Abstract
A medium-throughput murine embryonic stem cell (mESC)-based high-content screening of 17000 small molecules for cardiogenesis led to the identification of a b-annulated 1,4-dihydropyridine (1,4-DHP) that inhibited transforming growth factor β (TGFβ)/Smad signaling by clearing the type II TGFβ receptor from the cell surface. Because this is an unprecedented mechanism of action, we explored the series' structure-activity relationship (SAR) based on TGFβ inhibition, and evaluated SAR aspects for cell-surface clearance of TGFβ receptor II (TGFBR2) and for biological activity in mESCs. We determined a pharmacophore and generated 1,4-DHPs with IC(50)s for TGFβ inhibition in the nanomolar range (e.g., compound 28, 170 nM). Stereochemical consequences of a chiral center at the 4-position was evaluated, revealing 10- to 15-fold more potent TGFβ inhibition for the (+)- than the (-) enantiomer. This stereopreference was not observed for the low level inhibition against Activin A signaling and was reversed for effects on calcium handling in HL-1 cells.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Activins / antagonists & inhibitors
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Activins / metabolism
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Animals
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Calcium / metabolism
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Cell Differentiation / drug effects*
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Cells, Cultured
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Dihydropyridines / chemical synthesis
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Dihydropyridines / pharmacology*
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Embryonic Stem Cells / cytology
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Embryonic Stem Cells / drug effects*
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Humans
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Mice
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Molecular Structure
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Myocytes, Cardiac / cytology
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Myocytes, Cardiac / drug effects*
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Protein Binding
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Protein Serine-Threonine Kinases / metabolism
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Quinolones / chemical synthesis
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Quinolones / pharmacology*
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Receptor, Transforming Growth Factor-beta Type II
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Receptors, Transforming Growth Factor beta / metabolism
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Signal Transduction / drug effects*
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Small Molecule Libraries / pharmacology*
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Stereoisomerism
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Structure-Activity Relationship
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Transforming Growth Factor beta / antagonists & inhibitors*
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Transforming Growth Factor beta / metabolism
Substances
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Dihydropyridines
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Quinolones
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Receptors, Transforming Growth Factor beta
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Small Molecule Libraries
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Transforming Growth Factor beta
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activin A
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ethyl 4-(4-tert-butylphenyl)-2-methyl-5-oxo-7-(n-propyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate
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Activins
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1,4-dihydropyridine
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Protein Serine-Threonine Kinases
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Receptor, Transforming Growth Factor-beta Type II
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Calcium