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AGN193109 is a highly effective antagonist of retinoid action in human ectocervical epithelial cells
C Agarwal1, R A Chandraratna, A T Johnson
1Department of Physiology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970 USA.
Abstract:
Retinoids are important physiological agents that regulate epithelial cell differentiation and proliferation. The importance of these agents in regulating growth, development, and differentiation has led to a search for new retinoid agonists and antagonists. In the present manuscript we show that AGN193109, a retinoid analog, is an efficient antagonist of retinoid action in human cervical epithelial cells. Treatment of ECE16-1 cells with natural or synthetic retinoids reduces cytokeratin K5, K6, K14, K16, and K17 levels, increases cytokeratin K7, K8, and K19 levels, increases retinoic acid receptor-beta (RAR beta) mRNA levels, suppresses proliferation, and alters cell morphology. Co-treatment with AGN193109 prevents these responses. Half-maximal and maximal antagonism is observed at a molar ratio of AGN193109: retinoid agonist of 1:1 and 10:1, respectively. When administered alone AGN193109 has no agonist activity. Thus, AGN193109, which binds to RAR alpha, RAR beta, and RAR gamma with Kd values = 2,2, and 3 nm, respectively, but is unable to bind to the retinoid X receptors, is a highly active antagonist of retinoid action in ECE16-1 cells.
Insights
AGN193109 effectively blocks retinoid signaling in human cervical cells. This retinoid antagonist prevents changes in cytokeratin levels, cell proliferation, and morphology, showing no agonist activity itself.
Area of Science:
- Cell Biology
- Molecular Pharmacology
- Dermatology
Background:
- Retinoids are crucial for regulating epithelial cell growth and differentiation.
- Identifying specific retinoid agonists and antagonists is vital for therapeutic development.
- Human cervical epithelial cells (ECE16-1) serve as a model for studying retinoid effects.
Purpose of the Study:
- To investigate the antagonist properties of the retinoid analog AGN193109.
- To determine the efficacy of AGN193109 in blocking retinoid actions in human cervical epithelial cells.
- To characterize the binding affinity and specificity of AGN193109 to retinoic acid receptors (RARs).
Main Methods:
- Treatment of ECE16-1 cells with retinoids and/or AGN193109.
- Analysis of cytokeratin expression levels (K5, K6, K14, K16, K17, K7, K8, K19) via quantitative assays.
- Measurement of retinoic acid receptor-beta (RAR beta) mRNA levels.
- Assessment of cell proliferation and morphological changes.
- Determination of binding affinities (Kd values) of AGN193109 to RAR alpha, RAR beta, and RAR gamma.
Main Results:
- Retinoid treatment altered cytokeratin profiles, increased RAR beta mRNA, suppressed proliferation, and changed cell morphology.
- Co-treatment with AGN193109 completely prevented these retinoid-induced effects.
- AGN193109 demonstrated potent antagonism at molar ratios of 1:1 (half-maximal) and 10:1 (maximal).
- AGN193109 exhibited no agonist activity when administered alone.
- AGN193109 binds to RAR alpha, RAR beta, and RAR gamma with high affinity (Kd values of 2, 2, and 3 nM, respectively) but does not bind to retinoid X receptors.
Conclusions:
- AGN193109 is a highly effective antagonist of retinoid action in human cervical epithelial cells.
- The compound selectively targets RARs, offering a specific tool for modulating retinoid signaling pathways.
- AGN193109 represents a promising candidate for further research in conditions involving dysregulated retinoid signaling.