lignans and Glioblastoma

Glioblastoma (GBM) is the most common malignant tumor of the adult central nervous system. Aberrant regulation of cell death is an important feature of GBM, and investigating the regulatory mechanisms of cell death in GBM may provide insights into development of new therapeutic strategies. We demonstrated that myrislignan has ferroptosis-promoting activity. Myrislignan is a lignan isolated from

Topics: Animals; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Ferroptosis; Glioblastoma; Humans; I-kappa B Proteins; Lignans; Mice; NF-kappa B

Forkhead Box M1 (FOXM1) is known to regulate cell proliferation, apoptosis and tumorigenesis. The lignan, (-)-(2R,3R)-1,4-O-diferuloylsecoisolariciresinol (DFS), from Alnus japonica has shown anti-cancer effects against colon cancer cells by suppressing FOXM1. The present study hypothesized that DFS can have anti-cancer effects against glioblastoma (GBM) tumorspheres (TSs). Immunoprecipitation and luciferase reporter assays were performed to evaluate the ability of DFS to suppress nuclear translocation of β-catenin through β-catenin/FOXM1 binding. DFS-pretreated GBM TSs were evaluated to assess the ability of DFS to inhibit GBM TSs and their transcriptional profiles. The in vivo efficacy was examined in orthotopic xenograft models of GBM. Expression of FOXM1 was higher in GBM than in normal tissues. DFS-induced FOXM1 protein degradation blocked β-catenin translocation into the nucleus and consequently suppressed downstream target genes of FOXM1 pathways. DFS inhibited cell viability and ATP levels, while increasing apoptosis, and it reduced tumorsphere formation and the invasiveness of GBM TSs. And DFS reduced the activities of transcription factors related to tumorigenesis, stemness, and invasiveness. DFS significantly inhibited tumor growth and prolonged the survival rate of mice in orthotopic xenograft models of GBM. It suggests that DFS inhibits the proliferation of GBM TSs by suppressing FOXM1. DFS may be a potential therapeutic agent to treat GBM.

Topics: Alnus; Animals; beta Catenin; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Forkhead Box Protein M1; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Lignans; Mice

Glioblastoma (GBM) responses to bevacizumab are invariably transient with acquired resistance. We profiled paired patient specimens and bevacizumab-resistant xenograft models pre- and post-resistance toward the primary goal of identifying regulators whose targeting could prolong the therapeutic window, and the secondary goal of identifying biomarkers of therapeutic window closure. Bevacizumab-resistant patient specimens and xenografts exhibited decreased vessel density and increased hypoxia versus pre-resistance, suggesting that resistance occurs despite effective therapeutic devascularization. Microarray analysis revealed upregulated mesenchymal genes in resistant tumors correlating with bevacizumab treatment duration and causing three changes enabling resistant tumor growth in hypoxia. First, perivascular invasiveness along remaining blood vessels, which co-opts vessels in a VEGF-independent and neoangiogenesis-independent manner, was upregulated in novel biomimetic 3D bioengineered platforms modeling the bevacizumab-resistant microenvironment. Second, tumor-initiating stem cells housed in the perivascular niche close to remaining blood vessels were enriched. Third, metabolic reprogramming assessed through real-time bioenergetic measurement and metabolomics upregulated glycolysis and suppressed oxidative phosphorylation. Single-cell sequencing of bevacizumab-resistant patient GBMs confirmed upregulated mesenchymal genes, particularly glycoprotein YKL-40 and transcription factor ZEB1, in later clones, implicating these changes as treatment-induced. Serum YKL-40 was elevated in bevacizumab-resistant versus bevacizumab-naïve patients. CRISPR and pharmacologic targeting of ZEB1 with honokiol reversed the mesenchymal gene expression and associated stem cell, invasion, and metabolic changes defining resistance. Honokiol caused greater cell death in bevacizumab-resistant than bevacizumab-responsive tumor cells, with surviving cells losing mesenchymal morphology. Employing YKL-40 as a resistance biomarker and ZEB1 as a target to prevent resistance could fulfill the promise of antiangiogenic therapy. SIGNIFICANCE: Bevacizumab resistance in GBM is associated with mesenchymal/glycolytic shifts involving YKL-40 and ZEB1. Targeting ZEB1 reduces bevacizumab-resistant GBM phenotypes. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/7/1498/F1.large.jpg.

Topics: Adult; Aged; Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Biphenyl Compounds; Brain; Brain Neoplasms; Cell Hypoxia; Cell Line, Tumor; Chitinase-3-Like Protein 1; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Female; Gene Expression Regulation, Neoplastic; Glioblastoma; Human Umbilical Vein Endothelial Cells; Humans; Lignans; Male; Middle Aged; Neoplasm Invasiveness; Neoplastic Stem Cells; Neovascularization, Pathologic; Tumor Microenvironment; Up-Regulation; Xenograft Model Antitumor Assays; Young Adult; Zinc Finger E-box-Binding Homeobox 1

Temozolomide (TMZ)-induced chemoresistance to human glioblastomas is a critical challenge now. Our previous studies showed that honokiol, a major bioactive constituent of

Topics: Apoptosis; Biphenyl Compounds; Caspase 9; Cell Line, Tumor; Drug Resistance, Neoplasm; Enzyme Activation; Glioblastoma; Humans; Lignans; Mitochondria; Neoplasm Proteins; Temozolomide

Arctigenin (ARG) is a natural lignan compound extracted from Arctium lappa and has displayed anticancer function and therapeutic effect in a variety of cancers. Arctigenin is mainly from Arctium lappa extract. It has been shown to induce autophagy in various cancers. However, as for whether arctigenin induces autophagy in gliomas or not, the specific mechanism is still worth exploring.. Using CCK8, the monoclonal experiment was made to detect the proliferation ability. The scratch experiment and the transwell experiment were applied to the migration and invasion ability. PI/RNase and FITC-conjugated anti-annexin V were used to detect the cell cycle and apoptosis. Western blotting was used to determine the specified protein level, and constructed LC3B-GFP plasmid was used for analysis of autophagy.. Our research showed that ARG inhibited the growth and proliferation and invasion and migration of glioma cells in a dose-dependent manner (U87MG and T98G) and arrested the cell cycle and induced apoptosis. Interestingly, ARG induced autophagy in a dose-dependent manner. We applied Western blotting to measure the increase in the key autophagy protein LC3B, as well as some other autophagy-related proteins (increase in Beclin-1 and decrease in P62). In order to further explore the mechanism that ARG passed initiating autophagy to inhibit cell growth, we further found by Western blotting that AKT and mTOR phosphorylation proteins (P-AKT, P-mTOR) were reduced after ARG treatment, and we used AKT agonists to rescue, and the phosphorylated proteins of AKT and mTOR increased, and we found that the autophagy-related proteins were also reversed. And interestingly, the protein of apoptosis was also reversed along with autophagy.. We thought ARG inhibited the proliferation of glioma cells by inducing autophagy and apoptosis through the AKT/mTOR pathway.

Topics: Apoptosis; Autophagy; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Furans; Glioblastoma; Glioma; Humans; Lignans; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases

Plant-derived lignans have numerous biological effects including anti-tumor and anti-inflammatory activities. Screening of purified constituents of Rubia philippinensis from human glioblastoma cells resistant to TNF-related apoptosis-inducing ligand (TRAIL) has suggested that the lignan pinoresinol was a highly active TRAIL sensitizer. Here we show that treatment with nontoxic doses of pinoresinol in combination with TRAIL induced rapid apoptosis and caspase activation in many types of glioblastoma cells, but not in normal astrocytes. Analyses of apoptotic signaling events revealed that pinoresinol enhanced the formation of TRAIL-mediated death-inducing signaling complex (DISC) and complete processing of procaspase-8 within the DISC in glioblastoma cells, in which caspase-8 was inactivated. Mechanistically, pinoresinol downregulated the expression of cellular FLICE-inhibitory protein (cFLIP

Topics: Apoptosis; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Cell Line, Tumor; Cell Membrane; Furans; Glioblastoma; Humans; Lignans; NF-kappa B; Receptors, TNF-Related Apoptosis-Inducing Ligand; Rubia; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand

H2-P, a derivative of honokiol, was first synthesized in our laboratory. Compared with honokiol, H2-P has even high anti-tumor activity. In the present study, we evaluated the ability of H2-P to inhibit the survival rate in four gliomas cell lines. The result showed that H2-P could significantly inhibit proliferation of gliomas cells in a dose-dependent manner (IC50

Topics: Angiogenesis Inhibitors; Animals; Biphenyl Compounds; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Chickens; Chorioallantoic Membrane; Female; Glioblastoma; Humans; Lignans; Mice; Proto-Oncogene Proteins c-myc; Rats; Signal Transduction; Xenograft Model Antitumor Assays

Glioblastoma multiforme (GBM), a prevalent brain cancer with high mortality, is resistant to the conventional single-agent chemotherapy. In this study, we employed a combination chemotherapy strategy to inhibit GBM growth and addressed its possible beneficial effects. The synergistic effect of lauroyl-gemcitabine (Gem-C

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Biphenyl Compounds; Brain Neoplasms; Cell Line, Tumor; Deoxycytidine; Drug Carriers; Drug Compounding; Gemcitabine; Glioblastoma; Humans; Hyaluronan Receptors; Hyaluronic Acid; Lignans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Micelles; Nanoparticles; Rats; Rats, Sprague-Dawley; Spheroids, Cellular; Survival Rate; Treatment Outcome; Xenograft Model Antitumor Assays

Glioblastoma is a primary malignant brain tumor with a poor prognosis. An effective treatment for glioblastoma is needed. Magnolol is a natural compound from Magnolia officinalis suggested to have antiproliferative activity. The aim of this research was to investigate the anticancer effects of magnolol in glioma, with an emphasis on migration and the underlying mechanism. Magnolol decreased the expression of focal adhesion-related proteins and inhibited LN229 and U87MG glioma cell migration. The levels of phosphorylated myosin light chain (p-MLC), phosphorylated myosin light chain kinase and myosin phosphatase target subunit 1 were reduced in response to magnolol treatment. In addition, immunostaining and membrane fractionation showed that the distribution of N-cadherin at the glioma cell membrane was decreased by magnolol. In an orthotropic xenograft animal model, magnolol treatment not only inhibited tumor progression but also reduced p-MLC and N-cadherin protein expression. In conclusion, magnolol reduces cell migration, potentially through regulating focal adhesions and N-cadherin in glioma cells. Magnolol is a potential candidate for glioma treatment.

Topics: Animals; Antineoplastic Agents, Phytogenic; Biphenyl Compounds; Brain Neoplasms; Cadherins; Cell Line, Tumor; Cell Movement; Cell Survival; Glioblastoma; Humans; Lignans; Mice; Mice, Inbred BALB C; Myosin-Light-Chain Kinase; Neoplasm Transplantation; Phosphorylation; Wound Healing

Many types of cancer express high levels of heat shock proteins (HSPs) that are molecular chaperones regulating protein folding and stability ensuring protection of cells from potentially lethal stress. HSPs in cancer cells promote survival, growth and spreading even in situations of growth factors deprivation by associating with oncogenic proteins responsible for cell transformation. Hence, it is not surprising that the identification of potent inhibitors of HSPs, notably HSP90, has been the primary research focus, in recent years. Exposure of cancer cells to HSP90 inhibitors, including 17-AAG, has been shown to cause resistance to chemotherapeutic treatment mostly attributable to induction of the heat shock response and increased cellular levels of pro-survival chaperones. In this study, we show that treatment of glioblastoma cells with 17-AAG leads to HSP90 inhibition indicated by loss of stability of the EGFR client protein, and significant increase in HSP70 expression. Conversely, co-treatment with the small-molecule kinase inhibitor D11 leads to suppression of the heat shock response and inhibition of HSF1 transcriptional activity. Beside HSP70, Western blot and differential mRNA expression analysis reveal that combination treatment causes strong down-regulation of the small chaperone protein HSP27. Finally, we demonstrate that incubation of cells with both agents leads to enhanced cytotoxicity and significantly high levels of LC3-II suggesting autophagy induction. Taken together, results reported here support the notion that including D11 in future treatment regimens based on HSP90 inhibition can potentially overcome acquired resistance induced by the heat shock response in brain cancer cells.

Topics: Benzoquinones; Brain Neoplasms; Casein Kinase II; Cell Line, Tumor; DNA-Binding Proteins; Down-Regulation; Drug Interactions; Drug Resistance, Neoplasm; Glioblastoma; Glucosides; Heat Shock Transcription Factors; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Lignans; Protein Kinase Inhibitors; Transcription Factors; Transcription, Genetic; Transcriptome; Up-Regulation

Our previous study showed that honokiol, a bioactive polyphenol, can traverse the blood-brain barrier and kills neuroblastoma cells.. In this study, we further evaluated the preclinical effects of honokiol on development of malignant glioma and the possible mechanisms.. Effects of honokiol on viability, caspase activities, apoptosis, and cell cycle arrest in human glioma U87 MG or U373MG cells were assayed. As to the mechanisms, levels of inactive or phosphorylated (p) p53, p21, CDK6, CDK4, cyclin D1, and E2F1 were immunodetected. Pifithrin-α (PFN-α), a p53 inhibitor, was pretreated into the cells. Finally, our in vitro findings were confirmed using intracranial nude mice implanted with U87 MG cells.. Exposure of human U87 MG glioma cells to honokiol decreased the cell viability. In parallel, honokiol induced activations of caspase-8, -9, and -3, apoptosis, and G1 cell cycle arrest. Treatment of U87 MG cells with honokiol increased p53 phosphorylation and p21 levels. Honokiol provoked signal-transducing downregulation of CDK6, CDK4, cyclin D1, phosphorylated (p)RB, and E2F1. Pretreatment of U87 MG cells with PFN-α significantly reversed honokiol-induced p53 phosphorylation and p21 augmentation. Honokiol-induced alterations in levels of CDK6, CDK4, cyclin D1, p-RB, and E2F1 were attenuated by PFN-α. Furthermore, honokiol could induce apoptotic insults to human U373MG glioma cells. In our in vivo model, administration of honokiol prolonged the survival rate of nude mice implanted with U87 MG cells and induced caspase-3 activation and chronological changes in p53, p21, CDK6, CDK4, cyclin D1, p-RB, and E2F1.. Honokiol can repress human glioma growth by inducing apoptosis and cell cycle arrest in tumor cells though activating a p53/cyclin D1/CDK6/CDK4/E2F1-dependent pathway. Our results suggest the potential of honokiol in therapies for human malignant gliomas.

Topics: Animals; Apoptosis; Benzothiazoles; Biphenyl Compounds; Caspases; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Line, Tumor; Down-Regulation; Drug Evaluation, Preclinical; Female; G1 Phase; Glioblastoma; Humans; Lignans; Mice; Mice, Inbred BALB C; Mice, Nude; Toluene; Tumor Suppressor Protein p53

Glioblastoma (GBM) is a malignant brain tumor associated with a high mortality rate. The aim of this study is to investigate the synergistic effects of honokiol (Hono) and magnolol (Mag), extracted from Magnolia officinalis, on cytotoxicity and inhibition of human GBM tumor progression in cellular and animal models. In comparison with Hono or Mag alone, co-treatment with Hono and Mag (Hono-Mag) decreased cyclin A, D1 and cyclin-dependent kinase 2, 4, 6 significantly, leading to cell cycle arrest in U87MG and LN229 human glioma cells. In addition, phosphorylated phosphoinositide 3-kinase (p-PI3K), p-Akt, and Ki67 were decreased after Hono-Mag treatment, showing proliferation inhibition. Hono-Mag treatment also reduced p-p38 and p-JNK but elevated p-ERK expression. Besides, Hono-Mag treatment induced autophagy and intrinsic and extrinsic apoptosis. Both ERK and autophagy inhibitors enhanced Hono-Mag-induced apoptosis in LN229 cells, indicating a rescuer role of ERK. In human GBM orthotopic xenograft model, the Hono-Mag treatment inhibited the tumor progression and induced apoptosis more efficiently than Temozolomide, Hono, or Mag group. In conclusion, the Hono-Mag exerts a synergistic anti-tumor effect by inhibiting cell proliferation and inducing autophagy and apoptosis in human GBM cells. The Hono-Mag may be applied as an adjuvant therapy to improve the therapeutic efficacy of GBM treatment.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Biphenyl Compounds; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Synergism; Glioblastoma; Humans; Lignans; Mice; Mice, Nude; Xenograft Model Antitumor Assays

Glioblastoma multiforme (GBM) is the most common adult malignant glioma with poor prognosis due to the resistance to radiotherapy and chemotherapy, which might be critically involved in the repopulation of cancer stem cells (CSCs) after treatment. We had investigated the characteristics of cancer stem-like side population (SP) cells sorted from GBM cells, and studied the effect of Honokiol targeting on CSCs. GBM8401 SP cells possessed the stem cell markers, such as nestin, CD133 and Oct4, and the expressions of self-renewal related stemness genes, such as SMO, Notch3 and IHH (Indian Hedgehog). Honokiol inhibited the proliferation of both GBM8401 parental cells and SP cells in a dose-dependent manner, the IC50 were 5.3±0.72 and 11±1.1 μM, respectively. The proportions of SP in GBM8401 cells were diminished by Honokiol from 1.5±0.22% down to 0.3±0.02% and 0.2±0.01% at doses of 2.5 μM and 5 μM, respectively. The SP cells appeared to have higher expression of O6-methylguanine-DNA methyltransferase (MGMT) and be more resistant to Temozolomide (TMZ). The resistance to TMZ could be only slightly reversed by MGMT inhibitor O6-benzylguanine (O6-BG), but markedly further enhanced by Honokiol addition. Such significant enhancement was accompanied with the higher induction of apoptosis, greater down-regulation of Notch3 as well as its downstream Hes1 expressions in SP cells. Our data indicate that Honokiol might have clinical benefits for the GBM patients who are refractory to TMZ treatment.

Topics: Antineoplastic Agents; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Biphenyl Compounds; Brain Neoplasms; Cell Proliferation; Dacarbazine; Dose-Response Relationship, Drug; Down-Regulation; Drug Synergism; Drug Therapy, Combination; Glioblastoma; Homeodomain Proteins; Humans; Lignans; Neoplastic Stem Cells; Receptor, Notch3; Receptors, Notch; Temozolomide; Transcription Factor HES-1; Tumor Cells, Cultured

Glioblastoma is one of the most lethal and prevalent malignant human brain tumors, with aggressive proliferation and highly invasive properties. There is still no effective cure for patients with glioblastoma. Honokiol, derived from Magnolia officinalis, can cross the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB), making it a strong candidate for an effective drug for the treatment of brain tumors, including glioblastoma. In our previous study, we demonstrated that honokiol effectively induced apoptotic cell death in glioblastoma. Metastasis poses the largest problem to cancer treatment and is the primary cause of death in cancer patients. Thus, in this study, we investigated the effect of honokiol on the cell invasion process of U87MG human glioblastoma cells through brain microvascular endothelial cells (BMECs) and its possible mechanisms. Honokiol dose-dependently inhibited TNF-α-induced VCAM-1 expression in BMECs and adhesion of U87MG to BMECs. Moreover, honokiol effectively blocked U87MG invasion through BMEC-Matrigel-coated transwell membranes. Increased phosphorylation of VE-cadherin and membrane permeability by TNF-α were suppressed by honokiol in BMECs. Furthermore, we investigated the effect of honokiol on the epithelial-mesenchymal transition (EMT) in U87MG cells. Honokiol reduced the expression levels of Snail, N-cadherin and β-catenin, which are mesenchymal markers, but increased E-cadherin, an epithelial marker. In conclusion, these results suggest that honokiol inhibits metastasis by targeting the interaction between U87MG and BMECs, regulating the adhesion of U87MG to BMECs by inhibiting VCAM-1, and regulating the invasion of U87MG through BMECs by reducing membrane permeability and EMT processes of U87MG cells.

Topics: Apoptosis; Biphenyl Compounds; Brain Neoplasms; Cell Line, Tumor; Cell Membrane Permeability; Endothelial Cells; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Lignans; Neoplasm Invasiveness; Vascular Cell Adhesion Molecule-1

Biphenyl neolignans such as honokiol and magnolol, which are the major active constituents of the Asian medicinal plant Magnolia officinalis, are known to exert a multitude of pharmacological and biological activities. Among these, cytotoxic and tumor growth inhibitory activity against various tumour cell lines are well-documented. To further elucidate the cytotoxic effects of honokiol derivatives, derivatizations were performed using tetrahydrohonokiol as a scaffold. The derivatizations comprised the introduction of functional groups, e.g., nitro and amino groups, as well as alkylation. This way, 18 derivatives, of which 13 were previously undescribed compounds, were evaluated against CCRF-CEM leukemia cells, U251 glioblastoma and HCT-116 colon cancer cells. The results revealed no significant cytotoxic effects in any of the three tested cell lines at a test concentration of 10 µM.

Topics: Antineoplastic Agents, Phytogenic; Biphenyl Compounds; Cell Survival; Colonic Neoplasms; Drug Screening Assays, Antitumor; Glioblastoma; HCT116 Cells; Humans; Inhibitory Concentration 50; Leukemia; Lignans; Methylation; Microwaves

Honokiol, an active constituent of oriental medicinal herb Magnolia officinalis, caused Ca(2+) mobilization and apoptosis in different cancer cells. In vivo, honokiol crossed the blood-brain or -cerebrospinal fluid barrier, suggesting that it may be an effective drug for the treatment of brain tumors, including glioblastoma. This study examined the effect of honokiol on intracellular Ca(2+) concentration ([Ca(2+)]i) and apoptosis in DBTRG-05MG human glioblastoma cells. Honokiol concentration-dependently induced a [Ca(2+)]i rise. The signal was decreased partially by removal of extracellular Ca(2+). Honokiol-triggered [Ca(2+)]i rise was not suppressed by store-operated Ca(2+) channel blockers (nifedipine, econazole, SK&F96365) and the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate (PMA), but was inhibited by the PKC inhibitor GF109203X. GF109203X-induced inhibition was not altered by removal of extracellular Ca(2+). In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (TG) or 2,5-di-tert-butylhydroquinone (BHQ) abolished honokiol-induced [Ca(2+)]i rise. Conversely, incubation with honokiol abolished TG or BHQ-induced [Ca(2+)]i rise. Inhibition of phospholipase C (PLC) with U73122 abolished honokiol-induced [Ca(2+)]i rise. Honokiol (20-80μM) reduced the cell viability, which was not reversed by prechelating cytosolic Ca(2+) with BAPTA-AM (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester). Honokiol (20-60μM) enhanced reactive oxygen species (ROS) production, decreased mitochondrial membrane potential, released cytochrome c, and activated caspase-9/caspase-3. Together, honokiol induced a [Ca(2+)]i rise by inducing PLC-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via PKC-dependent, non store-operated Ca(2+) channels. Moreover, honokiol activated the mitochondrial pathway of apoptosis in DBTRG-05MG human glioblastoma cells.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Biphenyl Compounds; Calcium; Calcium Signaling; Cell Line, Tumor; Cell Survival; Estrenes; Glioblastoma; Homeostasis; Humans; Lignans; Phosphodiesterase Inhibitors; Pyrrolidinones; Up-Regulation

Honokiol [3,5-di-(2-propenyl)-1,1-biphenyl-2,2-diol; HNK], a natural bioactive molecular compound isolated from the Magnolia officinalis, exhibits potent antitumor activity against a variety of human cancer cell lines. However, few studies have reported the antineoplastic effects of HNK on glioblastoma cells. It remains unknown how apoptosis is induced by HNK in glioblastoma cells and through which associated pathway this compound acts. The present study confirmed that HNK inhibited proliferation of glioblastoma cells by inducing a slight G0/G1 phase cell cycle arrest and apoptosis. We demonstrated for the first time that HNK triggered apoptosis of glioblastoma cells through both caspase-independent and caspase-dependent pathways, the latter including the extrinsic pathway and intrinsic pathway. Moreover, the inhibition of STAT3 signaling, ERK1/2 as well as activation of the p38 MAPK signaling pathway may be involved in apoptosis induced by HNK in U87 cells. Our findings suggest that HNK treatment could be a promising therapeutic strategy in human glioblastoma.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Lignans; MAP Kinase Signaling System; STAT3 Transcription Factor

Previously, we demonstrated that magnolol, a hydroxylated biphenyl compound isolated from the bark of Magnolia officinalis, at low concentrations (3-10 μM) exerted an antiproliferation effect in colon cancer, hepatoma, and glioblastoma (U373) cell lines through upregulation of the p21/Cip1 protein. Magnolol at a higher concentration of 100 μM, however, induced apoptosis and upregulated p27/Kip1 expression in U373. In the present study, we further studied whether the increased p27/Kip1 expression contributes to the magnolol-induced apoptosis in U373. Our data show that knock-down of p27/Kip1 expression significantly suppressed the magnolol-induced apoptosis, suggesting that p27/Kip1 might play an important role in the regulation of magnolol-induced apoptosis. This notion was further supported by demonstrating that magnolol induced an increase of the caspase activity in U373 in vitro and in vivo, and these effects were abolished by pretransfection of the cell with p27/Kip1 siRNA. To delineate the possible signaling pathways involved in the magnolol-induced increases of p27/Kip1 expression and apoptosis, we found that magnolol (100 μM) increased the levels of phosphorylated cSrc (p-cSrc), p-ERK, p-p38 MAP kinase (p-p38 MAPK), and p-AKT but not p-JNK in U373. Moreover, pretreatment of U373 with a cSrc inhibitor (PP2), a PI3K inhibitor (LY294002), an ERK inhibitor (PD98059), or a p38 MAPK inhibitor (SB203580) but not a JNK inhibitor (SP600125) significantly reduced the magnolol-induced increases of p27/Kip1 protein levels and apoptosis. Taken together, our data suggest that magnolol at a higher concentration of 100 μM induced apopotosis in U373 cells through cSrc-mediated upregulation of p27/Kip1.

Topics: Animals; Apoptosis; Biphenyl Compounds; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p27; Female; Glioblastoma; Humans; Lignans; Magnolia; Male; Mice; Mice, Nude; Plant Extracts; Signal Transduction; Up-Regulation

Glioblastoma is one of the most lethal and common malignant human brain tumors, with aggressive proliferation and highly invasive properties. Honokiol derived from Magnolia officinalis is able to cross the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB), suggesting a strong possibility that it could be an effective drug for the treatment of brain tumors, including glioblastoma. Thus, we investigated the effects of honokiol on the expression of adhesion molecules in TNF-α-stimulated endothelial cells, and cancer growth and invasion were determined in T98G human glioblastoma cells. Honokiol dose-dependently inhibited the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) stimulated with TNF-α for 6 h. Pretreatment with honokiol significantly reduced the adhesion of T98G cells to HUVECs. Moreover, honokiol inhibited the invasion of T98G cells, suggesting that honokiol has an anti-metastatic effect. In addition, honokiol increased the cytotoxicity of T98G cells in a dose- and time-dependent manner as assayed by MTT. TUNEL assay showed that honokiol significantly induced apoptosis in T98G cells at doses of 10 µM or more. The induction of apoptotic cell death was mediated by the downregulation of the anti-apoptotic protein Bcl-2 and the upregulation of the pro-apoptotic protein Bax. Taken together, the results of this study suggest that honokiol exerts an anticancer effect by preventing metastasis and inducing apoptotic cell death of brain tumor cells.

Topics: Apoptosis; Biphenyl Compounds; Blood-Brain Barrier; Brain Neoplasms; Cell Adhesion; Cell Adhesion Molecules; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Glioblastoma; Human Umbilical Vein Endothelial Cells; Humans; Intercellular Adhesion Molecule-1; Lignans; Magnolia; Plant Extracts; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1

Previously, we demonstrated that magnolol isolated from the bark of Magnolia officinalis has anticancer activity in colon, hepatoma, and leukemia cell lines. In this study, we show that magnolol concentration dependently (0-40 microM) decreased the cell number in a cultured human glioblastoma cancer cell line (U373) and arrested the cells at the G0/G1 phase of the cell cycle. Magnolol treatment decreased the protein levels of cyclins A and D1 and increased p21/Cip1, but not cyclins B and D3, cyclin-dependent kinase (CDK)2, CDK4, CDC25C, Weel, p27/Kip1, and p53. The CDK2-p21/Cip1 complex was increased, and the CDK2 kinase activity was decreased in the magnolol-treated U373. Pretreatment of U373 with p21/Cip1 specific antisense oligodeoxynucleotide prevented the magnolol-induced increase of p21/Cip1 protein levels and the decrease of DNA synthesis. Magnolol at a concentration of 100 microM induced DNA fragmentation in U373. Our findings suggest the potential applications of magnolol in the treatment of human brain cancers.

Topics: Biphenyl Compounds; Cell Cycle; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Down-Regulation; Glioblastoma; Humans; Lignans; Magnolia; Plant Extracts

Vascular endothelial cells (ECs) that initiate tumor angiogenesis may acquire distinct properties after conditioning in tumor microenvironment as compared to ECs in non-malignant tissues. Thus far, most in vitro studies of angiogenesis used ECs isolated from normal tissues, which may not fully represent the nature of ECs in tumor vasculature. In this study, glioma-derived microvascular ECs (GDMEC) were purified from human glioma tissues by incubating with magnetic beads coated with anti-CD105 antibody and highly pure (98%) preparations of GDMEC were obtained. These cells exhibited typical EC phenotype, and proliferated rapidly in culture. Interestingly, GDMEC expressed higher levels of VEGF receptors, flt-1 and flk-1, as compared to an established human EC cell line ECV304 and primary human umbilical vascular EC (HUVEC). Functionally, GDMEC were capable of forming intercellular junctions and tubule-like structures (TLS) of various sizes. Stimulation by VEGF further promoted TLS formation with diverse tubular walls by GDMEC. In contrast, TLS formed by ECV304 and HUVEC showed significantly different features. We further observed that Nordy, a synthetic lipoxygenase inhibitor, potently inhibited TLS formation by GDMEC. The results suggest that isolation of highly pure ECs derived from tumor tissues is more appropriate for studies of tumor angiogenesis and for test of potential anti-cancer therapeutic targets.

Topics: Astrocytoma; Brain Neoplasms; Cell Line; Cells, Cultured; Endothelium, Vascular; Glioblastoma; Glioma; Humans; Immunomagnetic Separation; In Vitro Techniques; Lignans; Masoprocol; Microcirculation; Models, Biological; Neovascularization, Pathologic; Spheroids, Cellular; Vascular Endothelial Growth Factor A