Effects of glucose on neuroblastoma in vitro and in vivo

Because neuroblastoma cells in vitro are sensitive to changes in glucose levels in growth media, the effects of glucose levels and dietary carbohydrate on the sensitivity of neuroblastoma cells to chemotherapy were studied. In vitro, 20 microM bromoacetylcholine, 3mM 1,3-diaminopropane, and 5 mM 5-fluorouracil were added to the growth medium of strain N2a neuroblastoma cells cultured in Dulbecco's modified Eagle medium with high glucose (4.5 g/L, HG), normal glucose (1.0 g/L, NG), or low glucose (0.1 g/L, LG). Diaminopropane and 5-fluorouracil had some cytotoxic effect on cells in all media. Bromoacetylcholine killed cells in all media, but at a concentration of 20 microM was most effective in LG medium. Mice (A/Jax) were inoculated with neuroblastoma cells for in vivo studies. Mice could not tolerate a carbohydrate-free diet, while a high-carbohydrate diet caused no change in survival time. When mice on a high carbohydrate diet were treated with cyclophosphamide (100 mg/kg, ip) or 5-fluorouracil (125 mg/kg, ip) they died faster than drug-treated mice on a normal diet. Oral chlorpropamide or cimetidine did not prolong survival time. Analysis of blood glucose levels showed neuroblastoma significantly lowered blood glucose levels (p less than 0.05), while chlorpropamide had no significant effect. It is proposed that manipulation of plasma glucose to lower levels will not be effective in enhancing the chemotherapy of neuroblastoma.