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1.
Food Chem ; 305: 125447, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499289

RESUMO

A novel α-amylase gene (RmAmyA) from Rhizomucor miehei was cloned and expressed in Pichia pastoris. RmAmyA showed 70% amino acid identity with the α-amylase from Rhizomucor pusillus. A high α-amylase activity of 29,794.2 U/mL was found through high cell density fermentation. The molecular mass of RmAmyA was determined to be 49.9 kDa via SDS-PAGE. RmAmyA was optimally active at 75 °C and pH 6.0, and it did not require Ca2+ to improve its activity. It exhibited broad substrate specificity towards amylose, amylopectin, soluble starch, pullulan, and cyclodextrins. High level of maltose (54%, w/w) was produced after liquefied starch was hydrolysed with RmAmyA for 16 h. Moreover, the addition of RmAmyA into Chinese steamed bread resulted in 7.7% increment in the specific volume, and 17.2% and 11.5% reduction in the chewiness and hardness, respectively. These results indicate that RmAmyA might be a potential candidate for applications in the food industry.

2.
Cancer Lett ; 451: 79-91, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30872078

RESUMO

Vemurafenib is a B-Raf V600E inhibitor that exerts significant inhibitory effects in melanoma but not in colon cancer, and the mechanism of vemurafenib resistance remains unclear. In this study, bioinformatics analysis of gene profiles in cancer cells treated with vemurafenib or its analog revealed that cell cycle progression is significantly affected by vemurafenib. We found that CDK1 is stably activated in the vemurafenib-resistant (VR) colon cancer sublines that we established, indicating that CDK1 activation is responsible for vemurafenib resistance. As the KCTD12-CDK1 interaction is necessary for CDK1 activation, we screened an FDA-approved drug library consisting of 616 compounds and identified that adefovir dipivoxil (AD), a nucleoside analog for treatment of HBV infections, disrupts the CDK1-KCTD12 interaction and induces G2 phase arrest in the cell cycle. Functional assays demonstrated that AD significantly inhibited colon cancer cell proliferation and tumorigenesis both in vitro and in vivo with no observed side effects. Furthermore, AD sensitized vemurafenib-resistant colon cancer cells and tumor xenografts to vemurafenib. This study reveals that CDK1 activation induces vemurafenib resistance and that AD is a promising therapeutic strategy for colon cancer both as a single agent and in combination with vemurafenib.

3.
J Proteome Res ; 17(1): 265-275, 2018 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-29072916

RESUMO

Metastasis is one of the major causes of treatment failure in the patients with colon cancer. The aim of our study is to find key proteins and pathways that drive invasion and metastasis in colon cancer. Eight rounds of selection of cancer cells invading through matrigel-coated chamber were performed to obtain highly invasive colon cancer sublines HCT116-I8 and RKO-I8. Stable Isotope Labeling by Amino Acids in Cell Culture technology was used to identify the differently expressed proteins, and the proteomics data were analyzed by ingenuity pathway analysis. PAK1-PBD immunoprecipitation combined with Western blot were carried out to determine Cdc42 activity, and qRT-PCR and Western blot were used to determine gene expression. The functional role of Cdc42BPA and Cdc42 pathway in colon cancer invasion was studied by loss-of-function experiments including pharmacological blockade, siRNA knockdown, chamber invasion, and WST-1 assays. Human colon cancer tissue microarray was analyzed by immunohistochemistry for overexpression of Cdc42BPA and its correlation with clinicopathological parameters and patient survival outcomes. HCT116-I8 and RKO-I8 cells showed significantly stronger invasive potential as well as decreased E-cadherin and increased vimentin expressions compared with parental cells. The differently expressed proteins in I8 cells compared with parental cells were identified. Bioinformatics analysis of proteomics data suggested that Cdc42BPA protein and Cdc42 signaling pathway are important for colon cancer invasion, which was confirmed by experimental data showing upregulation of Cdc42BPA and higher expression of active GTP-bound form of Cdc42 in HCT116-I8 and RKO-I8 cells. Functionally, pharmacological and genetic blockade of Cdc42BPA and Cdc42 signaling markedly suppressed colon cancer cell invasion and reversed epithelial mesenchymal transition process. Furthermore, compared with adjacent normal tissues, Cdc42BPA expression was significantly higher in colon cancer tissues and further upregulated in metastatic tumors in lymph nodes. More importantly, Cdc42BPA expression was correlated with metastasis and poor survival of the patients with colon cancer. This study provides the first evidence that Cdc42BPA and Cdc42 signaling are important for colon cancer invasion, and Cdc42BPA has potential implications for colon cancer prognosis and treatment.


Assuntos
Neoplasias do Colo/patologia , Miotonina Proteína Quinase/metabolismo , Transdução de Sinais , Proteína cdc42 de Ligação ao GTP/metabolismo , Biomarcadores , Linhagem Celular Tumoral , Humanos , Invasividade Neoplásica , Prognóstico , Proteômica
4.
Oncotarget ; 8(24): 38755-38766, 2017 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-28418888

RESUMO

Metastasis is the most lethal hallmark of esophageal squamous cell carcinoma (ESCC). The aim of the study is to identify key signaling pathways that control metastasis in ESCC. Highly invasive ESCC sublines (designated I3 cells) were established through three rounds of selection of cancer cells invading through matrigel-coated chambers. Gene expression profile of one of the I3 sublines was compared with that of its parental cell line using cDNA microarray analysis. Gene ontology and pathway analyses of the differentially expressed genes (both upregulated and downregulated) indicated that genes associated with cellular movement and the AKT pathway were associated with increased cancer cell invasiveness. Western blot analysis confirmed increased phosphorylated AKT (p-AKT), N-cadherin and decreased E-cadherin expression in the I3 cells. Immunohistochemistry was used to evaluate the clinical significance of p-AKT expression in ESCC, and the results showed higher p-AKT nuclear expression in lymph node metastases when compared with primary carcinoma. Inactivation of the PI3K/AKT pathway with specific inhibitors, or with PTEN overexpression, resulted in reversed cadherin switching and inhibited cancer cell motility. Inhibition of the pathway by treatment with wortmannin markedly suppressed experimental metastasis in nude mice. Our data demonstrated the importance of the PI3K/AKT signaling pathway in ESCC metastasis and support PI3K/AKT as a valid therapeutic target in treatment of metastatic ESCC.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/secundário , Neoplasias Esofágicas/patologia , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Apoptose , Carcinoma de Células Escamosas/metabolismo , Movimento Celular , Proliferação de Células , Neoplasias Esofágicas/metabolismo , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Metástase Linfática , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica , Fosforilação , Prognóstico , Transdução de Sinais , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Biochem Pharmacol ; 129: 43-53, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28104435

RESUMO

6-O-Angeloylenolin (6-OA), a sesquiterpene lactone isolated from Centipeda minima (L.) A. Br. (Compositae), has been used to treat respiratory diseases for centuries. However, whether and how 6-OA exerts anticancer effects against lung cancer remains to be elucidated. In this study, we showed that 6-OA markedly suppressed the cell viability and colony formation of lung cancer cells H1299 and A549, with no significant toxic effect on non-cancer cells HBE. Annexin V/7-AAD assay revealed that 6-OA induced cell apoptosis in dose- and time-dependent manners, which was further confirmed by the increased expression of cleaved caspase-3. To uncover the molecular mechanism how 6-OA exerts its anticancer effects, SILAC quantitative proteomics was performed to identify 6-OA-regulated proteins in lung cancer cells. Ingenuity Pathway Analysis revealed that these 6-OA-regulated proteins were mainly involved in Nrf2-mediated oxidative stress response, which was confirmed by the nuclear translocation of Nrf2 upon 6-OA treatment. Moreover, we found that 6-OA stimulated the accumulation of reactive oxygen species (ROS), whereas inhibition of ROS generation with N-acetyl l-cysteine could block the 6-OA-induced anticancer effects. Furthermore, blockade of cellular anti-oxidative system by Nrf2 knockdown significantly augmented the 6-OA-induced apoptosis. Taken together, we demonstrated that 6-OA exerts its anticancer effects by generating ROS, and inhibition of Nrf2 anti-oxidative system potentiated these effects. These results suggest that 6-OA may be used to treat lung cancer, with better outcome by combining with Nrf2 inhibitor to block Nrf2 pathway.


Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos/uso terapêutico , Lactonas/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Fator 2 Relacionado a NF-E2/antagonistas & inibidores , Sesquiterpenos/uso terapêutico , Adenocarcinoma/patologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Lactonas/farmacologia , Neoplasias Pulmonares/patologia , Espécies Reativas de Oxigênio/metabolismo , Sesquiterpenos/farmacologia
6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(7): 1267-70, 2007 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-17944391

RESUMO

The energy band structures, optical absorption spectra and reflectivity of the semiconducting single-wall carbon nano-tubes (7,0) and (8,0), with symmetrical Stone-Wales defects on (7,0) and symmetrical Stone-Wales defects on (8,0) and (7, 0)-(8,0) SWCNT heterojunction were studied using the density functional theory, and the results were compared. It is shown that the energy band structures have changed obviously, and according to different kind of defects the Fermi energy levels were shifted in different direction. The absorption and reflectivity weakened obviously and red shift of absorption peak and reflectivity peak have occurred in the lower energy region, when the carbon nanotube contained topological defects compared to perfect single-wall carbon nanotubes. There was a distinct peak in the five carbon nanotubes at the photon energy of about E = 13 eV, and the peak shifted to high energy region when the nanotube contained defects. The results were analyzed and discussed theoretically. The authors can take advantage of the photoelectricity property created by topological defect to design photoelectricity device.

7.
Shanghai Kou Qiang Yi Xue ; 13(1): 34-7, 2004 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-15007478

RESUMO

PURPOSE: To screen effective chemopreventive Chinese herb drugs on experimental oral carcinogenesis. METHODS: 410 golden hamsters were randomly divided into positive control group,negative control group and 7 experimental groups(Radix et Rhizoma Thalictri, Radix Sophorae Tonkinesis, Pseudobulbus Cremastrae appendiculate, Rhizoma Acori Tatarinowii, Radix Angelicae seu Heraclei, Rhizoma Curcumae, Fructus Trichosanthis). 7,12-Dimethylbenz(a)anthracene(DMBA) was used to induce oral carcinogenesis in hamster cheek pouch, 7 liquid Chinese herb drugs were respectively injected into the stomach of the hamsters before and during oral carcinogenesis. Specimens were observed by histopathologic method, and the results were analysized statistically. RESULTS: Compared with positive control group, the prevalence of displasia was significantly reduced in group Radix Sophorae Tonkinesis and Radix Angelicae Dahuricae, but significant decrease could not be found in other experiment groups. CONCLUSION: Radix Sophorae Tonkinesis and Radix Angelicae Dahuricae could effectively intercept DMBA-induced oral carcinogenesis in hamster.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Neoplasias Bucais/tratamento farmacológico , Animais , Cricetinae , Ensaios de Seleção de Medicamentos Antitumorais , Mesocricetus , Neoplasias Bucais/patologia
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