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Updated: Jun 22, 2026
Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro
Published on: March 18, 2014
The novel HSP90 inhibitor STA-1474 exhibits biologic activity against osteosarcoma cell lines
Jennifer K McCleese1, Misty D Bear, Stacey L Fossey
1Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Abstract:
Osteosarcoma (OSA), the most common malignant bone tumor in dogs and children, exhibits a similar clinical presentation and molecular biology in both species. Unfortunately, 30-40% of children and 90% of dogs still die of disease despite aggressive therapy. The purpose of this study was to test the biologic activity of a novel heat shock protein 90 (HSP90) inhibitor, STA-1474, against OSA. Canine and human OSA cell lines and normal canine osteoblasts were treated with STA-1474 and evaluated for effects on proliferation (CyQuant), apoptosis (Annexin V, PARP cleavage, caspase 3/7 activation) and known HSP90 client proteins. HSP90 was immunoprecipitated from normal and malignant osteoblasts and Western blotting for co-chaperones was performed. Mice bearing canine OSA xenografts were treated with STA-1474, and tumors samples were evaluated for caspase-3 activation and loss of p-Akt/Akt. Treatment with STA-1474 promoted loss of cell viability, inhibition of cell proliferation and induction of apoptosis in OSA cell lines. STA-1474 and its active metabolite STA-9090 also demonstrated increased potency compared to 17-AAG. STA-1474 exhibited selectivity for OSA cells versus normal canine osteoblasts, and HSP90 co-precipitated with co-chaperones p23 and Hop in canine OSA cells but not in normal canine osteoblasts. Furthermore, STA-1474 downregulated the expression of p-Met/Met, p-Akt/Akt and p-STAT3. Finally, STA-1474 induced tumor regression, caspase-3 activation and downregulation of p-Met/Met and p-Akt/Akt in OSA xenografts. Together, these data suggest that HSP90 represents a relevant target for therapeutic intervention in OSA.
Insights
A novel heat shock protein 90 (HSP90) inhibitor, STA-1474, effectively reduced osteosarcoma (OSA) cell viability and induced apoptosis in preclinical models. This suggests HSP90 is a promising therapeutic target for canine and human OSA.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Osteosarcoma (OSA) is a common bone cancer in dogs and children with poor outcomes.
- Current therapies are insufficient, with high mortality rates in both species.
- Heat shock protein 90 (HSP90) is implicated in cancer cell survival and proliferation.
Purpose of the Study:
- To evaluate the anti-cancer activity of a novel HSP90 inhibitor, STA-1474, against osteosarcoma.
- To assess the drug's effects on OSA cell viability, proliferation, and apoptosis.
- To investigate HSP90's role as a therapeutic target in OSA.
Main Methods:
- In vitro treatment of canine and human OSA cell lines and normal canine osteoblasts with STA-1474.
- Assessment of cell viability, proliferation, apoptosis markers, and HSP90 client proteins.
- In vivo studies using canine OSA xenografts in mice treated with STA-1474.
Main Results:
- STA-1474 significantly reduced OSA cell viability, inhibited proliferation, and induced apoptosis.
- The drug showed greater potency than 17-AAG and selectivity for OSA cells over normal cells.
- STA-1474 treatment in vivo led to tumor regression and modulation of key signaling pathways.
Conclusions:
- HSP90 inhibition with STA-1474 demonstrates significant anti-tumor activity in preclinical osteosarcoma models.
- STA-1474 effectively targets OSA cells, suggesting its potential as a novel therapeutic agent.
- These findings highlight HSP90 as a viable therapeutic target for osteosarcoma treatment.
