17β-Estradiol Enhances Breast Cancer Cell Motility and Invasion via Extra-Nuclear Activation of Actin-Binding Protein Ezrin

Estrogen promotes breast cancer metastasis. However, the detailed mechanism remains largely unknown. The actin binding protein ezrin is a key component in tumor metastasis and its over-expression is positively correlated to the poor outcome of breast cancer. In this study, we investigate the effects of 17β-estradiol (E2) on the activation of ezrin and its role in estrogen-dependent breast cancer cell movement. In T47-D breast cancer cells, E2 rapidly enhances ezrin phosphorylation at Thr567 in a time- and concentration-dependent manner. The signalling cascade implicated in this action involves estrogen receptor (ER) interaction with the non-receptor tyrosine kinase c-Src, which activates the phosphatidylinositol-3 kinase/Akt pathway and the small GTPase RhoA/Rho-associated kinase (ROCK-2) complex. E2 enhances the horizontal cell migration and invasion of T47-D breast cancer cells in three-dimensional matrices, which is reversed by transfection of cells with specific ezrin siRNAs. In conclusion, E2 promotes breast cancer cell movement and invasion by the activation of ezrin. These results provide novel insights into the effects of estrogen on breast cancer progression and highlight potential targets to treat endocrine-sensitive breast cancers

Microstructure Characterizations in Composite Media Using Ultrasonic Tomography

While tomographic techniques for radiographic image reconstruction are well established, the development of similar methods for ultrasonic data lags far behind. One of the principal reasons for this difference, despite the general similarity of the problems, is the fact that x-rays travel in a straight path even in nonhomogeneous medium and acoustic waves will generally follow a curved ray path. This introduces an additional uncertainty (ray path) into the image reconstruction algorithm. A further complication for acoustic waves is anisotropy. In most conventional image reconstruction algorithms, it is assumed that each ray traversing a given pixel will interact with the material in exactly the same way. In anisotropic media, due to the directional dependence of material properties, this is no longer the case. In this work, we explore possible techniques for overcoming these limitations. In particular, a variational formulation, based on Fermat’s principle, is used to correct for ray bending effects. Further, with the aid of some simplifying assumptions, corrections for directional property variations due to anisotropy can be introduced into the reconstruction algorithm

The population dynamical implications of male-biased parasitism in different mating systems.

Although there is growing evidence that males tend to suffer higher levels of parasitism than females, the implications of this for the population dynamics of the host population are not yet understood. Here we build on an established ‘two-sex’ model and investigate how increased susceptibility to infection in males affects the dynamics, under different mating systems. We investigate the effect of pathogenic disease at different case mortalities, under both monogamous and polygynous mating systems. If the case mortality is low, then male-biased parasitism appears similar to unbiased parasitism in terms of its effect on the population dynamics. At higher case mortalities, we identified significant differences between male-biased and unbiased parasitism. A host population may therefore be differentially affected by male-biased and unbiased parasitism. The dynamical outcome is likely to depend on a complex interaction between the host's mating system and demography, and the parasite virulence