Qinglong Guo

China Pharmaceutical University, Nan-ching-hsü, Jiangxi Sheng, China

Are you Qinglong Guo?

Claim your profile

Publications (104)323.23 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Excess or inappropriate angiogenesis occurs in the pathogenesis process of many diseases, such as cancer, wound healing and eye disease, especially angiogenesis stimulated by inflammatory factors contributes to the development of inflammation and cancer. In this study, we investigated the inhibitory effect of LL202, a newly synthesized flavonoid, on LPS-induced angiogenesis and further probed the potential molecular mechanisms by detecting MAPK and NF-κB pathways. We found that LL202 inhibited LPS-induced migration, tube formation of human umbilical vein endothelial cells (HUVECs), and microvessel sprouting from rat aotric ring in vivo. The result of matrigel plug assay and chicken chorioallantoic membrane (CAM) model also revealed that LL202 could inhibit LPS-induced angiogensis in vivo. Western Blot analysis indicated that LL202 could inhibit the expression of LPS acceptor toll-like receptor 4 (TLR4) and its downstream protein kinases, including the phosphorylation of JNK, p38, ERK, IKK and IκBα. Moreover, LL202 inhibited the nuclear translocation of NF-κB and its binding to DNA. Accordingly, the expression of vascular endothelial growth factor (VEGF) was down-regulated at the level of gene transcription, which is a crucial mediator in angiogenesis. Taken together, LL202 could suppress LPS-induced angiogenesis with the intervention of LPS/TLR4 signaling.
    RSC Advances 10/2014; · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Constitutive NF-E2-related factor 2(Nrf2) activation has been recently reported to play a pivotal role in enhancing cell survival and resistance to anticancer drugs in many tumors. Previously, much effort has been devoted to the investigation of blocking Nrf2 function in cultured cells and cancer tissues, but few research has been undertaken to evaluate the precise mechanism of flavonoids-induced sensitivity by inhibiting Nrf2. In this study, we investaged the reversal effect of Wogonin, a flavonoid isolated from the root of Scutellaria baicalensis Georgi, in resistant human myelogenous leukemia. Data indicated that Wogonin had strong reversal potency by inhibiting functional activity and expression of MRP1 at both protein and mRNA in adriamycin(ADR)-induced resistant human myelogenous leukemia K562/A02 cells. Consequently, the inhibition of MRP1 by Wogonin was dependent on Nrf2 through the decreased binding ability of Nrf2 to antioxidant response element(ARE). Further research revealed Wogonin modulated Nrf2 through the reduction of Nrf2mRNA at transcriptional processes rather than RNA degradation, which is regulated by the PI3K/Akt pathway. Moreover, DNA-PKcs was found to be involved in the Wogonin-induced downregulation of Nrf2 mRNA at transcriptional levels. In summary, these results clearly demonstrated the effectiveness of using Wogonin via inhibiting Nrf2 to combat chemoresistance and suggested that Wogonin can be developed into an efficient natural sensitizer for resistant human myelogenous leukemia.
    Biochemical Pharmacology. 09/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Autophagy is a tightly-regulated catabolic pathway involving degradation of cellular proteins, cytoplasm and organelles. Recent evidence suggests that autophagy plays a potential role in cell death as a tumor suppressor and that its induction especially in combination with apoptosis could be beneficial. It remains unclear if all cancer cells behave the same mechanism when autophagy is induced. Although mammalian target of rapamycin (mTOR) is well known as a negative regulator of autophagy, the relationship between signal transducer and activator of transcription 3 (STAT3) and autophagy has not yet been investigated. Oroxylin A, a natural mono-flavonoid extracted from Scutellariae radix, is a promising therapeutic agent for treating multiple cancers. Here we investigated the mechanism underlying the effect of oroxylin A on malignant glioma cells. We showed that oroxylin A inhibited the proliferation of malignant glioma cells by inducing autophagy in a dose- and time-dependent manner. Oroxylin A treatment inhibits the AKT and ERK activation and the downstream phosphorylation level of mTOR and STAT3. In addition, oroxylin A treatment decreases the expression of Notch-1 and myeloid cell leukemia-1 (Mcl-1) but upregulates Beclin 1, the key autophagy-related protein. 3-MA (autophagy inhibitor) or knockdown of Beclin 1 partially can rescue cells from oroxylin A-induced autophagic cell death. In contrast, knockdown of STAT3 aggravates oroxylin A-induced autophagic cell death. Our data reveal an important role of autophagy in enhancing cell death induced by oroxylin A and conclude that oroxylin A exerts anti-malignant glioma proficiency by inducing autophagy via the ERK/AKT-mTOR-STAT3-Notch signaling cascade. © 2014 Wiley Periodicals, Inc.
    Molecular Carcinogenesis 09/2014; · 4.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Oroxylin A is a flavonoid extracted from the root of Scutellaria baicalensis Georgi. Our previous research demonstrated that oroxylin A have various anti-tumor effects including apoptosis, cell cycle arrest, drug-resistant reversion and others. This paper explores the mechanism how oroxylin A induce apoptosis by regulating uncoupling protein 2 (UCP2) in human colon cancer cells. We found that the inhibition of UCP2 by UCP2 siRNA significantly increased the sensitivity of cells to drugs, reactive oxygen species (ROS) generation and the opening of mitochondrial permeability transition pore (MPTP) of CaCo-2 cells. We also found that UCP2 inhibition could lead to ROS-mediated MPTP activation. Furthermore, we demonstrated that oroxylin A triggered MPTP-dependent pro-apoptotic protein release from mitochondria to matrix and then induced apoptotic cascade by inhibiting UCP2. Intriguingly, the inhibition of UCP2 by oroxylin A was able to block Bcl-2 translocation to the mitochondria, keeping MPTP at open-state. In conclusion, we have demonstrate that UCP2 play a key role in mitochondrial apoptotic pathway; UCP2's inhibition by oroxylin A triggers the MPTP opening, and promotes the apoptosis in CaCo-2 cells. J. Cell. Physiol. © 2014 Wiley Periodicals, Inc.
    Journal of Cellular Physiology 09/2014; · 4.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Production of IL-6 constituted the major cause of death in the ATRA trial called retinoic acid syndrome (RAS). LAP and LIP are active and inactive isoforms of C/EBPβ, respectively. Inactive LIP dimerized with LAP to eliminate its activity. Following treatment with ATRA, CHOP expression was increased and dimerized with LIP more preferentially than LAP to rescue function of LAP. Oroxylin A has been reported to activate CHOP, a key mediator of unfolded protein response (UPR) pathway, and resulted in apoptosis. Interestingly, we found that low concentration of oroxylin A (≦40μM) showed no apoptosis effect on NB4 and HL-60 cells and decreased the CHOP protein level via promoting its degradation. MG132 was utilized to conform the effect of oroxylin A on degrading CHOP. Our results showed that oroxylin A decreased the level of IL-6 secretion of NB4 cells with or without ATRA treatment while the effect was eliminated by C/EBPβ siRNA. We conclude that oroxylin A possessed abilities of inhibiting the ATRA-induced IL-6 production via modulation of LAP/LIP/CHOP in leukemia cell lines, which could providing a therapeutic strategy for RAS.
    Gene 09/2014; · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wogonin, a flavonoid derived from Scutellaria baicalensis Georgi, has been demonstrated to be highly effective in treating hematologic malignancies. In this study, we investigated the anticancer effects of wogonin on K562 cells, K562 imatinib-resistant cells, and primary patient-derived CML cells. Wogonin up-regulated transcription factor GATA-1 and enhanced binding between GATA-1 and FOG-1, thereby increasing expression of erythroid-differentiation genes. Wogonin also up-regulated the expression of p21 and induced cell cycle arrest. Studies employing benzidine staining and analyses of cell surface markers glycophorin A (GPA) and CD71 indicated that wogonin promoted differentiation of K562, imatinib-resistant K562, and primary patient-derived CML cells. Wogonin also enhanced binding between GATA-1 and MEK, resulting in inhibition of the growth of CML cells. Additionally, in vivo studies showed that wogonin decreased the number of CML cells and prolonged survival of NOD/SCID mice injected with K562 and imatinib-resistant K562 cells. These data suggested that wogonin induces cycle arrest and erythroid differentiation in vitro and inhibits proliferation in vivo.
    Oncotarget 08/2014; · 6.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wogonin, a natural monoflavonoid extracted from Scutellariae radix, has been reported for its ability of inhibiting tumor angiogenesis. In this study, we assessed the effect of wogonin on angiogenesis induced by low level of H2O2 (10 μM) in human umbilical vein endothelial cells (HUVECs). Wogonin suppressed H2O2-induced migration and tube formation of HUVECs as well as microvessle sprouting from rat aortic rings in vitro. Meanwhile, wogonin suppressed vessels growth in chicken chorioallantoic membrane (CAM) model in vivo. Mechanistic studies showed that wogonin suppressed H2O2-activated PI3K/Akt pathway and reduced the expression of vascular endothelial growth factor (VEGF) up-regulated by H2O2 in both protein and mRNA levels. In addition, wogonin also inhibited nuclear translocation of NF-κB, and decreased the binding ability of NF-κB with exogenous consensus DNA oligonucleotide. Then we further invesitigated the effect of wogonin on over-activated PI3K/Akt pathway by insulin-like growth factor-1 (IGF-1) and H2O2. We found wogonin suppressed phosphorylation of Akt, up-regulation of VEGF and angiogenesis in vitro which was further induced by IGF-1 and H2O2. Moreover, in NF-κB overexpressed HUVECs, wogonin could also reduce the expression of VEGF and inhibited the migration and tube formation. Taken together, these results suggested that wogonin was potential in inhibiting H2O2-induced angiogenesis in vitro and in vivo via suppressing PI3K/Akt pathway and NF-κB signaling.
    Vascular Pharmacology 08/2014; · 3.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was aimed at investigating the reversal effect of oroxylin A, a naturally bioactive monoflavonoid separated and purified from S. baicalensis Georgi, in human chronic myeloid leukemia (CML) and the underlying mechanisms. The results showed that CXCL12 could enhance the resistance of K562 cells to adriamycin (ADM) by increasing the expression of CXCR4, up-regulating the downstream PI3K/Akt pathway, and promoting translocation of NF-κB dimers into nucleus and subsequently decreasing the expression of apoptosis-related proteins in K562 cells. And we found that ADM resistance was partially reversed by CXCR4 siRNA transfection. Moreover, the sensitivity enhancement of oroxylin A was demonstrated by decreasing the expression of CXCR4 at both protein and mRNA levels, via PI3K/Akt/NF-κB pathway and triggering the apoptosis pathway in vitro. In addition, the in vivo study showed that oroxylin A increased apoptosis of leukemic cells with low systemic toxicity, and the mechanism was the same as in vitro study. In conclusion, all these results showed that oroxylin A improved the sensitivity of K562/ADM cells by increasing apoptosis in leukemic cells and decreasing the expression of CXCR4 and PI3K/Akt/NF-κB pathway, and probably served as a most promising agent for CML treatment.
    Biochemical pharmacology. 05/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In multiple myeloma (MM), the hypoxic environment is an important factor causing tumor angiogenesis which is strongly correlated to disease progression and unfavorable outcome by activating the key transcription factor, hypoxia-inducible factor-1α (HIF-1α). Gambogic acid (GA) is the major active ingredient of gamboge, which has been shown to possess antitumor effect by in vitro and in vivo study. However, the underlying molecular mechanism that whether GA inhibits tumor angiogenesis remains not well understood. In this study, we investigated the effects of GA on expression of HIF-1α, and its downstream target gene vascular endothelial growth factor (VEGF) in human MM U266 cells. We found that hypoxia induced increase in the level of HIF-1α subunit protein and activated the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target protein of rapamycin (mTOR) pathway. Moreover, the treatment with GA markedly decreased HIF-1α and VEGF expression under hypoxic condition. Mechanistic studies exhibited that GA inhibited the production of HIF-1α by reducing phosphorylation of Akt and mTOR in U266 cells. Furthermore, in vivo study revealed that intravenous injection of GA once every other day for two weeks could suppress tumor volumes by antiangiogenesis activity. Taken together, our results identify GA suppress hypoxia-activated pathways that linked to MM progression, at least partly, by the inhibition of PI3K/Akt/mTOR signaling pathway. Therefore, GA may be a new potent therapeutic agent against human MM cells.This article is protected by copyright. All rights reserved.
    Cancer Science 05/2014; · 3.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tumor invasion and migration obstructs the treatment and prognosis of cancer. In this research, we investigated the effect of oroxylin A, a natural compound extracted from Scutellaria radix, the root of Scutellaria baicalensis, on inhibition of the invasion and migration of three different tumor cell lines: MCF-7, DU145, and HepG2. The results suggested that oroxylin A could inhibit hypoxia-induced migration and invasion of the three cell lines mentioned above. To study the detailed mechanisms, studies were carried out on MCF-7 cells and it was found that oroxylin A could regulate the expression of related markers in MCF-7 cells including E-cadherin, N-cadherin, and Vimentin. It was also found that oroxylin A inhibited the hypoxia-induced invasion and migration of MCF-7 cells by suppressing the Notch pathway. Oroxylin A inhibited N1ICD translocating to the nucleus and binding to epithelial-mesenchymal transition-related transcription factor Snail, thus suppressing the invasion and migration of MCF-7 cells. Therefore, oroxylin A is expected to be a promising candidate for antimetastasis treatment through suppression of the hypoxia-induced Notch pathway.
    Anti-cancer drugs 03/2014; · 2.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Gambogic acid (GA), a xanthone derived from the resin of the Garcinia hanburyi, has been demonstrated possessing anti-metastatic activity in vitro and in vivo. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a membrane-anchored glycoprotein negatively regulating matrix metalloproteinases (MMPs), plays an important role in tumor invasion and metastasis. The present study investigates the regulatory effect of GA on RECK expression and the role of RECK in GA-induced anti-invasion in A549 human lung cancer cells. Our results showed that GA dose-dependently inhibited cell invasion and suppressed A549 experimental lung metastasis in vivo, which was attributed to RECK up-regulation at both protein and mRNA levels. With small interference RNA (siRNA) blocking RECK expression, we found inhibition of RECK decreased the GA-induced inhibition of MMP-2/9, which was in consistent with the attenuated anti-invasive effect of GA. Further study indicated that GA effectively suppressed Histone deacetylase (HDAC) 1/specificity protein (Sp) 1 binding and Sp1 phosphorylation associating with Extracellular signal-regulated kinases (ERK) signaling blocking, leading to RECK up-regulation. Taken together, these data demonstrate that RECK contributes to GA's anti-invasive activity and provide new evidence for GA being served as a therapeutic candidate for cancer metastasis. © 2014 Wiley Periodicals, Inc.
    Molecular Carcinogenesis 02/2014; · 4.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Baicalein (5,6,7-trihydroxy-2-phenyl-4H-chromen-4-one), a major flavonoid extracted from the root of Scutellaria baicalensis Georgi (Chinese name: Huangqin), showed potent anti-proliferative activity against a broad panel of human cancer cell lines both in vitro and in vivo. A novel series of baicalein derivatives were synthesized by introducing a group to C6-OH and a nitrogen-containing hydrophilic heterocyclic ring to C7-OH via a length of 3 or 4-carbon chain in this study. The in vitro antiproliferative activities of the 30 derivatives against HepG2, A549, BCG-823 cancer cell lines were evaluated. Among them, 10 compounds exhibit more potent cytotoxicity than baicalein against the three cancer cell lines. The most potent compound 9b possesses highest anti-proliferative potency against HepG2, A549, and BCG-823 with an IC50 value of 2.0μM, 0.8μM and 3.2μM, respectively. Preliminary mechanism studies with compound 9b using Annexin V/PI double-staining assay and DAPI staining assay indicated that 9b inhibits tumor cell proliferation potentially through inducing apoptosis.
    Bioorganic & medicinal chemistry letters 01/2014; · 2.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cancer cell invasion, one of the crucial events in local growth and metastatic spread of tumors, possess a broad spectrum of mechanisms, especially altered expression of matrix metalloproteinases. LFG-500 is a novel synthesized flavonoid with strong anti-cancer activity, whose exact molecular mechanism remains incompletely understood. This current study was designed to examine the effects of LFG-500 on tumor metastasis using in vitro and in vivo assays. LFG-500 could inhibit adhesion, migration and invasion of MDA-MB-231 human breast carcinoma cells. Meanwhile, it reduced the activities and expression of MMP-2 and MMP-9 via suppressing the transcriptional activation of NF-κB rather than AP-1 or STAT3. Moreover, LFG-500 repressed TNF-α induced cell invasion through inhibiting NF-κB and subsequent MMP-9 activity. Further elucidation of the mechanism revealed that PI3K/AKT but not MAPK signaling pathway was involved in the inhibitory effect of LFG-500 on NF-κB activation. LFG-500 could also suppress lung metastasis of B16F10 murine melanoma cells in vivo. Taken together, these results demonstrated that LFG-500 could block cancer cell invasion via down-regulation of PI3K/AKT/NF-κB signaling pathway, which provides new evidence for the anti-cancer activity of LFG-500.
    PLoS ONE 01/2014; 9(3):e91332. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the anticancer effect of LW-214, a newly synthesized flavonoid, against MCF-7 human breast cancer cells and the underlying mechanisms were investigated. LW-214 triggered the mitochondrial apoptotic pathway by increasing Bax/Bcl-2 ratio, loss of mitochondrial membrane potential (ΔΨm) and caspase-9 activation, degradation of poly (ADP-ribose) polymerase (PARP), cytochrome c (Cyt c) release and apoptosis-inducing factor (AIF) transposition. Further research revealed that both the reactive oxygen species (ROS) generation and the apoptosis signal regulating kinase 1 (ASK1) activation by LW-214 were induced by down-regulating the thioredoxin-1 (Trx-1) expression. The ROS elevation and ASK1 activation induced a sustained phosphorylation of c-Jun N-terminal kinase (JNK), while SP600125, as known as JNK inhibitor, almost reversed LW-214-induced apoptosis in MCF-7 cells. Overexpression of Trx-1 in MCF-7 cells attenuated LW-214-mediated apoptosis as well as the JNK activation and reversed the expression of mitochondrial apoptosis-related protein. Accordingly, the in vivo study showed that LW-214 exhibited a potential antitumor effect in BALB/c species mice inoculated MCF-7 tumor with low systemic toxicity, and the mechanism was the same as in vitro study. Taken together, these findings indicated that LW-214 may down-regulated Trx-1 function, causing intracellular ROS generation and releasing the ASK1, and lead to JNK activation, which consequently induced the mitochondrial apoptosis in vitro and in vivo.
    Biochemical pharmacology 12/2013; · 4.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wogonin, a flavone from the root of Scutellaria baicalensis Georgi, has shown various biological activities. In our previous study, it was confirmed that wogonin could decrease the expression of hypoxia-inducible factor-1α (HIF-1α) by affecting its stability under hypoxia. However, it is still unknown whether wogonin could influence Wnt/β-catenin pathway under hypoxia. In this study, we found that wogonin disrupted Wnt/β-catenin signaling and reduced the secretion of vascular endothelial growth factor (VEGF, also known as vascular permeability factor, VPF), which increased vascular permeability in certain diseases. It was found that wogonin suppressed HUVECs hyperactivity and actin remodeling induced by hypoxia, inhibited transendothelial cell migration of the human breast carcinoma cell MDA-MB-231 and the extravasated Evans in vivo Miles vascular permeability assay. Wogonin-treated cells showed a decrease in the expression of Wnt protein and its co-receptors, as well as a parallel increase in the expression of Axin and GSK-3β in degradation complex, leading to degradation of β-catenin. In addition, wogonin promoted the binding between Axin and β-catenin, increased ubiquitination of β-catenin and promoted its degradation. Interestingly, wogonin decreased the expression of TCF-1, TCF-3, and LEF-1 and inhibited nuclear accumulation of β-catenin as well as the binding of β-catenin and TCF-1, TCF-3, or LEF-1. All of the above results showed that wogonin could inhibit the expression of VEGF, which is an important factor regulated by β-catenin. Taken together, the results suggested that wogonin was a potent inhibitor of Wnt/β-catenin and influenced vascular permeability, and this might provide new therapeutics in certain diseases. © 2013 Wiley Periodicals, Inc.
    Molecular Carcinogenesis 10/2013; · 4.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nrf2-mediated activation of ARE regulates expression of cytoprotective enzymes against oxidative stress, inflammation and carcinogenesis. We have discovered a novel structure (1) as an ARE inducer via luciferase reporter assay to screen the in-house database of our laboratory. The potency of 1 was evaluated by the expression of NQO-1, HO-1 and nuclear translocation of Nrf2 in HCT116 cells. In vivo potency of 1 was studied using AOM-DSS models, showing that the development of colorectal adenomas was significantly inhibited. Administration with 1 lowered the expression of IL-6, IL-1β and promoted Nrf2 nuclear translocation. These results indicated that 1 is a potent Nrf2/ARE activator, both in vitro and in vivo. 41 derivatives were synthesized for SAR study, and a more potent compound 17 was identified. To our knowledge, this is a potent ARE activator. Besides, its novel structure makes it promising for further optimization.
    Journal of Medicinal Chemistry 09/2013; · 5.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Oroxylin A (OA) is a flavonoid derived from a Chinese herb that has previously been reported to inhibit the proliferation of several cancer cell lines. It is found that OA significantly inhibited the growth of myeloid leukemia cell lines and as xenografts in immunodeficient mice and primary blasts from acute myelogenous leukemia (AML) patients. Furthermore, OA-induced cell cycle arrest and differentiation were observed in OA-treated AML cell lines. OA-induced increase of CD11b/CD14 expression was reversed by GW9662, a specific PPARγ inhibitor, or transient transfection with PPARγ siRNA. Docking study showed OA bound to ligand-binding-domain of PPARγ via forming hydrogen bonds with Arg288 and Leu340 sites. Results of FP-based ligand assay verified PPARγ binding activity of OA, and in OA-treated cells, intranuclear accumulation and increased binding activity of PPARγ to PPRE were detected. We also found GW9662 attenuated OA-induced up-regulation of C/EBPβ, an important regulator of leukemic differentiation, and p21 which is a potent inhibitor of CDKs that can inhibit phosphorylation of Rb by cyclin D1-CDK4 complexes. Moreover, our results showed that OA displayed synergistic effects with ATRA and VD3 in part related to reduction of intranuclear phosphorylated RXRα that has been reported to block nuclear receptor/RXRα heterodimer transcriptional activity. This reduction of phosphorylated RXRα was associated with inhibition of the specific upstream MAP kinase ERK1/2. We suggest that OA may provide a novel complement to AML treatment by its dual effects of augmenting PPARγ activity and sensitizing nuclear receptors to specific ligands. © 2013 Wiley Periodicals, Inc.
    International Journal of Cancer 08/2013; · 6.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Wogonin, a naturally occurring mono-flavonoid, has been reported to have tumor therapeutic potential and good selectivity both in vitro and in vivo. Herein, we investigated the anti-proliferation effects and associated mechanisms of wogonin in human colorectal cancer in vitro. The flow-cytometric analysis showed that wogonin induced a G1 phase cell cycle arrest in HCT116 cells in a concentration- and time-dependent manner. Meanwhile, the cell cycle-related proteins, such as Cyclin A, E, D1, and CDK2, 4 were down-regulated in wogonin-induced G1 cell cycle arrest. Furthermore, we showed that the anti-proliferation and G1 arrest effect of wogonin on HCT116 cells was associated with deregulation of Wnt/β-catenin signaling pathway. Wogonin-treated cells showed decreased intracellular levels of Wnt proteins, and activated degradation complex to phosphorylated and targeted β-catenin for proteasomal degradation. Wogonin inhibited β-catenin-mediated transcription by interfering in the transcriptional activity of TCF/Lef, and repressing the kinase activity of CDK8 which has been considered as an oncogene involving in the development of colorectal cancers. Moreover, CDK8 siRNA-transfected HCT116 cells showed similar results to wogonin treated cells. Thus, our data suggested that wogonin induced anti-proliferation and G1 arrest via Wnt/β-catenin signaling pathway and it can be developed as a therapeutic agent against human colorectal cancer.
    Toxicology 07/2013; · 4.02 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Malignant gliomas are the most common and most aggressive primary brain tumor, and for which differentiation therapy has emerged as a promising candidate strategy. In this study, we used in vitro and in vivo assays to examine the differentiation effects of wogonin, a major active constituent of Scutellaria baicalensis, on glioma C6 and U251 cells. We found that wogonin can suppress cell proliferationin and induce G0/G1 arrest under a concentration-dependent manner. Wogonin also triggered significant reduction in the G1 cell-cycle regulatory proteins cyclin D1, cyclin-dependent kinase 2 and 4 along with overexpression of cell-cycle inhibitory proteins p27. Immunofluorescence and western blot analysis indicated that wogonin increased the expression of lineage-specific differentiation markers glial fibrillary acidic protein (GFAP). In mechanisms, we verified that wogonin significantly diminished the phosphorylated level of protein kinase B (AKT), and maintenance of low β-catenin expression level was dependent on glycogen synthase kinase 3β (GSK3β) activation at Ser9. Blocking GSK3β/β-catenin pathway was required for wogonin-induced proliferation inhibition and terminal differentiation by using canonical activator lithium chloride (LiCl) and inhibitor dickkopf-1 (Dkk1). Moreover, intravenous administration of wogonin delayed the growth of C6 glioma in the intracranial tumor model. These findings provide the evidence and mechanistic support for wogonin-based differentiation therapies for malignant glioblastoma. Furthermore, inhibition of GSK3β/β-catenin pathway may be a key and requisite factor in glioma differentiation.
    Toxicology Letters 07/2013; · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Natural flavonoids from plants have been demonstrated to possess promising chemopreventive activities against various diseases. 7-{4-[Bis-(2-hydroxy-ethyl)-amino]-butoxy}-5-hydroxy-8-methoxy-2-phenyl-chromen-4-one (V8), a newly synthesized derivative of wogonin may have antioxidant, antiviral, anti-inflammatory and anti-tumor potentials as wogonin. Based on the recent findings of V8, the anti-tumor activities and fundamental mechanisms by which V8 inhibits growth of hepatocellular carcinoma were further investigated in this study. After the treatment of V8, a significant inhibition of HepG2 cell proliferation was observed in a dose-dependent manner with the IC50 value of 23 μM using MTT assay. The exposure to V8 also resulted in apoptosis induction and an accumulation of ROS and Ca(2+). Meanwhile, a release of cytochrome c (Cyt-c), activation of BH-3 only proteins and Bax, decrease in mitochondrial membrane potential ΔΨ, as well as a suppression of Bcl-2, pro-caspase9 and pro-caspase3 expression were shown. Moreover, knocking down CHOP partly decreased the effect of V8-mediated apoptosis and activation of GRP78, p-PERK, p-eIF2α, ATF4 and CHOP modulated ER stress triggered by V8. In vivo, V8 inhibited the transplanted mice H22 liver carcinomas in a dose-dependent manner. Compared with wogonin, V8 exhibited stronger anti-proliferative effects both in vitro and in vivo. The underlying mechanism of activating PERK-eIF2α-ATF4 pathway by which V8 induces apoptosis was verified once again in vivo. The apoptosis induction via the mitochondrial pathway by modulating the ROS-mediated ER signaling pathway might serve to provide support for further studies of V8 as a possible anticancer drug in the clinical treatment of cancer.
    Archives of Toxicology 07/2013; · 5.22 Impact Factor

Publication Stats

665 Citations
323.23 Total Impact Points

Institutions

  • 2007–2013
    • China Pharmaceutical University
      • • Jiangsu Key Laboratory of Carcinogenesis and Intervention
      • • School of Life Science and Technology
      • • Department of Physiology
      Nan-ching-hsü, Jiangxi Sheng, China