α-Mangostin reduced the viability of A594 cells in vitro by provoking ROS production through downregulation of NAMPT/NAD.

α-Mangostin (MAN) is a bioactive compound isolated from the inedible pericarp of a tropical fruit mangosteen (Garcinia mangostana Linn). It exhibits notable therapeutic potentials on lung cancers, but the underlying mechanisms are still largely unknown. This study was designed to further explore the mechanisms involved in cytotoxicity of MAN on A549 cells. Apoptosis and cell cycle distribution were analyzed by flow cytometry methods. The fluorescent probes DCFH-DA and JC-1 were used to assess the intracellular reactive oxidative species (ROS) and mitochondrial membrane potential statuses, respectively. The regulation of MAN on relevant pathways was investigated by immunoblotting assays. The results obtained indicated that MAN caused significant apoptosis and cell cycle arrest in A549 cells, which eventually resulted in inhibition on cell proliferation in vitro. All these phenomena were synchronized with escalated oxidative stress and downregulation of nicotinamide phosphoribosyltransferase/nicotinamide adenine dinucleotide (NAMPT/NAD). Supplementation with nicotinamide mononucleotide (NMN) and N-acetylcysteine (NAC) efficiently eased MAN-induced ROS accumulation, and potently antagonized MAN-elicited apoptosis and cell cycle arrest. The pro-apoptotic effect of MAN was further confirmed by increased expressions of cleaved caspase 3, 6, 7, and 9, and its effect on cell cycle progression was validated by the altered expressions of p-p38, p-p53, CDK4, and cyclin D1. The immunoblotting assays also demonstrated that NAC/NMN effectively restored these molecular changes elicited by MAN treatment. Collectively, this study revealed a unique anti-tumor mechanism of MAN by provoking ROS production through downregulation of NAMPT/NAD signaling and further validated MAN as a potential therapeutic reagent for lung cancer treatment.

Inhibition of NF-κB pathway in fibroblast-like synoviocytes by α-mangostin implicated in protective effects on joints in rats suffering from adjuvant-induced arthritis.

α-Mangostin (MG) is a bioactive compound isolated from mangosteen. This study was aimed to investigate effects of MG on adjuvant-induced arthritis (AA) in rats and decipher the underlying mechanisms. Clinical severity of AA was evaluated by paw oedema, arthritis score, and hematological parameters. Digital radiography (DR) and histological examinations were employed to assess joints destructions. Immune functions were evaluated by T cell subsets distribution. Effects on NF-κB pathway were investigated by immunohistochemical, western-blot and immunofluorescence methods both in vivo and vitro. It was found MG possessed superior anti-inflammatory effects in vivo, suggested by attenuated paw swelling, reduced inflammatory cells infiltration and decreased the secretion of TNF-α and IL-1ß in serum. Meanwhile MG inhibited fibrous hyperplasia, synovial angiogenesis, cartilage and bone degradation in AA rats. Although MG exerted little effects on CD4+ population, it greatly decreased IFN-γ positive cells and promoted expression of FOXP3 in immune organs, indicating restoration of Th1/Treg cells ratio and recovery of immune homeostasis in vivo. Inhibition of NF-κB induced by MG was indicated by reduced the expression of p-p65 and VEGF in synovium. In vitro experiments found MG at 10 µg/ml significantly suppressed the expression and phosphorylation of key proteins implicated in NF-κB pathway and inhibited nucleus translocation of p65. These changes led to increased apoptosis and proliferation inhibition of HFLS-RA cells. The results demonstrated regulation of immune functions was deeply involved in the therapeutic actions of MG on AA, and it's inhibition on NF-κB in fibroblast-like synoviocytes was associated to the protective effects on joints.

Reactive oxygen species mediated NF-κB/p38 feedback loop implicated in proliferation inhibition of HFLS-RA cells induced by 1,7-dihydroxy-3,4-dimethoxyxanthone.

1,7-Dihydroxy-3,4-dimethoxyxanthone (XAN) is a bioactive compound isolated from Securidaca inappendiculata Hassk. and exerts the inhibitory effects on fibroblast-like synoviocytes by targeting NF-κB and p38. This study was designed to elucidate mechanisms underlying the divergent regulation on the two pathways in HFLS-RA cells by XAN. Expressions of hallmark proteins and transcription of GADD45α mRNA were determined by Western-blot and RT-qPCR methods, respectively. Fluorescence staining was employed to evaluate intracellular oxidative stress. Effects of XAN and N-acetyl-l-cysteine (NAC) on the proliferation of cells were investigated by MTT assay, and pro-apoptotic effects of XAN were assessed by Annexin V-FITC/PI method. It was found XAN blocked NF-κB signaling in HFLS-RA cells shortly after treatment. Moreover, it up-regulated both transcription and expression of GADD45α, and subsequently activated p38 pathway. As time went on, XAN significantly promoted the generation of reactive oxygen species (ROS), which accompanied with sustained up-regulation of p-p38 and increased apoptosis. 48H later, dual-effects of XAN on NF-κB and p38 were reversed. As activation of p38 and increased apoptosis induced by XAN were antagonized by NAC, they were deemed as ROS mediated effects. Furthermore, the accumulated ROS should also account for the activation of NF-κB in the late stage of treatments via interfering in p38/MSK1/NF-κB feedback. Altogether, these findings suggested XAN-induced ROS contributed great importance to the proliferation inhibition of HFLS-RA cells by mediating NF-κB/p38 feedback loop and apoptosis, which provided us a panoramic view of potential target in the therapy of RA by XAN.

Astragaloside IV downregulates the expression of MDR1 in Bel­7402/FU human hepatic cancer cells by inhibiting the JNK/c­Jun/AP­1 signaling pathway.

Previous studies demonstrated that astragaloside IV (ASIV) is a potential P­glycoprotein (P­gp)­mediated multidrug resistance (MDR) reversal agent through mechanisms involving downregulation of the gene expression of mdr1. In order to investigate whether the c­Jun N­terminal kinase (JNK) signaling pathway is involved in the mechanism underlying ASIV­induced downregulated the expression of mdr1, the present study used 5­fluorouracil­resistant Bel­7402/FU human hepatic cancer cells as target cells. ASIV (0.1 mM) decreased the protein expression of phosphorylated (p)­JNK and p­c­Jun in the Bel­7402/FU cells, as determined using western blot analysis. Treatment with the JNK pathway inhibitor, SP600125, at a concentration of 11 µM, decreased the mRNA expression levels of mdr1 and P­gp, as determined using reverse transcription­quantitative polymerase chain reaction and western blot analyses, and similar effects were observed following exposure to ASIV. Furthermore, electrophoretic mobility shift assays demonstrated that the DNA­binding activity of activator protein­1 (AP­1) was decreased by 0.1 mM ASIV or 11 µM SP600125. Flow cytometric analysis revealed that 0.1 mM ASIV or 11 µM SP600125 increased the intracellular accumulation of fluorescent P­gp substrates, including rhodamine 123. Taken together, these results indicated that ASIV reversed the drug resistance of Bel­7402/FU cells by downregulating the expression of mdr1 via inhibition of the JNK/c­Jun/AP­1 signaling pathway.

[Neuroprotective effect of Nogo-66 receptor silencing in preterm rats with brain injury caused by intrauterine infection].

OBJECTIVE: To investigate the effect of Nogo-66 receptor (NgR) silencing with specific small interfering RNA (siRNA) on brain injury repair in preterm rats with brain injury caused by intrauterine infection and related mechanism of action. METHODS: The pregnant Sprague-Dawley rats (with a gestational age of 15 days) were selected, and premature delivery was induced by RU486 or lipopolysaccharide (LPS). The preterm rats delivered by those treated with RU486 were selected as the control group. The preterm rats with brain injury caused by intrauterine infection induced by LPS were divided into model, empty vector, and NgR-siRNA groups, with 36 rats in each group. The rats in the control and model groups were given routine feeding only, and those in the empty vector and NgR-siRNA groups were given an injection of lentiviral empty vector or NgR-siRNA lentivirus via the lateral ventricle on postnatal day 1 (P1) and then fed routinely. On P3, P7, and P14, 8 rats in each group were randomly selected and sacrificed to harvest the brain tissue. RT-PCR was used to measure the mRNA expression of NgR. Western blot was used to to measure the protein expression of active RhoA. The immunofluorescence histochemistry was used to determine the degree of activation of microglial cells and the morphology of oligodendrocyte precursor cells (OPCs). Hematoxylin and eosin staining was used to observe the pathological changes in brain tissue. The behavioral score was evaluated on P30. RESULTS: On P3, the NgR-siRNA group had significantly lower mRNA expression of NgR and protein expression of active RhoA in brain tissue than the model and empty vector groups (P<0.05). In each group, the mRNA expression of NgR was positively correlated with the protein expression of active RhoA (P<0.05). The results of immunofluorescence histochemistry showed that on P3, the NgR-siRNA group had a significantly reduced fluorescence intensity of the microglial cells labeled with CD11b compared with the model and empty vector groups (P<0.05). The OPCs labeled with O4 antibody in the four groups were mainly presented with tripolar cell morphology. The results of pathological examination showed a normal structure of white matter with clear staining in the periventriclar area in the control group, a loose structure of white matter with disorganized fibers and softening lesions in the model and empty vector groups, and a loose structure of white matter with slightly disorganized fibers, slight gliocyte proliferation, and no significant necrotic lesions in the NgR-siRNA group. As for the behavioral score, compared with the model and empty vector groups, the NgR-siRNA group had a higher score in the suspension test, a longer total activity distance, and greater mean velocity and number of squares crossed, as well as a shorter time of slope test and a shorter time and distance of activity in the central area (P<0.05), while there were no significant differences in these parameters between the NgR-siRNA and control groups (P>0.05). CONCLUSIONS: NgR silencing with specific siRNA can effectively silence the expression of NgR in pertem rats with brain injury caused by interauterine infection and has a significant neuroprotective effect in brain injury repair.

Regulation of MAPKs Signaling Contributes to the Growth Inhibition of 1,7-Dihydroxy-3,4-dimethoxyxanthone on Multidrug Resistance A549/Taxol Cells.

1,7-Dihydroxy-3,4-dimethoxyxanthone (XAN) is a bioactive compound isolated from Securidaca inappendiculata Hassk. and validated with antiproliferative activities on a panel of cancer cell lines. This study was designed to investigate its growth inhibitory effects on multidrug resistance (MDR) non-small cell lung carcinoma (NSCLC) cell line A549/Taxol and explore the possible linkage between modulation of MAPKs and the bioactivities. Its growth inhibitory potency on the cells was estimated by MTT assay, and flow cytometric analysis was employed to investigate its potential cell cycle arrest and proapoptosis effects. Expressions of hallmark proteins were assessed by Western-Blot method. The results showed A549/Taxol cells were sensitive to XAN. XAN inhibited the proliferation of A549/Taxol cells in the time and concentration dependent manners. It acted as a potent inducer of apoptosis and cell cycle arrest in the cells. Western-Blot investigation validated the proapoptosis and cell cycle arrest activities of XAN and the potential of MDR reversion. Upregulation of p38 by XAN, which accounted for the cell cycle arrest at G2 phase, and the downregulation of ERK associated with the proapoptosis activity were also revealed. Further analysis found p53 may be the central role mediated the bioactivities of MAPKs in A549/Taxol cells. Based on these evidences, a conclusion has been deduced that XAN could be a potential agent for MDR NSCLC therapy targeting specifically MAPKs.

Dosing-time contributes to chronotoxicity of clofarabine in mice via means other than pharmacokinetics.

To evaluate the time- and dose-dependent toxicity of clofarabine in mice and to further define the chronotherapy strategy of it in leukemia, we compared the mortality rates, LD50s, biochemical parameters, histological changes and organ indexes of mice treated with clofarabine at various doses and time points. Plasma clofarabine levels and pharmacokinetic parameters were monitored continuously for up to 8 hours after the single intravenous administration of 20 mg/kg at 12:00 noon and 12:00 midnight by high performance liquid chromatography (HPLC)-UV method. Clofarabine toxicity in all groups fluctuated in accordance with circadian rhythms in vivo. The toxicity of clofarabine in mice in the rest phase was more severe than the active one, indicated by more severe liver damage, immunodepression, higher mortality rate, and lower LD50. No significant pharmacokinetic parameter changes were observed between the night and daytime treatment groups. These findings suggest the dosing-time dependent toxicity of clofarabine synchronizes with the circadian rhythm of mice, which might provide new therapeutic strategies in further clinical application.

Comparison of the antioxidant activity amongst Gingko biloba extract and its main components.

OBJECTIVE: To compare the antioxidant activity amongst the extract of Ginkgo biloba (EGb) and its main components, flavonoids and terpenoids. METHODS: The induction of EGb, flavonoids and terpenoids on a typical antioxidant enzyme, glutamate cysteine ligase catalytic subunit (GCLC), in cell lines was detected by Western-blot. The effects of EGb, flavonoids and terpenoids on superoxide anion radical (O2*(-)), hydroxyl radical (OH*), rat erythrocyte hemolysis and lipid peroxidation of rat liver homogenate were determined by respective activity methods. RESULTS: EGb and flavonoids but not terpenoids were demonstrated significantly to induce the antioxidant enzyme (GCLC), directly scavenge O2*(-), OH* and inhibit rat erythrocyte hemolysis and lipid peroxidation of rat liver homogenate. Compared these antioxidant activities between EGb and flavonoids, the activities of flavonoids were weaker than those of EGb, which contains similar dose of flavonoids. CONCLUSION: EGb has stronger antioxidant activities than flavonoids, but terpenoids did not show antioxidant activity in this research.