Induction of interleukin-8 by Epstein-Barr virus latent membrane protein-1 and its correlation to angiogenesis in nasopharyngeal carcinoma.
OBJECTIVE
The EBV latent membrane protein-1 (LMP-1) is a multifunctional protein. Recently, the contribution of LMP-1 to the metastasis of nasopharyngeal carcinoma (NPC) has been suggested. Angiogenesis is a key step for metastasis. Thus, the association of LMP-1 to neovascularization of NPC was examined in this study.


METHODS
The association of LMP-1 to angiogenesis in 39 patients with NPC was evaluated by immunohistochemical study, and then induction of angiogenic factors by LMP-1 was examined by ELISA and luciferase reporter assay.


RESULTS
In an immunohistochemical study, the expression of LMP-1 was significantly correlated to microvessel counts (P = 0.0003), suggesting that LMP-1 may induce some angiogenic factors. Therefore, we studied the relationship between LMP-1 expression and interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) expression by immunohistochemical analysis. IL-8, VEGF, and bFGF expression were correlated to microvessel counts, but only IL-8 expression was significantly correlated to LMP-1 expression (P < 0.0001). Transfection with LMP-1 expression plasmid induced IL-8 protein expression in C33A cells. The expression of LMP-1 transactivated IL-8 promoter, as demonstrated by IL-8 promoter luciferase reporter assay. Mutation of the nuclear factor kappaB responsive element in the IL-8 promoter region completely abolished transactivation by LMP-1, whereas mutation of the activator protein responsive element did not affect promoter activity.


CONCLUSIONS
These results suggested that LMP-1 induces expression of IL-8 through the nuclear factor kappaB binding site, which may contribute in part to angiogenesis in NPC.
Yoshizaki
T
T
Department of Otolaryngology, School of Medicine, Kanazawa University, Kanazawa 920-8641, Japan. tomoy@med.kanazawa-u.ac.jp
Horikawa
T
T
Qing-Chun
R
R
Wakisaka
N
N
Takeshita
H
H
Sheen
T S
TS
Lee
S Y
SY
Sato
H
H
Furukawa
M
M
D043925:Angiogenesis Inducing Agents / Q000032:analysis; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001808:Blood Vessels / Q000473:pathology; D020031:Epstein-Barr Virus Infections / Q000473:pathology / Q000821:virology; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000098:blood supply* / Q000821:virology; D009389:Neovascularization, Pathologic / Q000473:pathology* / Q000821:virology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014763:Viral Matrix Proteins / Q000096:biosynthesis* / Q000235:genetics; D014841:von Willebrand Factor / Q000032:analysis
D043925:Angiogenesis Inducing Agents; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D016209:Interleukin-8; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D018808:Transcription Factor AP-1; D014763:Viral Matrix Proteins; D014841:von Willebrand Factor; D008156:Luciferases