25-hydroxycholesterol Regulates Migration, Invasion and EMT of Colorectal Cancer through miR-92a-3p/ACAA1/NF-κB Pathway

Abstract

Background: Colorectal cancer (CRC) is one of the most common malignances worldwide. Several studies suggest a positive association between high plasma cholesterol level and CRC. 25-hydroxycholesterol (25-HC) is enzymatically produced by cholesterol 25-hydorxylase in various organs and is involved in many processes. However, the critical role of 25-HC in the tumor growth and progression of CRC is largely unknown. Methods: CCK-8 assay, flow cytometry and Transwell migration and invasion assays were used to determine the effects of 25-HC on CRC cells proliferation, apoptosis and metastasis. Subcutaneous xenograft model and intra-splenic injection mouse model were established to investigate the effects of 25-HC on CRC in vivo. Immunohistochemistry staining was performed to determine the matrix metalloproteinases (MMPs) expressions in mice tumors and acetyl-CoA acyltransferase 1 (ACAA1) expression in human CRC tissues. The expressions of E-cadherin, N-cadherin and Vimentin were examined by immunofluorescent staining. MiR-92a-3p mimic, inhibitor and ACAA1 vector were constructed and transfected into LoVo cells. Results: 25-HC promotes CRC cells migration, invasion, and metastasis both in vitro and in vivo without affecting cells proliferation and apoptosis, accompanied by the upregulation of the expressions of MMPs and epithelial-mesenchymal transition (EMT) related markers. Mechanistically, miR-92a-3p expression is significantly elevated after 25-HC stimulation, while ACAA1 expression is down-regulated and negatively associated with tumor progression. Luciferase reporter assay confirms that miR-92a-3p could directly target ACAA1. Subsequent investigation indicates that nuclear factor (NF)-κB signaling is the downstream pathways of miR-92a-3p-ACAA1 axis in CRC cells. Conclusions: 25-HC promotes CRC cells metastasis by regulating cells migration, invasion and EMT through miR-92a-3p/ACAA1/NF-κB pathway.Trial registration: The current study was approved by the Ethics Committee of the First Affiliated Hospital, Zhejiang University on March22, 2018. The permission number was 2018-706 and 2020-1000.