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1.
Clin Transl Oncol ; 26(2): 363-374, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38103120

RESUMO

INTRODUCTION: The critical role of microRNA-128 (miR-128) in gastrointestinal-related diseases has been documented. In the current study, we tried to clarify the specific role miR-128 in gastrointestinal stromal tumor (GIST) and the underlying mechanism. METHODS: Differentially expressed genes in GIST were identified following bioinformatics analysis. Then, expression patterns of miR-128 and B-lymphoma Mo-MLV insertion region 1 (BMI-1) in clinical tissue samples and cell lines were characterized, followed by validation of their correlation. GIST-T1 cells were selected and transfected with different mimic, inhibitor, or siRNA plasmids, after which the biological functions were assayed. RESULTS: We identified low miR-128 and high BMI-1 expression in GIST tissues of 78 patients and 4 GIST cell lines. Ectopic expression of miR-128 or silencing of BMI-1 suppressed the malignant potentials of GIST-T1 cells. As a target of miR-128, BMI-1 re-expression could partly counteract the suppressive effect of miR-128 on the malignancy of GIST-T1 cells. CONCLUSION: Our study provided evidence that miR-128-mediated silencing of BMI-1 could prevent malignant progression of GIST, highlighting a promising anti-tumor target for combating GIST.


Assuntos
Tumores do Estroma Gastrointestinal , Linfoma , MicroRNAs , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Tumores do Estroma Gastrointestinal/genética , Tumores do Estroma Gastrointestinal/patologia , Proliferação de Células , RNA Interferente Pequeno/farmacologia , Linhagem Celular Tumoral , Apoptose
2.
Angew Chem Int Ed Engl ; 62(40): e202311352, 2023 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-37592375

RESUMO

A few-layer fullerene network possesses several advantageous characteristics, including a large surface area, abundant active sites, high charge mobility, and an appropriate band gap and band edge for solar water splitting. Herein, we report for the first time that the few-layer fullerene network shows interesting photocatalytic performance in pure water splitting into H2 and H2 O2 in the absence of any sacrificial reagents. Under optimal conditions, the H2 and H2 O2 evolution rates can reach 91 and 116 µmol g-1 h-1 , respectively, with good stability. This work demonstrates the novel application of the few-layer fullerene network in the field of energy conversion.

3.
Arch Biochem Biophys ; 722: 109192, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35367194

RESUMO

TNF, CCN1, and peptidoglycan recognition protein 1 (PGLYRP1) are often found together in the inflammatory tissue. While TNF and CCN1 promote tissue regeneration, PGLYRP1 protects it from bacterial infection. In fibroblasts, CCN1 was reported to support TNF in apoptosis induction while PGLYRP1 was found to compete with TNF for binding to TNFR1. When PGLYRP1 binds to TNFR1 by itself, it silences the receptor, but if HSP70 joins them, it leads to cell death. In cancer cells, however, CCN1 was found to antagonize TNF signaling by increasing the extracellular pool of TNFR1. In this study, we assessed their relationship in the esophageal cancer cells and found a more complex liaison among them. At first, TNF highly upregulated PGLYRP1 expression but downregulated CCN1. Secondly, PGLYRP1 bound TNFR1 and HSP70 both intracellularly and extracellularly, but TNF only promoted their extracellular interaction. Lastly, the knockdown of PGLYRP1 impaired TNF signaling. Taken together, this study shows that CCN1 interrupts TNF signaling by increasing the extracellular TNFR1 species while TNF fights back by upregulating PGLYRP1 to absorb them.


Assuntos
Citocinas/metabolismo , Neoplasias Esofágicas , Receptores Tipo I de Fatores de Necrose Tumoral , Proteínas de Transporte , Amigos , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo
4.
J Am Chem Soc ; 144(1): 99-105, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-34958563

RESUMO

Here we report a general [3 + 2] radical annulation that allows the facile construction of bicyclo[3.2.1]octane motifs in ent-kaurane- and beyerane-type diterpenoids. This radical annulation is difficult to control but was realized by harnessing an unprecedented and counterintuitive effect of TEMPO. Eleven natural products with a wide array of oxidation states are easily prepared, demonstrating the powerful utility of this straightforward synthetic strategy.

5.
J Am Chem Soc ; 142(36): 15240-15245, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32813976

RESUMO

Daphnezomines A and B are structurally unusual Daphniphyllum alkaloids that contain a unique aza-adamantane core skeleton. Herein, a modular approach to these alkaloids is presented that exploits a diverse array of reaction strategies. Commencing from a chiral pool terpene-(S)-carvone, the azabicyclo[3.3.1]nonane backbone, which occurs widely in Daphniphyllum alkaloids, was easily accessed through a Sharpless allylic amination and a palladium-catalyzed oxidative cyclization. A protecting group enabled a stereoselective B-alkyl Suzuki-Miyaura coupling sequence and an Fe-mediated hydrogen atom transfer (HAT)-based radical cyclization were then applied to construct C6 and C8 stereocenters. A final epimer locking strategy enabled the assembly of the highly congested aza-adamantane core, thereby achieving the first total synthesis of (-)-daphnezomines A and B in 14 steps.

6.
Exp Cell Res ; 396(1): 112214, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32768499

RESUMO

Accumulating evidence shows the involvement of long non-coding RNAs (lncRNAs) in tumorigenesis of many types of human cancers. However, the role of LINC00858 in colon cancer has not been fully elucidated. Therefore, we investigated the involvement of LINC00858 in the progression of colon cancer and identified its downstream targets. After examining the expression of LINC00858 in colon cancer tissues and cell lines, we then identified the possible interaction between LINC00858 and WNK lysine deficient protein kinase 2 (WNK2) by fluorescence in situ hybridization, RNA immunoprecipitation, chromatin immunoprecipitation, and RNA pull-down assays. Next, the role of the LINC00858/WNK2 axis was explored by evaluating the apoptosis, autophagy, and senescence of colon cancer cells in vitro after ectopic expression and depletion experiments in HCT116 cells. Moreover, a mouse xenograft model of HCT116 cells was established to verify the function of the LINC00858/WNK2 axis in vivo. There was high expression of LINC00858 and low expression of WNK2 in colon cancer tissues and cell lines. Silencing of LINC00858 promoted apoptosis, senescence, and autophagy in colon cancer cells. Additionally, the enrichment of WNK2 was promoted when LINC00858 bound to DNA methyltransferases. Furthermore, in vivo assays demonstrated that silencing of LINC00858 resulted in inhibited tumor growth by upregulating WNK2. In summary, LINC00858 acts as a tumor-promoting lncRNA in colon cancer by downregulating WNK2. Our results may provide novel targets for the treatment for colon cancer.


Assuntos
Carcinogênese/genética , Neoplasias do Colo/genética , Neoplasias Colorretais/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Serina-Treonina Quinases/genética , RNA Longo não Codificante/genética , Adulto , Idoso , Animais , Apoptose/genética , Autofagia/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Senescência Celular , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Feminino , Células HCT116 , Humanos , Metástase Linfática , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Proteínas Serina-Treonina Quinases/metabolismo , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Carga Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Exp Cell Res ; 393(2): 112025, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32325080

RESUMO

Colon cancer shows characteristics of metastasis, which is associated with angiogenesis. Increasing evidence highlights long non-coding RNAs (lncRNAs) as important participants in angiogenesis of cancers, including colon cancer. Hence, this study investigated the role of HNF1A-AS1 in angiogenesis of colon cancer. RT-qPCR and Western blot analysis were applied to detect HNF1A-AS1 and OTX1 expression in colon cancer tissues and cell lines. Then the interactions among HNF1A-AS1, PBX3, OTX1 and ERK/MAPK pathway were evaluated with RNA pull-down, RIP, ChIP and dual-luciferase reporter gene assays. Next, HCT116 and SW620 cells were treated with si-HNF1A-AS1 and/or oe-OTX1 plasmids to assess the effects of HNF1A-AS1 and OTX1 on angiogenesis, which was further evaluated in nude mice injected with SW620 cells transfected with sh-HNF1A-AS1 or sh-OTX1 lentivirus. HNF1A-AS1 and OTX1 were highly expressed in colon cancer. Silencing of HNF1A-AS1 inhibited angiogenesis of colon cancer in vivo and in vitro. HNF1A-AS1 increased the OTX1 expression by binding to transcription factor PBX3 to promote angiogenesis in colon cancer. Further, HNF1A-AS1 upregulated OTX1 to activate the ERK/MAPK pathway. Altogether, our findings identified HNF1A-AS1 as a tumor-promoting RNA in colon cancer, which could serve as a potential therapeutic target for colon cancer treatment.


Assuntos
Neoplasias do Colo/genética , Fatores de Transcrição Otx/genética , RNA Longo não Codificante/genética , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/genética , Fator 1-alfa Nuclear de Hepatócito/genética , Proteínas de Homeodomínio/genética , Humanos , Camundongos , Neovascularização Patológica/genética , Proteínas Proto-Oncogênicas/genética
8.
Int J Biochem Cell Biol ; 122: 105736, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32135301

RESUMO

Esophageal adenocarcinoma essentially develops from esophageal inflammation caused by chronic GERD. During GERD episodes, the lower esophageal epithelium is repeatedly exposed to stomach acid, which often contains duodenal bile salts that prompt malignant transformation. TRAIL is one of the cytokines produced in response to such insults and targets the transformed cells exclusively. In this study, we simulated GERD episodes in vitro by exposing the cancer cells to acid or acid/bile combination and found that the cancer cells lived through acid attacks by expression of the decoy receptors and c-FLIPR but died of TRAIL-mediated apoptosis when bile salts were present. Further investigation revealed that acid/bile exposure downregulated the decoy receptors and thereby facilitated TRAIL signaling; meantime, it inhibited protein kinase C activity and thus expedited c-FLIPR degradation, allowing apoptosis to take place.


Assuntos
Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Ácidos e Sais Biliares/farmacologia , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/antagonistas & inibidores , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patologia , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Receptores Chamariz do Fator de Necrose Tumoral/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/metabolismo , Linhagem Celular Tumoral , Refluxo Gastroesofágico/induzido quimicamente , Refluxo Gastroesofágico/metabolismo , Refluxo Gastroesofágico/patologia , Humanos , Ácido Clorídrico/farmacologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Transfecção , Receptores Chamariz do Fator de Necrose Tumoral/metabolismo
9.
Angew Chem Int Ed Engl ; 58(32): 10879-10883, 2019 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-31056826

RESUMO

A concise and enantioselective total synthesis of (+)-jungermatrobrunin A (1), which features a unique bicyclo[3.2.1]octene ring skeleton with an unprecedented peroxide bridge, was accomplished in 13 steps by making use of a late-stage visible-light-mediated Schenck ene reaction of (-)-1α,6α-diacetoxyjungermannenone C (2). Along the way, a UV-light-induced bicyclo[3.2.1]octene ring rearrangement afforded (+)-12-hydroxy-1α,6α-diacetoxy-ent-kaura-9(11),16-dien-15-one (4). These divergent photo-induced skeletal rearrangements support a possible biogenetic relationship between (+)-1, (-)-2, and (+)-4.


Assuntos
Compostos Bicíclicos com Pontes/química , Octanos/química , Peróxidos/química , Luz , Estrutura Molecular , Estereoisomerismo
10.
Cytokine ; 116: 61-69, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30685604

RESUMO

GERD is the most common gastrointestinal diagnosis given during office visit. People who suffer from a long history of GERD eventually develop Barrett's esophagus, a premalignant intestinal metaplasia due to NFκB activation. Previous studies focused on the contribution of TNF-triggered canonical NFκB pathway to this event. In this study, we demonstrated in vitro that it was LTA, rather than TNF, initiated canonical NFκB activation at the beginning of acid/bile attacks, but later it switched to CD40-activated non-canonical pathway, which played a bigger part in esophageal metaplasia. CCN1 attenuated this cellular transformation by suppressing CD40 and its associated proteins involved in non-canonical signaling.


Assuntos
Esôfago de Barrett/patologia , Antígenos CD40/metabolismo , Proteína Rica em Cisteína 61/metabolismo , Refluxo Gastroesofágico/patologia , Linfotoxina-alfa/metabolismo , Bile/metabolismo , Linhagem Celular , Regulação da Expressão Gênica , Humanos , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia , Fator de Necrose Tumoral alfa/metabolismo
11.
J Cell Biochem ; 120(2): 2070-2077, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30318638

RESUMO

Many cancer drugs have been developed to control tumor growth by inducing cancer cell apoptosis. However, several intracellular barriers could fail this attempt. One of these barrier is high expression of survivin. Survivin can interfere caspase activation and thereby abort apoptosis. In this study, we found that CCN1 suppressed the survivin expression in tumor cells of esophageal adenocarcinoma (EAC) and thus allowed apoptosis to finish. Furthermore, we demonstrated that this downregulation was dependent on p53 phosphorylation at Ser20, and CCN1 induced EAC cell apoptosis through the activation of p53.

12.
Cell Physiol Biochem ; 48(3): 1012-1018, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30036868

RESUMO

BACKGROUND/AIMS: Fetal macrosomia and its associated complications are the most frequent and serious morbidities for infants associated with gestational diabetes mellitus (GDM). The aim of this study was to evaluate the lncRNAs involvement in GDM, especially for the prediction of risk for fetal overgrowth. METHODS: The peripheral blood obtained from four group including healthy control (NC), healthy volunteers with pregnancy (NC-P), GDM patients with and without macrosomia were screened by lncRNA microarray and validated by quantitative real-time PCR (RT-qPCR) arranged in the training and a two-stage validation sets. The positive and negative prediction ability for candidate lncRNAs were analyzed by risk score analysis. RESULTS: A multiple venny analysis was performed revealed five candidate lncRNA including XLOC_014172, RP11-230G5.2, PCBP1-AS1, LOC149086 and RP11-160H22.5 which was consistence with the following parameter: i, increased in GDM patients with macrosomia (GDM-M) comparing with patients without macrosomia; ii, increased in GDM-M comparing with NC-P group; iii, increased in GDM-M comparing with NC. Further validation found XLOC_014172 and RP11-230G5.2 was final consistence with these parameter in 150 samples each group. Further receiver operating characteristic curve (ROC) analysis, with the combined two stably expressed lncRNAs indicated a high diagnostic ability an area under ROC curve value (AUC) of 0.955 and 0.962 in training set and validation set respectively. CONCLUSIONS: Circulating XLOC_014172 and RP11-230G5.2 may act as novel biomarkers in GDM patients as fingerprint for the risk of macrosomia outcome.


Assuntos
Diabetes Gestacional/diagnóstico , Macrossomia Fetal/diagnóstico , RNA Longo não Codificante/sangue , Adulto , Área Sob a Curva , Biomarcadores/sangue , Estudos de Casos e Controles , Diabetes Gestacional/sangue , Feminino , Macrossomia Fetal/etiologia , Teste de Tolerância a Glucose , Hemoglobinas Glicadas/análise , Humanos , Gravidez , Complicações na Gravidez , Curva ROC , Fatores de Risco
13.
J Nat Prod ; 81(2): 298-306, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29394050

RESUMO

Acute myeloid leukemia (AML) is a hematologic malignancy that is characterized by clonal proliferation of myeloid blasts. Despite the progress that has been made in the treatment of various malignant hematopoietic diseases, the effective treatment of AML remains very challenging. Differentiation therapy has emerged as a promising approach for leukemia treatment, and new and effective chemical agents to trigger the differentiation of AML cells, especially drug-resistant cells, are urgently required. Herein, the natural product jungermannenone C, a tetracyclic diterpenoid isolated from liverworts, is reported to induce cell differentiation in AML cells. Interestingly, the unnatural enantiomer of jungermannenone C (1) was found to be more potent than jungermannenone C in inducing cell differentiation. Furthermore, compound 1 targets peroxiredoxins I and II by selectively binding to the conserved cysteine residues and leads to cellular reactive oxygen species accumulation. Accordingly, ent-jungermannenone C (1) shows potential for further investigation as an effective differentiation therapy against AML.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Diterpenos/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Hepatófitas/química , Humanos , Leucemia Mieloide Aguda/metabolismo , Peroxirredoxinas/farmacologia
14.
Exp Cell Res ; 361(1): 163-169, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29055676

RESUMO

TRAIL is one of the best anti-cancer molecules in our body. It kills a variety of cancer cells that are resistant to conventional chemotherapy, without causing much negative impact on normal cells, because its death receptors are almost exclusively found on cancer cells. However, some cancer cells are not sensitive to TRAIL treatment, even though they express its death receptors. A second molecule is needed to help TRAIL to complete its mission. Finding such molecules now becomes a top priority in cancer research. Our study shows that CCN1 is such a molecule. CCN1 was highly expressed in the esophageal epithelium of the patients suffering from gastroesophageal reflux disease, but faded away as the situation worsened towards adenocarcinoma. Treating the tumor cells with CCN1 resulted in apoptosis, while the same treatment to the normal cells only nourished cell growth. It was TRAIL that mediated this process. Apparently, CCN1 altered the expression profile of TRAIL and its receptors in tumor cells, namely, activating TRAIL and its death receptors and shutting down its decoy receptors. CCN1 and TRAIL worked as a team to put the cancer cells to death, as elimination of either one failed apoptosis.


Assuntos
Adenocarcinoma/patologia , Apoptose , Proteína Rica em Cisteína 61/metabolismo , Neoplasias Esofágicas/patologia , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Proliferação de Células , Proteína Rica em Cisteína 61/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/metabolismo , Humanos , Ligante Indutor de Apoptose Relacionado a TNF/genética , Células Tumorais Cultivadas
15.
Sci Rep ; 7(1): 9727, 2017 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-28852077

RESUMO

This study reports a mechanical stress-based technique that involves scratching or imprinting to write textured graphite conducting wires/patterns in an insulating amorphous carbon matrix for potential use as interconnects in future carbonaceous circuits. With low-energy post-annealing below the temperature that is required for the thermal graphitization of amorphous carbon, the amorphous carbon phase only in the mechanically stressed regions transforms into a well aligned crystalline graphite structure with a low electrical resistivity of 420 µΩ-cm, while the surrounding amorphous carbon matrix remains insulating. Micro-Raman spectra with obvious graphitic peaks and high-resolution transmission electron microscopic observations of clear graphitic lattice verified the localized phase transformation of amorphous carbon into textured graphite exactly in the stressed regions. The stress-induced reconstruction of carbon bonds to generate oriented graphitic nuclei is believed to assist in the pseudo-self-formation of textured graphite during low-temperature post annealing.

16.
Chem Asian J ; 12(13): 1557-1567, 2017 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-28440575

RESUMO

We report herein our synthetic efforts towards the divergent syntheses of (-)-huperzine Q (1), (+)-lycopladine B (2), (+)-lycopladine C (3), and (-)-lycopladine D (4). The 10-step total synthesis of (-)-huperzine Q (1) and the first total syntheses of (+)-lycopladines B (2) and C (3) were accomplished through a series of cascade reactions. Our approach involved a Michael addition/aldol/intramolecular C-alkylation sequence to forge the 6/9 spirocycle ring, and this was followed by an ethylene-accelerated carbonyl-olefin metathesis to construct the common 6/5/9 ring system. Finally, late-stage enamine bromofunctionalization enabled us to access (-)-huperzine Q (1), (+)-lycopladine B (2), and (+)-lycopladine C (3), and a tandem C4-epimerization/retro-Claisen condensation furnished (-)-4-epi-lycopladine D (63).


Assuntos
Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Sesquiterpenos/síntese química , Compostos de Espiro/síntese química , Compostos Heterocíclicos de 4 ou mais Anéis/química , Estrutura Molecular , Sesquiterpenos/química , Compostos de Espiro/química , Estereoisomerismo
17.
Nan Fang Yi Ke Da Xue Xue Bao ; 35(7): 1059-62, 1072, 2015 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-26198962

RESUMO

OBJECTIVE: To explore the clinical value of screening the serum markers during the second trimester of pregnancy in preventing congenital birth defect and predicting the pregnancy outcome. METHODS: Between November, 2011 and October, 2013, a total of 25 520 pregnant women (15-20+6 gestational weeks) underwent a screening test of triple serum markers including free beta-human chorionic gonadotrophin (free ßhCG), alpha-fetoprotein (AFP), and unconjugated estriol (µE3) during the second semester of pregnancy. The women identified by the screening test as having high risks were referred to invasive prenatal diagnosis by amniocentesis, or to color Doppler ultrasound examination for suspected patent neural tube defect (NTD), and their pregnancy outcomes were followed up. RESULTS: High-risk pregnancies were identified by the screening test in 4.91% (1254/25520) of the total cohort. Of the 818 patients receiving invasive prenatal diagnosis, the abnormal rate was 5.75% (47/818). The high-risk pregnancies identified by the screening test was associated with a significantly higher rate of abnormal outcomes compared with the low-risk pregnancies (1.91% vs 0.1%, P<0.01). Of the 210 high-risk cases of NTD, a definite diagnosis was established in 34 cases. We also found that pregnancies at an advanced age (>35 years) was associated with increased risks for trisomy 21 compared with those at younger ages (15% vs 1.65%P<0.01). The detection rate of abnormal karyotypes in pregnancies with an abnormal MoM value of a single marker was 3.17% (6/189). CONCLUSION: Screening tests of serum markers during the second trimester of pregnancy can be helpful to identify fetal chromosomal and anatomical anomalies, predict unfavorable pregnancy outcomes, and prevent birth defects in pregnancies at an advanced age. The MoM value of a single marker in the second trimester can be indicative of potential chromosomal abnormalities.


Assuntos
Biomarcadores/sangue , Resultado da Gravidez , Segundo Trimestre da Gravidez/sangue , Diagnóstico Pré-Natal , Gonadotropina Coriônica Humana Subunidade beta/sangue , Aberrações Cromossômicas , Síndrome de Down/diagnóstico , Estriol/sangue , Feminino , Humanos , Defeitos do Tubo Neural/diagnóstico , Gravidez , alfa-Fetoproteínas/análise
18.
Angew Chem Int Ed Engl ; 54(3): 1011-5, 2015 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-25358669

RESUMO

Utilizing a late-stage enamine bromofunctionalization strategy, the twelve-step total synthesis of (-)-huperzine Q was accomplished. Furthermore, the first total syntheses of (+)-lycopladines B and C are described. An unprecedented X-ray crystal structure of an unusual epoxyamine intermediate is also reported, and the synthetic application of this intermediate in natural product synthesis is demonstrated.


Assuntos
Alcaloides/síntese química , Hidrocarbonetos Aromáticos com Pontes/síntese química , Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Compostos de Espiro/síntese química , Alcaloides/química , Alquilação , Hidrocarbonetos Aromáticos com Pontes/química , Cristalografia por Raios X , Ciclização , Ácidos Cicloexanocarboxílicos/química , Compostos Heterocíclicos de 4 ou mais Anéis/química , Cetonas/química , Conformação Molecular , Compostos de Espiro/química , Estereoisomerismo
19.
Nat Commun ; 5: 4614, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25082077

RESUMO

Natural products continue to provide a rich source of inspiration for both chemists and biologists. The efficient synthesis of bioactive natural products or natural product-like molecules has offered tremendous opportunities for complex biological processes exploration and drug discovery. However, because natural products usually contain numerous stereogenic centres and polycyclic ring systems, significant synthetic challenges remain. Here we employ the build/couple/pair strategy that is frequently used in diversity-oriented synthesis to obtain skeletally diverse compounds with complexities comparable to natural products. Inspired by the functional group pairing patterns hidden in Lycopodium alkaloids, we efficiently and in parallel construct four natural products, (+)-Serratezomine A, (-)-Serratinine, (+)-8α-Hydroxyfawcettimine and (-)-Lycoposerramine-U, as well as six different unnatural scaffolds, following the advanced build/couple/pair algorithm. This newly developed strategy is expected to be applied to the efficient synthesis of other complex natural products possessing functional group pairing patterns as well as skeletally diverse natural product-like molecules.


Assuntos
Alcaloides/química , Produtos Biológicos/química , Materiais Biomiméticos/síntese química , Compostos Heterocíclicos com 3 Anéis/síntese química , Lycopodium/química , Alcaloides/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Técnicas de Química Analítica , Ciclização , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/isolamento & purificação , Indolizinas/química , Indolizinas/isolamento & purificação , Estrutura Molecular
20.
Artigo em Inglês | MEDLINE | ID: mdl-24211812

RESUMO

The interaction between triphenyltin (TPT) and human serum albumin (HSA) in physiological buffer (pH=7.4) was investigated by the fluorescence quenching technique. The results of fluorescence titration revealed that TPT could strongly quench the intrinsic fluorescence of HSA through a static quenching procedure. The apparent binding constants K and number of binding sites n of TPT with HSA were 2.51×10(3) and 0.96 at 298 K which were obtained by the fluorescence quenching method. The thermodynamic parameters enthalpy change (ΔH), entropy change (ΔS) were positive, which indicated that the interaction of TPT with HSA was driven mainly by hydrophobic forces. The process of binding was a spontaneous process in which Gibbs free energy change was negative. The distance r between donor (HSA) and acceptor (TPT) was calculated to be 3.13 nm based on Forster's non-radiative energy transfer theory. The results of synchronous fluorescence, three-dimensional fluorescence and circular dichroism (CD) spectra showed that the triphenyltin induced conformational changes of HSA.


Assuntos
Disruptores Endócrinos/metabolismo , Compostos Orgânicos de Estanho/metabolismo , Albumina Sérica/metabolismo , Disruptores Endócrinos/toxicidade , Humanos , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos de Estanho/toxicidade , Ligação Proteica , Conformação Proteica/efeitos dos fármacos , Albumina Sérica/química , Espectrometria de Fluorescência , Termodinâmica
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