Solution, Cell and Animal Studies in Molecular MRI of Estrogen Receptor α

Adi Pais¹, Chidambaram Gunanathan¹, Inbal Biton¹, Raanan Margalit¹, David Milstein¹, Hadassa Degani¹

We have develop a non-invasive molecular MRI method for detecting, and investigating the level, activity and degradation of estrogen receptor alpha (ER) in breast cancer cells, tumors and metastases. Two novel contrast agents, composed of a gadolinuim-pyridiniumtetraacetic acid conjugated to 17-estradiol or to tamoxifen were synthesized and characterized for their solution chemistry as well as their biological activity and MRI parameters in cells and tumors. These agents demonstrated selective binding with high affinity to ER and significant enhancement of the water T1 and T2 relaxivity in ER+ as compared to ER- systems, and served to identify ER localization in vivo.