RAS protein activator-like 1 (RASAL1) is a member of the RAS GTPase-activating protein family, and previous studies indicate that RASAL1 is involved in the progression of hypoxia resistance in breast cancer cells. In the present study, increased levels of hypoxia inducible factor-1α (HIF-1α) were observed to be accompanied with increased expression of RASAL1 in the breast cancer cell lines MCF-7 and MDA-MB-231 cells under hypoxia. Based on this, it was postulated that RASAL1 may serve a functional role in the development of hypoxia resistant in breast cancer cells. In the present study it was demonstrated that: i) Exogenous expression of RASAL1 in MCF-7 and MDA-MB-231 sensitized its reaction to the treatment of hypoxia, which is associated with its ability to directly reduce HIF-1α expression, inhibit migration activity and decrease the accumulation of reactive oxygen species (ROS); ii) knockdown of RASAL1 reversed its reaction to treatment with hypoxia; iii) RASAL1 directly regulated the expression of HIF-1α through the ROS-mediated, extracellular signal-regulated kinase and Akt pathway. These findings provide direct evidence that the RASAL1/HIF-1α axis may serve an essential role in the hypoxia resistance of breast cancer cells, suggesting that this signaling cohort may serve as a novel therapeutic target for the treatment of breast cancer.
Blogs are a new type of media that have recently become popular users on the World Wide Web and have influence throughout society. Developing an explanatory theoretical model of website usability is pivotal for understanding usable website design. Such a model would explain and help predict the effects of website usability on online purchases, but few studies have been devoted to such model development. As an exploratory effort, we adopted and extended Kaplan's landscape preference model by including factors of legibility, coherence, variety, and mystery, and examined their effect on cognitive and affective appraisals and their impact on behavioral intention, including word-of-mouth, continued intention, and complaint. A field survey with 280 online customers of websites was conducted to validate the research model. Our findings demonstrated that the proposed model explained a large amount of the variance of behavioral intention. Key implications for theory and practice are discussed. This study contributes to a theoretical understanding of the factors as landscape preference that affect the usage intention of blogs. Practically this study results provide blog service providers useful strategic insights and service guideline to enhance user's intention of blogs.
Cuscutae Semen (CS; Chinese common name “Tusizi”) is one of the most common traditional herbal medicines used to treat liver and kidney diseases in China. Although it is most commonly used as a processed product, little progress has been made on the quality control of CS and salt-processed Cuscutae Semen (PCS). The purpose of this study was to establish a comprehensive strategy integrating chromatographic analysis and chemometric methods for quality evaluation and discrimination of CS and PCS. An accurate and reliable HPLC method was established for the simultaneous quantification of 12 analyte compounds in CS and PCS. The results showed that this method exhibited desirable sensitivity, precision, stability, and repeatability. Multivariate chemometric methods were applied to analyze the obtained HPLC fingerprints, including hierarchical cluster analysis (HCA), principle component analysis (PCA), and partial least squares discriminant analysis (PLS-DA). The results indicated that CS and PCS samples showed a clear classification of the two groups, and three chemical markers with great contributions to the differentiation were screened out. Collectively, the chemometrics combined with the quantitative analysis based on HPLC fingerprint results indicated that salt processing may change the contents and types of components in Cuscutae Semen.
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