Abstract
OBJECTIVES: This study aimed to investigate the effects of farnesyltransferase (FTase) on the migration, invasion, and epithelial-mesenchymal transition (EMT) of SACC-LM and SACC-83 cells in salivary adenoid cystic carcinoma and determine the relative mechanism. METHODS: Three small interfering RNA (siRNA) sequences were designed and constructed based on the human FTase gene sequence. The SACC-LM and SACC-83 cells in the logarithmic growth period were used, and the expression of FTase was suppressed by liposomal transient transfection. The tested cells were categorized as the FTase-siRNA-1, FTase-siRNA-2, and FTase-siRNA-3 groups. Both negative control group (NC-siRNA) and blank control group (only transfection reagent was added) were set. The mRNA expression of FTase and HRAS was detected by quantitive real-time polymerase chain reaction, and the silencing efficiency was determined. The expression levels of FTase, HRAS, protein kinase B (AKT), phospho-AKT, p65, phospho-p65 (Ser563), E-cadherin, vimentin, matrix metalloproteinase (MMP)-9 protein, and HRAS membrane protein were detected by Western blot. Transwell assay and wound healing assay were used to detect the invasion and migration abilities of cells. RESULTS: The relative expression of FTase mRNA and protein in the FTase-siRNA-1 group decreased compared with those in the control group (P<0.05). HRAS mRNA and total protein expression had no significant difference (P>0.05), and the relative expression of HRAS membrane protein decreased (P<0.05). The relative expression of E-cadherin increased (P<0.05), vimentin decreased (P<0.05), and MMP-9 decreased (P<0.05). There was no significant difference in the relative expression levels of the RAS/PI3K/AKT/nuclear factor-κB signaling pathway-related proteins AKT and p65 (P>0.05), but the relative expression levels of phospho-AKT and phospho-p65 decreased. The invasion and migration ability of the FTase-siRNA-1 group significantly decreased compared with that in the control group (P<0.05). CONCLUSIONS: Silencing FTase in vitro could effectively inhibit the invasion and migration of SACC-LM and SACC-83 cells by interfering with the localization of the HRAS membrane protein and regulating the RAS/PI3K/AKT/nuclear factor-κB signaling pathway to mediate EMT.