Galectin-1 Promotes Metastasis in Gastric Cancer Through a Sphingosine-1-Phosphate Receptor 1-Dependent Mechanism

Background/Aims: Increased expression of galectin-1 (Gal-1) in gastric cancer (GC) promotes metastasis and correlates with poor prognosis. The mechanisms by which Gal-1 promotes GC metastasis remain unknown. Methods: Gal-1and Sphingosine-1-phosphate receptor 1 (S1PR1) were determined by immunohistochemistry(IHC) and quantitative real time polymerase chain reaction (qRT-PCR) in GC specimens. Stably transfected Gal-1 or S1PR1 into SGC7901 and MGC-803 cells, western blot and invasion assays in vitro and nude mice tumorigenicity in vivo were also employed. Results: Overexpression of Gal-1 enhanced expression of S1PR1 in SGC-7901 cells, and increased cell invasion, while knockdown Gal-1 in MGC-803 cells reduced S1PR1 expression and diminished invasion. Simultaneous knockdown of Gal-1 and overexpression of S1PR1 in MGC803 cells rescued invasive ability of MGC803 cells. S1PR1 was associated with expression of epithelial-to-mesenchymal transition (EMT) markers in vitro and in clinical samples. EMT induced in MGC-803 cells by TGF-β1 was accompanied by S1PR1 activation, while knockdown of S1PR1 reduced response to TGF-β1, suggest that Gal-1 promotes GC invasion by activating EMT through a S1PR1-dependent mechanism. Overexpression of S1PR1 promoted subcutaneous xenograft growth and pulmonary metastases, and enhanced expression of EMT markers. Conclusion: Galectin-1 promotes metastasis in gastric cancer through a S1PR1- dependent mechanism, our results indicate that targeting S1PR1 may be a novel strategy to treat GC metastasis

A recyclable solid catalyst of KF/Ca-Mg-Al-O using for biodiesel production from jatropha seed oil: preparation, characterization, and methanolysis process optimization

A recyclable heterogeneous KF/Ca-Mg-Al-O catalyst was prepared by co-precipitation and calcination processes. The characteristics of the catalyst were investigated using FTIR, XRD, TG-DTG and SEM. Response surface methodology was utilized to obtain the best most extreme biodiesel production yield. The ideal biodiesel production conditions were: the amount of catalyst was 3 wt%; the reaction temperature was 65 °C; the alcohol oil molar ratio 9.8:1, the reaction time was 3.5 h. Under these amended conditions, the average biodiesel yield was 95.19%, which is well in close concurrence with the worth anticipated by the model. The repeatability of catalysts was studied. After using the catalyst seven times, the catalytic efficiency was only reduced by 2.7%. These results indicate that the catalyst has good catalytic efficiency and is recyclable

Hydrogenation of carbon dioxide to light olefins over non-supported iron catalyst

National Basic Research Program of China (973 Program) [2013CB933100]; National Natural Science Foundation of China [21173174, 20923004, 21033006, 21161130522]; Specialized Research Fund for the Doctoral Program of Higher Education [20090121110007]; Program for Innovative Research Team in University [IRT1036]The hydrogenation of CO2 to light olefins was investigated over non-supported Fe catalysts. It was found that the addition of alkali metal ions to the Fe catalyst led to significant increases in both the CO2 conversion and the selectivity for olefins. Over K- or Rb-modified catalysts, about 40% CO2 conversion and more than 50% olefin selectivity were obtained. The yield of C-2-C-4 olefins exceeded 10% over these modified catalysts. Catalyst characterization suggested that the formation of iron carbide species was accelerated by the modification of the Fe catalyst with alkali metal ions, and this enhancement may be one of the key reasons for the enhanced catalytic performance. For the K-modified Fe catalysts, K content has a major influence on the catalyst behavior. An increase in the K content from 1 to 5 wt% increased both CO2 conversion and olefin selectivity. However, too high a K content led to a decrease in the activity, probably because of decreases in the surface area and CO2 chemisorption capacity of the catalyst. The presence of an appropriate amount of B in the K-modified Fe catalyst was found to be beneficial to the olefin selectivity, without significantly decreasing the conversion of CO2. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

Knockdown of ARK5 Expression Suppresses Invasion and Metastasis of Gastric Cancer

Background/Aims: Gastric cancer (GC) is a common and lethal malignancy, and AMP-activated protein kinase-related kinase 5 (ARK5) has been discovered to promote cancer metastasis in certain types of cancer. In this study, we explored the role of ARK5 in GC invasion and metastasis. Methods: ARK5 and epithelial-mesenchymal transition (EMT)-related markers were determined by immunohistochemistry and western blot in GC specimens. Other methods including stably transfected against ARK5 into SGC7901 and AGS cells, western blot, migration and invasion assays in vitro and nude mice tumorigenicity in vivo were also employed. Results: The results demonstrated that ARK5 expression was increased and positively correlated with metastasis, EMT-related markers and poor prognosis in patients with GC. Knockdown of ARK5 expression remarkably suppressed GC cells invasion and metastasis via regulating EMT, rather than proliferation in vitro and in vivo. And knockdown of ARK5 expression in GC cells resulted in the down-regulation of the mTOR/p70S6k signals, Slug and SIP1. Conclusion: The elevated ARK5 expression was closely associated with cancer metastasis and patient survival, and it seemed to function in GC cells migration and invasion via EMT alteration, together with the alteration of the mTOR/p70S6k signals, Slug and SIP1, thus providing a potential therapeutic target for GC