Abstract 2434: LEF1 negatively regulates differentiation of HCC by activation of Notch signaling pathway

Abstract

Abstract Lymphoid enhancer binding factor-1 (LEF1), an essential regulatory protein, plays a crucial role on self-renewal and differentiation properties of several cancers, contributing to tumor malignancy degree and prognosis. However, its molecular mechanisms to promote tumor differentiation still keep unknown, especially in hepatocellular carcinoma (HCC). In this study, by analyzing the transcriptome datasets and our qPCR result of clinical HCC samples, we found that LEF is frequently overexpressed in HCCs and significantly associated with HCC differentiation (p=0.015). In addition, functional study showed that LEF1 could enhance the cell proliferation, matrigel invasion, transwell migration, as well as self-renewal abilities both in vivo and in vitro experiments. We also demonstrated LEF1 is closely related to Notch intracellular domain (NICD), and revealed several putative sites as the targets for LEF1 activating Notch signaling pathway. LEF1 could induce the Notch signaling via transcriptionally up-regulate Notch expression through direct DNA binding. The expressions of several downstream members in Notch signaling pathway including Notch1 and Notch2 were subsequently increased. Moreover, LEF1 could down-regulate various differentiation markers and over-express tumor stemness related genes. Together, LEF1 is a novel oncogene that show a crucial role in the tumorigenesis and progression of HCC via activating Notch signaling pathway and inhibiting the differentiation and stemness of HCC, resulting in poor pathologic differentiation and leads to high degree of malignant. All the findings suggest a novel treatment possibility and a new target for liver stem cell eradication. LEF1 could be investigated for clinical early diagnosis and prognosis prediction of HCC patients and improving the development of new therapy against HCC. Note: This abstract was not presented at the meeting. Citation Format: Shuo FANG, Lei LI, MIng LIU, Janice Tsang, Xinyuan GUAN. LEF1 negatively regulates differentiation of HCC by activation of Notch signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2434. doi:10.1158/1538-7445.AM2017-2434