TY - JOUR
T1 - Enhanced IL-6/IL-6R Signaling Promotes Growth and Malignant Properties in EBV-Infected Premalignant and Cancerous Nasopharyngeal Epithelial Cells
AU - Zhang, Guitao
AU - Tsang, Chi Man
AU - Deng, Wen
AU - Yip, Yim Ling
AU - Lui, Vivian Wai Yan
AU - Wong, Sze Chuen Cesar
AU - Cheung, Annie Lai Man
AU - Hau, Pok Man
AU - Zeng, Musheng
AU - Lung, Maria Li
AU - Chen, Honglin
AU - Lo, Kwok Wai
AU - Takada, Kenzo
AU - Tsao, Sai Wah
PY - 2013/5/1
Y1 - 2013/5/1
N2 - Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infection. However, the exact role of EBV in NPC pathogenesis remains elusive. Activation of signal transducer and activator of transcription 3 (STAT3) is common in human cancers including NPC and plays an important role in the pathogenesis and progression of human cancers. Interleukin-6 (IL-6), a major inflammatory cytokine, is a potent activator of STAT3. In this study, we report that EBV-infected immortalized nasopharyngeal epithelial (NPE) cells often acquire an enhanced response to IL-6-induced STAT3 activation to promote their growth and invasive properties. Interestingly, this enhanced IL-6/STAT3 response was mediated by overexpression of IL-6 receptor (IL-6R). Furthermore, IL-6R overexpression enhanced IL-6-induced STAT3 activation in uninfected immortalized NPE cells in vitro, and promoted growth and tumorigenicity of EBV-positive NPC cell line (C666-1) in vivo. Moreover, it is shown for the first time that IL-6R was overexpressed in clinical specimens of NPC. IL-6 expression could also be strongly detected in the stromal cells of NPC and a higher circulating level of IL-6 was found in the sera of advance-staged NPC patients compared to the control subjects. Therefore, IL-6R overexpression, coupled with enhanced IL-6/STAT3 signaling may facilitate the malignant transformation of EBV-infected premalignant NPE cells into cancer cells, and enhance malignant properties of NPC cells.
AB - Nasopharyngeal carcinoma (NPC) is etiologically associated with Epstein-Barr virus (EBV) infection. However, the exact role of EBV in NPC pathogenesis remains elusive. Activation of signal transducer and activator of transcription 3 (STAT3) is common in human cancers including NPC and plays an important role in the pathogenesis and progression of human cancers. Interleukin-6 (IL-6), a major inflammatory cytokine, is a potent activator of STAT3. In this study, we report that EBV-infected immortalized nasopharyngeal epithelial (NPE) cells often acquire an enhanced response to IL-6-induced STAT3 activation to promote their growth and invasive properties. Interestingly, this enhanced IL-6/STAT3 response was mediated by overexpression of IL-6 receptor (IL-6R). Furthermore, IL-6R overexpression enhanced IL-6-induced STAT3 activation in uninfected immortalized NPE cells in vitro, and promoted growth and tumorigenicity of EBV-positive NPC cell line (C666-1) in vivo. Moreover, it is shown for the first time that IL-6R was overexpressed in clinical specimens of NPC. IL-6 expression could also be strongly detected in the stromal cells of NPC and a higher circulating level of IL-6 was found in the sera of advance-staged NPC patients compared to the control subjects. Therefore, IL-6R overexpression, coupled with enhanced IL-6/STAT3 signaling may facilitate the malignant transformation of EBV-infected premalignant NPE cells into cancer cells, and enhance malignant properties of NPC cells.
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U2 - 10.1371/journal.pone.0062284
DO - 10.1371/journal.pone.0062284
M3 - Article
C2 - 23658720
AN - SCOPUS:84877040826
SN - 1932-6203
VL - 8
JO - PloS one
JF - PloS one
IS - 5
M1 - e62284
ER -
