Abstract 2424: Interferon consensus sequence binding protein promotes epithelial to mesenchymal transition and cell motility in human osteosarcoma cells

Interferon consensus sequence binding protein (ICSBP) is a regulatory factor induced by interferon gamma (IFN-γ) and a member of interferon regulatory family (IRF). ICSBP is mainly expressed in hematopoietic cell and regulates immune response and differentiation but its role in non-hematopoietic cells is largely unknown. Here we investigated a role of ICSBP in human osteosarcoma U2OS cell line. Basal level of ICSBP expression was low but was induced by interferon-γ in U2OS cells. In addition, induced ICSBP promoted U2OS cell proliferation. To further elucidate ICSBP functions in osteosarcoma cells, we generated the U2OS stable cell line that overexpresses ICSBP. ICSBP overexpressing cells grew faster compared with mock cells and showed morphological changes. ICSBP upregulated TGF-βRI expression resulting in activation of TGF-β signaling pathways. In addition, ICSBP expression altered cell morphology and increased cell adhesion and motility. Furthermore ICSBP increased vimentin expression but decreased ZO-1 and E-cadherin expression, which is EMT related phenomena. These motility and EMT related phenomena were inhibited by TGF-βRI inhibitor. Taken together, these findings indicate that ICSBP promotes EMT and cell motility via TGF-β pathways in U2OS cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2424. doi:10.1158/1538-7445.AM2011-2424