ABSTRACT
Purpose@#The purpose of this study was to investigate the influences of sex comb on midleg like-2 (SCML2) on hepatocellular carcinoma (HCC) and potentially related mechanisms. @*Materials and Methods@#SCML2 expression in tumor tissues and cells was analyzed using the TCGA database and/or qRT-PCR. The proliferation of HCC cells was detected by CCK-8, colony formation, and EdU assays. The migration and invasion of HCC cells were detected by transwell and wound healing assays. Apoptosis of HCC cells was determined by flow cytometry. Additionally, qRT-PCR and Western blot were used to detect the expression of SCML2 and Wnt/β-catenin/epithelial–mesenchymal transition (EMT) signaling. A xenograft model in mice was established to verify the in vitro findings. @*Results@#We found that SCML2 was highly expressed in HCC tissues and cells and that high expression of SCML2 was correlated with poor prognosis in HCC patients. SCML2 overexpression promoted proliferation, invasion, and migration and repressed apoptosis of HCC cells. The reverse results were obtained in SCML2-silenced cells. Further, we found that SCML2 activated the Wnt/β-catenin/EMT pathway. SCML2 silencing reduced the protein levels of Wnt3a, β-catenin, N-cadherin, Vimentin, and Snail and enhanced E-cadherin protein expression both in vivo and in vitro. @*Conclusion@#SCML2 silencing inhibits the proliferation, migration, and invasion of HCC cells by regulating the Wnt/β-catenin/ EMT pathway.
ABSTRACT
The primary cilium is a microtubule-based sensory organelle. The molecular mechanism that regulates ciliary dynamics remains elusive. Here, we report an unexpected finding that MLN4924, a small molecule inhibitor of NEDD8-activating enzyme (NAE), blocks primary ciliary formation by inhibiting synthesis/assembly and promoting disassembly. This is mainly mediated by MLN4924-induced phosphorylation of AKT1 at Ser473 under serum-starved, ciliary-promoting conditions. Indeed, pharmaceutical inhibition (by MK2206) or genetic depletion (via siRNA) of AKT1 rescues MLN4924 effect, indicating its causal role. Interestingly, pAKT1-Ser activity regulates both ciliary synthesis/assembly and disassembly in a MLN4924 dependent manner, whereas pAKT-Thr determines the ciliary length in MLN4924-independent but VHL-dependent manner. Finally, MLN4924 inhibits mouse hair regrowth, a process requires ciliogenesis. Collectively, our study demonstrates an unexpected role of a neddylation inhibitor in regulation of ciliogenesis via AKT1, and provides a proof-of-concept for potential utility of MLN4924 in the treatment of human diseases associated with abnormal ciliogenesis.