Lidamycin is a potential anti-cancer drug, which is widely used in a variety of human cancer types. It has been reported that lidamycin inhibited mouse embryonic carcinoma (EC) cells growth through down-regulation of embryonic stem (ES) cell-like genes. In this study, whether 0.01 nM lidamycin induces neuronal differentiation of mouse EC cells was investigated. It was observed that lidamycin decreased transcription factor Oct4, and increased both p21 mRNA and protein expression in P19 EC cells. Furthermore, luciferase assay showed that lidamycin activated p21 promoter activity through suppression of Oct4, and Chromatin immunoprecipitation (ChIP) assay confirmed that binding of transcription factor Oct4 to the p21 promoter decreased in lidamycin-exposed cells. Knockdown of Oct4 resulted in neuron-like differentiation and up-regulation of p21 expression. In accordance, overexpression of Oct4 blocked neural differentiation and down-regulated p21 in lidamycin-treated P19 cells. Taken together, these results suggested that neuronal differentiation of EC cells induced by lidamycin was associated with the inhibition of Oct4 expression and the activation of p21 transcription. Our results have provided a novel mechanism, in which lidamycin led to cancer cell differentiation. (C) 2012 Elsevier Inc. All rights reserved.