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Updated: May 8, 2026
Malachite Green Assay for the Discovery of Heat-Shock Protein 90 Inhibitors
Published on: January 20, 2023
In silico design of small peptide-based Hsp90 inhibitor: a novel anticancer agent
Uday Kumar Gupta1, Sailendra Mahanta, Subhankar Paul
1Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela, Orissa 769 008, India.
Background:
Breast cancer is a common disease found among women and has been a serious issue for last two decades. Although various kinds of heat shock proteins (Hsp's) have strong implications in cancer, heat shock protein 90 alpha (Hsp90α) has attracted highest attention for the cause and therapy of breast cancer. It regulates approximately 200 numbers of proteins known as client proteins including large number of oncoproteins found to be upregulated in many cancer cells. Therefore, inhibition of Hsp90α is a common therapeutic approach pursued in many cancers. However, Hsp90α inhibitors both natural and chemical, reported so far are plagued with problems related to toxicity, bioavailability and solubility including geldanamycin, the most common Hsp90α inhibitor. Therefore, search for a suitable Hsp90α inhibitor is an urgent need.
Hypothesis:
Here we hypothesize that Hsp organizing protein (HOP) helps in the interaction of Hsp90α with Hsp70, which is the key to appropriate chaperonin function of Hsp90α and therefore, inhibiting such interaction might lead to the disruption of Hsp90α-client protein complex, which in turn destabilize and degrade client proteins. We further hypothesize that considering the residues involved in the reaction we can design novel peptide based Hsp90α inhibitor.
Experimental Design:
In our present in silico investigation, we hypothesized that the chaperone function of Hsp90α requires the complex formation with HOP and co-chaperones Hsp70, Hsp40. We performed the docking interaction between Hsp90α and HOP. Based on the key residues involved in the interaction between Hsp90α and HOP, we designed ten peptides having twelve amino acids each. We docked the designed peptides with Hsp90α using docking software Hex 6.1 and the peptide with the highest binding energy value was identified. Using the online FOLDAMYLOID program, we assessed their amyloidogenic propensity. Amylodegenic properties were also considered and based on that five different peptides were again redesigned. Several modifications incorporated onto the peptide led to the design of five different peptides.
Results:
The peptide with the lowest amyloidogenic properties and highest binding energy for Hsp90α was the criteria laid for selection as an Hsp90α-inhibitor. Its potential to bind Hsp90α and disrupt Hsp90α-HOP complex was subsequently investigated using both wild as well as mutant p53 as a client protein.
Conclusion:
The predicted binding energy values showed that our designed novel peptide demonstrated strong binding affinity for Hsp90α. Subsequently, the binding affinity of Hsp90α for mutant p53 was shown to be reduced substantially indicating a strong inhibitory potential of the designed peptide PEP73 (INSAYKLKYARG) for Hsp90α.
Insights
Researchers designed a novel peptide inhibitor targeting heat shock protein 90 alpha (Hsp90α) to disrupt cancer cell mechanisms. This peptide shows strong binding affinity and potential for breast cancer therapy, addressing limitations of current inhibitors.
Area of Science:
- Molecular biology
- Biochemistry
- Drug discovery
Background:
- Heat shock protein 90 alpha (Hsp90α) is crucial for cancer cell regulation and a therapeutic target.
- Existing Hsp90α inhibitors face challenges with toxicity, bioavailability, and solubility.
- Novel therapeutic strategies are needed to effectively inhibit Hsp90α in cancer treatment.
Purpose of the Study:
- To investigate the role of Hsp organizing protein (HOP) in Hsp90α chaperone function.
- To design novel peptide-based inhibitors targeting the Hsp90α-HOP interaction.
- To develop a more effective and safer Hsp90α inhibitor for cancer therapy.
Main Methods:
- In silico investigation of Hsp90α and HOP interactions.
- Design and synthesis of ten peptide inhibitors based on key interaction residues.
- Molecular docking using Hex 6.1 software to assess binding energy.
- Evaluation of amyloidogenic propensity using FOLDAMYLOID program.
- Redesign of peptides based on binding energy and amyloidogenicity.
Main Results:
- A novel peptide, PEP73, demonstrated high binding affinity for Hsp90α.
- The designed peptide effectively disrupted the Hsp90α-HOP complex.
- Binding of Hsp90α to its client protein, mutant p53, was significantly reduced.
Conclusions:
- The novel peptide PEP73 exhibits strong inhibitory potential against Hsp90α.
- PEP73 offers a promising therapeutic strategy for breast cancer by destabilizing Hsp90α client proteins.
- This peptide-based approach overcomes limitations associated with traditional Hsp90α inhibitors.
