Figure 6.

Sox2 transcriptional activity correlates with increased invasiveness and contributes to tumorigenicity of ALK⁺ALCL cell lines. Downregulation of Sox2 expression in the Sox2^active subset of Karpas 299 and SUP-M2 cells led to a significant decrease in cell invasiveness (a, c). However, downregulation of Sox2 expression in the Sox2^inactive subset resulted in no significant change (b, d). Furthermore, isolated Karpas 299 Sox2^active cells were significantly more invasive than Sox2^inactive cells (e). Results are expressed in RFU (relative factor unit), which is a measure of cells that have invaded the membrane. The Sox2^active subsets of both Karpas 299 (f) and SUP-M2 (g) showed a significantly higher number of colonies in methylcellulose colony formation assay, as compared with the Sox2^inactive subsets. Data is presented in such a way that the colony numbers of Sox2^inactive subsets were set as 100%. Downregulation of Sox2 expression in the Sox2^active subset of both Karpas 299 (h) and SUP-M2 (j) led to a significant decrease in colony formation. However, downregulation of Sox2 expression in the Sox2^inactive subset resulted in no significant change in both Karpas 299 (i) and SUP-M2 (k). Results shown are representative of three independent experiments.