1,720,974 research outputs found
Abstract 1266: Metformin represses esophageal carcinogenesis in NMBzA-treated rat model through inhibiting AMPK/mTOR and Stat3 signaling pathways
No full textAbstract
Esophageal cancer is one of the most aggressive tumor types because of its invasiveness and metastatic potential. Metformin is one of the most used diabetic drugs for the management of type 2 diabetes mellitus in the world. The role of metformin in prevention of the development and progression of a variety of human tumors has been studied. However, the detailed mechanisms have not yet been fully understood. In the present study, we investigated the effects of metformin on the suppression of esophageal carcinogenesis in a rat model, in which F344 rats were treated with N-nitroso-N-methylbenzylamine (NMBzA 0.30 mg/kg s.c.) three times per week for 35 weeks to induce esophageal tumors. To monitor the effects of metformin in this model, one group of rats were administered with metformin (3 g/L) in the drinking water at the first NMBzA injection. Our results showed that although there was no significant difference in body weight in rats of different groups, rats treated with NMBzA and metformin together significantly reduced the tumor formation and tumor volume when compared with rats treated with NMBzA alone. Statistic analyses demonstrated that the tumor numbers was reduced in NMBzA-treated rats received metformin to an average of 1.85 ± 1.09 tumors per rat when compared with 10.85 ± 3.86 (P < 0.001) in rats without metformin, while the tumor volume was decreased from 70.79 ± 41.65 mm3 per rat without metformin administration to 8.64 ± 13.45 mm3 (P < 0.001) with metformin administration. In addition, 7 out of 24 rats in the NMBzA-treated group died before week 35 but no rats died in the other groups. Furthermore, immunoblotting analysis indicated that p-mTORSer2448, p-Stat3Tyr705, and Cyclin D1 protein levels significantly decreased, while p-AMPKThr172 significantly increased in tumors obtained from rats treated with NMBzA and metformin when compared with tumors obtained from rats treated with NMBzA alone. Thus, our results indicated that metformin suppressed NMBzA-induced esophageal carcinogenesis via inhibition of the AMPK/mTOR and Stat3 signaling pathways. Together, our study suggested that metformin might have a potential use for treatment and prevention of esophageal cancer.
Citation Format: Hongjun Fan, Zhigeng Zou, Xiying Yu, Liping Guo, Wei Jiang, Shih-Hsin Lu. Metformin represses esophageal carcinogenesis in NMBzA-treated rat model through inhibiting AMPK/mTOR and Stat3 signaling pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1266. doi:10.1158/1538-7445.AM2017-1266</jats:p
Abstract 1901: DNMT1 is involved in esophageal squamous cell carcinoma (ESCC) and self-renewal ability of ESCC-cancer stem cells
No full textAbstract
DNA methylation mediated by DNA methyltransferase 1 (DNMT1) plays an important role in carcinogenesis and self-renewal ability of cancer stem cells (CSCs). However, the function of DNMT1 in esophageal squamous cell carcinoma (ESCC) carcinogenesis, especially self-renewal ability of ESCC-CSCs remains unclear. In this study, we found a high expression of DNMT1 in both side population (SP) cells and sphere formation cells that represented as substitutes for CSCs in KYSE150 and EC109 ESCC cell lines. In addition, the expression of DNMT1 was decreased during the differentiation from SP to None-SP (NSP) in these ESCC cells. These results suggested that DNMT1 might have a role in regulating self-renewal and/or differentiation of ESCC-CSCs. To further investigate DNMT1 in ESCC carcinogenesis and self-renewal ability of ESCC-CSCs, we silenced the expression of DNMT1 in KYSE150 and EC109 ESCC cells using lentivirus-mediated RNA interference (RNAi). Our results showed that ablation of DNMT1 expression in KYSE150 and EC109 ESCC cells resulted in decreased their CSCs by SP analysis and sphere formation assay. Meanwhile, ablation of DNMT1 expression inhibited malignant phenotypes in KYSE150 and EC109 cells, including cell proliferation, colony formation, migration and drug resistance abilities. Treatment of 5-aza-2'-deoxycytidine (5-aza-dC), a DNMT inhibitor that led to the degradation of DNMT1 protein by proteasome, revealed that numbers of CSCs and the malignant phenotypes of KYSE150 and EC109 ESCC cells were refrained significantly, including a dramatic inhibition of self-renewal ability of these ESCC-CSCs. Thus, our results indicated that DNMT1 was involved in ESCC carcinogenesis, especially in the maintenance of ESCC-CSCs, suggesting that DNMT1 could be a potential target for ESCC, especially ESCC-CSCs, therapy.
Citation Format: Ying Teng, Xiying Yu, Hui Yuan, Liping Guo, Wei Jiang, Shih-Hsin Lu. DNMT1 is involved in esophageal squamous cell carcinoma (ESCC) and self-renewal ability of ESCC-cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1901. doi:10.1158/1538-7445.AM2017-1901</jats:p
Abstract 1262: Aspirin inhibits the carcinogenesis of esophageal squamous cell carcinoma and enhances its responses to cisplatin
No full textAbstract
Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies. Over 70% of ESCC cases occur in China. Unfortunately, the treatment of ESCC has hardly been improved all these years. Several studies suggested that aspirin (ASA) might decrease the risk of ESCC and prolonged the survival of patients with ESCC. However, it is unclear if ASA could prevent ESCC and/or enhance ESCC treatment by chemotherapy. In this study, a N-nitroso-N-methylbenzylamine (NMBzA) - induced ESCC model was employed to prove that aspirin could prevent the growth of esophageal tumor. F344 rats were treated with NMBzA by subcutaneous injection with or without ASA in drinking water (2mg/ml). After 35 week ASA-NMBzA or NMBzA alone treatment, rats were killed and esophageal tumor development were examined. The results showed that F344 rats treated with NMBzA and receiving a daily intake of ASA developed much less tumors than F344 rats treated with NMBA alone both in amount and in size (Tumor count: 2.40 ± 1.57 vs 10.85 ± 3.86 , P &lt; 0.001; Tumor volume: 11.10 ± 13.38 mm3 vs 70.79 ± 41.65 mm3, P &lt; 0.001). Immunohistochemical analysis indicated that a higher rate of apoptosis was observed in the basal layer of esophageal epithelium in ASA-NMBzA treated rats than in NMBzA alone treated rats. These results indicated that ASA prevented development of esophageal tumors in rats induced by NMBzA. Moreover, using in vitro human ESCC cell culture and in vivo xenograft models, we showed that ASA has strong beneficial effects on inhibition of ESCC cell proliferation and colony formation, reduction of ESCC cancer stem cells and enhance of ESCC cell cytotoxicity induced by cisplatin treatment. Biochemical analysis revealed that these effects of ASA on human ESCC cells in vitro and in vivo were due to inhibiting the repairing of DNA damage, decreasing the efflux activity and ALDH1 activity of the tumor cells, and blockades of PI3K/Akt pathway. Thus, our results demonstrated a positive role of aspirin in the prevention and treatment of ESCC.
Note: This abstract was not presented at the meeting.
Citation Format: Zhigeng Zou, Hongjun Fan, Xiying Yu, Shuming Zhang, Liping Guo, Wei Jiang, Shih-Hsin Lu. Aspirin inhibits the carcinogenesis of esophageal squamous cell carcinoma and enhances its responses to cisplatin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1262. doi:10.1158/1538-7445.AM2017-1262</jats:p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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