ABSTRACT
During early vertebrate embryogenesis, the expression of SOXB1 proteins is precisely regulated by a number of different mechanisms, including Wnt/ß-catenin signaling. This is essential for controlling the balance between stemness and differentiation in embryonic stem cells. In the present study, we analyzed the molecular mechanism of LiCl action in NT2/D1 cells and examined the crosstalk between SOXB1 proteins and Wnt signaling in this model system. We have shown that LiCl increases ß-catenin level, induces its translocation to the nucleus and consequently up-regulates ß-catenin/Tcf-dependent transcription in NT2/D1 cells. Our results also suggest that LiCl treatment leads to increased expression of SOX2 and SOX3 proteins in NT2/D1 cells through activation of canonical Wnt signaling. Finally, we have detected a negative feedback loop between ß-catenin and SOX2 expression in NT2/D1 cells. Since ß-catenin and SOX2 have been linked to processes of self-renewal and pluripotency, our results have implications for future research on the maintenance of stemness and lineage commitment of embryonic stem cells.
Subject(s)
SOXB1 Transcription Factors/metabolism , Wnt Proteins/metabolism , Wnt Signaling Pathway , beta Catenin/metabolism , Humans , Lithium Chloride/chemistry , Tumor Cells, CulturedABSTRACT
The altered expression of the SOX2 transcription factor is associated with oncogenic or tumor suppressor functions in human cancers. This factor regulates the migration and invasion of different cancer cells. In this study we investigated the effect of constitutive SOX2 overexpression on the migration and adhesion capacity of embryonal teratocarcinoma NT2/D1 cells derived from a metastasis of a human testicular germ cell tumor. We detected that increased SOX2 expression changed the speed, mode and path of cell migration, but not the adhesion ability of NT2/D1 cells. Additionally, we demonstrated that SOX2 overexpression increased the expression of the tumor suppressor protein p53 and the HDM2 oncogene. Our results contribute to the better understanding of the effect of SOX2 on the behavior of tumor cells originating from a human testicular germ cell tumor. Considering that NT2/D1 cells resemble cancer stem cells in many features, our results could contribute to the elucidation of the role of SOX2 in cancer stem cells behavior and the process of metastasis.
Subject(s)
Cell Movement/physiology , SOXB1 Transcription Factors/metabolism , Teratocarcinoma/metabolism , Cell Adhesion/physiology , Cell Line, Tumor , Cell Proliferation , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , Male , Teratocarcinoma/pathology , Tissue Array AnalysisABSTRACT
Quercetin, a bioflavonoid found in plant foods, has a wide range of therapeutic effects. In order to examine the therapeutic potential of quercetin in teratocarcinoma, we used the human teratocarcinoma cell line NT2/D1 as an in vitro model. We have shown that quercetin inhibits the proliferation, adhesion and migration of NT2/D1 cells and downregulates the expression of pluripotency factors SOX2, Oct4 and Nanog. Our results further suggest that the anticancer effect of quercetin against human teratocarcinoma cells is mediated by targeting the canonical Wnt signaling pathway. Quercetin antagonized the Wnt/ß-catenin signaling pathway in NT2/D1 cells by inhibiting ß-catenin nuclear translocation and the consequent downregulation of ß-catenin-dependent transcription. These data suggest that quercetin as a potent inhibitor of Wnt signaling may be an effective therapeutic agent in cancers with aberrant activation of the Wnt pathway.