[Protective effects of tacrine and donepezil against staurosporine-induced apoptotic death]

Abstract

Aim: To study whether tacrine and donepezil can prevent cell apoptosis induced by staurosporine in NG108-15 and Hela cell lines.

Methods: MTT assay was used to examine if staurosporine impairs cell metabolism. Phase-contrast and fluorescence microscope were used to examine cell morphological changes. DNA was isolated and electrophoretically separated on 1% agarose gel to observe if there were DNA fragments. Western blot was made to analyse protein levels of anti-apoptotic Bcl-2 and proapoptotic Bax.

Results: NG108-15 cells treated with 0.1 mumol.L-1 staurosporine for 12-24 hours exhibited marked cell death and DNA fragmentation. Pre-treatment with 0.1 mmol.L-1 tacrine provided approximately 40% protective effect and resulted in obvious inhibition or delay of DNA fragmentation. Moreover, NG108-15 cells treated with tacrine became elongated and polarized, and showed longer processes than control cells. Pretreatment with 0.1 mmol.L-1 tacrine significantly increased the expression of Bcl-2 protein level and delayed the staurosporine-induced increase of Bax protein expression. However, donepezil did not show any protective effect on the cell impairment induced by staurosporine in NG108-15 cells. In Hela cells 0.1 mumol.L-1 staurosporine also induced significant cell injury, but pretreatment with tacrine and donepezil did not provide any obvious protective effect against this cell damage.

Conclusion: Donepezil did not provide obvious protective effect against apoptosis, and protective effects of tacrine might not be mediated through AChE inhibition. Protective effects of tacrine against staurosporine-induced injury might be selective to different cells.