title: Shp2E76K mutant confers cytokine-independent survival of TF-1 myeloid cells by up-regulating Bcl-XL.
abstract: Shp2 has been known to mediate growth factor-stimulated cell proliferation, but its role in cell survival is less clear. Gain-of-function Shp2 mutants such as Shp2E76K are associated with myeloid leukemias. We found that Shp2E76K could transform cytokine-dependent human TF-1 myeloid cells into cytokine independence and further characterized the Shp2E76K-induced cell survival mechanism in this study. Expression of Shp2E76K suppressed the cytokine withdrawal-induced intrinsic/mitochondrial apoptosis pathway, which is controlled by the Bcl-2 family proteins. Analysis of Bcl-2 family proteins showed that Bcl-XL and Mcl-1 were up-regulated in Shp2E76K-transformed TF-1 (TF-1/Shp2E76K) cells. Knockdown of Bcl-XL but not Mcl-1 with short hairpin RNAs prevented Shp2E76K-induced cytokine-independent survival. Roscovitine, which down-regulated Mcl-1, also did not prevent cytokine-independent survival of TF-1/Shp2E76K cells, whereas the Bcl-XL inhibitor HA14-1 did. Ras and mitogen-activated protein kinases Erk1 and Erk2 (Erk1/2) were constitutively activated in TF-1/Shp2E76K cells, whereas little active Akt was detected under cytokine-free conditions. Shp2E76K-induced Bcl-XL expression was suppressed by Mek inhibitors and by a dominant-negative Mek1 mutant but not by the phosphoinositide 3-phosphate inhibitor LY294002 and the Akt inhibitor API-2. Inhibition of Erk1/2 blocked cytokine-independent survival of TF-1/Shp2E76K cells, whereas inhibition of Akt had a minimal effect on cytokine-independent survival of TF-1/Shp2E76K cells. These results show that Shp2E76K can evoke constitutive Erk1/2 activation in TF-1 cells. Furthermore, Shp2E76K induces cytokine-independent survival of TF-1 cells by a novel mechanism involving up-regulation of Bcl-XL through the Erk1/2 pathway.
authors.affiliation: Molecular Oncology Program, H. Lee Moffitt Cancer Center and Research Institute, Department of Interdisciplinary Oncology, University of South Florida, Tampa 33612, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ren
authors.forename: Zhengming
authors.initials: Z
authors.lastname: Chen
authors.forename: Liwei
authors.initials: L
authors.lastname: Chen
authors.forename: Nicholas T
authors.initials: NT
authors.lastname: Woods
authors.forename: Gary W
authors.initials: GW
authors.lastname: Reuther
authors.forename: Jin Q
authors.initials: JQ
authors.lastname: Cheng
authors.forename: Hong-gang
authors.initials: HG
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
mesh_terms: D019943:Amino Acid Substitution; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D001578:Benzopyrans / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002747:Chlorpropamide / Q000031:analogs & derivatives / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D053492:Elafin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007377:Interleukin-3 / Q000378:metabolism* / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000201:enzymology / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000235:genetics; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D020125:Mutation, Missense; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D023461:Myeloid Progenitor Cells / Q000201:enzymology*; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009570:Nitriles / Q000494:pharmacology; D015689:Oncogene Protein p21(ras) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D011687:Purines / Q000494:pharmacology; D000077546:Roscovitine; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D051020:bcl-X Protein / Q000096:biosynthesis* / Q000235:genetics; D000096926:Benzenesulfonamides
chemical_list: D001578:Benzopyrans; D002747:Chlorpropamide; D002867:Chromones; D053492:Elafin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D007377:Interleukin-3; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D009025:Morpholines; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D009570:Nitriles; D015689:Oncogene Protein p21(ras); D047428:Protein Kinase Inhibitors; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2; D011687:Purines; D000077546:Roscovitine; D051020:bcl-X Protein; C111224:API 2; D000096926:Benzenesulfonamides; C494811:BCL2L1 protein, human; C508596:IL3 protein, human; C506806:PI3 protein, human; C456800:ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one