Janus kinases are critical components of signaling pathways that regulate hematopoiesis. Mutations of the non-receptor tyrosine kinase JAK2 are found in many BCR-ABL-negative myeloproliferative neoplasms. Preclinical results support that JAK2 inhibitors could show efficacy in treating chronic myeloproliferative neoplasms. JAK2 has also been postulated to play a role in BCR-ABL signal transduction. Therefore, inhibitors of JAK2 kinases are turning into therapeutic strategies for treatment of chronic myelogenous leukemia (CML). In this study, the effects of two novel JAK2 inhibitors, NVP-BSK805 and NVP-BVB808, have been investigated in cell lines expressing either BCR-ABL or mutant JAK2. Possible synergies between NVP-BSK805/NVP-BVB808 and the kinase inhibitors imatinib and nilotinib were assessed. Proliferation and apoptosis tests with both substances showed response in the following cell lines: CHRF-288-11, SET-2 and UKE-1. All BCR-ABL-positive cell lines showed some reduction in proliferation, but with half-maximal growth-inhibitory values >1 µM. Combination of the JAK2 inhibitors with imatinib and nilotinib showed no significant additive or synergistic effects, although all BCR-ABL-positive cell lines responded well to both CML therapeutic agents. Interestingly, it seemed that the combination of imatinib with NVP-BSK805 had a protective effect on the cells. Combination treatment with nilotinib did not show this effect.

Nowell PC, Hungerford DA: Chromosome studies on normal and leukemic human leukocytes. J Natl Cancer Inst 1960;25:85-109.
Ugo V, James C, Vainchenker W: A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera (in French). Med Sci (Paris) 2005;21:669-670.
Kralovics R, Passamonti F, Buser AS, Teo SS, Tiedt R, Passweg JR, Tichelli A, Cazzola M, Skoda RC: A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 2005;352:1779-1790.
Levine RL, Wadleigh M, Cools J, Ebert BL, Wernig G, Huntley BJ, Boggon TJ, Wlodarska I, Clark JJ, Moore S, Adelsperger J, Koo S, Lee JC, Gabriel S, Mercher T, D'Andrea A, Fröhling S, Döhner K, Marynen P, Vandenberghe P, Mesa RA, Tefferi A, Griffin JD, Eck MJ, Sellers WR, Meyerson M, Golub TR, Lee SJ, Gilliland DG: Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis. Cancer Cell 2005;7:387-397.
Baxter EJ, Scott LM, Campbell PJ, East C, Fourouclas N, Swanton S, Vassiliou GS, Bench AJ, Boyd EM, Curtin N, Scott MA, Erber WN, Green AR: Cancer Genome Project. Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders. Lancet 2005;365:1054-1061.
Argetsinger LS, Campbell GS, Yang X, Witthuhn BA, Silvennoinen O, Ihle JN, Carter-Su C: Identification of JAK2 as a growth hormone receptor-associated tyrosine kinase. Cell 1993;74:237-244.
Silvennoinen O, Witthuhn BA, Quelle FW, Cleveland JL, Yi T, Ihle JN: Structure of the murine Jak2 protein-tyrosine kinase and its role in interleukin 3 signal transduction. Proc Natl Acad Sci USA 1993;90:8429-8433.
Müller M, Briscoe J, Laxton C, Guschin D, Ziemiecki A, Silvenoinnen O, Harpur AG, Barbieri G, Witthuhn BA, Schindler C: The protein tyrosine kinase JAK1 complements defects in interferon-alpha/beta and -gamma signal transduction. Nature 1993;366:129-135.
Witthuhn BA, Quelle FW, Silvennoinen O, Yi T, Tang B, Miura O, Ihle JN: JAK2 associates with the erythropoietin receptor and is tyrosine phosphorylated and activated following stimulation with erythropoietin. Cell 1993;74:227-236.
O'Shea JJ, Gadina M, Schreiber RD: Cytokine signaling in 2002: new surprises in the Jak/Stat pathway. Cell Vol 2002;109:S121-S131.
Zhao R, Xing S, Li Z, Fu X, Li Q, Krantz SB, Zhao ZJ: Identification of an acquired JAK2 mutation in polycythemia vera. J Biol Chem 2005;280:22788-22792.
James C, Ugo V, Le Couédic JP, Staerk J, Delhommeau F, Lacout C, Garḉon L, Raslova H, Berger R, Bennaceur-Griscelli A, Villeval JL, Constantinescu SN, Casadevall N, Vainchenker W: A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. Nature 2005;434:1144-1148.
Lippert E, Boissinot M, Kralovics R, Girodon F, Dobo I, Praloran V, Boiret-Dupre N, Skoda RC, Hermouet S: The JAK2-V617F mutation is frequently present at diagnosis in patients with essential thrombocythemia and polycythemia vera. Blood 2006;108:1865-1867.
Stein BL, Crispino JD, Moliterno AR: Janus kinase inhibitors: an update on the progress and promise of targeted therapy in the myeloproliferative neoplasms. Curr Opin Oncol 2011;23:609-616.
Quintás-Cardama A, Kantarjian H, Cortes J, Verstovsek S: Janus kinase inhibitors for the treatment of myeloproliferative neoplasias and beyond. Nat Rev Drug Discov 2011;10:127-140.
Verstovsek S, Kantarjian H, Mesa RA, Pardanani AD, Cortes-Franco J, Thomas DA, Estrov Z, Fridman JS, Bradley EC, Erickson-Viitanen S, Vaddi K, Levy R, Tefferi A: Safety and efficacy of INCB018424, a JAK1 and JAK2 inhibitor, in myelofibrosis. N Engl J Med 2010;363:1117-1127.
Pardanani A, Gotlib JR, Jamieson C, Cortes JE, Talpaz M, Stone RM, Silverman MH, Gilliland DG, Shorr J, Tefferi A: Safety and efficacy of TG101348, a selective JAK2 inhibitor, in myelofibrosis. J Clin Oncol 2011;29:789-796.
Verstovsek S: Therapeutic potential of JAK2 inhibitors. Hematology Am Soc Hematol Educ Program 2009, pp 636-642.
Druker BJ, Guilhot F, O'Brien SG, Gathmann I, Kantarjian H, Gattermann N, Deininger MW, Silver RT, Goldman JM, Stone RM, Cervantes F, Hochhaus A, Powell BL, Gabrilove JL, Rousselot P, Reiffers J, Cornelissen JJ, Hughes T, Agis H, Fischer T, Verhoef G, Shepherd J, Saglio G, Gratwohl A, Nielsen JL, Radich JP, Simonsson B, Taylor K, Baccarani M, So C, Letvak L, Larson RA, IRIS Investigators. Five-year follow-up of patients receiving imatinib for chronic myeloid leukemia. N Engl J Med 2006;355:2408-2417.
Pendergast AM, Quilliam LA, Cripe LD, Bassing CH, Dai Z, Li N, Batzer A, Rabun KM, Der CJ, Schlessinger J: BCR-ABL-induced oncogenesis is mediated by direct interaction with the SH2 domain of the GRB-2 adaptor protein. Cell 1993;75:175-185.
Puil L, Liu J, Gish G, Mbamalu G, Bowtell D, Pelicci PG, Arlinghaus R, Pawson T: Bcr-Abl oncoproteins bind directly to activators of the Ras signalling pathway. EMBO J 1994;13:764-773.
Darnell JE, Kerr IM, Stark GR: Jak-STAT pathways and transcriptional activation in response to IFNs and other extracellular signaling proteins. Science 1994;264:1415-1421.
ten Hoeve J, Arlinghaus RB, Guo JQ, Heisterkamp N, Groffen J: Tyrosine phosphorylation of CRKL in Philadelphia + leukemia. Blood 1994;84:1731-1736.
Wilson-Rawls J, Xie S, Liu J, Laneuville P, Arlinghaus RB: P210 Bcr-Abl interacts with the interleukin 3 receptor beta(c) subunit and constitutively induces its tyrosine phosphorylation. Cancer Res 1996;56:3426-3430.
Ilaria RL, Van Etten RA: P210 and P190(BCR/ABL) induce the tyrosine phosphorylation and DNA binding activity of multiple specific STAT family members. J Biol Chem 1996;271:31704-31710.
Xie S, Wang Y, Liu J, Sun T, Wilson MB, Smithgall TE, Arlinghaus RB: Involvement of Jak2 tyrosine phosphorylation in Bcr-Abl transformation. Oncogene 2001;20:6188-6195.
Shuai K, Halpern J, ten Hoeve J, Rao X, Sawyers CL: Constitutive activation of STAT5 by the BCR-ABL oncogene in chronic myelogenous leukemia. Oncogene 1996;13:247-254.
Samanta AK, Chakraborty SN, Wang Y, Schlette E, Reddy EP, Arlinghaus RB: Destabilization of Bcr-Abl/Jak2 network by a Jak2/Abl kinase inhibitor ON044580 overcomes drug resistance in blast crisis chronic myelogenous leukemia (CML). Genes Cancer 2010;1:346-359.
Nelson EA, Walker SR, Weisberg E, Bar-Natan M, Barrett G, Gashin LB, Terrell S, Klitgaard JL, Santo L, Addorio MR, Ebert BL, Griffin JD, Frank DA: The STAT5 inhibitor pimozide decreases survival of chronic myelogenous leukemia cells resistant to kinase inhibitors. Blood 2011;117:3421-3429.
Warsch W, Kollmann K, Eckelhart E, Fajmann S, Cerny-Reiterer S, Hölbl A, Gleixner KV, Dworzak M, Mayerhofer M, Hoermann G, Herrmann H, Sillaber C, Egger G, Valent P, Moriggl R, Sexl V: High STAT5 levels mediate imatinib resistance and indicate disease progression in chronic myeloid leukemia. Blood 2011;117:3409-3420.
Baffert F, Régnier CH, De Pover A, Pissot-Soldermann C, Tavares GA, Blasco F, Brueggen J, Chéne P, Drueckes P, Erdmann D, Furet P, Gerspacher M, Lang M, Ledieu D, Nolan L, Ruetz S, Trappe J, Vangrevelinghe E, Wartmann M, Wyder L, Hofmann F, Radimerski T: Potent and selective inhibition of polycythemia by the quinoxaline JAK2 inhibitor NVP-BSK805. Mol Cancer Ther 2010;9:1945-1955.
Weigert O, Lane AA, Bird L, Kopp N, Chapuy B, van Bodegom D, Toms AV, Marubayashi S, Christie AL, McKeown M, Paranal RM, Bradner JE, Yoda A, Gaul C, Vangrevelinghe E, Romanet V, Murakami M, Tiedt R, Ebel N, Evrot E, De Pover A, Régnier CH, Erdmann D, Hofmann F, Eck MJ, Sallan SE, Levine RL, Kung AL, Baffert F, Radimerski T, Weinstock DM: Genetic resistance to JAK2 enzymatic inhibitors is overcome by HSP90 inhibition. J Exp Med 2012;209:259-273.
Mercher T, Wernig G, Moore SA, Levine RL, Gu TL, Fröhling S, Cullen D, Polakiewicz RD, Bernard OA, Boggon TJ, Lee BH, Gilliland DG: JAK2T875N is a novel activating mutation that results in myeloproliferative disease with features of megakaryoblastic leukemia in a murine bone marrow transplantation model. Blood 2006;108:2770-2779.
Quentmeier H, MacLeod RA, Zaborski M, Drexler HG: JAK2 V617F tyrosine kinase mutation in cell lines derived from myeloproliferative disorders. Leukemia 2006;20:471-476.
Samanta A, Perazzona B, Chakraborty S, Sun X, Modi H, Bhatia R, Priebe W, Arlinghaus R: Janus kinase 2 regulates Bcr-Abl signaling in chronic myeloid leukemia. Leukemia 2011;25:463-472.
Samanta AK, Lin H, Sun T, Kantarjian H, Arlinghaus RB: Janus kinase 2: a critical target in chronic myelogenous leukemia. Cancer Res 2006;66:6468-6472.
Andraos R, Qian Z, Bonenfant D, Rubert J, Vangrevelinghe E, Scheufler C, Marque F, Régnier CH, De Pover A, Ryckelynck H, Bhagwat N, Koppikar P, Goel A, Wyder L, Tavares G, Baffert F, Pissot-Soldermann C, Manley PW, Gaul C, Voshol H, Levine RL, Sellers WR, Hofmann F, Radimerski T: Modulation of activation-loop phosphorylation by JAK inhibitors is binding mode dependent. Cancer Discov 2012;2:512-523.
Radujkovic A, Fruehauf S, Zeller WJ, Ho AD, Topaly J: Synergistic activity of nilotinib and established chemotherapeutic drugs in imatinib-sensitive and -resistant BCR-ABL-positive cells. Cancer Chemother Pharmacol 2010;66:255-264.
Greene LM, Kelly L, Onnis V, Campiani G, Lawler M, Williams DC, Zisterer DM: STI-571 (imatinib mesylate) enhances the apoptotic efficacy of pyrrolo-1,5-benzoxazepine-6, a novel microtubule-targeting agent, in both STI-571-sensitive and -resistant Bcr-Abl-positive human chronic myeloid leukemia cells. J Pharmacol Exp Ther 2007;321:288-297.
O'Brien SG, Guilhot F, Larson RA, Gathmann I, Baccarani M, Cervantes F, Cornelissen JJ, Fischer T, Hochhaus A, Hughes T, Lechner K, Nielsen JL, Rousselot P, Reiffers J, Saglio G, Shepherd J, Simonsson B, Gratwohl A, Goldman JM, Kantarjian H, Taylor K, Verhoef G, Bolton AE, Capdeville R, Druker BJ, IRIS Investigators: Imatinib compared with interferon and low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukemia. N Engl J Med 2003;48:994-1004.
O'Hare T, Eide CA, Deininger MW: Bcr-Abl kinase domain mutations, drug resistance, and the road to a cure for chronic myeloid leukemia. Blood 2007;110:2242-2249.
Witte DP, Harris RE, Jenski LJ, Lampkin BC: Megakaryoblastic leukemia in an infant: establishment of a megakaryocytic tumor cell line in athymic nude mice. Cancer 1986;58:238-244.
Gorre ME, Mohammed M, Ellwood K, Hsu N, Paquette R, Rao PN, Sawyers CL: Clinical resistance to STI-571 cancer therapy caused by BCR-ABL gene mutation or amplification. Science 2001;293:876-880.
Grandage VL, Everington T, Linch DC, Khwaja A: Gö6976 is a potent inhibitor of the JAK 2 and FLT3 tyrosine kinases with significant activity in primary acute myeloid leukaemia cells. Br J Haematol 2006;135:303-316.
Hart S, Goh KC, Novotny-Diermayr V, Hu CY, Hentze H, Tan YC, Madan B, Amalini C, Loh YK, Ong LC, William AD, Lee A, Poulsen A, Jayaraman R, Ong KH, Ethirajulu K, Dymock BW, Wood JW: SB1518, a novel macrocyclic pyrimidine-based JAK2 inhibitor for the treatment of myeloid and lymphoid malignancies. Leukemia 2011;25:1751-1759.
Tao WJ, Lin H, Sun T, Samanta AK, Arlinghaus R: BCR-ABL oncogenic transformation of NIH 3T3 fibroblasts requires the IL-3 receptor. Oncogene 2008;27:3194-3200.
Klejman A, Schreiner SJ, Nieborowska-Skorska M, Slupianek A, Wilson M, Smithgall TE, Skorski T: The Src family kinase Hck couples BCR/ABL to STAT5 activation in myeloid leukemia cells. EMBO J 2002;21:5766-5774.
Zhang B, Li M, McDonald T, Holyoake TL, Moon RT, Campana D, Shultz L, Bhatia R: Microenvironmental protection of CML stem and progenitor cells from tyrosine kinase inhibitors through N-cadherin and Wnt-β-catenin signaling. Blood 2013;121:1824-1838.
Williams RT, Roussel MF, Sherr CJ: Arf gene loss enhances oncogenicity and limits imatinib response in mouse models of Bcr-Abl-induced acute lymphoblastic leukemia. Proc Natl Acad Sci USA 2006;103:6688-6693.
Holtz M, Forman SJ, Bhatia R: Growth factor stimulation reduces residual quiescent chronic myelogenous leukemia progenitors remaining after imatinib treatment. Cancer Res 2007;67:1113-1120.
Essers MA, Offner S, Blanco-Bose WE, Waibler Z, Kalinke U, Duchosal MA, Trumpp A: IFNalpha activates dormant haematopoietic stem cells in vivo. Nature 2009;458:904-908.
Glauche I, Horn K, Horn M, Thielecke L, Essers MA, Trumpp A, Roeder I: Therapy of chronic myeloid leukaemia can benefit from the activation of stem cells: simulation studies of different treatment combinations. Br J Cancer 2012;106:1742-1752.
Nair RR, Tolentino JH, Argilagos RF, Zhang L, Pinilla-Ibarz J, Hazlehurst LA: Potentiation of nilotinib-mediated cell death in the context of the bone marrow microenvironment requires a promiscuous JAK inhibitor in CML. Leuk Res 2012;36:756-763.
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