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1.
Front Oncol ; 14: 1429221, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39484033

RESUMO

Introduction: Our monocentric and retrospective study aimed to investigate the clinical effectivity of HEPA filters in combination with the antifungal drug prophylaxis in patients with AML undergoing intensive chemotherapy and allogeneic stem cell transplantation (SCT). Methods/Results: We included 177 patients between 2005 and 2015 representing a total of 372 in-hospital stays, 179 in the HEPA cohort (+HEPA) and 193 in the cohort without HEPA filters (-HEPA). No significant additional benefit of HEPA filtration on the risk reduction of IFI was observed. HEPA filtration did not significantly affect the risk of intensive care unit (ICU) admissions or early mortality rates. In patients who received allogeneic SCT in first complete remission with antifungal drug prophylaxis during prior induction treatment, a numerical but not significant improvement in long-term overall survival was noted in the +HEPA cohort compared to the -HEPA cohort (55% to 66%, p = 0.396). For better depicting of the clinical reality, we determined the so-called clinical suspected IFI (csIFI) -defined as cases with antifungal treatment after recommended prophylaxis without fulfilling current EORTC criteria. Especially in patients with a high risk for second IFI, significant risk reduction of csIFI and frequency of ICU admissions was observed when voriconazole was used as secondary antifungal prophylaxis. (csIFI, adjusted effect: OR 0.41, 95% CI (0.21 - 0.82), p = 0.01; csIFI, subgroup-specific effect: OR 0.35, 95% CI (0.15 - 0.78), p = 0.01; ICU, adjusted effect: OR 0.44, 95 CI (0.19 - 1.01), p = 0.05; respectively). Discussion: In summary, the study suggests the efficacy of secondary antifungal prophylaxis in preventing IFI in AML patients undergoing intensive treatment. The addition of HEPA filtration also demonstrated additional numerous benefits in reducing the frequency of IFI-associated complications.

2.
Front Oncol ; 14: 1445427, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39391235

RESUMO

Tenosynovial giant cell tumor (TGCT) is a rare type of tumor that originates from the synovium of joints and tendon sheaths. It is characterized by recurring genetic abnormalities, often involving the CSF1 gene. Common symptoms include pain and swelling, which are not specific to TGCT, so MRI and a pathological biopsy are needed for an accurate diagnosis. We report the case of a 45-year-old man who experienced painful swelling in his right hip for six months. Initially, this was diagnosed as Erdheim-Chester disease. However, whole exome sequencing (WES) and RNA-Sequencing revealed a CSF1::GAPDHP64 fusion, leading to a revised diagnosis of TGCT. The patient was treated with pegylated interferon and imatinib, which resulted in stable disease after three months. Single-cell transcriptome analysis identified seven distinct cell clusters, revealing that neoplastic cells expressing CSF1 attract macrophages. Analysis of ligand-receptor interactions showed significant communication between neoplastic cells and macrophages mediated by CSF1 and CSF1R. Our findings emphasize the importance of comprehensive molecular analysis in diagnosing and treating rare malignancies like TGCT.

3.
Strahlenther Onkol ; 200(7): 583-594, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38381142

RESUMO

BACKGROUND AND OBJECTIVE: Data on enteral tube feeding in head and neck cancer (HNC) patients undergoing chemoradiotherapy vary considerably between German institutions. This survey aims to investigate the management of feeding tubes in an interdisciplinary context across Germany. MATERIALS AND METHODS: Between December 2022 and May 2023, 70 participants (42 radiation oncologists, 12 medical oncologists, 14 head and neck surgeons, and 2 physicians covering several specialties) responded to our web-based survey. In addition to the type of institution (university hospital, private practice, etc.), their age, and professional experience (in years), participants were asked several questions on the indication and institutional policy for tube placement and management (prophylactic/reactive nasogastric or gastrostomy tube). All questions were mandatory single- or multiple-choice questions, while additional comments were possible by email. RESULTS: Most participants were employed at a university hospital (n = 52; 74.3%) and came from a radiation oncology background (n = 42; 60%). Fifty-four contributors (77.1%) reported that no nutritional risk screening prior to chemoradiotherapy was routinely performed, and 71.4% (n = 50) stated that no standardized protocol was used at the institution to set the indication for tube placement. Generally, policies and methods of tube feeding vary considerably between the individual institutions and specialties. However, the majority (n = 56, 80%) recommended a prophylactic percutaneous enteral gastrostomy (PEG) tube to their patients before chemoradiotherapy. Still, there was no consistent trend regarding the approach for reactive tube feeding. CONCLUSION: The policies and methods of tube feeding vary considerably between the individual institutions and specialties in Germany. In the era of individualized medicine, uniform protocols are difficult to establish. However, a baseline nutritional risk screening could simplify decision-making in clinical practice.


Assuntos
Quimiorradioterapia , Nutrição Enteral , Gastrostomia , Neoplasias de Cabeça e Pescoço , Intubação Gastrointestinal , Humanos , Alemanha , Neoplasias de Cabeça e Pescoço/terapia , Masculino , Inquéritos e Questionários , Padrões de Prática Médica/estatística & dados numéricos , Feminino , Pesquisas sobre Atenção à Saúde , Comunicação Interdisciplinar , Pessoa de Meia-Idade , Radio-Oncologistas
4.
Ann Hematol ; 102(2): 323-328, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36576532

RESUMO

Relapse in patients with acute myeloid leukemia (AML) is common and is associated with a dismal prognosis. Treatment options are limited and the understanding of molecular response patterns is still challenging. We analyzed the clonal response patterns of 15 patients with relapsed/refractory AML treated with selinexor in a phase II trial (SAIL). DNA was analyzed at three time points and showed a decline of mutated alleles in FLT3, SF3B1, and TP53 under SAIL treatment. Overall survival (OS) was similar between patients with declining versus persisting clones. We show an interesting long-term course of a patient who relapsed after allogeneic stem cell transplantation (alloHCT) with SF3B1- and SRSF2-mutated AML and received selinexor as maintenance treatment for 4 years. Measurable residual disease (MRD) remained detectable for 2 weeks after donor lymphocyte infusion (DLI) in this patient and then remained negative under selinexor maintenance treatment. Selinexor was tolerated well and was stopped after 4 years of SAIL treatment. We present an exploratory study and identify subclonal patterns of patients treated with selinexor.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Prognóstico , Recidiva
5.
Cancers (Basel) ; 14(21)2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36358652

RESUMO

This non-interventional, prospective phase IV trial evaluated trabectedin in patients with soft tissue sarcoma (STS) in real-life clinical practice across Germany. The primary endpoints were progression-free survival (PFS) rates at 3 and 6 months, as defined by investigators. Overall, 128 patients from 19 German sites were evaluated for efficacy and 130 for safety. Median age was 58.5 years (range: 23-84) and leiomyosarcoma was the most frequent histotype (n = 45; 35.2%). Trabectedin was mostly used as second/third-line treatment (n = 91; 71.1%). Median PFS was 5.2 months (95% CI: 3.3-6.7), with 60.7% and 44.5% of patients free from progression at 3 and 6 months, respectively. Median overall survival was 15.2 months (95% CI: 9.6-21.4). One patient achieved a complete and 14 patients a partial response, conferring an objective response rate of 11.7%. Decreases in white blood cells (27.0% of patients), platelets (16.2%) and neutrophils (13.1%) and increased alanine aminotransferase (10.8%) were the most common trabectedin-related grade 3/4 adverse drug reactions. Two deaths due to pneumonia and sepsis were considered trabectedin-related. Trabectedin confers clinically meaningful activity in patients with multiple STS histotypes, comparable to that previously observed in clinical trials and other non-interventional studies, and with a manageable safety profile.

6.
Cancers (Basel) ; 13(6)2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33799576

RESUMO

We aimed to evaluate the efficacy and toxicity of paclitaxel combined with pazopanib in advanced angiosarcoma (AS). The primary end point was progression-free survival (PFS) rate at six months (PFSR6). Planned accrual was 44 patients in order to detect a PFSR6 of >55%, with an interim futility analysis of the first 14 patients. The study did not meet its predetermined interim target of 6/14 patients progression-free at 6 months. At the time of this finding, 26 patients had been enrolled between July 2014 and April 2016, resulting in an overrunning of 12 patients. After a median follow-up of 9.5 (IQR 7.7-15.4) months, PFSR6 amounted to 46%. Two patients had a complete and seven patients a partial response. Patients with superficial AS had a significantly higher PFSR6 (61% vs. 13%, p = 0.0247) and PFS (11.3 vs. 2.7 months, p < 0.0001) compared to patients with visceral AS. The median overall survival in the entire cohort was 21.6 months. A total of 10 drug-related serious adverse effects were reported in 5 patients, including a fatal hepatic failure. Although our study did not meet its primary endpoint, the median PFS of 11.6 months in patients with superficial AS appears to be promising. Taking recent reports into consideration, future studies should evaluate the safety and efficacy of VEGFR and immune checkpoint inhibitors with or without paclitaxel in a randomized, multiarm setting.

8.
Br J Haematol ; 183(2): 235-241, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30378121

RESUMO

This open-label, multicentre phase I/II study determined the maximum tolerated dose (MTD), safety and efficacy of clofarabine administered with cytarabine and idarubicin in newly diagnosed acute myeloid leukaemia (AML) patients lacking favourable genetic aberrations. The MTD was 30 mg/m2 clofarabine for patients below and above 60 years. The most frequently reported grade 3-4 non-haematological adverse events were infectious and gastrointestinal toxicities. Complete remission (CR)/CR with incomplete recovery rate was 67%. Allogeneic haematopoietic cell transplantation in first remission was feasible in a high proportion of younger AML patients and probably contributed to the favourable outcome compared to historical controls.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Clofarabina/administração & dosagem , Clofarabina/efeitos adversos , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Relação Dose-Resposta a Droga , Feminino , Transplante de Células-Tronco Hematopoéticas , Humanos , Idarubicina/administração & dosagem , Idarubicina/efeitos adversos , Quimioterapia de Indução/métodos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Indução de Remissão
9.
Oncoimmunology ; 7(8): e1450710, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30221040

RESUMO

We assessed the tolerability and antitumor activity of solitomab, a bispecific T-cell engager (BiTE®) antibody construct targeting epithelial cell adhesion molecule (EpCAM). Patients with relapsed/refractory solid tumors not amenable to standard therapy received solitomab as continuous IV infusion in a phase 1 dose-escalation study with six different dosing schedules. The primary endpoint was frequency and severity of adverse events (AEs). Secondary endpoints included pharmacokinetics, pharmacodynamics, immunogenicity, and antitumor activity. Sixty-five patients received solitomab at doses between 1 and 96 µg/day for ≥28 days. Fifteen patients had dose-limiting toxicities (DLTs): eight had transient abnormal liver parameters shortly after infusion start or dose escalation (grade 3, n = 4; grade 4, n = 4), and one had supraventricular tachycardia (grade 3); all events resolved with solitomab discontinuation. Six patients had a DLT of diarrhea: four events resolved (grade 3, n = 3; grade 4, n = 1), one (grade 3) was ongoing at the time of treatment-unrelated death, and one (grade 3) progressed to grade 5 after solitomab discontinuation. The maximum tolerated dose was 24 µg/day. Overall, 95% of patients had grade ≥3 treatment-related AEs, primarily diarrhea, elevated liver parameters, and elevated lipase. Solitomab half-life was 4.5 hours; serum levels plateaued within 24 hours. One unconfirmed partial response was observed. In this study of a BiTE® antibody construct targeting solid tumors, treatment of relapsed/refractory EpCAM-positive solid tumors with solitomab was associated with DLTs, including severe diarrhea and increased liver enzymes, which precluded dose escalation to potentially therapeutic levels.

10.
Oncotarget ; 8(17): 29187-29201, 2017 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-28418873

RESUMO

Activation of the Hedgehog pathway has been implicated in the pathogenesis of several tumor types including myeloid leukemia. Previously we demonstrated that overexpression of Hedgehog downstream mediators GLI1/2 confers an adverse prognosis to patients with acute myeloid leukemia (AML) and is correlated with a FLT3 mutated status. To analyze a possible non-canonical activation of the Hedgehog pathway via FLT3 and PI3K, we performed blocking experiments utilizing inhibitors for FLT3 (sunitinib), PI3K (PF-04691502) and GLI1/2 (GANT61) in FLT3-mutated and FLT3 wildtype AML cell lines and primary blasts. Combination of all three compounds had stronger anti-leukemic effects in FLT3-mutated compared to FLT3 wildtype AML cells in vitro. Interestingly, the colony growth of normal CD34+ cells from healthy donors was not impeded by the triple inhibitor combination possibly opening a therapeutic window for the clinical use of inhibitor combinations. Besides, combined treatment with sunitinib, PF-04691502 and GANT61 significantly prolonged the survival of mice transplanted with FLT3-mutated MV4-11 cells compared to the single agent treatments. Furthermore, the inhibition of FLT3 and PI3K resulted in reduced GLI protein expression and promotor activity in FLT3-mutated but not in FLT3 wildtype AML cell lines in western blotting and GLI1/2 promoter assays supporting our hypothesis of non-canonical GLI activation via FLT3.In summary, FLT3-mutated in contrast to FLT3 wildtype cells or normal human hematopoietic progenitor cells are exquisitely sensitive to combined inhibition by FLT3, PI3K and GLI1/2 overcoming some of the limitations of current FLT3 directed therapy in AML. The development of GLI1/2 inhibitors is highly desirable.


Assuntos
Proteínas Hedgehog/metabolismo , Leucemia Mieloide Aguda/genética , Proteína GLI1 em Dedos de Zinco/metabolismo , Tirosina Quinase 3 Semelhante a fms/metabolismo , Animais , Apoptose , Proliferação de Células , Modelos Animais de Doenças , Feminino , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Transdução de Sinais
11.
Oncotarget ; 7(22): 32532-42, 2016 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-27081038

RESUMO

RG7356, a recombinant anti-CD44 immunoglobulin G1 humanized monoclonal antibody, inhibits cell adhesion and has been associated with macrophage activation in preclinical models. We report results of a phase I dose-escalation study of RG7356 in relapsed/refractory acute myeloid leukemia (AML).Eligible patients with refractory AML, relapsed AML after induction chemotherapy, or previously untreated AML not eligible for intensive chemotherapy were enrolled and received intravenous RG7356 at dosages ≤ 2400 mg every other week or ≤ 1200 mg weekly or twice weekly; dose escalation started at 300 mg.Forty-four patients (median age, 69 years) were enrolled. One dose-limiting toxicity occurred (grade 3 hemolysis exacerbation) after one 1200 mg dose (twice-weekly cohort). The majority of adverse events were mild/moderate. Infusion-related reactions occurred in 64% of patients mainly during cycle 1. Two patients experienced grade 3 drug-induced aseptic meningitis. Pharmacokinetics increased supraproportionally, suggesting a target-mediated drug disposition (TMDD) at ≥ 1200 mg. Two patients achieved complete response with incomplete platelet recovery or partial response, respectively. One patient had stable disease with hematologic improvement.RG7356 was generally safe and well tolerated. Maximum tolerated dose was not reached, but saturation of TMDD was achieved. The recommended dose for future AML evaluations is 2400 mg every other week.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Leucemia Mieloide Aguda/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Feminino , Humanos , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
Br J Haematol ; 169(5): 694-700, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25818407

RESUMO

Acute myeloid leukaemia (AML) with FLT3 mutation has a dismal prognosis in elderly patients. Treatment with a combination of FLT3 inhibitors and standard chemotherapy has not been extensively studied. Therefore, we instigated a phase I/II clinical trial of chemotherapy with cytosine arabinoside (Ara-C)/daunorubicin induction (7+3) followed by three cycles of intermediate-dose Ara-C consolidation in 22 AML patients with activating FLT3 mutations. Sunitinib was added at predefined dose levels and as maintenance therapy for 2 years. At dose level 1, sunitinib 25 mg daily continuously from day 1 onwards resulted in two cases with dose-limiting toxicity (DLT), prolonged haemotoxicity and hand-foot syndrome. At dose level -1, sunitinib 25 mg was restricted to days 1-7 of each chemotherapy cycle. One DLT was observed in six evaluable patients. Six additional patients were treated in an extension phase. Thirteen of 22 patients (59%; 8/14 with FLT3-internal tandem duplication and 5/8 with FLT3-tyrosine kinase domain) achieved a complete remission/complete remission with incomplete blood count recovery. For the 17 patients included at the lower dose level, median overall, relapse-free and event-free survival were 1·6, 1·0 and 0·4 years, respectively. Four out of five analysed patients with relapse during maintenance therapy lost their initial FLT3 mutation, suggesting outgrowth of FLT3 wild-type subclones.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Mutação , Tirosina Quinase 3 Semelhante a fms/genética , Fatores Etários , Idoso , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Feminino , Humanos , Indóis/administração & dosagem , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Pirróis/administração & dosagem , Indução de Remissão , Sunitinibe , Resultado do Tratamento
13.
Cell Signal ; 27(2): 373-81, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25435423

RESUMO

The Hedgehog pathway plays an important role in the pathogenesis of several tumor types, including esophageal cancer. In our study, we show an expression of the ligand Indian hedgehog (Ihh) and its downstream mediator Gli-1 in primary resected adenocarcinoma tissue by immunohistochemistry and quantitative PCR in fifty percent of the cases, while matching healthy esophagus mucosa was negative for both proteins. Moreover, a functionally important regulation of Gli-1 by ErbB2-PI3K-mTORC signaling as well as a Gli-1-dependent regulation of Ihh in the ErbB2 amplified esophageal adenocarcinoma cell line OE19 was observed. Treatment of OE19 cells with the Her2 antibody trastuzumab, the PI3K-mTORC1 inhibitor NVP BEZ235 (BEZ235) or the knockdown of Akt1 resulted in a downregulation of Gli-1 and Ihh as well as in a reduction of viable OE19 cells in vitro. Interestingly, the Hedgehog receptor Smo, which acts upstream of Gli-1, was not expressed in OE19 cells and in the majority of primary human esophageal adenocarcinoma, suggesting a non-canonical upregulation of Gli-1 expression by the ErbB2-PI3K axis. To translate our findings into a therapeutic concept, we targeted ErbB2-PI3K-mTORC1 by trastuzumab and BEZ235, combining both compounds with the Gli-1/2 inhibitor GANT61. The triple combination led to significantly stronger reduction of tumor cell viability than cisplatinum or each biological alone. Therefore, concomitant blockage of the ErbB2-PI3K pathway and the Hedgehog downstream mediator Gli-1 may provide a new therapeutic strategy for esophageal cancer.


Assuntos
Adenocarcinoma/patologia , Neoplasias Esofágicas/patologia , Proteínas Hedgehog/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor ErbB-2/metabolismo , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos/imunologia , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/metabolismo , Esôfago/metabolismo , Esôfago/patologia , Células HEK293 , Humanos , Imidazóis/farmacologia , Alvo Mecanístico do Complexo 1 de Rapamicina , Complexos Multiproteicos/antagonistas & inibidores , Complexos Multiproteicos/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/genética , Piridinas/farmacologia , Pirimidinas/farmacologia , Quinolinas/farmacologia , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Receptor ErbB-2/imunologia , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Trastuzumab , Células Tumorais Cultivadas , Proteína GLI1 em Dedos de Zinco
14.
J Mol Endocrinol ; 41(1): 25-34, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18562675

RESUMO

Thyroid hormone 3,3',5-tri-iodothyronine (T3) regulates gene expression in a positive and negative manner. Here, we analyzed the regulation of a positively (mitochondrial glycerol-3-phosphate dehydrogenase) and negatively T3-regulated target gene (TSHalpha). Thyroid hormone receptor (TR) activates mGPDH but not TSH promoter fragments in a mammalian one-hybrid assay. Furthermore, we investigated functional consequences of targeting TR to DNA independent of its own DNA-binding domain (DBD). Using a chimeric fusion protein of the DBD of yeast transcription factor Gal4 with TR, we demonstrated a positive regulation of gene transcription in response to T3. T3-mediated activation of this chimeric protein is further increased after an introduction of point mutations within the DBD of TR. Moreover, we investigated the capacity of TR to negatively regulate gene transcription on a DNA-tethered cofactor platform. A direct binding of TR to DNA via its own DBD is dispensable in this assay. We investigated functional consequences of point mutations affecting different domains of TR. Our data indicate that the DBD of TR plays a key role in direct DNA binding on positively but not on negatively T3-regulated target genes. Nevertheless, the DBD is involved in mediating negative gene regulation independent of its capacity to bind DNA.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Regulação para Baixo/fisiologia , Receptores dos Hormônios Tireóideos/fisiologia , Transcrição Gênica , Tri-Iodotironina/fisiologia , Substituição de Aminoácidos/genética , Linhagem Celular , Linhagem Celular Tumoral , DNA de Neoplasias/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Ligação Proteica , Receptores dos Hormônios Tireóideos/genética , Receptores dos Hormônios Tireóideos/metabolismo , Regulação para Cima/fisiologia
15.
Mol Cell Endocrinol ; 287(1-2): 90-5, 2008 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-18336995

RESUMO

Thyroid hormone (T3) has a profound influence on normal development, differentiation and metabolism. T3 induces complex gene expression patterns raises the question of how these expression patterns might be regulated. Since the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) induces very similar cellular energy metabolic pathways, we investigated the molecular mechanism of T3 regulation of PGC-1alpha. PGC-1alpha is rapidly regulated by T3, both in vivo and in cell culture. Transient transfection experiments demonstrated binding of the thyroid hormone receptor (TR) to a response element located at -4kb upstream of the transcriptional start site within the PGC-1alpha gene. Introducing of a single copy of the -4kb TRE in a heterologous promoter context is sufficient to maintain T3 responsiveness. Chromatin immunoprecipitation analysis revealed increased histone acetylation upon stimulation of T3. Finally, TR binds the -4kb TRE in electrophoretic mobility shift assays, identifying PGC-1alpha as a direct target of TR action. Since T3 directly regulates PGC-1alpha and PGC-1alpha coactivates liganded TR, we suggest an autoregulatory feed-forward loop of PGC-1alpha activation upon T3 treatment.


Assuntos
Elementos de Resposta/genética , Transativadores/genética , Tri-Iodotironina/farmacologia , Acetilação/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Humanos , Fígado/citologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Hipófise/citologia , Hipófise/efeitos dos fármacos , Hipófise/metabolismo , Ratos , Ratos Wistar , Transativadores/metabolismo , Fatores de Transcrição
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