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The mechanism that maintains ER-to-Golgi vesicles formation and transport is complicated. As one of the adapters, Ninein-like protein (Nlp) participated in assembly and transporting of partial ER-to-Golgi vesicles that contained specific proteins, such as ß-Catenin and STING. Nlp acted as a platform to sustain the specificity and continuity of cargoes during COPII and COPI-coated vesicle transition and transportation through binding directly with SEC31A as well as Rab1B. Thus, we proposed an integrated transport model that particular adapter participated in specific cargo selection or transportation through cooperating with different membrane associated proteins to ensure the continuity of cargo trafficking. Deficiency of Nlp led to vesicle budding failure and accumulation of unprocessed proteins in ER, which further caused ER stress as well as Golgi fragmentation, and PERK-eIF2α pathway of UPR was activated to reduce the synthesis of universal proteins. In contrast, upregulation of Nlp resulted in Golgi fragmentation, which enhanced the cargo transport efficiency between ER and Golgi. Moreover, Nlp deficient mice were prone to spontaneous B cell lymphoma, since the developments and functions of lymphocytes significantly depended on secretory proteins through ER-to-Golgi vesicle trafficking, including IL-13, IL-17 and IL-21. Thus, perturbations of Nlp altered ER-to-Golgi communication and cellular homeostasis, and might contribute to the pathogenesis of B cell lymphoma.
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Retículo Endoplasmático , Complexo de Golgi , Animais , Humanos , Camundongos , Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Transporte ProteicoRESUMO
BACKGROUND: Prostate cancer (PCa) is one of the most common malignancies in men. PCa is difficult to detect in its early stages, and most patients are diagnosed in the middle to late stages. At present, drug therapy for advanced PCa is still insufficient. Some patients develop drug resistance in the later stage of therapy, which leads to tumor recurrence, metastasis and even treatment failure. Therefore, it is crucial to find new and effective drugs to treat prostate cancer. OBJECTIVE: The aim of this study was to investigate the anti-cancer effect of salidroside, an active ingredient in a traditional Chinese herbal medicine, on PCa. METHODS: Two human PCa cell lines, PC3 and DU145, were cultured and treated with salidroside. Cell viability and proliferation ability were analyzed through CCK-8 and colony assays, and cell migration ability was detected by Transwell and Scratch assays. RT-PCR and WB were used to detected the expression levels of moleculars related to cell proliferation, apoptosis, migration, and AKT signaling pathway. Forthmore, we performed rescue experiments with agonist to verify the affected signaling pathway. RESULTS: Salidroside inhibited the proliferation, colony formation, and migration of PCa cells. Meanwhile, apoptosis of PCa cells was enhanced. Moreover, salidroside inhibited PI3K/AKT pathway in PCa cells. The treatment of AKT agonist 740Y-P abrogated the inhibitory effect of salidroside on the PI3K/AKT signaling pathway. CONCLUSIONS: Our study demonstrated that in PCa cells, salidroside inhibites proliferation and migration and promots apoptosis via inhibiting PI3K/AKT pathway.
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Fosfatidilinositol 3-Quinases , Neoplasias da Próstata , Masculino , Humanos , Proteínas Proto-Oncogênicas c-akt , Recidiva Local de Neoplasia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Proliferação de CélulasRESUMO
Background Pathological cardiac hypertrophy is a major cause of heart failure morbidity. The complex mechanism of intermolecular interactions underlying the pathogenesis of cardiac hypertrophy has led to a lack of development and application of therapeutic methods. Methods and Results Our study provides the first evidence that TRAF4, a member of the tumor necrosis factor receptor-associated factor (TRAF) family, acts as a promoter of cardiac hypertrophy. Here, Western blotting assays demonstrated that TRAF4 is upregulated in cardiac hypertrophy. Additionally, TRAF4 deletion inhibits the development of cardiac hypertrophy in a mouse model after transverse aortic constriction surgery, whereas its overexpression promotes phenylephrine stimulation-induced cardiomyocyte hypertrophy in primary neonatal rat cardiomyocytes. Mechanistically, RNA-seq analysis revealed that TRAF4 promoted the activation of the protein kinase B pathway during cardiac hypertrophy. Moreover, we found that inhibition of protein kinase B phosphorylation rescued the aggravated cardiomyocyte hypertrophic phenotypes caused by TRAF4 overexpression in phenylephrine-treated neonatal rat cardiomyocytes, suggesting that TRAF4 may regulate cardiac hypertrophy in a protein kinase B-dependent manner. Conclusions Our results revealed the regulatory function of TRAF4 in cardiac hypertrophy, which may provide new insights into developing therapeutic and preventive targets for this disease.
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Insuficiência Cardíaca , Proteínas Proto-Oncogênicas c-akt , Camundongos , Animais , Ratos , Fator 4 Associado a Receptor de TNF , Fenilefrina/farmacologia , CardiomegaliaRESUMO
Background: Hepatocellular carcinoma (HCC) is one of the most malignant cancers in the world, and its 5- year survival rate is low. At present, for advanced primary liver cancer, the clinical treatment often adopts the systemic method, but there is no effective targeted treatment. The average survival time of patients with liver cancer after drug treatment is only 3-5 months. Therefore, it is of great clinical significance to find new and effective drugs for the treatment of HCC. Carnosol (CA) is a bioactive diterpene compound present in Lamiaceae spp., which has been demonstrated to have antioxidant, anti-inflammatory, and anticancer properties. Aim: In this study, we aimed to reveal the effect of carnosol on HCC and provide new possibilities for the drug therapy of HCC. Obejective: The objective of this study is to observe the effect of carnosol on the tumor phenotype and signaling pathway of HCC cells. Methods: We treated two different human HCC cells, HepG2 and Huh7, with carnosol. The cells were analyzed using the CCK-8 assay for viability and proliferation. The cell migration and invasion were detected by Transwell assay. The molecular markers of cell proliferation, apoptosis, migration, invasion, and signaling pathways were detected by RTPCR and WB. In addition, we performed rescue experiments with inhibitors to verify the affected signaling pathway. Results: The results showed that carnosol could significantly inhibit HCC cell viability, effort, colony formation, migration, and invasion. Moreover, Carnosol promoted the apoptosis of HCC cells. Mechanically, carnosol activated the AMPK-p53 pathway. Conclusion: To conclude, our study demonstrated that carnosol could inhibit proliferation, migration, invasion, and promote apoptosis via activating AMPK-p53 in HCC cells.
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Metabolic reprogramming plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the key drivers of metabolic reprogramming underlying HCC progression remain unclear. Using a large-scale transcriptomic database and survival correlation screening, we identify thymidine kinase 1 (TK1) as a key driver. The progression of HCC is robustly mitigated by TK1 knockdown and significantly aggravated by its overexpression. Furthermore, TK1 promotes the oncogenic phenotypes of HCC not only through its enzymatic activity and production of deoxythymidine monophosphate (dTMP) but also by promoting glycolysis via binding with protein arginine methyltransferase 1 (PRMT1). Mechanistically, TK1 directly binds PRMT1 and stabilizes it by interrupting its interactions with tripartite-motif-containing 48 (TRIM48), which inhibits its ubiquitination-mediated degradation. Subsequently, we validate the therapeutic capacity of hepatic TK1 knockdown in a chemically induced HCC mouse model. Therefore, targeting both the enzyme-dependent and -independent activity of TK1 may be therapeutically promising for HCC treatment.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Camundongos , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Timidina Quinase/genética , Timidina Quinase/metabolismo , Ubiquitinação , Linhagem Celular TumoralRESUMO
BACKGROUND: Carnosol is a phytopolyphenol (diterpene) found and extracted from plants of Mediterranean diet, which has anti-tumor, anti-inflammatory and antioxidant effects. However, its role in ischemic stroke has not been elucidated. METHODS: Primary neurons subjected to oxygen-glucose deprivation (OGD) was used to investigate the effect of carnosol in vitro. A mouse MCAO model was used to evaluate the effect of carnosol on ischemic stroke in vivo. The mRNA level of inflammatory and apoptosis-related genes was determined by RT-PCR. The protein level of total and phosphorylated AMPK was determined by WB. H&E and Immunofluorescent assay was used to investigate the necrosis, inflammation and apoptosis in brain tissue. RESULTS: Carnosol protected the activity of primary neurons subjected to oxygen-glucose deprivation (OGD) in vitro, as well as inhibited inflammation and apoptosis. Furthermore, carnosol could significantly reduce the infarct and edema volume and protect against neurological deficit in vivo, and had a significant inhibitory effect on brain neuroinflammation and apoptosis. Mechanically, carnosol could activate AMPK, and the effect of carnosol on cerebral ischemia-reperfusion injury cell model could be abolished by AMPK phosphorylation inhibitor. CONCLUSION: Carnosol has a protective effect on ischemic stroke, and this effect is achieved through AMPK activation. Our study demonstrates the protective effect of carnosol on cerebral ischemia-reperfusion injury and provides a new perspective for the clinical treatment of ischemic stroke.
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Isquemia Encefálica , AVC Isquêmico , Traumatismo por Reperfusão , Acidente Vascular Cerebral , Camundongos , Animais , Acidente Vascular Cerebral/metabolismo , Proteínas Quinases Ativadas por AMP , Isquemia Encefálica/metabolismo , Inflamação/tratamento farmacológico , Anti-Inflamatórios/farmacologia , AVC Isquêmico/tratamento farmacológico , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Glucose/metabolismo , Oxigênio/farmacologia , Apoptose , Infarto da Artéria Cerebral Média/tratamento farmacológicoRESUMO
Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by excessive deposition of fatty acids in the liver. Further deterioration leads to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma, creating a heavy burden on human health and the social economy. Currently, there are no effective and specific drugs for the treatment of NAFLD. Therefore, it is important to further investigate the pathogenesis of NAFLD and explore effective therapeutic targets for the prevention and treatment of the disease. Six-transmembrane epithelial antigen of prostate 3 (STEAP3), a STEAP family protein, is a metalloreductase. Studies have shown that it can participate in the regulation of liver ischemia-reperfusion injury, hepatocellular carcinoma, myocardial hypertrophy, and other diseases. In this study, we found that the expression of STEAP3 is upregulated in NAFLD. Deletion of STEAP3 inhibits the development of NAFLD in vivo and in vitro, whereas its overexpression promotes palmitic acid/oleic acid stimulation-induced lipid deposition in hepatocytes. Mechanistically, it interacts with transforming growth factor beta-activated kinase 1 (TAK1) to regulate the progression of NAFLD by promoting TAK1 phosphorylation and activating the TAK1-c-Jun N-terminal kinase/p38 signaling pathway. Taken together, our results provide further insight into the involvement of STEAP3 in liver pathology.
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Carcinoma Hepatocelular , Resistência à Insulina , Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Humanos , Masculino , Carcinoma Hepatocelular/patologia , Hepatócitos/metabolismo , Fígado/metabolismo , Neoplasias Hepáticas/patologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Próstata/metabolismoRESUMO
Ring-finger protein 5 (RNF5) is an E3 ubiquitin ligase which is expressed in a variety of human tissues. RNF5 is involved in the regulation of endoplasmic reticulum stress, inflammation, and innate immunity and plays an important role in the occurrence and development of various tumors. However, the role of RNF5 in cardiac hypertrophy has not been reported. In this study, we found the expression of RNF5 was increased in the hearts of mice with pathological cardiac hypertrophy. The loss-of-function research demonstrated that RNF5 deficiency exacerbated cardiac hypertrophy, whereas gain-of-function studies revealed that overexpression of RNF5 had opposite effects. The stimulator of interferon genes (STING) is a signaling molecule that can activate type I interferon immunity, which can meditate inflammation and immune response in many diseases. The protein-protein interaction experiments confirmed that STING interacted with RNF5. Further studies showed that RNF5 inhibited cardiac hypertrophy by promoting STING degradation through K48-linked polyubiquitination. Therefore, we defined RNF5 as importantly regulated signaling for cardiac hypertrophy.
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Interferon Tipo I , Ubiquitina-Proteína Ligases , Animais , Humanos , Camundongos , Cardiomegalia/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Inflamação , Interferon Tipo I/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Autophagy is the main degradation pathway to eliminate long-lived and aggregated proteins, aged or malfunctioning organelles, which is essential for the intracellular homeostasis and prevention of malignant transformation. Although the processes of autophagosome biogenesis have been well illuminated, the mechanism of autophagosome transport remains largely unclear. In this study, we demonstrated that the ninein-like protein (Nlp), a well-characterized centrosomal associated protein, was able to modulate autophagosome transport and facilitate autophagy. During autophagy, Nlp colocalized with autophagosomes and physically interacted with autophagosome marker LC3, autophagosome sorting protein Rab7 and its downstream effector FYCO1. Interestingly, Nlp enhanced the interaction between Rab7 and FYCO1, thus accelerated autophagic flux and the formation of autophagolysosomes. Furthermore, compared to the wild-type mice, NLP deficient mice treated with chemical agent DMBA were prone to increased incidence of hepatomegaly and liver cancer, which were tight associated with the hepatic autophagic defect. Taken together, our findings provide a new insight for the first time that the well-known centrosomal protein Nlp is also a new regulator of autophagy, which promotes the interaction of Rab7 and FYCO1 and facilitates the formation of autophagolysosome.
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Autofagia/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas Nucleares/genética , proteínas de unión al GTP Rab7/genética , Animais , Antracenos/farmacologia , Autofagossomos/genética , Centrossomo/metabolismo , Hepatomegalia/genética , Humanos , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Camundongos , Piperidinas/farmacologiaRESUMO
Alzheimer's disease (AD) is a neurodegenerative disease characterized by decreased glucose metabolism and increased neuroinflammation. Hexokinase (HK) is the key enzyme of glucose metabolism and is associated with mitochondria to exert its function. Recent studies have demonstrated that the dissociation of HK from mitochondria is enough to activate the NOD-like receptor protein 3 (NLRP3) inflammasome and leads to the release of interleukin-1ß (IL-1ß). However, the effect of increased IL-1ß on the expression of HK is still unclear in AD. In this paper, we used positron emission tomography (PET), Western blotting and immunofluorescence to study the glucose metabolism, and the expression and distribution of HK in AD. Furthermore, we used lipopolysaccharide (LPS), nigericin (Nig), CY-09 and lonidamine (LND) to treat N2a and N2a-sw cells to investigate the link between IL-1ß and HK in AD. The results show decreased expression of HK and the dissociation of HK from mitochondria in AD. Furthermore, a reduction of the expression of IL-1ß could increase the expression of HK in AD. These results suggest that inhibiting inflammation may help to restore glucose metabolism in AD.
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Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Hexoquinase/metabolismo , Interleucina-1beta/metabolismo , Doença de Alzheimer/genética , Animais , Linhagem Celular , Modelos Animais de Doenças , Feminino , Hexoquinase/genética , Humanos , Indazóis/farmacologia , Interleucina-1beta/genética , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Transgênicos , Nigericina/farmacologia , Tomografia por Emissão de Pósitrons , Tiazolidinas/farmacologia , Tionas/farmacologia , Regulação para CimaRESUMO
Numerous studies have shown that over-nutritional obesity may lead to pre-diabetes, type 2 diabetes and cognitive decline. As the degree of metabolic disorders increases, the cognitive decline is getting worse. However, the cellular events that cause this cognitive dysfunction is yet to be clarified. We used a high-fat diet (HFD) consumption-induced obesity mouse model to test the effects of metformin on the hippocampal neurogenesis and learning and memory abilities of obese mice. 5-Bromo-2'-deoxyuridine (BrdU) labelling and retrovirus labeling were applied to detect hippocampal newborn neurons. Behavioral experiments were used to detect learning and memory abilities of mice. 16S rRNA gene sequencing was performed to detect the composition of gut microbiota. The positron emission tomography (PET) was conducted to detect the energy metabolism activity of different mouse brain regions. Our results reveal that metformin restores the impairment of neurogenesis in the dentate gyrus and finally prevents the cognitive decline of the obese mice. Moreover, the therapeutic effects of metformin are achieved by regulating the composition of gut microbiota of mice, which may inhibit microglia activation and neuroinflammation in the brain of obese mice. This study suggests that metformin may be taken as a promising candidate for the intervention of cognitive decline related to imbalance of gut microbiota caused by obesity.
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Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Metformina , Animais , Dieta Hiperlipídica , Hipocampo , Metformina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Neurogênese , Obesidade/tratamento farmacológico , RNA Ribossômico 16SRESUMO
Chronic sleep insufficiency is becoming a common issue in the young population nowadays, mostly due to life habits and work stress. Studies in animal models of neurological diseases reported that it would accelerate neurodegeneration progression and exacerbate interstitial metabolic waste accumulation in the brain. In this paper, we study whether chronic sleep insufficiency leads to neurodegenerative diseases in young wild-type animals without a genetic pre-disposition. To this aim, we modeled chronic sleep fragmentation (SF) in young wild-type mice. We detected pathological hyperphosphorylated-tau (Ser396/Tau5) and gliosis in the SF hippocampus. 18F-labeled fluorodeoxyglucose positron emission tomography scan (18F-FDG-PET) further revealed a significant increase in brain glucose metabolism, especially in the hypothalamus, hippocampus and amygdala. Hippocampal RNAseq indicated that immunological and inflammatory pathways were significantly altered in 1.5-month SF mice. More interestingly, differential expression gene lists from stress mouse models showed differential expression patterns between 1.5-month SF and control mice, while Alzheimer's disease, normal aging, and APOEε4 mutation mouse models did not exhibit any significant pattern. In summary, 1.5-month sleep fragmentation could generate AD-like pathological changes including tauopathy and gliosis, mainly linked to stress, as the incremented glucose metabolism observed with PET imaging suggested. Further investigation will show whether SF could eventually lead to chronic neurodegeneration if the stress condition is prolonged in time.
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Esophageal squamous cell carcinoma (ESCC) is one of the most common and deadly diseases. In our previous comprehensive genomics study, we found that family with sequence similarity 135 member B (FAM135B) was a novel cancer-related gene, yet its biological functions and molecular mechanisms remain unclear. In this study, we demonstrate that the protein levels of FAM135B are significantly higher in ESCC tissues than in precancerous tissues, and high expression of FAM135B correlates with poorer clinical prognosis. Ectopic expression of FAM135B promoted ESCC cell proliferation in vitro and in vivo, likely through its direct interaction with growth factor GRN, thus forming a feedforward loop with AKT/mTOR signaling. Patients with ESCC with overexpression of both FAM135B and GRN had worse prognosis; multivariate Cox model analysis indicated that high expression of both FAM135B and GRN was an independent prognostic factor for patients with ESCC. FAM135B transgenic mice bore heavier tumor burden than wild-type mice and survived a relatively shorter lifespan after 4-nitroquinoline 1-oxide treatment. In addition, serum level of GRN in transgenic mice was higher than in wild-type mice, suggesting that serum GRN levels might provide diagnostic discrimination for patients with ESCC. These findings suggest that the interaction between FAM135B and GRN plays critical roles in the regulation of ESCC progression and both FAM135B and GRN might be potential therapeutic targets and prognostic factors in ESCC. SIGNIFICANCE: These findings investigate the mechanisms of FAM135B in promoting ESCC progression and suggest new potential prognostic biomarkers and therapeutic targets in patients with ESCC.
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Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Progranulinas/fisiologia , Animais , Comunicação Autócrina/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Progressão da Doença , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/mortalidade , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo , Carcinoma de Células Escamosas do Esôfago/mortalidade , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Camundongos Transgênicos , Prognóstico , Progranulinas/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/metabolismoRESUMO
BACKGROUND: The prognosis for esophageal squamous cell carcinoma (ESCC) patients with lymph node metastasis (LNM) is still dismal. Elucidation of the LNM associated genomic alteration and underlying molecular mechanisms may provide clinical therapeutic strategies for ESCC treatment. METHODS: Joint analysis of ESCC sequencing data were conducted to comprehensively survey SCNAs and identify driver genes which significantly associated with LNM. The roles of miR-548k in lymphangiogensis and lymphatic metastasis were validated both in vitro and in vivo. ESCC tissue and blood samples were analyzed for association between miR-548k expression and patient clinicopathological features and prognosis and diagnosis. RESULTS: In the pooled cohort of 314 ESCC patients, we found 76 significant focused regions including 43 amplifications and 33 deletions. Clinical implication analysis revealed a panel of genes associated with LNM with the most frequently amplified gene being MIR548K harbored in the 11q13.3 amplicon. Overexpression of miR-548k remarkably promotes lymphangiogenesis and lymphatic metastasis in vitro and in vivo. Furthermore, we demonstrated that miR-548k modulating the tumor microenvironment by promoting VEGFC secretion and stimulating lymphangiogenesis through ADAMTS1/VEGFC/VEGFR3 pathways, while promoting metastasis by regulating KLF10/EGFR axis. Importantly, we found that serum miR-548k and VEGFC of early stage ESCC patients were significantly higher than that in healthy donators, suggesting a promising application of miR-548k and VEGFC as biomarkers in early diagnosis of ESCC. CONCLUSIONS: Our study comprehensively characterized SCNAs in ESCC and highlighted the crucial role of miR-548k in promoting lymphatic metastasis, which might be employed as a new diagnostic and prognostic marker for ESCC.
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Cromossomos Humanos Par 11/genética , Neoplasias Esofágicas/metabolismo , Carcinoma de Células Escamosas do Esôfago/patologia , Amplificação de Genes , Metástase Linfática/genética , MicroRNAs/genética , Animais , Linhagem Celular Tumoral , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo , Feminino , Humanos , Masculino , Camundongos , Transplante de Neoplasias , Prognóstico , Análise de Sequência de RNA , Microambiente Tumoral , Fator C de Crescimento do Endotélio Vascular/metabolismoRESUMO
The role of conformational flexibility in topological enforcement of several crystalline materials based on hydrogen-bonded two-dimensional guanidinium-sulfonate (GS) networks is demonstrated by using a series of organopolysulfonates that prompt the formation of either lamellar or cylindrical architectures. Whereas flexible organopolysulfonate linkers decorated with flexible arms self-assemble into lamellar architectures, rigid organopolysulfonates linkers enforce the formation of hydrogen-bonded cylinders with intercylinder spacing governed by the size of the linker. Specifically, hexagonal cylindrical structures generated from trisulfonates with three-fold molecular symmetry are the topological equivalent of the cylindrical hexagonal phases reported previously for guanidinium organomonosulfonate inclusion compounds, but neighboring cylinders are now connected through covalent nodes provided by the trisulfonates rather than dispersive interactions between the arene rings of the organomonosulfonates. Organopolysulfonates with moderate conformational freedom, however, can generate both lamellar and cylindrical structures, depending on the guest molecules encapsulated by the host framework. These observations illustrate that the crystal architecture (i.e., lamellar vs cylindrical) and the shape of GS cylinders can be regulated in a predictable way by the molecular symmetries and conformational constraints of the organopolysulfonates building blocks.
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Ligação de Hidrogênio , Benzenossulfonatos/química , Cristalografia por Raios X , Guanidina/química , Modelos Moleculares , Conformação MolecularRESUMO
A molecular framework based on guanidinium cations and 1,2,4,5-tetra(4-sulfonatophenyl)benzene (TSPB), an aromatic tetrasulfonate with nominal 2-fold and mirror symmetry, exhibits three crystallographically unique one-dimensional channels as a consequence of molecular symmetry and complementary hydrogen bonding between the guanidinium (G) ions and the sulfonate (S) groups of TSPB. Unlike previous GS frameworks, this new topology is sufficiently flexible to permit reversible release and adsorption of guest molecules in large single crystals through a cyclic shrinkage and expansion of the channels with retention of single crystallinity, as verified by single crystal X-ray diffraction. Moreover, the G4TSPB framework permits guest exchange between various guest molecules through SCSCTs as well as exchange discrimination based on the size and character of the three different channels. The exchange of guest molecules during single crystal-single crystal transformations (SCSCT), a rare occurrence for hydrogen-bonded frameworks, is rather fast, with diffusivities of approximately 10(-6) cm(2) s(-1). Rapid diffusion in the two channels having cross sections sufficient to accommodate two guest molecules can be explained by two-way or ring diffusion, most likely vacancy assisted. Surprisingly, rapid guest exchange also is observed in a smaller channel having a cross-section that accommodates only one guest molecule, which can only be explained by guest-assisted single-file unidirectional diffusion. Several single crystals of inclusion compounds can be realized only through guest exchange in the intact framework, suggesting an approach to the synthesis of single crystalline inclusion compounds that otherwise cannot be attained through direct crystallization methods.
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We describe a facile low-temperature physical vapor deposition approach to fabricate porous network thin films constructed of nanowires of small organic molecules on a large area. Supermolecular assemblies of pyrene nanowires based on a combination of van der Waals forces and pi-pi stacking tend to hierarchically self-assemble to form uniform porous films using our techniques. The morphology of the films is studied and we also study several reasons influencing the process of assembly such as evaporation temperature, deposition temperature, and different kinds of substrate. The deposition temperature is determined to be the main reason for hierarchical aggregation. Typically prepared films exhibit unique optical properties, that is, multicolor red-green-blue emissions. This novel method can be applied to other organic molecular systems and may be potentially used to place nanoscaled building blocks directly on solid surfaces for fabricating large-area nanostructure-based flat screens.