Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and the role of SYK in its pathogenesis is not completely understood. Using tissue microarray, we demonstrated for the first time that SYK protein is activated in 27 of 61 (44%) primary human DLBCL tissues. Among DLBCL cell lines, 7 were sensitive and 3 were resistant to a highly specific SYK inhibitor, PRT060318. In sensitive DLBCL cells, SYK inhibition blocked the G(1)-S transition and caused cell-cycle arrest. This effect was reproduced by genetic reduction of SYK using siRNA. A detailed analysis of the BCR signaling pathways revealed that the consequence of SYK inhibition on PLCγ2 and AKT, as opposed to ERK1/2, was responsible for cell-cycle arrest. Genetic knock-down of these key molecules decelerated the proliferation of lymphoma cells. In addition, BCR signaling can be blocked by PRT060318 in primary lymphoma cells. Together, these findings provide insights into cellular pathways required for lymphoma cell growth and support the rationale for considering SYK inhibition as a potentially useful therapy for DLBCL. The results further suggest the possibility of using PLCγ2 and AKT as biomarkers to predict therapeutic response in prospective clinical trials of specific SYK inhibitors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antineoplastic Agents / pharmacology*
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Biomarkers / metabolism
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Cell Line, Tumor
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Drug Resistance, Neoplasm*
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G1 Phase / drug effects
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Gene Expression Regulation, Neoplastic
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Humans
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Intracellular Signaling Peptides and Proteins / antagonists & inhibitors*
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Lymph Nodes / drug effects
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Lymph Nodes / metabolism
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Lymph Nodes / pathology
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Lymphoma, Large B-Cell, Diffuse / drug therapy*
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Lymphoma, Large B-Cell, Diffuse / metabolism
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Lymphoma, Large B-Cell, Diffuse / pathology
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Molecular Targeted Therapy
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Neoplasm Proteins / antagonists & inhibitors*
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism
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Phospholipase C gamma / antagonists & inhibitors
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Phospholipase C gamma / genetics
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Phospholipase C gamma / metabolism
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Phosphorylation / drug effects
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Protein Kinase Inhibitors / pharmacology*
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Protein Processing, Post-Translational / drug effects
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Protein-Tyrosine Kinases / antagonists & inhibitors*
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism
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Proto-Oncogene Proteins c-akt / antagonists & inhibitors
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Proto-Oncogene Proteins c-akt / genetics
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Proto-Oncogene Proteins c-akt / metabolism
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RNA Interference
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RNA, Messenger / metabolism
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RNA, Small Interfering
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Signal Transduction / drug effects
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Syk Kinase
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Tumor Cells, Cultured
Substances
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Antineoplastic Agents
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Biomarkers
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Intracellular Signaling Peptides and Proteins
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Neoplasm Proteins
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Protein Kinase Inhibitors
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RNA, Messenger
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RNA, Small Interfering
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Protein-Tyrosine Kinases
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SYK protein, human
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Syk Kinase
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Proto-Oncogene Proteins c-akt
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Phospholipase C gamma