FAM46B inhibits cell proliferation and cell cycle progression in prostate cancer through ubiquitination of β-catenin

FAM46B is a member of the family with sequence similarity 46. Little is known about the expression and functional role (s) of FAM46B in prostate cancer (PC). In this study, the expression of FAM46B expression in The Cancer Genome Atlas, GSE55945, and an independent hospital database was measured by bioinformatics and real-time PCR analysis. After PC cells were transfected with siRNA or a recombinant vector in the absence or presence of a beta-catenin signaling inhibitor (XAV-939), the expression levels of FAM46B, C-myc, Cyclin D1, and beta-catenin were measured by western blot and realtime PCR. Cell cycle progression and cell proliferation were measured by flow cytometry and the CCK-8 assay. The effects of FAM46B on tumor growth and protein expression in nude mice with PC tumor xenografts were also measured. Our results showed that FAM46B was downregulated but that beta-catenin was upregulated in patients with PC. FAM46B silencing promoted cell proliferation and cell cycle progression in PC, which were abrogated by XAV-939. Moreover, FAM46B overexpression inhibited PC cell cycle progression and cell proliferation in vitro and tumor growth in vivo. FAM46B silencing promoted beta-catenin protein expression through the inhibition of beta-catenin ubiquitination. Our data clearly show that FAM46B inhibits cell proliferation and cell cycle progression in PC through ubiquitination of beta-catenin.