[Notch signaling pathway blocked by gamma-secretase inhibitor and its effect on the growth and apoptosis of SKOV3 cells].

OBJECTIVE: To determine the effect and mechanism of gamma-secretase inhibitor DAPT on the growth and apoptosis of human ovarian carcinoma SKOV3 cells. METHODS: The effect of gamma-secretase inhibitor DAPT was tested in vitro using SKOV3 cells. Its inhibition effect on cell proliferation was determined by CCK-8 assay. The cell apoptosis was detected by AO/EB double staining and flow cytometry. The expression of Notch1 mRNA and protein was detected by RT-PCR and Western blot. RESULTS: Compared with controls, 5 micromol/L, 10 micromol/L and 20 micromol/L of DAPT showed an effect of cell growth inhibition in a dose-dependent manner, with 19.87%, 28.38%, and 46.67% of 24 h inhibitory rates, respectively. Dose-dependent effect of DAPT on cell apoptosis was also evident, with (5.80 +/- 0.98)%, (12.96 +/- 4.99)%, (30.88 +/- 7.63)%, and (42.98 +/- 1.46)% apoptosis rates for the control, 5 micromol/L, 10 micromol/I, and 20 micromol/L DAPT groups, respectively. RT-PCR analysis demonstrated that the expression of Notch1 mRNA decreased significantly in the DAPT groups, with an inhibition rate of 10.23%, 20.50%, and 38.83% for the three DAPT groups, respectively. Western blot results demonstrated that the expression of Notch1 protein decreased significantly, with an inhibition rate of 12.89%, 27.47%, and 49.84% for the three DAPT groups, respectively. CONCLUSION: Gamma-secretase inhibitor DAPT can block Notch signaling pathway, inhibit proliferation, and induce apoptosis of SKOV3 cells through down-regulation of the expression of Notch1.

Epidemiology of human infection with avian influenza A(H7N9) virus in China, 2013-2017 / 中华流行病学杂志

Objective: To understand the epidemiological characteristics of human infection with avian influenza A (H7N9) virus in China, and provide evidence for the prevention and control of human infection with H7N9 virus. Methods: The published incidence data of human infection with H7N9 virus in China from March 2013 to April 2017 were collected. Excel 2007 software was used to perform the analysis. The characteristics of distribution of the disease, exposure history, cluster of the disease were described. Results: By the end of April 2017, a total of 1 416 cases of human infection with H7N9 virus were confirmed in China, including 559 deaths, the case fatality rate was 39.5%. In 2016, the case number was lowest (127 cases), with the highest fatality rate (57.5%). The first three provinces with high case numbers were Zhejiang, Guangdong and Jiangsu. The median age of the cases was 55 years and the male to female ratio was 2.3∶1. Up to 66% of cases had clear live poultry exposure history before illness onset, 31% of cases had unknown exposure history and only 3% of the cases had no live poultry exposure history. There were 35 household clusters (5 in 2013, 9 in 2014, 6 in 2015, 5 in 2016, 10 in 2017), which involved 72 cases, accounting for 5% of the total cases. Conclusions: The epidemic of human infection with H7N9 virus in China during 2013-2017 had obvious seasonality and spatial distribution. There was limited family clustering. Infection cases were mostly related to poultry contact.