3,5-bis(styryl)pyrazole inhibits mitosis and induces cell death independent of BubR1 and p53 levels by depolymerizing microtubules

Abstract

Here, we show that 3,5-bis[(1E)-2-(2,6-dichlorophenyl)ethenyl]-1H-pyrazole 2l depolymerizes microtubules and reduces the number of growing tips of microtubules. The fluorescence recovery after photobleaching experiment in live MCF-7 cells showed that pyrazole 2l suppresses spindle microtubule dynamics. Further, the compound inhibits chromosome movements, activates the spindle assembly checkpoint and blocks mitosis in MCF-7 cells. Pyrazole 2l treatment induced cell death in a variety of pathways. Pyrazole 2l induces cell death independent of BubR1 and p53 levels of MCF-7 cells upon microtubule depolymerization. Further, pyrazole 2l increases the interaction between NF-κB and microtubules and enhances the nuclear localization of NF-κB at its half-maximal proliferation inhibitory concentration while a high concentration of the compound reduced the nuclear localization of NF-κB. Interestingly, the compound exerted significantly stronger antiproliferative effects in cancerous cells than in non-cancerous cells. The results indicated that pyrazole 2l inhibits mitosis by targeting microtubules, induces several types of cell death stimuli and suggests its potential as a lead in developing anticancer agent.

Keywords: Abbreviations: BSA, bovine serum albumin; CI, congression index; FBS, fetal bovine serum; FRAP, fluorescence recovery after photobleaching; pHH3, phospho-Histone H3 (Ser10); PI, propidium iodide; SAC, spindle assembly checkpoint; cell death; chromosome dynamics; congression index; microtubule dynamics; mitotic index.