TY - JOUR
T1 - KIT signaling regulates MITF expression through miRNAs in normal and malignant mast cell proliferation
AU - Lee, Youl Nam
AU - Brandal, Stephanie
AU - Noel, Pierre
AU - Wentzel, Erik
AU - Mendell, Joshua T.
AU - McDevitt, Michael A.
AU - Kapur, Reuben
AU - Carter, Melody
AU - Metcalfe, Dean D.
AU - Takemoto, Clifford M.
PY - 2011/3/31
Y1 - 2011/3/31
N2 - Activating mutations in codon D816 of the tyrosine kinase receptor, KIT, are found in the majority of patients with systemic mastocytosis. We found that the transcription factor, microphthalmia-associated transcription factor (MITF), is highly expressed in bone marrow biopsies from 9 of 10 patients with systemic mastocytosis and activating c-KIT mutations. In primary and transformed mast cells, we show that KIT signaling markedly up-regulates MITF protein. We demonstrate that MITF is required for the proliferative phenotype by inhibiting colony-forming units with sh-RNA knockdown of MITF. Furthermore, constitutively active KIT does not restore growth of primary MITF-deficient mast cells. MITF mRNA levels do not change significantly with KIT signaling, suggesting posttranscriptional regulation. An array screen from mast cells identified candidate miRNAs regulated by KIT signaling. We found that miR-539 and miR-381 are downregulated by KIT signaling and they repressed MITF expression through conserved miRNA binding sites in the MITF 3′-untranslated region. Forced expression of these miRNAs suppressed MITF protein and inhibited colony-forming capacity of mastocytosis cell lines. This work demonstrates a novel regulatory pathway between 2 critical mast cell factors, KIT and MITF, mediated by miRNAs; dysregulation of this pathway may contribute to abnormal mast cell proliferation and malignant mast cell diseases.
AB - Activating mutations in codon D816 of the tyrosine kinase receptor, KIT, are found in the majority of patients with systemic mastocytosis. We found that the transcription factor, microphthalmia-associated transcription factor (MITF), is highly expressed in bone marrow biopsies from 9 of 10 patients with systemic mastocytosis and activating c-KIT mutations. In primary and transformed mast cells, we show that KIT signaling markedly up-regulates MITF protein. We demonstrate that MITF is required for the proliferative phenotype by inhibiting colony-forming units with sh-RNA knockdown of MITF. Furthermore, constitutively active KIT does not restore growth of primary MITF-deficient mast cells. MITF mRNA levels do not change significantly with KIT signaling, suggesting posttranscriptional regulation. An array screen from mast cells identified candidate miRNAs regulated by KIT signaling. We found that miR-539 and miR-381 are downregulated by KIT signaling and they repressed MITF expression through conserved miRNA binding sites in the MITF 3′-untranslated region. Forced expression of these miRNAs suppressed MITF protein and inhibited colony-forming capacity of mastocytosis cell lines. This work demonstrates a novel regulatory pathway between 2 critical mast cell factors, KIT and MITF, mediated by miRNAs; dysregulation of this pathway may contribute to abnormal mast cell proliferation and malignant mast cell diseases.
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UR - http://www.scopus.com/inward/citedby.url?scp=79953721454&partnerID=8YFLogxK
U2 - 10.1182/blood-2010-07-293548
DO - 10.1182/blood-2010-07-293548
M3 - Article
C2 - 21273305
AN - SCOPUS:79953721454
SN - 0006-4971
VL - 117
SP - 3629
EP - 3640
JO - Blood
JF - Blood
IS - 13
ER -