Moscatilin Inhibits Metastatic Behavior of Human Hepatocellular Carcinoma Cells: A Crucial Role of uPA Suppression via Akt/NF-κB-Dependent Pathway.

Hepatocellular carcinoma (HCC) frequently shows early invasion into blood vessels as well as intrahepatic metastasis. Innovations of novel small-molecule agents to block HCC invasion and subsequent metastasis are urgently needed. Moscatilin is a bibenzyl derivative extracted from the stems of a traditional Chinese medicine, orchid Dendrobium loddigesii. Although moscatilin has been reported to suppress tumor angiogenesis and growth, the anti-metastatic property of moscatilin has not been elucidated. The present results revealed that moscatilin inhibited metastatic behavior of HCC cells without cytotoxic fashion in highly invasive human HCC cell lines. Furthermore, moscatilin significantly suppressed the activity of urokinase plasminogen activator (uPA), but not matrix metalloproteinase (MMP)-2 and MMP-9. Interestingly, moscatilin-suppressed uPA activity was through down-regulation the protein level of uPA, and did not impair the uPA receptor and uPA inhibitory molecule (PAI-1) expressions. Meanwhile, the mRNA expression of uPA was inhibited via moscatilin in a concentration-dependent manner. In addition, the expression of phosphorylated Akt, rather than ERK1/2, was inhibited by moscatilin treatment. The expression of phosphor-IκBα, and -p65, as well as κB-luciferase activity were also repressed after moscatilin treatment. Transfection of constitutively active Akt (Myr-Akt) obviously restored the moscatilin-inhibited the activation of NF-κB and uPA, and cancer invasion in HCC cells. Taken together, these results suggest that moscatilin impedes HCC invasion and uPA expression through the Akt/NF-κB signaling pathway. Moscatilin might serve as a potential anti-metastatic agent against the disease progression of human HCC.

Activated PAR-2 regulates pancreatic cancer progression through ILK/HIF-α-induced TGF-α expression and MEK/VEGF-A-mediated angiogenesis.

Tissue factor initiates the process of thrombosis and activates cell signaling through protease-activated receptor-2 (PAR-2). The aim of this study was to investigate the pathological role of PAR-2 signaling in pancreatic cancer. We first demonstrated that activated PAR-2 up-regulated the protein expression of both hypoxia-inducible factor-1α (HIF-1α) and HIF-2α, resulting in enhanced transcription of transforming growth factor-α (TGF-α). Down-regulation of HIFs-α by siRNA or YC-1, an HIF inhibitor, resulted in depleted levels of TGF-α protein. Furthermore, PAR-2, through integrin-linked kinase (ILK) signaling, including the p-AKT, promoted HIF protein expression. Diminishing ILK by siRNA decreased the levels of PAR-2-induced p-AKT, HIFs-α, and TGF-α; our results suggest that ILK is involved in the PAR-2-mediated TGF-α via an HIF-α-dependent pathway. Furthermore, the culture medium from PAR-2-treated pancreatic cancer cells enhanced human umbilical vein endothelial cell proliferation and tube formation, which was blocked by the MEK inhibitor, PD98059. We also found that activated PAR-2 enhanced tumor angiogenesis through the release of vascular endothelial growth factor-A (VEGF-A) from cancer cells, independent of the ILK/HIFs-α pathways. Consistent with microarray analysis, activated PAR-2 induced TGF-A and VEGF-A gene expression. In conclusion, the activation of PAR-2 signaling induced human pancreatic cancer progression through the induction of TGF-α expression by ILK/HIFs-α, as well as through MEK/VEGF-A-mediated angiogenesis, and it plays a role in the interaction between cancer progression and cancer-related thrombosis.

CHM-1, a new vascular targeting agent, induces apoptosis of human umbilical vein endothelial cells via p53-mediated death receptor 5 up-regulation.

CHM-1 (2'-fluoro-6,7-methylenedioxy-2-phenyl-4-quinolone) has been identified as a potent antitumor agent in human hepatocellular carcinoma; however, its role in tumor angiogenesis is unclear. This study investigated the effects of CHM-1 and the mechanisms by which it exerts its antiangiogenic and vascular disrupting properties. Using a xenograft model antitumor assay, we found that CHM-1 significantly inhibits tumor growth and microvessel formation. Flow cytometry, immunofluorescence microscopy, and cell death enzyme-linked immunosorbent assay kit revealed that CHM-1 inhibits growth of human umbilical vein endothelial cells (HUVEC) by induction of apoptotic cell death in a concentration-dependent manner. CHM-1 also suppresses HUVEC migration and capillary-like tube formation. We were able to correlate CHM-1-induced apoptosis in HUVEC with the cleavage of procaspase-3, -7, and -8, as well as with the cleavage of poly(ADP-ribose) polymerase by Western blotting assay. Such sensitization was achieved through up-regulation of death receptor 5 (DR5) but not DR4 or Fas. CHM-1 was also capable of increasing the expression level of p53, and most importantly, the induction of DR5 by CHM-1 was abolished by p53 small interfering RNA. Taken together, the results of this study indicate that CHM-1 exhibits vascular targeting activity associated with the induction of DR5-mediated endothelial cell apoptosis through p53 up-regulation, which suggests its potential as an antivascular and antitumor therapeutic agent.

CHM-1 inhibits hepatocyte growth factor-induced invasion of SK-Hep-1 human hepatocellular carcinoma cells by suppressing matrix metalloproteinase-9 expression.

Clinical observations suggest that hepatocyte growth factor (HGF) can promote invasion and metastasis in hepatocellular carcinoma. In this study, we found that HGF-stimulated invasion of SK-Hep-1 cells, together with increased expression of matrix metalloproteinase (MMP)-9. CHM-1 was identified from 2-phenyl-4-quinolone derivatives to potently inhibit HGF-induced cell invasion, proteolytic activity, and expression of MMP-9. CHM-1 significantly inhibited tyrosine autophosphorylation of c-Met induced by HGF. CHM-1 also suppressed HGF-induced Akt phosphorylation, and NF-kappaB activation, the downstream regulators of HGF/c-Met signaling, resulting in the inhibition of MMP-9. Thus, we suggest that CHM-1 is a potential therapeutic agent against tumor invasion.

N-Sulfonyl-aminobiaryls as Antitubulin Agents and Inhibitors of Signal Transducers and Activators of Transcription 3 (STAT3) Signaling.

A series of N-sulfonyl-aminobiaryl derivatives have been examined as novel antitubulin agents. Compound 21 [N-(4'-cyano-3'-fluoro-biphenyl-2-yl)-4-methoxy-benzenesulfonamide] exhibits remarkable antiproliferative activity against four cancer cell lines (pancreatic AsPC-1, lung A549, liver Hep3B, and prostate PC-3) with a mean GI50 value of 57.5 nM. Additional assays reveal that 21 inhibits not only tubulin polymerization but also the phosphorylation of STAT3 inhibition with an IC50 value of 0.2 µM. Four additional compounds (8, 10, 19, and 35) are also able to inhibit this phosphorylation. This study describes novel N-sulfonyl-aminobiaryl (biaryl-benzenesulfonamides) as potent anticancer agents targeting both STAT3 and tubulin.

In vitro and in vivo anti-tumour effects of MPT0B014, a novel derivative aroylquinoline, and in combination with erlotinib in human non-small-cell lung cancer cells.

BACKGROUND AND PURPOSE: The purpose of the current study was to assess a novel anti-cancer drug, MPT0B014, which is not a substrate for the P-glycoprotein (P-gp) transporter, alone and in combination with erlotinib, against human non-small cell lung cancer (NSCLC). EXPERIMENTAL APPROACH: Cytotoxicity in human NSCLC cell lines was assessed by sulforhodamine B and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Cell cycle phase distributions were estimated with FACScan flow cytometry. Protein expression was detected by Western blotting analysis. Efflux of rhodamine 123 or calcein-acetoxymethylester was used to study the P-gp profile. The A549 xenograft model in mice was used to assess in vivo anti-tumour activity. KEY RESULTS: MPT0B014 showed potent anti-proliferative activity against A549, H1299 and H226 cells. It induced G2/M arrest with down-regulation of Cdc (Tyr15) and Cdc25C, and up-regulation of cyclin B1, phospho-Cdc2 (Thr161) and Aurora A/B. P-gp-overexpressing National Cancer Institute/Adriamycin-Resistant cells were also sensitive to B014. B014-induced loss of Mcl-1 was accompanied by activation of caspases-3, -7, -8 and -9, and initiation of apoptosis. B014 in combination with erlotinib caused significant tumour inhibition in vitro and in vivo. CONCLUSIONS AND IMPLICATIONS: MPT0B014 exerted cytotoxicity against human NSCLC cell lines with little susceptibility to P-gp. Combined with the EGF receptor inhibitor, erlotinib, MPT0B014 exerted significant growth inhibition of A549 cells both in vitro and in vivo. B014 could be useful as an anti-cancer agent.

Synergistic interaction between the HDAC inhibitor, MPT0E028, and sorafenib in liver cancer cells in vitro and in vivo.

PURPOSE: To investigate the antitumor activities of a histone deacetylase (HDAC) inhibitor, MPT0E028, plus sorafenib in liver cancer cells in vitro and in vivo. EXPERIMENTAL DESIGN: Different liver cancer cell lines were exposed to sorafenib in the presence or absence of MPT0E028, and cell viability was determined by MTT assay. Effects of combined treatment on cell cycle and intracellular signaling pathways were assessed by flow cytometry and Western blot analysis. The Hep3B xenograft model was used to examine the antitumor activity in vivo. RESULTS: Our data indicate that sorafenib and MPT0E028 synergistically reduced cell viability in liver cancer cells, and also markedly induced apoptotic cell death in these cells, as evidenced by the cleavage of caspase-3, PARP, and DNA fragmentation. MPT0E028 altered the global modifications of histone and nonhistone proteins regardless of the presence of sorafenib. However, sorafenib blocked MPT0E028-induced Erk activation and its downstream signaling cascades, such as Stat3 phosphorylation (Ser(727)) and Mcl-1 upregulation. Ectopic expression of constitutively active Mek successively reversed the apoptosis triggered by the combined treatment. Pharmacologic inhibition of Mek by PD98059 potentiated MPT0E028-induced apoptosis, suggesting that the synergistic interaction between MPT0E028 and sorafenib occurs at least partly through inhibition of Erk signaling. The data demonstrated that transcriptional activation of fibroblast growth factor receptor 3 (FGFR3) contributes to MPT0E028-mediated Erk phosphorylation. Finally, MPT0E028 plus sorafenib significantly improved the tumor growth delay (TGD) in a Hep3B xenograft model. CONCLUSIONS: These findings suggest that MPT0E028 in combination with sorafenib has significant anti-hepatocellular carcinoma activity in preclinical models, potentially suggesting a novel therapeutic strategy for patients with advanced hepatocellular carcinoma.

A novel action mechanism for MPT0G013, a derivative of arylsulfonamide, inhibits tumor angiogenesis through up-regulation of TIMP3 expression.

Tissue inhibitors of metalloproteinases 3 (TIMP3) were originally characterized as inhibitors of matrix metalloproteinases (MMPs), acting as potent antiangiogenic proteins. In this study, we demonstrated that the arylsulfonamide derivative MPT0G013 has potent antiangiogenic activities in vitro and in vivo viainducing TIMP3 expression. Treatments with MPT0G013 significantly inhibited endothelial cell functions, such as cell proliferation, migration, and tube formation, as well as induced p21 and cell cycle arrest at the G0/G1 phase. Subsequent microarray analysis showed significant induction of TIMP3 gene expression by MPT0G013, and siRNA-mediated blockage of TIMP3 up-regulation abrogated the antiangiogenic activities of MPT0G013 and prevented inhibition of p-AKT and p-ERK proteins. Importantly, MPT0G013 exhibited antiangiogenic activities in in vivo Matrigel plug assays, inhibited tumor growth and up-regulated TIMP3 and p21 proteins in HCT116 mouse xenograft models. These data suggest potential therapeutic application of MPT0G013 for angiogenesis-related diseases such as cancer.

Azaindolylsulfonamides, with a more selective inhibitory effect on histone deacetylase 6 activity, exhibit antitumor activity in colorectal cancer HCT116 cells.

A series of indolylsulfonylcinnamic hydroxamates has been synthesized. Compound 12, (E)-3-(3-((1H-pyrrolo[2,3-b]pyridin-1-yl)sulfonyl)phenyl)-N-hydroxyacrylamide, which has a 7-azaindole core cap, was shown to have antiproliferative activity against KB, H460, PC3, HSC-3, HONE-1, A549, MCF-7, TSGH, MKN45, HT29, and HCT116 human cancer cell lines. Pharmacological studies indicated that 12 functions as a potent HDAC inhibitor with an IC50 value of 0.1 µM. It is highly selective for histone deacetylase 6 (HDAC6) and is 60-fold more active than against HDAC1 and 223-fold more active than against HDAC2. It has a good pharmacokinetic profile with oral bioavailability of 33%. In in vivo efficacy evaluations in colorectal HCT116 xenografts, compound 12 suppresses tumor growth more effectively than SAHA (1, N-hydroxy-N'-phenyloctanediamide) and is therefore seen as a suitable candidate for further investigation.

Dehydrocostuslactone suppresses angiogenesis in vitro and in vivo through inhibition of Akt/GSK-3ß and mTOR signaling pathways.

The traditional Chinese medicine component dehydrocostuslactone (DHC) isolated from Saussurea costus (Falc.) Lipschitz, has been shown to have anti-cancer activity. Angiogenesis is an essential process in the growth and progression of cancer. In this study, we demonstrated, for the first time, the anti-angiogenic mechanism of action of DHC to be via the induction of cell cycle progression at the G0/G1 phase due to abrogation of the Akt/glycogen synthase kinase-3ß (GSK-3ß)/cyclin D1 and mTOR signaling pathway. First, we demonstrated that DHC has an anti-angiogenic effect in the matrigel-plug nude mice model and an inhibitory effect on human umbilical vein endothelial cell (HUVEC) proliferation and capillary-like tube formation in vitro. DHC caused G0/G1 cell cycle arrest, which was associated with the down-regulation of cyclin D1 expression, leading to the suppression of retinoblastoma protein phosphorylation and subsequent inhibition of cyclin A and cdk2 expression. With respect to the molecular mechanisms underlying the DHC-induced cyclin D1 down-regulation, this study demonstrated that DHC significantly inhibits Akt expression, resulting in the suppression of GSK-3ß phosphorylation and mTOR expression. These effects are capable of regulating cyclin D1 degradation, but they were significantly reversed by constitutively active myristoylated (myr)-Akt. Furthermore, the abrogation of tube formation induced by DHC was also reversed by overexpression of Akt. And the co-treatment with LiCl and DHC significantly reversed the growth inhibition induced by DHC. Taken together, our study has identified Akt/GSK-3ß and mTOR as important targets of DHC and has thus highlighted its potential application in angiogenesis-related diseases, such as cancer.

Aciculatin induces p53-dependent apoptosis via MDM2 depletion in human cancer cells in vitro and in vivo.

Aciculatin, a natural compound extracted from the medicinal herb Chrysopogon aciculatus, shows potent anti-cancer potency. This study is the first to prove that aciculatin induces cell death in human cancer cells and HCT116 mouse xenografts due to G1 arrest and subsequent apoptosis. The primary reason for cell cycle arrest and cell death was p53 accumulation followed by increased p21 level, dephosphorylation of Rb protein, PUMA expression, and induction of apoptotic signals such as cleavage of caspase-9, caspase-3, and PARP. We demonstrated that p53 allele-null (-/-) (p53-KO) HCT116 cells were more resistant to aciculatin than cells with wild-type p53 (+/+). The same result was achieved by knocking down p53 with siRNA in p53 wild-type cells, indicating that p53 plays a crucial role in aciculatin-induced apoptosis. Although DNA damage is the most common event leading to p53 activation, we found only weak evidence of DNA damage after aciculatin treatment. Interestingly, the aciculatin-induced downregulation of MDM2, an important negative regulator of p53, contributed to p53 accumulation. The anti-cancer activity and importance of p53 after aciculatin treatment were also confirmed in the HCT116 xenograft models. Collectively, these results indicate that aciculatin treatment induces cell cycle arrest and apoptosis via inhibition of MDM2 expression, thereby inducing p53 accumulation without significant DNA damage and genome toxicity.

Anticancer activity of MPT0E028, a novel potent histone deacetylase inhibitor, in human colorectal cancer HCT116 cells in vitro and in vivo.

Recently, histone deacetylase (HDAC) inhibitors have emerged as a promising class of drugs for treatment of cancers, especially subcutaneous T-cell lymphoma. In this study, we demonstrated that MPT0E028, a novel N-hydroxyacrylamide-derived HDAC inhibitor, inhibited human colorectal cancer HCT116 cell growth in vitro and in vivo. The results of NCI-60 screening showed that MPT0E028 inhibited proliferation in both solid and hematological tumor cell lines at micromolar concentrations, and was especially potent in HCT116 cells. MPT0E028 had a stronger apoptotic activity and inhibited HDACs activity more potently than SAHA, the first therapeutic HDAC inhibitor proved by FDA. In vivo murine model, the growth of HCT116 tumor xenograft was delayed and inhibited after treatment with MPT0E028 in a dose-dependent manner. Based on in vivo study, MPT0E028 showed stronger anti-cancer efficacy than SAHA. No significant body weight difference or other adverse effects were observed in both MPT0E028-and SAHA-treated groups. Taken together, our results demonstrate that MPT0E028 has several properties and is potential as a promising anti-cancer therapeutic drug.

The inhibition of angiogenesis and tumor growth by denbinobin is associated with the blocking of insulin-like growth factor-1 receptor signaling.

Denbinobin, which is a phenanthraquinone derivative present in the stems of Ephemerantha lonchophylla, has been demonstrated to display antitumor activity. Recent reports suggest that the enhanced activity of insulin-like growth factor-1 receptor (IGF-1R) is closely associated with tumor angiogenesis and growth. This study aims at investigating the roles of denbinobin in suppressing these effects and at further elucidating the underlying molecular mechanisms. In the present study, we used an in vivo xenograft model antitumor and the Matrigel implant assays to show that denbinobin suppresses lung adenocarcinoma A549 growth and microvessel formation. Additionally, crystal violet and capillary-like tube formation assays indicated that denbinobin selectively inhibits insulin-like growth factor-1 (IGF-1)-induced proliferation (GI50=1.3×10⁻8 M) and tube formation of human umbilical vascular endothelial cells (HUVECs) without influencing the effect of epidermal growth factor; vascular endothelial growth factor and basic fibroblast growth factor. Furthermore, denbinobin inhibited the IGF-1-induced migration of HUVECs in a concentration-dependent fashion. Western blotting and immunoprecipitation demonstrated that denbinobin causes more efficient inhibition of IGF-1-induced activation of IGF-1R and its downstream signaling targets, including , extracellular signal-regulated kinase, Akt, mTOR, p70S6K, 4EBP and cyclin D1. All of our results provide evidences that denbinobin suppresses the activation of IGF-1R and its downstream signaling pathway, which leads to the inhibition of angiogenesis. Our findings suggest that denbinobin may be a novel IGF-1R kinase inhibitor and has potential therapeutic abilities for angiogenesis-related diseases such as cancer.

Potent anti-inflammatory effects of denbinobin mediated by dual inhibition of expression of inducible no synthase and cyclooxygenase 2.

Inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2) have been suggested to play important roles in various inflammatory diseases. We explored the anti-inflammatory potential of a natural compound, denbinobin (5-hydroxy-3,7-dimethoxy-1,4-phenanthraquinone), by examining its effects on the expression and activity of iNOS and COX-2 in LPS-activated macrophages. Denbinobin markedly decreased the LPS (1 µg/mL)-induced increase in iNOS and COX-2 gene and protein expression, as well as levels of the downstream products NO and prostaglandin E2, in a concentration-dependent manner (0.3-3 µM). In clarifying the mechanisms involved, denbinobin was found not only to inhibit LPS-induced nuclear factor κB (NF-κB) activation, an effect highly correlated with its inhibitory effect on LPS-induced inhibitory κB kinase activation, inhibitory κB degradation, NF-κB phosphorylation, and binding of NF-κB to the κB motif of the iNOS and COX-2 promoters, but also suppressed phosphorylation of mitogen-activated protein kinases. Reporter gene assays and Western blotting revealed that denbinobin significantly suppressed NF-κB activation. Furthermore, denbinobin also downregulated the LPS-mediated CD14/toll-like receptor 4 complex level and TNF-α, IL-1ß, and IL-10 mRNA expression. Our results demonstrate that denbinobin exerts potent anti-inflammatory activity, suggesting that it might provide a new therapeutic approach to inflammatory diseases.

Moscatilin, a bibenzyl derivative from the India orchid Dendrobrium loddigesii, suppresses tumor angiogenesis and growth in vitro and in vivo.

Attacking angiogenesis is considered an effective strategy for controls the expansion and metastasis of tumors and other related-diseases. The aim of this study was to assess the effects of moscatilin, a bibenzyl derivative, on VEGF and bFGF-induced angiogenesis in cultured human umbilical vein endothelial cells (HUVECs) in vitro and in vivo. Moscatilin significantly inhibited growth of lung cancer cell line A549 (NSCLC) and suppressed growth factor-induced neovascularization. In addition, VEGF- and bFGF-induced cell proliferation, migration, and tube formation of HUVECs was markedly inhibited by moscatilin. Western blotting analysis of cell signaling molecules indicated that moscatilin inhibited ERK1/2, Akt, and eNOS signaling pathways in HUVECs. These results suggest that inhibition of angiogenesis by moscatilin may be a major mechanism in cancer therapy.

The indazole derivative YD-3 specifically inhibits thrombin-induced angiogenesis in vitro and in vivo.

Angiogenesis is a process that involves endothelial cell proliferation, migration, invasion, and tube formation, and the inhibition of these processes has implications for angiogenesis-mediated disorders. The purpose of this study was to examine the antiangiogenic efficacy of YD-3 [1-benzyl-3(ethoxycarbonylphenyl)-indazole], a selective thrombin inhibitor, on thrombin-induced endothelial cell proliferation and neoangiogenesis in a murine Matrigel model. First, the effect of YD-3 on angiogenesis was evaluated in vivo using the mouse Matrigel implant model. Plugs treated with 1 and 10 µM of YD-3 inhibited neovascularization induced by thrombin, protease-activated receptor (PAR) 1, and PAR-4, but not by vascular endothelial growth factor, in a concentration-dependent manner over 7 days. These results indicate that YD-3 has specific antiangiogenic activity on thrombin. YD-3 also inhibited (in a concentration-dependent manner) the ability of thrombin, PAR-1, and PAR-4, but not PAR-2, to induce the proliferation of human umbilical vascular endothelial cells, using a [³H]thymidine incorporation assay. YD-3 predominantly inhibited thrombin-induced vascular endothelial growth factor receptor 2 (Flk-1) expression, but not extracellular signal-regulated kinase 1/2 phosphorylation, using Western blot analysis. YD-3 may have benefit in elucidating pathophysiology induced by thrombin-induced angiogenesis.

EPOX inhibits angiogenesis by degradation of Mcl-1 through ERK inactivation.

PURPOSE: Antiangiogenic therapy is considered as an effective strategy for controlling the growth and metastasis of tumors. Among a myriad of biological activities described for xanthone derivatives, the anticancer activity is quite remarkable, but the molecular mechanism is not clearly resolved. In the present study, we investigated the antiangiogenic mechanism of 3,6-di(2,3-epoxypropoxy)xanthone (EPOX), a novel Mcl-1 targeting drug. EXPERIMENTAL DESIGN: To evaluate the antiangiogenic activity of EPOX, we did cell viability, cell cycle, tube formation assay in vitro, and Matrigel plug assay in vivo. To evaluate the effect of EPOX on the endothelial signaling pathway, we did immunoblotting, immunoprecipitation, and immunofluorescence analysis. Intracellular glutathione levels were determined with the use of monochlorobimane, a glutathione-specific probe. RESULTS: EPOX induced endothelial cell apoptosis in association with proteasome-dependent Mcl-1 degradation. Down-regulation of Mcl-1 resulted in an increase in Mcl-1-free Bim, activation of Bax, and then signaling of mitochondria-mediated apoptosis. Additionally, glutathione depletion and extracellular signal-regulated kinase (ERK) inactivation was observed in EPOX-treated cells. Glutathione supplementation reversed the inhibitory effects of EPOX on ERK, which increases the phosphorylation of Mcl-1 at T(163.) Overexpression of mitogen-activated protein/ERK kinase (MEK) partially reversed the effect of EPOX on Mcl-1 dephosphorylation, ubiquitination, and degradation, further implicating ERK in the regulation of Mcl-1 stability. CONCLUSIONS: This study provides evidence that EPOX induces glutathione depletion, ERK inactivation, and Mcl-1 degradation on endothelial cells, which leads to inhibition of angiogenesis. Our results suggest that EPOX is a novel antiangiogenic agent, making it a promising lead compound for further development in the treatment of angiogenesis-related pathologies.

Induction of cyclooxygenase-2 expression in human tracheal smooth muscle cells by interleukin-1beta: involvement of p42/p44 and p38 mitogen-activated protein kinases and nuclear factor-kappaB.

Interleukin-1beta (IL-1beta) has been recognized as a potent stimulus for the synthesis of prostaglandin (PG), which has been implicated in inflammatory responses of the airways. However, the mechanisms underlying IL-1beta-induced cyclooxygenase (COX) expression and PGE(2) synthesis via activation of p42/p44 and p38 mitogen-activated protein kinases (MAPKs) in human tracheal smooth muscle cells (HTSMCs) are not completely understood. We found that IL-1beta increased COX-2 expression and PGE(2) synthesis in time- and concentration-dependent manners. Both specific phosphatidylcholine-phospholipase C inhibitor (D609) and protein kinase C inhibitor (GF109203X) attenuated IL-1beta-induced responses in HTSMCs. IL-1beta-induced COX-2 expression and PGE(2) synthesis were also inhibited by an inhibitor of MEK1/2 (PD98059) and inhibitors of p38 MAPK (SB203580 and SB202190), respectively, suggesting the involvement of p42/p44 and p38 MAPKs in these responses. This hypothesis was further supported by the transient activation of p42/p44 and p38 MAPKs induced by IL-1beta. Furthermore, IL-1beta-induced activation of nuclear factor-kappaB (NF-kappaB) was inversely correlated with the degradation of IkappaB-alpha in HTSMCs. IL-1beta-induced COX-2 expression and PGE(2) synthesis were inhibited by the NF-kappaB inhibitor pyrrolidinedithiocarbamate. These findings suggest that the expression of COX-2 is correlated with the release of PGE(2) from IL-1beta-challenged HTSMCs, which is mediated, at least in part, through p42/p44 and p38 MAPKs and NF-kappaB signaling pathways in HTSMCs.