Abstract:
Nasopharyngeal carcinoma (NPC) is a type of neoplasm that is highly prevalent in East Asia and Africa with Epstein-Barr virus (EBV), genetic, and dietary factors being implicated as possible aetiologic factors. There have been studies conducted to examine the association of cytokines with the metastasis and invasion properties of cancer cells but the effect is still unclear yet in NPC. In the present study, the roles of EBV latent membrane protein-1 (LMP1) with Interleukin-6 (IL-6), Interleukin-10 (IL-10) and transforming growth factor-beta 1 (TGF-β1) in the metastasis of NPC were investigated. TW01 cells expressing LMP1 (TW01-LMP1) were established via lipofection of LMP1 gene into TW01 cells. These cells were treated with 100 pg/ml IL-6, 1000 pg/ml IL-10 and 100 pg/ml TGF-β1, separately and also in combination at their respective concentration for 48 hours. The cells were then subjected to laminin adhesion assay and later on enzyme-linked immunosorbent assay (ELISA) for the study of matrix metalloproteinase-3 (MMP-3), MMP-9 and vascular endothelial growth factor (VEGF) protein expression. The migration and apoptotic properties of the treated cells were also analysed using scratch test and caspase-3 apoptosis assay. Expression of bmi-1 and ngx6 gene was investigated using real time reverse transcriptase polymerase chain reaction. TW01-LMP1 cells treated with IL-6 (100 pg/ml) showed significant decreases in laminin attachment (p <0.05). The expression of MMP-3 and VEGF was also up-regulated with the presence of LMP1 (p <0.05). Besides that, IL-6 was also found to significantly up-regulated the expression of MMP-9 in NPC cells (p <0.05). In contrast, the presence of IL-10 significantly enhanced the adherence of TW01-LMP1 cells towards laminin (p <0.05). Treatment of TW01-LMP1 with IL-6, IL-10 and TGF-β1 resulted in increased migration by 3.3, 2.5 and 3-fold respectively. TW01 cells were able to evade apoptosis when LMP1 was being expressed (p < 0.05). In conclusion, IL-6 was suggested to promote metastasis in the presence of LMP1 and laminin by up-regulating the expression of MMP-9, bmi-1 gene, enhancing the cell migration and down-regulating the expression of ngx6 gene.
