Gene expression profile of the human T-ALL cell line JURKAT after TYK2 and STAT1 knockdown

Targeted molecular therapy has yielded remarkable outcomes in certain cancers, but specific therapeutic targets remain elusive for many others. As a result of two independent RNA interference (RNAi) screens, we identified pathway dependence on a member of the JAK tyrosine kinase family, TYK2, and its downstream effector STAT1 in T-cell acute lymphoblastic leukemia (T-ALL). Gene knockdown experiments consistently demonstrated TYK2 dependence in both T-ALL primary specimens and cell lines, and a small-molecule inhibitor of JAK kinase activity induced T-ALL cell death. Activation of this TYK2-STAT1 pathway in T-ALL cell lines occurs by gain-of-function TYK2 mutations or activation of IL-10 receptor signaling, and this pathway mediates T-ALL cell survival through upregulation of the anti-apoptotic protein BCL2. These findings indicate that in many T-ALL cases, the leukemic cells are dependent upon the TYK2-STAT1-BCL2 pathway for continued survival, supporting the development of molecular therapies targeting TYK2 and other components of this pathway.

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Sanda T, Tyner JW, Gutierrez A, Ngo VN, Glover J, Chang BH, Yost A, Ma W, Fleischman AG, Zhou W, Yang Y, Kleppe M, Ahn Y, Tatarek J, Kelliher MA, Neuberg DS, Levine RL, Moriggl R, Müller M, Gray NS, Jamieson CH, Weng AP, Staudt LM, Druker BJ, Look AT