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Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
Published on: November 15, 2013
EPI-001 is a selective peroxisome proliferator-activated receptor-gamma modulator with inhibitory effects on androgen
Lucas J Brand1,2, Margaret E Olson3, Preethi Ravindranathan4
1Graduate Program in Microbiology, Immunology, and Cancer Biology, University of Minnesota, Minneapolis, MN, USA.
Abstract:
The androgen receptor (AR) is a driver of prostate cancer (PCa) cell growth and disease progression. Therapies for advanced PCa exploit AR dependence by blocking the production or action of androgens, but these interventions inevitably fail via multiple mechanisms including mutation or deletion of the AR ligand binding domain (LBD). Thus, the development of new inhibitors which act through non-LBD interfaces is an unmet clinical need. EPI-001 is a bisphenol A-derived compound shown to bind covalently and inhibit the AR NH2-terminal domain (NTD). Here, we demonstrate that EPI-001 has general thiol alkylating activity, resulting in multilevel inhibitory effects on AR in PCa cell lines and tissues. At least one secondary mechanism of action associated with AR inhibition was found to be selective modulation of peroxisome proliferator activated receptor-gamma (PPARγ). These multi-level effects of EPI-001 resulted in inhibition of transcriptional activation units (TAUs) 1 and 5 of the AR NTD, and reduced AR expression. EPI-001 inhibited growth of AR-positive and AR-negative PCa cell lines, with the highest sensitivity observed in LNCaP cells. Overall, this study provides new mechanistic insights to the chemical biology of EPI-001, and raises key issues regarding the use of covalent inhibitors of the intrinsically unstructured AR NTD.
Insights
EPI-001, a novel compound, inhibits prostate cancer (PCa) by targeting the androgen receptor (AR) N-terminal domain (NTD). This bisphenol A derivative offers a new therapeutic strategy for advanced PCa, overcoming resistance to current treatments.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- Androgen receptor (AR) drives prostate cancer (PCa) progression.
- Current therapies targeting AR ligand-binding domain (LBD) face inevitable resistance.
- Novel AR inhibitors acting via non-LBD interfaces are clinically needed.
Purpose of the Study:
- To investigate the novel AR inhibitor EPI-001's mechanisms of action.
- To evaluate EPI-001's efficacy in preclinical PCa models.
- To understand the chemical biology of EPI-001 for advanced PCa treatment.
Main Methods:
- Assessing EPI-001's covalent binding and thiol alkylating activity.
- Evaluating AR N-terminal domain (NTD) inhibition and downstream effects.
- Testing EPI-001's anti-proliferative effects on PCa cell lines and tissues.
- Investigating secondary mechanisms, including PPARγ modulation.
Main Results:
- EPI-001 covalently inhibits AR via its NTD, exhibiting general thiol alkylating activity.
- Multilevel AR inhibition includes reduced AR expression and suppression of transcriptional activation units (TAUs) 1 and 5.
- EPI-001 demonstrated anti-proliferative effects in both AR-positive and AR-negative PCa cell lines.
- Selective modulation of peroxisome proliferator activated receptor-gamma (PPARγ) was identified as a secondary mechanism.
Conclusions:
- EPI-001 represents a promising therapeutic agent targeting the AR NTD for advanced PCa.
- Its multilevel inhibitory effects and novel mechanism offer potential to overcome treatment resistance.
- Further research into covalent NTD inhibitors is warranted for PCa therapy.
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