Paralog Specificity Determines Subcellular Distribution, Action Mechanism, and Anticancer Activity of TRAP1...

Area of Science:

• Molecular Biology
• Cancer Research
• Drug Discovery

Background:

• Heat shock protein 90 (Hsp90) inhibitors show modest anticancer activity due to limited efficacy against cytoplasmic Hsp90.
• Targeting the mitochondrial Hsp90 paralog, TRAP1, with Hsp90 inhibitors can enhance potency.
• Current methods often require mitochondrial delivery vehicles to achieve targeted inhibition.

Purpose of the Study:

• To develop novel Hsp90 inhibitors with improved mitochondrial accumulation without relying on delivery vehicles.
• To design compounds that preferentially bind to and inhibit mitochondrial TRAP1 over cytoplasmic Hsp90.
• To investigate the anticancer efficacy of these novel inhibitors in vitro and in vivo.

Main Methods:

• Structural analysis of Hsp90 inhibitor BIIB021 using X-ray crystallography.
• Modification of the purine ring of BIIB021 to create pyrazolopyrimidine scaffolds.
• In vitro binding assays to assess affinity for TRAP1 versus Hsp90.
• In vivo studies to evaluate TRAP1 inactivation and anticancer activity of the lead compound.

Main Results:

• A novel pyrazolopyrimidine derivative, 12b (DN401), demonstrated enhanced binding affinity for TRAP1 compared to Hsp90.
• Compound 12b effectively inactivated mitochondrial TRAP1 in vivo.
• 12b exhibited potent anticancer activity, suggesting successful targeting of the mitochondrial pathway.

Conclusions:

• Modifying Hsp90 inhibitors to create compounds like 12b offers a strategy to enhance mitochondrial TRAP1 inhibition.
• This approach improves drug accumulation and anticancer efficacy without specialized delivery systems.
• The developed pyrazolopyrimidine scaffold provides a feasible guideline for designing potent TRAP1 inhibitors for cancer therapy.