Affiliation: | 1. State Key Laboratory of Bio‐organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, 200032 Shanghai (China), Fax: (+86)?21‐64166128;2. Department of Pharmacology and Department of Oncology, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, 21205 MD (USA) |