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The tripartite interaction motif (TRIM) family of proteins is known for their antiviral activity through different mechanisms, such as interfering with viral components, regulating immune responses, and participating in autophagy-mediated defense pathways. In this study, we investigated the role of tripartite interaction motif 26 (TRIM26), which is encoded by a major histocompatibility complex (MHC) gene, in regulating Epstein-Barr virus (EBV) infection of nasopharyngeal epithelial cells. We found that TRIM26 expression was induced upon EBV infection and that it indirectly targeted EphA2, a crucial epithelial receptor for EBV entry. Our results showed that TRIM26 interacted with heat shock protein 90-beta (HSP-90ß) and promoted its polyubiquitination, which led to its degradation via the proteasome pathway. This, in turn, affected EphA2 integrity and suppressed EBV infection. These findings suggest that TRIM26 could be a valuable target for developing therapeutic interventions against EBV infection and its associated pathogenesis.
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Infecções por Vírus Epstein-Barr , Humanos , Infecções por Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/fisiologia , Células Epiteliais/metabolismo , Ubiquitinação , Domínios Proteicos , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Claudin18.2 (CLDN18.2), due to its high expression in various gastric cancer tissues, is considered an optimal target for antitumor drug molecules. In this study, we obtained the labeled compounds of [125I]I-zolbetuximab using the Iodogen method. Under the optimum labeling conditions, the molar activity of [125I]I-zolbetuximab was 1.75 × 102 GBq/µmol, and the labeling efficiency was more than 99%. The labeled compounds exhibited excellent in vitro stability in both phosphate buffer saline (PBS, pH = 7.4) and fetal bovine serum systems (FBS) (radiochemical purity >90% at 72 h). The uptake percentage of [125I]I-zolbetuximab in MKN45-CLDN18.2 cells is 24.69 ± 0.84% after 6 h. The saturation binding assay and specificity assay further demonstrated the high specificity of [125I]I-zolbetuximab for CLDN18.2. The long retention at the tumor site and rapid metabolic clearance at other organ sites of [125I]I-zolbetuximab were observed in small-animal SPECT-CT imaging. The same trend was also observed in the biodistribution study. Due to the excellent targeting ability of zolbetuximab for CLDN18.2, [125I]I-zolbetuximab exhibits strong specific binding and retention with cells and tumors highly expressing CLDN18.2. However, the balance between mAb's longer cycle time in vivo and targeting binding and retention ability should be intensively considered for using this kind of radiopharmaceutical in the diagnosis and treatment of CLDN18.2-positive gastric cancer.
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Claudinas , Animais , Humanos , Camundongos , Distribuição Tecidual , Linhagem Celular Tumoral , Claudinas/metabolismo , Radioisótopos do Iodo , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/metabolismo , Compostos Radiofarmacêuticos/farmacocinética , Compostos Radiofarmacêuticos/química , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto , Camundongos Endogâmicos BALB C , Anticorpos Monoclonais/farmacocinética , Anticorpos Monoclonais/química , Feminino , Masculino , RatosRESUMO
MicroRNA detection is crucial for early infectious disease diagnosis and rapid cancer screening. However, conventional techniques like reverse transcription-quantitative polymerase chain reaction, requiring specialized training and intricate procedures, are less suitable for point-of-care analyses. To address this, we've developed a straightforward amplifier based on an exonuclease III (exo III)-propelled DNAzyme walker for sensitive and selective microRNA detection. This amplifier employs a specially designed hairpin probe with two exposed segments for strand recognition. Once the target microRNA is identified by the hairpin's extended single-strand DNA, exo III initiates its digestion, allowing microRNA regeneration and subsequent hairpin probe digestion cycles. This cyclical process produces a significant amount of DNAzyme, leading to a marked reduction in electrochemical signals. The biosensor exhibits a detection range from 10 fM to 100 pM and achieves a detection limit of 5 fM (3σ criterion). Importantly, by integrating an "And logic gate," our system gains the capacity for simultaneous diagnosis of multiple microRNAs, enhancing its applicability in RNA-based disease diagnostics.
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DNA Catalítico , Exodesoxirribonucleases , MicroRNAs , Amplificadores Eletrônicos , DNA de Cadeia SimplesRESUMO
Low quantum efficiency and serious photogenerated carrier recombination have been urgent bottleneck problems for photocatalytic materials. Herein, we prepared Nb, Se-codoped ZnIn2S4/NbSe2composites through a facile solvothermal method. The synergetic effect of codoping and cocatalyst was investigated on the photodegradation performance towards tetracycline under visible-light irradiation. By adjusting the final composition, the comprehensive characterization revealed that the optimum degradation efficiency of NS/ZIS-1.6 catalyst arrived at 75% in 70 min, which was 5.8 times higher than that of pure ZnIn2S4. Deep analysis indicated that the enhanced photocatalytic performance could be attributed to higher light absorption, more efficient electron/hole separation, faster charge transport, and lower carrier recombination. This work may offer novel viewpoint for design of high-performance catalysts towards the visible-light-driven photodegradation system.
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Emodin-8-O-ß-D-glucopyranoside (EG), a natural hydroxyanthraquinone glycoside from some traditional medicinal plants, has been demonstrated to have potential antitumor effects in our previous studies. Herein, we confirm that EG remains stable in the cell culture medium. It suppresses cell viability and proliferation and induces G1 cell cycle arrest in human colorectal cancer and neuroblastoma cells in vitro. EG inhibits tumor growth in human colorectal cancer cell HCT 116-bearing xenograft mice with low toxicity in the liver and kidney. The transcriptome analysis shows that the p53 signaling pathway is the most enriched cellular pathway and EG affects the proliferation of HCT 116 cells through modulating cell cycle related genes, such as CDKN1A and Cyclin-dependent kinases (CDKs). We demonstrate that the protein expression level of p21 was up-regulated, and CDK1/CDK2 were reduced significantly in both HCT 116 and SH-SY5Y cells after EG treatment. The switch from hypo- to hyper-phosphorylated Retinoblastoma (Rb), which is believed as a result of activated CDKs, was inhibited when cells were treated with EG. These findings indicate that EG suppresses cancer cell proliferation via p21-CDKs-Rb axis.
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Antraquinonas/farmacologia , Proliferação de Células/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Emodina/farmacologia , Glicosídeos/farmacologia , Proteína do Retinoblastoma/metabolismo , Animais , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Células HCT116 , Células HT29 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação/efeitos dos fármacos , Retinoblastoma/tratamento farmacológico , Retinoblastoma/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismoRESUMO
BACKGROUND: The pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis remains unknown. This study aimed to explore the pathogenesis of traumatic TMJ bony ankylosis in a rat model. METHODS: Twenty-four 3-week-old male Sprague-Dawley rats were used in this study. Excision of the whole disc, the fibrocartilage damage of the condyle and glenoid fossa, and narrowed joint space were performed in the left TMJ of the operation group to induce TMJ bony ankylosis (experimental side). The right TMJ underwent a sham operation (sham side). The control group did not undergo any operations. At 1, 4, and 8 weeks postoperatively, rats of the operation group were sacrificed and TMJ complexes were evaluated by gross observation, Micro-CT, histological examinations, and immunofluorescence microscopy. Total RNA of TMJ complexes in the operation group were analyzed using RNA-seq. RESULTS: Gross observations revealed TMJ bony ankylosis on the experimental side. Micro-CT analysis demonstrated that compared to the sham side, the experimental side showed a larger volume of growth, and a considerable calcified bone callus formation in the narrowed joint space and on the rougher articular surfaces. Histological examinations indicated that endochondral ossification was observed on the experimental side, but not on the sham side. RNA-seq analysis and immunofluorescence revealed that Matrix metallopeptidase 13 (MMP13) and Runt-related transcription factor 2 (RUNX2) genes of endochondral ossification were significantly more downregulated on the experimental side than on the sham side. The primary pathways related to endochondral ossification were Parathyroid hormone synthesis, secretion and action, Relaxin signaling pathway, and IL-17 signaling pathway. CONCLUSIONS: The present study provided an innovative and reliable rat model of TMJ bony ankylosis by compound trauma and narrowed joint space. Furthermore, we demonstrated the downregulation of MMP13 and RUNX2 in the process of endochondral ossification in TMJ bony ankylosis.
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Anquilose , Côndilo Mandibular , Masculino , Ratos , Animais , Côndilo Mandibular/diagnóstico por imagem , Côndilo Mandibular/lesões , Côndilo Mandibular/cirurgia , Ratos Sprague-Dawley , Anquilose/etiologia , Articulação TemporomandibularRESUMO
The Chinese jujube (Ziziphus jujuba Mill.), a member of the Rhamnaceae family, is an important perennial fruit tree crop of substantial economic, ecological and nutritional value, and is also used as a traditional herbal medicine. Here, we report the resequencing of 493 jujube accessions, including 202 wild and 291 cultivated accessions at >16× depth. Our population genomic analyses revealed that the Shanxi-Shaanxi area of China was jujube's primary domestication centre and that jujube was then disseminated into East China before finally extending into South China. Divergence events analysis indicated that Ziziphus acidojujuba and Ziziphus jujuba diverged around 2.7 Mya, suggesting the interesting possibility that a long pre-domestication period may have occurred prior to human intervention. Using the large genetic polymorphism data set, we identified a 15-bp tandem insertion in the promoter of the jujube ortholog of the POLLEN DEFECTIVE IN GUIDANCE 1 (POD1) gene, which was strongly associated with seed-setting rate. Integrating genome-wide association study (GWAS), transcriptome data, expression analysis and transgenic validation in tomato, we identified a DA3/UBIQUITIN-SPECIFIC PROTEASE 14 (UBP14) ortholog, which negatively regulate fruit weight in jujube. We also identified candidate genes, which have likely influenced the selection of fruit sweetness and crispness texture traits among fresh and dry jujubes. Our study not only illuminates the genetic basis of jujube evolution and domestication and provides a deep and rich genomic resource to facilitate both crop improvement and hypothesis-driven basic research, but also identifies multiple agriculturally important genes for this unique perennial tree fruit species.
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Ziziphus , China , Frutas/genética , Estudo de Associação Genômica Ampla , Genômica , Ziziphus/genéticaRESUMO
A general and efficient copper-catalyzed alkylation of silyl enol ethers with functionalized alkyl bromides has been developed for the synthesis of the sterically hindered γ-ketoesters. The transformation was induced through C(sp3)-halogen activation of commercially available sterically hindered alkyl bromides under mild conditions in good results. The strategy could be used for the synthesis of biologically active histamine H3 receptor (H3R) antagonist for medicinal purposes.
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Cobre , Éteres , Alquilação , Catálise , HistaminaRESUMO
OBJECTIVES: Odontogenic inflammatory diseases are main causes for alveolar bone breakdown and teeth loss, leaving great difficulties in denture restoration. Local inflammatory granulation tissue (IGT) is considered as pathological tissue and required to be removed. However, there are many evidences supporting that under appropriate intervention, IGT in alveolar bone maybe transformed into reparative granulation tissue (RGT), followed by ossification. Therefore, this study aimed to discover a specific target to promote this transformation. MATERIALS AND METHODS: After drawing out histological differences between IGT and RGT with haematoxylin and eosin (H&E) and immunohistochemical (IHC) assay staining, TMT-labelled quantitative proteomic analysis was applied to identify potential targets. RESULTS: The most striking histological property of RGT was found to be ECM deposition, which significantly decreased inflammatory cells, prominently increased fibroblasts as well as triggered changes of vascular types. Combined with histological findings and proteomic analysis, five KEGG pathways were associated with ECM, inflammation and angiogenesis and 49 pathways involved in differentially expressed proteins. COL1A1 was not only the most up-regulated protein, but also one of main hubs in protein-protein interaction regulatory network. Specific protease cathepsin K (CTSK) was identified. Level of CTSK in RGT was down-regulated to 69.10-76.97% (p < .05), with significantly up-regulated COL1A1, COL1A2, FN1 and TGFB1 included in focal adhesion, PI3K-Akt signalling pathways and angiogenesis. CTSK involved in transformation from IGT to RGT. CONCLUSIONS: CTSK might be a target to regulate transformation from IGT to RGT in alveolar bone through ECM, stem cells and angiogenesis mechanisms. However, further research is also clearly required.
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Fosfatidilinositol 3-Quinases , Proteômica , Tecido de Granulação , Humanos , Osteogênese , Células-TroncoRESUMO
BACKGROUND: Among several TF families unique to eukaryotes, the basic leucine zipper (bZIP) family is one of the most important. Chinese jujube (Ziziphus jujuba Mill.) is a popular fruit tree species in Asia, and its fruits are rich in sugar, vitamin C and so on. Analysis of the bZIP gene family of jujube has not yet been reported. In this study, ZjbZIPs were identified firstly, their expression patterns were further studied in different tissues and in response to various abiotic and phytoplasma stresses, and their protein-protein interactions were also analyzed. RESULTS: At the whole genome level, 45 ZjbZIPs were identified and classified into 14 classes. The members of each class of bZIP subfamily contain a specific conserved domain in addition to the core bZIP conserved domain, which may be related to its biological function. Relative Synonymous Codon Usage (RSCU) analysis displayed low values of NTA and NCG codons in ZjbZIPs, which would be beneficial to increase the protein production and also indicated that ZjbZIPs were at a relative high methylation level. The paralogous and orthologous events occurred during the evolutionary process of ZjbZIPs. Thirty-four ZjbZIPs were mapped to but not evenly distributed among 10 pseudo- chromosomes. 30 of ZjbZIP genes showed diverse tissue-specific expression in jujube and wild jujube trees, indicating that these genes may have multiple functions. Some ZjbZIP genes were specifically analyzed and found to play important roles in the early stage of fruit development. Moreover, some ZjbZIPs that respond to phytoplasma invasion and abiotic stress environmental conditions, such as salt and low temperature, were found. Based on homology comparisons, prediction analysis and yeast two-hybrid, a protein interaction network including 42 ZjbZIPs was constructed. CONCLUSIONS: The bioinformatics analyses of 45 ZjbZIPs were implemented systematically, and their expression profiles in jujube and wild jujube showed that many genes might play crucial roles during fruit ripening and in the response to phytoplasma and abiotic stresses. The protein interaction networks among ZjbZIPs could provide useful information for further functional studies.
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Fatores de Transcrição de Zíper de Leucina Básica/genética , Ziziphus/genética , Fatores de Transcrição de Zíper de Leucina Básica/isolamento & purificação , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Mapeamento Cromossômico , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla/métodos , Filogenia , Phytoplasma/metabolismo , Estresse Fisiológico/genética , Ziziphus/classificaçãoRESUMO
BACKGROUND: Bacillus licheniformis 2709 is extensively applied as a host for the high-level production of heterologous proteins, but Bacillus cells often possess unfavorable wild-type properties, such as production of viscous materials and foam during fermentation, which seriously influenced the application in industrial fermentation. How to develop it from a soil bacterium to a super-secreting cell factory harboring less undomesticated properties always plays vital role in industrial production. Besides, the optimal expression pattern of the inducible enzymes like alkaline protease has not been optimized by comparing the transcriptional efficiency of different plasmids and genomic integration sites in B. licheniformis. RESULT: Bacillus licheniformis 2709 was genetically modified by disrupting the native lchAC genes related to foaming and the eps cluster encoding the extracellular mucopolysaccharide via a markerless genome-editing method. We further optimized the expression of the alkaline protease gene (aprE) by screening the most efficient expression system among different modular plasmids and genomic loci. The results indicated that genomic expression of aprE was superior to plasmid expression and finally the transcriptional level of aprE greatly increased 1.67-fold through host optimization and chromosomal integration in the vicinity of the origin of replication, while the enzyme activity significantly improved 62.19% compared with the wild-type alkaline protease-producing strain B. licheniformis. CONCLUSION: We successfully engineered an AprE high-yielding strain free of undesirable properties and its fermentation traits could be applied to bulk-production by host genetic modification and expression optimization. In summary, host optimization is an enabling technology for improving enzyme production by eliminating the harmful traits of the host and optimizing expression patterns. We believe that these strategies can be applied to improve heterologous protein expression in other Bacillus species.
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Bacillus licheniformis/metabolismo , Proteínas de Bactérias/biossíntese , Endopeptidases/biossíntese , Bacillus licheniformis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fermentação , Engenharia Genética , Microbiologia Industrial , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Microrganismos Geneticamente Modificados/genética , Microrganismos Geneticamente Modificados/metabolismo , Plasmídeos/genéticaRESUMO
A novel aerobic oxidative Ugi-type multicomponent reaction (MCR) with tertiary amines was developed. The reaction was initiated by C(sp3)-H oxidation of the amine, followed by nucleophilic attack on the highly reactive isocyanide, generating nitrilium ion intermediates. If these intermediates were trapped by water in the system, α-amido amines could be delivered as the Ugi-3CR products. If exogenous TMSN3 was added, α-tetrazolo amines could be furnished as the first example of oxidative Ugi-azide MCR products.
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A simple and efficient Fe-catalyzed regioselective alkylation of 1,4-quinones and coumarins, using functionalized alkyl bromides as alkylating reagents, has been developed. The reaction proceeds under mild conditions with the addition of alkyl bromides to a wide range of 1,4-quinone and coumarin derivatives with a broad substrate scope and wide functional group tolerance to provide the products in good yields. Further application of these strategies could be extended to important biologically active antimalarial lead drugs, such as plasmodione on a gram scale in a single step for medicinal purposes.
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Cancer metastasis is the primary cause of death in patients diagnosed with colorectal cancer. Piperine, an active nontoxic ingredient in pepper, has potent anti-inflammatory and anti-cancer properties. However, little is known about the anti-migratory and anti-invasive effects of piperine on colorectal cancer. We demonstrated piperine inhibited the migration and invasion of colorectal cancer cells. Then, we found piperine reversed the biomarker expression of epithelial-to-mesenchymal transition (EMT), and suppressed the EMT regulator Snail. Furthermore, signal transducers and activators of transcription 3 (STAT3) was downregulated by piperine. Finally, STAT3 inhibitors were applied to observe the role of STAT3 in colorectal cancer migration, invasion and EMT. Collectively, piperine inhibits colorectal cancer migratory and invasive capacities through STAT3/Snail mediated EMT. Therefore, piperine could be applied as a possible therapeutic regimen for the prevention of colorectal cancer metastasis.
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Alcaloides/farmacologia , Benzodioxóis/farmacologia , Neoplasias Colorretais/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Piperidinas/farmacologia , Alcamidas Poli-Insaturadas/farmacologia , Fator de Transcrição STAT3/metabolismo , Fatores de Transcrição da Família Snail/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , HumanosRESUMO
BACKGROUND: This study aimed to compare the operative outcome of percutaneous repair (modified Bunnell suture technique) versus open repair (bundle-to-bundle suture technique) of acute Achilles tendon rupture. METHODS: Seventy-two consecutive patients who underwent surgical treatment of Achilles tendon rupture were evaluated in this prospective study. Thirty-six patients were treated using the bundle-to-bundle suture technique (group A), and 36 patients were treated using the modified Bunnell suture technique (group B). All patients underwent functional examination comprising measurement of the calf muscle circumference and performance of the single-leg heel-rise test. The length and diameter of the Achilles tendon were compared between the injured and uninjured sides on magnetic resonance imaging. The number of single-leg heel rises (height > 5 cm) performed within 15 s was compared between the injured and uninjured sides. The ankle range of motion was also recorded. The Achilles tendon total rupture score (ATRS), American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale score, and visual analog scale (VAS) pain score were used to evaluate the clinical outcome at 12 months postoperatively. RESULTS: A total of 61 patients were followed up. The mean follow-up duration did not significantly differ between group A (23.73 ± 2.81 months) and group B (22.61 ± 3.96 months). However, there were significant differences between groups in the heel-rise test (group A, 1.74 ± 0.96; group B, 2.37 ± 1.42) and length of the Achilles tendon (group A, 11.98 ± 1.64 cm; group B, 11.11 ± 1.74 cm). The calf circumference of the injured side was significantly larger in group A than in group B (p = 0.043). The cross-sectional diameter of the Achilles tendon was significantly smaller in group A than group B. At final follow-up, there were no significant differences between the two groups in the ATRS, AOFAS score, or VAS score. One patient in group A had delayed wound healing, which resolved in 40 days. CONCLUSIONS: Patients with acute Achilles tendon rupture treated with open repair (bundle-to-bundle suture technique) achieved a better clinical outcome regarding the heel-rise test and calf circumference compared with those treated with percutaneous repair (modified Bunnell suture technique). TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000035229 , 8/4/2020, Retrospectively registered.
Assuntos
Tendão do Calcâneo , Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/cirurgia , Idoso , Estudos Transversais , Humanos , Estudos Prospectivos , Ruptura/diagnóstico por imagem , Ruptura/cirurgia , Técnicas de Sutura , Suturas , Resultado do TratamentoRESUMO
BACKGROUND: Casticin, an isoflavone compound extracted from the herb Fructus Viticis, has demonstrated anti-inflammatory and anticancer activities and properties. The aim of this study was to investigate the effects and mechanisms of casticin in nasopharyngeal carcinoma (NPC) cells and to determine its potential for targeted use as a medicine. METHODS: NPC cells were used to perform the experiments. The CCK8 assay and colony formation assays were used to assess cell viability. Flow cytometry was used to measure the cell cycle and apoptosis analysis (annexin V/PI assay). A three-dimensional (3D) tumour sphere culture system was used to characterize the effect of casticin on NPC stem cells. In silico molecular docking prediction and high-throughput KINOME scan assays were used to evaluate the binding of casticin to phosphoinositide 3-kinase (PI3K), including wild-type and most of mutants variants. We also used the SelectScreen assay to detect the IC50 of ATP activity in the active site of the target kinase. Western blotting was used to evaluate the changes in key proteins involved cell cycle, apoptosis, stemness, and PI3K/protein kinase B (AKT) signalling. The effect of casticin treatment in vivo was determined by using a xenograft mouse model. RESULTS: Our results indicate that casticin is a new and novel selective PI3K inhibitor that can significantly inhibit NPC proliferation and that it induces G2/GM arrest and apoptosis by upregulating Bax/BCL2 expression. Moreover, casticin was observed to affect the self-renewal ability of the nasopharyngeal carcinoma cell lines, and a combination of casticin with BYL719 was observed to induce a decrease in the level of the phosphorylation of mTORC1 downstream targets in BYL719-insensitive NPC cell lines. CONCLUSION: Casticin is a newly emerging selective PI3K inhibitor with potential for use as a targeted therapeutic treatment for nasopharyngeal carcinoma. Accordingly, casticin might represent a novel and effective agent against NPC and likely has high potential for combined use with pharmacological agents targeting PI3K/AKT.
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A method for the synthesis of 2-thiolated benzimidazoles is described starting from thiols and 1-azido-2-isocyanoarenes. The isocyano group works as an acceptor of various thio radicals, followed by denitrogenative annulation of the resulting imidoyl radical intermediates to the azido group, with nitrogen loss as the only process involving high bond-forming efficiency. The one-pot method for the synthesis of these products with high functional group tolerance in the benzimidazole-based ring is not available in previous literature.
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To promote enzymatic unhairing for leather production, a new unhairing enzyme is developed. The Keratinase (kerT) gene, which is amplified from B. amyloliquefaciens TCCC11319 by PCR, is expressed in B. subtilis WB600. The recombinant KerT reduces the collagenolytic protease content as well as improving the keratinase content effectively. Therefore, the improved keratinase leads to the obviously unhairing effect, whereas the low collagenolytic protease ensures the integrity of collagen fibers in hide. It represents, the leather grain surface isn't destroyed thereby the value of finished leather can be maintained. In addition, by analyzing the properties of KerT, tits activity isn't inhibited with Na+, K+ and Ca2+ which are commonly used in leather production. The freeze-dried fermentation broth can be used directly as unhairing enzyme without addition of traditional sulfide chemicals. By evaluating the properties of unhaired hide, the results show that the collagen degradation ability of this new unhairing enzyme is slightly and it does not cause any adverse effects on the leather quality. Besides, this unhairing enzyme doesn't further degrade collagen in the time range of 8 h to 24 h, thus it is safely and easy-control in actual production. In conclusion, the enzymatic unhairing method with recombinant KerT has the potential to be more sustainable and efficient alternative than current sulphur-lime method, and it does not require the further purification thereby saving the cost.
Assuntos
Bacillus subtilis/enzimologia , Bacillus subtilis/genética , DNA Bacteriano/isolamento & purificação , Peptídeo Hidrolases/genética , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Fragmentação do DNA , DNA Bacteriano/genética , Fermentação , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Peptídeo Hidrolases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
A Cu-catalyzed regioselective bromodifluoroacetylation of alkenes, using ethyl bromodifluoroacetate (BrCF2CO2Et) as a difluoroacetylating reagent, has been disclosed. The reaction proceeds under mild conditions, and possible byproducts generated from hydrodifluoroacetylation and/or direct alkenyl C-H difluoroacetylation are not observed. Mechanistic studies confirm that the atom transfer radical addition (ATRA) process is involved in this alkene difunctionalization reaction.
RESUMO
A palladium-catalyzed double isocyanide insertion using 2-iodo-2'-isocyano-1,1'-biphenyls followed by copper-catalyzed intramolecular C-N coupling, delivering a unique heterocyclic structure containing both phenanthridine and carbazole scaffolds, has been developed. In this cascade process, four chemical bonds, including two C-C, one C-O, and one C-N bonds are formed consecutively without isolating an intermediate. The strategy of using a functionalized isocyanide in double insertion provides a quick approach for constructing heterocyclic systems with high bond-forming efficiency.