Cholest-4-en-3-one attenuates TGF-β responsiveness by inducing TGF-β receptors degradation in Mv1Lu cells and colorectal adenocarcinoma cells

• Published in: Journal of receptors and signal transduction 2017-03, Vol.37 (2), p.189-199
• Main Authors: Chen, Chun-Lin, Wu, Deng-Chyang, Liu, Min-Yun, Lin, Ming-Wei, Huang, Hung-Tu, Huang, Yaw-Bin, Chen, Li-Chai, Chen, Yu-Yu, Chen, Jih-Jung, Yang, Pei-Hua, Kao, Yu-Chen, Chen, Pei-Yu
• Format: Article
• Language: English
• Subjects: Animals; Cholest-4-en-3-one; Cholestenones - administration & dosage; colorectal cancer; Colorectal Neoplasms - drug therapy; Colorectal Neoplasms - genetics; Colorectal Neoplasms - pathology; Epithelial Cells - pathology; HT29 Cells; Humans; lipid raft; Lung - pathology; Membrane Microdomains - drug effects; Membrane Microdomains - genetics; Membrane Microdomains - metabolism; Mink - genetics; Phosphorylation; Plasminogen Activator Inhibitor 1 - biosynthesis; Plasminogen Activator Inhibitor 1 - genetics; Protein-Serine-Threonine Kinases - biosynthesis; Protein-Serine-Threonine Kinases - genetics; Proteolysis - drug effects; Receptors, Transforming Growth Factor beta - biosynthesis; Receptors, Transforming Growth Factor beta - genetics; Signal Transduction - drug effects; TGF-beta; Transforming Growth Factor beta1 - biosynthesis; Transforming Growth Factor beta1 - genetics
• ISSN: 1079-9893; 1532-4281
• DOI: 10.1080/10799893.2016.1203944

Purpose: The transforming growth factor-beta (TGF-β) pathway is an important in the initiation and progression of cancer. Due to a strong association between an elevated colorectal cancer risk and increase fecal excretion of cholest-4-en-3-one, we aim to determine the effects of cholest-4-en-3-one on TGF-β signaling in the mink lung epithelial cells (Mv1Lu) and colorectal cancer cells (HT29) in vitro. Methods: The inhibitory effects of cholest-4-en-3-one on TGF-β-induced Smad signaling, cell growth inhibition, and the subcellular localization of TGF-β receptors were investigated in epithelial cells using a Western blot analysis, luciferase reporter assays, DNA synthesis assay, confocal microscopy, and subcellular fractionation. Results: Cholest-4-en-3-one attenuated TGF-β signaling in Mv1Lu cells and HT29 cells, as judged by a TGF-β-specific reporter gene assay of plasminogen activator inhibitor-1 (PAI-1), Smad2/3 phosphorylation and nuclear translocation. We also discovered that cholest-4-en-3-one suppresses TGF-β responsiveness by increasing lipid raft and/or caveolae accumulation of TGF-β receptors and facilitating rapid degradation of TGF-β and thus suppressing TGF-β-induced signaling. Conclusions: Our results suggest that cholest-4-en-3-one inhibits TGF-β signaling may be due, in part to the translocation of TGF-β receptor from non-lipid raft to lipid raft microdomain in plasma membranes. Our findings also implicate that cholest-4-en-3-one may be further explored for its potential role in colorectal cancer correlate to TGF-β deficiency.