Figure 4. miR-155 expression in response to STAT5-activating cytokines. (A) Incubation with IL-2 (10³U/ml) for 24 h increased expression of BIC (left) and miR-155 (right) in non-malignant MyLa1850 (top, 1.7-fold increase, p < 0.05) as well as malignant SeAx T cells (bottom, 1.5-fold increase, p < 0.02) as shown by qPCR, and was accompanied by induction of STAT5 phosphorylation. (B) In primary T cells obtained from two SS patients (P3 and P4), incubation with IL-2 (2 × 10³ U/ml) for 24 h resulted in an increase of miR-155 in both malignant (CD26⁻) and non-malignant (CD26⁺) populations. The increase was stronger in T cells isolated from P4; however, both samples showed elevated levels of miR-155 in response to IL-2. (C) In PBMCs from a healthy donor, a 24 h incubation with IL-2 (2 × 10³U/ml) led to a 2.3-fold increase of miR-155. (D) Incubation of non-malignant MySi T cells with IL-15 (25 ng/ml) for 24h resulted in increased levels of BIC (2-fold) and miR-155 (1.5-fold). p values were obtained from Student’s t-test. *Indicates a significance of p < 0.05.