Design, synthesis and biological evaluation of novel naphthoquinothiazole derivatives as potent antitumor agents through inhibiting STAT3.

The signal transducer and activator of transcription 3 (STAT3) has been established as a crucial drug target in the development of antitumor agents. In this study, a series of 21 derivatives of the STAT3 inhibitor napabucasin were designed and synthesized. Through preliminary screening against tumor cell lines, SZ6 emerged as the most potent compound with half maximal inhibitory concentration (IC50) values of 46.3 nM, 66.4 nM, and 53.8 nM against HCT116, HepG2, and Hela cells respectively. Furthermore, SZ6 effectively suppressed tumor invasion and migration in HCT116 cell assays by inducing S-phase arrest and apoptosis through inhibition of Protein Kinase B (PKB/AKT) activity and induction of reactive oxygen species (ROS). The mechanism underlying SZ6's action involves inhibition of STAT3 phosphorylation, which was confirmed by western blotting analysis. Additionally, surface plasmon resonance (SPR) and cellular thermal shift assay (CETSA) demonstrated direct binding between SZ6 and STAT3. Notably, in vivo studies revealed that SZ6 significantly inhibited tumor growth without any observed organ toxicity. Collectively, these findings identify SZ6 as a promising STAT3 inhibitor for colorectal cancer treatment.

Enhanced Turnover for the P450 119 Peroxygenase-Catalyzed Asymmetric Epoxidation of Styrenes by Random Mutagenesis.

A randomized library is constructed based on pET30a-CYP119-T214V plasmid. This library of random mutants of CYP119-T214V was screened by means of the reduced CO difference spectra and epoxidation of styrene. By using directed evolution, a new CYP119 quadruple mutant S148P/I161T/K199E/T214V is constructed, expressed, and purified. This quadruple mutant significantly increases the turnover rate and conversion for the asymmetric epoxidation of styrene and its derivatives. The kcat. value of cis-ß-methylstyrene epoxidation catalyzed by the quadruple mutant exhibits an approximately 10-fold increase, relative to the previously reported T213M mutant under the same conditions. This is the first engineered CYP119 peroxygenase for the epoxidation of cis-ß-methylstyrene with a high turnover rate. The proposed mechanism, on the basis of a molecular docking study, for the asymmetric epoxidation suggests that the introduction of an acidic amino acid side chain into the active site and a hydrophobic amino acid into the substrate channels of CYP119 peroxygenase might result in high efficiency for the formation of compound I, and its subsequent peroxygenation by reconstructing the hydrogen-bonding interaction and increasing the substrate affinity and access.

Discovery of novel anti-tuberculosis agents with pyrrolo[1,2-a]quinoxaline-based scaffold.

A series of small molecules with novel pyrrolo[1,2-a]quinoxaline-based scaffold was designed via molecular hybridization of privileged agents active against Mycobacterium tuberculosis. Twenty-three compounds were synthesized and investigated for their antitubercular activities in vitro where ten compounds showed appreciable activities and moderate cytotoxicity. Compound 12g with MIC values of 5 µg/ml as a representative may possess better oral bioavailability and indicated high permeability by the parallel artificial membrane permeation assay of the blood-brain barrier (PAMPA-BBB). Further, the determination of enzyme inhibition and molecular docking study indicated that InhA may be the biological target of the active compounds. The results suggest the pyrrolo[1,2-a]quinoxaline hybrids as potential antitubercular leads for the development of new antitubercular agents.

Design, synthesis and biological evaluation of novel pyrrole derivatives as potential ClpP1P2 inhibitor against Mycobacterium tuberculosis.

In an effort to discover novel inhibitors of M. tuberculosis Caseinolytic proteases (ClpP1P2), a combination strategy of virtual high-throughput screening and in vitro assay was employed and a new pyrrole compound, 1-(2-chloro-6-fluorobenzyl)-2, 5-dimethyl-4-((phenethylamino)methyl)-1H-pyrrole-3-carboxylate was found to display inhibitory effects against H37Ra with an MIC value of 77 µM. In order for discovery of more potent anti-tubercular agents that inhibit ClpP1P2 peptidase in M. tuberculosis, a series of pyrrole derivatives were designed and synthesized based on this hit compound. The synthesized compounds were evaluated forin vitrostudies against ClpP1P2 peptidase and anti-tubercular activities were also evaluated. The most promising compounds 2-(4-bromophenyl)-N-((1-(2-chloro-6-fluorophenyl)-2, 5-dimethyl-1H- pyrrolyl)methyl)ethan-1-aminehydrochloride 7d, ethyl 4-(((4-bromophenethyl) amino) methyl)-2,5-dimethyl-1-phenyl-1H-pyrrole-3-carboxylate hydrochloride 13i, ethyl 1-(4-chlorophenyl)-4-(((2-fluorophenethyl)amino)methyl)-2-methyl-5-phenyl-1H-pyrrole-3-carboxylate hydrochloride 13n exhibited favorable anti-mycobacterial activity with MIC value at 5 µM against Mtb H37Ra, respectively.

Engineering P450 Peroxygenase to Catalyze Highly Enantioselective Epoxidation of cis-ß-Methylstyrenes.

P450 119 peroxygenase and its site-directed mutants are discovered to catalyze the enantioselective epoxidation of methyl-substituted styrenes. Two new site-directed P450 119 mutants, namely T213Y and T213M, which were designed to improve the enantioselectivity and activity for the epoxidation of styrene and its methyl substituted derivatives, were studied. The T213M mutant is found to be the first engineered P450 peroxygenase that shows highly enantioselective epoxidation of cis-ß-methylstyrenes, with up to 91 % ee. Molecular modeling studies provide insights into the different catalytic activity of the T213M mutant and the T213Y mutant in the epoxidation of cis-ß-methylstyrene. The results of the calculations also contribute to a better understanding of the substrate specificity and configuration control for the regio- and stereoselective peroxygenation catalyzed by the T213M mutant.

Total Synthesis of Chiral Falcarindiol Analogues Using BINOL-Promoted Alkyne Addition to Aldehydes.

An enantioselective total synthesis of chiral falcarindiol analogues from buta-1,3-diyn-1-yltriisopropylsilane is reported. The key step in this synthesis is BINOL-promoted asymmetric diacetylene addition to aldehydes. The two chiral centers of the falcarindiol analogues can be produced by using the same kind of catalyst with high selectivity, and the final product can be obtained in only six steps.

BMP-2 induction of Dlx3 expression is mediated by p38/Smad5 signaling pathway in osteoblastic MC3T3-E1 cells.

Dlx3 is essential for osteoblast differentiation and bone formation, and its expression is regulated by bone morphogenetic protein-2 (BMP-2). However, the intimate mechanism of BMP-2 regulation of Dlx3 transcription in osteoblasts is still unknown. Considering the important roles of Smad5 and p38 in osteoblast differentiation, we hypothesized that Smad5 and p38 mediated BMP-2-induced Dlx3 transcription in osteoblasts. We found activation of Smad5 and p38 increased the expression of Dlx3, whereas knocking down Smad5 or inactivation of p38 inhibited BMP-2-induced Dlx3 expression. Both Smad5 and p38 were able to activate Dlx3 promoter activity and p38/Smad5 response elements were located from -698 to -368 in Dlx3 promoter. Two Smad5 binding sites (SBEI and SBEII, TGTCT box) were identified in this region by EMSA and ChIP assay. Deletions and mutagenesis study of the Dlx3 promoter region indicated that the TGTCT boxes are crucial for p38/Smad5-induced Dlx3 promoter activity. At last, we found a cross-talk between p38 and Smad5, and that activation of p38 is necessary for BMP-2-induced Smad5 phosphorylation and nuclear translocation. Overall, we provide a novel insight that BMP-2-induced Dlx3 expression is regulated by p38/Smad5 signaling pathway in osteoblasts.

Osteopontin knockdown inhibits αv,ß3 integrin-induced cell migration and invasion and promotes apoptosis of breast cancer cells by inducing autophagy and inactivating the PI3K/Akt/mTOR pathway.

BACKGROUND: Osteopontin (OPN) is associated with tumor formation, progression and metastasis, and increased OPN levels have been associated with poor survival in breast cancer. We investigated the mechanisms responsible for OPN activity, and the relationships between OPN expression and clinical parameters in breast cancer. METHODS: OPN mRNA and protein levels were compared in malignant and benign breast tumors by polymerase chain reaction (PCR) and immunohistochemistry, respectively, and levels in breast cancer cells were determined by PCR and western blotting. The effects of lentiviral-mediated knockdown of OPN on OPN and αv,ß3 integrin expression, cell invasion and migration, autophagy and apoptosis were analyzed in MDA-MB-231 cells. RESULTS: OPN expression increased with aggressiveness of breast cancer phenotype. OPN knockdown inhibited αv,ß3 integrin expression in MDA-MB-231 cells, with subsequent inhibition of cell migration and invasion. Knockdown also inhibited the PI3K/Akt/mTOR pathway, promoted expression of the autophagy-related gene products LC3 and Beclin 1, and increased apoptosis. OPN expression was positively associated with tumor grade and lymph node metastasis. CONCLUSION: These results suggest that knockdown of OPN may inhibit breast cancer metastasis by regulating αv,ß3 integrin expression and inducing autophagy and subsequent inhibition of PI3K/Akt/mTOR signaling, thus providing further insights into the complex mechanisms regulating tumor growth and metastasis.

The U.S. FDA approved cardiovascular drugs from 2011 to 2023: A medicinal chemistry perspective.

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. A total of 28 new molecular entities (NMEs) were approved by the U.S. Food and Drug Administration (FDA) for the treatment of cardiovascular diseases from 2011 to 2023. Approximately 25 % of the medications were sanctioned for the management of diverse vascular disorders. The other major therapeutic areas of focus included antilipemic agents (15 %), blood pressure disease (11 %), heart failure, hyperkalemia, and cardiomyopathy (7-8% each). Among all the approved drugs, there are a total of 22 new chemical entities (NCEs), including inhibitors, agonists, polymers, and inorganic compounds. In addition to NCEs, 6 biological agents (BLAs), including monoclonal antibodies, small interfering RNAs (siRNAs), and antisense oligonucleotides, have also obtained approval for the treatment of cardiovascular diseases. From this perspective, approved NCEs are itemized and discussed based on their disease, targets, chemical classes, major drug metabolites, and biochemical and pharmacological properties. Systematic analysis has been conducted to examine the binding modes of these approved drugs with their targets using cocrystal structure information or docking studies to provide valuable insights for designing next-generation agents. Furthermore, the synthetic approaches employed in the creation of these drug molecules have been emphasized, aiming to inspire the development of novel, efficient, and applicable synthetic methodologies. Generally, the primary objective of this review is to provide a comprehensive examination of the clinical applications, pharmacology, binding modes, and synthetic methodologies employed in small-molecule drugs approved for treating CVD. This will facilitate the development of more potent and innovative therapeutics for effectively managing cardiovascular diseases.

Exploration of novel isoxazole-fused quinone derivatives as anti-colorectal cancer agents through inhibiting STAT3 and elevating ROS level.

Colorectal cancer (CRC) is trending to be a major health problem throughout the world. Therapeutics with dual modes of action have shown latent capacity to create ideal anti-tumor activity. Signal transducer and activator of transcription 3 (STAT3) has been proved to be a potential target for the development of anti-colon cancer drug. In addition, modulation of tumor redox homeostasis through deploying exogenous reactive oxygen species (ROS)-enhancing agents has been widely applied as anti-tumor strategy. Thus, simultaneously targeting STAT3 and modulation ROS balance would offer a fresh avenue to combat CRC. In this work, we designed and synthesized a novel series of isoxazole-fused quinones, which were evaluated for their preliminary anti-proliferative activity against HCT116 cells. Among these quinones, compound 41 exerted excellent in vitro anti-tumor effect against HCT116 cell line with an IC50 value of 10.18 ± 0.4 nM. Compound 41 was proved to bind to STAT3 by using Bio-Layer Interferometry (BLI) assay, and can significantly inhibit phosphorylation of STAT3. It also elevated ROS of HCT116 cells by acting as a substrate of NQO1. Mitochondrial dysfunction, apoptosis, and cell cycle arrest, which was caused by compound 41, might be partially due to the inhibition of STAT3 phosphorylation and ROS production induced by 41. Moreover, it exhibited ideal anti-tumor activity in human colorectal cancer xenograft model and good safety profiles in vivo. Overall, this study provided a novel quinone derivative 41 with excellent anti-tumor activity by inhibiting STAT3 and elevating ROS level, and gave insights into designing novel anti-tumor therapeutics by simultaneously modulation of STAT3 and ROS.

Strategies for the Discovery of Oxazolidinone Antibacterial Agents: Development and Future Perspectives.

Oxazolidinones represent a significant class of synthetic bacterial protein synthesis inhibitors that are primarily effective against Gram-positive bacteria. The commercial success of linezolid, the first FDA-approved oxazolidinone antibiotic, has motivated researchers to develop more potent oxazolidinones by employing various drug development strategies to fight against antimicrobial resistance, some of which have shown promising results. Thus, this Perspective aims to discuss the strategies employed in constructing oxazolidinone-based antibacterial agents and summarize recent advances in discovering oxazolidinone antibiotics to provide valuable insights for potentially developing next-generation oxazolidinone antibacterial agents or other pharmaceuticals.

Discovery and SAR Study of Quinoxaline-Arylfuran Derivatives as a New Class of Antitumor Agents.

A novel class of quinoxaline-arylfuran derivatives were designed, synthesized, and preliminarily evaluated for their antiproliferative activities in vitro against several cancer cell lines and normal cells. The representative derivative QW12 exerts a potent antiproliferative effect against HeLa cells (IC50 value of 10.58 µM), through inducing apoptosis and triggering ROS generation and the accumulation of HeLa cells in vitro. Western blot analysis showed that QW12 inhibits STAT3 phosphorylation (Y705) in a dose-dependent manner. The BLI experiment directly demonstrated that QW12 binds to the STAT3 recombination protein with a KD value of 67.3 µM. Furthermore, molecular docking investigation showed that QW12 specifically occupies the pY+1 and pY-X subpocket of the SH2 domain, thus blocking the whole transmission signaling process. In general, these findings indicated that the study of new quinoxaline-aryfuran derivatives as inhibitors of STAT3 may lead to new therapeutic medical applications for cancer in the future.

SAR Study and Molecular Mechanism Investigation of Novel Naphthoquinone-furan-2-cyanoacryloyl Hybrids with Antitumor Activity.

A series of novel naphthoquinone-furan-2-cyanoacryloyl hybrids were designed; they were synthesized and preliminarily evaluated for their anti-proliferative activities in vitro against several cancer cell lines and normal cells. The most potent compound, 5c, inhibited the proliferation of HeLa cells (IC50 value of 3.10 ± 0.02 µM) and colony survival, and it induced apoptosis while having relatively weaker effects on normal cells. Compound 5c also triggered ROS generation and accumulation, thus partially contributing to the observed cell apoptosis. A Western blotting analysis demonstrated that compound 5c inhibited the phosphorylation of STAT3. Furthermore, a biolayer interferometry (BLI) analysis confirmed that compound 5c had a direct effect on STAT3, with a KD value of 13.0 µM. Molecular docking showed that 5c specifically occupied the subpockets in the SH2 domain, thereby blocking the whole transmission signaling process. Overall, this study provides an important structural reference for the development of effective antitumor agents.

Selective and sensitive detection and detoxification of Pd2+ in living cells with a water-soluble fluorescent probe.

Due to the cytotoxic potential of even low doses of Pd2+, the development of its detection and detoxification strategies is highly demanding. In this paper, we developed a water-soluble fluorescent probe IMQU-8 with a new scaffold for Pd2+ sensing. IMQU-8 can detect Pd2+ with high selectivity and sensitivity and has a good detection limit of 2.5 nM under physiological conditions. Its sensing mechanism has been revealed through job plot experiments and HRMS, FT-IR, 1H NMR and DFT calculations, which demonstrated that the N atoms of the pyridyl group and imino group are crucial for Pd2+ sensing. Fluorescence lifetime assessment indicated that IMQU-8 and IMQU-8-Pd have almost identical fluorescence lifetimes, implying that IMQU-8 undergoes static quenching toward Pd2+. Additionally, IMQU-8 has been successfully applied to image Pd2+ in living cells. Since IMQU-8 and its coordinated complex IMQU-8-Pd exhibit low toxicity, IMQU-8 has been applied for the detoxification of Pd2+ in living cells.

Tetra-imidazolium piperazinediium bis-(benzene-1,3,5-tricarboxyl-ate) dihydrate.

During the crystallization of the title compound, 4C(3)H(5)N(2) (+)·C(4)H(12)N(2) (+)·2C(9)H(3)O(6) (3-)·2H(2)O, the acidic protons were transferred to the imidazole and piperazine N atoms, forming the final 4:1:2:2 hydrated mixed salt. The mean planes of the three carboxyl-ate groups in the anion are twisted with respect to the the central benzene ring, making dihedral angles of 13.5 (1), 14.5 (1) and 16.9 (1)°. In the crystal, the component ions are linked into a three-dimensional network by a combination of inter-molecular N-H⋯O, O-H⋯O and weak C-H⋯O hydrogen bonds. Further stabilization is provided by π-π stacking inter-actions with centroid-centroid distances of 3.393 (2) Šand weak C=O⋯π inter-actions [O-centroid = 3.363 (2) Å].

Design and synthesis of novel pyrimidine derivatives as potent antitubercular agents.

The emergence of various drug-resistant Mycobacterium tuberculosis (Mtb) strains has necessitated the exploration of new drugs that lack cross-resistance with existing therapeutics. By screening the MedChemExpress bioactive compound library, ceritinib was identified as a compound with activity against Mtb H37Ra. Ceritinib had a MIC value of 9.0 µM in vitro and demonstrated in vivo efficacy in a BALB/c mouse model infected with autoluminescent H37Ra. Then, 32 novel ceritinib derivatives were synthesized, and their antimycobacterial activities were evaluated in vitro. The antimycobacterial activities of the synthesized compounds were drastically affected by substitutions at position 4 of the pyrimidine nucleus and were enhanced by the presence of 2-isopropoxy-5-methyl-4-(piperidin-4-yl)aniline at position 2 of the pyrimidine nucleus. The in vivo antitubercular activities of the three most potent compounds were evaluated. 5-Chloro-N2-(2-isopropoxy-5-methyl-4-(piperidin-4-yl) phenyl)-N4-(naph thalen-1-yl) pyrimidine-2,4-diamine (16j) remarkably reduced the Mtb burden of mice. This result suggested the potential of 16j as a novel drug with superior antitubercular activities. The results of experiments on the combination of sulfamethoxazole with 16j and in silico modeling suggest that dihydrofolate reductase is the potential molecular target of 16j.

The effects of osterix on the proliferation and odontoblastic differentiation of human dental papilla cells.

INTRODUCTION: Dental papilla cells (DPCs) are precursors of odontoblasts and have the potential to differentiate into odontoblasts. Osteoblasts and odontoblasts have many common characteristics. Osterix (Osx) is essential for osteoblast differentiation. However, no information is available for the effects of Osx on the odontoblastic differentiation of DPCs. The purpose of this study was to investigate the effects of Osx on the proliferation and odontoblastic differentiation of DPCs. METHODS: An immortalized human dental papilla cell (hDPC) line was used. Osx was stably overexpressed or knocked down in hDPCs with infection of lentiviral particles to determine its biological effects on hDPCs. The proliferation of cells was measured by the 5-ethynyl-2'-deoxyuridine incorporation assay and direct cell counting. Expressions of dentin sialophosphoprotein, nestin, dentin matrix protein 1, and alkaline phosphatase were detected by real-time polymerase chain reaction to determine the odontoblastic differentiation of cells. The mineralization ability of cells was evaluated by von Kossa staining and alkaline phosphatase activity assay. RESULTS: Overexpression of Osx retarded the proliferation of hDPCs, whereas knockdown of Osx increased the cell proliferation. Overexpression of Osx promoted the odontoblastic differentiation of hDPCs by up-regulating odontoblastic differentiation genes and increased the mineralization ability of hDPCs. Knockdown of Osx down-regulated odontoblastic differentiation genes and decreased the mineralization ability of hDPCs. CONCLUSIONS: Osx might function as a potential regulator for the proliferation and odontoblastic differentiation of hDPCs.