RAB1B, a member of the RAS oncogene family, was significantly down-regulated in highly metastatic breast cancer cells. Moreover, down-regulation of RAB1B was also found to promote the proliferation and migration of TNBC cells in vitro and in vivo. Mechanistically, loss of RAB1B resulted in elevated expression of TGF-beta receptor 1 (TbetaR1) through decreased degradation of ubiquitin, increased levels of phosphorylated SMAD3 and TGF-beta-induced epithelial-mesenchymal transition (EMT). Furthermore, low RAB1B expression correlated with poor prognosis in breast cancer patients.RAB1B acts as a metastasis suppressor in TNBC by regulating the TGF-beta/SMAD signaling pathway and RAB1B may serve as a novel biomarker of prognosis and the response to anti-tumor therapeutics for patients with TNBC.
RAB1B, member RAS oncogene family