1. Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore
2. Cancer Science Institute of Singapore, Yong Loo Lin School of Medicine, National University of Singapore, 117599 Singapore
3. Division of Oral Biology and Medicine, Division of Advanced Prosthodontics, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, California NanoSystems Institute, and Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, California 90095, United States