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Zhao Q.,Shandong University | Zhao Q.,Shandong Province Key Laboratory of Infection and Immunity | Zhao M.,Shandong University | Dong T.,Shandong University | And 12 more authors.
Journal of Cellular Biochemistry | Year: 2015

The pathogenesis of gastric cancer is not completely understood. Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2) has recently been identified as a novel negative regulator gene of the immune system, and studies in mice and humans have suggested its inhibitory action in both inflammation and cancer. In this study, we examined the expression levels of TIPE2 in human gastric cancer tissues and also samples of paraneoplastic control tissue, and found that TIPE2 expression was reduced in gastric cancer. To investigate the role of TIPE2 in gastric cell carcinogenesis, a TIPE2 plasmid was introduced into gastric cell lines and TIPE2 function was examined. Colony-forming assays showed that restoration of TIPE2 expression in gastric cells significantly suppressed cell proliferation. Analysis by flow cytometry showed that the number of cells in the S phase of the cell cycle was reduced concomitant with TIPE2 expression, and cell apoptosis was maintained at a low level. Microarray and western blot analyses revealed that TIPE2 selectively up-regulated N-ras and p27 expression. The role of p27 in mediating TIPE2-associated cell growth inhibition was verified by a p27 siRNA interference assay. In this study, we proved that TIPE2 is an inhibitor of gastric cancer cell growth, and suggest that TIPE2 might promote a p27-associated signaling cascade that leads to restored control of the cell cycle and cell division. Our results provide a new molecular mechanism by which TIPE2 may regulate proliferation of gastric cells. J. Cell. Biochem. 116: 1121-1129, 2015. © 2015 Wiley Periodicals, Inc.

Shi-Li L.,Shandong University | Shi-Li L.,Shandong Province Key Laboratory of Infection and Immunity | Shou-Zhen C.,Shandong University | Shou-Zhen C.,Shandong Province Key Laboratory of Infection and Immunity | And 7 more authors.
Fenxi Huaxue/ Chinese Journal of Analytical Chemistry | Year: 2013

Quantitative detection of small molecules by a photoelectrochemical system was demonstrated in a competitive assay for biotin. The system for the determination of Biotin was employed by using ruthenium tris(bipyridine) (Ru-bpy) as the label, oxalate as the sacrificial electron donor to recycle the label, and tin oxide nanoparticle as the semiconductor electrode. Upon irradiation with 470 nm light, electrons of Ru-bpy were promoted to the excited state, and then injected into the conduction band of the tin oxide semiconductor, thus producing photocurrent signal. The oxidized Ru-bpy was reduced back to its original state by oxalate in solution, and was used again in the next cycle of signal generation. In the competitive assay of biotin, avidin was adsorbed passively on the tin oxide surface as the recognition element. Adsorbed protein was found to be stable under assay conditions, and reached maximum surface coverage when the concentration of avidin solution for adsorption was 0.5 g L-1 or higher. A mixed solution of 1 μM tracer and various concentrations of biotins were reacted with surface-immobilized avidin. As biotin concentration was increased, less tracer molecules bound to avidin, leading to a reduction in its photocurrent signal. A detection limit of 8 μg L-1 biotin was obtained in the competitive assay. The method can be easily extended to the detection of competitive immunoassays for organic chemicals. Copyright © 2013, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences.

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