The two known estrogen receptors, ERa and ERb, are the products of different genes on separate chromosomes. Of these, ERa has been the most extensively studied, and its expression in breast cancer determines the ER+ phenotype. ERb, on the other hand, was discovered only recently and its role in breast cancer pathology remains unclear. ERb inhibits E2-induced proliferation of T47D breast cancer cells in addition to decreasing the expression of cell cycle related genes. Clinical studies have shown a positive correlation between ERâ expression with disease-free survival and overall survival in breast cancer patients. ERb activation with a selective ERb agonist could antagonize the stimulating activity of the ERa in breast cancer cells, and such an ERb agonist could help overcome acquired resistance. Therefore, this work began a search for such agents.
A one-pot hydrozirconation-transmetallation-aldimine addition sequence that leads to allylic amides, homoallylic amides and C-cyclopropylalkylamides was significantly accelerated by microwave technology and used for library preparation. The conventional methodology provided a first generation discovery library. A potentially antiestrogenic compound was identified in a transcriptional screening assay from this library, C-cyclopropylalkylamide 26a (O-ethyl-N-{2-[(1S*,2R*)-2-{(R*)[(diphenylphosphinoyl)amino](phenyl)methyl}cyclopropyl]-ethyl}-N-[(4-methylphenyl)sulfonyl]carbamate; a.k.a. CK1-183).
Following up on these findings and with the goal to expand the scope of the synthesis methodology, a second generation library of allylic amides and C-cyclopropylalkylamides was prepared. The new library was screened in a fluorescence polarization based homogenous in vitro assay at ERa, and hits were further evaluated in cell-based assays. Three new C-cyclopropylalkylamides, 37c, 37a and 39c, were identified with improved potency over the lead agent 26a against 17b-estradiol (E2) stimulated MCF-7 cells.
This second generation library was screened against both ERs. The screening results served to build an SAR model of allylic amides and C-cyclopropylalkylamides at ERa and ERb.
A hit from the ERa screen, C-cyclopropylalkylamide 37d (N-(R*)-(((1R*,2R*)-2-butylcyclopropyl)-(4-(phenyl)phenyl)methyl)benzamide), contained a biphenyl core and served as a starting point for the design and synthesis of a third generation of C-cyclopropylalkylamide ER targeting agents.
Biphenyl C-cyclopropylalkylamides represent novel structural scaffolds for design and synthesis of ERa and ERb targeting agents and a novel avenue for selective estrogen receptor modulator (SERM) development.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-12142005-095556 |
| Date | 20 December 2005 |
| Creators | Janjic, Jelena M. |
| Contributors | Billy W. Day, PhD, Michael Mokotoff, PhD, Wen Xie, MD PhD, Peter Wipf, PhD, Mark Nichols, PhD |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-12142005-095556/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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