Alpinetin suppresses proliferation of human hepatoma cells by the activation of MKK7 and elevates sensitization to cis-diammined dichloridoplatium

Conserved gatekeeper methionine regulates the binding and access of kinase inhibitors to ATP sites of MAP2K1, 4, and 7: Clues for developing selective inhibitors

Mitogen-activated protein kinase kinases (MAP2Ks) 1, 4, and 7 are potential targets for treating various diseases. Here, we solved the crystal structures of MAP2K1 and MAP2K4 complexed with covalent inhibitor 5Z-7-oxozeaenol (5Z7O). The elucidated structures showed that 5Z7O was non-covalently bound to the ATP binding site of MAP2K4, while it covalently attached to cysteine at the DFG-1 position of the deep ATP site of MAP2K1. In contrast, we previously showed that 5Z7O covalently binds to MAP2K7 via another cysteine on the solvent-accessible edge of the ATP site. Structural analyses and molecular dynamics calculations indicated that the configuration and mobility of conserved gatekeeper methionine located at the central ATP site regulated the binding and access of 5Z7O to the ATP site of MAP2Ks. These structural features provide clues for developing highly potent and selective inhibitors against MAP2Ks. Abbreviations: ATP, adenosine triphosphate; FDA, Food and Drug Administration; MAP2Ks, mitogen-activated protein kinase kinases; MD, molecular dynamics; NSCLC, non-small cell lung cancer; 5Z7O, 5Z-7-oxozeaenol; PDB, protein data bank; RMSD, root-mean-square deviation.

LncRNA PCED1B-AS1 mediates miR-3681-3p/MAP2K7 axis to promote metastasis, invasion and EMT in gastric cancer

BACKGROUND

LncRNA PCED1B-AS1 is abnormally expressed in multiple cancers and has been confirmed as an oncogene. Our study aimed to investigate the regulatory mechanism of lncRNA PCED1B-AS1 in gastric cancer.

METHODS

TCGA database was used to analyze the abnormal expression of lncRNA PCED1B-AS1 in gastric cancer. By database prediction and mass spectrometric analysis, miR-3681-3p and MAP2K7 are potential downstream target molecules of lncRNA PCED1B-AS1 and verified by dual-luciferase report assay. RT-qPCR analysis and western blot were performed to detect the expressions of PCED1B-AS1 and MAP2K7 in gastric cancer cell lines and tissues. CCK-8 kit was applied to measure the cell viability. Wound healing and Transwell experiment were used to detect the migration and invasion. Western blot and immunohistochemical staining were performed to detect the expressions of EMT-related proteins in tissues. The changes of tumor proliferation were detected by xenograft experiment in nude mice.

RESULTS

PCED1B-AS1 expression was higher but miR-3681-3 expression was lower in gastric cancer cell lines or tissues, compared to normal group. Function analysis verified PCED1B-AS1 promoted cell proliferation and inhibited cell apoptosis in gastric cancer cells in vitro and in vivo. LncRNA PCED1B-AS1 could bind directly to miR-3681-3p, and MAP2K7 was found to be a downstream target of miR-3681-3p. MiR-3681-3p mimics or si-MAP2K7 could partly reverse the effect of PCED1B-AS1 on gastric cancer cells.

CONCLUSION

PCED1B-AS1 accelerated cell proliferation and inhibited cell apoptosis through sponging miR-3681-3p to upregulate MAP2K7 expression in gastric cancer, which indicated PCED1B-AS1/miR-3681-3p/MAP2K7 axis may serve as a potential therapeutic target for gastric cancer.

Active compounds of Caodoukou () inhibit the migration, invasion and metastasis of human pancreatic cancer cells by targeting phosphoinosmde-3-kinase/ protein kinase B/mammalian target of rapamycin pathway

OBJECTIVE

To detect the effects of active compounds of Caodoukou () (ACAK) on the proliferation, migration and invasion of pancreatic cancer, and explain the possible molecular mechanism of ACAK interacting with these processes.

METHODS

Cell counting kit-8 method, cell scratch repair experiment, Transwell migration and invasion experiment, immunohistochemistry, western blot assay and real-time polymerase chain reaction experiment were used to evaluate the effect of ACAK on the proliferation, migration and invasion of pancreatic cancer cells. The levels of active molecules involved in the phosphoinosmde-3-kinase (PI3K)/Akt/the mammalian target of rapamycin (mTOR) signal transduction were detected by Western blot assay. In addition, the function of ACAK was evaluated by xenotransplantation tumor model in nude mice.

RESULTS

The inhibitory effect of ACAK on the proliferation of pancreatic cancer cells showed certain time-dose dependence. The results of scratch repair test, Transwell test, Western blotting and real time polymerase chain reaction assay showed that ACAK could inhibit the migration and invasion of pancreatic cancer cells . In addition, the regulatory effect of ACAK on epithelial-mesenchymal transition (EMT) is partly attributed to PI3K/Akt/mTOR signaling pathway. The experimental results showed that ACAK regulated the development of pancreatic cancer.

CONCLUSIONS

ACAK can partly inhibit the activity of EMT and matrix metallopeptidases by down-regulating the downstream proteins of PI3K/Akt/mTOR signal pathway, thus inhibiting the ability of migration and invasion of pancreatic cancer.

Alpinetin: a Dietary Flavonoid with Diverse Anticancer Effects

Cancer is  a global burden and mechanistically complex disease with a plethora of genetic, physiological, metabolic, and environmental alterations. The development of dietary nutraceuticals into cancer chemotherapeutics has emerged as a new paradigm in cancer treatment. Alpinetin (ALPI) is a novel flavonoid component of multiple edible and medicinal plants and possesses a wide range of biological and pharmacological activities including antibacterial, anti-hemostatic, anti-oxidative, anti-hepatotoxic, stomachic, immunosuppressive, and anti-inflammatory. Recently, ALPI has been reported as a bioactive dietary nutraceutical with promising anticancer activity in various human cancers through multiple mechanisms. The purpose of this review is to compile the data on natural sources of ALPI, and its anticancer activity including cellular targets and anticancer mechanism in various human cancers. Moreover, this review will set the stage for further design and conduct pre-clinical and clinical trials to develop ALPI into a lead structure for oncological therapy.

Alpinetin: A Review of Its Pharmacology and Pharmacokinetics

Flavonoids isolated from medicinal herbs have been utilized as valuable health-care agents due to their virous biological applications. Alpinetin is a natural flavonoid that emerges in many widely used medicinal plants, and has been frequently applied in Chinese patent drugs. Accumulated evidence has demonstrated that alpinetin possesses a broad range of pharmacological activities such as antitumor, antiinflammation, hepatoprotective, cardiovascular protective, lung protective, antibacterial, antiviral, neuroprotective, and other properties through regulating multiple signaling pathways with low systemic toxicity. However, pharmacokinetic studies have documented that alpinetin may have poor oral bioavailability correlated to its extensive glucuronidation. Currently, the reported pharmacological properties and pharmacokinetics profiles of alpinetin are rare to be scientifically reviewed. In this article, we aimed to highlight the mechanisms of action of alpinetin in various diseases to strongly support its curative potentials for prospective clinical applications. We also summarized the pharmacokinetics properties and proposed some viable strategies to convey an appreciable reference for future advances of alpinetin in drug development.

Alpinetin Protects Chondrocytes and Exhibits Anti-Inflammatory Effects via the NF-κB/ERK Pathway for Alleviating Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease which is greatly affected by the inflammatory response triggered by the NF-κB signaling pathway. Alpinetin (APT) is a natural flavonoid compound, which has been reported to have many important biological activities such as antibacterial, antitumor, and anti-inflammatory. However, the action of its effect on chondrocytes in OA has yet to be elucidated. In this study, we investigated APT's anti-inflammatory action. The effects of APT on cell viability and cytotoxicity of rat chondrocytes was investigated by CCK8. Western blotting, qRT-PCR, and immunofluorescent staining were used to elucidate the molecular mechanisms and signaling pathways of APT mediating anti-inflammatory effects on chondrocytes. An OA model was induced by destabilization of the medial meniscus (DMM) in rats, then APT was injected into the knee articular cavity to examine its anti-inflammatory effects in vivo. These results showed that APT could reduce the TNF-α-induced increase of MMP-13 and ADAMTS-5 and decrease of COL2A1 levels. APT antagonized TNF-α-induced down-regulation of BCL-2 and CDK1. Further studies have shown that APT simultaneously repressed cell nucleus translocation of p65 and the phosphorylation of IκB and activated the phosphorylation of ERK. In vivo, APT suppressed cartilage matrix degradation. In conclusion, APT appears to favorably modulate anti-inflammatory effects in chondrocytes making it a promising compound for OA treatment. Graphical Abstract Inhibitory effects of Alpinetin on TNF-α-induced NF-κB activation resulted in destruction of cartilage in rat OA chondrocytes in vitro. The TNF-α receptor were stimulated by TNF-α, activating the cytoplasmic IκBα kinases(IKKS), then IKKs will be phosphorylated, and subsequently degraded by the ubiquitin-proteasome system. NF-κB transfer to the nucleus and bind various NF-κB regulates the NF-κB recognition site in the promoter region. Which triggers the gene expression of pro-inflammatory and pro-apoptotic. However, Alpinetin could inhibits the NF-κB signaling pathway in different ways: APT inhibits IκBα phosphorylation, preventing phosphorylated ubiquitination of IκBα further. Moreover, APT blocks translocation of the activated NF-κB to the nucleus, to protect the cartilage tissue from damage.

Differential effects of cisplatin combined with the flavonoid apigenin on HepG2, Hep3B, and Huh7 liver cancer cell lines

The potential of apigenin (APG) to enhance cisplatin's (CDDP) chemotherapeutic efficacy was investigated in HepG2, Hep3B, and Huh7 liver cancer cell lines. The presence of 20 μM APG sensitized all cell lines to CDDP treatment (degree of sensitization based on the MTT assay: HepG2>Huh7>Hep3B). As reflected by sister chromatid exchange levels, the degree of genetic instability as well as DNA repair by homologous recombination differed among cell lines. CDDP and 20 μM APG cotreatment exhibited a synergistic genotoxic effect on Hep3B cells and a less than additive effect on HepG2 and Huh7 cells. Cell cycle delays were noticed during the first mitotic division in Hep3B and Huh7 cells and the second mitotic division in HepG2 cells. CDDP and CDDP + APG treatments reduced the clonogenic capacity of all cell lines; however, there was a discordance in drug sensitivity compared with the MMT assay. Furthermore, a senescence-like phenotype was induced, especially in Hep3B and Huh7 cells. Unlike CDDP monotherapy, the combined treatment exhibited a significant anti-invasive and anti-migratory action in all cancer cell lines. The fact that the three liver cancer cell lines responded differently, yet positively, to CDDP + APG cotreatment could be attributed to variations they present in gene expression. Complex mechanisms seem to influence cellular responses and cell fate.

Anti-Inflammatory Potential Exhibited by Amomum subulatum Fruits Mitigates Experimentally Induced Acute and Chronic Inflammation in Mice: Evaluation of Antioxidant Parameters, Pro-Inflammatory Mediators and HO-1 Pathway

OBJECTIVE

Conventional anti-inflammatory drugs are associated with serious adverse effects which bring about an ever-increasing demand to supersede them with natural and safe anti-inflammatory agents. Hence, the prime objective of this study was to evaluate the anti- inflammatory potential of an underutilized culinary spice "Amomum subulatum".

METHODS

To assess anti-inflammatory activity of MEAS, acute and chronic inflammation studies were carried out in carrageenan and formalin induced mice paw edema models respectively. Paw volume was measured by vernier caliper. Status of antioxidant enzymes and oxidative stress markers were determined in paw tissue homogenates following standard protocols. Histopathology and immunohistochemistry analysis of paw tissue samples were also performed. Levels of proinflammatory cytokines in serum were quantified by ELISA. Effect of MEAS on vascular permeability was evaluated by evans blue dye extravasation assay. Involvement of heme oxygenase (HO)-1 pathway in anti-inflammatory action of MEAS was investigated by pretreating mice with zinc protoporphyrin (ZnPP) IX, a specific inhibitor of HO-1.

RESULTS

MEAS administration significantly reduced paw edema, as evidenced by paw volume measurement and histopathology analysis. Additionally, pretreatment with MEAS markedly reduced vascular permeability, serum proinflammatory cytokine levels, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Further, the anti-inflammatory mechanism of MEAS showed the involvement of HO-1 pathway when HO-1 was inhibited by ZnPPIX.

CONCLUSION

Our results manifested strong anti-inflammatory activity of MEAS, suggesting its potential use as a therapeutic alternative for treating inflammatory disorders.

Structural basis for producing selective MAP2K7 inhibitors

Mitogen-activated protein kinase kinase 7 (MAP2K7) in the c-Jun N-terminal kinase signal cascade is an attractive drug target for a variety of diseases. The selectivity of MAP2K7 inhibitors against off-target kinases is a major barrier in drug development. We report a crystal structure of MAP2K7 complexed with a potent covalent inhibitor bearing an acrylamide moiety as an electrophile, which discloses a structural basis for producing selective and potent MAP2K7 inhibitors.

Alpinetin prevents inflammatory responses in OVA-induced allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways in mice

Allergic asthma is the most common type of asthma which characterized by inflammatory responses of the airways. Alpinetin, a flavonoid compound derived from the ginger family of medicinal herbs, possesses various biological properties including anti-inflammatory, anti-oxidant and other medical effects. In this study, we aimed to evaluate the effects of alpinetin on OVA-induced allergic asthma, and further to examine its molecular mechanisms underlying these processes in vivo and in vitro. Mice were sensitized and challenged with OVA to build allergic asthma model in vivo. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells analysis and lung tissues were examined for histopathological examination. The levels of IL-5, IL-13, IL-4, IgE, TNF-α, IL-6 and IL-1β were determined by the respective ELISA kits. The PI3K/AKT/NF-κB and HO-1 signaling pathways were examined by western blot analysis. The results showed that alpinetin significantly ameliorated OVA-induced pathologic changes of lungs, such as decreasing massive inflammatory cell infiltration and mucus hypersecretion, and reduced the number of inflammatory cells in BALF. Alpinetin also decreased the OVA-induced levels of IL-4, IL-5, IL-13 and IgE. Furthermore, alpinetin inhibited OVA-induced phosphorylation of p65, IκB, PI3K and AKT, and the activity of HO-1 in vivo. More importantly, these anti-inflammatory effects and molecular mechanisms of alpinetin has also been confirmed in LPS-stimulated RAW 264.7 macrophages in vitro. In conclusion, above results indicate that alpinetin exhibites a potent anti-inflammatory activity in allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways, which would be used as a promising therapy agent for allergic asthma.

The role of medicinal products in the treatment of inflammatory bowel diseases (IBD) through inhibition of TLR4/NF-kappaB pathway

Inflammatory bowel disease (IBD) is a lifelong and recurrent disease of the gastrointestinal tract that afflicts many people in the world. Growing evidence has currently indicated that dysfunction of immune system, particularly toll-like receptors 4 (TLR4) signaling pathway dysfunction plays a pivotal part in the pathogenesis of IBD. TLR4 signaling is involved both in the pathogenesis and in the efficacy of treatment of IBD. There are some medicinal products and herbal medicines, which their role in the treatment of IBD through modulation of TLR4 signaling has been implicated. The purpose of this review article is to summarize those medicinal products and herbal medicines.

Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products

Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.

Modulation of Aquaporins by Dietary Patterns and Plant Bioactive Compounds

Healthful dietary patterns and bioactive compounds supplementation can be adopted as simple and easy intervention to prevent, attenuate or cure clinical disorders, especially when it comes to degenerative and chronic diseases. In the recent years, a growing body of evidence indicates Aquaporins (AQPs), a family of membrane channel proteins widely expressed in the human body, among the targets underlying the beneficial action played by some food nutrients and phytochemical compounds. Here, we provide an overview of what is known regarding the AQP modulation exerted by healthful dietary patterns and plant polyphenols.

Alpinetin Inhibits Oral Squamous Cell Carcinoma Proliferation via miR-211-5p Upregulation and Notch Pathway Deactivation

Background: The effect of alpinetin (ALP) on miR-211-5p level and function in oral squamous cell carcinoma (OSCC) remains unclear.Materials and methods: Human OSCC cell lines (CAL-27 and TCA-8113) and a mouse xenograft model with subcutaneously injected TCA-8113 cells were used. Effect of ALP treatment on cell viability, cell cycle distributions, and p-p53, p21, c-PARP, cyclin D1, NICD, HES1, and miR-211-5p expression levels was analyzed. Influence of ALP on tumor volume and weight was determined.Results: ALP treatment (at doses 400 and 500 µM) significantly decreased the viability of CAL-27 and TCA-8113 cells (P < 0.05). It upregulated the number of cells in G1 phase and miR-211-5p expression, increased p-p53, p21, and c-PARP levels, and decreased cyclin D1 levels. Furthermore, miR-211-5p mimic treatment increased the number of cells in G1 phase, and p53, p21, and c-PARP levels, and decreased cyclin D1 levels. Contrasting effects were observed under anti-miR-211-5p treatment. ALP downregulated NICD and HES1, whereas anti-miR-211-5p increased NICD and HES1 expression. ALP effects were alleviated in both cell lines under Jagged-1 overexpression plasmid treatment. Finally, ALP inhibited tumor growth and increased miR-211-5p expression in vivo.Conclusion: ALP-induced miR-211-5p upregulation and Notch pathway deactivation may be involved in its anti-proliferative effects in OSCC.

A sensitive resonance Rayleigh light scattering method for alpinetin using gold nanorods probes

A sensitive resonance Rayleigh light scattering (RLS) assay for alpinetin was developed based on alpinetin-modified gold nanorods (AuNRs). Alpinetin could interact with AuNRs and formed a new assembly by electrostatic attraction. In pH 7.4 Tris-HCl buffer solution, the assembly of alpinetin-AuNRs showed a sensitive RLS signal. Under optimum conditions, the magnitude of enhanced RLS intensity (ΔI_RLS ) was proportional to the concentration of alpinetin over the range 0.027-3.24 μg ml^-1 , with a detection limit of 1.79 ng ml^-1 (by 3σ). The developed RLS method was successfully applied to the detection of alpinetin in real or synthesized samples. Alpinetin recoveries were 90.4-108.7% with an RSD of 0.82-2.9% (n = 5) for Alpinia katsumadai samples, and 95.1-103.7% with an RSD of 0.28-3.9% (n = 5) for synthesized samples. The results showed that this new approach was convenient, reliable and sensitive.

Alpinetin inhibits proliferation and migration of ovarian cancer cells via suppression of STAT3 signaling

Natural bioactive components are increasingly being applied in cancer research. Alpinetin is a type of natural flavonoid primarily derived from Alpinia katsumadai Hayata, which exhibits anti‑bacterial and anti‑inflammatory properties. Therefore, it may possess anticancer potential and be employed therapeutically for different diseases. The aim of the present study was to investigate the anticancer effects of alpinetin on the SKOV3 ovarian cancer cell line. The effect of alpinetin treatment on SKOV3 cell proliferation, apoptosis, spheroid and colony formation were measured using Cell Counting kit‑8, cell apoptosis, 3D spheroid and colony formation assays, respectively. Analysis of the cell cycle was performed using flow cytometry. Western blot analysis was used to determine the protein expression levels of B‑cell lymphoma (Bcl)‑2, Bcl‑2‑associated X protein, cleaved caspase‑3, cleaved poly (ADP‑ribose) polymerase (PARP), cyclin D1, cyclin‑dependent kinase (CDK) 4, CDK6, signal transducer and activator of transcription (STAT) 3, phosphorylated (p)‑STAT3, c‑myc, survivin, tissue inhibitor of metalloproteinase (TIMP)‑1, TIMP‑2, matrix metalloproteinase (MMP)‑2 and MMP‑9. In addition, a wound healing assay was used to determine cancer cell migration. The results revealed alpinetin suppressed cell viability and induced apoptosis of SKOV3 cells in a dose‑ and time‑dependent manner, and cells were arrested in the G1 phase. Alpinetin treatment upregulated protein expression levels of Bax, cleaved caspase‑3 and PARP, and downregulated protein expression levels of Bcl‑2, cyclin D1, CDK4 and CDK6. Alpinetin also inhibited cell migration, through increased protein expression levels of TIMP‑1 and TIMP‑2, and decreased protein expression levels of MMP‑2 and MMP‑9. Alpinetin also significantly suppressed colony and spheroid formation by SKOV3 cells. In addition, the STAT3 pathway was suppressed as demonstrated by downregulation of p‑STAT3 and reduced expression of downstream factors, including c‑myc and survivin. Overall, these results indicated that alpinetin may have anticancer effects on human ovarian cancer by inhibiting the STAT3 signaling pathway.

Quantification and pharmacokinetics of alpinetin in rat plasma by UHPLC-MS/MS using protein precipitation coupled with dilution approach to eliminate matrix effects

Alpinetin, a bioactive flavonoid, has attracted great attention due to its diverse therapeutic effects, namely anti-oxidant, anti-tumor and anti-inflammatory effects with low systemic toxicity. Various determination methods have been developed in quality control and plant chemistry areas. However, quantification and pharmacokinetics of alpinetin in biological matrix have not been studied. In the present research, a sensitive, efficient and reliable ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of alpinetin in rat plasma was developed and validated. Plasma samples were processed with protein precipitation (PP) followed by a 5-fold acetonitrile/water (50:50, v/v) dilution to significantly decrease matrix effect which exited in one step PP method. Determination of alpinetin was conducted using positive electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode. Results demonstrated that the method was precise (3.3%-12.3%), accurate (-5.8% to 10.8%) and linear in the range of 1-1000 ng/mL. The new developed method was subsequently applied to a pharmacokinetic research of alpinetin following oral and intravenous dosing to healthy Sprague-Dawley rats. Alpinetin was demonstrated rapid absorption after oral administration with an absolute bioavailability of ∼15.1% and extensive distribution after dosing.

The P38α rs3804451 Variant Predicts Chemotherapy Response and Survival of Patients with Non-Small Cell Lung Cancer Treated with Platinum-Based Chemotherapy

The JNK and P38α pathways play an important role in the sensitivity and outcomes of chemotherapy. We hypothesize that functional single nucleotide polymorphisms (SNPs) of genes of these pathways modulate outcomes of patients with advanced non-small cell lung cancer (NSCLC) treated with first-line platinum-based chemotherapy (PBC). We selectively genotyped 11 independent, potentially functional SNPs of 9 genes in the JNK and P38α pathways first in a discovery group of 355 patients with advanced NSCLC treated with PBC, and we evaluated their associations with progression-free survival (PFS) and overall survival (OS) by Cox proportional hazards regression analysis. Then, resultant significant SNPs were further validated in a replication group of 355 patients. In both discovery and validation groups as well as their combined analysis, the MAPK14 rs3804451GA/AA genotypes showed a strong association with a reduced PFS (adjusted hazards ratio [HR]=1.39; 95% confidence interval [CI]=1.16-1.66; P=.0003) and OS (adjusted HR=1.41; 95% CI=1.11-1.80; P=.005) compared with the wild-type GG genotype. In contrast, patients with or without the MAPK14 rs3804451A allele had no significant difference in OS in response to tyrosine-kinase inhibitor treatment (adjusted HR=0.86; 95% CI=0.56-1.33; P=.505). The present study provides evidence that the MAPK14 rs3804451 G>A variant may modulate survival outcomes in patients with advanced NSCLC treated with PBC. Larger studies of additional patient populations are needed to validate our findings.

Alpinetin attenuates inflammatory responses by suppressing TLR4 and NLRP3 signaling pathways in DSS-induced acute colitis

Alpinetin, a composition of Alpinia katsumadai Hayata, has been reported to have a number of biological properties, such as antibacterial, antitumor and other important therapeutic activities. However, the effect of alpinetin on inflammatory bowel disease (IBD) has not yet been reported. The purpose of this study was to investigate the anti-inflammatory effect and mechanism of alpinetin on dextran sulfate sodium (DSS)-induced colitis in mice. In vivo, DSS-induced mice colitis model was established by giving mice drinking water containing 5% (w/v) DSS for 7 days. Alpinetin (25, 50 and 100 mg/kg) were administered once a day by intraperitoneal injection 3 days before DSS treatment. In vitro, phorbol myristate acetate (PMA)-differentiated monocytic THP-1 macrophages were treated with alpinetin and stimulated by lipopolysaccharide (LPS). The results showed that alpinetin significantly attenuated diarrhea, colonic shortening, histological injury, myeloperoxidase (MPO) activity and the expressions of tumor necrosis factor (TNF-α) and interleukin (IL-1β) production in mice. In vitro, alpinetin markedly inhibited LPS-induced TNF-α and IL-1β production, as well as Toll-like receptor 4 (TLR4) mediated nuclear transcription factor-kappaB (NF-κB) and NOD-like receptor protein 3 (NLRP3) inflammasome activation. In conclusion, this study demonstrated that alpinetin had protective effects on DSS-induced colitis and may be a promising therapeutic reagent for colitis treatment.

A crucial role of Cys218 in configuring an unprecedented auto-inhibition form of MAP2K7

Mitogen-activated protein kinase kinase 7 (MAP2K7) is an indispensable kinase of the c-Jun N-terminal kinase signal cascade and is rigorously regulated via phosphorylation. To investigate the regulatory mechanism of the inactive non-phosphorylated state of MAP2K7, the crystal structures of the wild-type and C218S mutant were solved. The wild-type apo-structure revealed an unprecedented auto-inhibition form that occluded the ATP site. This closed form was configured by the n-σ* interaction of Cys218, a non-conserved residue among the MAP2K family kinases, with Gly145 in the glycine-rich loop. The interaction was unaltered in the presence of an ATP analog, whereas the C218S mutation precluded the closed configuration. These structural insights are potentially valuable for drug discovery of highly selective MAP2K7 inhibitors.

Solanine-induced reactive oxygen species inhibit the growth of human hepatocellular carcinoma HepG2 cells

The aim of the present study was to investigate the effect of solanine on promoting human hepatocellular carcinoma HepG2 cells to produce reactive oxygen species (ROS), and the molecular mechanisms leading to tumor cell apoptosis. Solanine was administered to HepG2 cells in vitro. A selection of probes targeting various cellular localizations of ROS were used to detect ROS expression using flow cytometry. The expression levels of apoptosis-associated proteins, including apoptosis signal-regulating kinase 1 (ASK1) and thioredoxin binding protein 2 (TBP-2), and proliferation-associated proteins, including histone deacetylase 1 (HDAC1), were detected using western blotting. The percentage of cells undergoing apoptosis was measured using an Annexin V-fluorescein isothiocyanate/propidium iodide assay, and cell morphology was examined using Wright's stain followed by inverted microscopy analysis. ROS detection probes 2',7'-dichlorofluorescin diacetate and dihydrorhodamine 123 identified that abundant ROS, including hydroxyl radical (OH^-) and hydrogen peroxide (H₂O₂), were produced in the cytoplasm and mitochondria of the solanine-treated HepG2 cells compared with the control cells (P<0.05). Superoxide anion specific probes dihydroethidium and MitoSOX™ demonstrated that there were no significant alterations in the HepG2 cells following solanine treatment compared with the control cells (P>0.05). Western blotting results revealed that solanine upregulated the expression levels of ASK1 and TBP-2 and enhanced their kinase activities, whereas solanine decreased the expression level of the proliferation-associated protein, HDAC1. The cell apoptotic rate was significantly increased (P<0.0001) in the solanine-treated HepG2 cells compared with the control cells. (P<0.05). Overall, the study indicated that solanine induces HepG2 cells to produce ROS, mainly OH^- and H₂O₂, in a mitochondria-dependent and -independent manner. In addition, solanine stimulates the expression of ASK1 and TBP-2, and their kinase activities, but inhibits the expression of proliferation-associated proteins, such as HDAC1, thus contributing to HepG2 cell apoptosis.

Effects of Serial Passage on the Characteristics and Cardiac and Neural Differentiation of Human Umbilical Cord Wharton's Jelly-Derived Mesenchymal Stem Cells

Background and Objective. It is important to guarantee the quality of stem cells. Serial passage is the main approach to expand stem cells. This study evaluated effects of serial passage on the biological characteristics of human umbilical cord Wharton's jelly-derived MSCs (WJ MSCs). Methods. Biological properties of WJ MSCs in the early (less than 10 passages, P10), middle (P11–20), and late (more than P20) phases including cell proliferation, cell cycle, phenotype, senescence, oncogene expression, stemness marker expression, and differentiation capacity were evaluated using flow cytometry, real-time PCR, immunocytofluorescence, and western blot. Results. It was found that there were no significant differences in cell proliferation, cell cycle, phenotype, and stemness marker expression in different phases. However, the expression of senescence-related gene, p21, and oncogene, c-Myc, was significantly upregulated in the late phase, which had close relations with the obviously increased cell senescence. Moreover, cardiac differentiation capability of WJ MSCs decreased whereas the propensity for neural differentiation increased significantly in the middle phase. Conclusions. This study reveals that WJ MSCs in the early and middle phases are relatively stable, and effect of serial passage on the lineage-specific differentiation should be considered carefully.

Alpinetin inhibits lung cancer progression and elevates sensitization drug-resistant lung cancer cells to cis-diammined dichloridoplatium

OBJECTIVE

Alpinetin is a novel flavonoid that has demonstrated potent antitumor activity in previous studies. However, the efficacy and mechanism of alpinetin in treating lung cancer have not been determined.

METHODS

We evaluated the impact of different doses and durations of alpinetin treatment on the cell proliferation, the apoptosis of lung cancer cells, as well as the drug-resistant lung cancer cells.

RESULTS

This study showed that the alpinetin inhibited the cell proliferation, enhanced the apoptosis, and inhibited the PI3K/Akt signaling in lung cancer cells. Moreover, alpinetin significantly increased the sensitivity of drug-resistant lung cancer cells to the chemotherapeutic effect of cis-diammined dichloridoplatium. Taken together, this study demonstrated that alpinetin significantly suppressed the development of human lung cancer possibly by influencing mitochondria and the PI3K/Akt signaling pathway and sensitized drug-resistant lung cancer cells.

CONCLUSION

Alpinetin may be used as a potential compound for combinatorial therapy or as a complement to other chemotherapeutic agents when multiple lines of treatments have failed to reduce lung cancer.

Silencing of the ABCC4 gene by RNA interference reverses multidrug resistance in human gastric cancer

The identification of genes associated with recurrent drug resistance in gastric cancer and the elucidation of the underlying molecular mechanisms associated with recurrent drug resistance in gastric cancer are important for the effective treatment and prognosis of this cancer. Variations in the expression level of the ATP-binding cassette subfamily C member 4 (ABCC4) gene are correlated with the recurrence, development and chemotherapeutic susceptibility of various types of cancers. In the present study, we demonstrated that the ABCC4 gene was highly expressed in multiple types of gastric cancer cells, and ABCC4 expression was even more prominent in the drug-resistant gastric cancer cells. Conversely, in normal gastric mucosal cells, ABCC4 expression was very low or undetectable. We used RNA interference to decrease the expression of ABCC4 in drug-resistant gastric cancer cells, which resulted in an increase in apoptosis and cell cycle arrest in the G1 phase. In addition, we found that ABCC4 knockdown in 5-fluorouracil (5-FU)-resistant cancer cells restored 5-FU sensitivity, resulting in the inhibition of cell proliferation and tumour growth in nude mice. Our results showed that inhibition of ABCC4 gene expression can inhibit the proliferation of multidrug-resistant gastric cancer cells and can enhance gastric cancer cell sensitivity to chemotherapeutic drugs.

5Z-7-Oxozeaenol covalently binds to MAP2K7 at Cys218 in an unprecedented manner

5Z-7-Oxozeaenol (5Z7O) is a covalent bonding inhibitor against the several protein kinases (e.g., ERK2 and TAK1) that possess a free cysteine at the gatekeeper-2 position. In addition to this cysteine, MAP2K7 has three other cysteine residues that are candidate for covalent bonding by the inhibitor 5Z7O. The crystal structure of the MAP2K7/5Z7O complex revealed that the inhibitor binds to MAP2K7 at a cysteine residue located at the end of the hinge region and not at the gatekeeper-2 residue. The structural insights into the interaction of 5Z7O with MAP2K7 should aid the development of 5Z7O derivatives with improved potency and selectivity.

Cytotoxicity and modes of action of 4'-hydroxy-2',6'-dimethoxychalcone and other flavonoids toward drug-sensitive and multidrug-resistant cancer cell lines

INTRODUCTION

Resistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4'-hydroxy-2',6'-dimethoxychalcone (1), cardamomin (2), 2',4'-dihydroxy-3',6'-dimethoxychalcone (3)], and four flavanones [(S)-(-)-pinostrobin (4), (S)-(-)-onysilin (5) and alpinetin (6)] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types.

METHODS

The resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometry for the mechanistic studies of the most active molecule (1).

RESULTS

IC50 values in a range of 2.54 μM against CEM/ADR5000 leukemia cells to 58.63 μM toward hepatocarcinoma HepG2 cells were obtained with 1. The lowest IC50 values of 8.59 μM for 2 and 10.67 μM for 3 were found against CCRF-CEM cells leukemia cells, whilst the corresponding values were above 80 μM for 4 and 6. P-glycoprotein-expressing and multidrug-resistant CEM/ADR5000 cells were much more sensitive toward compound 1 than toward doxorubicin and low cross-resistance or even collateral sensitivity was observed in other drug-resistent cell lines to this compound. Normal liver AML12 cells were more resistant to the studied compounds than HepG2 liver cancer cells, indicating tumor specificity at least to some extent. Compound 1 arrested the cell cycle between Go/G1 phase, strongly induced apoptosis via disrupted mitochondrial membrane potential (MMP) and increased production of reactive oxygen species (ROS) in the studied leukemia cell line.

CONCLUSIONS

Chalcone 1 was the best tested cytotoxic molecule and further studies will be performed in order to envisage its possible use in the fight against multifactorial resistant cancer cells.

The chalcones cardamonin and flavokawain B inhibit the differentiation of preadipocytes to adipocytes by activating ERK

AIM

We searched for polyphenols capable of inhibiting the lipid accumulation in 3T3-L1 cells, and investigated the mechanisms of two effective chalcones cardamonin and flavokawain B on differentiation of preadipocytes.

METHOD AND RESULTS

We treated 3T3-L1 cells with a panel of 46 polyphenols and measured intracellular lipid accumulation by Sudan II staining. Four of them, including cardamonin and flavokawain B, inhibited lipid accumulation. In the further study, cardamonin and flavokawain B inhibited lipid accumulation by downregulating the expression of CCAAT/enhancer binding protein (C/EBP)-β, C/EBPα, and peroxisome proliferator-activated receptor-γ (PPARγ) at both mRNA and protein levels. Cardamonin and flavokawain B also increased phosphorylation of extracellular signal-regulated kinase (ERK) in the early phase of adipocyte differentiation. PD98059, an ERK inhibitor, restored C/EBPβ, PPARγ expression and intracellular lipid accumulation in adipocytes. Moreover, cardamonin and flavokawain B also modulated the secretion of C-reactive protein, dipeptidyl peptidase IV, interleukin-6, tumor necrosis factor-α and fibroblast growth factor-21 in mature adipocytes.

CONCLUSIONS

These results indicate that ERK activation and consequent downregulation of adipocyte-specific transcription factors are involved in the inhibitory effects of the chalcones cardamonin and flavokawain B on adipocyte differentiation. Moreover, cardamonin and flavokawain B are able to modulate secretion of adipokines in mature adipocytes.

In vivo and in vitro inhibition of human liver cancer progress by downregulation of the μ-opioid receptor and relevant mechanisms

Opiates have long been used as analgesics to relieve pain associated with various medical conditions. μ-opioid receptor (MOR) is the main member of the opioid receptor super-family and the excitation or overexpression of MOR promotes the proliferation of many kinds of tumor cells. It was found in our previous studies that MOR was highly expressed in the tissue and cells of human liver cancer. However, the impact of MOR on the progress of human liver cancer remains unknown. The purpose of this study is to investigate the impact of MOR downregulation on the progress of human liver cancer and the mechanisms involved. RNA interfering or specific inhibitor was administered to downregulate the MOR in human hepato-cellular carcinoma cells and it was found that the proliferation of hepatocellular carcinoma cells was significantly inhibited with the increase of the apoptotic rate, while the cell cycle was blocked in G0/G1 phase and the tumor growth in the mice was retarded. In addition, downregulation of MOR resulted in the increase of phosphorylation of the MKK7 expression and JNK activation. On the contrary, blockade of MKK7 pathway can reverse the antitumor role of MOR. In summary, downregulation of MOR is able to inhibit both in vivo and in vitro human liver cancer progress and it shows potential to be used in cancer therapy.

Alpinetin attenuates inflammatory responses by interfering toll-like receptor 4/nuclear factor kappa B signaling pathway in lipopolysaccharide-induced mastitis in mice

Alpinetin, a novel plant flavonoid derived from Alpinia katsumadai Hayata, has been reported to exhibit anti-inflammatory properties. However, the effect of alpinetin on mastitis has not been investigated. The aim of this study was to investigate the protective effect of alpinetin against lipopolysaccharide (LPS)-induced mastitis and to clarify the possible mechanism. In the present study, primary mouse mammary epithelial cells and an LPS-induced mouse mastitis model were used to investigate the effect of alpinetin on mastitis and the possible mechanism. In vivo, we observed that alpinetin significantly attenuated the infiltration of neutrophilic granulocytes, and the activation of myeloperoxidase; down-regulated the level of pro-inflammatory cytokines, including TNF-α, IL-1β and IL-6; inhibited the phosphorylation of IκB-α, NF-κB p65 and the expression of TLR4, caused by LPS. In vitro, we also observed that alpinetin inhibited the expression of TLR4 and the production of TNF-α, IL-1β and IL-6 in LPS-stimulated primary mouse mammary epithelial cells. However, alpinetin could not inhibit the production of IL-1β and IL-6 in TNF-α-stimulated primary mouse mammary epithelial cells. In conclusion, our results suggest that the anti-inflammatory effects of alpinetin against LPS-induced mastitis may be due to its ability to inhibit TLR4-mediated NF-κB signaling pathways. Alpinetin may be a promising potential therapeutic reagent for mastitis treatment.

RNA interference-mediated USP22 gene silencing promotes human brain glioma apoptosis and induces cell cycle arrest

Ubiquitin-specific protease 22 (USP22) is a novel tumor stem cell marker that plays a key role in tumorigenesis and cell cycle progression. However, the effect of silencing the USP22 gene on human brain glioma cell growth is not well understood. In the present study, high gene expression of USP22 was identified in human brain glioma cells. In addition, RNA interference technology was used to silence USP22 gene expression in human brain glioma cells. Silencing the USP22 gene was found to effectively inhibit proliferation of human brain glioma cells, resulting in cell apoptosis and cell cycle arrest at the G₂/M phase. USP22 silencing was also found to lead to reduced expression of cell cycle proteins, including CDK1, CDK2 and CyclinB1. In summary, in this study the USP22 gene was demonstrated to play a key regulatory role in the growth of human brain glioma cells by affecting progression of apoptosis and the cell cycle.