TY - JOUR
T1 - Epstein-Barr virus infection to Epstein-Barr virus-negative nasopharyngeal carcinoma cell line TW03 enhances its tumorigenicity
AU - Teramoto, Norihiro
AU - Maeda, Akihiko
AU - Kobayashi, Keita
AU - Hayashi, Kazuhiko
AU - Oka, Takashi
AU - Takahashi, Kiyoshi
AU - Takada, Kenzo
AU - Klein, Georg
AU - Akagi, Tadaatsu
N1 - Funding Information:
We thank the following for their skillful technical assistance: Karin Kvarnung, Sachiyo Onoda, Mutsumi Ok-abe, Reiko Endo, Yoshie Sakamoto, Hiromi Naka-mura, Rika Hayashi, and Miyuki Shiotani. T. N. and M. A. are recipients of a fellowship from the Cancer Research Institute in New York.
PY - 2000/3
Y1 - 2000/3
N2 - Almost all nasopharyngeal carcinomas (NPCs) are infected by Epstein-Barr virus (EBV), but most ex vivo NPC cells lose EBV genomes during passages. In this study, an EBV-negative NPC cell line, TW03, established from EBV- carrying NPC was reinfected with EBV by cocultivation with irradiated Akata cells carrying recombinant EBV containing a neomycin-resistant gene. The reinfected EBV (+) TW03 cells expressed EBERs and EBNA1, but not EBNA2, lytic proteins (ZEBRA and EA-D), or LMP1. They had an epithelial appearance similar to that of EBV (-) TW03 cells. The doubling times of EBV (+) and EBV () TW03 cells were almost identical. However, the EBV (+) TW03 cells formed larger colonies with ragged contours in anchorage-independent cultures. An in vitro invasion assay showed that EBV (+) TW03 cells had a higher invasive activity than EBV () TW03 cells (p < 0.01). Both EBV () and EBV (+) TW03 cells formed poorly differentiated squamous cell carcinomas in SCID and nude mice. EBV (+) TW03 cells showed a higher tumorigenicity to nude mice (12 of 13) than EBV (- ) TW03 cells (1 of 9) (p < 0.001). In the severe combined immunodeficiency (SCID) tumors of EBV (+) TW03 cells, not all of the tumor cells were EBER-1 positive. EBER-1 was more frequently detected in the peripheral regions and daughter nodules of the tumors than in the central areas. The microdissection polymerase chain reaction showed that the EBER-1 -negative TW03 cells in the EBV (+) TW03 SCID tumors lost EBV genomes. EBER-1-negative cells showed as high a rate of Ki-67 positivity as EBER-1-positive cells, indicating that the former were proliferating rather than dead or dying. In horny pearls, keratinizing cells were ZEBRA-positive and EBER-negative. Loss of EBV genomes was not associated with squamous differentiation. These data indicated that reinfection of EBV promotes the tumorigenicity of EBV (-) TW03 cells by enhancing the invading activity.
AB - Almost all nasopharyngeal carcinomas (NPCs) are infected by Epstein-Barr virus (EBV), but most ex vivo NPC cells lose EBV genomes during passages. In this study, an EBV-negative NPC cell line, TW03, established from EBV- carrying NPC was reinfected with EBV by cocultivation with irradiated Akata cells carrying recombinant EBV containing a neomycin-resistant gene. The reinfected EBV (+) TW03 cells expressed EBERs and EBNA1, but not EBNA2, lytic proteins (ZEBRA and EA-D), or LMP1. They had an epithelial appearance similar to that of EBV (-) TW03 cells. The doubling times of EBV (+) and EBV () TW03 cells were almost identical. However, the EBV (+) TW03 cells formed larger colonies with ragged contours in anchorage-independent cultures. An in vitro invasion assay showed that EBV (+) TW03 cells had a higher invasive activity than EBV () TW03 cells (p < 0.01). Both EBV () and EBV (+) TW03 cells formed poorly differentiated squamous cell carcinomas in SCID and nude mice. EBV (+) TW03 cells showed a higher tumorigenicity to nude mice (12 of 13) than EBV (- ) TW03 cells (1 of 9) (p < 0.001). In the severe combined immunodeficiency (SCID) tumors of EBV (+) TW03 cells, not all of the tumor cells were EBER-1 positive. EBER-1 was more frequently detected in the peripheral regions and daughter nodules of the tumors than in the central areas. The microdissection polymerase chain reaction showed that the EBER-1 -negative TW03 cells in the EBV (+) TW03 SCID tumors lost EBV genomes. EBER-1-negative cells showed as high a rate of Ki-67 positivity as EBER-1-positive cells, indicating that the former were proliferating rather than dead or dying. In horny pearls, keratinizing cells were ZEBRA-positive and EBER-negative. Loss of EBV genomes was not associated with squamous differentiation. These data indicated that reinfection of EBV promotes the tumorigenicity of EBV (-) TW03 cells by enhancing the invading activity.
UR - http://www.scopus.com/inward/record.url?scp=0034123983&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034123983&partnerID=8YFLogxK
U2 - 10.1038/labinvest.3780035
DO - 10.1038/labinvest.3780035
M3 - Article
C2 - 10744066
AN - SCOPUS:0034123983
SN - 0023-6837
VL - 80
SP - 303
EP - 312
JO - Laboratory Investigation
JF - Laboratory Investigation
IS - 3
ER -