The neuro-steroid, 3β androstene 17α diol exhibits potent cytotoxic effects on human malignant glioma and lymphoma cells through different programmed cell death pathways

The neuro-steroids 3 beta-androstene-17 alpha-diol (17 alpha-AED), 3 beta-androstene-17 beta-diol (17 beta-AED), 3 beta-androstene-7 alpha,-17 beta-triol (7 alpha-AET) and 3 beta-androstene-7 beta,-17 beta-triol (7 beta-AET) are metabolites of dehydroepiandrosterone and are produced in neuro-ectodermal tissue. Both epimers of androstenediols (17 alpha-AED and 17 beta-AED) and androstenetriols (7 alpha-AET and 7 beta-AET) have markedly different biological functions of their chemical analogue. We investigated the cytotoxic activity of these neuro-steroids on human T98G and U251MG glioblastoma and U937 lymphoma cells. Proliferation studies showed that 17 alpha-AED is the most potent inhibitor, with an IC50 similar to 15 mu M. For T98G glioma, 90% inhibition was achieved with 25 mu M of 17 alpha-AED. Other neuro-steroids tested only marginally suppressed cell proliferation. Reduced cell adherence and viability could be detected after 18 h of 17 alpha-AED exposure. Treatment with 17 alpha-AED induced a significant level of apoptosis in U937 lymphoma cells, but not in the glioma cells. Cytopathology of 17 alpha-AED-treated T98G cells revealed the presence of multiple cytoplasmic vacuoles. Acridine orange staining demonstrated the formation of acidic vesicular organelles in 17 alpha-AED-treated T98G and U251MG, which was inhibited by bafilomycin A1. These findings indicate that 17 alpha-AED bears the most potent cytotoxic activity of the neuro-steroids tested, and the effectiveness may depend on the number of hydroxyls and their position on the androstene molecule. These cytotoxic effects may utilize a non-apoptotic pathway in malignant glioma cells.