Epstein-Barr virus infection in immortalized nasopharyngeal epithelial cells: regulation of infection and phenotypic characterization.
Epstein-Barr virus (EBV) infection has been postulated to be an early event involved in the pathogenesis of nasopharyngeal carcinomas (NPC). The lack of representative premalignant nasopharyngeal epithelial cell system for EBV infection has hampered research investigation into the regulation and involvement of EBV infection in NPC pathogenesis. We have compared the efficiency of EBV infection in nasopharyngeal epithelial cells with different biological properties including immortalized, primary and cancerous nasopharyngeal epithelial cells. EBV infection could be achieved in all the nasopharyngeal epithelial cells examined with variable infection rate. TGF-beta effectively enhanced EBV infection into nasopharyngeal epithelial cells both in the immortalized and primary nasopharyngeal epithelial cells. Stable infection of EBV was achieved in a telomerase-immortalized nasopharyngeal epithelial cell line, NP460hTert. The expression pattern of EBV-encoded genes and biological properties of this EBV infected cell line on long-term propagation were monitored. The EBV-infected nasopharyngeal epithelial cells acquired anchorage-independent growth and exhibited invasive growth properties on prolonged propagation. A distinguished feature of this EBV-infected nasopharyngeal epithelial cell model was its enhanced ability to survive under growth factor and nutrient starvation. This was evidenced by the suppressed activation of apoptotic markers and sustained activation of pAkt of EBV-infected cells compared to control cells under nutrient starvation. Examination of cytokine profiles of EBV-infected NP460hTert cells to nutrient and growth factor deprivation revealed upregulation of expression of MCP-1 and GRO-alpha. The establishment of a stable EBV infection model of premalignant nasopharyngeal epithelial cells will facilitate research investigation into the pathogenic role of EBV in NPC development.
Tsang
Chi Man
CM
Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
Zhang
Guitao
G
Seto
Eri
E
Takada
Kenzo
K
Deng
Wen
W
Yip
Yim Ling
YL
Man
Cornelia
C
Hau
Pok Man
PM
Chen
Honglin
H
Cao
Ya
Y
Lo
Kwok Wai
KW
Middeldorp
Jaap M
JM
Cheung
Annie Lai Man
AL
Tsao
Sai Wah
SW
D000818:Animals; D002460:Cell Line; D002874:Chromosome Mapping; D017931:DNA Primers; D004847:Epithelial Cells / Q000473:pathology / Q000821:virology; D020031:Epstein-Barr Virus Infections / Q000150:complications* / Q000473:pathology; D020869:Gene Expression Profiling; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007621:Karyotyping; D051379:Mice; D008819:Mice, Nude; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000473:pathology*; D009305:Nasopharynx / Q000473:pathology* / Q000821:virology; D010641:Phenotype; D054390:Receptors, CCR2 / Q000235:genetics; D017464:Receptors, Complement 3d / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D054390:Receptors, CCR2; D017464:Receptors, Complement 3d