title: Shikonin, a natural product from the root of Lithospermum erythrorhizon, is a cytotoxic DNA-binding agent.
abstract: To search for compounds that disrupt binding of the EWS-FLI1 fusion protein to its cognate targets, we developed a homogeneous high-throughput proximity assay and screened 5200 small molecule compounds. Many well-known DNA-binding chemotherapeutic agents, such as actinomycin D, cisplatin, doxorubicin, daunorubicin, and epirubicin scored in the assay and not surprising also disrupted the binding of other transcription factors. Unexpectedly, we found that Shikonin, a natural product from the root of Lithospermum erythrorhizon, similarly disrupted protein-DNA interactions. Mechanistic studies demonstrated that Shikonin displaces SYBR green from binding to the minor groove of DNA and is able to inhibit topoisomerase mediated DNA relaxation. In cells, Shikonin blocked the binding of EWS-FLI1 to the NR0B1 promoter, and attenuated gene expression. Shikonin rapidly induced G2/M arrest and apoptosis in Ewing sarcoma cells. These results demonstrate that contrary to other purported mechanisms of action, Shikonin is a DNA-binding cytotoxic agent.
authors: Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA.
authors: Changmin
authors: C
authors: Chen
authors: Division of Molecular and Vascular Medicine, Center for Vascular Biology Research, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors: Kumaran
authors: K
authors: Shanmugasundaram
authors: Division of Molecular and Vascular Medicine, Center for Vascular Biology Research, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors: Alan C
authors: AC
authors: Rigby
authors: Division of Pediatric Hematology/Oncology/Stem Cell Transplantation, Columbia University Medical Center, New York, NY 10032, USA. Electronic address: akung@columbia.edu.
authors: Andrew L
authors: AL
authors: Kung
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D053837:DNA Cleavage / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D029684:Lithospermum / Q000737:chemistry*; D009285:Naphthoquinones / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D001688:Biological Products; D009285:Naphthoquinones; C016101:shikonin; D004247:DNA