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Updated: Oct 18, 2025
Malachite Green Assay for the Discovery of Heat-Shock Protein 90 Inhibitors
Published on: January 20, 2023
Effect of EPA on Hsp90 and GRα protein expression in multiple myeloma drug-resistant cells
Shenghao Wu1, Yuemiao Chen2, Xueshuang Wang2
1Department of Hematology, The Second Affiliated Hospital of Shanghai University (The Dingli Clinical Institute of Wenzhou Medical University, Wenzhou Central Hospital), No.252 East Baili Road, Lucheng District, Wenzhou, 325000, Zhejiang Province, China. wushenghao30@gmail.com.
Background:
Approximately 20% of MM patients harbor glucocorticoid (GC) resistance and are not responsive to therapeutic effect. Chaperoneheat-shock proteins Hsp90 is needed for ligand docking, The imbalance of Hsp90/GRα (glucocorticoid receptor α) may be an important cause of GC resistance. Recent studies have indicated that EPA could repress cancer cell growth by regulating critical influential factors in progression of cancer, consisting of resistance to drugs, chemosensitivity. The aim of the present study was to test the cytotoxic effects of EPA alone or EPA + Dexamethasone in dexamethasone-resistant MM cell (MM.1R) and investigate whether DHA can induce apoptosis and reverse acquired glucocorticoid resistance in dexamethasone-resistant MM cell (MM.1R).
Methods:
Cell Counting Kit-8 (CCK-8) was used to detect the proliferation of MM.1R cells after treating with EPA alone and EPA combined with DEX. Mitochondrial membrane potential was measured by flow cytometry and GRα and Hsp90 protein expression were assessed by western blot analysis.
Results:
EPA alone was able to inhibit cell proliferation as evidenced by CCK-8 assay and the tumor growth was remarkably suppressed by EPA + Dexamethasone, Cell apoptosis after EPA treatment was obviously observed by Flow cytometry analysis of the mitochondrial membrane potential. Analysis of Hsp90 and GRα proteins in MM.1R cells incubated with EPA revealed down-regulation of Hsp90 and up-regulation of GRα. Accordingly, the Hsp90/GRα ratio was significantly decreased with the increase of EPA concentration.
Conclusions:
EPA might be used as a new effective treatment for reversal of glucocorticoid-resistance in multiple myeloma.
Insights
Eicosapentaenoic acid (EPA) may reverse glucocorticoid resistance in multiple myeloma (MM) by down-regulating Hsp90 and up-regulating the glucocorticoid receptor (GRα). This suggests EPA as a potential novel therapeutic for MM patients resistant to standard treatments.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Glucocorticoid (GC) resistance affects approximately 20% of multiple myeloma (MM) patients.
- Imbalance in heat-shock protein 90 (Hsp90) and glucocorticoid receptor alpha (GRα) may contribute to GC resistance.
- Eicosapentaenoic acid (EPA) has shown potential in repressing cancer cell growth and influencing drug resistance.
Purpose of the Study:
- To evaluate the cytotoxic effects of EPA, alone and with dexamethasone (DEX), on dexamethasone-resistant MM cells (MM.1R).
- To investigate EPA's ability to induce apoptosis and reverse acquired GC resistance in MM.1R cells.
Main Methods:
- Cell Counting Kit-8 (CCK-8) assay for cell proliferation.
- Flow cytometry to measure mitochondrial membrane potential and assess apoptosis.
- Western blot analysis for Hsp90 and GRα protein expression.
Main Results:
- EPA alone inhibited MM.1R cell proliferation; EPA combined with DEX significantly suppressed tumor growth.
- EPA treatment induced apoptosis in MM.1R cells, indicated by changes in mitochondrial membrane potential.
- EPA down-regulated Hsp90 and up-regulated GRα, decreasing the Hsp90/GRα ratio in a dose-dependent manner.
Conclusions:
- EPA demonstrates potential as a novel therapeutic agent for reversing glucocorticoid resistance in multiple myeloma.
- The mechanism involves modulating the Hsp90/GRα balance, crucial for GC sensitivity.
