Abstract
The protein tyrosine phosphatase CD45, encoded by the PTPRC gene, is well known as a regulator of B- and T-cell receptor signaling. In addition, CD45 negatively regulates JAK family kinases downstream of cytokine receptors. Here, we report the presence of CD45 inactivating mutations in T-cell acute lymphoblastic leukemia. Loss-of-function mutations of CD45 were detected in combination with activating mutations in IL-7R, JAK1, or LCK, and down-regulation of CD45 expression caused increased signaling downstream of these oncoproteins. Furthermore, we demonstrate that down-regulation of CD45 expression sensitizes T cells to cytokine stimulation, as observed by increased JAK/STAT signaling, whereas overexpression of CD45 decreases cytokine-induced signaling. Taken together, our data identify a tumor suppressor role for CD45 in T-cell acute lymphoblastic leukemia.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cell Line, Tumor
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Cell Proliferation / drug effects
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Gene Expression Regulation, Leukemic / drug effects
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Genes, Tumor Suppressor / drug effects
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Genes, Tumor Suppressor / physiology
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HEK293 Cells
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Humans
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Janus Kinases / metabolism
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Leukocyte Common Antigens / antagonists & inhibitors
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Leukocyte Common Antigens / genetics*
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Leukocyte Common Antigens / metabolism
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Mutation* / physiology
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Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / genetics*
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Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / metabolism
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Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / pathology
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RNA, Small Interfering / pharmacology
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STAT Transcription Factors / metabolism
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Signal Transduction / drug effects
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Signal Transduction / genetics
Substances
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RNA, Small Interfering
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STAT Transcription Factors
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Janus Kinases
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Leukocyte Common Antigens