CDH1-involved Ubiquitination of SIRT5 Promotes the Entry of Colorectal Cancer Cells into Quiescence and Enhances Cell Stemness

Background: This study explored whether the cell cycle regulator cadherin 1 (CDH1) impacts colorectal cancer cell cycle and stemness via mediating ubiquitination of sirtuin 5 (SIRT5). Methods: We first constructed CDH1 overexpression plasmid and small interfering RNA against SIRT5 (siSIRT5) and transfected them into HCT116/HT29 cells, followed by transfection efficiency verification. The effect of CDH1 on Cyclin F/SIRT5/CDH1 protein levels in HCT116/HT29 cells was verified by Western blot. After up-regulation of CDH1, changes in SIRT5 ubiquitination (immunoprecipitation), cell cycle (cell cycle kit), proliferation (5-Bromodeoxyuridine assay), and stemness marker expressions (qRT-PCR) in HCT116/HT29 cells were detected. Rescue assays were performed to examine cell proliferation and stemness marker expressions. Results: Overexpression of CDH1 decreased Cyclin F expression and increased SIRT5 and CDH1 expressions in HCT116/HT29 cells. Up-regulation of CDH1 suppressed SIRT5 ubiquitination, promoted G0/G1 phase blockage in HCT116/HT29 cells, boosted cell proliferation into quiescence and enhanced cell stemness. siSIRT5 counteracted the regulatory effect of CDH1 overexpression on colorectal cancer cells. Conclusion: CDH1 promotes the entry of colorectal cancer cells into quiescence and enhances stemness by dampening SIRT5 ubiquitination.