1. Department of Pharmaceutical Chemistry & Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
2. Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94158, USA.
3. Department of Chemistry, University of California, Riverside, CA 92521, USA.
4. Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA.
5. Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
6. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02215, USA.