Lymphotoxic activity of methyl prednisolone in vitro—I: Comparative toxicity of methyl prednisolone in human cell lines of B and T origin

Abstract

The cytotoxic activity of methyl prednisolone was compared in EB-3(B), NALM-6(B), CCRF-CEM(T) and RPMI-8226 (plasma cell) cell lines derived from human lymphoid malignancies. Whereas EB-3 cells were steroid-sensitive, NALM-6 cells were partially sensitive and CCRF-CEM and RPMI-8226 were steroid resistant at concentrations of methyl prednisolone up to 10 −4 M. A high concentration of methyl prednisolone, 2.5 × 10 −3 M was toxic to all cell lines. Steroid-sensitivity did not correlate with the incorporation of [ 3H] dexamethasone and could not be mimicked by flurbiprofen, a non-steroidal anti-inflammatory agent. Both theophylline and di-butyryl cAMP were toxic towards NALM-6, EB-3 and CCRF-CEM cells; however, this toxicity was reversible and did not reflect the cells' sensitivities towards methyl prednisolone. Furthermore, elevated levels of cAMP in theophylline-treated cells, were not demonstrable in cells treated with methyl prednisolone at toxic or non-toxic concentrations of the steroid. Steroid-sensitive EB-3 cells exposed to 10 −5 M methyl prednisolone, produced a soluble factor which was toxic CCRF-CEM cells.