Ernst Schering Foundation symposium proceedings最新文献

The progesterone receptor (PR) is an important regulator of female reproduction. Consequently, PR modulators have found numerous pharmaceutical utilities in women's reproductive health. In the process of identifying more receptor-specific and tissue-selective PR modulators, we discovered a novel nonsteroidal, 6-aryl benzoxazinone compound, PRA-910, that displays unique in vitro and in vivo activities. In a PR/PRE reporter assay in COS-7 cells, PRA-910 shows potent PR antagonist activity with an IC50 value of approximately 20 nM. In the alkaline phosphatase assay in the human breast cancer cell line T47D, PRA-910 is a partial progesterone antagonist at low concentrations and is also an effective PR agonist at higher concentrations (EC50 value of approximately 700 nM). PRA-910 binds to the human PR with high affinity (Kd = 4 nM) and was previously shown to exhibit greater than 100-fold selectivity for the PR versus other steroid receptors. In the adult ovariectomized rat, PRA-910 is a potent PR antagonist. It inhibits progesterone-induced uterine decidual response with an ED50 value of 0.4 mg/kg, p.o., and reverses progesterone suppression of estradiol-induced complement C3 expression with potency similar to RU-486. In the nonhuman primate, however, PRA-910 is a PR agonist. The effect on endometrial histology strongly resembles that of progesterone. This unique compound also suppresses estradiol-induced epithelial cell proliferation and both estrogen and progesterone receptor expression in the uterine endometrium as a PR agonist would. In summary, PRA-910 is a structurally and biologically novel selective PR modulator with either PR agonist or antagonist activity, depending on context, concentration, and species.

The importance of the progesterone receptor (PR) in transducing the progestin signal is firmly established in female reproductive and mammary gland biology; however, the coregulators preferentially recruited by PR in these systems have yet to be comprehensively investigated. Using an innovative genetic approach, which ablates gene function specifically in murine cell-lineages that express PR, steroid receptor coactivator 2 (SRC-2, also known as TIF-2 or GRIP-1) was shown to exert potent coregulator properties in progestin-dependent responses in the uterus and mammary gland. Uterine cells positive for PR (but devoid of SRC-2) led to an early block in embryo implantation, a phenotype not shared by knockouts for SRC-1 or SRC-3. In the case of the mammary gland, progestin-dependent branching morphogenesis and alveologenesis failed to occur in the absence of SRC-2, thereby establishing a critical coactivator role for SRC-2 in cellular proliferative programs initiated by progestins in this tissue. Importantly, the recent detection of SRC-2 in both human endometrium and breast suggests that this coregulator may provide a new clinical target for the future management of female reproductive health and/or breast cancer.

The directed evolution of functional enzymes as catalysts in organic reactions has emerged as a powerful method of protein engineering. This includes the directed evolution of enantioselective enzymes as pioneered by the author. In recent years the challenges in this new area of asymmetric catalysis has shifted to solving the problem of probing protein sequence space more efficiently than before. Iterative saturation mutagenesis (ISM) is one way of addressing this crucial question. This chapter reviews the concept of ISM and its application in controlling the enantioselectivity and thermostability of enzymes, specifically those that have an organocatalytic mechanism. Illustrative examples include the directed evolution of lipases, Baeyer-Villigerases and epoxide hydrolases.

The current scope and limitations of organocatalytic reactions and the consequences for the strategic planning of natural product syntheses are discussed. Examples from our group include the total synthesis of UCS1025A and lepidopteran sex pheromones.

Metabolic phenotyping in large-scale population studies can yield crucial information regarding the impact and interaction of genetic and environmental factors with regard to the prevalence and risk of chronic diseases. Spectroscopic technologies such as nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) can be used to generate multi-parameter profiles of biological samples and together with automated sample delivery and mathematical modelling systems, can be used as a high throughput screening tool. The adaptation of these metabolic profiling tools from pre-clinical studies in animal models to population studies in man is explored and an overview of the current and future roles of metabolic phenotyping is described, including the idea of "Metabolome Wide Association Screening" focussing on key disease areas such as cardiovascular disease and metabolic syndrome, cancers and neurodegeneration.