TH588 and Low-Dose Nocodazole Impair Chromosome Congression by Suppressing Microtubule Turnover within the Mitotic Spindle.

Girish Rajendraprasad,Claudia Guasch Boldú,Susana Eibes,Marin Barisic

doi:10.3390/cancers13235995

Girish Rajendraprasad, Claudia Guasch Boldú + Show 2 more

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https://doi.org/10.3390/cancers13235995

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Journal: Cancers	Publication Date: Nov 29, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Danish Cancer Society

Abstract

Simple SummaryA promising anti-cancer compound TH588 has been recently identified as a microtubule-targeting agent that inhibits tubulin polymerization in vitro and interferes with microtubule dynamics in interphase cells. Although it was shown to arrest cells in mitosis, its effect on microtubule dynamics in dividing cells remained unknown. By analyzing microtubule dynamics in living cells treated with either TH588 or low-dose nocodazole, we revealed that both of these drugs stabilize microtubules within the mitotic spindle, leading to premature formation of kinetochore-microtubule end-on attachments on uncongressed chromosomes. This causes mitotic arrest, ultimately resulting in cell death or cell division with uncongressed chromosomes. Both of these cell fates could contribute to the selective effect associated with the activity of TH588 in cancer cells.Microtubule-targeting agents (MTAs) have been used for decades to treat different hematologic and solid cancers. The mode of action of these drugs mainly relies on their ability to bind tubulin subunits and/or microtubules and interfere with microtubule dynamics. In addition to its MTH1-inhibiting activity, TH588 has been recently identified as an MTA, whose anticancer properties were shown to largely depend on its microtubule-targeting ability. Although TH588 inhibited tubulin polymerization in vitro and reduced microtubule plus-end mobility in interphase cells, its effect on microtubule dynamics within the mitotic spindle of dividing cells remained unknown. Here, we performed an in-depth analysis of the impact of TH588 on spindle-associated microtubules and compared it to the effect of low-dose nocodazole. We show that both treatments reduce microtubule turnover within the mitotic spindle. This microtubule-stabilizing effect leads to premature formation of kinetochore-microtubule end-on attachments on uncongressed chromosomes, which consequently cannot be transported to the cell equator, thereby delaying cell division and leading to cell death or division with uncongressed chromosomes.

Highlights

IntroductionMicrotubules (MTs) are filamentous tubular structures, typically consisting of 13 laterally associated protofilaments that are built from α- and β-tubulin heterodimers
We show that the spindle MTs-associated stabilizing effect of TH588 and nocodazole results in a premature formation of kinetochore-MT end-on attachments on uncongressed chromosomes, which leads to severe chromosome congression problems and mitotic arrest
This study demonstrates that the individual actions of two MT-targeting drugs, TH588 and low concentration of nocodazole, reduce MT turnover within the mitotic spindle of dividing cells

Summary

Introduction

Microtubules (MTs) are filamentous tubular structures, typically consisting of 13 laterally associated protofilaments that are built from α- and β-tubulin heterodimers. MTs are highly dynamic, owing to the so-called “dynamic instability” [1,2,3,4,5] that is characterized by constant switching between persistent phases of elongation and shortening. The switch from shortening to elongation is called “rescue” and depends on the formation of a protective “cap” resulting from incorporation of GTP-tubulin into the growing MT end. Within the MT lattice, GTP-tubulin is transformed into GDP-tubulin via hydrolysis. The switch from elongation to shortening is known as “catastrophe” and is characterized by the loss of GTP-tubulin cap that leads to dissociation of GDP-tubulin from the MT [5,6,7]

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