1. Academic Validation
  2. The small molecule CS1 inhibits mitosis and sister chromatid resolution in HeLa cells

The small molecule CS1 inhibits mitosis and sister chromatid resolution in HeLa cells

  • Biochim Biophys Acta Gen Subj. 2018 May;1862(5):1134-1147. doi: 10.1016/j.bbagen.2018.01.012.
Xingkang Wu 1 Zhenyu Li 2 Yuemao Shen 3
Affiliations

Affiliations

  • 1 Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, No. 44 West Wenhua Road, Jinan, Shandong 250012, PR China.
  • 2 Department of Pharmacy, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, PR China.
  • 3 Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, No. 44 West Wenhua Road, Jinan, Shandong 250012, PR China; State Key Laboratory of Microbial Technology, Shandong University, No. 27 South Shanda Road, Jinan, Shandong 250100, PR China. Electronic address: yshen@sdu.edu.cn.
Abstract

Background: Mitosis, the most dramatic event in the cell cycle, involves the reorganization of virtually all cellular components. Antimitotic agents are useful for dissecting the mechanism of this reorganization. Previously, we found that the small molecule CS1 accumulates cells in G2/M phase [1], but the mechanism of its action remains unknown.

Methods: Cell cycle analysis, live cell imaging and nuclear staining were used. Chromosomal morphology was detected by chromosome spreading. The effects of CS1 on microtubules were confirmed by tubulin polymerization, colchicine tubulin-binding, cellular tubulin polymerization and immunofluorescence assays and by analysis of microtubule dynamics and molecular modeling. Histone phosphoproteomics was performed using mass spectrometry. Cell signaling cascades were analyzed using immunofluorescence, immunoprecipitation, immunoblotting, siRNA knockdown and chemical inhibition of specific proteins.

Results: The small molecule CS1 was shown to be an antimitotic agent. CS1 potently inhibited microtubule polymerization via interaction with the colchicine-binding pocket of tubulin in vitro and inhibited the formation of the spindle apparatus by reducing the bulk of growing microtubules in HeLa cells, which led to activation of the spindle assembly checkpoint (SAC) and mitotic arrest of HeLa cells. Compared with colchicine, CS1 impaired the progression of sister chromatid resolution independent of cohesin dissociation, and this was reversed by the removal of CS1. Additionally, CS1 induced unique histone phosphorylation patterns distinct from those induced by colchicine.

Conclusions and significance: CS1 is a unique antimitotic small molecule and a powerful tool with unprecedented value over colchicine that makes it possible to specifically and conditionally perturb mitotic progression.

Keywords

CS1; Histone phosphorylation; Microtubule inhibitor; Mitotic arrest; Sister chromatid resolution; Spindle assembly checkpoint.

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