The cytotoxic natural compound erianin binds to colchicine site of ß-tubulin and overcomes taxane resistance.

Erianin, a natural compound derived from Dendrobium, has shown significant anticancer properties against a wide range of cancer cells. Despite the identification of multiple mechanisms of action for erianin, none of these mechanisms fully account for its broad-spectrum effect. In this study, we aimed to identify the cellular target and underlying mechanism responsible for the broad-spectrum antitumor effects of erianin. We found that erianin effectively inhibited tubulin polymerization in cancer cells and purified tubulin. Through competition binding assays and X-ray crystallography, it was revealed that erianin bound to the colchicine site of ß-tubulin. Importantly, the X-ray crystal structure of the tubulin-erianin complex was solved, providing clear insight into the orientation and position of erianin in the colchicine-binding site. Erianin showed activity against paclitaxel-resistant cells, evidenced by G2/M cell cycle arrest, apoptosis-related PARP and Caspase-3 cleavage, and in vivo xenograft studies. The study concluded that erianin bound reversibly to the colchicine site of ß-tubulin, inhibited tubulin polymerization, and displayed anticancer activity against paclitaxel-resistant cells, offering valuable insights for further exploration as potential anticancer agents.

Structural optimizations on the 7H-pyrrolo[2,3-d]pyrimidine scaffold to develop highly selective, safe and potent JAK3 inhibitors for the treatment of Rheumatoid arthritis.

Janus Kinase 3 (JAK3) is important for the signaling transduction of cytokines in immune cells and is identified as potential target for treatment of rheumatoid arthritis (RA). Recently, we designed and synthesized two JAK3 inhibitors J1b and J1f, which featured with high selectivity but mild bioactivity. Therefore, in present study the structure was optimized to increase the potency. As shown in the results, most of the compounds synthesized showed stronger inhibitory activities against JAK3 in contrast to the lead compounds, among which 9a was the most promising candidate because it had the most potent effect in ameliorating carrageenan-induced inflammation of mice and exhibited low acute in vivo toxicity (MTD > 2 g/kg). Further analysis revealed that 9a was highly selective to JAK3 (IC50 = 0.29 nM) with only minimal effect on other JAK members (>3300-fold) and those kinases bearing a thiol in a position analogous to that of Cys909 in JAK3 (>150-fold). Meanwhile, the selectivity of JAK3 was also confirmed by PBMC stimulation assay, in which 9a irreversibly bound to JAK3 and robustly inhibited the signaling transduction with mild suppression on other JAKs. Moreover, it was showed that 9a could remarkably inhibited the proliferation of lymphocytes in response to concanavalin A and significantly mitigate disease severity in collagen induced arthritis. Therefore, present data indicate that compound 9a is a selective JAK3 inhibitor and could be a promising candidate for clinical treatment of RA.

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis.

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

Discovery of indoline-based derivatives as effective ROCK2 inhibitors for the potential new treatment of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and devastating lung disease with a median survival of only 3-5 years. Due to the lack of effective therapy, IPF threatens human health. Recently, increasing reports have indicated that Rho-associated coiled-coil protein kinases (ROCKs) play important roles in the development of IPF and might represent a novel target for the treatment of IPF. Herein, a new series of selective ROCK2 inhibitors based on indoline were designed and synthesized. Structural modification resulted in optimized compound 9b with an IC50 value of 6 nM against ROCK2 and the inhibition of collagen gel contraction. Cellular assays demonstrated that 9b could significantly suppress the expression of collagen I and α-SMA, and inhibited ROCK signaling pathway. Oral administration of compound 9b (10 mg/kg) exerted more significant anti-pulmonary fibrosis effects than nintedanib (100 mg/kg) and KD025 (100 mg/kg) in a bleomycin-induced IPF rat model, suggesting that 9b could serve as a potential lead compound for the treatment of IPF.

Design, synthesis and biological evaluation of purine-based derivatives as novel JAK2/BRD4(BD2) dual target inhibitors.

Based on the pharmacological synergy of JAK2 and BRD4 in the NF-κB pathway and positive therapeutic effect of combination of JAK2 and BRD4 inhibitors in treating MPN and inflammation. A series of unique 9H-purine-2,6-diamine derivatives that selectively inhibited Janus kinase 2 (JAK2) and BRD4(BD2) were designed, prepared, and evaluated for their in vitro and in vivo potency. Among them, compound 9j exhibited acceptable inhibitory activity with IC50 values of 13 and 22 nM for BD2 of BRD4 and JAK2, respectively. The western blot assay demonstrated that 9j performed good functional potency in the NF-κB pathway and the phosphorylation of p65, IκB-α, and IKKα/ß signal intensities were suppressed on RAW264.7 cell lines. Furthermore, 9j significantly improved the disease symptoms in a Ba/F3-JAK2V617F allograft model. Meanwhile, 9j was also effective in relieving symptoms in an acute ulcerative colitis model. Taken together, 9j was a potent JAK2/BRD4(BD2) dual target inhibitor and could be a potential lead compound in treating myeloproliferative neoplasms and inflammatory diseases.

In vitro and in vivo metabolic profiling of PD105, a PI3Kδ inhibitor, using UHPLC-Q-Exactive plus-MS.

PD105, a PI3Kδ inhibitor, is a candidate for the treatment of rheumatoid arthritis. This study aims to identify the metabolic profiling in vitro and in vivo by UHPLC-Q-Exactive Plus-MS.The in vitro metabolism of PD105 was studied by mouse liver microsomes and hepatocytes, while the in vivo metabolic profiling was obtained from mouse plasma, urine, and faeces. A total of 20 metabolites were tentatively identified based on accurate mass, fragment pathways, and characteristic fragment ions, including 4 in vitro and 20 in vivo.The proposed metabolic pathways of PD105 showed that there were 18 phase I metabolites and 2 phase II metabolites. The phase I metabolic pathways included oxidation, hydration, desaturation and oxidative dechlorination, while the phase II metabolic reactions were mainly methylation and arginine conjugation. Among them, oxidation was the main metabolic pathway of PD105.The comprehensive metabolic profiling contributed to further elucidation of pharmacological action and mechanism of PD105.

Comparative Pharmacokinetic Investigation on Multiple Active Aminoalcohol-Diterpenoid Alkaloids after Single Oral Administrations of Monomers and Aqueous Extract of Fuzi (Aconiti Lateralis Radix Praeparata) by UFLC-MS/MS.

To further study the aminoalcohol-diterpenoid alkaloids (ADAs) in Fuzi (Aconiti Lateralis Radix Praeparata), a simple and sensitive UFLC-MS/MS method was established and validated for the determination of five ADAs, aconine, mesaconine, hypaconine, deoxyaconine and fuziline, in rat plasma to compare the pharmacokinetic characteristics of pure ADAs and Fuzi decoction. After precipitating protein with methanol, plasma samples were isolated at 0.5 mL/min flow rate on Waters Acquity UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 µm). The mobile phase was composed of 0.1% formic acid-water and methanol with gradient elution. Mass spectrometric inspection was conducted on a 5500 UFLC-MS/MS system with an electrospray ionization source in patterns of positive ion and multiple reaction-monitoring (MRM). All calibration curves were proved to have acceptable linearity (r2 > 0.99) in linear ranges. Intra-day and inter-day precision and the accuracy met the requirements. The matrix effects of all analytes were between 85% and 115% of three concentration levels. This method has been under verification for comparative pharmacokinetic research after oral administration between aqueous extract of Fuzi and single pure ADAs. The results demonstrated that there are evident pharmacokinetic discrepancies between them, and administration in the extract form instead of pure form may contribute to higher absorption.

Degrading FLT3-ITD protein by proteolysis targeting chimera (PROTAC).

Clinical FLT3 mutations caused poor therapeutic benefits toward the present FLT3 inhibitors, and degradation of the FLT3 mutant protein may be a promising alternative approach to protect against acute myeloid leukemia (AML). Herein, we report the discovery of small molecule FLT3 degraders based on the proteolysis targeting chimera (PROTAC). FLT3 degraders were designed, synthesized, and evaluated for FLT3 degradation. Promising PF15 significantly inhibited the proliferation of FLT3-ITD-positive cells, induced FLT3 degradation and downregulated the phosphorylation of FLT3 and STAT5. An in vivo xenograft model and survival period evaluation verified the efficacy of PROTAC. These findings laid a robust foundation for FLT3-PROTAC molecules as an effective strategy for treating AML.

Design, synthesis and biological evaluation of novel FAK inhibitors with better selectivity over IR than TAE226.

In this study, 28 novel focal adhesion kinase (FAK) inhibitors were designed and synthesized based on FAK inhibitor TAE226. Compound 18b displayed good inhibition of FAK (IC50 = 45 nM) with at least 22 fold of selectivity over insulin receptor (IR, IC50 > 1000 nM) and exhibited potent anticancer activity against Hela, HCT116 and MDA-MB-231 cell lines with IC50 values of 0.27, 0.19 and 0.26 µM respectively, compared to TAE226 (2.68, 0.64 and 4.19 µM respectively). 18b also inhibited the clone formation and migration of HCT-116 cells, tube formation of HUVECs, and stimulated cell cycle arrest in the G2/M phase, inducing apoptosis by promoting ROS production. The FAK-Src-ERK signaling pathway was inhibited by 18b in a dose-dependent manner. Moreover, 18b showed adequate oral bioavailability of 16.37% and 75.90% tumor growth inhibition in the HCT116 xenograft model was observed. These results indicate that 18b is a promising selective inhibitor of FAK.

SKLB-14b, a novel oral microtubule-destabilizing agent based on hydroxamic acid with potent anti-tumor and anti-multidrug resistance activities.

A hydroxamic acid based microtubule-destabilizing agent (MDA) SKLB-14b was discovered in this study, which was derived from shortening the linker length of the HDAC6 and microtubule dual-target inhibitor SKLB-23bb. SKLB-14b exhibited low nanomolar IC50 values on a wide spectrum of human cancer cell lines including both sensitive and multidrug-resistant cell lines. Surprisingly, its anti-proliferative activity relied on the presence of the hydroxamic acid group but lost inhibitory activity against HDACs. SKLB-14b bound to the colchicine site of tubulin and could inhibit tubulin polymerization. It exhibited good metabolic stability in liver microsomes, no inhibitory effect on CYP450 isoenzymes and high oral bioavailability. In vivo experiments revealed that SKLB-14b was potent in both sensitive (A2780S, HCT116) and resistant (A2780/T) xenograft mice models. Furthermore, in the patient-derived tumor xenograft (PDX) models of osimertinib resistant non-small cell lung cancer (NSCLC), 50 mg/kg of SKLB-14b administered every twodays inhibited tumor growth by 70.6% without obvious toxicity, better than the 59.7% inhibition rate of paclitaxel. Mechanistically, we found that SKLB-14b exerted anti-tumor and anti-multidrug resistance effects in vitro and in vivo through cell cycle arrest and pro-apoptotic activities, as well as vascular disrupting activities. Therefore, we discovered that SKLB-14b, as a novel MDA based on hydroxamic acid, could serve as a potential drug candidate for cancer therapy which deserves further investigation.

Synthesis and biological evaluation of 6-(pyrimidin-4-yl)-1H-pyrazolo[4,3-b]pyridine derivatives as novel dual FLT3/CDK4 inhibitors.

FMS-like tyrosine kinase-3 (FLT3) and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have been proven to play a significant role in tumor therapy. Herein, based on the previously reported JAK2/FLT3 inhibitor 18e, we described the synthesis, structure-activity relationship and biological evaluation of a series of unique 6-(pyrimidin-4-yl)-1H-pyrazolo[4,3-b]pyridine derivatives that inhibited FLT3 and CDK4 kinases. The optimized compound 23k exhibited low nanomolar range activities with IC50 values of 11 and 7 nM for FLT3 and CDK4, respectively. In the MV4-11 xenograft tumor model, the tumor growth inhibition rate of 23k dosed at 200 mg/kg was 67%, suggesting that 23k possessed an antitumor therapeutic effect.

Identification of in vivo metabolites of a potential anti-rheumatoid arthritis compound, the quinazolinone derivative PD110, using ultra-high performance liquid chromatography coupled with Q-Exactive plus mass spectrometrys.

The objective of this study was to identify metabolites of PD110 by UHPLC-Q-Exactive Plus MS and determine its metabolic pathways in vivo.Mouse urine, faeces, and plasma samples were collected after an intraperitoneal administration of PD110 at a single dose of 30 mg·kg-1.The metabolites were detected and identified by UHPLC-Q-Exactive Plus MS and Compound DiscovererTM 2.0 software.In total, 44 metabolites (including 31 phase-I and 13 phase-II metabolites) were preliminarily identified according to the mass accuracy (<5 ppm) and comparison of their mass spectrometry profiles. Oxidation, glucuronide conjugation, and glucoside conjugation were the main metabolic pathways of PD110 in mice.This research first focussed on the biotransformation of PD110 in mice, and its metabolites may provide pivotal information for further pharmacological and clinical studies.

Metabolic profiling in liver microsomes and mice of E28, a potent FLT3 inhibitor.

The objective of this study was to clarify the species differences of metabolic stability of E28 in liver microsomes, and to study metabolic phenotypes of E28 in human liver microsomes by chemical inhibition method.The metabolites in plasma, urine, and faeces samples from mice received caudal vein intravenous were detected and identified by UHPLC-HRMS, and the tissue distribution was studied after oral administration.E28 was metabolised rapidly in liver microsomes of each species with a short half-live T1/2 and a moderate clearance, except for rats. The metabolic properties of E28 were similar in human and mouse liver microsomes. Data from metabolic phenotype studies indicated that CYP2D6, CYP3A4 and CYP2C9 were the main metabolic enzymes participating in the metabolism of E28.The main metabolic pathways implicated include oxidation, methylation, amide hydrolysis, acetylation, glucuronide conjugation.Tissue distribution studies showed that E28 could be detected in all organs and tissues after oral administration, with the highest level in the stomach and the lowest in the brain. In bone marrow cells, the concentration of E28 in all sample points were consistently higher than its half inhibitory concentration against MV4-11 tumour cells.

Design, synthesis, and biological evaluation of novel covalent inhibitors targeting focal adhesion kinase.

Forty-one new focal adhesion kinase (FAK) covalent inhibitors were designed and synthesized based on FAK inhibitor TAE226. Compound 11w displayed the highest inhibition of FAK with an IC50 value of 35 nM and exhibited potent anticancer activity against Hela, HCT116 and MDA-MB-231 cell lines with IC50 values of 0.41, 0.01 and 0.11 µM respectively, compared to TAE226 (2.68, 0.64 and 4.19 µM respectively). 11w also inhibited the clone formation and migration of HCT-116 cells and stimulated cell cycle arrest in the G2/M phase, inducing tumor cell apoptosis. Compound 11w formed a covalent bond with the Cys427 residue of FAK in a docking model, inhibiting the autophosphorylation of FAK and downstream proteins in a dose-dependent manner. Moreover, 11w showed adequate oral bioavailability of 21.02%. A 74.20% inhibition of tumor growth in the HCT116 xenograft model was also observed. These data indicate that 11w is a promising covalent inhibitor of FAK.

Flavonoids with Inhibitory Effects on NLRP3 Inflammasome Activation from Millettia velutina.

Eight new flavonoids, including two ß-hydroxy/methoxychalcones, velutones A and B (1 and 2), two 1,3-diarylpropan-1-ols, velutols C and D (3 and 4), a dihydroxychalcone, velutone E (5), a chalcone, velutone F (6), a furanoflavanone, velutone G (7), and a furanoflavonol, velutone H (8), and 14 known compounds were isolated from Millettia velutina. Their structures were determined by high-resolution electrospray ionisation mass spectrometry (HR-ESIMS) and spectroscopic data analyses and time-dependent density functional theory electronic circular dichroism (TD-DFT-ECD) calculations. Among the isolated constituents, compound 6 exhibited the most potent inhibitory effect (IC50: 1.3 µM) against nigericin-induced IL-1ß release in THP-1 cells. The initial mechanism of action study revealed that compound 6 suppressed NLRP3 inflammasome activation via blocking ASC oligomerization without affecting the priming step, which subsequently inhibited caspase-1 activation and IL-1ß secretion. Most importantly, compound 6 exerted potent protective effects in the LPS-induced septic shock mice model by improving the survival rate of mice and suppressing serum IL-1ß release. These results demonstrated that compound 6 had the potential to be developed as a broad-spectrum NLRP3 inflammasome inhibitor for the treatment of NLRP3-related disease.

Modulation of LPS-induced inflammation in RAW264.7 murine cells by novel isoflavonoids from Millettia pulchra.

Millettia pulchra is a renowned anti-inflammatory herbal medicine in southeast provinces of China. However, the underlying anti-inflammation mechanism remained incompletely understood. Herein, four new isoflavones, pulvones A-D and eleven reported constituents were isolated from the stems of Millettia pulchra with their structures being elucidated by HRMS and NMR analysis. The anti-inflammatory activities of pulvones A and C were further evaluated due to the better inhibitory activity on nitric oxide production in LPS-stimulated RAW264.7 cells and no obvious cytotoxicity to RAW264.7 cells. Western blot showed that pulvones A significantly decreased the levels of iNOS and COX-2 proteins and pulvones C only decreased the level of iNOS protein. ELISA analysis demonstrated that pulvones A inhibited the production of both interleukin-6 (IL-6) and IL-1ß while pulvones C showed better suppression effect on IL-1ß production in LPS-stimulated RAW264.7 cells. Then, their potential inhibitory effects on NF-κB pathway were tested in LPS-stimulated RAW264.7 cells. Immunofluorescence and western blot assay showed that pulvones A and C reduced the nuclear translocation of NF-κB(p65) and interrupted IκB phosphorylation. The ADP-Glo™ kinase assay showed pulvones A and C could directedly inhibit the IKKß kinase activity with the inhibitory rate of 40%, which were also verified by docking study. Collectively, these results suggested that pulvones A and C's anti-inflammatory effects were relevant to the interruption of NF-κB activation by inhibiting IKKß kinase.

Anti-inflammatory Ellagitannins from Cleidion brevipetiolatum for the Treatment of Rheumatoid Arthritis.

Six new ellagitannins, brevipetins B-G (5 and 7-11), and a new phenolic glucoside, brevipetin A (4), along with six known compounds were isolated from the traditional Chinese medicinal plant Cleidion brevipetiolatum. Their structures and absolute configurations were determined by spectroscopic analyses, chemical methods, and TD-DFT-ECD calculations. Compounds 5-11 exhibited NO inhibitory effects with IC50 values of 1.9-8.2 µM, and 9 showed the most potent inhibitory effect (IC50: 1.9 µM). An in vivo anti-inflammatory assessment of 9 showed that it exerts therapeutic effects in both the carrageenan-induced rat paw edema and collagen-induced arthritis (CIA) models at 50 mg/kg oral administration. The enhanced protein and mRNA expression levels of iNOS (inducible nitric oxide synthase) and COX-2 (cyclooxygenase-2) in LPS-stimulated RAW 264.7 cells were dose-dependently suppressed by 9. An anti-inflammatory mechanistic study revealed that 9 suppressed NF-κB activity by inhibiting IκBα phosphorylation and blocking translocation of p65 from the cytosol to the nucleus. Therefore, 9 might have the potential to be developed as a lead compound for relieving rheumatoid arthritis.

The in vivo pharmacokinetics, tissue distribution and excretion investigation of mesaconine in rats and its in vitro intestinal absorption study using UPLC-MS/MS.

1. Mesaconine, an ingredient from Aconitum carmichaelii Debx., has been proven to have cardiac effect. For further development and better pharmacological elucidation, the in vivo process and intestinal absorptive behavior of mesaconine should be investigated comprehensively. 2. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of mesaconine in rat plasma, tissue homogenates, urine and feces to investigate the in vivo pharmacokinetic profiles, tissue distribution and excretion. The intestinal absorptive behavior of mesaconine was investigated using in vitro everted rat gut sac model. 3. Mesaconine was well distributed in tissues and a mass of unchanged form was detected in feces. It was difficultly absorbed into blood circulatory system after oral administration. The insufficient oral bioavailability of mesaconine may be mainly attributed to its low intestinal permeability due to a lack of lipophilicity. The absorption of mesaconine in rat's intestine is a first-order process with the passive diffusion mechanism.

Separation of caffeoylquinic acids and flavonoids from Asteris souliei by high-performance counter-current chromatography and their anti-inflammatory activity in vitro.

Eleven compounds were successfully separated from Asteris souliei by using a two-step high-performance counter-current chromatography method. The first step involved a reversed phase isocratic counter-current chromatography separation using hexane/ethyl acetate/methanol/water (1:0.8:1:1 v/v/v/v), which produced three fractions, the first two of which were mixtures. The second step used step-gradient reversed-phase counter-current chromatography with hexane/butanol/ethyl acetate/methanol/water (1:0.5:3.5:1:4 v/v/v/v/v) initially followed by hexane/ethyl acetate/methanol/water (1:2:1:2 v/v/v/v) to separate Fraction 1 into seven compounds; and hexane/ethyl acetate/methanol/water (1:1:1:1.2 v/v/v/v) to separate Fraction 2 into three further compounds. The chemical structures of the separated compounds were identified by ESI-MS and NMR spectroscopy (1 H and 13 C). Baicalin (5), eriodictyol (7), apigenin-7-glycoside (8), quercetin (9), luteolin (10), and apigenin (11) showed obvious inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells at a concentration of 10 µg/mL.

Design and Synthesis of a Highly Selective JAK3 Inhibitor for the Treatment of Rheumatoid Arthritis.

Selective inhibition of Janus kinase 3 (JAK3) has been identified as an important strategy for the treatment of autoimmune disorders. Based on the unique cysteine 909 residue (Cys909) of JAK3 at the gatekeeper position, we have developed a new irreversible covalent inhibitor, III-4, which is highly potent and selective in targeting JAK3. Importantly, III-4 selectively inhibited JAK3 (IC50 = 57 ± 1.21 nM) over other JAKs (IC50 > 10 µM) and Cys909 kinome members (IC50 > 1 µM). A cellular selectivity study also confirmed that III-4 preferentially inhibited JAK3 over JAK1 in JAK/STAT signaling. Moreover, the fact that III-4 covalently modified the Cys909 residue in JAK3 was clearly validated by mass spectrometry and covalent docking analysis. Based on the favorable target profiles, the pharmacokinetic properties and its low toxicity, III-4 exhibited better efficacy than tofacitinib in impeding disease progression in CIA mice, without any significant adverse effects. Taken together, III-4 is a potent, selective, and durable inhibitor of JAK3 and has the potential for the treatment of inflammatory disorders and autoimmune diseases, such as rheumatoid arthritis.