Abstract 4130: A novel tumor-suppressor role for squalene epoxidase in human colorectal metastasis

Abstract

Abstract Malignancy cancer cells are reported to develop mechanisms to resist anoikis (apoptotic cell death from deprivation of cell-cell/matrix interactions), thereby enhancing the survival of cancer cells and secondary tumor formation in distant organs, which is responsible for 90% of cancer-related fatalities. A high serum level of cholesterol (hypercholesterolemia) in patients with colorectal cancers (CRCs) metastasis is reported, but the underlying relationship were never elucidated. Human CRC tissues revealed that the expression of squalene epoxidase (SqE), the rate-limiting enzyme in cholesterol synthesis, is significantly reduced in the advanced stages of CRC. Here we report that the knockdown/degradation of SqE by either the application of small-interfering RNA against SqE or a high-level of cholesterol significantly potentiates CRC cell survival/metastasis via the induction of an epithelial-mesenchymal transition as well as of anoikis resistance. We identified the interactions of SqE with glycogen synthase kinase 3β (GSK3β) and/or p53: SqE knockdown induced the dissociation of GSK3β and p53, thereby resulting in the downregulation of E-cadherin via the inhibition of GSK3 activity and of -catenin degradation, as well as the p53 degradation by the hdm2 upregulation. Overall, the present study demonstrates SqE is a key negative regulator of cancer cell survival and of CRC metastasis. Citation Format: Soo Young Jun, Hyun-Soo Cho, Jeong-Ju Lee, Ji-Yong Yoon, Jun-Ho Ahn, Ju-Sik Min, Sujin Jeon, Jae-Hye Lee, Min Hyuk Choi, Nam-Soon Kim. A novel tumor-suppressor role for squalene epoxidase in human colorectal metastasis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4130.