Knockdown of S100B in WM115 malignant melanoma cells increases IL6 expression and STAT3 phosphorylation.

(A) qRT-PCR analysis was done to compare the IL6 mRNA levels in non-targeting scrambled and stable S100B knockdown WM115 cell lines, respectively and (B) an IL6 ELISA was used to detect secreted IL6 levels 24 and 48 hours after the introduction of new media. Both IL6 mRNA and secreted protein levels increase significantly upon knockdown of S100B (n = 4, mean ± SD; *, P < 0.05; ****, P < 0.0001). (C) Immunoblot analysis of shS100B WM115 cells shows little or no detectable S100B protein compared to shSCR WM115. In addition, levels of total STAT3 remain constant while there is a significant increase in p-STAT3 (Tyr705) in shS100B versus shSCR WM115 as shown by the average densitometry measurements of the p-STAT3 (D) (n = 3, mean ± SD; *, P < 0.05).