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1.
Future Oncol ; 19(17): 1165-1174, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37458152

RESUMO

For BRAF V600E-mutated metastatic colorectal cancer (mCRC), the BEACON phase 3 trial showed survival benefit of triplet therapy with cetuximab (anti-EGFR antibody), encorafenib (BRAF inhibitor) and binimetinib (MEK inhibitor) as well as doublet therapy with cetuximab and encorafenib over irinotecan-based chemotherapy plus anti-EGFR antibody. Both regimens are standards of care in Japan, but definite biomarkers for predicting efficacy and selecting treatment remain lacking. The mechanisms underlying resistance to these regimens also warrant urgent exploration to further evolve treatment. This prospective observational/translational study evaluated real-word clinical outcomes with cetuximab and encorafenib with or without binimetinib for BRAF-mutated mCRC patients and investigated biomarkers for response and resistance by collecting blood samples before and after treatment. Clinical Trial Registration: UMIN000045530 (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000051983).


The BEETS trial is a study that looks at how well two combinations of targeted therapies (cetuximab + encorafenib with or without binimetinib) work and how safe they are for patients with advanced colorectal cancer that has a mutation (change) in the BRAF gene. In this trial, patients participate voluntarily instead of being assigned to one of the two therapy groups. When a patient has BRAF-mutated advanced colorectal cancer, it means that the cancer cells in their body have changes in a gene called BRAF. This gene normally produces a protein called BRAF, which is involved in the growth of cells. However, when there is a mutation in this gene, it can cause the production of an overactive BRAF protein, leading to fast and excessive cell growth and division. For patients with BRAF-mutated advanced colorectal cancer, combinations of targeted therapies have been found to be effective as a second- or third-line treatment, based on the results of a phase 3 clinical trial. The main goal of the BEETS trial is to evaluate how well these treatments work and how safe they are when used in real-world clinical practice. Additionally, the study will use laboratory tests (liquid biopsy) to explore new biomarkers that can help predict how well a treatment will work and assist in selecting the most suitable treatment plans. We hope that the findings of this study will contribute to improving the overall management of this specific type of cancer.


Assuntos
Beta vulgaris , Neoplasias do Colo , Neoplasias Colorretais , Neoplasias Retais , Humanos , Proteínas Proto-Oncogênicas B-raf/genética , Cetuximab/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias do Colo/tratamento farmacológico , Neoplasias Retais/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Mutação , Estudos Observacionais como Assunto
2.
Future Oncol ; 18(20): 2465-2473, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35535555

RESUMO

Standard-of-care for resectable gastric/gastroesophageal junction cancer includes surgery and neoadjuvant-adjuvant 5-fluorouracil-leucovorin-oxaliplatin-docetaxel (FLOT) chemotherapy. Early-phase clinical studies support further clinical development of the immune checkpoint inhibitor (ICI); durvalumab, an anti-PD-L1 antibody, in patients with gastric/gastroesophageal junction cancer. Accumulating evidence indicates that ICIs combined with FLOT chemotherapy improve clinical outcomes in patients with advanced or metastatic cancer. We describe the rationale for and the design of MATTERHORN, a randomized, double-blind, placebo-controlled, phase III study investigating the efficacy and safety of neoadjuvant-adjuvant durvalumab and FLOT chemotherapy followed by adjuvant durvalumab monotherapy in patients with resectable gastric/gastroesophageal junction cancer. The planned sample size is 900 patients, the primary end point is event-free survival and safety and tolerability will be evaluated. Clinical trial registration: NCT04592913 (ClinicalTrials.gov).


Assuntos
Adenocarcinoma , Neoplasias Gástricas , Adenocarcinoma/patologia , Anticorpos Monoclonais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ensaios Clínicos Fase III como Assunto , Junção Esofagogástrica/patologia , Fluoruracila/efeitos adversos , Humanos , Terapia Neoadjuvante , Ensaios Clínicos Controlados Aleatórios como Assunto , Neoplasias Gástricas/patologia
3.
Future Oncol ; 17(19): 2431-2438, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33764163

RESUMO

Limited data are available regarding the efficacy of nutrition support in advanced gastric cancer (AGC) patients receiving a standard second-line combination chemotherapy. The BALAST study is conducted as a prospective, multicenter observational study to evaluate the efficacy of nutrition support for patients with AGC treated with ramucirumab plus taxane as second-line treatment. As part of the routine care, patients who are malnourished or at risk of malnutrition will receive nutrition support from dietitians. We will enroll a total of 26 patients to estimate weight control rate at 12 weeks as primary end point. This study will generate valuable data reinforcing the role of nutrition support therapy for AGC patients receiving second-line chemotherapy.


Lay abstract Various guidelines recommend that nutrition support therapy should be considered if cancer patients are malnourished or at risk of malnutrition. Several studies have revealed that body weight loss, which is an important factor in determining the nutrition status, may predict survival during second-line standard chemotherapy with ramucirumab and a taxane for advanced gastric cancer (AGC) patients. However, limited data are available regarding the efficacy of nutrition support in AGC patients receiving ramucirumab and a taxane. This study is conducted as a prospective, multicenter observational study to evaluate the efficacy of nutrition support for Japanese patients with AGC treated with ramucirumab and a taxane. This study will generate valuable data reinforcing the role of nutrition support therapy for AGC patients in second-line treatment. Clinical trial registration: UMIN000037867.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Desnutrição/terapia , Neoplasias Gástricas/tratamento farmacológico , Adulto , Manutenção do Peso Corporal/efeitos dos fármacos , Seguimentos , Humanos , Masculino , Desnutrição/diagnóstico , Desnutrição/etiologia , Estudos Multicêntricos como Assunto , Estadiamento de Neoplasias , Terapia Nutricional , Estado Nutricional/efeitos dos fármacos , Estudos Observacionais como Assunto , Paclitaxel/administração & dosagem , Paclitaxel/efeitos adversos , Intervalo Livre de Progressão , Estudos Prospectivos , Neoplasias Gástricas/complicações , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/mortalidade , Ramucirumab
4.
BMC Cancer ; 20(1): 687, 2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703200

RESUMO

BACKGROUND: First-line treatment with FOLFOXIRI plus bevacizumab (BEV) is highly effective and regarded as one of the standards-of-care for patients with metastatic colorectal cancer (mCRC), despite the high incidence of neutropenia and diarrhea as side effects. AXEPT, an Asian phase III study, showed that modified CAPIRI+BEV [capecitabine (CAP: 1600 mg/m2), irinotecan (IRI: 200 mg/m2), and BEV (7.5 mg/m2)] was non-inferior to FOLFIRI+BEV as a second-line therapy for mCRC patients and was associated with a lower incidence of hematologic toxicities. Thus, a reduced dose of the CAP and IRI regimen in combination with oxaliplatin (OX) and BEV (CAPOXIRI+BEV) may be more feasible than FOLFOXIRI+BEV, without compromising efficacy. METHODS: QUATTRO-II is an open-label, multicenter, randomized phase II study. In Step 1, the recommended doses of OX and IRI will be investigated as a safety lead-in. In Step 2, patients will be randomized to the recommended dose of either CAPOXIRI+BEV or FOLFOXIRI+BEV. Induction triplet chemotherapy plus BEV treatments will be administered for up to 4 months followed by fluoropyrimidine plus BEV maintenance. The primary endpoint is progression-free survival (PFS). The similarity in PFS between the two arms will be evaluated by observing whether the point estimate of hazard ratio (HR) for PFS falls between 0.80 and 1.25. Ensuring a 70% probability that the observed HR will be "0.8 < HR < 1.25" under the assumption of the true HR of 1.0, and 100 patients will be evaluated during the 3-year study period. Secondary endpoints include overall survival, overall response rate, safety, and patient reported outcome (PRO) (FACT/GOG-Ntx4). DISCUSSION: Considering the lower incidence of hematologic toxicities with modified CAPIRI+BEV than with FOLFIRI+BEV, CAPOXIRI+BEV may be a promising treatment option if sufficient efficacy and lower hematologic toxicities are indicated in this study. Additionally, a lower incidence of peripheral sensory neuropathy (PSN) reported following CAPEOX treatment compared to that after FOLFOX in ACHIEVE, an adjuvant phase III trial, suggest that CAPOXIRI+BEV can mitigate OX-induced PSN. TRIAL REGISTRATION: Clinicaltrials.gov NCT04097444 . Registered September 20, 2019, https://clinicaltrials.gov/ct2/show/study/NCT04097444 / Japan Registry of Clinical Trials jRCTs041190072. Registered October 9, 2019.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bevacizumab/administração & dosagem , Camptotecina/análogos & derivados , Neoplasias do Colo/tratamento farmacológico , Desoxicitidina/análogos & derivados , Fluoruracila/análogos & derivados , Neoplasias Retais/tratamento farmacológico , Adenocarcinoma/patologia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Camptotecina/administração & dosagem , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Desoxicitidina/administração & dosagem , Esquema de Medicação , Fluoruracila/administração & dosagem , Genes ras , Glucuronosiltransferase/genética , Humanos , Leucovorina/administração & dosagem , Compostos Organoplatínicos/administração & dosagem , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Retais/genética , Neoplasias Retais/patologia
5.
Biomed Rep ; 11(4): 171-180, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31565223

RESUMO

To enable the widespread application of genomic medicine, the extraction of genomic DNA from thin sections of archived formalin-fixed and paraffin-embedded (FFPE) tissue blocks for next-generation sequencing (NGS) is often necessary. However, there are currently no guidelines available on which specific regions of the microtome sections to use for macrodissection with respect to the histopathological factors observed under microscopic examination. The aim of this study was to clarify the relationship between histopathological factors and DNA quality, and to standardize the macrodissection method for more efficient implementation of NGS. FFPE tissue specimens of 218 patients from the Biomarker Research for Anti-EGFR Monoclonal Antibodies by Comprehensive Cancer Genomics study were used to investigate the relationship between 15 histopathological factors and the quantitative ratio of double-stranded DNA (dsDNA) to total nucleic acids, as well as the ∆ crossing point value of each tissue specimen. Multivariate logistic regression analysis revealed that specimen storage of ≥3 years was negatively associated with dsDNA quality (P=0.0007, OR: 4.30, 95% CI: 1.85-10.04). In contrast, the presence of a mucus pool was positively associated with dsDNA quality (P=0.0308, OR: 0.23, 95% CI: 0.06-0.87). Metastatic tumors and longer specimen storage periods were significantly associated with lower ∆Cp values (P=0.0007, OR: 4.43, 95% CI: 1.87-10.49; and P=0.0003, OR: 5.51, 95% CI: 2.18-13.95, respectively). Therefore, macrodissection should not be performed on specimens exhibiting histopathological factors associated with poor DNA quality. In particular, the use of tissue blocks with a storage period of <3 years allows the extraction of genomic DNA suitable for NGS.

6.
Br J Cancer ; 117(10): 1450-1458, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-28972961

RESUMO

BACKGROUND: Patients with BRAFV600E-mutated metastatic colorectal cancer (mCRC) have a poorer prognosis as well as resistance to anti-EGFR antibodies. However, it is unclear whether BRAF mutations other than BRAFV600E (BRAFnon-V600E mutations) contribute to anti-EGFR antibody resistance. METHODS: This study was composed of exploratory and inference cohorts. Candidate biomarkers identified by whole exome sequencing from super-responders and nonresponders in the exploratory cohort were validated by targeted resequencing for patients who received anti-EGFR antibody in the inference cohort. RESULTS: In the exploratory cohort, 31 candidate biomarkers, including KRAS/NRAS/BRAF mutations, were identified. Targeted resequencing of 150 patients in the inference cohort revealed 40 patients with RAS (26.7%), 9 patients with BRAFV600E (6.0%), and 7 patients with BRAFnon-V600E mutations (4.7%), respectively. The response rates in RAS, BRAFV600E, and BRAFnon-V600E were lower than those in RAS/BRAF wild-type (2.5%, 0%, and 0% vs 31.9%). The median PFS in BRAFnon-V600E mutations was 2.4 months, similar to that in RAS or BRAFV600E mutations (2.1 and 1.6 months) but significantly worse than that in wild-type RAS/BRAF (5.9 months). CONCLUSIONS: Although BRAFnon-V600E mutations identified were a rare and unestablished molecular subtype, certain BRAFnon-V600E mutations might contribute to a lesser benefit of anti-EGFR monoclonal antibody treatment.


Assuntos
Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/genética , Neoplasias Colorretais/genética , Resistencia a Medicamentos Antineoplásicos/genética , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Adulto , Idoso , Anticorpos Monoclonais/uso terapêutico , Cetuximab/uso terapêutico , Estudos de Coortes , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/mortalidade , Intervalo Livre de Doença , Receptores ErbB/antagonistas & inibidores , Feminino , Genômica , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Panitumumabe
7.
Int J Clin Oncol ; 21(5): 890-898, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26980212

RESUMO

PURPOSE: Our intent was to compare survival following neoadjuvant chemotherapy followed by surgery versus chemoradiotherapy (CRT) among patients with potentially resectable esophageal squamous cell carcinoma. METHODS: Information about 406 consecutive esophageal cancer patients with resectable disease who underwent surgery with neoadjuvant chemotherapy consisting of cisplatin plus 5-fluorouracil or who underwent definitive CRT was reviewed. The survival outcomes were analyzed using the Kaplan-Meier method and propensity score-adjusted Cox proportional hazards models. Relevant variables were included in the propensity score model. RESULTS: Overall, 206 patients planned to undergo surgery (S group) and 200 patients planned to undergo CRT (CRT group). In the unadjusted situation, progression-free survival and overall survival did not differ statistically between the groups. After matching, both survival outcomes were better in the S group compared to the CRT group. Subanalysis showed both survival outcomes were better in the S group for patients with only stage III disease. However, survival outcomes for stages I, II, and IV were not significantly different between treatment groups. CONCLUSIONS: Among patients with resectable disease, survival outcomes in the S group were favored over those of the CRT group. These results indicate that different therapeutic strategies should be used for stage III esophageal cancer than for other stages.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Quimiorradioterapia , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/terapia , Esofagectomia , Idoso , Quimioterapia Adjuvante , Cisplatino/administração & dosagem , Intervalo Livre de Doença , Carcinoma de Células Escamosas do Esôfago , Feminino , Fluoruracila/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Pontuação de Propensão , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Taxa de Sobrevida
8.
Lancet Oncol ; 14(13): 1278-86, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24225157

RESUMO

BACKGROUND: Studies done in Asia have shown that a regimen of S-1 plus oxaliplatin (SOX) has promising efficacy and safety in patients with metastatic colorectal cancer. We aimed to establish whether SOX plus bevacizumab is non-inferior to mFOLFOX6 (modified regimen of leucovorin, fluorouracil, and oxaliplatin) plus bevacizumab as first-line chemotherapy for metastatic colorectal cancer. METHODS: We undertook an open-label, non-inferiority, randomised phase 3 trial in 82 sites in Japan. We enrolled individuals aged 20-80 years who had metastatic colorectal cancer, had an Eastern Cooperative Oncology Group performance status of 0 or 1, had assessable lesions, had received no previous chemotherapy or radiotherapy, could take drugs orally, and had adequate organ function. Eligible patients were randomly assigned (1:1) to receive either mFOLFOX6 plus bevacizumab (on day 1 of each 2-week cycle, 5 mg/kg intravenous infusion of bevacizumab and a simultaneous intravenous infusion of 85 mg/m(2) oxaliplatin, 200 mg/m(2)l-leucovorin, 400 mg/m(2) bolus fluorouracil, and 2400 mg/m(2) infusional fluorouracil) or SOX plus bevacizumab (on day 1 of each 3-week cycle, 7·5 mg/kg intravenous infusion of bevacizumab and 130 mg/m(2) intravenous infusion of oxaliplatin; assigned dose of S-1 twice a day from after dinner on day 1 to after breakfast on day 15, followed by 7-day break). Randomisation was done centrally with the minimisation method, with stratification by institution and whether postoperative adjuvant chemotherapy had been given. Participants, investigators, and data analysts were not masked to treatment assignment. The primary endpoint was progression-free survival (PFS), which was defined as the interval between enrolment and progressive disease (≥20% increase in sum of longest dimensions of target lesions from baseline, or appearance of new lesions) or death, whichever came first. The primary analysis was done by modified intention to treat. This trial is registered with the Japan Pharmaceutical Information Center, number JapicCTI-090699. FINDINGS: Between Feb 1, 2009, and March 31, 2011, 512 patients underwent randomisation. 256 patients assigned to receive SOX plus bevacizumab and 255 assigned to receive mFOLFOX6 plus bevacizumab were included in the primary analysis. Median PFS was 11·5 months (95% CI 10·7-13·2) in the group assigned to mFOLFOX6 plus bevacizumab and 11·7 months (10·7-12·9) in the group assigned to SOX plus bevacizumab (HR 1·04, 95% CI 0·86-1·27; less than non-inferiority margin of 1·33, pnon-inferiority=0·014). The most common haematological adverse events of grade 3 or higher were leucopenia (21 [8%] of 249 patients given mFOLFOX6 plus bevacizumab included in safety analysis vs six [2%] of 250 given SOX plus bevacizumab; p=0·0029) and neutropenia (84 [34%] vs 22 [9%]; p<0·0001). Grade 3 or higher anorexia (13 [5%] vs three [1%]; p=0·019) and diarrhoea (23 [9%] vs seven [3%]; p=0·0040) were significantly more common in patients given SOX plus bevacizumab than in those given mFOLFOX6 plus bevacizumab. We recorded seven treatment-related deaths (three in the group given mFOLFOX6 plus bevacizumab; four in that given SOX plus bevacizumab). INTERPRETATION: SOX plus bevacizumab is non-inferior to mFOLFOX6 plus bevacizumab with respect to PFS as first-line treatment for metastatic colorectal cancer, and could become standard treatment in Asian populations. FUNDING: Taiho.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab , Quimioterapia Adjuvante , Neoplasias Colorretais/patologia , Intervalo Livre de Doença , Esquema de Medicação , Combinação de Medicamentos , Feminino , Fluoruracila/administração & dosagem , Humanos , Infusões Intravenosas , Japão , Estimativa de Kaplan-Meier , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Compostos Organoplatínicos/administração & dosagem , Oxaliplatina , Ácido Oxônico/administração & dosagem , Tegafur/administração & dosagem , Resultado do Tratamento
9.
Jpn J Clin Oncol ; 36(4): 218-23, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16684860

RESUMO

BACKGROUND: Infusional fluorouracil (5-FU) and leucovorin (LV) with oxaliplatin is one of the current standard regimens for the treatment of patients with metastatic colorectal cancer. Weekly bolus 5-FU with high-dose LV (Roswell Park Memorial Institute Regimen: RPMI) is the most commonly used regimen in Japan. The objectives of this study were to determine the recommended dose (RD) of RPMI combined with oxaliplatin and to evaluate the toxicity and efficacy at the RD. METHODS: The subjects were 18 patients with metastatic colorectal cancer. Oxaliplatin (85 mg/m2) was given intravenously over 2 h on days 1 and 15 with l-LV (250 mg/m2) given intravenously over 2 h and 5-FU as an intravenous bolus on days 1, 8, and 15. This treatment was repeated every 4 weeks. The dose of 5-FU was escalated from 400 mg/m2 (level 1) to 500 mg/m2 (level 2). RESULTS: A total of 14 patients received level 1, and 4 received level 2. Three of the patients had dose-limiting toxicity (DLT) in cycle 1 of level 2 (grade 3 thrombocytopenia, grade 4 neutropenia and grade 2 neutropenia in one patient each), requiring that treatment was delayed for longer than 7 days. None of the 14 patients given level 1 had DLT or grade 3 or 4 gastrointestinal toxicity. Sensory neuropathy occurred in all patients. Objective response rates were 61% in the 18 patients studied and 64% at level 1. The median time to progression was 171 days, and the median overall survival time was 603 days in the 18 patients studied. CONCLUSIONS: Oxaliplatin (85 mg/m2) with weekly bolus 5-FU (400 mg/m2) and high-dose l-LV (250 mg/m2) is recommended for further phase III studies in patients with metastatic colorectal cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias Retais/tratamento farmacológico , Adulto , Idoso , Anorexia/induzido quimicamente , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias do Colo/mortalidade , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Fluoruracila/administração & dosagem , Humanos , Leucovorina/administração & dosagem , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Neutropenia/induzido quimicamente , Compostos Organoplatínicos/administração & dosagem , Oxaliplatina , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Neoplasias Retais/mortalidade , Indução de Remissão , Taxa de Sobrevida
10.
Drug Metab Pharmacokinet ; 19(3): 216-26, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15499189

RESUMO

Regioselective sulfation of the phytoestrogens daidzein (DZ, 7,4'-dihydroxyisoflavone) and genistein (GS, 5,7,4'-trihydroxyisoflavone) was investigated using human liver cytosol and purified recombinant human sulfotransferase (SULT) isoforms, SULT1A1, SULT1A3, SULT2A1, and SULT1E1. 7-Position-preferential sulfation of DZ and GS was observed in human hepatic cytosols from 3 male and 3 female subjects. Average ratios for 7- to 4'-sulfate formation were 4.5:1 from DZ and 8.4:1 from GS in these human liver cytosols. Apparent K(m) values for the 7- and 4'-sulfation of DZ and GS by these cytosols were similar and in a range from 0.46 to 0.66 microM. All recombinant human SULTs had activity for 7- and 4'-sulfation of these phytoestrogens except for 7-sulfating activity of SULT1A3. SULT1A1 and SULT1E1 exhibited much higher catalytic efficiency, k(cat)/K(m), for 7- and 4'-sulfation of these substrates than did the other two, SULT1A3 and SULT2A1. SULT1A1 showed K(m) values of 0.47 and 0.52 microM for the mono-sulfation of DZ and GS, respectively, which were very similar to those of human cytosol. The observed k(cat)/K(m) indicated that SULT1A1 catalyzed 7-sulfation of DZ and GS at rates 4.4- and 8.8-fold higher, respectively, than such 4'-sulfation. However, with SULT1E1, catalytic efficiency was very similar for the sulfation of both positions. These data strongly suggest that SULT1A1 plays a major role in monosulfation of the phytoestrogens and determines the regioselectivity of sulfation in human hepatic cytosol. A kinetic study for 7,4'-disulfate formation of DZ and GS from their 7- and 4'-monosulfates indicated that SULT1E1 most efficiently catalyzed both reactions among human SULTs.


Assuntos
Genisteína/metabolismo , Isoflavonas/metabolismo , Fígado/enzimologia , Fitoestrógenos/metabolismo , Sulfotransferases/metabolismo , Adulto , Idoso , Arilsulfotransferase/metabolismo , Feminino , Genisteína/química , Humanos , Isoflavonas/química , Masculino , Pessoa de Meia-Idade , Fitoestrógenos/química , Estereoisomerismo , Sulfatos/metabolismo
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