UC Irvine

The role of estrogen receptors (ER) is highly dependent on their sub-cellular localization and concentration. Here, we propose an approach to detect molecular transport, diffusion and localization of the estrogen receptor  by measuring the time cross-correlation between pairs of locations and the average number of molecules by means of fluorescence fluctuations in mammalian cells. From this data we find that there is concentration dependence for the localization of the estrogen receptor and that 17--Estradiol (E2) reduces the apparent diffusion of the receptor. In addition, we use fluorescence lifetime imaging, a label-free, non-invasive imaging method to demonstrate changes in the glucose metabolic pathway in ER-positive breast cancer cells. We observe a higher free to bound NADH ratio in high glucose conditions, reflecting and increased glycolysis/oxidative phosphorylation ratio. Furthermore, E2 is able to potentiate metabolic adaptation and cell viability depending on the glucose availability. Taking advantage of a wide array of available biophysical analysis techniques may provide additional useful information for estrogen receptors and in breast cancer research.