Basal c-Jun NH2-terminal protein kinase activity is essential for survival and proliferation of T-cell acute lymphoblastic leukemia cells.
Hyperactivation of c-Jun NH2-terminal protein kinase (JNK) has been found in various malignant lymphocytes and inhibition of JNK activity leads to cell cycle arrest and apoptosis. However, the role of JNK activity in the oncogenic growth of T-cell acute lymphoblastic leukemia (T-ALL) cells remains largely unknown. Here, we report that treatment of T-ALL cells with JNK inhibitors led to cell cycle arrest and apoptosis and increased sensitivity to Fas-mediated apoptosis, whereas weak ectopic expression of MKK7-JNK1 fusion protein, which shows constitutive JNK activity, in T-ALL cells resulted in accelerated cell cycle progression and resistance to Fas-mediated apoptosis. The protein levels of c-Myc and Bcl-2 were reduced in the presence of JNK inhibitors but were enhanced with MKK7-JNK1. Small interfering RNA against JNK1, but not JNK2, exhibited similar effects to JNK inhibitors. These findings suggest that targeting JNK, especially JNK1 isoform, may have some important therapeutic implications in the treatment of T-ALL. Further exploration revealed that JNK protein and basal JNK activity in T-ALL cells showed aberrant subcellular localization, but no hyperactivation of JNK was observed. Thus, our work suggests that there might be novel mechanism(s) other than hyperactivation underlying the protumorigenic role of JNK activity.
Cui
Jian
J
Department of Molecular Immunology, Institute of Basic Medical Sciences, 27 Taiping Road, Beijing 100850, People's Republic of China.
Wang
Qingyang
Q
Wang
Jing
J
Lv
Ming
M
Zhu
Ning
N
Li
Yan
Y
Feng
Jiannan
J
Shen
Beifen
B
Zhang
Jiyan
J
D000097:Acetonitriles / Q000494:pharmacology; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D052160:Benzothiazoles / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019169:Jurkat Cells; D048688:MAP Kinase Kinase 7 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D048055:Mitogen-Activated Protein Kinase 8 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048056:Mitogen-Activated Protein Kinase 9 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D034622:RNA Interference; D014162:Transfection
C489138:1,3-benzothiazol-2-yl(2-((2-(3-pyridinyl)ethyl)amino)-4-pyrimidinyl)acetonitrile; D000097:Acetonitriles; D000873:Anthracenes; D052160:Benzothiazoles; C489427:MYC protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; C432165:pyrazolanthrone; D048056:Mitogen-Activated Protein Kinase 9; D048031:JNK Mitogen-Activated Protein Kinases; D048055:Mitogen-Activated Protein Kinase 8; D048688:MAP Kinase Kinase 7; C482569:MAP2K7 protein, human