IL-6 increases SDCBP expression, cell proliferation, and cell invasion by activating JAK2/STAT3 in human glioma cells

Syndecan-binding protein (SDCBP), which is induced by tumor necrosis factor-α and interferon-γ, controls the proliferation and invasion of several different types of cancer cells. Interleukin-6 (IL-6) is known to play an important role in the glioma cell growth and invasion. The present study aimed to investigate the relationship between IL-6 and SDCBP in glioma cells. SDCBP expression was knocked down in two glioma cell lines (T98G and U87) by small interfering RNA (siRNA) transfection. Cell proliferation and invasion were significantly repressed following SDCBP knockdown, and there was a positive correlation between SDCBP and IL-6 expression levels in glioma tissues. IL-6 stimulation dose- and time-dependently induced SDCBP expression at both mRNA and protein levels. Furthermore, pre-treatment with the Janus kinase 2 (JAK2) inhibitor AG490 abolished the IL-6-induced SDCBP expression, suggesting that the effect of IL-6 on SDCBP transcription is dependent on JAK2/signal transducer and activator of transcription 3 (STAT3) signaling. Finally, IL-6 did not stimulate glioma cell growth or invasion when SDCBP expression was suppressed. In summary, our results suggest that IL-6 promotes glioma cell proliferation and invasion by inducing SDCBP expression, which is mediated by JAK2/STAT3 signaling.