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Updated: Aug 7, 2026
Malachite Green Assay for the Discovery of Heat-Shock Protein 90 Inhibitors
Published on: January 20, 2023
Inhibition of neuroblastoma xenograft growth by Hsp90 inhibitors
Junghee Kang1, Adeela Kamal, Francis J Burrows
1Department of Surgery, The University of Texas Medical Branch, Galveston, TX 7755, USA.
Background:
Advanced-stage neuroblastomas are often resistant to chemotherapy. Heat shock protein (Hsp) 90 is a molecular chaperone that maintains the stability of important signal transduction proteins. We have previously reported that geldanamycin (GA), an Hsp90 inhibitor, decreases Raf-1 and Akt protein expressions and induces apoptosis in neuroblastoma cells. We sought to determine the in vivo effects of Hsp90 inhibitor compounds on human neuroblastomas.
Materials And Methods:
Human neuroblastoma (LAN-1 and SK-N-SH) xenografts (4-mm3 tumor implants) were placed in the flanks of athymic nude mice. The mice received either Hsp90 inhibitors (17-AAG or EC5) or vehicle (control). The tumor dimensions were measured twice weekly. Proteins were extracted for Western immunoblotting.
Results:
Hsp90 inhibitor compounds significantly blocked both LAN-1 and SK-N-SH neuroblastoma growth in vivo. Drug-treated tumors showed decreases in Raf-1 and cleaved PARP expressions.
Conclusion:
Hsp90 inhibitors may prove to be important novel therapeutic agents for patients with advanced-stage neuroblastoma who fail to respond to current treatment regimens.
Insights
Heat shock protein (Hsp) 90 inhibitors effectively reduced neuroblastoma tumor growth in vivo. These compounds represent a promising new treatment for advanced neuroblastoma resistant to conventional therapies.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Advanced-stage neuroblastomas exhibit resistance to chemotherapy.
- Heat shock protein (Hsp) 90 is crucial for maintaining signal transduction proteins.
- Previous studies showed Hsp90 inhibition induces apoptosis in neuroblastoma cells.
Purpose of the Study:
- To evaluate the in vivo efficacy of Hsp90 inhibitor compounds against human neuroblastomas.
- To assess the impact of Hsp90 inhibitors on tumor growth and protein expression in a preclinical model.
Main Methods:
- Human neuroblastoma xenografts (LAN-1 and SK-N-SH) were established in athymic nude mice.
- Mice received Hsp90 inhibitors (17-AAG or EC5) or a vehicle control.
- Tumor dimensions were monitored, and protein levels (Raf-1, cleaved PARP) were analyzed via Western immunoblotting.
Main Results:
- Hsp90 inhibitor treatment significantly inhibited the growth of both LAN-1 and SK-N-SH neuroblastoma xenografts.
- Drug-treated tumors demonstrated reduced expression of Raf-1 and cleaved PARP proteins.
- Hsp90 inhibition effectively suppressed tumor progression in vivo.
Conclusions:
- Hsp90 inhibitors show potential as novel therapeutic agents for advanced neuroblastoma.
- These findings suggest a promising treatment strategy for patients unresponsive to current therapies.
- Targeting Hsp90 offers a new avenue for neuroblastoma treatment.
