Vitamin E Increases the Growth Inhibitory and Differentiating Effects of Tumor Therapeutic Agents on Neuroblastoma and Glioma Cells in Culture 1

Summary

The effects of vitamin E in combination with several pharmacological agents on neuroblastoma (NBP₂) and glioma (C-6) cells in culture for the criteria of growth inhibition (due to cell death and reduction of cell division) and morphological changes were studied. Vitamin E in combination with 5-FU, adriamycin, R020-1724, vincristine, sodium butyrate, chlorozotocin, or PGE₁ produced a synergistic effect on growth inhibition of NB cells, whereas, vitamin E in combination with bleomycin, CCNU, DTIC, mutamycin, or cis-platinum produced an additive effect for the same criterion. In glioma cell culture, vitamin E in combination with vincristine, R020-1724, and CCNU produced a synergistic effect on growth inhibition; whereas, vitamin E in combination with bleomycin, 5-FU, adriamycin, DTIC, papaverine, mutamycin, and cis-platinum produced an additive effect for the same criterion. Vitamin E failed to enhance the effect of sodium butyrate, PGE₁, chlorozotocin on glioma cells. Bleomycin, CCNU, chlorozotocin, or vitamin E at concentrations used in this study did not increase the morphological differentiation of NB cells, however, vitamin E in combination with one of these agents markedly enhanced the number of morphologically differentiated NB cells. Adriamycin, PGE₁, R020-1724, papaverine, mutamycin, and cis-platinum increased the expression of morphological differentiation of NB cells, but vitamin E enhanced the effect of these agents for this criterion. The treatment of glioma cells with vitamin E and pharmacological agents did not cause any significant change in morphological differentiation. These data also suggest that vitamin E may modulate the effects of pharmacological agents.