31P changes as a measure of therapy response in human osteosarcomas implanted into nude mice

Phosphomonoester concentrations differ between chronic lymphocytic leukemia cells and normal human lymphocytes

Levels of phospholipid-related metabolites of chronic lymphocytic leukemia lymphocytes (CLL) and normal human lymphocytes were quantified using phosphorus magnetic resonance spectroscopy. The CLL cells versus normal lymphocytes showed significant increases of phosphoethanolamine(Etn-P) (8.11+/-2.10 mean+/-S.E., micromol/g wet weight, n=12 versus 3.63+/-1.10, n=3, P<or=0.002), phosphocholine (2.10+/-0.37, n=12 versus 0.36+/-0.09, n=3, P<or=0.01), glycerophosphoethanolamine (0.26+/-0.03, n=10 versus 0.11+/-0.05, n=3, P<or=0.004), and glycerophosphocholine (0.33+/-0.03, n=10 versus 0.17+/-0.05, n=3, P<or=0.003). Further, the phospholipid precursor ethanolamine (Eth) was studied in blood and was found significantly lowered in CLL patients (4.6+/-1.6 microM, n=25) compared to normal volunteers (7.7+/-2.5, n=12, P<or=0.001). Increased intermediates with depletion of precursors suggest the presence of sustained phospholipid metabolism activation in CLL.

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

OBJECTIVE

To determine if changes in PCr/Pi 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 PCr/Pi ratio after treatment between sensitive and resistant osteosarcomas at the alpha = 0.05 level. Changes in PME were seen in the sensitive tumors but were not statistically significant.

CONCLUSIONS

Changes in PCr/Pi 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 PCr/Pi in human osteosarcoma patients may allow detection of response to chemotherapy before conventional imaging techniques.