title: MT119, a new planar-structured compound, targets the colchicine site of tubulin arresting mitosis and inhibiting tumor cell proliferation.
abstract: Microtubule-targeted drugs are now indispensable for the therapy of various cancer types worldwide. In this article, we report MT119 [6-[2-(4-methoxyphenyl) -ethyl]-9-[(pyridine-3-ylmethyl)amino]pyrido[2',1':2,3]imida-zo[4,5-c]isoquinolin-5(6H)-one] as a new microtubule-targeted agent. MT119 inhibited tubulin polymerization significantly both in tumor cells and in cell-free systems, which was followed by the disruption of mitotic spindle assembly. Surface plasmon resonance-based analyses showed that MT119 bound to purified tubulin directly, with the K(D) value of 10.6 μM. The binding of MT119 in turn caused tubulin conformational changes as evidenced by the quenched tryptophan fluorescence, the reduction of the bis-ANS reactivity and the decreased DTNB-sulfhydryl reaction rate. Competitive binding assays further revealed that MT119 bound to tubulin at its colchicine site. Consequently, by inhibiting tubulin polymerization, MT119 arrested different tumor cells at mitotic phase, which contributed to its potent antitumor activity in vitro. MT119 was also similarly cytotoxic to vincristine-, adriamycin- or mitoxantrone-resistant cancer cells and to their corresponding parental cells. Together, these data indicate that MT119 represents a new class of colchicine-site-targeted inhibitors against tubulin polymerization, which might be a promising starting point for future cancer therapeutics.
authors.affiliation: Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Meng
authors.forename: Na
authors.initials: N
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Xiong
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Lanping
authors.initials: L
authors.lastname: Ma
authors.forename: Jingkang
authors.initials: J
authors.lastname: Shen
authors.forename: Ze-Hong
authors.initials: ZH
authors.lastname: Miao
authors.forename: Jian
authors.initials: J
authors.lastname: Ding
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003078:Colchicine / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008938:Mitosis / Q000187:drug effects*; D015394:Molecular Structure; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D014404:Tubulin / Q000737:chemistry / Q000187:drug effects*
chemical_list: C559146:6-(2-(4-methoxyphenyl)ethyl)-9-((pyridine-3-ylmethyl)amino)pyrido(2',1'-2,3)imidazo(4,5-c)isoquinolin-5(6H)-one; D000970:Antineoplastic Agents; D006576:Heterocyclic Compounds, 4 or More Rings; D014404:Tubulin; D003078:Colchicine