Lymphotoxin-mediated activation of the lymphotoxin-β receptor (LTβR; LTBR) has been implicated in cancer, but its role in T-cell acute lymphoblastic leukaemia (T-ALL) has remained elusive. Here we show that the genes encoding lymphotoxin (LT)-α and LTβ (LTA, LTB) are expressed in T-ALL patient samples, mostly of the TAL/LMO molecular subtype, and in the TEL-JAK2 transgenic mouse model of cortical/mature T-ALL (Lta, Ltb). In these mice, expression of Lta and Ltb is elevated in early stage T-ALL. Surface LTα1β2 protein is expressed in primary mouse T-ALL cells, but only in the absence of microenvironmental LTβR interaction. Indeed, surface LT expression is suppressed in leukaemic cells contacting Ltbr-expressing but not Ltbr-deficient stromal cells, both in vitro and in vivo, thus indicating that dynamic surface LT expression in leukaemic cells depends on interaction with its receptor. Supporting the notion that LT signalling plays a role in T-ALL, inactivation of Ltbr results in a significant delay in TEL-JAK2-induced leukaemia onset. Moreover, young asymptomatic TEL-JAK2;Ltbr-/- mice present markedly less leukaemic thymocytes than age-matched TEL-JAK2;Ltbr+/+ mice and interference with LTβR function at this early stage delayed T-ALL development. We conclude that LT expression by T-ALL cells activates LTβR signalling in thymic stromal cells, thus promoting leukaemogenesis. © 2015 John Wiley & Sons Ltd.1715736751Aifantis, I., Gounari, F., Scorrano, L., Borowski, C., von Boehmer, H., Constitutive pre-TCR signaling promotes differentiation through Ca2+ mobilization and activation of NF-kappaB and NFAT (2001) Nature Immunology, 2, pp. 403-409Ammirante, M., Luo, J.-L., Grivennikov, S., Nedospasov, S., Karin, M., B-cell-derived lymphotoxin promotes castration-resistant prostate cancer (2010) Nature, 464, pp. 302-305Ansel, K.M., Ngo, V.N., Hyman, P.L., Luther, S.A., Förster, R., Sedgwick, J.D., Browning, J.L., Cyster, J.G., A chemokine-driven positive feedback loop organizes lymphoid follicles (2000) Nature, 406, pp. 309-314Asnafi, V., Beldjord, K., Libura, M., Villarese, P., Millien, C., Ballerini, P., Kuhlein, E., Macintyre, E., Age-related phenotypic and oncogenic differences in T-cell acute lymphoblastic leukemias may reflect thymic atrophy (2004) Blood, 104, pp. 4173-4180Barata, J.T., Silva, A., Abecasis, M., Carlesso, N., Cumano, A., Cardoso, A.A., Molecular and functional evidence for activity of murine IL-7 on human lymphocytes (2006) Experimental Hematology, 34, pp. 1133-1142Bénézech, C., Mader, E., Desanti, G., Khan, M., Nakamura, K., White, A., Ware, C.F., Caamaño, J.H., Lymphotoxin-β receptor signaling through NF-κB2-RelB pathway reprograms adipocyte precursors as lymph node stromal cells (2012) Immunity, 37, pp. 721-734Boehm, T., Scheu, S., Pfeffer, K., Bleul, C.C., Thymic medullary epithelial cell differentiation, thymocyte emigration, and the control of autoimmunity require lympho-epithelial cross talk via LTbetaR (2003) The Journal of Experimental Medicine, 198, pp. 757-769Brandalise, S.R., Pinheiro, V.R., Aguiar, S.S., Matsuda, E.I., Otubo, R., Yunes, J.A., Pereira, W.V., Viana, M.B., Benefits of the intermittent use of 6-mercaptopurine and methotrexate in maintenance treatment for low-risk acute lymphoblastic leukemia in children: randomized trial from the Brazilian Childhood Cooperative Group - protocol ALL-99 (2010) Journal of Clinical Oncology, 28, pp. 1911-1918Browning, J.L., Ngam-ek, A., Lawton, P., DeMarinis, J., Tizard, R., Chow, E.P., Hession, C., Ware, C.F., Lymphotoxin beta, a novel member of the TNF family that forms a heteromeric complex with lymphotoxin on the cell surface (1993) Cell, 72, pp. 847-856Browning, J.L., Sizing, I.D., Lawton, P., Bourdon, P.R., Rennert, P.D., Majeau, G.R., Ambrose, C.M., Hochman, P.S., Characterization of lymphotoxin-alpha beta complexes on the surface of mouse lymphocytes (1997) Journal of Immunology, 159, pp. 3288-3298Buonamici, S., Trimarchi, T., Ruocco, M.G., Reavie, L., Cathelin, S., Mar, B.G., Klinakis, A., Aifantis, I., CCR7 signalling as an essential regulator of CNS infiltration in T-cell leukaemia (2009) Nature, 459, pp. 1000-1004Carron, C., Cormier, F., Janin, A., Lacronique, V., Giovannini, M., Daniel, M.T., Bernard, O., Ghysdael, J., TEL-JAK2 transgenic mice develop T-cell leukemia (2000) Blood, 95, pp. 3891-3899Cheng, J., Montecalvo, A., Kane, L.P., Regulation of NF-κB induction by TCR/CD28 (2011) Immunologic Research, 50, pp. 113-117Dejardin, E., Droin, N.M., Delhase, M., Haas, E., Cao, Y., Makris, C., Li, Z.-W., Green, D.R., The lymphotoxin-beta receptor induces different patterns of gene expression via two NF-kappaB pathways (2002) Immunity, 17, pp. 525-535Ferrando, A.A., Neuberg, D.S., Staunton, J., Loh, M.L., Huard, C., Raimondi, S.C., Behm, F.G., Look, A.T., Gene expression signatures define novel oncogenic pathways in T cell acute lymphoblastic leukemia (2002) Cancer Cell, 1, pp. 75-87Force, W.R., Walter, B.N., Hession, C., Tizard, R., Kozak, C.A., Browning, J.L., Ware, C.F., Mouse lymphotoxin-beta receptor. Molecular genetics, ligand binding, and expression (1995) Journal of Immunology, 155, pp. 5280-5288Fütterer, A., Mink, K., Luz, A., Kosco-Vilbois, M.H., Pfeffer, K., The lymphotoxin beta receptor controls organogenesis and affinity maturation in peripheral lymphoid tissues (1998) Immunity, 9, pp. 59-70Ganeff, C., Remouchamps, C., Boutaffala, L., Benezech, C., Galopin, G., Vandepaer, S., Bouillenne, F., Dejardin, E., Induction of the alternative NF-κB pathway by lymphotoxin αβ (LTαβ) relies on internalization of LTβ receptor (2011) Molecular and Cellular Biology, 31, pp. 4319-4334Gentleman, R.C., Carey, V.J., Bates, D.M., Bolstad, B., Dettling, M., Dudoit, S., Ellis, B., Zhang, J., Bioconductor: open software development for computational biology and bioinformatics (2004) Genome Biology, 5, p. R80Graux, C., Cools, J., Michaux, L., Vandenberghe, P., Hagemeijer, A., Cytogenetics and molecular genetics of T-cell acute lymphoblastic leukemia: from thymocyte to lymphoblast (2006) Leukemia, 20, pp. 1496-1510Haferlach, T., Kohlmann, A., Wieczorek, L., Basso, G., Kronnie, G.T., Béné, M.-C., De Vos, J., Foà, R., Clinical utility of microarray-based gene expression profiling in the diagnosis and subclassification of leukemia: report from the International Microarray Innovations in Leukemia Study Group (2010) Journal of Clinical Oncology, 28, pp. 2529-2537Haybaeck, J., Zeller, N., Wolf, M.J., Weber, A., Wagner, U., Kurrer, M.O., Bremer, J., Heikenwalder, M., A lymphotoxin-driven pathway to hepatocellular carcinoma (2009) Cancer Cell, 16, pp. 295-308Heinig, K., Gätjen, M., Grau, M., Stache, V., Anagnostopoulos, I., Gerlach, K., Niesner, R.A., Höpken, U.E., Access to follicular dendritic cells is a pivotal step in murine chronic lymphocytic leukemia B-cell activation and proliferation (2014) Cancer Discovery, 4, pp. 1448-1465Heng, T.S.P., Painter, M.W., The Immunological Genome Project: networks of gene expression in immune cells (2008) Nature Immunology, 9, pp. 1091-1094Hikosaka, Y., Nitta, T., Ohigashi, I., Yano, K., Ishimaru, N., Hayashi, Y., Matsumoto, M., Takahama, Y., The cytokine RANKL produced by positively selected thymocytes fosters medullary thymic epithelial cells that express autoimmune regulator (2008) Immunity, 29, pp. 438-450Homminga, I., Pieters, R., Langerak, A.W., de Rooi, J.J., Stubbs, A., Verstegen, M., Vuerhard, M., Meijerink, J.P., Integrated transcript and genome analyses reveal NKX2-1 and MEF2C as potential oncogenes in T cell acute lymphoblastic leukemia (2011) Cancer Cell, 19, pp. 484-497Irla, M., Guerri, L., Guenot, J., Sergé, A., Lantz, O., Liston, A., Imhof, B.A., Reith, W., Antigen recognition by autoreactive CD4+ thymocytes drives homeostasis of the thymic medulla (2012) PLoS One, 7, p. e52591Klug, D.B., Carter, C., Crouch, E., Roop, D., Conti, C.J., Richie, E.R., Interdependence of cortical thymic epithelial cell differentiation and T-lineage commitment (1998) Proceedings of the National Academy of Sciences of the United States of America, 95, pp. 11822-11827Lau, T.-S., Chung, T.-H., Cheung, T.-H., Chan, L.-Y., Cheung, L.-H., Yim, S.-F., Siu, N.-S., Kwong, J., Cancer cell-derived lymphotoxin mediates reciprocal tumour-stromal interactions in human ovarian cancer by inducing CXCL11 in fibroblasts (2014) The Journal of Pathology, 232, pp. 43-56Martins, V.C., Busch, K., Juraeva, D., Blum, C., Ludwig, C., Rasche, V., Lasitschka, F., Rodewald, H.-R., Cell competition is a tumour suppressor mechanism in the thymus (2014) Nature, 509, pp. 465-470Mauri, D.N., Ebner, R., Montgomery, R.I., Kochel, K.D., Cheung, T.C., Yu, G.L., Ruben, S., Ware, C.F., LIGHT, a new member of the TNF superfamily, and lymphotoxin alpha are ligands for herpesvirus entry mediator (1998) Immunity, 8, pp. 21-30Medyouf, H., Gusscott, S., Wang, H., Tseng, J.-C., Wai, C., Nemirovsky, O., Trumpp, A., Weng, A.P., High-level IGF1R expression is required for leukemia-initiating cell activity in T-ALL and is supported by Notch signaling (2011) The Journal of Experimental Medicine, 208, pp. 1809-1822Minuzzo, S., Agnusdei, V., Pusceddu, I., Pinazza, M., Moserle, L., Masiero, M., Rossi, E., Indraccolo, S., DLL4 regulates NOTCH signaling and growth of T acute lymphoblastic leukemia cells in NOD/SCID mice (2015) Carcinogenesis, 36, pp. 115-121Mirandola, L., Chiriva-Internati, M., Montagna, D., Locatelli, F., Zecca, M., Ranzani, M., Basile, A., Chiaramonte, R., Notch1 regulates chemotaxis and proliferation by controlling the CC-chemokine receptors 5 and 9 in T cell acute lymphoblastic leukaemia (2012) The Journal of Pathology, 226, pp. 713-722Moore, N.C., Girdlestone, J., Anderson, G., Owen, J.J., Jenkinson, E.J., Stimulation of thymocytes before and after positive selection results in the induction of different NF-kappa B/Rel protein complexes (1995) Journal of Immunology, 155, pp. 4653-4660Murphy, M., Walter, B.N., Pike-Nobile, L., Fanger, N.A., Guyre, P.M., Browning, J.L., Ware, C.F., Epstein, L.B., Expression of the lymphotoxin beta receptor on follicular stromal cells in human lymphoid tissues (1998) Cell Death and Differentiation, 5, pp. 497-505Rehm, A., Mensen, A., Schradi, K., Gerlach, K., Wittstock, S., Winter, S., Büchner, G., Höpken, U.E., Cooperative function of CCR7 and lymphotoxin in the formation of a lymphoma-permissive niche within murine secondary lymphoid organs (2011) Blood, 118, pp. 1020-1033Remouchamps, C., Boutaffala, L., Ganeff, C., Dejardin, E., Biology and signal transduction pathways of the Lymphotoxin-αβ/LTβR system (2011) Cytokine & Growth Factor Reviews, 22, pp. 301-310dos Santos, N.R., Rickman, D.S., de Reynies, A., Cormier, F., Williame, M., Blanchard, C., Stern, M.-H., Ghysdael, J., Pre-TCR expression cooperates with TEL-JAK2 to transform immature thymocytes and induce T-cell leukemia (2007) Blood, 109, pp. 3972-3981dos Santos, N.R., Williame, M., Gachet, S., Cormier, F., Janin, A., Weih, D., Weih, F., Ghysdael, J., RelB-dependent stromal cells promote T-cell leukemogenesis (2008) PLoS One, 3, p. e2555dos Santos, N.R., Ghezzo, M.N., da Silva, R.C., Fernandes, M.T., NF-κB in T-cell acute lymphoblastic leukemia: oncogenic functions in leukemic and in microenvironmental cells (2010) Cancers, 2, pp. 1838-1860Seach, N., Ueno, T., Fletcher, A.L., Lowen, T., Mattesich, M., Engwerda, C.R., Scott, H.S., Boyd, R.L., The lymphotoxin pathway regulates Aire-independent expression of ectopic genes and chemokines in thymic stromal cells (2008) Journal of Immunology, 180, pp. 5384-5392Shebzukhov, I.V., Kuprash, D.V., Transcriptional regulation of TNF/LT locus in immune cells (2011) Molekuliarnaia Biologiia, 45, pp. 56-67Silva, A., Laranjeira, A.B.A., Martins, L.R., Cardoso, B.A., Demengeot, J., Yunes, J.A., Seddon, B., Barata, J.T., IL-7 contributes to the progression of human T-cell acute lymphoblastic leukemias (2011) Cancer Research, 71, pp. 4780-4789Soulier, J., Clappier, E., Cayuela, J.-M., Regnault, A., García-Peydró, M., Dombret, H., Baruchel, A., Sigaux, F., HOXA genes are included in genetic and biologic networks defining human acute T-cell leukemia (T-ALL) (2005) Blood, 106, pp. 274-286Subramanian, A., Tamayo, P., Mootha, V.K., Mukherjee, S., Ebert, B.L., Gillette, M.A., Paulovich, A., Mesirov, J.P., Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles (2005) Proceedings of the National Academy of Sciences of the United States of America, 102, pp. 15545-15550Sung, S.S., Bjorndahl, J.M., Wang, C.Y., Kao, H.T., Fu, S.M., Production of tumor necrosis factor/cachectin by human T cell lines and peripheral blood T lymphocytes stimulated by phorbol myristate acetate and anti-CD3 antibody (1988) The Journal of Experimental Medicine, 167, pp. 937-953Uzan, B., Poglio, S., Gerby, B., Wu, C.-L., Gross, J., Armstrong, F., Calvo, J., Pflumio, F., Interleukin-18 produced by bone marrow-derived stromal cells supports T-cell acute leukaemia progression (2014) EMBO Molecular Medicine, 6, pp. 821-834Van Vlierberghe, P., Ferrando, A., The molecular basis of T cell acute lymphoblastic leukemia (2012) The Journal of Clinical Investigation, 122, pp. 3398-3406Waibel, M., Solomon, V.S., Knight, D.A., Ralli, R.A., Kim, S.-K., Banks, K.-M., Vidacs, E., Johnstone, R.W., Combined targeting of JAK2 and Bcl-2/Bcl-xL to cure mutant JAK2-driven malignancies and overcome acquired resistance to JAK2 inhibitors (2013) Cell Reports, 5, pp. 1047-1059Ware, C.F., Network communications: lymphotoxins, LIGHT, and TNF (2005) Annual Review of Immunology, 23, pp. 787-819Ware, C.F., Crowe, P.D., Grayson, M.H., Androlewicz, M.J., Browning, J.L., Expression of surface lymphotoxin and tumor necrosis factor on activated T, B, and natural killer cells (1992) Journal of Immunology, 149, pp. 3881-3888Winter, S.S., Sweatman, J.J., Lawrence, M.B., Rhoades, T.H., Hart, A.L., Larson, R.S., Enhanced T-lineage acute lymphoblastic leukaemia cell survival on bone marrow stroma requires involvement of LFA-1 and ICAM-1 (2001) British Journal of Haematology, 115, pp. 862-871Wolf, S.S., Cohen, A., Expression of cytokines and their receptors by human thymocytes and thymic stromal cells (1992) Immunology, 77, pp. 362-368Wolf, M.J., Seleznik, G.M., Zeller, N., Heikenwalder, M., The unexpected role of lymphotoxin beta receptor signaling in carcinogenesis: from lymphoid tissue formation to liver and prostate cancer development (2010) Oncogene, 29, pp. 5006-5018Yin, C., Ye, J., Zou, J., Lu, T., Du, Y., Liu, Z., Fan, R., Ji, C., Role of stromal cells-mediated Notch-1 in the invasion of T-ALL cells (2015) Experimental Cell Research, 332, pp. 39-46