Glargine is widely used as a long-acting insulin analogue in the treatment of diabetes mellitus. However, this insulin analogue has been recently suspected to be associated with an increased risk of cancer. The aim of this study was to investigate the influence of glargine on proliferation of breast adenocarcinoma cell line (MCF-7) and its possible mechanism. Effects of glargine and regular human insulin on the cell proliferation were tested in ER-positive MCF-7 cells by MTT assay. Apoptosis in MCF-7 cells was measured by flow cytometry. The protein levels of p-AKT, Bcl-2, and Bax were also determined by Western blotting and immunohistochemistry, respectively. The result showed that glargine (100, 200 nmol/l) stimulated proliferation of ER-positive MCF-7 cells compared with regular human insulin. At the same time, glargine decreased the percentage of early apoptosis in MCF-7 cells. Otherwise, glargine (100 nmol/l) stimulated the p-AKT in a time-dependent manner in MCF-7 cells. Furthermore, we found that glargine downregulated the level of Bax protein and upregulated that of Bcl-2 (p <0.05). These data show that glargine promote the proliferation of breast adenocarcinoma cells in vitro, probably by preventing apoptosis.
Many approaches have been examined to reversing multidrug resistance (MDR), but sub‐optimal target‐based strategies have limited their efficacy. Herein, we investigate microRNA (miR‐21) suppression on the doxorubicin (DOX)‐sensitisation of the DOX‐resistant (PC3/DOX) cell line in prostate cancer (PCa). Expression levels of miR‐21, P‐glycoprotein (P‐gp), MDR‐1 and PTEN evaluated in PC3/DOX cancer cells by qRT‐PCR and western blot analyses. The cytotoxic effects of transfected of miR‐21 were assessed by MTT assay for 72 hr. Rhodamine123 (Rh123) assay was employed to define the activity of P‐gp. Apoptosis was detected by Flow cytometry. As expected, miR‐21 was expressed highly in PC3/DOX cells (p < 0.05). It was shown that miRNA‑21 suppression considerably hindered PC3/DOX cell viability. miR‑21 suppression dramatically downregulated P‐gp expression and activity in DOX‐resistance cells and abolished MDR by an increment of intracellular accumulation of DOX in PC3/DOX cells (p < 0.05). PTEN is a key modulator of the PI3K/Akt/P‐gp cascade, which miR‐21 suppression led to the upregulation of PTEN and sequentially lower‐expression of P‐gp that reversed MDR. Also, miR‐21 repression enhanced the apoptosis rate of PC3/DOX cells. The findings of this paper contribute to the current understanding of the functions of miR‐21 in MDR‐reversing in PCa.
The relationship between shrub vegetation and precipitation is one important component of desert vegetation responses to climate change, but it has not been understood completely because of its complexity and nonlinearity. In this study, we used MODIS NDVI data and precipitation data from 2004 to 2012 to evaluate the relationship between the shrub vegetation and precipitation within Gurbantunggut Desert, Central Asia. Correlation analysis was employed to explore the relationship between NDVI and precipitation within growing season, within cross growing season, and on interannual scale. The results showed that NDVI could be classified into three temporal changing patterns within growing season, and NDVI was significantly correlated with the precipitation integrated by time durations and time lags within growing season; NDVI was significantly correlated with precipitation in the early growing season, but this relationship was not so obvious in the middle or late growing season; and the NDVI variational patterns depended on mean annual precipitation and the distribution of precipitation throughout the year. Precipitation had significant influence on shrub vegetation within Gurbantunggut Desert. Our findings provide basic knowledge for the relationship between precipitation and shrub vegetation, and it is helpful to understand how the desert vegetation responds to climate change in the future.
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