The epithelial-mesenchymal transition (EMT) program is often activated in cancer cells during invasion and metastasis. During EMT, expression of transcription factors such as Snail and Slug is induced due to the reduction in E-cadherin expression. In addition, matrix metallo-proteinases (MMPs) which digest the various components of extracellular matrix also induced during EMT. Various signaling pathways have been involved in the regulation of EMT program. We hypothesize that notch signaling pathway is a potential regulator of EMT program in HCC.
Lysates from human HCC cell lines, Huh-7, HepG2, and Hep3B, were analyzed for the expression of active notch intracellular domain (NICD) 1-3 proteins by western analysis. To determine the role of NICD3 in cancer invasion and metastasis, siRNA against NICD3 was transfected into HCC cell lines. The effect of depletion of NICD3 in HCC cell lines, epithelial-mesenchymal transition (EMT) markers were measured by western analyses.
Results: Varied level of expression of NICD1-3 was observed in HCC cell lines tested. Transfection of siRNA against NICD3 reduced the level of NICD3 but not the NICD1 protein. Western analysis for the EMT markers expression showed an increase in E-cadherin and concomitant reduction in Snail, Slug, Matrix Metallo Proteinases (MMPs) 2 and 9.
NICD3 inhibition significantly reduced the expression of markers of metastasis by increasing E-cadherin and suppressing transcription factors Snail, Slug, and MMPs. These observed change in the protein levels are occurred in the absence of NICD3 protein but the presence of NICD1 protein suggesting that NICD3 may play a role in metastasis. Therefore, targeting NICD3 may be potential strategy for treatment of HCC.
Citation Format: Selvi Kunnimalaiyaan, T. Clark Gamblin, Muthusamy Kunnimalaiyaan. Role of notch3 in epithelial-to-mesenchymal transition of HCC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5289. doi:10.1158/1538-7445.AM2014-5289