1. ¹Department of Neurosurgery and the Massey Cancer Center, Virginia Commonwealth University Medical Center, PO Box 980631, Richmond, VA 23298-0631, USA
2. ²Departments of Microbiology and Immunology and Pathology, Virginia Commonwealth University Medical Center, PO Box 980631, Richmond, VA 23298-0631, USA

Correspondence: Professor MR Graf, E-mail: mgraf@hsc.vcu.edu

Received 2 April 2007; Revised 21 June 2007; Accepted 26 June 2007; Published online 17 July 2007.

Abstract

The neuro-steroids 3-androstene-17-diol (17-AED), 3-androstene-17-diol (17-AED), 3-androstene-7,-17-triol (7-AET) and 3-androstene-7,-17-triol (7-AET) are metabolites of dehydroepiandrosterone and are produced in neuro-ectodermal tissue. Both epimers of androstenediols (17-AED and 17-AED) and androstenetriols (7-AET and 7-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-AED is the most potent inhibitor, with an IC₅₀ 15 M. For T98G glioma, 90% inhibition was achieved with 25 M of 17-AED. Other neuro-steroids tested only marginally suppressed cell proliferation. Reduced cell adherence and viability could be detected after 18 h of 17-AED exposure. Treatment with 17-AED induced a significant level of apoptosis in U937 lymphoma cells, but not in the glioma cells. Cytopathology of 17-AED-treated T98G cells revealed the presence of multiple cytoplasmic vacuoles. Acridine orange staining demonstrated the formation of acidic vesicular organelles in 17-AED-treated T98G and U251MG, which was inhibited by bafilomycin A1. These findings indicate that 17-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.