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Encapsulation of metal nanoparticles by support-derived materials known as the classical strong metal–support interaction (SMSI) often happens upon thermal treatment of supported metal catalysts at high temperatures (≥500 °C) and consequently lowers the catalytic performance due to blockage of metal active sites. Here, we show that this SMSI state can be constructed in a Ru–MoO3 catalyst using CO2 hydrogenation reaction gas and at a low temperature of 250 °C, which favors the selective CO2 hydrogenation to CO. During the reaction, Ru nanoparticles facilitate reduction of MoO3 to generate active MoO3–x overlayers with oxygen vacancies, which migrate onto Ru nanoparticles’ surface and form the encapsulated structure, that is, Ru@MoO3–x . The formed SMSI state changes 100% CH4 selectivity on fresh Ru particle surfaces to above 99.0% CO selectivity with excellent activity and long-term catalytic stability. The encapsulating oxide layers can be removed via O2 treatment, switching back completely to the methanation. This work suggests that the encapsulation of metal nanocatalysts can be dynamically generated in real reactions, which helps to gain the target products with high activity.

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Acetylcholinesterase (ACHE) plays important roles in the cholinergic system, and its dysregulation is involved in a variety of human diseases. However, the roles and implications of ACHE in hepatocellular carcinoma (HCC) remain elusive. Here we demonstrate that ACHE was significantly down-regulated in the cancerous tissues of 69.2% of HCC patients, and the low ACHE expression in HCC was correlated with tumor aggressiveness, an elevated risk of postoperative recurrence, and a low survival rate. Both the recombinant ACHE protein and the enhanced expression of ACHE significantly inhibited HCC cell growth in vitro and tumorigenicity in vivo. Further study showed that ACHE suppressed cell proliferation via its enzymatic activity of acetylcholine catalysis and degradation. Moreover, ACHE could inactivate mitogenactivated protein kinase and phosphatidyl inositol-3 0 -phosphate kinase/protein kinase B pathways in HCC cells and thereby increase the activation of glycogen synthase kinase 3b and lead to b-catenin degradation and cyclin D1 suppression. In addition, increased ACHE expression could remarkably sensitize HCC cells to chemotherapeutic drugs (i.e., adriamycin and etoposide). Conclusion: For the first time, we describe the function of ACHE as a tumor growth suppressor in regulating cell proliferation, the relevant signaling pathways, and the drug sensitivity of HCC cells. ACHE is a promising independent prognostic predictor for HCC recurrence and the survival of HCC patients. These findings provide new insights into potential strategies for drug discovery and improved HCC treatment. (HEPATOLOGY 2011;53:493-503) H epatocellular carcinoma (HCC) is one of the most prevalent human malignancies worldwide and especially in East Asia and South Africa. 1The risk factors for HCC, such as aflatoxin B exposure and hepatitis B virus or hepatitis C virus infection, are well documented. However, the molecular pathogenesis of HCC remains to be comprehensively elucidated. Making matters worse, the particularly high rate of postsurgical recurrence (50%-70% at 5 years) renders this disease a major challenge that is highly refractory to conventional chemotherapy and radiation. 2Our previous study, which was based on a largescale complementary DNA transfection screening, showed that some neurotransmitter-related genes are involved in HCC cell proliferation or survival.3 Neurotransmitters have been for a long time considered to be confined to the nervous system, and reports about the presence of neurotransmitters in microorganisms, plants, and lower animals have emerged in recent years. 4 The transmitter acetylcholine (Ach) might function in the regulation of cell fates such as proliferation, differentiation, and the establishment of cell-cell