1. Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center (UNMC), Omaha, NE, USA
2. National Center for Natural Products Research, University of Mississippi, Mississippi, USA
3. Department of Otolaryngology/Head and Neck Surgery, University of Nebraska Medical Center, Omaha, NE, USA
4. Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
5. Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA