title: The acetylenic tricyclic bis(cyano enone), TBE-31, targets microtubule dynamics and cell polarity in migrating cells.
abstract: Cell migration is dependent on the microtubule network for structural support as well as for the proper delivery and positioning of polarity proteins at the leading edge of migrating cells. Identification of drugs that target cytoskeletal-dependent cell migration and protein transport in polarized migrating cells is important in understanding the cell biology of normal and tumor cells and can lead to new therapeutic targets in disease processes. Here, we show that the tricyclic compound TBE-31 directly binds to tubulin and interferes with microtubule dynamics, as assessed by end binding 1 (EB1) live cell imaging. Interestingly, this interference is independent of in vitro tubulin polymerization. Using immunofluorescence microscopy, we also observed that TBE-31 interferes with the polarity of migratory cells. The polarity proteins Rac1, IQGAP and Tiam1 were localized at the leading edge of DMSO-treated migrating cell, but were observed to be in multiple protrusions around the cell periphery of TBE-31-treated cells. Finally, we observed that TBE-31 inhibits the migration of Rat2 fibroblasts with an IC50 of 0.75 μM. Taken together, our results suggest that the inhibition of cell migration by TBE-31 may result from the improper maintenance of cell polarity of migrating cells.
authors.affiliation: Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
authors.forename: Eddie
authors.initials: E
authors.lastname: Chan
authors.affiliation: Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.affiliation: Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, USA; Department of Chemistry, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Honda
authors.affiliation: Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada. Electronic address: john.diguglielmo@schulich.uwo.ca.
authors.forename: Gianni M
authors.initials: GM
authors.lastname: Di Guglielmo
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D016764:Cell Polarity / Q000187:drug effects*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism; D008907:Mink; D010616:Phenanthrenes / Q000494:pharmacology*; D051381:Rats; D014404:Tubulin / Q000378:metabolism
chemical_list: D010616:Phenanthrenes; C531972:TBE 31; D014404:Tubulin
keywords: Cytoskeleton; Immunofluorescence microscopy; Live cell imaging; Rac1