isoform selectivity. Thiophene-indazole is one of the scaffolds explored for isoform selectivity. Some iterations of this scaffold have also shown selectivity for p38α. In this study, we utilized four compounds derived from thiophene-indazole to investigate the mechanisms of selectivity for JNK3 and p38α. We determined crystal structures of the inhibitors bound to either JNK3 or p38α and subjected them to molecular dynamics (MD) simulations to understand the binding mechanism and critical interactions that govern affinity and selectivity for these two important kinases. The findings from this study provides valuable information for improving current lead inhibitors and developing a new generation of JNK3 isoform inhibitors.

New Structural Features of Isatin Dihydrothiazole Hybrids for Selective Carbonic Anhydrase Inhibitors.

Chemotherapeutic agents have remained the first-line treatment option for advanced-stage cancers when surgery or radiation therapy is not viable. Human carbonic anhydrase (hCA) isoforms IX and XII have been validated as anticancer targets. In particular, hCA IX is overexpressed in several solid tumor cells. As a result, selective isoform inhibitors with high potency and low toxicity are sought after. Pursuing our investigation on new scaffolds as hCA-selective inhibitors, a new series of isatin thiazolidinone hybrids has been designed and synthesized. Their biological activity and selectivity toward hCA I, hCA II, hCA IX, and hCA XII were investigated. The results revealed an inhibitory activity in the nanomolar range on carbonic anhydrases IX and XII, and the nature of substitution in positions 3 and 5 of thiazolidinone appears to be crucial for the compounds' selectivity. Docking experiments have been applied to predict the binding mode of these new, promising derivatives.