Quercetin protects neuroblastoma SH-SY5Y cells against oxidative stress by inhibiting expression of Krüppel-like factor 4.

Quercetin is one of flavonoids with cyto-protective activities. It has been demonstrated that quercetin inhibits oxidative stress in some animal models and specific cells, but the particular mechanism is known a little. In the present study, we found that quercetin could decrease the expression of Krüppel-like factor 4 (KLF4) induced by hydrogen peroxide (H(2)O(2)) in human neuroblastoma SH-SY5Y cells, further increase the expression ratio of bcl-2 to bax, which were apoptotic-related target genes of KLF4, thus alleviate the apoptotic rate and caspase-3 enzyme activity of SH-5YSY cells; the overexpression or inhibition of KLF4 demonstrated the mediated role of KLF4 for the protective effect of quercetin on cell damage induced by H(2)O(2). All results suggest a potential molecular mechanism of quercetin protecting against the oxidative damage, which may be applied in the treatment of oxidative related diseases, such as neurodegeneration diseases.