title: Significant decrease of ADP release rate underlies the potent activity of dimethylenastron to inhibit mitotic kinesin Eg5 and cancer cell proliferation.
abstract: Eg5 is a mitotic kinesin that plays a crucial role in the formation of bipolar mitotic spindles, by hydrolyzing ATP to push apart anti-parallel microtubules. Dimethylenastron is potent specific small molecule inhibitor of Eg5. The mechanism by which dimethylenastron inhibits Eg5 function remains unclear. By comparing with enastron, here we report that dimethylenastron prevents the growth of pancreatic and lung cancer cells more effectively, by halting mitotic progression and triggering apoptosis. We analyze their interactions with ADP-bound Eg5 crystal structure, and find that dimethylenastron binds Eg5 motor domain with higher affinity. In addition, dimethylenastron allosterically blocks the conformational change of the "sandwich"-like ADP-binding pocket more effectively. We subsequently use biochemical approach to reveal that dimethylenastron slows ADP release more significantly than enastron. These data thus provide biological, structural and mechanistic insights into the potent inhibitory activity of dimethylenastron.
authors.affiliation: Lung Cancer Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heping District, Tianjin 300052, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Songbo
authors.initials: S
authors.lastname: Xie
authors.affiliation: Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
authors.affiliation: Lung Cancer Institute, Tianjin Medical University General Hospital, 154 Anshan Road, Heping District, Tianjin 300052, China; Department of Oncology, Tianjin Medical University General Hospital, 154 Anshan Road, Heping District, Tianjin 300052, China. Electronic address: Zhongdsh@hotmail.com.
authors.forename: Diansheng
authors.initials: D
authors.lastname: Zhong
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D018360:Crystallography, X-Ray; D006801:Humans; D016547:Kinesins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D008938:Mitosis / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D017434:Protein Structure, Tertiary; D011799:Quinazolines / Q000494:pharmacology*; D013871:Thiones / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; C470243:KIF11 protein, human; D011799:Quinazolines; D013871:Thiones; C518969:dimethylenastron; C518968:enastron; D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases; D016547:Kinesins
keywords: ADP release; ATPase activity; Apoptosis; Eg5 inhibitor; Mitotic arrest