P-31 changes as a measure of therapy response in resistant and sensitive osteosarcomas implanted into nude mice

Objective: To determine if changes in PCrPi and PME can be used to predict lack of tumor response to chemotherapy in a murine model of a chemotherapy-resistant human osteosarcoma. Material and Methods: Cisplatin-resistant sublines were grown from high-grade cisplatin-sensitive human osteosarcoma. Surface coil localized 31P NMR spectroscopy of implanted cisplatin-resistant and sensitive osteosarcoma tumors in nude mice was performed. Results: A cisplatin-resistant subline of a sensitive human osteosarcoma was developed that was five times more resistant to cisplatin than the parent cell line. Our NMR data shows a statistically significant difference in the change in the PCrPi ratio after treatment between sensitive and resistant osteosarcomas at the α = 0.05 level. Changes in PME were seen in the sensitive tumors but were not statistically significant. Conclusions: Changes in PCrPi predict lack of tumor treatment response in human osteosarcoma implanted into nude mice with a specificity of 70% and a sensitivity of 54%. Monitoring of PCrPi in human osteosarcoma patients may allow detection of response to chemotherapy before conventional imaging techniques.