Abstract 1593: GSK3β mediated arsenite induction of spindle abnormalities

Abstract Arsenite induces centrosome amplification and spindle abnormalities, leading to chromosome missegregation and consequently resulting in mitotic cell apoptosis or aneuploidy. However, the underlying mechanism of how arsenite disrupts mitotic spindles is not known. In this study, we showed that CGL2 cells treated with arsenic trioxide (ATO) were arrested at mitotic stage in company with the formation of substantial spindle abnormalities and significant reduction of acetylated- and detyrosinated-tubulin, characteristics of decreased MT stability. Immunofluorescence staining of EB1, a plus-end microtubule-binding protein, revealed discrete EB1 spots distributing along microtubule (MT) nucleated from the two spindle poles in untreated mitotic cells. However, it showed a disorganized pattern in ATO-arrested mitotic cells with the spot-like EB1 clusters splashing all over the cells. In addition, immunoblotting and immunofluorescence staining revealed that the mitosis-specific inhibitory phospho-GSK3 was diminished in ATO-arrested mitotic cells. Pharmacological inhibition of GSK3 could prevent ATO induction of spindle abnormalities, mitotic arrest, and cell death. Since GSK3β has been reported to reduce MT stability by phosphorylating several microtubule-associated proteins, our current results indicated that GSK3β may mediate ATO induction of spindle abnormalities. Citation Format: Tz-Chi Lin, Ren-Meei Chen, Hsiao-Hui Kuo, Ling-Huei Yih. GSK3β mediated arsenite induction of spindle abnormalities. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1593. doi:10.1158/1538-7445.AM2014-1593