Hodgkin-Reed/Sternberg (HRS) cells of classical Hodgkin lymphoma show aberrant expression and activation of several receptor tyrosine kinases (RTK) in the majority of cases. Therefore, we tested whether tyrosine kinase inhibitors (TKI) already in clinical use or late stages of clinical trials have antiproliferative effects on HRS cell lines and evaluated the targets, affected signaling pathways, and mechanisms of cell death and resistance. Sorafenib and lestaurtinib had antiproliferative effects on HRS cell lines at concentrations achievable in patients. Sorafenib inhibited platelet-derived growth factor receptor (PDGFR) a, TRKA and RON, caused decreases in total and phosphorylated amounts of several signaling molecules, and provoked caspase-3-independent cell death, most likely due to endoplasmic reticulum stress as indicated by upregulation of GADD34 and GADD153 and phosphorylation of PERK. Lestaurtinib inhibited TRKA, PDGFRa, RON, and JAK2 and had only a cytostatic effect. Besides deactivation, lestaurtinib also caused activation of signaling pathways. It caused increases in CD30L and TRAIL expression, and CD30L/CD30 signaling likely led to the observed concomitant activation of extracellular signal-regulated kinase 1/2 and the alternative NF-kB pathway. These data disclose the possible use of sorafenib for the treatment of Hodgkin lymphoma and highlight NF-kB activation as a potential novel mechanism of resistance toward TKIs.

<p>PDF file - Supplementary Table S1. Primary antibodies for Western blot analysis. Supplementary Table S2. Primer sequences for qRT-PCR. Supplementary Table S3. TKIs and conventional chemotherapeutics used in this study. Supplementary Table S4. Sensitivity of Hodgkin-Reed/Sternberg cell lines to tyrosine kinase inhibitors (TKIs) at concentrations achievable in patients. Supplementary Table S5. Amount of phosphorylated RTK in relation to total RTK amount. Supplementary Table S6. Genes with increased expression upon lestaurtinib treatment of KM-H2 as determined by GeneChip Human 1.0 ST Arrays. Supplementary Table S7. Genes with decreased expression upon lestaurtinib treatment of KM-H2 as determined by GeneChip Human 1.0 ST Arrays. Supplementary Table S8. Gene ontology annotation of differentially expressed genes in lestaurtinib treated KM-H2 cells.</p>

<p>PDF file - 28K, Supplementary Figure S1. Effect of sorafenib treatment on GADD34 and GADD153 mRNA expression in different cell lines.</p>

<p>PDF file - 29K, Supplementary Figure S2. Effect of lestaurtinib treatment on TNFSF8 mRNA expression in HRS and ALCL cell lines.</p>