Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 140
Filtrar
1.
Plant J ; 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39145524

RESUMO

Xylan is one of the major hemicelluloses in plant cell walls and its xylosyl backbone is often decorated at O-2 with glucuronic acid (GlcA) and/or methylglucuronic acid (MeGlcA) residues. The GlcA/MeGlcA side chains may be further substituted with 2-O-arabinopyranose (Arap) or 2-O-galactopyranose (Gal) residues in some plant species, but the enzymes responsible for these substitutions remain unknown. During our endeavor to investigate the enzymatic activities of Arabidopsis MUR3-clade members of the GT47 glycosyltransferase family, we found that one of them was able to transfer Arap from UDP-Arap onto O-2 of GlcA side chains of xylan, and thus it was named xylan 2-O-arabinopyranosyltransferase 1 (AtXAPT1). The function of AtXAPT1 was verified in planta by its T-DNA knockout mutation showing a loss of the Arap substitution on xylan GlcA side chains. Further biochemical characterization of XAPT close homologs from other plant species demonstrated that while the poplar ones had the same catalytic activity as AtXAPT1, those from Eucalyptus, lemon-scented gum, sea apple, 'Ohi'a lehua, duckweed and purple yam were capable of catalyzing both 2-O-Arap and 2-O-Gal substitutions of xylan GlcA side chains albeit with differential activities. Sequential reactions with XAPTs and glucuronoxylan methyltransferase 3 (GXM3) showed that XAPTs acted poorly on MeGlcA side chains, whereas GXM3 could efficiently methylate arabinosylated or galactosylated GlcA side chains of xylan. Furthermore, molecular docking and site-directed mutagenesis analyses of Eucalyptus XAPT1 revealed critical roles of several amino acid residues at the putative active site in its activity. Together, these findings establish that XAPTs residing in the MUR3 clade of family GT47 are responsible for 2-O-arabinopyranosylation and 2-O-galactosylation of GlcA side chains of xylan.

2.
Planta ; 259(5): 115, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589536

RESUMO

MAIN CONCLUSION: A member of the rice GT61 clade B is capable of transferring both 2-O-xylosyl and 2-O-arabinosyl residues onto xylan and another member specifically catalyses addition of 2-O-xylosyl residue onto xylan. Grass xylan is substituted predominantly with 3-O-arabinofuranose (Araf) as well as with some minor side chains, such as 2-O-Araf and 2-O-(methyl)glucuronic acid [(Me)GlcA]. 3-O-Arabinosylation of grass xylan has been shown to be catalysed by grass-expanded clade A members of the glycosyltransferase family 61. However, glycosyltransferases mediating 2-O-arabinosylation of grass xylan remain elusive. Here, we performed biochemical studies of two rice GT61 clade B members and found that one of them was capable of transferring both xylosyl (Xyl) and Araf residues from UDP-Xyl and UDP-Araf, respectively, onto xylooligomer acceptors, whereas the other specifically catalysed Xyl transfer onto xylooligomers, indicating that the former is a xylan xylosyl/arabinosyl transferase (named OsXXAT1 herein) and the latter is a xylan xylosyltransferase (named OsXYXT2). Structural analysis of the OsXXAT1- and OsXYXT2-catalysed reaction products revealed that the Xyl and Araf residues were transferred onto O-2 positions of xylooligomers. Furthermore, we demonstrated that OsXXAT1 and OsXYXT2 were able to substitute acetylated xylooligomers, but only OsXXAT1 could xylosylate GlcA-substituted xylooligomers. OsXXAT1 and OsXYXT2 were predicted to adopt a GT-B fold structure and molecular docking revealed candidate amino acid residues at the predicted active site involved in binding of the nucleotide sugar donor and the xylohexaose acceptor substrates. Together, our results establish that OsXXAT1 is a xylan 2-O-xylosyl/2-O-arabinosyl transferase and OsXYXT2 is a xylan 2-O-xylosyltransferase, which expands our knowledge of roles of the GT61 family in grass xylan synthesis.


Assuntos
Arabidopsis , Oryza , Glicosiltransferases/análise , Oryza/metabolismo , Xilanos/metabolismo , Arabidopsis/metabolismo , Simulação de Acoplamento Molecular , UDP Xilose-Proteína Xilosiltransferase , Poaceae/metabolismo , Parede Celular/metabolismo
3.
BMC Cancer ; 22(1): 349, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35361149

RESUMO

BACKGROUND: The prognosis of patients with relapsed Ewing sarcoma is poor. In this study, we aimed to pooled-analyze the efficacy and safety of the combination of irinotecan and temozolomide in treating patients with relapsed Ewing sarcoma. METHODS: PubMed, Cochrane CENTRAL, Web of Science, and EMBASE were systematically searched on September 27, 2021. The primary outcomes were rates of objective response and disease control, and the secondary outcomes were toxicities. RESULTS: Six retrospective studies with 184 patients were enrolled in the analysis. The median age ranged from 14 to 21. The integrated rates were 44% (95% confidence interval [CI] 31-58) for objective response and 66% (55-77) for disease control. Grade 3-4 neutropenia, thrombocytopenia, and diarrhea occurred in 8% (3-16), 7% (3-11), and 8% (5-10) of chemotherapeutic cycles, respectively. 18% (7-32) and 6% (2-11) of patients suffered grade 3-4 neutropenia and thrombocytopenia after irinotecan plus temozolomide treatment. CONCLUSION: Irinotecan plus temozolomide combination chemotherapy showed antitumor activity and an acceptable safety profile in patients with relapsed Ewing sarcoma. More future prospective studies are needed to confirm the retrospective results.


Assuntos
Neutropenia , Sarcoma de Ewing , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Camptotecina , Dacarbazina/efeitos adversos , Humanos , Irinotecano/uso terapêutico , Recidiva Local de Neoplasia/tratamento farmacológico , Estudos Retrospectivos , Sarcoma de Ewing/tratamento farmacológico , Temozolomida/uso terapêutico
4.
Dermatol Ther ; 35(9): e15715, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35821497

RESUMO

Cemiplimab has been widely recommended by international guidelines to treat patients with locally advanced or metastatic cutaneous squamous cell carcinoma (CSCC). In this study, we conducted a comparative analysis to integrate the efficacy and safety data in the published prospective and retrospective studies for better understanding the application of cemiplimab. The online databases (PubMed, Cochrane CENTRAL, Web of Science, and EMBASE) were searched to find out eligible studies from inception to November 4, 2021. The "R" software and the "meta" package were used to synthesize the objective response rates (ORRs), disease control rates (DCRs), and the incidences of treatment-related adverse events (TRAEs). Overall, three retrospective studies with 398 patients and three prospective studies with 219 patients were enrolled. The pooled ORR and DCR were 53% (95% confidence interval [CI] 46-59) and 70% (95% CI 57-82) for retrospective studies versus 45% (95% CI 39-52) and 68% (95% CI 56-79) for prospective studies. In regard of toxicities, prospective studies reported much higher incidences of any grade (99% vs. 47%) and grade 3-4 TRAEs (43% vs. 15%) against retrospective studies. The most reported TRAE was fatigue, followed by diarrhea and pruritus. In addition, nine treatment-related deaths (four in retrospective studies vs. five in prospective studies) were documented. In both retrospective and prospective clinical practices, cemiplimab could be an effective regimen for locally advanced or metastatic CSCC patients, but toxicities during the treatment deserve further attention.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Cutâneas , Anticorpos Monoclonais Humanizados , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia
5.
Support Care Cancer ; 30(3): 2445-2453, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34775535

RESUMO

PURPOSE: As an antipsychotic agent that targets multiple neurotransmitter receptors, olanzapine has been added to antiemetic therapies. For better understanding the application of olanzapine in antiemetic strategies for breast cancer patients who suffered anthracycline plus cyclophosphamide-induced nausea and vomiting, we comprehensively reviewed the antiemetic researches related to olanzapine and pooled-analyzed the results to confirm the efficacy and safety of olanzapine in breast cancer. METHODS: PubMed, Web of Science, EMBASE, and Cochrane CENTRAL databases were searched from inception through Sep 15, 2021. Both prospective and retrospective studies were eligible. The primary outcomes were complete response (defined as no vomiting and no use of rescue medications) and no nausea rate, and the secondary outcome was treatment-related adverse events. RESULTS: Four studies with 466 breast cancer patients were identified in the pooled analysis. In the acute period (0-24 h), the olanzapine group had significantly higher rates of complete response (71.3% vs 48.1%, odds ratio [OR]: 2.66, 95% confidence interval [CI] 1.39-5.11, p = 0.003) and no nausea (70.0% vs 43.0%, OR: 3.55, 95% CI 1.76-7.18, p = 0.04) than the placebo group, while in the delayed period, the olanzapine group was also superior to the placebo group in terms of the complete response (82.5% vs 63.3%, OR: 3.81, 95% CI 1.58-9.15, p = 0.003) and no nausea (66.3% vs 51.9%, OR: 2.08, 95% CI 1.03-4.21, p = 0.04) rates. During the overall period in prospective studies, the proportions of complete response (50.0% vs 34.2%, OR: 1.93, p = 0.04) and no nausea (51.3% vs 25.3%, OR: 3.40, p = 0.0006) in the olanzapine group were higher than those in the placebo group. CONCLUSION: Highly emetogenic chemotherapy breast patients could benefit from olanzapine-contained antiemetic therapy. Furthermore, since the cost is low, olanzapine is worth further clinical application and promotion.


Assuntos
Antieméticos , Antineoplásicos , Neoplasias da Mama , Antraciclinas/efeitos adversos , Antieméticos/uso terapêutico , Antineoplásicos/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Ciclofosfamida/efeitos adversos , Dexametasona/uso terapêutico , Feminino , Humanos , Olanzapina/uso terapêutico , Estudos Prospectivos , Estudos Retrospectivos , Vômito/induzido quimicamente , Vômito/tratamento farmacológico
6.
BMC Cancer ; 20(1): 393, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32375701

RESUMO

BACKGROUND: Induction chemotherapy (IC) combined with concurrent chemoradiotherapy (CCRT) has been recommended as the first-line therapy for locoregional nasopharyngeal carcinoma (NPC). Due to the different chemotherapeutic drugs used in the IC and CCRT, the results remain controversial. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library databases were systematically retrieved to search potentially eligible clinical trials up to Sep 11, 2019. Eligible studies were registered and prospective randomized controlled clinical trials. RESULTS: From 526 records, nine articles including seven randomized controlled clinical trials were eligible, with a total of 2311 locoregional advanced NPC patients. IC + CCRT had significantly lower risks of death (3-year hazard ratio [HR]: 0.70, 95% confidence interval [CI] 0.55-0.89, p = 0.003; 5-year HR: 0.77, 95% CI 0.62-0.94, p = 0.01), disease progression (3-year HR: 0.67, 95% CI 0.55-0.80, p < 0.001; 5-year HR: 0.70, 95% CI 0.58-0.83, p < 0.0001), distant metastasis (3-year HR: 0.58, 95% CI 0.45-0.74, p < 0.0001; 5-year HR: 0.69, 95% CI 0.55-0.87, p = 0.001) and locoregional relapse (3-year HR: 0.69, 95% CI 0.50-0.95, p = 0.02; 5-year HR: 0.66, 95% CI 0.51-0.86, p = 0.002) than CCRT. Compared with CCRT, IC + CCRT showed higher relative risks of grade 3 or more neutropenia, thrombocytopenia, nausea, vomiting and hepatotoxicity throughout the course of treatment, and higher relative risks of grade ≥ 3 thrombocytopenia and vomiting during CCRT. CONCLUSION: IC combined with CCRT significantly improved the survival in locoregional advanced NPC patients. Moreover, toxicities were well tolerated during IC and CCRT. Further clinical trials are warranted to confirm the optimal induction chemotherapeutic regimen in the future.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimiorradioterapia/mortalidade , Quimioterapia de Indução/mortalidade , Carcinoma Nasofaríngeo/mortalidade , Neoplasias Nasofaríngeas/mortalidade , Progressão da Doença , Humanos , Carcinoma Nasofaríngeo/patologia , Carcinoma Nasofaríngeo/terapia , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/terapia , Prognóstico , Taxa de Sobrevida
7.
Ann Pharmacother ; 54(6): 517-525, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31855061

RESUMO

Background: The addition of bevacizumab to neoadjuvant chemotherapy improves the pathological complete response rate of human epidermal growth factor 2 (HER2)-negative breast cancer patients. However, the characteristics of adverse events associated with the use of bevacizumab should receive more attention from clinicians. Objective: This meta-analysis aimed to detect the adverse events of adding bevacizumab to neoadjuvant chemotherapy compared with neoadjuvant chemotherapy alone in HER2-negative breast cancer patients. Methods: PubMed, Cochrane Library, Web of Science, and EMBASE databases were systematically accessed to find eligible studies from January 1, 2000, to October 20, 2019. Reference lists were searched for additional studies. Pooled risk ratios for adverse events of bevacizumab were meta-analyzed. Results: Overall, 6 of 829 initially identified studies met the inclusion criteria, with 4681 patients randomized (2321 in the bevacizumab plus neoadjuvant chemotherapy group and 2360 in the neoadjuvant chemotherapy group). The incidence of grade ≥3 hypertension, left-ventricular dysfunction, mucositis, febrile neutropenia, infection, pain, hand-foot syndrome, hemorrhage, and neutropenia significantly increased in patients treated with bevacizumab plus neoadjuvant chemotherapy. However, adding bevacizumab to neoadjuvant chemotherapy was not associated with increasing the incidences of grade ≥3 proteinuria, dyspnea, heart failure, peripheral neurotoxicity, thrombosis, thrombocytopenia, fatigue, leucopenia, vomiting, nausea, and diarrhea. Conclusion and Relevance: Adding bevacizumab to neoadjuvant chemotherapy to treat HER2-negative breast cancer patients increased adverse events. However, most adverse events are clinically manageable. Patients, therefore, need to be monitored carefully for hypertension, left-ventricular dysfunction, mucositis, febrile neutropenia, infection, pain, hand-foot syndrome, hemorrhage, and neutropenia when treated with bevacizumab and neoadjuvant chemotherapy simultaneously.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Terapia Neoadjuvante/efeitos adversos , Receptor ErbB-2/genética , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bevacizumab/administração & dosagem , Bevacizumab/uso terapêutico , Monitoramento de Medicamentos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Feminino , Humanos , Pessoa de Meia-Idade
8.
Cell Physiol Biochem ; 46(2): 532-545, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29614511

RESUMO

BACKGROUND/AIMS: Exosomal circulating long non-coding RNAs (lncRNAs) in blood are emerging as clinically useful and non-invasive biomarkers for tumor diagnosis. However, normal cells can also secrete exosomes, so it is a prerequisite to obtain tumor-derived exosomes for better understanding of their diagnostic impacts in cancer. In this study, a dual-antibody-functionalized immunoaffinity system was established to isolate exosomes and investigate their lncRNAs expression pattern and clinical significance in prostate cancer (PCa). METHODS: A commercially available kit was used to isolate total exosomes, which were then purified by a dual-antibody-functionalized immunoaffinity system. RT-qPCR was performed to detect the expression of exosomal lncRNAs. Receiver operating characteristic (ROC) curves were plotted to assess the diagnostic value. RESULTS: Expression levels of two lncRNAs in tumor-derived exosomes were significantly higher than those in total exosomes. The levels of SAP30L-AS1 were upregulated in benign prostatic hyperplasia (BPH), and SChLAP1 levels were significantly higher in PCa than in BPH and healthy individuals. The area under the ROC curve indicated that SAP30L-AS1 and SChLAP1 had adequate diagnostic value to distinguish PCa from controls. Two lncRNAs separately combined with prostate specific antigen (PSA) possessed a moderate ability for discrimination. SAP30L-AS1 expression level was related to PSA values and tumor invasion. SChLAP1 expression was significantly higher in patients with higher Gleason scores, and was also effective in differentiating between BPH and PCa when the concentration of PSA was in the gray zone. CONCLUSION: The isolation of tumor-derived exosomes by dual-antibody-functionalized immunoaffinity systems and detection of their lncRNAs in plasma may lead to the identification of suitable biomarkers, with potential diagnostic utility.


Assuntos
Biomarcadores Tumorais/metabolismo , Exossomos/genética , Neoplasias da Próstata/diagnóstico , RNA Longo não Codificante/metabolismo , Idoso , Antígenos de Superfície/metabolismo , Área Sob a Curva , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Difusão Dinâmica da Luz , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Molécula de Adesão da Célula Epitelial/metabolismo , Exossomos/metabolismo , Glutamato Carboxipeptidase II/metabolismo , Humanos , Masculino , Microscopia Eletrônica de Transmissão , Gradação de Tumores , Antígeno Prostático Específico/sangue , Hiperplasia Prostática/genética , Hiperplasia Prostática/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Curva ROC , Tetraspanina 30/metabolismo , Fatores de Transcrição/metabolismo , Regulação para Cima
9.
Nat Methods ; 12(2): 131-3, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25506719

RESUMO

We describe a data collection method that uses a single crystal to solve X-ray structures by native SAD (single-wavelength anomalous diffraction). We solved the structures of 11 real-life examples, including a human membrane protein, a protein-DNA complex and a 266-kDa multiprotein-ligand complex, using this method. The data collection strategy is suitable for routine structure determination and can be implemented at most macromolecular crystallography synchrotron beamlines.


Assuntos
Proteínas de Ligação a DNA/química , Proteínas de Membrana/química , Complexos Multiproteicos/química , Difração de Raios X/métodos , Animais , Humanos , Modelos Moleculares , Conformação Proteica , Software , Síncrotrons
10.
Cell Physiol Biochem ; 38(3): 1157-70, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26963129

RESUMO

BACKGROUND/AIM: Triple-negative breast cancer (TNBC) represents a particular clinical challenge because these cancers do not respond to endocrine therapy or other available targeted agents. The lack of effective agents and obvious targets are major challenges in treating TNBC. In this study we explored the cytostatic effect of thiazole ring containing antibiotic drug thiostrepton on TNBC cell lines and investigated the molecular mechanism. METHODS: Cell viability was measured by MTT assay. Cell surface marker was monitored by FCM. Western blot was applied to assess the protein expression levels of target genes. RESULTS: We found that thiostrepton remarkably suppressed the CD44+/CD24- stem-like population and sphere forming capacity of TNBC cell lines. Notably, we showed for the first time that thiostrepton exerted its pharmacological action by targeting sonic hedgehog (SHH) signaling pathway. Thiostrepton repressed SHH ligand expression and reduced Gli-1 nuclear localization in TNBC cell line. Furthermore, the downstream target of SHH signaling undergone dose-dependent, rapid, and sustained loss of mRNA transcript level after thiostrepton treatment. Finally, we showed that SHH ligand was essential for maintaining CD44+/CD24- stem-like population in TNBC cell line. CONCLUSION: We conclude that thiostrepton suppresses the CD44+/CD24- stem-like population through inhibition of SHH signaling pathway. Our results give a new insight into the mechanism of thiostrepton anti-tumor activity and suggest thiostrepton as a promising agent that targets hedgehog signaling pathway in TNBC.


Assuntos
Antineoplásicos/farmacologia , Proteínas Hedgehog/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Esferoides Celulares/efeitos dos fármacos , Tioestreptona/farmacologia , Neoplasias de Mama Triplo Negativas/metabolismo , Antibacterianos/farmacologia , Antígeno CD24/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas Hedgehog/genética , Humanos , Receptores de Hialuronatos/metabolismo , Células MCF-7 , Células-Tronco Neoplásicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Esferoides Celulares/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia
11.
Arch Biochem Biophys ; 602: 80-94, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27036852

RESUMO

Single wavelength anomalous diffraction (SAD) can trace its beginnings to the early 1950s. Researchers at the time recognized that SAD offers some unique features that might be advantageous for crystallographic phasing, despite the fact that at that time recording accurate SAD data was problematic. In this review we will follow the trail from those early days, highlighting key advances in the field and interpreting them in terms on how they stimulated continued phasing development that produced the theoretical foundation for the routine macromolecular structure determination by SAD today. The technological advances over the past three decades in both hardware and software, which played a significant role in making SAD phasing a 'first choice method', will also be described.


Assuntos
Modelos Moleculares , Proteínas/química , Proteínas/ultraestrutura , Difração de Raios X/métodos , Difração de Raios X/tendências , Simulação por Computador , Previsões , Conformação Proteica
12.
Biochem Biophys Res Commun ; 462(3): 184-9, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-25957471

RESUMO

The structures of several Bacillus thuringiensis (Bt) insecticidal crystal proteins have been determined by crystallographic methods and a close relationship has been explicated between specific toxicities and conserved three-dimensional architectures. In this study, as a representative of the coleopteran- and hemipteran-specific Cry51A group, the complete structure of Cry51Aa1 protoxin has been determined by X-ray crystallography at 1.65 Å resolution. This is the first report of a coleopteran-active Bt insecticidal toxin with high structural similarity to the aerolysin-type ß-pore forming toxins (ß-PFTs). Moreover, study of featured residues and structural elements reveal their possible roles in receptor binding and pore formation events. This study provides new insights into the action of aerolysin-type ß-PFTs from a structural perspective, and could be useful for the control of coleopteran and hemipteran insect pests in agricultures.


Assuntos
Bacillus thuringiensis/química , Proteínas de Bactérias/química , Toxinas Bacterianas/química , Endotoxinas/química , Proteínas Hemolisinas/química , Proteínas Citotóxicas Formadoras de Poros/química , Sequência de Aminoácidos , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Besouros , Cristalografia por Raios X , Endotoxinas/genética , Proteínas Hemolisinas/genética , Modelos Moleculares , Dados de Sequência Molecular , Controle Biológico de Vetores , Proteínas Citotóxicas Formadoras de Poros/genética , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Quaternária de Proteína , Homologia de Sequência de Aminoácidos
13.
Biochim Biophys Acta ; 1834(10): 2139-46, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23891746

RESUMO

The bright bioluminescence of ctenophores, found in oceans worldwide, is determined by Ca(2+)-regulated photoproteins, functionally identical to and sharing many properties of hydromedusan photoproteins. In contrast, however, the ctenophore photoproteins are extremely sensitive to UV and visible light over the range of their absorption spectrum. The spatial structure of a novel light-sensitive photoprotein from the ctenophore Beroe abyssicola in its apoform bound with three calcium ions is determined at 2.0Å. We demonstrate that the apoberovin is a slightly asymmetrical compact globular protein formed by two domains with a cavity in the center, which exactly retains the fold architecture characteristic of hydromedusan photoproteins despite their low amino acid sequence identity. However, the structural alignment of these two photoprotein classes clearly shows that despite the high similarity of shape and geometry of their coelenterazine-binding cavities, their interiors differ drastically. The key residues appearing to be crucial for stabilizing the 2-hydroperoxycoelenterazine and for formation of the emitter in hydromedusan photoproteins, are replaced in berovin by amino acid residues having completely different side chain properties. Evidently, these replacements must be responsible for the distinct properties of ctenophore photoproteins such as sensitivity to light or the fact that the formation of active photoprotein from apophotoprotein, coelenterazine, and oxygen is more effective at alkaline pH.


Assuntos
Aminoácidos/química , Apoproteínas/química , Cálcio/química , Ctenóforos/química , Imidazóis/química , Proteínas Luminescentes/química , Pirazinas/química , Proteínas Recombinantes/química , Sequência de Aminoácidos , Aminoácidos/genética , Animais , Apoproteínas/genética , Cristalografia por Raios X , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Luz , Medições Luminescentes , Proteínas Luminescentes/genética , Modelos Moleculares , Dados de Sequência Molecular , Oxigênio/química , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Alinhamento de Sequência
14.
Target Oncol ; 19(2): 203-212, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38289445

RESUMO

BACKGROUND: Immunotherapy has revolutionized the treatment of hepatocellular carcinoma (HCC). However, whether adding immunotherapy to antiangiogenic therapy benefits patients with unresectable HCC (uHCC) more in the first-line setting remains controversial. OBJECTIVE: In this analysis, we compared the clinical outcomes of lenvatinib monotherapy with atezolizumab plus bevacizumab combination therapy in advanced uHCC in real-world clinical practice. METHODS: The MEDLINE, Embase, and Cochrane CENTRAL databases were systematically searched on 23 April 2023. The "metaSurvival" and "meta" packages of the R software (version 4.2.2) were used to summarize the survival curves and meta-analyze the survival data. Overall survival (OS) and progression-free survival (PFS) were defined as dual primary endpoints. Secondary endpoints included the objective response rate (ORR) and disease control rate (DCR). RESULTS: Overall, the pooled median OS was 18.4 months in the lenvatinib group versus 18.5 months in the atezolizumab plus bevacizumab group; the pooled median PFS was 6.9 months in the lenvatinib group versus 7.3 months in the atezolizumab plus bevacizumab group. Lenvatinib therapy showed similar OS [hazard ratio (HR): 0.91, 95% confidence interval (CI): 0.55-1.52, p = 0.72] and PFS (HR: 0.79, 95% CI: 0.56-1.12, p = 0.19) compared with atezolizumab plus bevacizumab therapy. In addition, a comparable ORR [odds ratio (OR): 0.89, 95% CI: 0.65-1.20, p = 0.44) was observed between lenvatinib and atezolizumab plus bevacizumab. CONCLUSIONS: Comprehensive analysis suggested that lenvatinib monotherapy exhibited survival outcomes comparable to those of atezolizumab plus bevacizumab combination therapy, which may provide useful insights for clinicians in future clinical practice.


Assuntos
Anticorpos Monoclonais Humanizados , Carcinoma Hepatocelular , Neoplasias Hepáticas , Compostos de Fenilureia , Quinolinas , Humanos , Bevacizumab/farmacologia , Bevacizumab/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico
15.
Front Endocrinol (Lausanne) ; 15: 1385747, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38988997

RESUMO

Background: For patients with anaplastic thyroid cancer (ATC) without mutational driver genes, chemotherapy is suggested to be the first-line treatment option. However, the benefits of chemotherapy in treating ATC are limited. In this analysis, we collected the prospective data reported since 2010 to analyze the emerging chemotherapy-based treatments in ATC comprehensively. Methods: For this updated analysis, we searched PubMed (MEDLINE), Web of Science, Embase, and Cochrane CENTRAL databases from 1 January 2010 to 7 February 2024 for prospective clinical studies that contained chemotherapy-based treatments. This analysis was done to pool overall survival (OS), progression-free survival (PFS), objective response rates (ORRs), disease control rates (DCRs), and grade 3 or worse treatment-related adverse events (TRAEs). Results: Six prospective clinical trials with 232 patients were included. Chemotherapy was commonly combined with targeted therapy or radiotherapy. The pooled median OS was 6.0 months (95% CI 4.1-9.7), and the median PFS was 3.2 months (95% CI 1.9-6.0) in patients with ATC who received chemotherapy-based strategies. The integrated ORR and DCR were 21% (95% CI 15%-27%) and 64% (95% CI 55%-72%), respectively. Regarding the grade 3 or worse TRAE, the pooled incidence was 68% (95% CI 47%-86%). Conclusion: Although the emerging chemotherapy-based treatments showed antitumor activity in patients with ATC, these strategies failed to prolong the survival time substantially. More practical, safe, and novel therapeutic regimens for patients with ATC warrant further investigations.


Assuntos
Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide , Humanos , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Estudos Prospectivos , Carcinoma Anaplásico da Tireoide/tratamento farmacológico , Carcinoma Anaplásico da Tireoide/patologia , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/mortalidade
16.
Oncol Lett ; 27(5): 192, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38495833

RESUMO

As a novel tyrosine kinase inhibitor (TKI), pyrotinib can irreversibly block dual pan-ErbB receptors and has been used in the treatment of advanced or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, there are limited data on the use of pyrotinib in early breast cancer. Therefore, the present meta-analysis was conducted to evaluate the safety and efficacy of pyrotinib in the neoadjuvant setting for patients with early-stage or locally advanced HER2-positive breast cancer. Online databases (Pubmed, Web of Science, Embase and Cochrane Library) were comprehensively searched for eligible prospective clinical trials on August 17, 2023. The primary endpoint was the treatment-related adverse events (TRAEs), and the secondary endpoint was pathological complete response (pCR) rate. In total, seven trials with a total enrolment of 407 patients were included. A total of seven studies evaluated pyrotinib in combination with trastuzumab and chemotherapy in the neoadjuvant setting. The median age ranged from 47-50 years. The most common TRAEs were diarrhea [98% of patients; 95% confidence interval (CI): 92-100%], followed by anemia (71%; 95% CI: 55-89%), vomiting (69%; 95% CI: 55-82%), and leucopenia (66%; 95% CI: 35-91%). No treatment-related deaths occurred. The pooled pCR rate was 57% (95% CI: 47-68%). It was concluded that pyrotinib-containing neoadjuvant therapy could be an effective treatment strategy in patients with early-stage or locally advanced HER2-positive breast cancer; however, the management of adverse events should be a key consideration. The management of adverse events should be paid great attention to, during pyrotinib therapy, although pyrotinib-contained neoadjuvant therapy could be an effective treatment for patients with early-stage or locally advanced HER2-positive breast cancer. Head-to-head randomized clinical trials are warranted to further confirm the benefits and risks associated with pyrotinib therapy in patients with breast cancer.

17.
Front Endocrinol (Lausanne) ; 15: 1345203, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38469143

RESUMO

Background: Tyrosine kinase inhibitors (TKIs) contribute to the treatment of patients with anaplastic thyroid cancer (ATC). Although prospective clinical studies of TKIs exhibit limited efficacy, whether ATC patients benefit from TKI treatment in real-world clinical practice may enlighten future explorations. Therefore, we conducted this effective analysis based on real-world retrospective studies to illustrate the efficacy of TKI treatment in ATC patients. Methods: We systematically searched the online databases on September 03, 2023. Survival curves were collected and reconstructed to summarize the pooled curves. Responses were analyzed by using the "meta" package. The primary endpoints were progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and disease control rate (DCR). Results: 12 studies involving 227 patients were enrolled in the study. Therapeutic strategies included: anlotinib, lenvatinib, dabrafenib plus trametinib, vemurafenib, pembrolizumab plus dabrafenib and trametinib, pembrolizumab plus lenvatinib, pembrolizumab plus trametinib, and sorafenib. The pooled median OS and PFS were 6.37 months (95% CI 4.19-10.33) and 5.50 months (95% CI 2.17-12.03). The integrated ORR and DCR were 32% (95% CI 23%-41%) and 40% (95% CI 12%-74%). Conclusion: In real-world clinical practice, ATC patients could benefit from TKI therapy. In future studies, more basic experiments and clinical explorations are needed to enhance the effects of TKIs in the treatment of patients with ATC.


Assuntos
Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide , Humanos , Intervalo Livre de Progressão , Estudos Retrospectivos , Carcinoma Anaplásico da Tireoide/tratamento farmacológico , Carcinoma Anaplásico da Tireoide/mortalidade , Carcinoma Anaplásico da Tireoide/patologia , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/mortalidade , /uso terapêutico
18.
Medicine (Baltimore) ; 103(31): e38679, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39093805

RESUMO

BACKGROUND: The poor prognosis of anaplastic thyroid cancer (ATC) patients is associated with limited effective therapeutic strategies. Multiple antiangiogenesis tyrosine kinase inhibitors (TKIs) have been applied in later-line treatment of ATC; however, the results reported in clinical trials were controversial. In this study, we reconstructed the patient-level data to pooled-analyze the survival data, responses, and adverse events. METHODS: Online databases (PubMed, Web of Science, Embase, and Cochrane CENTRAL) were searched on September 03, 2023. R software combined with the "metaSurvival" and "meta" packages were used to reconstruct the survival curves and summarize the response rates. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The secondary endpoints were survival rate, objective response rate (ORR), disease control rate (DCR), and treatment-related adverse events. RESULTS: Six prospective clinical trials involving 140 ATC patients were enrolled. Four types of TKIs (imatinib, pazopanib, sorafenib, and lenvatinib) were included. When advanced ATC patients were treated with the TKIs, the median OS was 4.8 months and the median PFS was 2.6 months. The pooled ORR and DCR were 9% and 53%. Hypertension, decreased appetite, rash, and lymphopenia were the most common grade ≥ 3 treatment-related adverse events. CONCLUSION: Mono-anitangiogenesis TKI therapy showed limited improvements in treating advanced ATC patients. Combining antiangiogenesis TKI therapy with chemotherapy, radiotherapy, or immunotherapy could be the direction of future studies.


Assuntos
Inibidores da Angiogênese , Inibidores de Proteínas Quinases , Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide , Humanos , Carcinoma Anaplásico da Tireoide/tratamento farmacológico , Inibidores da Angiogênese/uso terapêutico , Inibidores da Angiogênese/efeitos adversos , Neoplasias da Glândula Tireoide/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Inibidores de Proteínas Quinases/efeitos adversos , Estudos Prospectivos , Sorafenibe/uso terapêutico , Sorafenibe/efeitos adversos , Indazóis/uso terapêutico , Indazóis/efeitos adversos , Compostos de Fenilureia/uso terapêutico , Compostos de Fenilureia/efeitos adversos , Intervalo Livre de Progressão , Pirimidinas , Quinolinas , Sulfonamidas
19.
Plants (Basel) ; 13(16)2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39204739

RESUMO

Plant cell walls are largely composed of polysaccharide polymers, including cellulose, hemicelluloses (xyloglucan, xylan, mannan, and mixed-linkage ß-1,3/1,4-glucan), and pectins. Among these cell wall polysaccharides, xyloglucan, xylan, mannan, and pectins are often O-acetylated, and polysaccharide O-acetylation plays important roles in cell wall assembly and disease resistance. Genetic and biochemical analyses have implicated the involvement of three groups of proteins in plant cell wall polysaccharide O-acetylation: trichome birefringence-like (TBL)/domain of unknown function 231 (DUF231), reduced wall acetylation (RWA), and altered xyloglucan 9 (AXY9). Although the exact roles of RWAs and AXY9 are yet to be identified, members of the TBL/DUF231 family have been found to be O-acetyltransferases responsible for the O-acetylation of xyloglucan, xylan, mannan, and pectins. Here, we provide a comprehensive overview of the occurrence of O-acetylated cell wall polysaccharides, the biochemical properties, structural features, and evolution of cell wall polysaccharide O-acetyltransferases, and the potential biotechnological applications of manipulations of cell wall polysaccharide acetylation. Further in-depth studies of the biochemical mechanisms of cell wall polysaccharide O-acetylation will not only enrich our understanding of cell wall biology, but also have important implications in engineering plants with increased disease resistance and reduced recalcitrance for biofuel production.

20.
Acta Crystallogr D Biol Crystallogr ; 69(Pt 6): 1160-70, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23695260

RESUMO

Dual-specificity phosphatases (DUSPs) play an important role in regulating cellular signalling pathways governing cell growth, differentiation and apoptosis. Human DUSP26 inhibits the apoptosis of cancer cells by dephosphorylating substrates such as p38 and p53. High-resolution crystal structures of the DUSP26 catalytic domain (DUSP26-C) and its C152S mutant [DUSP26-C (C152S)] have been determined at 1.67 and 2.20 Å resolution, respectively. The structure of DUSP26-C showed a novel type of domain-swapped dimer formed by extensive crossover of the C-terminal α7 helix. Taken together with the results of a phosphatase-activity assay, structural comparison with other DUSPs revealed that DUSP26-C adopts a catalytically inactive conformation of the protein tyrosine phosphate-binding loop which significantly deviates from that of canonical DUSP structures. In particular, a noticeable difference exists between DUSP26-C and the active forms of other DUSPs at the hinge region of a swapped C-terminal domain. Additionally, two significant gaps were identified between the catalytic core and its surrounding loops in DUSP26-C, which can be exploited as additional binding sites for allosteric enzyme regulation. The high-resolution structure of DUSP26-C may thus provide structural insights into the rational design of DUSP26-targeted anticancer drugs.


Assuntos
Fosfatases de Especificidade Dupla/química , Fosfatases da Proteína Quinase Ativada por Mitógeno/química , Proteínas Mutantes/química , Calorimetria , Domínio Catalítico , Fosfatases de Especificidade Dupla/genética , Fosfatases de Especificidade Dupla/metabolismo , Humanos , Fosfatases da Proteína Quinase Ativada por Mitógeno/genética , Fosfatases da Proteína Quinase Ativada por Mitógeno/metabolismo , Mutagênese , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA