1. Division of Medicinal Chemistry, VU University, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands.
2. Department of Molecular, Cellular and Developmental Biology, Natural Science Building, University of Michigan, Ann Arbor, MI 48109, USA.
3. Division of Molecular Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands.