1. Laboratory
of Aquatic Natural Products Chemistry, Graduate School of Agricultural
and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
2. Sugashima
Marine Biological Laboratory, Nagoya University, Toba, Mie 517-0004, Japan
3. Takehara
Marine Station, Hiroshima University, Takehara, Hiroshima 725-0024, Japan
4. Molecular
Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States