title: An antitubulin agent BCFMT inhibits proliferation of cancer cells and induces cell death by inhibiting microtubule dynamics.
abstract: Using cell based screening assay, we identified a novel anti-tubulin agent (Z)-5-((5-(4-bromo-3-chlorophenyl)furan-2-yl)methylene)-2-thioxothiazolidin-4-one (BCFMT) that inhibited proliferation of human cervical carcinoma (HeLa) (IC(50), 7.2 ± 1.8 µM), human breast adenocarcinoma (MCF-7) (IC(50), 10.0 ± 0.5 µM), highly metastatic breast adenocarcinoma (MDA-MB-231) (IC(50), 6.0 ± 1 µM), cisplatin-resistant human ovarian carcinoma (A2780-cis) (IC(50), 5.8 ± 0.3 µM) and multi-drug resistant mouse mammary tumor (EMT6/AR1) (IC(50), 6.5 ± 1 µM) cells. Using several complimentary strategies, BCFMT was found to inhibit cancer cell proliferation at G2/M phase of the cell cycle apparently by targeting microtubules. In addition, BCFMT strongly suppressed the dynamics of individual microtubules in live MCF-7 cells. At its half maximal proliferation inhibitory concentration (10 µM), BCFMT reduced the rates of growing and shortening phases of microtubules in MCF-7 cells by 37 and 40%, respectively. Further, it increased the time microtubules spent in the pause (neither growing nor shortening detectably) state by 135% and reduced the dynamicity (dimer exchange per unit time) of microtubules by 70%. In vitro, BCFMT bound to tubulin with a dissociation constant of 8.3 ± 1.8 µM, inhibited tubulin assembly and suppressed GTPase activity of microtubules. BCFMT competitively inhibited the binding of BODIPY FL-vinblastine to tubulin with an inhibitory concentration (K(i)) of 5.2 ± 1.5 µM suggesting that it binds to tubulin at the vinblastine site. In cultured cells, BCFMT-treatment depolymerized interphase microtubules, perturbed the spindle organization and accumulated checkpoint proteins (BubR1 and Mad2) at the kinetochores. BCFMT-treated MCF-7 cells showed enhanced nuclear accumulation of p53 and its downstream p21, which consequently activated apoptosis in these cells. The results suggested that BCFMT inhibits proliferation of several types of cancer cells including drug resistance cells by suppressing microtubule dynamics and indicated that the compound may have chemotherapeutic potential.
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.
authors.forename: Ankit
authors.initials: A
authors.lastname: Rai
authors.forename: Avadhesha
authors.initials: A
authors.lastname: Surolia
authors.forename: Dulal
authors.initials: D
authors.lastname: Panda
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D056744:Cyclin B1 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D018386:Kinetochores / Q000187:drug effects; D064246:Mad2 Proteins; D051379:Mice; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism*; D008940:Mitotic Index; D009369:Neoplasms / Q000473:pathology*; D058105:Polymerization / Q000187:drug effects; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012236:Rhodanine / Q000494:pharmacology; D053778:Thiazolidines / Q000737:chemistry / Q000494:pharmacology*; D013871:Thiones / Q000737:chemistry / Q000494:pharmacology*; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators / Q000737:chemistry / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014747:Vinblastine / Q000494:pharmacology
chemical_list: C538930:3-anilino difluoroboron dipyrromethene; C578067:5-((5-(4-bromo-3-chlorophenyl)furan-2-yl)methylene)-2-thioxothiazolidin-4-one; C584278:Bub1b protein, mouse; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D012097:Repressor Proteins; D053778:Thiazolidines; D013871:Thiones; D014404:Tubulin; D050257:Tubulin Modulators; D016159:Tumor Suppressor Protein p53; D014747:Vinblastine; D011162:Porphobilinogen; D012236:Rhodanine; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases