Epstein-Barr virus induces human nasopharyngeal epithelial cells to escape from the replicative senescence.
OBJECTIVE
To observe the biological changes of primary human nasopharyngeal epithelial cells in the early stage of immortalization.


METHODS
The morphological changes of nasopharyngeal epithelial cells were observed by phase contrast microscopy, and the activity profile of senescence-associated beta-galactosidase (SA-beta-Gal) was detected by SA-beta-Gal staining. The expression of p16(INK4a) protein was tested by immunochemical assay, and the life span in vitro of nasopharyngeal epithelial cells was calculated as population doublings. In addition, the expression of Epstein-Barr (EB) virus latent membrane protein 1 (LMP1) was also detected by immunofluorescence staining.


RESULTS
Morphologically, cells treated with EB virus and 12-o-tetradecanoyl-phorbol-13-acetate (TPA) formed multi-layer foci, and their cellular life span in vitro was extended (about 155 days of culture). A low percentage of cells (about 4.8%) expressed SA-beta-Gal activity at late primary culture, and did not always express p16(INK4a) protein in the progression of culture.


CONCLUSIONS
Nasopharyngeal epithelial cells treated with EB virus in cooperation with TPA can pass through the stage of senescence and enter the early stage of immortalization. Some changes of phenotype occur in these cells. Our results provide data for further studying the mechanism of immortalization and the establishment of a human nasopharyngeal epithelial cell line.
Yang
Jing
J
Cancer Research Institute, Hunan Medical University, Changsha 410078, China. ycao98@public.cs.hn.cn
Tang
Faqing
F
Gu
Huanhua
H
Deng
Xiyun
X
Weng
Xinxian
X
Tang
Min
M
Cao
Ya
Y
D002472:Cell Transformation, Viral; D016922:Cellular Senescence; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis; D004847:Epithelial Cells / Q000502:physiology / Q000821:virology; D004854:Herpesvirus 4, Human / Q000502:physiology*; D006801:Humans; D009305:Nasopharynx / Q000166:cytology* / Q000821:virology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D019941:Cyclin-Dependent Kinase Inhibitor p16; D013755:Tetradecanoylphorbol Acetate