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1.
J Neuroinflammation ; 16(1): 186, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601232

RESUMO

BACKGROUND: Blood markers indicative of neurodegeneration (neurofilament light chain; NFL), Alzheimer's disease amyloid pathology (amyloid-ß; Aß), and neuroinflammation (kynurenine pathway; KP metabolites) have been investigated independently in neurodegenerative diseases. However, the association of these markers of neurodegeneration and AD pathology with neuroinflammation has not been investigated previously. Therefore, the current study examined whether NFL and Aß correlate with KP metabolites in elderly individuals to provide insight on the association between blood indicators of neurodegeneration and neuroinflammation. METHODS: Correlations between KP metabolites, measured using liquid chromatography and gas chromatography coupled with mass spectrometry, and plasma NFL and Aß concentrations, measured using single molecule array (Simoa) assays, were investigated in elderly individuals aged 65-90 years, with normal global cognition (Mini-Mental State Examination Score ≥ 26) from the Kerr Anglican Retirement Village Initiative in Ageing Health cohort. RESULTS: A positive correlation between NFL and the kynurenine to tryptophan ratio (K/T) reflecting indoleamine 2,3-dioxygenase activity was observed (r = .451, p < .0001). Positive correlations were also observed between NFL and kynurenine (r = .364, p < .0005), kynurenic acid (r = .384, p < .0001), 3-hydroxykynurenine (r = .246, p = .014), anthranilic acid (r = .311, p = .002), and quinolinic acid (r = .296, p = .003). Further, significant associations were observed between plasma Aß40 and the K/T (r = .375, p < .0005), kynurenine (r = .374, p < .0005), kynurenic acid (r = .352, p < .0005), anthranilic acid (r = .381, p < .0005), and quinolinic acid (r = .352, p < .0005). Significant associations were also observed between plasma Aß42 and the K/T ratio (r = .215, p = .034), kynurenic acid (r = .214, p = .035), anthranilic acid (r = .278, p = .006), and quinolinic acid (r = .224, p = .027) in the cohort. On stratifying participants based on their neocortical Aß load (NAL) status, NFL correlated with KP metabolites irrespective of NAL status; however, associations between plasma Aß and KP metabolites were only pronounced in individuals with high NAL while associations in individuals with low NAL were nearly absent. CONCLUSIONS: The current study shows that KP metabolite changes are associated with biomarker evidence of neurodegeneration. Additionally, the association between KP metabolites and plasma Aß seems to be NAL status dependent. Finally, the current study suggests that an association between neurodegeneration and neuroinflammation manifests in the periphery, suggesting that preventing cytoskeleton cytotoxicity by KP metabolites may have therapeutic potential.

2.
Neurobiol Aging ; 80: 11-20, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31055163

RESUMO

Chronic kynurenine pathway (KP) activation is implicated in Alzheimer's disease (AD) pathophysiology and results in quinolinic acid-induced excitotoxic stimulation of the N-methyl-D-aspartate receptor. However, most studies focus on plasma and it is unclear if peripheral concentrations reflect brain concentrations and how these may correlate to the AD biomarkers amyloid-ß, total-tau (t-tau), or phosphorylated-tau (p-tau). We characterized the KP in matched plasma and cerebrospinal fluid (CSF) samples from 20 AD patients and 18 age-matched control subjects. Plasma concentrations of kynurenine (KYN), 3-hydroxykynurenine, anthranilic acid, picolinic acid, and neopterin significantly correlated with their respective CSF levels. In patients with AD, plasma KYN (r = -0.48, p = 0.033) and picolinic acid (r = -0.57, p = 0.009) inversely correlated with CSF p-tau and t-tau, respectively. Furthermore, in AD CSF, increased 3-hydroxykynurenine/KYN ratio correlated with t-tau (r = 0.58, p = 0.009) and p-tau (r = 0.52, p = 0.020). These data support KP involvement in AD pathogenesis and add to the case for the therapeutic modulation of the KP in AD.

3.
Biomacromolecules ; 20(5): 2148-2158, 2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-30995832

RESUMO

Poly(amidoamine) dendrimer (PAMAM) is well-known for its high efficiency as a drug delivery vehicle. However, the intrinsic cytotoxicity and lack of a detectable signal to facilitate tracking have impeded its practical applications. Herein, we have developed a novel label-free fluorescent and biocompatible PAMAM derivative by simple surface modification of PAMAM using acetaldehyde. The modified PAMAM possessed a strong green fluorescence, which was generated by the C=N bonds of the resulting Schiff Bases via n-π* transition, while the intrinsic cytotoxicity of PAMAM was simultaneously ameliorated. Through further PEGylation, the fluorescent PAMAM demonstrated excellent intracellular tracking in human melanoma SKMEL28 cells. In addition, our PEGylated fluorescent PAMAM derivative achieved enhanced loading and delivery efficiency of the anticancer drug doxorubicin (DOX) compared to the original PAMAM. Importantly, the accelerated kinetics of DOX-encapsulated fluorescent PAMAM nanocomposites in an acidic environment facilitated intracellular drug release, which demonstrated comparable cytotoxicity to that of the free-form doxorubicin hydrochloride (DOX·HCl) against melanoma cells. Overall, our label free fluorescent PAMAM derivative offers a new opportunity of traceable and controlled delivery for DOX and other drugs of potential clinical importance.

4.
Neurotox Res ; 35(3): 530-541, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30666558

RESUMO

Upregulation of the kynurenine pathway (KP) of tryptophan metabolism is commonly observed in neurodegenerative disease. When activated, L-kynurenine (KYN) increases in the periphery and central nervous system where it is further metabolised to other neuroactive metabolites including 3-hydroxykynurenine (3-HK), kynurenic acid (KYNA) and quinolinic acid (QUIN). Particularly biologically relevant metabolites are 3-HK and QUIN, formed downstream of the enzyme kynurenine 3-monooxygenase (KMO) which plays a pivotal role in maintaining KP homeostasis. Indeed, excessive production of 3-HK and QUIN has been described in neurodegenerative disease including Alzheimer's disease and Huntington's disease. In this study, we characterise KMO activity in human primary neurons and identified new mechanisms by which KMO activation mediates neurotoxicity. We show that while transient activation of the KP promotes synthesis of the essential co-enzyme nicotinamide adenine dinucleotide (NAD+), allowing cells to meet short-term increased energy demands, chronic KMO activation induces production of reactive oxygen species (ROS), mitochondrial damage and decreases spare-respiratory capacity (SRC). We further found that these events generate a vicious-cycle, as mitochondrial dysfunction further shunts the KP towards the KMO branch of the KP to presumably enhance QUIN production. These mechanisms may be especially relevant in neurodegenerative disease as neurons are highly sensitive to oxidative stress and mitochondrial impairment.


Assuntos
Sobrevivência Celular/fisiologia , Quinurenina 3-Mono-Oxigenase/metabolismo , Mitocôndrias/metabolismo , Neurônios/metabolismo , Estresse Oxidativo/fisiologia , Trifosfato de Adenosina/metabolismo , Encéfalo/metabolismo , Células HEK293 , Humanos , Ácido Cinurênico/metabolismo , Cinurenina/análogos & derivados , Cinurenina/metabolismo , Potencial da Membrana Mitocondrial/fisiologia , Doenças Mitocondriais/metabolismo , NAD/metabolismo , Cultura Primária de Células , Ácido Quinolínico/metabolismo , Espécies Reativas de Oxigênio/metabolismo
5.
Neural Regen Res ; 13(12): 2073-2076, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30323124

RESUMO

Chronic induction of the kynurenine pathway (KP) contributes to neuroinflammation by producing the excitotoxin quinolinic acid (QUIN). This has led to significant interest in the development of inhibitors of this pathway, particularly in the context of neurodegenerative disease. However, acute spinal cord injury (SCI) also results in deleterious increases in QUIN, as secondary inflammatory processes mediated largely by infiltrating macrophages, become predominant. QUIN mediates significant neurotoxicity primarily by excitotoxic stimulation of the N-methyl-D-aspartate receptor, but other mechanisms of QUIN toxicity are known. More recent focus has assessed the contribution that neuroinflammation and modulations in the KP make in mood and psychiatric disorders with recent studies linking inflammation and modulations in the KP, to impaired cognitive performance and depressed mood in SCI patients. We hypothesize that these findings suggest that in SCI, inhibition of QUIN production and other metabolites, may have multiple therapeutic modalities and further studies investigating this are warranted. However, for central nervous system-based conditions, achieving good blood-brain-barrier permeability continues to be a limitation of current KP inhibitors.

6.
Sci Rep ; 8(1): 8008, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29789640

RESUMO

The kynurenine pathway (KP) is dysregulated in neuroinflammatory diseases including Alzheimer's disease (AD), however has not been investigated in preclinical AD characterized by high neocortical amyloid-ß load (NAL), prior to cognitive impairment. Serum KP metabolites were measured in the cognitively normal KARVIAH cohort. Participants, aged 65-90 y, were categorised into NAL+ (n = 35) and NAL- (n = 65) using a standard uptake value ratio cut-off = 1.35. Employing linear models adjusting for age and APOEε4, higher kynurenine and anthranilic acid (AA) in NAL+ versus NAL- participants were observed in females (kynurenine, p = 0.004; AA, p = 0.001) but not males (NALxGender, p = 0.001, 0.038, respectively). To evaluate the predictive potential of kynurenine or/and AA for NAL+ in females, logistic regressions with NAL+/- as outcome were carried out. After age and APOEε4 adjustment, kynurenine and AA were individually and jointly significant predictors (p = 0.007, 0.005, 0.0004, respectively). Areas under the receiver operating characteristic curves were 0.794 using age and APOEε4 as predictors, and 0.844, 0.866 and 0.871 when kynurenine, AA and both were added. Findings from the current study exhibit increased KP activation in NAL+ females and highlight the predictive potential of KP metabolites, AA and kynurenine, for NAL+. Additionally, the current study also provides insight into he influence of gender in AD pathogenesis.


Assuntos
Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides/metabolismo , Biomarcadores/sangue , Cinurenina/metabolismo , Neocórtex/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doenças Assintomáticas , Biomarcadores/análise , Biomarcadores/metabolismo , Estudos de Casos e Controles , Estudos de Coortes , Progressão da Doença , Diagnóstico Precoce , Feminino , Humanos , Cinurenina/sangue , Masculino , Redes e Vias Metabólicas , Neocórtex/patologia , Projetos Piloto , Valor Preditivo dos Testes , Agregados Proteicos
7.
ACS Chem Neurosci ; 9(7): 1616-1624, 2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-29708326

RESUMO

Ethanol is a principle ingredient of alcoholic beverages with potential neurotoxicity and genotoxicity, and the ethanol-associated oxidative DNA damage in the central nervous system is well documented. Natural source compounds may offer new options to protect the brain against ethanol-induced genotoxicity. Veratrum maackii Regel is a toxic rangeland plant linked to teratogenicity which is also used in traditional Chinese medicine as "Lilu" and is reported to contain a family of compounds called stilbenes that can have positive biological activity. In this study, nine stilbenes were isolated from the aerial parts of V. maackii Regel, and their structures were identified as cis-mulberroside A (1), resveratrol-4,3'- O-ß-d-diglucopyranoside (2), mulberroside A (3), gentifolin K (4), resveratrol-3,5- O-ß-d-diglucopyranoside (5), oxyresveratrol- 4'- O-ß-d-glucopyranoside (6), oxyresveratrol-3- O-ß-d-glucopyranoside (7), oxyresveratrol (8), and resveratrol (9) using ESI-MS and NMR techniques. The total concentration of extracted compounds 2-9 was 2.04 mg/g, suggesting that V. maackii Regel is a novel viable source of these compounds. In an in vivo comet assay, compounds 1-9 were observed to decrease DNA damage in mouse cerebellum and cerebral cortex caused by acute ethanol administration. Histological observation also revealed decreased brain injury in mice administered with compounds 1-9 after acute ethanol administration. The protective effects of compound 6 were associated with increasing T-SOD and GSH-PX activities and a decrease in NO and MDA concentrations. These findings suggest that these compounds are potent inhibitors of ethanol-induced brain injury possibly via the inhibition of oxidative stress and may be valuable leads for future therapeutic development.


Assuntos
Depressores do Sistema Nervoso Central/efeitos adversos , Dano ao DNA/efeitos dos fármacos , Etanol/efeitos adversos , Substâncias Protetoras/farmacologia , Estilbenos/farmacologia , Veratrum , Transtornos Relacionados ao Uso de Álcool/tratamento farmacológico , Transtornos Relacionados ao Uso de Álcool/metabolismo , Transtornos Relacionados ao Uso de Álcool/patologia , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Cerebelo/patologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Masculino , Camundongos , Estrutura Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fototerapia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Substâncias Protetoras/química , Substâncias Protetoras/isolamento & purificação , Distribuição Aleatória , Estilbenos/química , Estilbenos/isolamento & purificação
8.
Chem Commun (Camb) ; 54(29): 3609-3612, 2018 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-29570195

RESUMO

A superior biocompatible spherical nucleic acid (SNA) conjugate was fabricated by grafting siRNA onto the surface of a core composed of a spherical DNA nanostructure that we have termed a DNA nanoclew (DC). After uptake by cultured cancer cells, SNA nanoparticles release engrafted siRNAs by cleavage of the intracellular Dicer enzyme. Moreover, in vitro experiments reveal that such SNAs demonstrate potent gene knockdown at both mRNA and protein levels, while with negligible cytotoxicity.


Assuntos
DNA/química , Sistemas de Liberação de Medicamentos/métodos , Técnicas de Silenciamento de Genes/métodos , Nanopartículas/química , RNA Interferente Pequeno/administração & dosagem , Inativação Gênica , Células HeLa , Humanos , Nanopartículas/toxicidade , Hibridização de Ácido Nucleico , Tamanho da Partícula , RNA Interferente Pequeno/química , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/toxicidade , Ribonuclease III/química
9.
Curr Med Chem ; 24(23): 2471-2495, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28464785

RESUMO

Disrupted kynurenine pathway (KP) metabolism has been implicated in the progression of neurodegenerative disease, psychiatric disorders and cancer. Modulation of enzyme activity along this pathway may therefore offer potential new therapeutic strategies for these conditions. Considering their prominent positions in the KP, the enzymes indoleamine 2,3-dioxygenase, kynurenine 3-monooxygenase and kynurenine aminotransferase, appear the most attractive targets. Already, increasing interest in this pathway has led to the identification of a number of potent and selective enzyme inhibitors with promising pre-clinical data and the elucidation of several enzyme crystal structures provides scope to rationalize the molecular mechanisms of inhibitor activity. The field seems poised to yield one or more inhibitors that should find clinical utility.


Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Indolamina-Pirrol 2,3,-Dioxigenase/antagonistas & inibidores , Quinurenina 3-Mono-Oxigenase/antagonistas & inibidores , Cinurenina/metabolismo , Transaminases/antagonistas & inibidores , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Quinurenina 3-Mono-Oxigenase/metabolismo , Transaminases/metabolismo
10.
Sci Rep ; 7: 41473, 2017 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-28155867

RESUMO

Activation of the kynurenine pathway (KP) of tryptophan metabolism results from chronic inflammation and is known to exacerbate progression of neurodegenerative disease. To gain insights into the links between inflammation, the KP and multiple sclerosis (MS) pathogenesis, we investigated the KP metabolomics profile of MS patients. Most significantly, we found aberrant levels of two key KP metabolites, kynurenic acid (KA) and quinolinic acid (QA). The balance between these metabolites is important as it determines overall excitotoxic activity at the N-methyl-D-Aspartate (NMDA) receptor. We also identified that serum KP metabolic signatures in patients can discriminate clinical MS subtypes with high sensitivity and specificity. A C5.0 Decision Tree classification model discriminated the clinical subtypes of MS with a sensitivity of 91%. After validation in another independent cohort, sensitivity was maintained at 85%. Collectively, our studies suggest that abnormalities in the KP may be associated with the switch from early-mild stage MS to debilitating progressive forms of MS and that analysis of KP metabolites in MS patient serum may have application as MS disease biomarkers.


Assuntos
Progressão da Doença , Cinurenina/metabolismo , Redes e Vias Metabólicas , Metabolômica , Esclerose Múltipla/metabolismo , Adulto , Biomarcadores/metabolismo , Estudos de Coortes , Simulação por Computador , Demografia , Feminino , Seguimentos , Humanos , Imunidade Inata , Masculino , Metaboloma , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Esclerose Múltipla/líquido cefalorraquidiano , Esclerose Múltipla/imunologia , Índice de Gravidade de Doença
11.
Autism Res ; 9(6): 621-31, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26497015

RESUMO

Dysfunction of the serotoninergic and glutamatergic systems is implicated in the pathogenesis of autism spectrum disorder (ASD) together with various neuroinflammatory mediators. As the kynurenine pathway (KP) of tryptophan degradation is activated in neuroinflammatory states, we hypothesized that there may be a link between inflammation in ASD and enhanced KP activation resulting in reduced serotonin synthesis from tryptophan and production of KP metabolites capable of modulating glutamatergic activity. A cross-sectional study of 15 different Omani families with newly diagnosed children with ASD (n = 15) and their age-matched healthy siblings (n = 12) was designed. Immunological profile and the KP metabolic signature were characterized in the study participants. Our data indicated that there were alterations to the KP in ASD. Specifically, increased production of the downstream metabolite, quinolinic acid, which is capable of enhancing glutamatergic neurotransmission was noted. Correlation studies also demonstrated that the presence of inflammation induced KP activation in ASD. Until now, previous studies have failed to establish a link between inflammation, glutamatergic activity, and the KP. Our findings also suggest that increased quinolinic acid may be linked to 16p11.2 mutations leading to abnormal glutamatergic activity associated with ASD pathogenesis and may help rationalize the efficacy of sulforaphane treatment in ASD. Autism Res 2016, 9: 621-631. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.


Assuntos
Transtorno Autístico/imunologia , Transtorno Autístico/metabolismo , Ácido Glutâmico/imunologia , Ácido Glutâmico/metabolismo , Cinurenina/imunologia , Cinurenina/metabolismo , Adolescente , Animais , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Masculino , Omã , Irmãos
12.
Oncotarget ; 7(6): 6506-20, 2016 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-26646699

RESUMO

Breast cancer (BrCa) is the leading cause of cancer related death in women. While current diagnostic modalities provide opportunities for early medical intervention, significant proportions of breast tumours escape treatment and metastasize. Gaining increasing recognition as a factor in tumour metastasis is the local immuno-surveillance environment. Following identification of the role played by the enzyme indoleamine dioxygenase 1 (IDO1) in mediating maternal foetal tolerance, the kynurenine pathway (KP) of tryptophan metabolism has emerged as a key metabolic pathway contributing to immune escape. In inflammatory conditions activation of the KP leads to the production of several immune-modulating metabolites including kynurenine, kynurenic acid, 3-hydroxykynurenine, anthranilic acid, 3-hydroxyanthranilic acid, picolinic acid and quinolinic acid. KP over-activation was first described in BrCa patients in the early 1960s. More evidence has since emerged to suggest that the IDO1 is elevated in advanced BrCa patients and is associated with poor prognosis. Further, IDO1 positive breast tumours have a positive correlation with the density of immune suppressive Foxp3+ T regulatory cells and lymph node metastasis. The analysis of clinical microarray data in invasive BrCa compared to normal tissue showed, using two microarray databank (cBioportal and TCGA), that 86.3% and 91.4% BrCa patients have altered KP enzyme expression respectively. Collectively, these data highlight the key roles played by KP activation in BrCa, particularly in basal BrCa subtypes where expression of most KP enzymes was altered. Accordingly, the use of KP enzyme inhibitors in addition to standard chemotherapy regimens may present a viable therapeutic approach.


Assuntos
Neoplasias da Mama/imunologia , Neoplasias da Mama/terapia , Imunidade Celular/imunologia , Cinurenina/metabolismo , Transdução de Sinais , Animais , Neoplasias da Mama/metabolismo , Feminino , Humanos
13.
Front Aging Neurosci ; 6: 173, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25100994

RESUMO

Modulations of the potentially toxic transition metals iron (Fe) and copper (Cu) are implicated in the neurodegenerative process in a variety of human disease states including amyotrophic lateral sclerosis (ALS). However, the precise role played by these metals is still very much unclear, despite considerable clinical and experimental data suggestive of a role for these elements in the neurodegenerative process. The discovery of mutations in the antioxidant enzyme Cu/Zn superoxide dismutase 1 (SOD-1) in ALS patients established the first known cause of ALS. Recent data suggest that various mutations in SOD-1 affect metal-binding of Cu and Zn, in turn promoting toxic protein aggregation. Copper homeostasis is also disturbed in ALS, and may be relevant to ALS pathogenesis. Another set of interesting observations in ALS patients involves the key nutrient Fe. In ALS patients, Fe loading can be inferred by studies showing increased expression of serum ferritin, an Fe-storage protein, with high serum ferritin levels correlating to poor prognosis. Magnetic resonance imaging of ALS patients shows a characteristic T2 shortening that is attributed to the presence of Fe in the motor cortex. In mutant SOD-1 mouse models, increased Fe is also detected in the spinal cord and treatment with Fe-chelating drugs lowers spinal cord Fe, preserves motor neurons, and extends lifespan. Inflammation may play a key causative role in Fe accumulation, but this is not yet conclusive. Excess transition metals may enhance induction of endoplasmic reticulum (ER) stress, a system that is already under strain in ALS. Taken together, the evidence suggests a role for transition metals in ALS progression and the potential use of metal-chelating drugs as a component of future ALS therapy.

14.
J Inorg Biochem ; 129: 43-51, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24028863

RESUMO

Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-resistant (7G8) strains of P. falciparum in culture compared to desferrioxamine (DFO). The present study examined the effects of 311, N4mT and N4pT on erythrocyte membrane integrity and asexual parasite development. While the characteristic biconcave disk shape of the erythrocytes was unaffected, the chelators caused very slight hemolysis at IC50 values that inhibited parasite growth. The chelators 311, N4mT and N4pT affected all stages of the intra-erythrocytic development cycle (IDC) of P. falciparum in culture. However, while these ligands primarily affected the ring-stage, DFO inhibited primarily trophozoite and schizont-stages. Ring, trophozoite and schizont-stages of the IDC were inhibited by significantly lower concentrations of 311, N4mT, and N4pT (IC50=4.45±1.70, 10.30±4.40, and 3.64±2.00µM, respectively) than DFO (IC50=23.43±3.40µM). Complexation of 311, N4mT and N4pT with iron reduced their anti-plasmodial activity. Estimation of the intracellular labile iron pool (LIP) in erythrocytes showed that the chelation efficacy of 311, N4mT and N4pT corresponded to their anti-plasmodial activities, suggesting that the LIP may be a potential source of non-heme iron for parasite metabolism within the erythrocyte. This study has implications for malaria chemotherapy that specifically disrupts parasite iron utilization.


Assuntos
Antimaláricos , Membrana Eritrocítica/metabolismo , Hidrazonas , Quelantes de Ferro , Plasmodium falciparum/metabolismo , Semicarbazidas , Antimaláricos/química , Antimaláricos/farmacologia , Membrana Eritrocítica/química , Hemólise/efeitos dos fármacos , Humanos , Hidrazonas/química , Hidrazonas/farmacologia , Quelantes de Ferro/química , Quelantes de Ferro/farmacologia , Semicarbazidas/química , Semicarbazidas/farmacologia
15.
Mol Pharmacol ; 83(1): 179-90, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23074173

RESUMO

Deferasirox is an orally effective iron (Fe) chelator currently used for the treatment of iron-overload disease and has been implemented as an alternative to the gold standard chelator, desferrioxamine (DFO). Earlier studies demonstrated that DFO exhibits anticancer activity due to its ability to deplete cancer cells of iron. In this investigation, we examined the in vitro and in vivo activity of deferasirox against cells from human solid tumors. To date, there have been no studies to investigate the effect of deferasirox on these types of tumors in vivo. Deferasirox demonstrated similar activity at inhibiting proliferation of DMS-53 lung carcinoma and SK-N-MC neuroepithelioma cell lines compared with DFO. Furthermore, deferasirox was generally similar or slightly more effective than DFO at mobilizing cellular (59)Fe and inhibiting iron uptake from human transferrin depending on the cell type. However, deferasirox potently inhibited DMS-53 xenograft growth in nude mice when given by oral gavage, with no marked alterations in normal tissue histology. To understand the antitumor activity of deferasirox, we investigated its effect on the expression of molecules that play key roles in metastasis, cell cycle control, and apoptosis. We demonstrated that deferasirox increased expression of the metastasis suppressor protein N-myc downstream-regulated gene 1 and upregulated the cyclin-dependent kinase inhibitor p21(CIP1/WAF1) while decreasing cyclin D1 levels. Moreover, this agent increased the expression of apoptosis markers, including cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase 1. Collectively, we demonstrate that deferasirox is an orally effective antitumor agent against solid tumors.


Assuntos
Antineoplásicos/farmacologia , Benzoatos/farmacologia , Quelantes de Ferro/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Triazóis/farmacologia , Administração Oral , Animais , Antígenos CD/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Benzoatos/uso terapêutico , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Cobre/metabolismo , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Deferasirox , Feminino , Humanos , Ferro/metabolismo , Quelantes de Ferro/uso terapêutico , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Transplante de Neoplasias , Tumores Neuroectodérmicos Primitivos Periféricos , Proteínas Serina-Treonina Quinases/metabolismo , Receptores da Transferrina/metabolismo , Carcinoma de Pequenas Células do Pulmão/patologia , Transplante Heterólogo , Triazóis/uso terapêutico , Zinco/metabolismo
16.
Artigo em Inglês | MEDLINE | ID: mdl-22954966

RESUMO

In the current study, we developed a HPLC method to quantitatively measure the permeability of the BpT-based chelators, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and 2-benzoylpyridine 4-allyl-3-thiosemicarbazone (Bp4aT), across human colorectal adenocarcinoma (Caco-2) monolayers as a model of gut absorption. In aqueous solution, Bp4eT and Bp4aT formed inter-convertible Z and E isomers that were resolved by HPLC. Peak area was linear with respect to chelator concentration. Acceptable within-day and between-day precision (<22%) and accuracy (85-115% of true values) were obtained over a range of 1.0-100µM for Bp4eT and 1.5-300µM for Bp4aT. Limits of detection were 0.3µM and 1µM for Bp4eT and Bp4aT, respectively, while corresponding limits of quantification were 1µM and 5µM. Both chelators showed significant ability to chelate iron in THP-1 cells using a calcein-based assay and no apparent cytotoxicity was observed within 24h. Ratios of the apical to basolateral and basolateral to apical transport for Bp4eT were 1.10 and 0.89 at 100µM and 300µM respectively, indicating equal bi-directional movement of the compounds. Similarly, ratios were 0.77 and 0.92 for Bp4aT, respectively. This study demonstrates that Bp4eT and Bp4aT can be efficiently transported through Caco-2 cells and can potentially be formulated for oral delivery.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Quelantes de Ferro/análise , Quelantes de Ferro/farmacocinética , Tiossemicarbazonas/análise , Tiossemicarbazonas/farmacocinética , Células CACO-2 , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Ferro/metabolismo , Quelantes de Ferro/química , Quelantes de Ferro/farmacologia , Isomerismo , Isoquinolinas/metabolismo , Limite de Detecção , Modelos Biológicos , Reprodutibilidade dos Testes , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia
17.
J Med Chem ; 55(16): 7230-44, 2012 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-22861499

RESUMO

We developed a series of second-generation di-2-pyridyl ketone thiosemicarbazone (DpT) and 2-benzoylpyridine thiosemicarbazone (BpT) ligands to improve the efficacy and safety profile of these potential antitumor agents. Two novel DpT analogues, Dp4e4mT and DpC, exhibited pronounced and selective activity against human lung cancer xenografts in vivo via the intravenous and oral routes. Importantly, these analogues did not induce the cardiotoxicity observed at high nonoptimal doses of the first-generation DpT analogue, Dp44mT. The Cu(II) complexes of these ligands exhibited potent antiproliferative activity having redox potentials in a range accessible to biological reductants. The activity of the copper complexes of Dp4e4mT and DpC against lung cancer cells was synergistic in combination with gemcitabine or cisplatin. It was demonstrated by EPR spectroscopy that dimeric copper compounds of the type [CuLCl](2), identified crystallographically, dissociate in solution to give monomeric 1:1 Cu:ligand complexes. These monomers represent the biologically active form of the complex.


Assuntos
Antineoplásicos/síntese química , Complexos de Coordenação/síntese química , Cobre , Cetonas/síntese química , Neoplasias Pulmonares/tratamento farmacológico , Piridinas/síntese química , Tiossemicarbazonas/síntese química , Administração Oral , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Dimerização , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Humanos , Injeções Intravenosas , Cetonas/química , Cetonas/farmacologia , Camundongos , Camundongos Nus , Transplante de Neoplasias , Oxirredução , Piridinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia , Transferrina/metabolismo , Transplante Heterólogo
18.
Mol Pharmacol ; 82(1): 105-14, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22508546

RESUMO

Thiosemicarbazones are a group of compounds that have received comprehensive investigation as anticancer agents. The antitumor activity of the thiosemicarbazone, 3-amino-2-pyridinecarboxaldehyde thiosemicarbazone (3-AP; triapine), has been extensively assessed in more than 20 phase I and II clinical trials. These studies have demonstrated that 3-AP induces methemoglobin (metHb) formation and hypoxia in patients, limiting its usefulness. Considering this problem, we assessed the mechanism of metHb formation by 3-AP compared with that of more recently developed thiosemicarbazones, including di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT). This was investigated using intact red blood cells (RBCs), RBC lysates, purified oxyhemoglobin, and a mouse model. The chelation of cellular labile iron with the formation of a redox-active thiosemicarbazone-iron complex was found to be crucial for oxyhemoglobin oxidation. This observation was substantiated using a thiosemicarbazone that cannot ligate iron and also by using the chelator, desferrioxamine, that forms a redox-inactive iron complex. Of significance, cellular copper chelation was not important for metHb generation in contrast to its role in preventing tumor cell proliferation. Administration of Dp44mT to mice catalyzed metHb and cardiac metmyoglobin formation. However, ascorbic acid administered together with the drug in vivo significantly decreased metHb levels, providing a potential therapeutic intervention. Moreover, we demonstrated that the structure of the thiosemicarbazone is of importance in terms of metHb generation, because the DpT analog, di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), does not induce metHb generation in vivo. Hence, DpC represents a next-generation thiosemicarbazone that possesses markedly superior properties. This investigation is important for developing more effective thiosemicarbazone treatment regimens.


Assuntos
Antineoplásicos/farmacologia , Metemoglobina/metabolismo , Piridinas/farmacologia , Tiossemicarbazonas/farmacologia , Animais , Ácido Ascórbico , Proliferação de Células/efeitos dos fármacos , Desferroxamina/farmacologia , Interações Medicamentosas , Eritrócitos/efeitos dos fármacos , Humanos , Hipóxia/induzido quimicamente , Ferro/metabolismo , Quelantes de Ferro/farmacologia , Cinética , Camundongos , Oxirredução/efeitos dos fármacos , Oxiemoglobinas/metabolismo
19.
J Med Chem ; 54(19): 6936-48, 2011 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-21846118

RESUMO

Iron chelators of the 2'-benzoylpyridine thiosemicarbazone (BpT) class show substantial potential as anticancer agents. To explore structure-activity relationships, new BpT analogues were designed that incorporated halogen substituents on the noncoordinating phenyl group (XBpTs). These XBpT ligands exhibited potent antiproliferative activity with some analogues exceeding that of the parent BpT compound. Importantly, there was an appreciable therapeutic index in vitro, as mortal cells were significantly less affected by these chelators relative to neoplastic cells. The addition of a halogen led to a halogen-specific increase in the redox potential of XBpT-Fe complexes. Probing for chelator-induced intracellular reactive oxygen species (ROS) with the fluorescent probe, 2',7'-dichlorofluorescein, revealed a 1.5-4.7-fold increase in fluorescence upon incorporation of Cl, Br, or I to the parent analogues. Furthermore, an important structure-activity relationship was deduced where the addition of halogens led to a positive correlation between intracellular ROS generation and antiproliferative activity in the more hydrophilic BpT parent compounds.


Assuntos
Antineoplásicos/síntese química , Complexos de Coordenação/síntese química , Quelantes de Ferro/síntese química , Piridinas/síntese química , Tiossemicarbazonas/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Ácido Ascórbico/química , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Eletroquímica , Fluoresceínas , Corantes Fluorescentes , Fluorometria , Humanos , Interações Hidrofóbicas e Hidrofílicas , Quelantes de Ferro/química , Estrutura Molecular , Oxirredução , Piridinas/química , Piridinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia
20.
Cancer Res ; 71(17): 5871-80, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21750178

RESUMO

The metal-chelating compound Dp44mT is a di-2-pyridylketone thiosemicarbazone (DpT) which displays potent and selective antitumor activity. This compound is receiving translational attention, but its mechanism is poorly understood. Here, we report that Dp44mT targets lysosome integrity through copper binding. Studies using the lysosomotropic fluorochrome acridine orange established that the copper-Dp44mT complex (Cu[Dp44mT]) disrupted lysosomes. This targeting was confirmed with pepstatin A-BODIPY FL, which showed redistribution of cathepsin D to the cytosol with ensuing cleavage of the proapoptotic BH3 protein Bid. Redox activity of Cu[Dp44mT] caused cellular depletion of glutathione, and lysosomal damage was prevented by cotreatment with the glutathione precursor N-acetylcysteine. Copper binding was essential for the potent antitumor activity of Dp44mT, as coincubation with nontoxic copper chelators markedly attenuated its cytotoxicity. Taken together, our studies show how the lysosomal apoptotic pathway can be selectively activated in cancer cells by sequestration of redox-active copper. Our findings define a novel generalized strategy to selectively target lysosome function for chemotherapeutic intervention against cancer.


Assuntos
Antineoplásicos/metabolismo , Quelantes/metabolismo , Cobre/metabolismo , Lisossomos/efeitos dos fármacos , Tiossemicarbazonas/metabolismo , Laranja de Acridina/metabolismo , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quelantes/farmacologia , Humanos , Ferro/metabolismo , Lisossomos/metabolismo , Mitocôndrias/efeitos dos fármacos , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Tiossemicarbazonas/farmacologia
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