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1.
Schizophrenia (Heidelb) ; 9(1): 16, 2023 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-36934103

RESUMO

Patients with schizophrenia (SZ) display moderate reductions in brainstem volumes, including the midbrain, pons, superior cerebellar peduncle, and medulla oblongata. Here, we investigated alterations in brainstem volumes between SZ patients and healthy controls (HCs) stratified by sex. T1-weighted MRI brain scans were processed with FreeSurfer v6.0 in 156 SZ patients (61 males/95 females) and 205 HCs (133/72). Of the brainstem structures, pons volumes were significantly reduced, particularly in male SZ patients. The decreased pons volumes were correlated with lower levels of education but not duration of illness in male patients. These findings suggest that the reduction in pons volume in male patients might be occurred before or around the onset of the disorder.

2.
Intern Med ; 57(5): 757-760, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29093414

RESUMO

A 70-year-old man with malignant lymphoma was subjected to a fourth course of chemotherapy using gemcitabine and cisplatin. During the intravenous infusion of anticancer agents, pain and redness was observed at the site of insertion. The patient was subsequently treated with the strongest topical steroids and topical cooling agents. However, 2 weeks later, the affected area turned yellow, and the histopathological findings revealed skin necrosis of the entire dermis layer. It took two and a half months to cure the lesion. Close attention should be paid to the development of skin necrosis even when irritant anticancer agents such as gemcitabine and cisplatin are administered.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cisplatino/efeitos adversos , Desoxicitidina/análogos & derivados , Reação no Local da Injeção/etiologia , Pele/patologia , Idoso , Cisplatino/administração & dosagem , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Humanos , Infusões Intravenosas , Irritantes/administração & dosagem , Irritantes/efeitos adversos , Linfoma/tratamento farmacológico , Masculino , Necrose/induzido quimicamente , Gencitabina
3.
Biol Pharm Bull ; 39(12): 1932-1938, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27904035

RESUMO

Stroke-prone spontaneously hypertensive rats (SHRSP/Izm; SHRSP) develop severe hypertension and die of cerebral stroke. However, the genetic mechanisms underlying their stroke susceptibility have not been clarified yet. In this study, we used astrocytes from the newborn brain cortex of spontaneously hypertensive rats (SHR/Izm; SHR) and SHRSP to find the difference of genetic characteristics. Astrocytes are known to have functions of vasodilation and nutrient uptake for neurons in the brain. The continuous generation of hydrogen peroxide (H2O2) dose-dependently causes cell death in astrocytes, and SHRSP was more vulnerable than SHR. We found that the total thiols decreased in SHRSP astrocytes but the total glutathione (GSH) did not change. Hydrogen sulfide (H2S), which is known to protect cells through anti-oxidant and vasodilatory effects, is produced by cystathionine ß-synthase (CBS) in astrocytes. We found that H2S production was significantly decreased in SHRSP as compared to SHR. This was caused by the decreasing expression of mRNA, protein and enzyme activity of CBS in astrocytes. We also found that astrocyte cell death from oxidative stress could be prevented by GYY4137 H2S donor. H2S is also known to cause protein S-sulfhydration to modify enzyme activity. Sulfane sulfur in astrocytes was significantly lower in SHRSP and decreased by CBS inhibitor. We showed that astrocytes in SHRSP vulnerable to oxidative stress may be caused by reduction of H2S through lower expression and activity of CBS.


Assuntos
Astrócitos/metabolismo , Cistationina beta-Sintase/metabolismo , Sulfeto de Hidrogênio/metabolismo , Hipertensão/metabolismo , Enxofre/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Encéfalo/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cistationina beta-Sintase/genética , Glucose Oxidase/farmacologia , Glutationa/metabolismo , Dissulfeto de Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Morfolinas/farmacologia , Compostos Organotiofosforados/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Ratos Endogâmicos SHR , Acidente Vascular Cerebral/metabolismo
4.
J Epidemiol ; 24(3): 200-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24705646

RESUMO

BACKGROUND: We investigated the prevalence of hallux valgus (HV) and examined its association with various factors in a cross-sectional study of Japanese female university students. METHODS: A questionnaire survey of foot symptoms, lifestyle, and body mass index (BMI) was administered to 343 women who provided informed consent at a women's university. Footprints were obtained and bone density was measured. Associations of HV with various factors were analyzed by logistic regression analysis. RESULTS: Big toe pain was reported in 26.5% of the women. HV (HV angle, ≥15°) was present in the left foot in 22.4%, the right foot in 20.7%, and unilaterally or bilaterally in 29.7% of women. Mild HV (HV angle, ≥15° to <20°) was noted in the left foot and right foot in 13.4% and 13.1% of women, respectively; no severe HV (HV angle, ≥40°) was observed. HV was associated with big toe pain (adjusted OR: 3.56, 95% CI: 2.01-6.32), history of HV in the mother or maternal grandmother (adjusted OR: 2.45, 95% CI: 1.19-5.02), and history of HV in other family members (adjusted OR: 3.09, 95% CI: 1.35-7.06). Moderate HV was associated with big toe pain (adjusted OR: 4.58, 95% CI: 2.17-9.66) and history of HV in the mother or maternal grandmother (adjusted OR: 3.36, 95% CI: 1.40-8.07). The proportion of women with big toe pain increased significantly with HV severity. CONCLUSIONS: HV was present in about 30% of female university students. Young women with big toe pain or a family history of HV should be evaluated for HV.


Assuntos
Hallux Valgus/epidemiologia , Estudantes/estatística & dados numéricos , Estudos Transversais , Feminino , Hallux Valgus/genética , Humanos , Japão/epidemiologia , Dor , Prevalência , Fatores de Risco , Inquéritos e Questionários , Dedos do Pé/patologia , Universidades , Adulto Jovem
5.
Eur J Dermatol ; 23(3): 362-5, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23797684

RESUMO

IgA pemphigus is a rare variant of pemphigus. IgA pemphigus is subdivided into intraepidermal neutrophilic IgA dermatosis-type (IEN-type), whose target antigen is still an enigma, and subcorneal pustular dermatosis-type, whose target antigen is desmocollin 1 (Dsc1). We report a 56-year-old Japanese male with IgA pemphigus showing atypical erythema. One month after erythema developed, the patient visited his private physician, and was tentatively diagnosed as having erythema multiforme. The patient had been intermittently treated with a low dose of oral prednisolone for a year without benefit before visiting our hospital. Clinical examination revealed irregularly-shaped and partially edematous erythema over the trunk and extremities without mucosal involvement. Neither bullae nor pustules were seen during the course. Direct immunofluorescence showed IgA deposition on cell surfaces of keratinocytes in the upper two thirds of the epidermis. Indirect immunofluorescence of monkey esophagus sections revealed IgA and IgG anti-cell surface antibodies. Our new enzyme-linked immunosorbent assays using eukaryotic recombinant proteins of human Dsc 1-3 detected IgA antibodies to Dsc1 and Dsc2. Although no apparent bullae were observed, the diagnosis of IgA pemphigus was made. Prednisolone 30 mg daily was required to control erythematous lesions. Although the pathomechanism for the unique skin lesion is unknown, the possibility that IgA pemphigus has a prodromal phase and that early administration of low dose prednisolone suppressed the development of pustules or bullae were considered.


Assuntos
Desmocolinas/imunologia , Eritema/imunologia , Imunoglobulina A , Pênfigo/imunologia , Pênfigo/patologia , Eritema/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Pênfigo/complicações
6.
Life Sci ; 92(13): 808-14, 2013 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-23454167

RESUMO

AIM: Cell death induced by excessive activation of poly(ADP-ribose) polymerase (PARP) is inhibited by administration of NAD(+) extracellularly, but its preventive mechanism remains unclear. Here we investigated the involvement of NAD(+) and/or its metabolites, adenosine and nicotinamide, in the rescue of PARP-mediated astrocyte death by NAD(+) and explored the pathway through which intact NAD(+) could enter cells. MAIN METHODS: PARP activation was induced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine, a DNA-alkylating agent. The cellular NAD(+) content was determined by an enzymatic recycling assay, and cell viability was determined by measuring intracellular LDH activity. KEY FINDINGS: NAD(+), but not adenosine and nicotinamide, could restore the cellular NAD(+) levels decreased by PARP activation. Pharmacological inhibition of the uptake of adenosine and nicotinamide had no effect on the prevention of PARP-triggered cell death by NAD(+), suggesting that unmetabolized NAD(+) remaining in the extracellular milieu might prevent PARP-mediated NAD(+) consumption and cell death. The increase in the cellular NAD(+) level caused by NAD(+) administration to PARP-activated cells was significantly inhibited by a connexin hemichannel blocker, carbenoxolone, but not by P2X7 receptor inhibition with selective antagonists and siRNA, or pannexin-selective blockers. Finally, pharmacological blockade of connexin hemichannels with 18ß-glycyrrhetinic acid, octanol and carbenoxolone inhibited the NAD(+)-mediated cell rescue of PARP-triggered cell death. SIGNIFICANCE: These findings suggested that intact NAD(+) could get into astrocytes through connexin hemichannels, and that this process should play a key role in NAD(+)-mediated prevention of PARP-triggered astrocyte death.


Assuntos
Astrócitos/citologia , Conexinas/metabolismo , NAD/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Adenosina/metabolismo , Animais , Astrócitos/metabolismo , Transporte Biológico/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Conexinas/antagonistas & inibidores , Metilnitronitrosoguanidina/metabolismo , Camundongos , Niacinamida/metabolismo , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X7/metabolismo
7.
J Neurochem ; 122(6): 1118-28, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22774935

RESUMO

P2X7 receptor (P2X7R) is known to be a 'death receptor' in immune cells, but its functional expression in non-immune cells such as neurons is controversial. Here, we examined the involvement of P2X7R activation and mitochondrial dysfunction in ATP-induced neuronal death in cultured cortical neurons. In P2X7R- and pannexin-1-expressing neuron cultures, 5 or more mM ATP or 0.1 or more mM BzATP induced neuronal death including apoptosis, and cell death was prevented by oxATP, P2X7R-selective antagonists. ATP-treated neurons exhibited Ca(2+) entry and YO-PRO-1 uptake, the former being inhibited by oxATP and A438079, and the latter by oxATP and carbenoxolone, while P2X7R antagonism with oxATP, but not pannexin-1 blocking with carbenoxolone, prevented the ATP-induced neuronal death. The ATP treatment induced reactive oxygen species generation through activation of NADPH oxidase and activated poly(ADP-ribose) polymerase, but both of them made no or negligible contribution to the neuronal death. Rhodamine123 efflux from neuronal mitochondria was increased by the ATP-treatment and was inhibited by oxATP, and a mitochondrial permeability transition pore inhibitor, cyclosporine A, significantly decreased the ATP-induced neuronal death. In ATP-treated neurons, the cleavage of pro-caspase-3 was increased, and caspase inhibitors, Q-VD-OPh and Z-DEVD-FMK, inhibited the neuronal death. The cleavage of apoptosis-inducing factor was increased, and calpain inhibitors, MDL28170 and PD151746, inhibited the neuronal death. These findings suggested that P2X7R was functionally expressed by cortical neuron cultures, and its activation-triggered Ca(2+) entry and mitochondrial dysfunction played important roles in the ATP-induced neuronal death.


Assuntos
Mitocôndrias/metabolismo , Mitocôndrias/patologia , Neurônios/metabolismo , Neurônios/patologia , Receptores Purinérgicos P2X7/metabolismo , Trifosfato de Adenosina/toxicidade , Animais , Sinalização do Cálcio/fisiologia , Morte Celular/fisiologia , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Doenças Mitocondriais/fisiopatologia , Cultura Primária de Células , Ratos , Receptores Purinérgicos P2X7/fisiologia
8.
Neurosci Lett ; 498(1): 52-6, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21575674

RESUMO

In the oxidative stress-loaded brain, extracellular adenosine levels are elevated and thereby neuronal damage is attenuated, but mechanisms underlying alteration of the extracellular kinetics of adenosine remain unclear. Here we investigated whether oxidative stress might alter functional expression of nucleoside transporters (NTs), a predominant regulatory system for nucleoside kinetics, in cultured rat astrocytes. Treatment of astrocytes with 0.5mM SIN-1 for 3h caused apparent cellular accumulation of nitrotyrosine, but had no effect on their viability, indicating load of oxidative stress to astrocytes without any change in their viability. Under the condition, [(3)H]adenosine uptake was significantly less than that by control cells. This decreased uptake was due to decrease in adenosine uptake mediated by an equilibrative NT (ENT) 1 which was inhibited by low concentrations (≤0.1 µM) of nitrobenzylthioinosine (NBMPR), but not by sodium-dependent or high concentrations (≥1 µM) of NBMPR-inhibitable nucleoside transporters. The expression level of ENT1 was not altered, while the Michaelis constant, but not the maximum rate, of adenosine uptake was increased. These findings suggest that under oxidative stress-loaded conditions, decreased adenosine clearance via astrocytic ENT1 might involve, at least in part, in an elevated extracellular adenosine level in the brain.


Assuntos
Adenosina/metabolismo , Astrócitos/metabolismo , Proteínas de Transporte de Nucleosídeos/metabolismo , Estresse Oxidativo/fisiologia , Animais , Astrócitos/efeitos dos fármacos , Western Blotting , Imuno-Histoquímica , Molsidomina/análogos & derivados , Molsidomina/farmacologia , Doadores de Óxido Nítrico/farmacologia , Proteínas de Transporte de Nucleosídeos/efeitos dos fármacos , Oxidantes/metabolismo , Oxidantes/farmacologia , Ácido Peroxinitroso/metabolismo , Ácido Peroxinitroso/farmacologia , Ratos , Ratos Wistar
9.
Biol Pharm Bull ; 34(4): 490-4, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21467634

RESUMO

We previously reported that caffeic acid phenethyl ester (CAPE) suppresses 3T3-L1 differentiation to adipocytes through the inhibition of peroxisome proliferator-activated receptor (PPAR) gamma, CCAAT/enhancer-binding protein (C/EBP) alpha, fatty acid synthase (Fas) and adipocytes-specific fatty acid binding protein 2 (aP2) expressions (Juman et al., Biol. Pharm. Bull., 33, 1484-1488 (2010)). In the present study, we confirmed that CAPE had inhibitory effects on increased glycerol-3-phosphate dehydrogenase (GPDH) activity and an increased insulin receptor substrate 1 (IRS-1). Our data show that treatment with 50 µM CAPE significantly reduced the levels of leptin (p<0.05), resistin (p<0.05) and tumor necrosis factor (TNF)-alpha (p<0.05) which are known to aid adipocytokines production in adipocytes. In 3T3-L1 cells, treatment of CAPE decreased the triglyceride deposition similar to resveratrol, which is known to have an inhibitory effect on 3T3-L1 differentiation to adipocytes. In conclusion, we found that CAPE suppresses the production and secretion of adipocytokines from mature adipocytes in 3T3-L1 cells.


Assuntos
Adipócitos/efeitos dos fármacos , Adipocinas/biossíntese , Ácidos Cafeicos/farmacologia , Leptina/biossíntese , Álcool Feniletílico/análogos & derivados , Própole/química , Resistina/biossíntese , Fator de Necrose Tumoral alfa/biossíntese , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Glicerolfosfato Desidrogenase/antagonistas & inibidores , Proteínas Substratos do Receptor de Insulina/antagonistas & inibidores , Camundongos , Álcool Feniletílico/farmacologia , Resveratrol , Estilbenos/farmacologia , Triglicerídeos/biossíntese
10.
Biol Pharm Bull ; 33(9): 1484-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20823561

RESUMO

We investigated the inhibitory effect of caffeic acid phenethyl ester (CAPE) on the differentiation of 3T3-L1 mouse fibroblasts to adipocytes. 3T3-L1 cells were differentiated for adipocytes given high glucose Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1 microM dexamethasone (DEX), 500 microM isobutylmethylxanthine (IBMX), and 5 microg/ml insulin for 7 days. After differentiation, cells were stained with Oil-Red-O to detect oil droplets in adipocytes. Additionally, the cells were lysed and measured for triglyceride contents. Total RNA was isolated from differentiated cells on day 0, 4 and 7. Then, RNA was analyzed using reverse transcription (RT)-polymerase chain reaction (PCR). CAPE dose-dependently suppressed oil droplet accumulation and reduced the droplet size. These findings showed that CAPE at concentrations of 25 to 50 microM could significantly inhibit triglyceride deposition (p<0.05). Treatment of 3T3-L1 with CAPE reduced the mRNA levels of peroxisome proliferator-activated receptor (PPAR) gamma and CCAAT/enhancer-binding protein (C/EBPalpha). Fatty acid synthase (Fas) and adipocyte-specific fatty acid binding protein (aP2) are known to be associated with lipid metabolism in adipocytes, and both Fas mRNA and aP2 mRNA were significantly suppressed by CAPE treatment. These findings suggested that CAPE suppresses 3T3-L1 differentiation to adipocytes through inhibition of PPARgamma, C/EBPalpha, Fas and aP2 expression.


Assuntos
Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Ácidos Cafeicos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Álcool Feniletílico/análogos & derivados , Células 3T3-L1 , Adipócitos/fisiologia , Animais , Diferenciação Celular/fisiologia , Relação Dose-Resposta a Droga , Camundongos , Álcool Feniletílico/farmacologia
11.
Glia ; 58(14): 1757-65, 2010 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-20645413

RESUMO

Nucleotides and nucleosides play important roles by maintaining brain homeostasis, and their extracellular concentrations are mainly regulated by ectonucleotidases and nucleoside transporters expressed by astrocytes. Extracellularly applied NAD(+) prevents astrocyte death caused by excessive activation of poly(ADP-ribose) polymerase-1, of which the molecular mechanism has not been fully elucidated. Recently, exogenous NAD(+) was reported to enter astrocytes via the P2X7 receptor (P2X7R)-associated channel/pore. In this study, we examined whether the intact form of NAD(+) is incorporated into astrocytes. A large portion of extracellularly added NAD(+) was degraded into metabolites such as AMP and adenosine in the extracellular space. The uptake of adenine ring-labeled [(14)C]NAD(+), but not nicotinamide moiety-labeled [(3)H]NAD(+), showed time- and temperature-dependency, and was significantly enhanced on addition of apyrase, and was reduced by 8-Br-cADPR and ARL67156, inhibitors of CD38 and ectoapyrase, respectively, and P2X7R knockdown, suggesting that the detected uptake of [(14)C]NAD(+) resulted from [(14)C]adenosine acting as a metabolite of [(14)C]NAD(+). Pharmacological and genetic inhibition of P2X7R with brilliant blue G, KN-62, oxATP, and siRNA transfection resulted in a decrease of [(3)H]adenosine uptake, and the uptake was also reduced by low concentration of carbenoxolone and pannexin1 selective peptide blocker (10)panx. Taken together, these results indicate that exogenous NAD(+) is degraded by ectonucleotidases and that adenosine, as its metabolite, is taken up into astrocytes via the P2X7R-associated channel/pore.


Assuntos
Adenosina/metabolismo , Astrócitos/metabolismo , Receptores Purinérgicos P2X7/fisiologia , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Células Cultivadas , Conexinas/antagonistas & inibidores , Conexinas/metabolismo , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Inibidores Enzimáticos/farmacologia , Espaço Extracelular/efeitos dos fármacos , Espaço Extracelular/metabolismo , Camundongos , NAD/metabolismo , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Proteínas de Transporte de Nucleosídeos/efeitos dos fármacos , Proteínas de Transporte de Nucleosídeos/metabolismo , Pirofosfatases/metabolismo , Interferência de RNA/fisiologia , Receptores Purinérgicos P2X7/genética
12.
Life Sci ; 86(17-18): 676-82, 2010 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-20188745

RESUMO

AIM: Poly(ADP-ribose) polymerase-1 (PARP-1) is a DNA repair enzyme, and its excessive activation, following ischemia, trauma, etc., depletes cellular nicotinamide adenine dinucleotide (NAD(+)) as a substrate and eventually leads to brain cell death. Nicotinamide, an NAD(+) precursor and a PARP-1 inhibitor, is known to prevent PARP-1-triggered cell death, but there is no available information on the mechanisms involved in its transport. Here we clarified the transport characteristics of nicotinamide in primary cultured mouse astrocytes. MAIN METHODS: Uptake characteristics of [(14)C]nicotinamide were assessed by a conventional method with primary cultured mouse astrocytes. Cell viability and PARP-1 activity were determined with intracellular LDH activity and immunocytochemical detection of PAR accumulation, respectively. KEY FINDINGS: PARP-1 activation was induced by treatment of astrocytes with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), an alkylating agent. MNNG-triggered astrocyte death and PAR accumulation were completely inhibited by treatment with nicotinamide as with DPQ (3,4-dihydro-5-(4-(1-piperidinyl)butoxy)-1(2H)-isoquinolinone), a second generation PARP inhibitor. The uptake of [(14)C]nicotinamide was time-, temperature-, concentration- and pH-dependent, and was inhibited and stimulated by co- and pre-treatment with N-methylnicotinamide, a representative substrate of an organic cation transport system, respectively. Co-treatment of astrocytes with nicotinamide and N-methylnicotinamide resulted in a decrease in PAR accumulation and absolute prevention of cell death. SIGNIFICANCE: These findings suggest that nicotinamide has a protective effect against PARP-1-induced astrocyte death and that its transporter-mediated uptake, which is extracellular pH-sensitive and common to N-methylnicotinamide, is critical for prevention of PARP-1-triggered cell death.


Assuntos
Astrócitos/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Niacinamida/farmacologia , Poli(ADP-Ribose) Polimerases/metabolismo , Complexo Vitamínico B/farmacologia , Animais , Astrócitos/metabolismo , Transporte Biológico , Sobrevivência Celular/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Camundongos , Niacinamida/análogos & derivados , Niacinamida/farmacocinética , Poli(ADP-Ribose) Polimerase-1 , Temperatura , Fatores de Tempo , Complexo Vitamínico B/farmacocinética
13.
Int J Pharm ; 388(1-2): 168-74, 2010 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-20060452

RESUMO

Concentrative nucleoside transporter 1 (CNT1, SLC28A1) is a key molecule for determining the pharmacokinetic/pharmacodynamic profile of a candidate compound derived from a pyrimidine nucleoside, but there is no available information on the differences in the functional profile of this ortholog between man and mouse. Here, using a clone of mouse CNT1 (mCNT1), we investigated its transport characteristics and substrate specificity for synthetic nucleoside analogues, and compared them with those of human CNT1 (hCNT1). In mCNT1-transfected Cos-7 cells, pyrimidine, but not purine, nucleosides showed sodium- and concentration-dependent uptake, and uridine uptake was competitively inhibited by uridine analogues, the rank order of the inhibitory effects being 5-bromouridine>3'-deoxyuridine>2'-deoxyuridine. cis- and trans-Inhibition studies involving synthetic nucleoside drugs revealed that gemcitabine and zidovudine greatly inhibited [(3)H]uridine uptake mediated by mCNT1 in the both cases, while cytarabine and zalcitabine showed small cis-inhibitory effect, and no trans-inhibitory effect on the uptake. These results demonstrate that the transport characteristics of mCNT1 are almost the same as those of hCNT1, suggesting that mice may be a good animal model in evaluation of pyrimidine nucleoside analogues as to their applicability in human therapy.


Assuntos
Proteínas de Membrana Transportadoras/metabolismo , Nucleosídeos/farmacocinética , Animais , Transporte Biológico , Células COS , Chlorocebus aethiops , Humanos , Masculino , Camundongos , Modelos Animais , Nucleosídeos/administração & dosagem , Nucleosídeos/química , Sódio/metabolismo , Especificidade da Espécie , Estereoisomerismo , Especificidade por Substrato
14.
Int J Pharm ; 333(1-2): 56-61, 2007 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-17088032

RESUMO

Various antimetabolites of nucleobase analogues, such as 6-mercaptopurine (6-MP), 6-thioguanine (6-TG) and 5-fluorouracil (5-FU), are used for cancer treatments. The first step in nucleobase analogue drug therapy is entry of these compounds into tumor cells. Equilibrative nucleoside transporter 2 (ENT2) was previously reported to have the dual ability of transporting both nucleosides and nucleobases. In the present study, we investigated whether or not these nucleobase analogues are transported via ENT2, using mouse ENT2-overexpressing Cos-7 cells. The hypoxanthine uptake mediated by ENT2 was significantly reduced by the addition of 6-MP and 6-TG, and the inhibition of the hypoxanthine uptake by the 6-thiopurines was competitive. Transfection of ENT2 cDNA into Cos-7 cells resulted in an increase in 6-MP uptake. The 6-MP uptake via ENT2 showed clear time- and substrate concentration-dependent profiles, and was inhibited by 6-TG in an inhibitor concentration-dependent fashion. On the other hand, uracil was not a substrate for ENT2, and 5-FU had no effect on the hypoxanthine uptake via ENT2. Therefore, we concluded that 6-MP and 6-TG, but not 5-FU, are transported mediated by the same recognition site on ENT2 with hypoxanthine.


Assuntos
Antimetabólitos Antineoplásicos/metabolismo , Permeabilidade da Membrana Celular , Transportador Equilibrativo 2 de Nucleosídeo/metabolismo , Mercaptopurina/metabolismo , Tioguanina/metabolismo , Animais , Ligação Competitiva , Células COS , Chlorocebus aethiops , Transportador Equilibrativo 2 de Nucleosídeo/genética , Fluoruracila/metabolismo , Guanina/metabolismo , Hipoxantina/metabolismo , Cinética , Camundongos , Transfecção , Uracila/metabolismo , Uridina/metabolismo
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