Laulimalide and peloruside A inhibit mitosis of Saccharomyces cerevisiae by preventing microtubule depolymerisation-dependent steps in chromosome separation and nuclear positioning.
The activity and mechanism of action of two microtubule-stabilising agents, laulimalide and peloruside A, were investigated in Saccharomyces cerevisiae. In contrast to paclitaxel, both compounds displayed growth inhibitory activity in yeast with wild type TUB2 and were susceptible to the yeast pleiotropic drug efflux pumps, as evidenced by the increased sensitivity of a pump transcription factor knockout strain, pdr1Δpdr3Δ. Laulimalide (IC50=3.7 μM) was 5-fold more potent than peloruside A (IC50=19 μM) in this knockout strain. Bud index assays and flow cytometry revealed a G2/M block as seen in mammalian cells subsequent to treatment with these compounds. Furthermore, peloruside A treatment caused an increase in the number of cells with polymerised spindle microtubules. These results indicate an anti-mitotic action of both compounds with tubulin the likely target. This conclusion was supported by laulimalide and peloruside chemogenomic profiling using a yeast deletion library in the pdr1Δpdr3Δ background. The chemogenomic profiles of these compounds indicate that, in contrast to microtubule destabilising agents like nocodazole and benomyl, laulimalide and peloruside A inhibit mitotic processes that are reliant on microtubule depolymerisation, consistent with their ability to stabilise microtubules. Gene deletion strains hypersensitive to laulimalide and peloruside A represent possible targets for drugs that can synergize with microtubule stabilising agent and be of potential use in combination therapy for the treatment of cancer or other diseases.
Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Kelburn, Wellington, 6011, New Zealand. john.h.miller@vuw.ac.nz.
Heather A
HA
Best
James H
JH
Matthews
Rosemary W
RW
Heathcott
Reem
R
Hanna
Dora C
DC
Leahy
Namal V C
NV
Coorey
David S
DS
Bellows
Paul H
PH
Atkinson
John H
JH
Miller
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D002466:Cell Nucleolus; D020090:Chromosome Segregation / Q000187:drug effects*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D053263:Gene Regulatory Networks; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000494:pharmacology*; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects*; D055503:Protein Multimerization / Q000187:drug effects*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000502:physiology*; D008941:Spindle Apparatus / Q000187:drug effects
D019086:Bridged Bicyclo Compounds, Heterocyclic; D007783:Lactones; D018942:Macrolides; C117305:laulimalide; C414085:peloruside A