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Nasopharyngeal carcinoma (NPC) is a common cancer among the Chinese population in the southern part of China. The incidence of this cancer drops markedly in northern China. A 6-to 24-fold difference exists between southern and northern Chinese. To investigate the early genetic events involved in the development of this cancer, we have examined loss of heterozygosity (LOH) on chromosome 9p, being one of the most frequent genetic alterations in NPC, in nasopharyngeal tissues including normal epithelia (NP), dysplastic lesions (DNP) and invasive carcinoma (NPC) from high-risk and low-risk regions. We found similar frequencies of 9p LOH in NPC from high-risk (77.8%) and low-risk (63.6%) regions (p ‫؍‬ 0.43). In contrast, 45% of normal nasopharyngeal epithelia from the high-risk region showed 9p LOH, while none of the NP from the low-risk region showed such abnormalities (p ‫؍‬ 0.002). Deletions of chromosome 9p were found in 66.7% dysplastic nasopharyngeal lesions. These findings suggest that LOH of chromosome 9p is an early event in the tumorigenesis of NPC. The increased risk of NPC in southern Chinese may be related to early loss of genetic materials as indicated by 9p LOH in the NP from high-and low-risk regions. We also reported previously that EpsteinBarr virus (EBV) latent infection was present in all high-grade DNP and NPC but not in any NP from fetuses or normal adults. Thus, early genetic alterations such as 9p LOH may take place prior to EBV latent infection and expand clonally thereafter.

Dissimilatory metal reducing bacteria (DMRB) are capable of extracellular electron transfer (EET) to insoluble metal oxides, which are used as external electron acceptors by DMRB for their anaerobic respiration. The EET process has important contribution to environmental remediation mineral cycling, and bioelectrochemical systems. However, the low EET efficiency remains to be one of the major bottlenecks for its practical applications for pollutant degradation. In this work, Shewanella oneidensis MR-1, a model DMRB, was used to examine the feasibility of enhancing the EET and its biodegradation capacity through genetic engineering. A flavin biosynthesis gene cluster ribD-ribC-ribBA-ribE and metal-reducing conduit biosynthesis gene cluster mtrC-mtrA-mtrB were coexpressed in S. oneidensis MR-1. Compared to the control strain, the engineered strain was found to exhibit an improved EET capacity in microbial fuel cells and potentiostat-controlled electrochemical cells, with an increase in maximum current density by approximate 110% and 87%, respectively. The electrochemical impedance spectroscopy (EIS) analysis showed that the current increase correlated with the lower interfacial charge-transfer resistance of the engineered strain. Meanwhile, a three times more rapid removal rate of methyl orange by the engineered strain confirmed the improvement of its EET and biodegradation ability. Our results demonstrate that coupling of improved synthesis of mediators and metal-reducing conduits could be an efficient strategy to enhance EET in S. oneidensis MR-1, which is essential to the applications of DMRB for environmental remediation, wastewater treatment, and bioenergy recovery from wastes.

The positive roles of the Wnt/β-catenin pathway in osteoblast differentiation and bone mineral density (BMD) maintenance have been clearly demonstrated in both animal experiments and clinical investigations. CXXC finger protein 5 (CXXC5), a recently identified negative regulator of the Wnt/β-catenin pathway, showed altered cellular localization and function, which were dependent on the cell type in previous studies. However, the in vivo function of CXXC5 has not been clearly investigated yet. Here, we characterized CXXC5 as a negative regulator of osteoblast differentiation and bone formation. Deficiency of CXXC5 resulted in elevated BMD in mice without any severe gross developmental abnormalities. CXXC5 exerted a negative-feedback effect on the Wnt/β-catenin pathway via Wnt-dependent binding to Dishevelled (Dvl) during osteoblast differentiation. Suppression of the Dvl-CXXC5 interaction using a competitor peptide resulted in the activation of the Wnt/β-catenin pathway and osteoblast differentiation, and accelerated thickness growth of ex vivo-cultured calvariae. Overall, CXXC5 is a negative-feedback regulator induced by Wnt/β-catenin signaling that inhibits osteoblast differentiation and bone formation via interaction with Dvl. Cell Death and Differentiation (2015) 22, 912-920; doi:10.1038/cdd.2014.238; published online 30 January 2015Bone is an extremely dynamic tissue at the microscopic level. A dynamic process, called bone remodeling, takes place seamlessly in the bone to repair microdamage and to replace old bone with new bone. 1 The resorption of old bone and the formation of new bone must be in balance to maintain homeostasis and a constant mass of bone. Osteoblasts have been identified as an essential factor in regulation of the bone remodeling process, which produce bone matrix and differentiate into osteocytes for bone formation, as well as regulate differentiation and activation of osteoclasts for bone resorption. 2 The Wnt/β-catenin pathway is receiving increased attention as a main regulatory pathway for osteoblast differentiation. [2][3][4] Wnt-dependent nuclear accumulation of an effector protein of the pathway, β-catenin, is a major trigger of osteoblast differentiation and bone formation. 2 Many other intracellular and extracellular components of the Wnt/β-catenin pathway are known to regulate osteoblast differentiation. 4 Especially two negative regulators of this pathway, Dickkopf 1 and sclerostin, have been highlighted as osteoblast and osteocytespecific negative regulators of bone formation. 5 CXXC finger protein 5 (CXXC5) is a member of a small protein family in which the members contain CXXC-type zincfinger domain. 6 However, unlike other members of this family, CXXC5 lacks a KFGG motif, which is essential for non-methylated CpG recognition that regulates chromatin remodeling. 7 CXXC5 localizes to the cytosol or nucleus depending on particular cell type in different tissues. Localization of CXXC5 in the nucleus was observed in promyelocytic leukemia cells. 7 CXXC5 has a role as a nuclear t...

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