Pharmacologic inhibition of HMGB-1 impairs ALK⁺ cell dissemination in vitro and in vivo. Karpas-299 (Karpas) and SU-DHL-1 cells were incubated or not with 100mM glycyrrhizin. (A) The effect of glycyrrhizin on cell number was measured by following the absorbance at 490nm using the MTS assay. (B) ALK⁺ALCL cells cultured with supernatant from HaCaT cells previously exposed to Karpas-299 or SU-DHL-1 cell culture supernatants supplemented or not with 100mM glycyrrhizin were subjected to the 3D-Matrigel invasion assay described for Figure 5B. (C-E) Karpas-299 cells were subcutaneously injected into SCID mice. Tumor development progressed for 7 days, followed by 7 days of treatment with glycyrrhizin (one 10mg/kg IP injection/d) or PBS. (C) Tumor volume was measured every 2 days using callipers. (D) Histogram represents the mean ± SD of ALK⁺ cells infiltrating the lungs. The number of lymphoma cells was assessed by anti-ALK (rabbit monoclonal SP8) staining. (E) Histopathological examination of lung from xenografted NPM–ALK⁺ Karpas-299 mice shows that HMGB-1 inactivation leads to a decrease in ALK⁺ cells in the lungs. Mice were treated as described previously: lungs were harvested, fixed, and paraffin embedded for immunohistochemical analysis with anti-ALK (Sp8) to visualize invasion by ALK⁺ cells (original magnification, 400×).