title: Development and applications of a nasopharyngeal carcinoma Tet-Off cell line.
abstract: The conditional activation and inactivation of target gene expression in a nasopharyngeal carcinoma (NPC) cell line is beneficial for the study of the roles of NPC-related genes. Based on the Tet-Off Advanced system, a NPC S18 Tet-Off cell line was developed by stable transfection of a pTet-Off Advanced vector (regulator plasmid in Tet-Off Advanced system) into NPC S18 cells. Doxycycline-dependent regulators expressed in the S18 Tet-Off cells were examined by transient and stable transfection of pTRE-Tight-Luc. The S18 Tet-Off-Luc clone selected by stable transfection of pTRE-Tight-Luc into S18 Tet-Off cells expressed firefly luciferase under tight control of doxycycline in a time- and dose-dependent manner. To test applications of the S18 Tet-Off cell line in the study of gene function, the impact of ferritin heavy chain (FTH1) gene on NPC cell growth was examined. The S18 Tet-Off-FTH1 clone was developed by stably transfecting pTRE-Tight-FTH1 (response plasmid harboring FTH1) into S18 Tet-Off cells. FTH1 levels in the S18 Tet-Off-FTH1 clone were semi-quantitatively regulated in response to varying concentrations of doxycycline. A cell proliferation assay showed that a high expression of FTH1 (cells grown in the absence of doxycycline) reduced cell growth, while moderate FTH1 overexpression (cells grown in 0.1 ng/ml doxycycline) had no adverse effect on cell growth. In conclusion, the S18 Tet-Off cell line provides a proven genetic background for convenient access to controllable gene expression in NPC.
authors.affiliation: Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080.
authors.forename: Yu-Peng
authors.initials: YP
authors.lastname: Feng
authors.forename: Qi-Cai
authors.initials: QC
authors.lastname: Liu
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Zhu
authors.forename: Fu-Kang
authors.initials: FK
authors.lastname: Xie
authors.forename: Li
authors.initials: L
authors.lastname: Li