Development of Pathway Preferential Estrogens Affording Beneficial Metabolic and Vascular Actions without Reproductive Tissue Stimulation in Mice

There is great medical need for estrogens having favorable pharmacological profiles, supporting desirable activities for menopausal women such as metabolic and vascular protection but lacking stimulatory activities on the breast or uterus. Here, we report the development of structurally novel estrogens with favorable target tissue-selective estrogenic activity. Through a process of structural alteration of the hormone estradiol that preserves essential chemical and physical features of estradiol but greatly moderates its binding affinity for the estrogen receptors (ERs), we obtained Pathway Preferential Estrogens (PaPEs) capable of having interaction with ER that is sufficient to activate the extranuclear-initiated signaling pathway preferentially over the direct nuclear-initiated pathway. PaPE modulate a pattern of gene regulation and cellular and biological processes that result in essentially no stimulation of reproductive and mammary tissues and breast cancer cells, but have a favorable pattern of activity on metabolic tissues and the vasculature. The structural permutation process represents a novel approach to govern the balance in utilization of extranuclear vs. nuclear pathways of ER action to obtain tissue-selective/non-nuclear pathway-preferential estrogens, which should prove to be beneficial for postmenopausal hormone replacement. The approach may also have broad applicability for other members of the nuclear hormone receptor superfamily. 24 samples; inhibitor and time course experiments