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Jie Liu, Fei Gao, Yue-Fang Liu, Hai-Ting Dou, Jia-Qi Yan, Zong-Min Fan and Zeng-Ming Yang

Embryo implantation and decidualization are key steps for successful reproduction. Although numerous factors have been identified to be involved in embryo implantation and decidualization, the mechanisms underlying these processes are still unclear. Based on our preliminary data, Prss56, a trypsin-like serine protease, is strongly expressed at implantation site in mouse uterus. However, the expression, regulation and function of Prss56 during early pregnancy are still unknown. In mouse uterus, Prss56 is strongly expressed in the subluminal stromal cells at implantation site on day 5 of pregnancy compared to inter-implantation site. Under delayed implantation, Prss56 expression is undetected. After delayed implantation is activated by estrogen, Prss56 is obviously induced at implantation site. Under artificial decidualization, Prss56 signal is seen at the primary decidual zone at the initial stage of artificial decidualization. When stromal cells are induced for in vitro decidualization, Prss56 expression is significantly elevated. Dtprp expression under in vitro decidualization is suppressed by Prss56 siRNA. In cultured stromal cells, HB-EGF markedly stimulates Prss56 expression through EGFR/ERK pathway. Based on promoter analysis, we also showed that Egr2 is involved in Prss56 regulation by HB-EGF. Collectively, Prss56 expression at implantation site is modulated by HB-EGF/EGFR/ERK signaling pathway and involved in mouse decidualization.

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Yen-Shen Lu, Pei-Yen Yeh, Shuang-En Chuang, Ming Gao, Min-Liang Kuo and Ann-Lii Cheng

Glucocorticoids (GCs) are commonly co-administered with cisplatin in the treatment of patients with carcinomas to prevent drug-induced allergic reaction, nausea and vomiting. Although GC receptor (GR) is ubiquitous in carcinoma cells and has been linked to signal transduction pathways pertinent to cell growth and apoptosis, little is known regarding the possible effect of GC on the chemosensitivity of carcinomas. Our previous study demonstrated that dexamethasone (DEX) enhances the cytotoxicity to cisplatin in a GR-rich human cervical carcinoma cell line, SiHa. In this study, we found that this cisplatin cytotoxicity-enhancing effect of DEX correlated well with its effect on abrogating the cisplatin-induced activation of nuclear factor kappa B (NF-κB). RU486, a structural homologue of DEX, partially reversed this cytotoxicity-enhancing effect of DEX, a finding consistent with the well-known partial reversing effect of RU486 on DEX-induced NF-κB suppression. Furthermore, expression of a dominant-negative truncated IκBα gene in SiHa cells completely abolished the cisplatin cytotoxicity-enhancing effect of DEX. Our data suggest that the specific action of DEX on GR may enhance the cytotoxicity of cisplatin in selected GR-rich cancer cells by suppressing NF-κB activation.

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Sheng-Gao Tang, Xiao-Yu Liu, Ji-Ming Ye, Ting-Ting Hu, Ying-Ying Yang, Ting Han and Wen Tan

Diabetes-induced injury of myocardium, defined as diabetic cardiomyopathy (DCM), accounts for significant mortality and morbidity in diabetic population. Alleviation of DCM by a potent drug remains considerable interests in experimental and clinical researches because hypoglycemic drugs cannot effectively control this condition. Here, we explored the beneficial effects of isosteviol sodium (STVNa) on type 1 diabetes-induced DCM and the potential mechanisms involved. Male Wistar rats were induced to diabetes by injection of streptozotocin (STZ). One week later, diabetic rats were randomly grouped to receive STVNa (STZ/STVNa) or its vehicle (STZ). After 11 weeks of treatment or 11 weeks treatment following 4 weeks of removal of the treatment, the cardiac function and structure were evaluated and related mechanisms were investigated. In diabetic rats, oxidative stress, inflammation, blood glucose and plasma advanced glycation end products (AGEs) were significantly increased, whereas superoxide dismutase 2 (SOD-2) expression and activity were decreased. STVNa treatment inhibited cardiac hypertrophy, fibrosis and inflammation, showed similar ratio of heart to body weight and antioxidant capacities almost similar to the normal controls, which can be sustained at least 4 weeks. Moreover, STVNa inhibited diabetes-inducted stimulation of both extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) signal pathways. However, blood glucose, plasma AGE and insulin levels were not altered by STVNa treatment. These results indicate that STVNa may be developed into a potent therapy for DCM. The mechanism underlying this therapeutic effect involves the suppression of oxidative stress and inflammation by inhibiting ERK and NF-κB without changing blood glucose or AGEs.