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PURPOSE: To evaluate the efficacy of testosterone supplementation for improving aromatase inhibitor musculoskeletal symptoms (AIMSS). METHODS: Postmenopausal women experiencing moderate-to-severe arthralgias while taking adjuvant aromatase inhibitors for breast cancer were enrolled in this trial. Initially, patients were randomly allocated to receive either a subcutaneous testosterone pellet versus a placebo pellet. Due to slow accrual, the protocol was modified such that additional participants were randomized to receive either a topical testosterone gel or a placebo gel. Changes in patient-reported joint pain were compared between patients receiving testosterone and those receiving placebo using a two-sample t test. Changes in hot flashes and other vasomotor symptoms were also analyzed. Further analyses were conducted to evaluate whether 27 single nucleotide polymorphisms (SNPs) in 14 genes previously associated with AIMSS were associated with testosterone supplementation benefit. RESULTS: While 64% of patients reported an improvement in joint pain at 3 months, there were no significant differences in average pain or joint stiffness at 3 or 6 months between testosterone and placebo arms. Patients receiving testosterone did report improvements in strength, lack of energy, urinary frequency, and stress incontinence (p < 0.05). The subset of patients receiving subcutaneous testosterone also experienced improvements in hot flashes and mood swings. An inherited variant (rs7984870 CC genotype) in TNFSF11 was more likely to be associated with improvements in hot flashes in patients receiving testosterone. CONCLUSION: The doses of testosterone supplementation used in this study did not significantly improve AIMSS. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01573442.
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Inibidores da Aromatase/efeitos adversos , Artralgia/tratamento farmacológico , Fogachos/tratamento farmacológico , Dor Musculoesquelética/tratamento farmacológico , Testosterona/uso terapêutico , Administração Tópica , Artralgia/induzido quimicamente , Neoplasias da Mama/tratamento farmacológico , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Dor Musculoesquelética/induzido quimicamente , Polimorfismo de Nucleotídeo Único/genética , Pós-Menopausa , Qualidade de Vida/psicologia , Ligante RANK/genética , Testosterona/administração & dosagem , Resultado do TratamentoRESUMO
Vascular endothelial growth factor (VEGF) stimulates angiogenesis. Human hepatocellular carcinoma (HCC) is a VEGF-driven tumor often associated with chronic hepatitis B or C virus infection. The woodchuck is a well-characterized model of hepatitis B virus related HCC and a valuable tool for translational studies of novel VEGF targeted agents. We cloned the cDNA encoding woodchuck VEGF (wVEGF), transiently expressed it in COS cells and functionally characterized the recombinant protein. The open reading frame of wVEGF contained 645 nucleotides encoding a protein of 214 amino acids. Two protein bands (17 and 25â¯kDa) were detected in conditioned media of wVEGF expressing COS-1â¯cells and a single band of 25â¯kDa was identified in cell lysates. Addition of recombinant wVEGF to COS cells enhanced cell proliferation and stimulated VEGFR2, Akt, ERK1/2, and FAK phosphorylation. Sunitinib, a tyrosine kinase inhibitor, inhibited wVEGF- induced VEGFR2 phosphorylation in a dose-dependent manner. Finally, development of HCC in woodchucks was accompanied by increased laminin and PECAM1 expressing vessels, VEGFR2 expression, increased ligation of VEGF to VEGFR2, and a decrease in collagen IV-positive blood vessels. Our results suggest that woodchuck model can be used further to study angiogenesis and the effect of VEGF directed therapies in human HCC.
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Carcinoma Hepatocelular , Neoplasias Hepáticas Experimentais , Marmota , Proteínas de Neoplasias , Neovascularização Patológica , Fator A de Crescimento do Endotélio Vascular , Animais , Células COS , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Chlorocebus aethiops , Humanos , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Marmota/genética , Marmota/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
BACKGROUND: Several studies have suggested that low 25(OH) vitamin D3 levels may be prognostic in some malignancies, but no studies have evaluated their impact on treatment outcome in patients with acute myeloid leukemia (AML). METHODS: Vitamin D levels were evaluated in 97 consecutive, newly diagnosed, intensively treated patients with AML. MicroRNA expression profiles and single nucleotide polymorphisms (SNPs) in the 25(OH) vitamin D3 pathway genes were evaluated and correlated with 25(OH) vitamin D3 levels and treatment outcome. RESULTS: Thirty-four patients (35%) had normal 25(OH) vitamin D3 levels (32-100 ng/mL), 34 patients (35%) had insufficient levels (20-31.9 ng/mL), and 29 patients (30%) had deficient levels (<20 ng/mL). Insufficient/deficient 25(OH) vitamin D3 levels were associated with worse relapse-free survival (RFS) compared with normal vitamin D3 levels. In multivariate analyses, deficient 25(OH) vitamin D3 , smoking, European Leukemia Network genetic group, and white blood cell count retained their statistical significance for RFS. Several microRNAs and SNPs were associated with 25(OH) vitamin D3 levels, although none remained significant after multiple test corrections; one 25(OH) vitamin D3 receptor SNP, rs10783219, was associated with a lower complete remission rate (P = .0442) and with shorter RFS (P = .0058) and overall survival (P = .0011). CONCLUSIONS: It remains to be determined what role microRNA and SNP profiles play in contributing to low 25(OH) vitamin D3 level and/or outcome and whether supplementation will improve outcomes for patients with AML.
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Calcifediol/sangue , Colecalciferol/sangue , Regulação Neoplásica da Expressão Gênica , Leucemia Mieloide Aguda/sangue , MicroRNAs/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/patologia , Polimorfismo de Nucleotídeo Único/genética , Prognóstico , Receptores de Calcitriol/genética , Transcriptoma , Resultado do TratamentoRESUMO
The canonical mechanism behind tamoxifen's therapeutic effect on estrogen receptor α/ESR1+ breast cancers is inhibition of ESR1-dependent estrogen signaling. Although ESR1+ tumors expressing wild-type p53 were reported to be more responsive to tamoxifen (Tam) therapy, p53 has not been factored into choice of this therapy and the mechanism underlying the role of p53 in Tam response remains unclear. In a window-of-opportunity trial on patients with newly diagnosed stage I-III ESR1+/HER2/wild-type p53 breast cancer who were randomized to arms with or without Tam prior to surgery, we reveal that the ESR1-p53 interaction in tumors was inhibited by Tam. This resulted in functional reactivation of p53 leading to transcriptional reprogramming that favors tumor-suppressive signaling, as well as downregulation of oncogenic pathways. These findings illustrating the convergence of ESR1 and p53 signaling during Tam therapy enrich mechanistic understanding of the impact of p53 on the response to Tam therapy.
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Although some studies have reported associations between serum vitamin D level and prognosis in several cancers, others have found associations between genetic sequence variants (GSVs) in the vitamin D metabolism pathway genes and outcomes in various cancers including head and neck cancer (HNC). We comprehensively evaluated the association and interaction of GSVs in vitamin D metabolism pathway genes and their regulatory effects on circulatory serum vitamin D level in HNC outcome. We systemically evaluated the association of 89 tagging and candidate-based GSVs in six major vitamin D metabolism pathway genes (VDR, GC, CYP24A1, CYP27A1, CYP27B1 and CYP2R1) and the circulating serum vitamin D level with overall survival (OS) and second primary cancer (SPC) in 522 Stages I-II radiation-treated patients with HNC. For OS: median follow-up time was 8 years; for SPC, 4.4 years. The most common subsite was the larynx (84%). Three hundred and twelve patients were alive at the end of follow-up for OS. SPCs were diagnosed in 108 patients and were primarily of lung (46%). Serum vitamin D levels were significantly lower in patients carrying the minor alleles of GC:rs4588 and CYP2R1:rs10500804. CYP24A1:rs2296241 was significantly associated with OS and CYP2R1:rs1993116 was with SPC. These two GSVs remained significantly associated after adjusting for serum vitamin D level and important clinical factors. GSVs in the vitamin D metabolism pathway genes were associated with disease outcomes in HNC patients; however, these GSVs are different from those affecting serum vitamin D levels.
Assuntos
Biomarcadores Tumorais/genética , Sistema Enzimático do Citocromo P-450/genética , Neoplasias de Cabeça e Pescoço/genética , Segunda Neoplasia Primária/genética , Polimorfismo de Nucleotídeo Único/genética , Vitamina D/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/sangue , DNA de Neoplasias/genética , Feminino , Seguimentos , Predisposição Genética para Doença , Genótipo , Neoplasias de Cabeça e Pescoço/sangue , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Segunda Neoplasia Primária/sangue , Segunda Neoplasia Primária/mortalidade , Segunda Neoplasia Primária/radioterapia , Reação em Cadeia da Polimerase , Prognóstico , Receptores de Calcitriol/genética , Fatores de Risco , Taxa de SobrevidaRESUMO
OBJECTIVE: ABT-751, a novel orally available antitubulin agent, is mainly eliminated as inactive glucuronide (ABT-751G) and sulfate (ABT-751S) conjugates. We performed a pharmacogenetic investigation of ABT-751 pharmacokinetics using in-vitro data to guide the selection of genes for genotyping in a phase I trial of ABT-751. METHODS: UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes were screened for ABT-751 metabolite formation in vitro. Forty-seven cancer patients treated with ABT-751 were genotyped for 21 variants in these genes. RESULTS: UGT1A1, UGT1A4, UGT1A8, UGT2B7, and SULT1A1 were found to be involved in the formation of inactive ABT-751 glucuronide (ABT-751G) and sulfate (ABT-751S). SULT1A1 copy number (>2) was associated with an average 34% increase in ABT-751 clearance (P=0.044), an 18% reduction in ABT-751 AUC (P=0.045), and a 50% increase in sulfation metabolic ratios (P=0.025). UGT1A8 rs6431558 was associated with a 28% increase in glucuronidation metabolic ratios (P=0.022), and UGT1A4*2 was associated with a 65% decrease in ABT-751 C trough (P=0.009). CONCLUSION: These results might represent the first example of a clinical pharmacokinetic effect of the SULT1A1 copy number variant on the clearance of a SULT1A1 substrate. A-priori selection of candidate genes guided by in-vitro metabolic screening enhanced our ability to identify genetic determinants of interpatient pharmacokinetic variability.
Assuntos
Antineoplásicos/farmacocinética , Sulfonamidas/farmacocinética , Moduladores de Tubulina/farmacocinética , Adulto , Idoso , Arilsulfotransferase/genética , Feminino , Dosagem de Genes , Variação Genética , Glucuronosiltransferase/genética , Glucuronosiltransferase/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Sulfotransferases/genética , Sulfotransferases/metabolismoRESUMO
Low pretreatment vitamin D status has been associated with worsened disease outcomes in patients with cancer at various sites. Its prognostic significance in head and neck cancer (HNC) patients has not been studied. Patients with HNC who participated in a randomized trial were evaluated for: (i) total intake of vitamin D from diet and supplements using a validated food frequency questionnaire (all trial participants, n = 540) and (ii) pretreatment serum 25-hydroxyvitamin D through a radioimmunoassay (n = 522). The association of dietary/serum measures of vitamin D status with HNC recurrence, second primary cancer (SPC) incidence, and overall mortality was evaluated using multivariate Cox proportional hazard models. There was no significant association between dietary or serum vitamin D measures and the three HNC outcomes. The hazard ratios (HRs) comparing the highest with the lowest quartile of dietary/supplemental vitamin D intake were 1.10 (95% confidence interval (CI): 0.66-1.84) for recurrence, 1.05 (95% CI: 0.63-1.74) for SPC, and 1.27 (95% CI: 0.87-1.84) for overall mortality. HRs comparing the uppermost to the lowest quartile of serum 25-hydroxyvitamin D levels were 1.12 (95% CI: 0.65-1.93) for recurrence, 0.72 (95% CI: 0.40-1.30) for SPC, and 0.85 (95% CI: 0.57-1.28) for overall mortality. There was no effect modification by cancer stage, season of initial treatment, or trial arm. Among patients with HNC, vitamin D status before treatment does not influence disease outcomes. Our results contrast with those from most published studies, which suggest prognostic significance of vitamin D status in cancer patients at least in subgroups.
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Suplementos Nutricionais , Neoplasias de Cabeça e Pescoço/sangue , Vitamina D/análogos & derivados , Idoso , Dieta , Feminino , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Radioterapia/métodos , Recidiva , Inquéritos e Questionários , Resultado do Tratamento , Vitamina D/sangueRESUMO
Health-related quality of life (HRQOL) is an important prognostic patient-reported outcome in oncology. Because prior studies suggest that HRQOL is, in part, heritable, we performed a GWAS to elucidate genetic factors associated with HRQOL in breast cancer survivors. Physical and mental HRQOL were measured via paper surveys that included the PROMIS-10 physical and mental health domain scales in 1442 breast cancer survivors participating in the Mayo Clinic Breast Disease Registry (MCBDR). In multivariable regression analyses, age and financial concerns were significantly associated with global physical health (age: p = 1.6 × 10-23; financial concerns: p = 4.8 × 10-40) and mental health (age: p = 3.5 × 10-7; financial concerns: p = 2.0 × 10-69). Chemotherapy was associated with worse global mental health (p = 0.01). In the GWAS, none of the SNPs reached the genome-wide association significance threshold of 5 × 10-8 for associations with either global physical or global mental health, however, a cluster of SNPs in SCN10A, particularly rs112718371, appeared to be linked to worse global physical health (p = 5.21 × 10-8). Additionally, SNPs in LMX1B, SGCD, PARP12 and SEMA5A were also moderately associated with worse physical and mental health (p < 10-6). These biologically plausible candidate SNPs warrant further study as possible predictors of HRQOL.
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Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially permanent adverse effect of chemotherapeutic agents including taxanes such as paclitaxel and platinum-based compounds such as oxaliplatin and carboplatin. Previous studies have suggested that genetics may impact the risk of CIPN. We conducted genome-wide association studies (GWASs) for CIPN in two independent populations who had completed European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-CIPN20 assessments (a CIPN-specific 20-item questionnaire which includes three scales that evaluate sensory, autonomic, and motor symptoms). The study population N08Cx included 692 participants from three clinical trials (North Central Cancer Treatment Group (NCCTG) N08C1, N08CA, and N08CB) who had been treated with paclitaxel, paclitaxel plus carboplatin, or oxaliplatin. The primary endpoint for the GWAS was the change from pre-chemotherapy CIPN20 sensory score to the worse score over the following 18 weeks. Study population The Mayo Clinic Breast Disease Registry (MCBDR) consisted of 381 Mayo Clinic Breast Disease Registry enrollees who had been treated with taxane or platinum-based chemotherapy. The primary endpoint for the GWAS assessed was the earliest CIPN20 sensory score available after the completion of chemotherapy. In multivariate model analyses, chemotherapy regimen (p = 3.0 × 10-8) and genetic ancestry (p = 0.007) were significantly associated with CIPN in the N08Cx population. Only age (p = 0.0004) was significantly associated with CIPN in the MCBDR population. The SNP most associated with CIPN was rs56360211 near PDE6C (p =7.92 × 10-8) in N08Cx and rs113807868 near TMEM150C in the MCBDR (p = 1.27 × 10-8). Due to a lack of replication, we cannot conclude that we identified any genetic predictors of CIPN.
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The purpose of our study was to evaluate the efficacy of a combination of pralatrexate plus oxaliplatin in advanced esophagogastric cancer (EGC), analyze the impact of polymorphisms in folate metabolism pathway genes on toxicity and efficacy of pralatrexate, and to evaluate microRNA profile of tumor epithelium as a predictive biomarker. This was a two-stage trial with a safety lead in cohort and a primary endpoint of overall response rate (ORR). Patients received biweekly intravenous oxaliplatin (85 mg/m2) and pralatrexate (Dose level 1 [D1], 120 mg/m2; dose level-1 [D-1] 100 mg/m2). Single-nucleotide polymorphisms (SNP) in genes encoding proteins involved in pralatrexate metabolism were evaluated in germline DNA. microRNA profiling of the tumor epithelium was performed. ORR was 26%. Dose-limiting toxicities were observed in 2 of 4 patients at D1 and none at D-1. The T>C polymorphism in DHFR rs11951910 was significantly associated with lower progression-free survival (PFS; P ≤ 0.01), whereas the presence of the SLC19A1 rs2838957 G>A polymorphism was associated with improved PFS (P = 0.02). Presence of the GGH rs3780130 A>T and SLC19A1 rs1051266 G>A polymorphisms were significantly associated with better overall survival (OS; P = 0.01), whereas GGH rs7010484 T>C polymorphism was associated significantly with reduced OS (P = 0.04). There was no correlation between epithelial microRNA expression profile with disease progression or response. We conclude that the combination of oxaliplatin and pralatrexate is safe, is well tolerated, and has modest efficacy in advanced EGC. Pharmacogenomic analysis may be relevant to the use of pralatrexate in combination with platinum agents.
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Aminopterina/análogos & derivados , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Esofágicas/tratamento farmacológico , Oxaliplatina/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Aminopterina/farmacologia , Aminopterina/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Feminino , Humanos , Masculino , Oxaliplatina/farmacologiaRESUMO
Folylpolyglutamate synthase (FPGS) catalyzes the polyglutamation of folic acid, methotrexate, and pemetrexed to produce highly active metabolites. To characterize genetic variation in the FPGS gene, FPGS, have resequenced the gene in four different ethnic populations. Thirty-four single nucleotide polymorphisms were identified including five nonsynonymous coding single nucleotide polymorphisms that altered the FPGS protein sequence: F13L and V22I polymorphisms in the mitochondrial isoform of FPGS, and R466/424C, A489/447V, and S499/457F polymorphisms, which exist in both the mitochondrial and cytosolic isoforms. When expressed in AuxB1 cells, the A447V cytosolic variant was functionally similar to the wild-type cytosolic (WT Cyt) allozyme, whereas the R424C and S457F cytosolic variants were reduced by approximately 2-fold in protein expression compared with WT Cyt (P < 0.01). The intrinsic clearance of glutamate was reduced by 12.3-fold (R424C, P < 0.01) and 6.2-fold (S457F, P < 0.01), whereas the intrinsic clearance of methotrexate was reduced by 4.2-fold (R424C, P < 0.05) and 5.4-fold (S457F, P < 0.05) in these two cytosolic variants when compared with the WT Cyt isoform. Additionally, the in vitro enzyme velocity at saturating pemetrexed concentrations was reduced by 1.6-fold (R424C, P < 0.05) and 2.6-fold (S457F, P < 0.01) compared with WT Cyt. AuxB1 cells harboring these same cytosolic variant allozymes displayed significant increases in the EC(50) for folic acid and in the IC(50) values for both methotrexate and pemetrexed relative to the WT Cyt form of FPGS. These observations suggest that genetic variations in FPGS may alter the efficacy of antifolate therapy in cancer patients.
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Peptídeo Sintases/genética , Sequência de Bases , Citosol/enzimologia , Éxons , Ácido Fólico/farmacocinética , Ácido Fólico/farmacologia , Antagonistas do Ácido Fólico/farmacocinética , Antagonistas do Ácido Fólico/farmacologia , Variação Genética , Glutamatos/farmacocinética , Glutamatos/farmacologia , Guanina/análogos & derivados , Guanina/farmacocinética , Guanina/farmacologia , Haplótipos , Humanos , Cinética , Metotrexato/farmacocinética , Metotrexato/farmacologia , Pemetrexede , Peptídeo Sintases/biossíntese , Peptídeo Sintases/metabolismo , Polimorfismo de Nucleotídeo Único , Especificidade por SubstratoRESUMO
Thiopurine S-methyltransferase (TPMT) modulates the cytotoxic effects of thiopurine prodrugs such as 6-mercaptopurine by methylating them in a reaction using S-adenosyl- l-methionine as the donor. Patients with TPMT variant allozymes exhibit diminished levels of protein and/or enzyme activity and are at risk for thiopurine drug-induced toxicity. We have determined two crystal structures of murine TPMT, as a binary complex with the product S-adenosyl- l-homocysteine and as a ternary complex with S-adenosyl- l-homocysteine and the substrate 6-mercaptopurine, to 1.8 and 2.0 A resolution, respectively. Comparison of the structures reveals that an active site loop becomes ordered upon 6-mercaptopurine binding. The positions of the two ligands are consistent with the expected S N2 reaction mechanism. Arg147 and Arg221, the only polar amino acids near 6-mercaptopurine, are highlighted as possible participants in substrate deprotonation. To probe whether these residues are important for catalysis, point mutants were prepared in the human enzyme. Substitution of Arg152 (Arg147 in murine TPMT) with glutamic acid decreases V max and increases K m for 6-mercaptopurine but not K m for S-adenosyl- l-methionine. Substitution at this position with alanine or histidine and similar substitutions of Arg226 (Arg221 in murine TPMT) result in no effect on enzyme activity. The double mutant Arg152Ala/Arg226Ala exhibits a decreased V max and increased K m for 6-mercaptopurine. These observations suggest that either Arg152 or Arg226 may participate in some fashion in the TPMT reaction, with one residue compensating when the other is altered, and that Arg152 may interact with substrate more directly than Arg226, consistent with observations in the murine TPMT crystal structure.
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Metiltransferases/química , Metiltransferases/genética , Substituição de Aminoácidos , Animais , Arginina , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Variação Genética , Humanos , Cinética , Metiltransferases/isolamento & purificação , Metiltransferases/metabolismo , Camundongos , Modelos Moleculares , Conformação Proteica , Mapeamento por Restrição , Especificidade por SubstratoRESUMO
The purpose of this study was to investigate the sulfation of resveratrol (3,5,4'-trihydroxystilbene) and its potential to exhibit drug-drug interactions via sulfation. The possible interaction of resveratrol with 17beta-estradiol (E2), a major estrogen hormone and prototypic substrate for sulfate conjugation, was studied. Resveratrol and E2 are both known to undergo sulfate conjugation catalyzed by human sulfotransferases (SULTs). Resveratrol is a phytoestrogen with mixed estrogen agonist/antagonist properties that is being developed as a chemopreventive agent. The sulfate conjugation of E2 and resveratrol were studied individually using S9 fractions from human liver and jejunum as well as recombinant human SULT isoforms. The sulfation of E2 (3-20 nM) was then investigated in the presence of various concentrations (0, 0.5, 1, and 2 microM) of resveratrol using the two S9 preparations as well as recombinant SULT1E1, the major isoform responsible for E2 sulfation. Resveratrol inhibited E2 sulfation with estimated K(i) values of 1.1 microM (liver), 0.6 microM (jejunum), and 2.3 microM (SULT1E1), concentrations that could be pharmacologically relevant. The results suggest that these phytoestrogens can potentially alter the homeostasis of estrogen levels. These findings also imply that resveratrol may inhibit the metabolism of other estrogen analogs or therapeutic agents such as ethinylestradiol or dietary components that are also substrates for SULT1E1.
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Estradiol/metabolismo , Jejuno/metabolismo , Fígado/metabolismo , Microssomos/metabolismo , Fitoestrógenos/farmacologia , Estilbenos/farmacologia , Sulfotransferases/metabolismo , Arilsulfotransferase/metabolismo , Feminino , Humanos , Jejuno/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Microssomos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Proteínas Recombinantes/metabolismo , Resveratrol , Sulfatos/metabolismoRESUMO
BACKGROUND: Acetaminophen (APAP) use in early pregnancy has been associated with the risk of gastroschisis, a rare but serious congenital defect of the abdominal wall. The purpose of this study was to characterize the variability of APAP sulfation in a panel of human fetal livers and to identify the sulfotransferases (SULT) isoform(s) responsible for catalyzing that activity. METHODS: APAP sulfation was determined in a panel of human fetal (n = 73) and postnatal (n = 18) liver cytosol preparations and correlated with the catalytic activity of various SULT isoforms as determined using prototypic substrates and specific antibodies. RESULTS: Of 10 heterologously expressed SULT isoforms examined, SULT1A1, SULT1A3/4, SULT1E1, and SULT2A1 all catalyzed the formation of APAP sulfate with K(m) values of 2.4, 1.5, 1.9, and 3.7 mM, respectively. Catalytic activities for these four isoforms were expressed at varying levels in human fetal liver, and APAP sulfation was positively correlated with each of the four prototypic activities. Several regression and clustering approaches revealed that SULT1A3/4 was the primary determinant of prenatal APAP sulfation but that SULT1A1 or SULT1E1 were also major contributors in subsets of samples. CONCLUSIONS: The results of this study lead to the hypothesis that genetic variation in SULT1A3/4 represents a risk factor for the development of gastroschisis in the offspring of mothers exposed to APAP early in pregnancy. Interpretation of genetic association studies conducted to test this hypothesis will be complicated by the variable contributions of other SULTs toward APAP-sulfate formation in individual subjects.
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Anormalidades Induzidas por Medicamentos , Acetaminofen/metabolismo , Fígado/embriologia , Farmacogenética , Sulfatos/metabolismo , Humanos , Fígado/metabolismo , Sulfotransferases/genética , Sulfotransferases/metabolismoRESUMO
Aromatase [cytochrome P450 19 (CYP19)] is a critical enzyme for estrogen biosynthesis, and aromatase inhibitors are of increasing importance in the treatment of breast cancer. We set out to identify and characterize genetic polymorphisms in the aromatase gene, CYP19, as a step toward pharmacogenomic studies of aromatase inhibitors. Specifically, we "resequenced" all coding exons, all upstream untranslated exons plus their presumed core promoter regions, all exon-intron splice junctions, and a portion of the 3'-untranslated region of CYP19 using 240 DNA samples from four ethnic groups. Eighty-eight polymorphisms were identified, resulting in 44 haplotypes. Functional genomic studies were done with the four nonsynonymous coding single nucleotide polymorphisms (cSNP) that we observed, two of which were novel. Those cSNPs altered the following amino acids: Trp39Arg, Thr201Met, Arg264Cys, and Met364Thr. The Cys264, Thr364, and double variant Arg39Cys264 allozymes showed significant decreases in levels of activity and immunoreactive protein when compared with the wild-type (WT) enzyme after transient expression in COS-1 cells. A slight decrease in protein level was also observed for the Arg39 allozyme, whereas Met201 displayed no significant changes in either activity or protein level when compared with the WT enzyme. There was also a 4-fold increase in apparent K(m) value for Thr364 with androstenedione as substrate. Of the recombinant allozymes, only the double mutant (Arg39Cys264) displayed a significant change from the WT enzyme in inhibitor constant for the aromatase inhibitors exemestane and letrozole. These observations indicate that genetic variation in CYP19 might contribute to variation in the pathophysiology of estrogen-dependent disease.
Assuntos
Aromatase/genética , Aromatase/metabolismo , Alelos , Animais , Inibidores da Aromatase/metabolismo , Inibidores da Aromatase/farmacologia , Western Blotting , Células COS , Chlorocebus aethiops , DNA/genética , Genômica , Haplótipos , Humanos , Cinética , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Frações Subcelulares/metabolismoRESUMO
PURPOSE: We determined the maximum-tolerated dose (MTD) and the dose-limiting toxicities (DLT) of 17-allylamino-17-demethoxygeldanamycin (17-AAG) when infused on days 1, 8, and 15 of a 28-day cycle in advanced solid tumor patients. We also characterized the pharmacokinetics of 17-AAG, its effect on chaperone and client proteins, and whether cytochrome P450 (CYP) 3A5 and NAD(P)H:quinone oxidoreductase 1 (NQO1) polymorphisms affected 17-AAG disposition or toxicity. PATIENTS AND METHODS: An accelerated titration design was used. Biomarkers were measured in peripheral-blood mononuclear cells (PBMCs) at baseline and on days 1 and 15, and pharmacokinetic analysis was performed on day 1 of cycle 1. CYP3A5*3 and NQO1*2 genotypes were determined and correlated with pharmacokinetics and toxicity. RESULTS: Twenty-one patients received 52 courses at 11 dose levels. DLTs at 431 mg/m(2) were grade 3 bilirubin (n = 1), AST (n = 1), anemia (n = 1), nausea (n = 1), vomiting (n = 1), and myalgias (n = 1). No tumor responses were seen. 17-AAG consistently increased heat shock protein (Hsp) 70 levels in PBMCs. At the MTD, the clearance and half-life (t(1/2)) of 17-AAG were 11.6 L/h/m(2) and 4.15 hours, respectively; whereas the active metabolite 17-aminogeldanamycin had a t(1/2) of 7.63 hours. The CYP3A5*3 and NQO1*2 polymorphisms were not associated with 17-AAG toxicity. The CYP3A5*3 polymorphism was associated with higher 17-AAG clearance. CONCLUSION: The MTD of weekly 17-AAG is 308 mg/m(2). 17-AAG induced Hsp70 in PBMCs, indicating that Hsp90 has been affected. Further evaluation of 17-AAG is ongoing using a twice-weekly regimen, and this schedule of 17-AAG is being tested in combination with chemotherapy.
Assuntos
Neoplasias/tratamento farmacológico , Rifabutina/análogos & derivados , Rifabutina/administração & dosagem , Rifabutina/efeitos adversos , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Benzoquinonas , Biomarcadores/análise , Citocromo P-450 CYP3A , Sistema Enzimático do Citocromo P-450/genética , Esquema de Medicação , Feminino , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Lactamas Macrocíclicas , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , NAD(P)H Desidrogenase (Quinona)/genética , Polimorfismo GenéticoRESUMO
Recent experimental evidence has shown that catechol estrogens can be activated through metabolism to form depurinating DNA adducts and thereby initiate cancer. Limited data are available regarding this pathway in epithelial ovarian cancer. We conducted a case-control study of 503 incident epithelial ovarian cancer cases at the Mayo Clinic in Rochester, MN, and Jacksonville, FL, and a 48-county region in North Carolina. Six hundred nine cancer-free controls were frequency matched to the cases on age, race, and residence. After an interview to obtain data on risk factors, a sample of blood was collected for DNA isolation. Subjects were genotyped for seven common single nucleotide polymorphisms in four genes involved in catechol estrogen formation (CYP1A1 and CYP1B1) or conjugation (COMT and SULT1A1). Data were analyzed using logistic regression, stratified by race, and with adjustment for design factors and potential confounders. None of the individual genotypes were significantly associated with ovarian cancer risk. However, an oligogenic model that considered the joint effects of the four candidate genes provided evidence for an association between combinations of these genes and ovarian cancer status (P = 0.015). Although preliminary, this study provides some support for the hypothesis that low-penetrance susceptibility alleles may influence risk of epithelial ovarian cancer.
Assuntos
Carcinoma/etiologia , Carcinoma/genética , Estrogênios/metabolismo , Neoplasias Ovarianas/etiologia , Neoplasias Ovarianas/genética , Polimorfismo Genético , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
1. Estrogens are used as drugs and estrogen exposure is a risk factor for hormone-dependent diseases such as breast cancer. Sulfate conjugation is an important pathway for estrogen metabolism. The sulfotransferase (SULT) enzyme SULT1E1 has the lowest K(m) values for estrogens and catecholestrogens of the 10 known human SULT isoforms. 2. We previously cloned and characterized the human SULT1E1 cDNA and gene as steps toward pharmacogenetic studies. In the present experiments, we set out to determine whether common, functionally significant genetic polymorphisms might exist for SULT1E1. As a first step, we 'resequenced' the eight SULT1E1 exons and exon-intron splice junctions as well as portions of the 5'-flanking region using DNA from 60 African-American and 60 Caucasian-American subjects. 3. In all, 23 polymorphisms, 22 single nucleotide polymorphisms (SNPs) and one insertion deletion were observed. There were three nonsynonymous coding SNPs (cSNPs) that altered the following encoded amino acids: Asp22Tyr, Ala32Val and Pro253His. Among these, 12 pairs of SNPs were tightly linked. In addition, 12 unambiguous SULT1E1 haplotypes were identified, including six that were common to both populations studied. 4. Transient expression in COS-1 cells of constructs containing the three nonsynonymous cSNPs showed significant decreases in SULT1E1 activity for the Tyr22 and Val32 allozymes, with corresponding decreases in levels of immunoreactive protein. There were no changes in levels of either activity or immunoreactive protein for the His253 allozyme. Apparent K(m) values of the Val32 allozyme for the two cosubstrates for the reaction, 17beta-estradiol and 3'-phosphoadenosine 5'-phosphosulfate, were not significantly different from those of the wild-type enzyme, but there was a two- to three-fold increase in K(m) values for the His253 allozyme and a greater than five-fold increase for the Tyr22 allozyme. 5. These observations raise the possibility that genetically determined variation in SULT1E1-catalyzed estrogen sulfation might contribute to the pathophysiology of estrogen-dependent diseases as well as variation in the biotransformation of exogenously administered estrogens.
Assuntos
Negro ou Afro-Americano/genética , DNA/análise , Farmacogenética , Polimorfismo de Nucleotídeo Único , Sulfotransferases/genética , População Branca/genética , Animais , Western Blotting , Células COS , Chlorocebus aethiops , Cristalografia por Raios X , Estabilidade Enzimática , Frequência do Gene/genética , Ligação Genética/genética , Haplótipos/genética , Humanos , Isoenzimas/química , Isoenzimas/genética , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Análise de Sequência de DNA , Sulfotransferases/química , TransfecçãoRESUMO
BACKGROUND: We hypothesized that the combination of bevacizumab, carboplatin, and pemetrexed will be an effective first-line regimen in fit, elderly patients with nonsquamous non-small-cell lung cancer. METHODS: Treatment-naïve, stage IIIB/IV nonsquamous non-small-cell lung cancer patients more than 70 years old with good performance status (Eastern Cooperative Oncology Group performance status 0-1) and adequate organ function were eligible. Carboplatin area under the curve 6, pemetrexed 500 mg/m, and bevacizumab 15 mg/kg were administered on day 1 of each 21-day cycle (up to six cycles) followed by maintenance pemetrexed and bevacizumab. The primary end point of 6-month progression-free survival rate of at least 70% was assessed using a one-stage binomial design. Quality of life (QOL) questionnaires were administered. Polymorphisms in genes encoding relevant proteins (drug targets, transport, and metabolism proteins) were correlated with treatment outcome. RESULTS: Fifty-seven eligible patients were enrolled. Median age was 74.5 years. Median treatment cycles received was 6. The most common grade 3 or higher non-hematologic adverse events were fatigue (26%) and hypertension (11%); 16% had grade 4 neutropenia and 6.5% had grade 4 thrombocytopenia. Three patients experienced grade 3/4 hemorrhagic events (one pulmonary, two gastrointestinal). Primary end point of PFS6 was 60% (95% confidence interval [CI]: 45.9-73%). Median PFS was 7.0 months (95% CI: 5.9-10.1), median overall survival was 13.7 months (95% CI: 9.4-16.8). Polymorphic KDR and VEGFA variants correlated with survival and toxicity, respectively. There was no significant change in overall QOL scores over time. CONCLUSION: This regimen is feasible and did not decrease the QOL in this study population. However, it did not meet the primary efficacy end point.