title: Peloruside- and laulimalide-resistant human ovarian carcinoma cells have βI-tubulin mutations and altered expression of βII- and βIII-tubulin isotypes.
abstract: Peloruside A and laulimalide are potent microtubule-stabilizing natural products with a mechanism of action similar to that of paclitaxel. However, the binding site of peloruside A and laulimalide on tubulin remains poorly understood. Drug resistance in anticancer treatment is a serious problem. We developed peloruside A- and laulimalide-resistant cell lines by selecting 1A9 human ovarian carcinoma cells that were able to grow in the presence of one of these agents. The 1A9-laulimalide resistant cells (L4) were 39-fold resistant to the selecting agent and 39-fold cross-resistant to peloruside A, whereas the 1A9-peloruside A resistant cells (R1) were 6-fold resistant to the selecting agent while they remained sensitive to laulimalide. Neither cell line showed resistance to paclitaxel or other drugs that bind to the taxoid site on β-tubulin nor was there resistance to microtubule-destabilizing drugs. The resistant cells exhibited impaired peloruside A/laulimalide-induced tubulin polymerization and impaired mitotic arrest. Tubulin mutations were found in the βI-tubulin isotype, R306H or R306C for L4 and A296T for R1 cells. This is the first cell-based evidence to support a β-tubulin-binding site for peloruside A and laulimalide. To determine whether the different resistance phenotypes of the cells were attributable to any other tubulin alterations, the β-tubulin isotype composition of the cells was examined. Increased expression of βII- and βIII-tubulin was observed in L4 cells only. These results provide insight into how alterations in tubulin lead to unique resistance profiles for two drugs, peloruside A and laulimalide, that have a similar mode of action.
authors.affiliation: School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
authors.forename: Arun
authors.initials: A
authors.lastname: Kanakkanthara
authors.forename: Anja
authors.initials: A
authors.lastname: Wilmes
authors.forename: Aurora
authors.initials: A
authors.lastname: O'Brate
authors.forename: Daniel
authors.initials: D
authors.lastname: Escuin
authors.forename: Ariane
authors.initials: A
authors.lastname: Chan
authors.forename: Ada
authors.initials: A
authors.lastname: Gjyrezi
authors.forename: Janet
authors.initials: J
authors.lastname: Crawford
authors.forename: Pisana
authors.initials: P
authors.lastname: Rawson
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Kivell
authors.forename: Peter T
authors.initials: PT
authors.lastname: Northcote
authors.forename: Ernest
authors.initials: E
authors.lastname: Hamel
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Giannakakou
authors.forename: John H
authors.initials: JH
authors.lastname: Miller
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D007783:Lactones / Q000378:metabolism / Q000494:pharmacology*; D018942:Macrolides / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D055503:Protein Multimerization / Q000187:drug effects; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007783:Lactones; D018942:Macrolides; D014404:Tubulin; C117305:laulimalide; C414085:peloruside A