TCF3 inhibits F9 embryonal carcinoma growth by the down-regulation of Oct4.

T-cell factor 3 (TCF3), a downstream effector of Wnt signaling in embryonic stem (ES) cells, plays an important role in pluripotent self-renewal and proliferation. Loss of TCF3 delays the differentiation of mouse ES cells. The purpose of this study was to investigate the effect of TCF3 on embryonal carcinoma (EC). The mouse F9 EC cell line and a tumor-bearing mouse model were used to evaluate the anti-EC tumor effects of TCF3 in vitro and in vivo, respectively. The overexpression of TCF3 significantly inhibited proliferation, colony-forming and migration in F9 EC cells by approximately 30, 45 and 30%, respectively. The in vivo mouse model showed that the overexpression of TCF3 significantly reduced tumor volume (36.4%) and tumor weight (34.8%), malignancy progression and local infiltration and prolonged the life span of tumor-bearing mice. Overexpression of TCF3 significantly down-regulated Oct4 expression in the F9 EC cells. The results indicate that TCF3 is an inhibitor of the malignant phenotypes of embryonal carcinoma through the regulation of Oct4 expression.