Xueying Liu

3,5,4′-tri-O-acetylresveratrol Ameliorates Seawater Exposure-Induced Lung Injury by Upregulating Connexin 43 Expression in Lung

The aim of the present study was to examine the effects of 3,5,4′-tri-O-acetylresveratrol on connexin 43 (Cx43) in acute lung injury (ALI) in rats induced by tracheal instillation of artificial seawater. Different doses (50, 150, and 450 mg/kg) of 3,5,4′-tri-O-acetylresveratrol were administered orally for 7 days before modeling. Four hours after seawater inhalation, histological changes, contents of TNF-α, IL-1β and IL-10, and the expression of Cx43 in lungs were detected. Besides, the gap junction communication in A549 cells and human umbilical vein endothelial cells (HUVECs) challenged by seawater was also evaluated. Histological changes, increased contents of inflammatory factors, upregulation in gene level, and deregulation in protein level of Cx43 in lungs stimulated by seawater were observed. On the other hand, pretreatment with 3,5,4′-tri-O-acetylresveratrol significantly inhibited infiltration of inflammation, development of pulmonary edema, and contents of inflammatory mediators in lungs. Above all, 3,5,4′-tri-O-acetylresveratrol upregulated the expression of Cx43 in both gene and protein levels, and its intermediate metabolite, resveratrol, also enhanced the gap junction communication in the two cell lines. The results of the present study suggested that administration of 3,5,4′-tri-O-acetylresveratrol may be beneficial for treatment of inflammatorycellsin lung.

LC-MS/MS method for the simultaneous determination of PA-824, moxifloxacin and pyrazinamide in rat plasma and its application to pharmacokinetic study.

A simple, sensitive and rapid LC-MS/MS method has been developed and validated for simultaneous determination of PA-824, moxifloxacin, and pyrazinamide in rat plasma using metronidazole as internal standard. Sample preparation involved a simple one-step protein precipitation with methanol, followed by centrifugation and evaporation of the organic solvent. The residue was redissolved in mobile phase and analyzed by LC-MS/MS. An Inertsil(®) ODS3 C18 column (150mm×4.6mm, 5μm), a mobile phase composed of methanol-0.03% TEA (triethylamine) in water (85:15, v/v), and a flow rate of 0.5mL/min were employed, and the total run time was 6.0min. The mass spectrometer was run in positive ion ESI-APCI combined mode using multiple reaction monitoring (MRM) to monitor the mass transitions. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The LLOQ was 1.0μg/mL for pyrazinamide and 0.1μg/mL for PA-824 and moxifloxacin. The recoveries obtained for PA-824, moxifloxacin and pyrazinamide were ≥85%. Intra-day and inter-day coefficients of variation were less than 10%. The method had been successfully applied to a pharmacokinetic study of fixed dose administration of PA-824, moxifloxacin, pyrazinamide and their combination in SD rat. Significant differences of Tmax, Cmax, AUC(0-t) and CLz/F were observed between the single and combined groups after equal dose of PA-824 and moxifloxacin administration, which revealed the possibility of drug-drug interaction (DDI) between the PaMZ combination.

Cabazitaxel-induced autophagy via the PI3K/Akt/mTOR pathway contributes to A549 cell death

Cabazitaxel has been used to treat castration-resistant prostate cancer since its approval by the US Food and Drug Administration in 2010. However, whether cabazitaxel may inhibit the proliferation of other tissue-derived cancer cells, and its underlying mechanism, remains unknown. In the present study, the A549 lung adenocarcinoma cancer cell line was exposed to cabazitaxel, in order to investigate its cytotoxic effect and determine the underlying mechanism. The results demonstrated that cabazitaxel was able to induce autophagy in A549 cells, as evidenced by the formation of autophagosomes, upregulated LC3-II expression and increased LC3 puncta. Cabazitaxel-induced autophagy had a cytotoxic effect on A549 cells, as evidenced by the induction of cell death and cell cycle arrest at G2/M phase, which was independent of the apoptotic pathway. Furthermore, transfection with Beclin1 small interfering RNA and treatment with the autophagy inhibitor 3-methyladenine protected cells from cabazitaxel-induced cell death, thus confirming that cabazitaxel-induced autophagy contributed to A549 cell death. In addition, cabazitaxel targeted the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway to induce autophagy, as indicated by reduced phosphorylation of Akt and mTOR. In conclusion, the present study demonstrated that cabazitaxel exerts a cytotoxic effect on A549 cells by acting on the PI3K/Akt/mTOR pathway to promote autophagic cell death. This result supports the potential use of cabazitaxel as a chemotherapeutic agent for the treatment of lung cancer.

Targeting the apoptotic Mcl-1-PUMA interface with a dual-acting compound

Despite intensive efforts in the search for small molecules with anti-cancer activity, it remains challenging to achieve both high effectiveness and safety, since many agents lack the selectivity to only act on cancer cells. The interface of two apoptotic proteins, myeloid cell leukemia-1 (Mcl-1) and p53 upregulated modulator of apoptosis (PUMA), has been recently affirmed as a target for treating cancers, as the disruption of Mcl-1-PUMA binding can reduce cancer cell survival and protect normal cells from apoptosis. However, therapeutic agents that target this interface are yet to be found. In this work, we combined pharmacophore modelling and biological tests to seek small molecules which target the Mcl-1-PUMA interface. For the first time, a small-molecule compound was identified. Its dual activity has been validated to reduce PUMA-dependent apoptosis while deactivating Mcl-1-mediated anti-apoptosis in cancer cells. Our results would provide a new avenue for the development of effective and safe anti-cancer agents.Despite intensive efforts in the search for small molecules with anti-cancer activity, it remains challenging to achieve both high effectiveness and safety, since many agents lack the selectivity to only act on cancer cells. The interface of two apoptotic proteins, myeloid cell leukemia-1 (Mcl-1) and p53 upregulated modulator of apoptosis (PUMA), has been recently affirmed as a target for treating cancers, as the disruption of Mcl-1-PUMA binding can reduce cancer cell survival and protect normal cells from apoptosis. However, therapeutic agents that target this interface are yet to be found. In this work, we combined pharmacophore modelling and biological tests to seek small molecules which target the Mcl-1-PUMA interface. For the first time, a small-molecule compound was identified. Its dual activity has been validated to reduce PUMA-dependent apoptosis while deactivating Mcl-1-mediated anti-apoptosis in cancer cells. Our results would provide a new avenue for the development of effective and safe anti-cancer agents.

Phloretin exerts hypoglycemic effect in streptozotocin-induced diabetic rats and improves insulin resistance in vitro

The present study investigated the possible antiobesity and hypoglycemic effects of phloretin (Ph). In an attempt to discover the hypoglycemic effect and potential mechanism of Ph, we used the streptozotocin-induced diabetic rats and (L6) myotubes. Daily oral treatment with Ph for 4 weeks significantly (P<0.05) reduced postprandial blood glucose and improved islet injury and lipid metabolism. Glucose consumption and glucose tolerance were improved by Ph via GOD–POD method. Western blot results revealed that the expression of Akt, PI3K, IRS-1, and GLUT4 were upregulated in skeletal muscle of type 2 diabetes (T2D) rats and in L6 myotubes by Ph. The immunofluorescence studies confirmed that Ph improved the translocation of GLUT4 in L6 myotubes. Ph exerted hypoglycemic effects in vivo and in vitro, hence it may play an important role in the management of diabetes.

Pharmacokinetics and tissue distribution study of PA-824 in rats by LC-MS/MS.

A simple, sensitive and rapid LC-MS/MS method has been developed and validated for determination of PA-824 in rat biological samples using darunavir as internal standard. Chromatographic separation was achieved on an Inertsil(®)ODS3 C18 column (150mm×4.6mm, 5μm) using gradient elution of methanol-0.1% ammonia in water (90:10, v/v) with fast gradient elution at a flow rate of 0.6mL/min and run time of 5min. The mass spectrometer was run in positive electrospray ionization (ESI) mode using multiple reaction monitoring (MRM) to monitor the mass transitions. The optimized ion transition pairs for quantitation were m/z360.1→m/z175.0 for PA-824, m/z548.5→m/z504.2 for IS. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, matrix effect and robustness. All validation parameters met the acceptance criteria according to regulatory guidelines. The LLOQ was 0.05μg/mL. The calibration curves showed a good linearity over the concentration range of 0.05-50μg/mL. The calibration curves for all biological samples showed good linearity (r(2)>0.9978) over the concentration ranges tested. The recoveries obtained for PA-824 were ≥88.8%. The developed method was successfully applied to investigate the pharmacokinetics and tissue distribution of PA-824 in rats following oral administration. It was also the first study to investigate the tissue distribution of PA-824 in rats following oral administration.

Synthesis, cytotoxic activity and binding model analysis of novel isoxazole-docetaxel analogues with C3′-N modification

Structure–activity relationship (SAR) studies confirm that modifications at C-3′ position can lead to the development of highly potent novel taxoids. We designed and synthesized a series of novel isoxazole-docetaxel analogues A1–A5 by introducing isoxazolyl groups to C3′-N position. All of the synthesized compounds exhibited similar to better cytotoxic activities than docetaxel against human cancer cell lines, Hela, A2780, A549, MCF-7, and SK-OV-3. These compounds also possessed higher inhibition than docetaxel against drug-resistant cancer cell lines, A2780-MDR and MCF-7-MDR. Binding model analysis of A1–A5 molecule to microtubule (MT) showed that these compounds were anchored to the active site, explaining their inhibitory effects on MT in vitro. The calculated binding free energy values were in positive correlation with the IC50 values of A1–A5 compounds against cancer cells. These results strongly support the statement that the introduction of isoxazolyl groups to C-3′ position indeed improves the cytotoxic activities of taxoids.

Drug–Drug Interactions Between PA-824 and Darunavir Based on Pharmacokinetics in Rats by LC–MS-MS

Currently, patients with co-infection with HIV and tuberculosis are treated with more than one drug. PA-824 a new chemical entity and a member of a class of compounds known as nitroimidazo-oxazines, has significant antituberculosis activity and a unique mechanism of action. Darunavir (PrezistaTM) is a new protease inhibitor of HIV-1. A simple, sensitive and rapid LC-MS-MS method has been developed and validated for simultaneous determination of PA-824 and darunavir. Chromatographic separation was achieved on Agilent Eclipse plus C18 column (100 mm × 2.1 mm, 3.5 μm) using gradient elution of acetonitrile-water (90:10, v/v) with fast gradient elution at a flow rate of 0.6 mL/min and run time of 4.5 min. The mass spectrometer was run in positive electrospray ionization mode using multiple reaction monitoring to monitor the mass transitions. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification, recovery and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The method had been successfully applied to a pharmacokinetic study of fixed dose administration of PA-824, darunavir and their combination in rats. The results indicated that when co-administration of darunavir could decrease the amount of PA-824 in vivo and extend the elimination half-life.

Study on pharmacokinetics and bioequivalence of Vonoprazan pyroglutamate in rats by liquid chromatography with tandem mass spectrometry

Vonoprazan Fumarate (TAK-438F) is a new and effective drug approved in Japan in 2014 for treatment and prevention of acid-related diseases (ARDs), which exhibits many advantages compared with traditional proton-pump inhibitors (PPIs). However, the clinical applications of TAK0-438F suffers limitation due to the lack of injection dosage form. Efforts to overcome this limitation lead to the systhesis of Vonoprazan pyroglutamate (TAK-438P) for its high water solubility and more potent antisecretory effect. This was the first report to establish and validate a reliable and sensitive LC-MS/MS method for the quantification of TAK-438P in rat plasma and tissues (heart, liver, spleen, liver, kidney, rain, stomach and small intestine). All the features of the developed method suggested it was within bioanalytical criteria recommended by regulatory authorities. Furthermore, the developed method was applied to the exploration of the bioequivalence between TAK-438P and TAK-438F, as well as the pharmacokinetics and tissue distribution of TAK-438P. The results showed that there was no significant differences between TAK-438P and TAK-438F after oral administration of the same dose. Besides, TAK-438P was rapidly absorbed and eliminated in rat plasma. And it was widely distributed and there was no long-term accumulation in most tissues. Notably, more than 2000ng/mL was observed in stomach 12h after oral administration. The high accumulation revealed that stomach was likely to be the target organs of TAK-438P.

CLZ-8, a potent small-molecular compound, protects radiation-induced damages both in vitro and in vivo

PUMA (p53 up-regulated mediator of apoptosis) is particularly important in initiating radiation-induced damage and apoptosis. It has been shown that inhibition of PUMA can provide a profound benefit for the long-term survival of the mice, without an increased risk of malignancies after irradiation. It becomes to be a potential target for developing an effective treatment aimed to protect cells from lethal radiation. CLZ-8, a novel small-molecular inhibition targeting PUMA, could have considerable protection against cell apoptosis and DNA damage. The aim of the present study is to evaluate CLZ-8s radioprotective ability to enhance survival rate of mice exposed to gamma radiation, prevent radiation-induced apoptosis, and repair DNA damage in cultured cells. We have determined the best effective dose in vivo is 200 mg/kg. This dose of CLZ-8 administered at 30 min before radiation can notably enhance mice survival rate. CLZ-8 ameliorates radiation-induced HUVEC cells damage and reduces apoptosis counts compared to vehicle-treated cells. Western blotting analysis indicates that CLZ-8 selectively inhibits overexpressed PUMA induced by radiation. The results demonstrate that CLZ-8 ameliorates radiation-induced cell depletion, promotes DNA recovery, and protects mice from radiation injury.