Norepinephrine attenuates CXCR4 expression and the corresponding invasion of MDA-MB-231 breast cancer cells via ß2-adrenergic receptors.

OBJECTIVE: The growing evidence from laboratory and clinical studies has shown that the stress hormone, norepinephrine, and chronic stress promote tumor progression in a variety of tumor types. Chemokines and chemokine receptors have been shown to play a pivotal role in tumor progression. Recently, norepinephrine was reported to have a significant effect on macrophage migration by altering the expression of the chemokine receptor CCR2. MATERIALS AND METHODS: We investigated whether chemokines and their receptors are involved in the effects of norepinephrine on breast cancer. First, we used microarray analyses to detect the alteration of 128 chemotactically relevant genes after MDA-MB-231 cells were treated for 12 h with 100 µM norepinephrine. The CXCR4 gene demonstrated the greatest response to norepinephrine treatment, with a reduction of transcription of 95.7%, and was the focus of subsequent investigations. Real-time reverse transcription-PCR was used to determine the level of CXCR4 transcription after treatment with norepinephrine at various concentrations and for different durations. RESULTS: The results revealed that norepinephrine reduced CXCR4 transcription in a dose-dependent manner. Norepinephrine was also found to exert a negative effect on CXCR4 translational expression, as evidenced by a 44 ± 1.7% reduction in expression after a 12-h treatment with 10 µM norepinephrine. A Matrigel assay demonstrated a 51.3 ± 9.1% reduction in the number of MDA-MB-231 cells driven to migrate by CXCR4. Finally, we found the specific ß2-adrenergic antagonist, ICI 118,551, eliminated the impact of norepinephrine on CXCR4 expression. CONCLUSIONS: Norepinephrine attenuates CXCR4 expression and the corresponding invasion of MDA-MB-231 tumor cells via the ß2-adrenergic receptor. The complexity of the ß2-adrenergic receptor signaling pathway might contribute to these unexpected observations in our research, and this justifies further investigation into the intricate mechanisms involved.

Study on the treatment of the p15 gene combined with Bcr-abl-specific siRNA and STI571 for chronic myeloid leukemia.

The aim of this study was to investigate the effect of the p15 gene combined with Bcr-abl-specific siRNA and STI571 on the proliferation, cell cycle and apoptosis of K562 chronic myeloid leukemia cells. Using the gene sequence results, we amplified the p15 gene from normal peripheral blood by RT-PCR, and constructed a p15-pcDNA3.1 vector. The K562 cell line with G418 resistance was screened, synthesized and transfected for bcr-abl gene fusion point for 21-nt siRNA. In p15-pcDNA3.1-K562 cells, the growth rate was slower than that of the control K562 cells, G0/G1-phase was increased and S-phase was decreased significantly. In the siRNA group, bcr-abl fusion gene expression was significantly decreased in K562 cells accompanied by the downregulation of BCL-xL protein expression and G1-phase arrest. Cell survival rate was significantly decreased compared with the sole p15-K562 cell group and the sole RNA interference-K562 cell group. In the combination of p15-pcDNA3.1-K562 cells with STI571, the proportion of apoptosis was significantly increased and the cell survival rate was significantly decreased compared with the p15-K562 cell group and STI571-K562 cell group. siRNA at 30 pM combined with 0.5 µM STI571 promoted apoptosis compared with sole application. The p15 gene combined with siRNA had a synergistic effect on the inhibition of proliferation and the induction of apoptosis in K562 cells. Exogenous p15 protein expression combined with STI571 appeared to have a synergistic effect on proliferation inhibition and apoptosis induction in K562 cells. The combination of low-dose RNA interference with STI571 showed a synergistic effect in inducing apoptosis.

Characterization of runoff from various urban catchments at different spatial scales in Beijing, China.

In order to investigate the characterization of runoff in storm sewer from various urban catchments, three monitoring systems at different spatial scales have been installed separately. They have been held since July 2010 in urban area of Beijing (China). The monitoring data revealed that chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and NH(3)-N values significantly exceed the Class V surface water quality standard developed by Ministry of Environmental Protection of the People's Republic of China (MEP). A surface solids buildup and wash off model for small watershed was adopted to analyze and discuss the process of a runoff pollutant discharge. More than a half of pollutant parameters presented a good fit to the model. However, a slightly worse-fit to the wash off model appeared in less than half of the data. Due to the influence of sewer sediments, sewer system characteristics, catchment characteristics, and other reasons, first flush was seldom observed in storm sewer runoff from these three survey areas. Meanwhile, the correlation between TSS and any other pollutant was analyzed according to cumulative load of pollutants in runoff events. An event mean concentrations (EMCs) approach was adopted to quantify the pollution of runoff. EMCs of various pollutants in storm sewer runoff between different rainfall events were slightly higher than the typical values observed in similar areas at home and abroad, according to other studies reported in literature. Based on quantitative analysis, it can be concluded that urban non-point source pollution is recognized as the major causes of quality deterioration in the receiving water bodies. This is after the point source pollution has been controlled substantially in Beijing. An integrated strategy, which combines centralized and decentralized control, along with the conditions of meteorology, hydrology, urban planning, existing drainage system, etc., will be an effective and economic approach to urban runoff pollution control.