Department of Chemistry and Laboratory for Chemical and Biological Sciences, Georgia State University, Atlanta, GA, 30303, Department of Pathology, University of North Carolina, Chapel Hill, North Carolina 27599, INSERM U-524 et Laboratoire de Pharmacologie Antitumorale du Centre Oscar Lambret, IRCL, Place de Verdun, 59045 Lille, France (At 2000-08-31)