Suppression of Epstein-Barr nuclear antigen 1 (EBNA1) by RNA interference inhibits proliferation of EBV-positive Burkitt's lymphoma cells.
OBJECTIVE
Epstein-Barr virus (EBV) is associated with the development of several lymphoid and epithelial malignancies, including Burkitt's lymphoma. The EBV latent protein, EBV Nuclear Antigen 1 (EBNA1), is detectable in almost all types of EBV-associated tumors and is essential for replication and maintenance of the latent episome of EBV. We here examined whether the RNA interference (RNAi) technique could be employed to suppress expression of EBNA1 in EBV-positive Burkitt's lymphoma cells.


METHODS
A Raji cell line expressing small hairpin RNAs (shRNAs) against EBNA1 was established and EBNA1 mRNA level was determined by real-time RT-PCR analysis. We investigated the effects of EBNA1 silence on lymphoma cell growth and cell cycle progression.


RESULTS
Transfection of an EBNA1 RNAi plasmid resulted in substantial loss of EBNA1 mRNA and significantly inhibited proliferation of Raji cells relative to the control plasmid case. Suppression of EBNA1 was also associated with downregulation of EBV oncogene EBNA2, a decreased PCNA labeling index and increased G0/G1 fraction in cell cycle analysis.


CONCLUSIONS
These findings point to potential therapeutic applications for vector-mediated siRNA delivery to control EBV-associated malignant disorders.
Hong
Mei
M
Department of Pathology, School of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, 930-0194, Toyama, Japan.
Murai
Yoshihiro
Y
Kutsuna
Tomohiko
T
Takahashi
Hiroyuki
H
Nomoto
Kazuhiro
K
Cheng
Chun-Mei
CM
Ishizawa
Shin
S
Zhao
Qing-Li
QL
Ogawa
Ryohei
R
Harmon
Brian V
BV
Tsuneyama
Koichi
K
Takano
Yasuo
Y
D017209:Apoptosis; D001483:Base Sequence; D015153:Blotting, Western; D002051:Burkitt Lymphoma / Q000473:pathology* / Q000821:virology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D015967:Gene Expression Regulation, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D010957:Plasmids; D034622:RNA Interference; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D014162:Transfection; D014764:Viral Proteins
C402641:EBNA-2 protein, Human herpesvirus 4; D019309:Epstein-Barr Virus Nuclear Antigens; D012333:RNA, Messenger; D014764:Viral Proteins; C417029:EBV-encoded nuclear antigen 1