Metallothioneins 1 and 2 attenuate peroxynitrite-induced oxidative stress in Parkinson disease

We have examined potent peroxynitrite ion (ONOO-) generator 3-morpholinosydnonimine (SIN-1)-induced neurotoxicity in control wild-type (control(wt)) mice, metallothionein double knockout (MT(dko)) mice, metallothionein-transgenic (MT(trans)) mice, and in cultured human dopaminergic (SK-N-SH) neurons to determine the neuroprotective potential of metallothionein against ONOO(-)-induced neurodegeneration in Parkinson disease (PD). SIN-1-induced lipid peroxidation, reactive oxygen species synthesis, caspase-3 activation, and apoptosis were attenuated by metallothionein gene overexpression and augmented by metallothionein gene down-regulation. A progressive nigrostriatal dopaminergic neurodegeneration in weaver mutant (wv/wv) mice was associated with enhanced nitrite ion synthesis, metallothionein down-regulation, and significantly reduced dopamine synthesis and 18F-DOPA uptake as determined by high-resolution micropositron emission tomography neuroimaging. The striatal (18)F-DOPA uptake was significantly higher in MT(trans) mice than in MT(dko) and alpha-synuclein knockout (alpha-Syn(ko)) mice. These observations provide further evidence that nitric oxide synthase activation and ONOO- synthesis may be involved in the etiopathogenesis of PD, and that metallothionein gene induction may provide neuroprotection.     

Mutation of the E6-AP ubiquitin ligase reduces nuclear inclusion frequency while accelerating polyglutamine-induced pathology in SCA1 mice

Mutant ataxin-1, the expanded polyglutamine protein causing spinocerebellar ataxia type 1 (SCA1), aggregates in ubiquitin-positive nuclear inclusions (NI) that alter proteasome distribution in affected SCA1 patient neurons. Here, we observed that ataxin-1 is degraded by the ubiquitin-proteasome pathway. While ataxin-1 [2Q] and mutant ataxin-1 [92Q] are polyubiquitinated equally well in vitro, the mutant form is three times more resistant to degradation. Inhibiting proteasomal degradation promotes ataxin-1 aggregation in transfected cells. And in mice, Purkinje cells that express mutant ataxin-1 but not a ubiquitin-protein ligase have significantly fewer NIs. Nonetheless, the Purkinje cell pathology is markedly worse than that of SCA1 mice. Taken together, NIs are not necessary to induce neurodegeneration, but impaired proteasomal degradation of mutant ataxin-1 may contribute to SCA1 pathogenesis.     

Distribution of Coenzyme Q Homologues in Brain

Ubiquinone (coenzyme Q₁₀), in addition to its function as an electron and proton carrier in mitochondrial electron transport coupled to ATP synthesis, acts in its reduced form (ubiquinol) as an antioxidant, inhibiting lipid peroxidation in biological membranes and protecting mitochondrial inner-membrane proteins and DNA against oxidative damage accompanying lipid peroxidation. Tissue ubiquinone levels are subject to regulation by physiological factors that are related to the oxidative activity of the organism: they increase under the influence of oxidative stress, e.g. physical exercise, cold adaptation, thyroid hormone treatment, and decrease during aging. In the present study, coenzyme Q homologues were separated and quantified in the brains of mice, rats, rabbits, and chickens using high-performance liquid chromatography. In addition, the coenzyme Q homologues were measured in cells such as NG-108, PC-12, rat fetal brain cells and human SHSY-5Y and monocytes. In general, Q₁ content was the lowest among the coenzyme homologues quantified in the brain. Q₉ was not detectable in the brains of chickens and rabbits, but was present in the brains of rats and mice. Q₉ was also not detected in human cell lines SHSY-5Y and monocytes. Q₁₀ was detected in the brains of mice, rats, rabbits, and chickens and in cell lines. Since both coenzyme Q and vitamin E are antioxidants, and coenzyme Q recycles vitamins E and C, vitamin E was also quantified in mice brain using HPLC-electrochemical detector (ECD). The quantity of vitamin E was lowest in the substantia nigra compared with the other brain regions. This finding is crucial in elucidating ubiquinone function in bioenergetics; in preventing free radical generation, lipid peroxidation, and apoptosis in the brain; and as a potential compound in treating various neurodegenerative disorders.     

In Vitro Release of Endogenous Dopamine from the Striatum of the Weaver Mutant Mouse

The weaver mutant mouse has a genetically determined defect in the nigrostriatal dopaminergic system. The present study was undertaken to test the hypothesis that in the weaver mutant mouse, striatal nerve terminals undergo compensatory changes in response to this deficiency. To test this hypothesis, we studied the basal and stimulated release of dopamine from striatal slices of weaver mutant mice and matched controls. By using a superfusion system and concentrating the superfusate by passage over alumina, resting dopamine release could be determined in the weaver mutant despite the fact that striatal tissue content of dopamine in these mice is reduced by greater than 75% compared with control mice. Fractional resting release of dopamine in weaver striatal slices was significantly elevated compared with that in controls, suggesting that the release mechanisms in the weaver may be adapting to overcome the dopamine deficit. Potassium-evoked release (24 and 48 mM potassium) was not significantly different between the two genotypes. In contrast, amphetamine-evoked release (1 microM) was significantly greater in the weaver mice than in controls. In both genotypes, release evoked by amphetamine was completely inhibited by cocaine, implicating the dopamine uptake carrier in this release process. These findings suggest that fundamental differences in dopamine release mechanisms exist between weaver and control mice and support the hypothesis that compensatory mechanisms may develop in neurons in response to dopamine deficits.     

Effect of dopaminergic neurotoxin MPTP/MPP+ on coenzyme Q content

Coenzyme Q10, an endogenous lipophilic antioxidant, plays an indispensable role in ATP synthesis. The therapeutic value of coenzyme Q10 in Parkinson's disease and other neurodegenerative disorders is still being tested and the preliminary results are promising. The 1-methyl-4-phenyl-1, 2, 3, 6 tetrahydropyridine (MPTP)-treated mouse is a valid and accepted animal model for Parkinson's disease. 1-methyl-4-phenylpyridinium (MPP(+)) is an active toxic metabolite of MPTP. MPP(+) and MPTP are known to induce oxidative stress and mitochondrial dysfunction. However, the effect of MPP(+) and MPTP on coenzyme Q is not clearly understood. The present study investigated the in vitro and in vivo effect of MPP(+) and MPTP on coenzyme Q content. Coenzyme Q content was measured using HPLC-UV detection methods. In the in vitro studies, MPP(+) (0-50 microM) was incubated with SH-SY5Y human neuroblastoma cells and NG-108-15 (mouse/rat, neuroblastomaxglioma hybrid) cells. MPP(+) concentration dependently increased coenzyme Q10 content in SH-SY5Y cells. In NG-108-15 cells, MPP(+) concentration dependently increased both coenzyme Q9 and Q10 content. In the in vivo study, mice were administered with MPTP (30 mg/kg, twice 16 h apart) and sacrificed one week after the last administration. Administration of MPTP to mice significantly increased coenzyme Q9 and coenzyme Q10 levels in the nigrostriatal tract. However, MPTP did not affect the coenzyme Q content in the cerebellum, cortex and pons. This study demonstrated that MPP(+)/MPTP significantly affected the coenzyme Q content in the SH-SY5Y and NG-108 cells and in the mouse nigrostriatal tract.     

Identification of natural compounds targeting Annexin A2 with an anti-cancer effect

Annexin A2, a multifunctional tumor associated protein, promotes nuclear factor-kappa B (NF-κB) activation by interacting with NF-κB p50 subunit and facilitating its nuclear translocation. Here we demonstrated that two ginsenosides Rg5 (G-Rg5) and Rk1 (G-Rk1), with similar structure, directly bound to Annexin A2 by molecular docking and cellular thermal shift assay. Both Rg5 and Rk1 inhibited the interaction between Annexin A2 and NF-κB p50 subunit, their translocation to nuclear and NF-κB activation. Inhibition of NF-κB by these two ginsenosides decreased the expression of inhibitor of apoptosis proteins (IAPs), leading to caspase activation and apoptosis. Over expression of K302A Annexin A2, a mutant version of Annexin A2, which fails to interact with G-Rg5 and G-Rk1, effectively reduced the NF-κB inhibitory effect and apoptosis induced by G-Rg5 and G-Rk1. In addition, the knockdown of Annexin A2 largely enhanced NF-κB activation and apoptosis induced by the two molecules, indicating that the effects of G-Rg5 and G-Rk1 on NF-κB were mainly mediated by Annexin A2. Taken together, this study for the first time demonstrated that G-Rg5 and G-Rk1 inhibit tumor cell growth by targeting Annexin A2 and NF-κB pathway, and G-Rg5 and G-Rk1 might be promising natural compounds for targeted cancer therapy.     

发酵生产辅酶Q10高产菌株的选育

以实验室保存的类球红细菌(Rhodobacter sphaeroides)JDW61为出发菌株,考察了紫外、紫外结合氯化锂和亚硝基胍对菌株产生辅酶Q10能力的诱变效应,并结合辅酶Q10的合成途径设计了快速筛选辅酶Q10高产菌株的模型,获得一株辅酶Q10产量提高的突变株CP222,该菌株摇瓶发酵的辅酶Q10产量为276.14mg·L-1,较出发菌株提高了190%,并且遗传性能稳定。     

Layer-specific innervation of the dopamine-deficient frontal cortex in weaver mutant mice by grafted mesencephalic dopaminergic neurones

Summary The dopamine innervation of the frontal cortex originates in the A9 and A10 mesencephalic dopamine cell groups. In weaver mutant mice, there is a 77% frontocortical dopamine deficiency associated with losses of dopamine neurones in areas A9 and A10. The dopamine-depleted cortical areas of weaver mutant mice are receptive to reinnervation by afferent fibres originating in dopamine-containing mesencephalic grafts from normal donor embryos. In the anteromedial frontal lobe, reinnervation by tyrosine hydroxylase immunoreactive fibres is largely confined to the basal cortical layers whereas in the anterior cingulate cortex, tyrosine hydroxylase immunoreactive fibres also occupy superficial layers, including the molecular layer. Normally, the dopaminergic innervation of the anteromedial frontal lobe is distributed among the basal cortical layers (IV–VI), and the dopaminergic innervation of the cingulate cortex occupies both basal and superficial cortical layers. The pattern of innervation following transplantation indicates that, in repopulating dopamine-deficient cortical areas of recipient weaver mutants, graft-derived dopamine fibres show a preference for those layers which are normally invested by dopamine afferents.     

Effects of ubiquinones on spontaneous membrane hyperpolarizations in a cloned monkey kidney cell line

The effects of ubiquinones on spontaneous membrane hyperpolarizations in JTC-12 cells were examined. There were three types of spontaneous hyperpolarizations; rhythmic, sporadic and oscillatory types. The oscillatory type was not observed in the standard medium, whereas it was observed in sodium-free medium or in the medium containing 300 nM coenzyme Q10. The number of the cells showing spontaneous hyperpolarizations significantly increased in the medium containing coenzyme Q10 (47.7%) as compared to the control (18.9%). However, coenzyme Q1 (500 nM) showed no effects.     

Pulmonary Inflammation Is Regulated by the Levels of the Vesicular Acetylcholine Transporter

Acetylcholine (ACh) plays a crucial role in physiological responses of both the central and the peripheral nervous system. Moreover, ACh was described as an anti-inflammatory mediator involved in the suppression of exacerbated innate response and cytokine release in various organs. However, the specific contributions of endogenous release ACh for inflammatory responses in the lung are not well understood. To address this question we have used mice with reduced levels of the vesicular acetylcholine transporter (VAChT), a protein required for ACh storage in secretory vesicles. VAChT deficiency induced airway inflammation with enhanced TNF-α and IL-4 content, but not IL-6, IL-13 and IL-10 quantified by ELISA. Mice with decreased levels of VAChT presented increased collagen and elastic fibers deposition in airway walls which was consistent with an increase in inflammatory cells positive to MMP-9 and TIMP-1 in the lung. In vivo lung function evaluation showed airway hyperresponsiveness to methacholine in mutant mice. The expression of nuclear factor-kappa B (p65-NF-kB) in lung of VAChT-deficient mice were higher than in wild-type mice, whereas a decreased expression of janus-kinase 2 (JAK2) was observed in the lung of mutant animals. Our findings show the first evidence that cholinergic deficiency impaired lung function and produce local inflammation. Our data supports the notion that cholinergic system modulates airway inflammation by modulation of JAK2 and NF-kB pathway. We proposed that intact cholinergic pathway is necessary to maintain the lung homeostasis.     

Effects of coenzyme Q10 on the heart ultrastructure and nitric oxide synthase during hyperthyroidism

Coenzyme Q10 is an important component of mitochondrial electron transport chain and antioxidant. Hyperthyroidism manifests hyperdynamic circulation with increased cardiac output, increased heart rate and decreased peripheral resistance. The heart is also under the oxidative stress in the hyperthyroidism. The aim of this study was to examine both how the coenzyme Q10 can affect heart ultrastructure in the hyperthyroidism and how the relationship between nitric oxide synthase (NOS) and heart damage and coenzyme Q10. Swiss Black C57 mice received 5 mg/kg L-thyroxine. Coenzyme Q10 (1.5 mg/kg) and L-thyroxine together was given to second group mice. Coenzyme Q10 and serum physiologic were applied to another two groups, respectively. All treatments were performed daily for 15 days by gavage. Free triiodothyronine and thyroxine were increased in two groups given L-thyroxine; thyroid-stimulating hormone level did not change. Hyperthyroid heart showed an increased endothelial NOS (eNOS) and inducible NOS (iNOS) immunoreactivity in the tissue. Coenzyme Q10 administration decreased these NOS immunoreactivities in the hyperthyroid animals. Cardiomyocytes of the hyperthyroid animals was characterized by abnormal shape and invaginated nuclei, and degenerative giant mitochondria. Desmosome plaques reduced in density. In hyperthyroid mice given coenzyme Q10, the structural disorganization and mitochondrial damage regressed. However, hearts of healthy mice given coenzyme Q10 displayed normal ultrastructure, except for increased mitochondria and some of them were partially damaged. Coenzyme Q10 increased the glycogen in the cardiomyocytes. In conclusion, coenzyme Q10 administration can prevent the ultrastructural disorganization and decrease the iNOS and eNOS increment in the hyperthyroid heart.     

Glycine- and proline-rich glycoprotein regulates the balance between cell proliferation and apoptosis for ACF formation in 1,2-dimethylhydrazine-treated A/J mice

The objective of this study was to investigate the chemopreventive potentials of glycine- and proline-rich glycoprotein (SNL glycoprotein, 150-kDa) isolated from Solanum nigrum Linne on formation of colonic aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH, 20 mg/kg) in A/J mice. Administration of SNL glycoprotein inhibited phosphorylation of extracellular signal-regulated kinase (ERK), expression of colonic proliferating cell nuclear antigen (PCNA), and frequency of colonic ACF in DMH-stimulated mice colon carcinogenesis. In addition, SNL glycoprotein increased expression of cyclin-dependent kinase inhibitors (p21^WAF/Cip1 and p27^Kip1), whereas reduced expression of precursor form of apoptosis-related proteins [pro-caspase-3 and pro-poly(ADP-ribose)polymerase (PARP)] in the mice. Interestingly, the results in this study revealed that SNL glycoprotein has suppressive effects on activity of nuclear factor-kappa B (NF-κB), whereas it has stimulatory effect on the expression of p53, accompanying inhibitory effects on expression of NF-κBp50, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in DMH-stimulated ACF formation. Also, SNL glycoprotein has inhibitory effects on the formation of thiobarbituric acid reactive substances (TBARS), on the production of inducible nitric oxide (NO), and on the release of lactate dehydrogenase (LDH) in the mice plasma. Collectively, our findings in this study suggest that SNL glycoprotein has chemopreventive activity via modulation of cell proliferation and apoptosis in DMH-treated A/J mice.     

Tumor necrosis factor (TNF)-mediated neuroprotection against glutamate-induced excitotoxicity is enhanced by N-methyl-D-aspartate receptor activation. Essential role of a TNF receptor 2-mediated phosphatidylinositol 3-kinase-dependent NF-kappa B pathway

We have previously shown that two tumor necrosis factor (TNF) receptors (TNFR) exhibit antagonistic functions during neurodegenerative processes in vivo with TNFR1 aggravating and TNFR2 reducing neuronal cell loss, respectively. To elucidate the neuroprotective signaling pathways of TNFR2, we investigated glutamate-induced excitotoxicity in primary cortical neurons. TNF-expressing neurons from TNF-transgenic mice were found to be strongly protected from glutamate-induced apoptosis. Neurons from wild type and TNFR1(-/-) mice prestimulated with TNF or agonistic TNFR2-specific antibodies were also resistant to excitotoxicity, whereas TNFR2(-/-) neurons died upon glutamate and/or TNF exposures. Both protein kinase B/Akt and nuclear factor-kappa B (NF-kappa B) activation were apparent upon TNF treatment. Both TNFR1 and TNFR2 induced the NF-kappa B pathway, yet with distinguishable kinetics and upstream activating components, TNFR1 only induced transient NF-kappa B activation, whereas TNFR2 facilitated long term phosphatidylinositol 3-kinase-dependent NF-kappa B activation strictly. Glutamate-induced triggering of the ionotropic N-methyl-D-aspartate receptor was required for the enhanced and persistent phosphatidylinositol 3-kinase-dependent NF-kappa B activation by TNFR2, indicating a positive cooperation of TNF and neurotransmitter-induced signal pathways. TNFR2-induced persistent NF-kappa B activity was essential for neuronal survival. Thus, the duration of NF-kappa B activation is a critical determinant for sensitivity toward excitotoxic stress and is dependent on a differential upstream signal pathway usage of the two TNFRs.     

Protective up-regulation of CK2 by mutant huntingtin in cells co-expressing NMDA receptors

Huntington's disease is caused by a polyglutamine expansion in the huntingtin (htt) protein, and previous data indicate that over-activation of NMDA receptors (NMDARs) may be involved in the selective degeneration of cells expressing NR1/NR2B NMDARs. We used Kinetworks™ multi-immunoblotting screens to examine expression of 76 protein kinases, 18 protein phosphatases, 25 heat shock/stress proteins, and 27 apoptosis proteins in human embryonic kidney 293 cells transfected with NR1/NR2B and htt containing 15 (htt-15Q; wild-type) or 138 (htt-138Q; mutant) glutamine repeats. Follow-up experiments revealed several proteins involved in the heat-shock response pathway to be up-regulated in the soluble fraction from cells expressing htt-138Q, including protein phosphatase 5 and cyclin-dependent kinase 5. Increased expression in the soluble fraction of htt-138Q-expressing cells was also noted for the stress- and calcium-activated protein-serine/threonine kinase casein kinase 2, a change which was confirmed in striatal tissue of yeast artificial chromosome transgenic mice expressing full-length mutant htt. Inhibition of casein kinase 2 activity in cultured striatal neurons from these mice significantly exacerbated NMDAR-mediated toxicity, as assessed by labeling of apoptotic nuclei. Our findings are consistent with up-regulation of components of the stress response pathway in the presence of polyglutamine-expanded htt and NR1/NR2B which may reflect an attempt at the cellular level to ameliorate the detrimental effects of mutant htt expression.     

Ontogeny of the cell adhesion molecule L1 in the cerebellum of weaver and reeler mutant mice

The ontogeny of cell adhesion molecule L1 in cerebellum was quantitatively assessed in weaver and reeler mutant mice and in heterozygous litter-mate controls. In the latter the concentration and the amount of L1 both increased from the first postnatal week to become maximum at the second. In contrast, in the weaver and reeler neurologic mutant mice, L1 decreased steadily. The L1 concentration and the amount of L1 was lower in the cerebellum of homozygous mutant mice than in litter-mate controls. The findings are consistent with L1 being a component of axonal plasma membranes. However, no evidence was found of any direct effect of thewv andrl phenotypes on L1 expression.     

Dopamine Transporter-Dependent and -Independent Endogenous Dopamine Release from Weaver Mouse Striatum In Vitro

Abstract: The weaver mutant mouse (wv/wv) has an ～70% loss of nigrostriatal dopamine (DA) neurons, but the fractional DA release evoked by amphetamine (but not a high potassium level) has been shown to be greater from striatal slices of the weaver compared with +/+ mice. In the present work we tested the hypothesis that fractional DA release from weaver striatum would be greater when release was mediated by the DA transporter. Serotonin (5-HT)-stimulated fractional DA release was greater from weaver than from +/+ striatum. The release evoked by 5-HT in the presence of 10 µM nomifensine (an antagonist of the DA transporter) was less than in its absence, but the difference between weaver and +/+ striatum remained. In the presence of nomifensine, 1-(m-chlorophenyl)biguanide, classified as a 5-HT₃ agonist, also induced a greater fractional release from weaver compared with +/+ striatum. When veratridine was used at a low concentration (1 µM), the fractional evoked release of DA was higher from the weaver in the presence and absence of nomifensine. These findings suggest that the reason for the difference in the responsiveness of the two genotypes to these release-inducing agents is not related to DA transporter function.     

GPR30 contributes to estrogen-induced thymic atrophy

The mechanisms by which prolonged estrogen exposures, such as estrogen therapy and pregnancy, reduce thymus weight, cellularity, and CD4 and CD8 phenotype expression, have not been well defined. In this study, the roles played by the membrane estrogen receptor, G protein-coupled receptor 30 (GPR30), and the intracellular estrogen receptors, estrogen receptor alpha (ERalpha) and beta (ERbeta), in 17beta-estradiol (E2)-induced thymic atrophy were distinguished by construction and the side-by-side comparison of GPR30-deficient mice with ERalpha and ERbeta gene-deficient mice. Our study shows that whereas ERalpha mediated exclusively the early developmental blockage of thymocytes, GPR30 was indispensable for thymocyte apoptosis that preferentially occurs in T cell receptor beta chain(-/low) double-positive thymocytes. Additionally, G1, a specific GPR30 agonist, induces thymic atrophy and thymocyte apoptosis, but not developmental blockage. Finally, E2 treatment attenuates the activation of nuclear factor-kappa B in CD25(-)CD4(-)CD8(-) double-negative thymocytes through an ERalpha-dependent yet ERbeta- and GPR30-independent pathway. Differential inhibition of nuclear factor-kappaB by ERalpha and GPR30 might underlie their disparate physiological effects on thymocytes. Our study distinguishes, for the first time, the respective contributions of nuclear and membrane E2 receptors in negative regulation of thymic development.     

Redox state of glutathione and thioredoxin in differentiation and apoptosis

This study was organized by Professor Karl Folkers with the objective of finding derivatives of coenzyme Q which could be more effectively absorbed and would give better biomedical effects. In this series all the compounds are 2,3 dimethoxy, 5 methyl p benzoquinone with modified side chains in the 6 position. The modifications are primarily changes in chain length, unsaturation, methyl groups and addition of terminal phenyl groups. The test system evaluates the growth of serum deficient HL60, 3T3 and HeLa cells in the presence of coenzyme Q10 or coenzyme Q analogs. Short chain coenzyme Q homologues such as coenzyme Q2 give poor growth but compounds with saturated short aliphatic side chains from C10 to C18 produce good growth. Introduction of a single double bond at the 2' or 8' position in the aliphatic chain retains growth stimulation at low concentration but introduces inhibition at higher concentration. Introduction of a 3' methyl group in addition to the 2' enyl site in the side chain decreases the growth response and maintains inhibition. Addition of a terminal phenyl group to the side chain from C5 to C10 can produce analogs which give strong stimulation or strong inhibition of growth. The action of the analogs is in addition to the natural coenzyme Q in the cell and is not based on restoration of activity after depletion of normal coenzyme Q. The effects may be based on any of the sites in the cell where coenzyme Q functions. For example, coenzyme Q2 is known to decrease mitochondrial membrane potential whereas the analog with a 10C aliphatic side chain increases potential. Both of these compounds stimulate plasma membrane electron transport. Inhibition of apoptosis by coenzyme Q may also increase net cell proliferation and the 10C analog inhibits the permeability transition pore.     

MicroRNA 421 suppresses DPC4/Smad4 in pancreatic cancer

Dihydroavenanthramide D (DHAvD) is a synthetic analog to naturally occurring avenanthramide, which is the active component of oat. Previous study demonstrates that DHAvD strongly inhibits activation of nuclear factor-kappa B (NF-κB), which is a major component in cancer cell invasion. The present study investigated whether DHAvD can modulate MMP-9 expression and cell invasion in MCF-7 human breast cancer cells. MMP-9 expression and cell invasion in response to 12-O-tetradecanoylphorbol-13-acetate (TPA) was increased, whereas these inductions were muted by DHAvD. DHAvD also suppressed activation of mitogen-activated protein kinase (MAPK), and MAPK-mediated nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) activations in TPA-treated MCF-7 cells. The results indicate that DHAvD-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the MAPK/NF-κB and MAPK/AP-1 pathways in MCF-7 cells. DHAvD may have potential value in breast cancer metastasis.