Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.442
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-32559029

RESUMO

This in vivo study assessed the effect of mineral trioxide aggregate (MTA) as a matrix carrier for recombinant human platelet-derived growth factor (rhPDGF) and enamel matrix protein (EMP) on pulp tissue healing following pulp capping. Eighteen intact human premolars scheduled for extraction were included. Coronal access and pulpotomy were performed, and each tooth was left exposed to the oral cavity for 1 hour before pulp capping was performed. Teeth were randomly assigned to one of the following pulp-capping groups (n = 6 each): Group 1 (MTA only); Group 2 (MTA+EMP); or Group 3 (MTA+rhPDGF). Coronal access cavities were then sealed. Immediate preoperative, postoperative, and 4-month follow-up radiographs were taken. At 4 months, the teeth were extracted atraumatically, and histomorphometric and micro-computed tomography (µCT) analyses were performed. Group 1 showed a thin, uneven, irregular dentin-like structure. Its average thickness was 0.3 ± 0.084 mm measured histologically and 0.29 ± 0.091 mm measured by µCT. Group 2 showed of a nonporous, even-thickness dentin-like structure with multiple root-canal obliterations. Highly dense, atubular dentin-like structures associated with presence of odontoblastic lacunae were seen. The structure's average thickness was 0.87 ± 0.09 mm (histologically) and 0.81 ± 0.17 mm (µCT). Group 3 showed a thick and complete 3D continuous seal of newly formed dentin-like structure covering the pulpal space. It resembled secondary dentin in form, porosity, and tubular structural organization, and its average thickness was 0.94 ± 0.02 mm (histologically) and 0.91 ± 0.09 mm (µCT). Groups 2 and 3 showed higher amounts of newly formed dentin-like structure, that was also thicker, than Group 1 (P < .05). No statistically significant differences in structure thickness were found between Groups 2 and 3. The nature of the structure can differ if rhPDGF or EMP is added to MTA for pulp-capping purposes. Combination of rhPDGF and MTA resulted in a newly formed structure resembling secondary dentin, whereas a combination of EMP and MTA produced a nonporous, highly dense dentinal-like structure associated with significant root-canal obliterations.


Assuntos
Capeamento da Polpa Dentária , Dentina Secundária , Timidina Fosforilase , Compostos de Alumínio , Compostos de Cálcio , Polpa Dentária , Combinação de Medicamentos , Humanos , Óxidos , Regeneração , Silicatos , Microtomografia por Raio-X
2.
PLoS One ; 15(1): e0227549, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31986186

RESUMO

Over-expression of thymidine phosphorylase (TP) plays a key role in many pathological complications, including angiogenesis which leads to cancer cells proliferation. Thus in search of new anticancer agents, a series of 4-hydroxybenzohydrazides (1-29) was synthesized, and evaluated for in vitro thymidine phosphorylase inhibitory activity. Twenty compounds 1-3, 6-14, 16, 19, 22-24, and 27-29 showed potent to weak TP inhibitory activities with IC50 values in the range of 6.8 to 229.5 µM, in comparison to the standards i.e. tipiracil (IC50 = 0.014 ± 0.002 µM) and 7-deazaxanthine (IC50 = 41.0 ± 1.63 µM). Kinetic studies on selected inhibitors 3, 9, 14, 22, 27, and 29 revealed uncompetitive and non-competitive modes of inhibition. Molecular docking studies of these inhibitors indicated that they were able to interact with the amino acid residues present in allosteric site of TP, including Asp391, Arg388, and Leu389. Antiproliferative (cytotoxic) activities of active compounds were also evaluated against mouse fibroblast (3T3) and prostate cancer (PC3) cell lines. Compounds 1, 2, 19, and 22-24 exhibited anti-proliferative activities against PC3 cells with IC50 values between 6.5 to 10.5 µM, while they were largely non-cytotoxic to 3T3 (mouse fibroblast) cells proliferation. Present study thus identifies a new class of dual inhibitors of TP and cancer cell proliferation, which deserves to be further investigated for anti-cancer drug development.


Assuntos
Simulação por Computador , Inibidores Enzimáticos/farmacologia , Hidroxibenzoatos/farmacologia , Neoplasias da Próstata/patologia , Timidina Fosforilase/antagonistas & inibidores , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Humanos , Hidroxibenzoatos/síntese química , Hidroxibenzoatos/metabolismo , Cinética , Masculino , Simulação de Acoplamento Molecular , Conformação Proteica , Timidina Fosforilase/química , Timidina Fosforilase/metabolismo
3.
PLoS One ; 14(11): e0225056, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31743355

RESUMO

Natural flora is the richest source of novel therapeutic agents due to their immense chemical diversity and novel biological properties. In this regard, eighteen natural products belonging to different chemical classes were evaluated for their thymidine phosphorylase (TP) inhibitory activity. TP shares identity with an angiogenic protein platelet derived endothelial cell growth factor (PD-ECGF). It assists tumor angiogenesis and is a key player in cancer progression, thus an ideal target to develop anti-angiogenic drugs. Eleven compounds 1-2, 5-10, 11, 15, and 18 showed a good to weak TP inhibitory activity (IC50 values between 44.0 to 420.3 µM), as compared to standards i.e. tipiracil (IC50 = 0.014 ± 0.002 µM) and 7-deazaxanthine (IC50 = 41.0 ± 1.63 µM). Kinetic studies were also performed on active compounds, in order to deduce the mechanism of ligand binding to enzyme. To get further insight into receptor protein (enzyme) and ligand interaction at atomic level, in- sillico studies were also performed. Active compounds were finally evaluated for cytotoxicity test against mouse fibroblast (3T3) cell line. Compound 18 (Masoprocol) showed a significant TP inhibitory activity (IC50 = 44.0 ± 0.5 µM). Kinetic studies showed that it inhibits the enzyme in a competitive manner (Ki = 25.6 ± 0.008 µM), while it adopts a binding pose different than the substrate thymidine. It is further found to be non-toxic in MTT cytotoxicity assay. This is the first report on TP inhibitory activity of several natural compounds, some of which may serve as leads for further research towards drug the development.


Assuntos
Indutores da Angiogênese/farmacologia , Produtos Biológicos/farmacologia , Simulação por Computador , Inibidores Enzimáticos/farmacologia , Modelos Moleculares , Timidina Fosforilase/antagonistas & inibidores , Células 3T3 , Animais , Produtos Biológicos/química , Inibidores Enzimáticos/química , Cinética , Camundongos , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Timidina Fosforilase/metabolismo
4.
Anticancer Res ; 39(8): 4129-4136, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31366497

RESUMO

BACKGROUND/AIM: 5-Aza-2-deoxycytidine (5-Aza-CdR) enhances the sensitivity to 5-fluorouracil (5-FU), but the molecular mechanism is not fully understood. The aim of this study was to investigate the molecular mechanism that enhances the sensitivity to 5-FU treated with 5-Aza-CdR via thymidine phosphorylase (TP). MATERIALS AND METHODS: The sensitivity to drugs was determined on several cancer cell lines by the MTT assay. Protein and mRNA levels were examined by immunoblot and RT-PCR, respectively. Gene silencing, binding of Sp1 to DNA and methylation of DNA was performed by siRNA, ChIP assay and sodium bisulfate genomic sequencing, respectively. RESULTS: Sp1-binding sites in the TP promoter were methylated in epidermoid carcinoma. 5-Aza-CdR demethylated Sp1-binding sites and enhanced sensitivity to 5-FU. CONCLUSION: Demethylation of Sp1-binding sites by 5-Aza-CdR was a key factor enhancing 5-FU sensitivity, which may enable more effective treatments for cancer patients with the combination of 5-Aza-CdR and 5-FU.


Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Metilação de DNA/genética , Resistencia a Medicamentos Antineoplásicos/genética , Fator de Transcrição Sp1/genética , Timidina Fosforilase/genética , Sítios de Ligação/efeitos dos fármacos , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Metilação de DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Decitabina/metabolismo , Fluoruracila/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Humanos , Regiões Promotoras Genéticas/efeitos dos fármacos , RNA Mensageiro/genética , Timidina Fosforilase/química
5.
Ugeskr Laeger ; 181(24)2019 Jun 10.
Artigo em Dinamarquês | MEDLINE | ID: mdl-31267951

RESUMO

In this case report, a 23-year-old normal-functioning young man was repeatedly admitted to the hospital with mal-nutrition and pseudo-obstruction. External ophthalmoplegia, global muscular atrophy and demyelinating sensory-motor-autonomic neuropathy became evident. An MRI showed symmetrical white matter lesions and muscle biopsy atrophic muscle fibres. A TYMP mutation confirmed the diagnosis, and the patient had a rapidly fatal disease course. Mitochondrial neuro-gastro-intestinal encephalo-myopathy is rare and often overlooked. In less advanced disease, stem cell transplantation can correct thymidine phosphorylase deficiency.


Assuntos
Caquexia , Pseudo-Obstrução Intestinal , Encefalomiopatias Mitocondriais , Distrofia Muscular Oculofaríngea , Caquexia/genética , Evolução Fatal , Humanos , Pseudo-Obstrução Intestinal/complicações , Masculino , Encefalomiopatias Mitocondriais/complicações , Distrofia Muscular Oculofaríngea/complicações , Mutação , Timidina Fosforilase , Adulto Jovem
6.
Am J Health Syst Pharm ; 76(6): 339-348, 2019 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361848

RESUMO

PURPOSE: The pharmacology, pharmacokinetics, clinical efficacy, safety, dosing, and place in therapy of trifluridine-tipiracil are reviewed. SUMMARY: Trifluridine-tipiracil is an oral antineoplastic agent consisting of trifluridine (a trifluorothymidine, a thymidine-based nucleoside analog) and tipiracil (a thymidine phosphorylase inhibitor), at a molar ratio of 1:0.5. Tipiracil blocks the degradation of trifluridine by thymidine phosphorylase, which improves the bioavailability of trifluridine and allows for oral administration. A Phase III study comparing trifluridine-tipiracil versus placebo in metastatic colorectal cancer (mCRC) patients refractory to or intolerant of standard therapy (n = 800) showed a benefit in overall survival (the primary endpoint) and progression-free survival compared with placebo. The most common grade ≥ 3 adverse events in trifluridine-tipiracil groups in Phase II and III trials were neutropenia, anemia, and leukopenia. The recommended dose of trifluridine-tipiracil is 35 mg/m2 twice a day after meals in a 28-day cycle comprising 2 weeks of 5 days of treatment and 2 days of rest (days 1-5 and 8-12 [every] 28 days), followed by 2 weeks of rest. Trifluridine-tipiracil is approved for the treatment of patients with mCRC previously treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, an antivascular endothelial growth factor biological therapy and, if RAS wild-type, an antiepidermal growth factor receptor therapy. CONCLUSION: Trifluridine-tipiracil is a new treatment option for patients with mCRC who have received at least 2 prior lines of standard chemotherapy (including fluoropyrimidine, oxaliplatin, irinotecan, bevacizumab, and an antiepidermal growth factor receptor antibody in patients with KRAS wild-type tumors). Ongoing trials are investigating trifluridine/tipiracil in combination with other anticancer agents for mCRC and its use in other malignancies, such as metastatic gastric cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Pirrolidinas/farmacologia , Trifluridina/farmacologia , Uracila/análogos & derivados , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ensaios Clínicos como Assunto , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Combinação de Medicamentos , Humanos , Intervalo Livre de Progressão , Pirrolidinas/uso terapêutico , Timidina Fosforilase/antagonistas & inibidores , Timidina Fosforilase/metabolismo , Trifluridina/uso terapêutico , Uracila/farmacologia , Uracila/uso terapêutico
7.
Molecules ; 24(6)2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30871147

RESUMO

We have synthesized quinoxaline analogs (1⁻25), characterized by ¹H-NMR and HREI-MS and evaluated for thymidine phosphorylase inhibition. Among the series, nineteen analogs showed better inhibition when compared with the standard inhibitor 7-Deazaxanthine (IC50 = 38.68 ± 4.42 µM). The most potent compound among the series is analog 25 with IC50 value 3.20 ± 0.10 µM. Sixteen analogs 1, 2, 3, 4, 5, 6, 7, 12, 13, 14, 15, 16, 17, 18, 21 and 24 showed outstanding inhibition which is many folds better than the standard 7-Deazaxanthine. Two analogs 8 and 9 showed moderate inhibition. A structure-activity relationship has been established mainly based upon the substitution pattern on the phenyl ring. The binding interactions of the active compounds were confirmed through molecular docking studies.


Assuntos
Inibidores Enzimáticos/síntese química , Quinoxalinas/síntese química , Timidina Fosforilase/antagonistas & inibidores , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Estrutura Molecular , Espectroscopia de Prótons por Ressonância Magnética , Quinoxalinas/química , Quinoxalinas/farmacologia , Relação Estrutura-Atividade
8.
Hum Gene Ther ; 30(8): 985-998, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30900470

RESUMO

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a devastating disease caused by mutations in TYMP, which encodes thymidine phosphorylase (TP). In MNGIE patients, TP dysfunction results in systemic thymidine and deoxyuridine overload, which interferes with mitochondrial DNA replication. Preclinical studies have shown that gene therapy using a lentiviral vector targeted to hematopoietic stem cells or an adeno-associated virus (AAV) vector transcriptionally targeted to liver are feasible approaches to treat MNGIE. Here, we studied the effect of various promoters (thyroxine-binding globulin [TBG], phosphoglycerate kinase [PGK], hybrid liver-specific promoter [HLP], and alpha-1-antitrypsin [AAT]) and DNA configuration (single stranded or self complementary) on expression of the TYMP transgene in the AAV8 serotype in a murine model of MNGIE. All vectors restored liver TP activity and normalized nucleoside homeostasis in mice. However, the liver-specific promoters TBG, HLP, and AAT were more effective than the constitutive PGK promoter, and the self-complementary DNA configuration did not provide any therapeutic advantage over the single-stranded configuration. Among all constructs, only AAV-AAT was effective in all mice treated at the lowest dose (5 × 1010 vector genomes/kg). As use of the AAT promoter will likely minimize the dose needed to achieve clinical efficacy as compared to the other promoters tested, we propose using the AAT promoter in the vector eventually designed for clinical use.


Assuntos
Dependovirus/genética , Expressão Gênica , Terapia Genética , Vetores Genéticos/genética , Encefalomiopatias Mitocondriais/genética , Encefalomiopatias Mitocondriais/terapia , Regiões Promotoras Genéticas , alfa 1-Antitripsina/genética , Animais , Modelos Animais de Doenças , Ordem dos Genes , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Homeostase , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Knockout , Mitocôndrias Hepáticas/genética , Mitocôndrias Hepáticas/metabolismo , Encefalomiopatias Mitocondriais/metabolismo , Timidina Fosforilase/genética , Transdução Genética , alfa 1-Antitripsina/metabolismo
9.
Int J Biochem Cell Biol ; 110: 122-129, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30849523

RESUMO

Thymidine phosphorylase (TP; EC 2.4.2.4) catalyzes the reversible phosphorolysis of thymidine, deoxyuridine, and their analogues to their respective nucleobases and 2-deoxy-α-d-ribose-1-phosphate (dRib-1-P). TP is a key enzyme in the pyrimidine salvage pathways. Activity of the enzyme is crucial in angiogenesis, cancer chemotherapy, radiotherapy, and tumor imaging, Nevertheless, a complete set of kinetic parameters has never been reported for any human TP. This study describes the kinetic mechanism and regulation of native human hepatic TP. The liver is a main site of pyrimidine metabolism and contains high levels of TP. Initial velocity and product inhibition studies demonstrated that the basic mechanism of this enzyme is a sequential random bi-bi mechanism. Initial velocity studies showed an intersecting pattern, consistent with substrate-enzyme-co-substrate complex formation, and a binding pattern indicating that the binding of the substrate interferes with the binding of the co-substrate and vice versa. Estimated kinetic parameters were KThymidine = 284 ± 55, KPi = 5.8 ± 1.9, KThymine = 244 ± 69, and KdRib-1-P = 90 ± 33 µM. Thymine was a product activator, but becomes a substrate inhibitor at concentrations eight times higher than its Km. dRib-1-P was a non-competitive product inhibitor of the forward reaction. It bounded better to the Enzyme●Pi complex than the free enzyme, but had better affinity to the free enzyme than the Enzyme●Thymidine complex. In the reverse reaction, dRib-1-P enhanced the binding of thymine. The enhancement of the thymine binding along with the fact that dRib-1-P was a non-competitive product inhibitor suggests the presence of another binding site for dRib-1-P on the enzyme.


Assuntos
Fígado/enzimologia , Timidina Fosforilase/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Cinética , Fosfatos/metabolismo , Ribosemonofosfatos/metabolismo , Ribosemonofosfatos/farmacologia , Especificidade por Substrato , Timidina/metabolismo , Timidina Fosforilase/antagonistas & inibidores , Timina/metabolismo , Timina/farmacologia
10.
Toxicology ; 417: 54-63, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30796972

RESUMO

Salinomycin is a polyether ionophore antibiotic having anti-tumorigenic property in various types of cancer. Elevated thymidine phosphorylase (TP) levels, a key enzyme in the pyrimidine nucleoside salvage pathway, are associated with an aggressive disease phenotype and poor prognoses. Heat shock protein 90 (Hsp90) is a ubiquitous molecular chaperone that is responsible for the stabilization and maturation of many oncogenic proteins. In this study, we report whether Hsp90 inhibitor 17-AAG could enhance salinomycin-induced cytotoxicity in NSCLC cells through modulating TP expression in two non-small-cell lung cancer (NSCLC) cell lines, A549 and H1975. We found that salinomycin increased TP expression in a MKK3/6-p38 MAPK activation manner. Knockdown of TP using siRNA or inactivation of p38 MAPK by pharmacological inhibitor SB203580 enhanced the cytotoxic and growth inhibition effects of salinomycin. In contrast, enforced expression of MKK6E (a constitutively active form of MKK6) reduced the cytotoxicity and cell growth inhibition of salinomycin. Moreover, Hsp90 inhibitor 17-AAG enhanced cytotoxicity and cell growth inhibition of salinomycin in NSCLC cells, which were associated with down-regulation of TP expression and inactivation of p38 MAPK. Together, the Hsp90 inhibition induced TP down-regulation involved in enhancing the salinomycin-induced cytotoxicity in A549 and H1975 cells.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/enzimologia , Citotoxinas/toxicidade , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias Pulmonares/enzimologia , Piranos/toxicidade , Timidina Fosforilase/antagonistas & inibidores , Células A549 , Antineoplásicos/toxicidade , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Regulação Enzimológica da Expressão Gênica , Proteínas de Choque Térmico HSP90/biossíntese , Humanos , Timidina Fosforilase/biossíntese , Timidina Fosforilase/genética
11.
Orphanet J Rare Dis ; 14(1): 33, 2019 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-30736844

RESUMO

BACKGROUND: MNGIE is a rare and fatal disease in which absence of the enzyme thymidine phosphorylase induces systemic accumulation of thymidine and deoxyuridine and secondary mitochondrial DNA alterations. Gastrointestinal (GI) symptoms are frequently reported in MNGIE patients, however, they are not resolved with the current treatment interventions. Recently, our understanding of the GI pathology has increased, which rationalizes the pursuit of more targeted therapeutic strategies. In particular, interstitial cells of Cajal (ICC) play key roles in GI physiology and are involved in the pathogenesis of the GI dysmotility. However, understanding of the triggers of ICC deficits in MNGIE is lacking. Herein, we review the current knowledge about the pathology of GI dysmotility in MNGIE, discuss potential mechanisms in relation to ICC loss/dysfunction, remark on the limited contribution of the current treatments, and propose intervention strategies to overcome ICC deficits. Finally, we address the advances and new research avenues offered by organoids and tissue engineering technologies, and propose schemes to implement to further our understanding of the GI pathology and utility in regenerative and personalized medicine in MNGIE. CONCLUSION: Interstitial cells of Cajal play key roles in the physiology of the gastrointestinal motility. Evaluation of their status in the GI dysmotility related to MNGIE would be valuable for diagnosis of MNGIE. Understanding the underlying pathological and molecular mechanisms affecting ICC is an asset for the development of targeted prevention and treatment strategies for the GI dysmotility related to MNGIE.


Assuntos
Gastroenteropatias/patologia , Células Intersticiais de Cajal/patologia , Timidina Fosforilase/deficiência , Feminino , Gastroenteropatias/metabolismo , Humanos , Células Intersticiais de Cajal/metabolismo , Pseudo-Obstrução Intestinal/metabolismo , Pseudo-Obstrução Intestinal/patologia , Masculino , Distrofia Muscular Oculofaríngea/metabolismo , Distrofia Muscular Oculofaríngea/patologia , Mutação/genética , Timidina Fosforilase/genética , Timidina Fosforilase/metabolismo
12.
Anticancer Res ; 39(2): 1051-1057, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30711994

RESUMO

BACKGROUND/AIM: New drugs for metastatic colorectal cancer (mCRC) have been recently developed for use in later-line chemotherapy and have contributed to further prolongation of the survival of patients. However, in later-line chemotherapy, treatment failure may lead to discontinuation of chemotherapy and the transition to best supportive care. Therefore, a biomarker able to predict the effects of later-line chemotherapy is required. The C-reactive protein-to-albumin ratio (CAR), which is an inflammatory marker, has been reported to correlate with therapeutic outcome in patients with mCRC who underwent first-line chemotherapy. However, the significance of the CAR as a marker for predicting the chemotherapeutic outcome in patients with mCRC treated with later-line chemotherapy is unknown. PATIENTS AND METHODS: We retrospectively reviewed the medical records of 40 patients with mCRC who were treated with trifluridine/thymidine phosphorylase inhibitor (FTD/TPI) as a later-line chemotherapy. The CAR was calculated from the blood samples obtained within 1 week before the initiation of FTD/TPI by dividing the serum C-reactive protein level by the serum albumin level. RESULTS: According to the receiver operating characteristic curve analysis, we set 0.122 as the CAR cut-off, and patients were classified into groups with high or low CAR. The low-CAR group had a significantly higher disease control rate than the high-CAR group. The progression-free and overall survival rates were significantly better in the low-CAR group than in the high-CAR group. A high-CAR was associated with a greater number of prior regimens, higher serum lactate dehydrogenase level and more organs with metastases, considered to be correlated with the rate of disease progression. However, no significant differences were observed in the incidence of grade 3 or more adverse events, the relative dose intensity, or the rate of discontinuing chemotherapy between the two groups. CONCLUSION: The CAR may be a useful indicator for predicting the chemotherapeutic outcome in patients with mCRC treated with FTD/TPI as a late-line chemotherapy. The correlation between a high-CAR and poor prognosis was presumed to be due to the rate of cancer growth and increased resistance to chemotherapy rather than an insufficient dose of the drug.


Assuntos
Albuminas/análise , Antineoplásicos/uso terapêutico , Proteína C-Reativa/análise , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Trifluridina/uso terapêutico , Idoso , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Inflamação , Estimativa de Kaplan-Meier , L-Lactato Desidrogenase/metabolismo , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Prognóstico , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Timidina Fosforilase/antagonistas & inibidores , Resultado do Tratamento
13.
BMC Gastroenterol ; 19(1): 11, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30646848

RESUMO

BACKGROUND: Mitochondrial neurogastrointestinal encephalopathy (MNGIE), due to mutations in TYMP, often presents with gastrointestinal symptoms. Two sisters, initially managed for Crohn's disease based upon clinical, imaging and pathological findings, were later found to have MNGIE. The cases provide novel clinicopathological insight, for two further reasons: both sisters remain ambulant and in employment in their late 20s and 30s; diagnosis in one sister was made after a suspected azathioprine-precipitated acute illness. CASE PRESENTATION: A 25-year-old female presented with diarrhoea, vomiting, abdominal pain, and bloating. Faecal calprotectin, colonic biopsies and magnetic resonance enterography were consistent with a diagnosis of Crohn's disease. Azathioprine initiation preceded admission with a sore throat, headache, myalgia, and pyrexia. Withdrawal led to rapid clinical improvement. MRI brain revealed persistent, extensive white matter changes. Elevated plasma and urine thymidine and deoxyuridine, and genetic testing for TYMP variants, confirmed MNGIE. Testing of the patient's sister, also diagnosed with Crohn's disease, revealed identical variants. In this context, retrospective review of colonic biopsies identified histological findings suggestive of MNGIE. CONCLUSIONS: Azathioprine interference in nucleic acid metabolism may interact with the mitochondrial DNA depletion of MNGIE. Nucleotide supplementation, proposed for treatment by manipulating mitochondrial nucleoside pools, may require caution. The late onset and mild phenotype observed confirms presentation can occur later in life, and may reflect residual thymidine phosphorylase activity. Clinicians should consider measuring plasma thymidine levels in suspected Crohn's disease to rule out MNGIE, particularly if white matter abnormalities are identified on neuroimaging.


Assuntos
Doença de Crohn/diagnóstico , Gastroenteropatias/diagnóstico , Gastroenteropatias/patologia , Encefalomiopatias Mitocondriais/diagnóstico , Encefalomiopatias Mitocondriais/patologia , Adulto , Idade de Início , Azatioprina/efeitos adversos , Desoxiuridina/sangue , Desoxiuridina/urina , Diagnóstico Diferencial , Feminino , Humanos , Fenótipo , Mutação Puntual , Estudos Retrospectivos , Timidina/sangue , Timidina/urina , Timidina Fosforilase/genética , Substância Branca/patologia
14.
Expert Opin Pharmacother ; 20(4): 399-409, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30649964

RESUMO

INTRODUCTION: Capecitabine is an oral prodrug of 5-fluorouracil (5-FU) which is converted to 5FU by a series of reactions catalyzed by different enzymes, the last of the enzymes being thymidine phosphorylase (TP). TP is found to be elevated in tumor cells in comparison to normal cells, which consequently tumor-localizes the production of 5-FU, thereby limiting its systemic toxicity. Today, capecitabine is extensively used for the treatment of many solid malignancies, with a particular focus in breast and gastrointestinal tumors, but also in pancreatic cancer. Areas covered: This review summarizes the pharmacology and the clinical evidence relevant to the use of capecitabine in the treatment of pancreas cancer. The authors provide, furthermore, provide their expert perspectives on its use. Expert opinion: Capecitabine has the advantage over other therapeutics in so much that it has both convenient oral administration and a favorable toxicity profile. Current data has promised the use of capecitabine in all stages of pancreatic cancer. However, predictive markers for outcome and toxicity remain to be validated.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Capecitabina/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Neoplasias Gastrointestinais/tratamento farmacológico , Humanos , Pró-Fármacos , Timidina Fosforilase/metabolismo
15.
Bioorg Chem ; 85: 209-220, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30634096

RESUMO

Thymidine phosphorylase (TP) is over expressed in several solid tumors and its inhibition can offer unique target suitable for drug discovery in cancer. A series of 1,2,4-triazoles 3a-3l has been synthesized in good yields and subsequently inhibitory potential of synthesized triazoles 3a-3l against thymidine phosphorylase enzyme was evaluated. Out of these twelve analogs five analogues 3b, 3c, 3f, 3l and 3l exhibited a good inhibitory potential against thymidine phosphorylase. Inhibitory potential in term of IC50 values were found in the range of 61.98 ±â€¯0.43 to 273.43 ±â€¯0.96 µM and 7-Deazaxanthine was taken as a standard inhibitor with IC50 = 38.68 ±â€¯4.42 µM. Encouraged by these results, more analogues 1,2,4-triazole-3-mercaptocarboxylic acids 4a-4g were synthesized and their inhibitory potential against thymidine phosphorylase was evaluated. In this series, six analogues 4b-4g exhibited a good inhibitory potential in the range of 43.86 ±â€¯1.11-163.43 ±â€¯2.03 µM. Angiogenic response of 1,2,4-triazole acid 4d was estimated using the chick chorionic allantoic membrane (CAM) assay. In the light of these findings, structure activity relationship and molecular docking studies of selected triazoles to determine the key binding interactions was discussed. Docking studies demonstrate that synthesized analogues interacted with active site residues of thymidine phosphorylase enzyme through π-π stacking, thiolate and hydrogen bonding interactions.


Assuntos
Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , Timidina Fosforilase/antagonistas & inibidores , Triazóis/farmacologia , Inibidores da Angiogênese/síntese química , Inibidores da Angiogênese/metabolismo , Inibidores da Angiogênese/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Domínio Catalítico , Galinhas , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Escherichia coli/enzimologia , Hidrogéis/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade , Timidina Fosforilase/química , Timidina Fosforilase/metabolismo , Engenharia Tecidual/métodos , Triazóis/síntese química , Triazóis/metabolismo
16.
J Med Chem ; 62(3): 1231-1245, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30615449

RESUMO

Overexpressed human thymidine phosphorylase (hTP) has been associated with cancer aggressiveness and poor prognosis by triggering proangiogenic and antiapoptotic signaling. Designed as transition-state analogues by mimicking the oxacarbenium ion, novel pyrimidine-2,4-diones were synthesized and evaluated as inhibitors of hTP activity. The most potent compound (8g) inhibited hTP in the submicromolar range with a noncompetitive inhibition mode with both thymidine and inorganic phosphate substrates. Furthermore, compound 8g was devoid of apparent toxicity to a panel of mammalian cells, showed no genotoxicity signals, and had low probability of drug-drug interactions and moderate in vitro metabolic rates. Finally, treatment with 8g (50 mg/(kg day)) for 2 weeks (5 days/week) significantly reduced tumor growth using an in vivo glioblastoma model. To the best of our knowledge, this active compound is the most potent in vitro hTP inhibitor with a kinetic profile that cannot be reversed by the accumulation of any enzyme substrates.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Glioblastoma/tratamento farmacológico , Timidina Fosforilase/antagonistas & inibidores , Animais , Área Sob a Curva , Linhagem Celular , Linhagem Celular Tumoral , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/uso terapêutico , Meia-Vida , Humanos
17.
Phytomedicine ; 53: 28-36, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30668408

RESUMO

BACKGROUND: Excision repair cross-complementary 1 (ERCC1) overexpression in lung cancer cells is strongly correlated with its resistance to platinum-based chemotherapy. Overexpression of thymidine phosphorylase (TP) reverts platinum-induced cancer cell death. PURPOSE: Curcumin has been reported to enhance antitumor properties through the suppression of TP and ERCC1 in non-small cell lung carcinoma cells (NSCLC). Nevertheless, whether two other curcuminoids, demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) from Curcuma longa demonstrate antitumor activity like that of curcumin remain unknown. METHODS: MTT assay was conducted to determine the cell cytotoxicity. Western blotting was used to determine the protein expressions. Docking is the virtual screening of a database of compounds and predicting the strongest binders based on various scoring functions. BIOVIA Discovery Studio 4.5 (D.S. 4.5) were used for docking. RESULTS: Firstly, when compared with curcumin and BDMC, DMC exhibited the most potent cytotoxic effect on NSCLC, most importantly, MRC-5, a lung fetal fibroblast, was insensitive to DMC (under 30 µM). Secondly, DMC alone significantly inhibited on-target cisplatin (CDDP) resistance protein, ERCC1, via PI3K-Akt-snail pathways, and TP protein expression in A549 cells. Thirdly, DMC treatment markedly increased post-target CDDP resistance pathway including Bax and cytochrome c. DMC significantly decreased Bcl-2 protein expressions. Finally, MTT assay indicated that DMC significantly increased CDDP-induced cytotoxicity and was confirmed with an increased Bax/Bcl-2 ratio, indicating upregulation of caspase-3. CONCLUSIONS: We concluded that enhancement of the cytotoxicity to CDDP by coadminstration with DMC was mediated by down-regulation of the expression of TP and ERCC1, regulated by PI3K-Akt-Snail pathway inactivation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Curcumina/análogos & derivados , Proteínas de Ligação a DNA/metabolismo , Endonucleases/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Células A549 , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Cisplatino/farmacologia , Curcuma/química , Curcumina/administração & dosagem , Curcumina/química , Curcumina/metabolismo , Curcumina/farmacologia , Diarileptanoides , Regulação para Baixo/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Simulação de Acoplamento Molecular , Fosfatidilinositol 3-Quinases/metabolismo , Timidina Fosforilase/antagonistas & inibidores , Timidina Fosforilase/metabolismo
18.
Cell Death Dis ; 10(2): 43, 2019 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-30674871

RESUMO

Tumor progression is dependent on metabolic reprogramming. Metastasis and vasculogenic mimicry (VM) are typical characteristics of tumor progression. The relationship among metastasis, VM, and metabolic reprogramming remains unclear. In this study, we identified the novel role of Twist1, a VM regulator, in the transcriptional regulation of thymidine phosphorylase (TP) expression. TP promoted the extracellular metabolism of thymidine into ATP and amino acids through the pentose Warburg effect by coupling the pentose phosphate pathway and glycolysis. Moreover, Twist1 relied on TP-induced metabolic reprogramming to promote hepatocellular carcinoma (HCC) metastasis and VM formation mediated by VE-Cad, VEGFR1, and VEGFR2 in vitro and in vivo. The TP inhibitor tipiracil reduced the effect of TP on promoting HCC VM formation and metastasis. Hence, TP, when transcriptionally activated by Twist1, promotes HCC VM formation and metastasis through the pentose Warburg effect and contributes to tumor progression.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Timidina Fosforilase/uso terapêutico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Progressão da Doença , Humanos , Neoplasias Hepáticas/patologia , Timidina Fosforilase/farmacologia , Transfecção
19.
Mol Cancer Ther ; 18(3): 541-555, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30642883

RESUMO

Pyrimethamine (Pyr), an antimalarial drug that targeting plasmodium dihydrofolate reductase (pDHFR), has been proved to have antitumor activity. However, its direct target on cancer cells remains unclear. Methotrexate (MTX) is a widely used anticancer drug that blocks human dihydrofolate reductase (hDHFR). In this work, we examined the anticancer effects of Pyr in vitro and in vivo Our results showed that hDHFR and pDHFR have similar secondary and three-dimensional structures and that Pyr can inhibit the activity of hDHFR in lung cancer cells. Although Pyr and MTX can inhibit the proliferation of lung cancer cells by targeting DHFR, only Pyr can inhibit the epithelial-mesenchymal transition (EMT), metastasis and invasion of lung cancer cells. These results indicated that hDHFR is not the only target of Pyr. We further found that thymidine phosphorylase (TP), an enzyme that is closely associated with the EMT of cancer cells, is also a target protein of Pyr. The data retrieved from the Cancer Genome Atlas (TCGA) database revealed that TP overexpression is associated with poor prognosis of patients with lung cancer. In conclusion, Pyr plays a dual role in antitumor proliferation and metastasis by targeting DHFR and TP. Pyr may have potential clinical applications for the treatment of lung cancer.


Assuntos
Neoplasias Pulmonares/tratamento farmacológico , Pirimetamina/química , Tetra-Hidrofolato Desidrogenase/química , Timidina Fosforilase/química , Antimaláricos/química , Antimaláricos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Metotrexato/química , Metotrexato/farmacologia , Conformação Molecular , Metástase Neoplásica , Estrutura Secundária de Proteína , Pirimetamina/farmacologia , Tetra-Hidrofolato Desidrogenase/genética , Timidina Fosforilase/antagonistas & inibidores , Timidina Fosforilase/genética
20.
Gastric Cancer ; 22(3): 497-505, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30276573

RESUMO

BACKGROUND: 5FU can be converted to its active metabolite fluoro-deoxyuridine monophosphate (FdUMP) through two pathways: the orotate phosphoribosyl transferase-ribonucleotide reductase (OPRT-RR) pathway and the thymidine phosphorylase-thymidine kinase (TP-TK) pathway. We investigated the mechanism underlying 5FU-resistance, focusing on the changes in the 5FU metabolisms. METHODS: MKN45 and 5FU-resistant MKN45/F2R cells were treated with 5FU or fluoro-deoxyuridine (FdU) in combination with hydroxyurea (HU) or tipiracil (TPI). The amount of FdUMP was determined by the density of the upper band of thymidylate synthase on Western blotting. RESULTS: The MKN45/F2R cells exhibited 5FU resistance (37.1-fold) and showed decreased OPRT and increased TP levels. In both cells, the FdUMP after treatment with 5FU was decreased when RR was inhibited by HU but not when TP was inhibited by TPI. A metabolome analysis revealed the loss of intracellular deoxyribose 1-phosphate (dR1P) in both cells, indicating that FdUMP was synthesized from 5FU only through the OPRT-RR pathway because of the loss of dR1P. After the knockdown of TK, the FdUMP after treatment with FdU was decreased in MKN45 cells. However, it was not changed in MKN45/F2R cells. Furthermore, TP inhibition caused an increase in FdUMP after treatment with 5FU or FdU and reversed the 5FU resistance in MKN45/F2R cells, indicating that FdUMP was reduced through the TP-TK pathway in MKN45/F2R cells. CONCLUSIONS: In MKN45/F2R cells, the reduction of FdUMP through the TP-TK pathway caused 5FU resistance, and the inhibition of TP reversed the resistance to 5FU, suggesting that the combination of 5FU and TPI is a promising cancer therapy.


Assuntos
Resistencia a Medicamentos Antineoplásicos , Fluoruracila/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Timidina Fosforilase/antagonistas & inibidores , Antimetabólitos Antineoplásicos/farmacologia , Apoptose , Proliferação de Células , Humanos , Orotato Fosforribosiltransferase/antagonistas & inibidores , Orotato Fosforribosiltransferase/genética , RNA Interferente Pequeno/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Timidina Fosforilase/genética , Células Tumorais Cultivadas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA