Suppression of tumor growth in experimental 9L gliosarcoma model by copper depletion

The effect of copper (Cu) depletion on the growth of tumors was investigated in a rat brain tumor model. 9L gliosarcoma cells were injected subcutaneously in 5-week-old male Fischer-344 rats. The control group (n = 18) received a normal diet throughout the experiment and the depletion group (n = 18) received a Cu-deficient diet starting 3 weeks prior to tumor implantation, and 2 mg of D-penicillamine orally, once daily, on the 3 days before and after implantation. Six animals from each group were killed at 1, 2, and 3 weeks following the implantation to measure the tumor weights and determine the tissue Cu concentration by atomic absorption spectrophotometry. The tumor weights increased much more rapidly in the control than in the depletion group. The Cu concentrations in tumor tissue of the depletion group were significantly lower than in the control group. There was no statistical significance in Cu concentration in the brain tissues of the control and depletion groups. Our study indicated that a Cu-deficient diet and D-penicillamine treatment can inhibit subcutaneous glioma growth in this rat model.