Effects of silencing farnesyltransferase on the migration, invasion, and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells.

Abstract

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. 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. 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). 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.