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Mastocytosis associated with a rare germline KIT K509I mutation displays a well-differentiated mast cell phenotype.

ABSTRACT: Mastocytosis associated with germline KIT activating mutations is exceedingly rare. We report the unique clinicopathologic features of a patient with systemic mastocytosis caused by a de novo germline KIT K509I mutation.We sought to investigate the effect of the germline KIT K509I mutation on human mast cell development and function.Primary human mast cells derived from CD34(+) peripheral blood progenitors were examined for growth, development, survival, and IgE-mediated activation. In addition, a mast cell transduction system that stably expressed the KIT K509I mutation was established.KIT K509I biopsied mast cells were round, CD25(-), and well differentiated. KIT K509I progenitors cultured in stem cell factor (SCF) demonstrated a 10-fold expansion compared with progenitors from healthy subjects and developed into mature hypergranular mast cells with enhanced antigen-mediated degranulation. KIT K509I progenitors cultured in the absence of SCF survived but lacked expansion and developed into hypogranular mast cells. A KIT K509I mast cell transduction system revealed SCF-independent survival to be reliant on the preferential splicing of KIT at the adjacent exonic junction.Germline KIT mutations associated with mastocytosis drive a well-differentiated mast cell phenotype distinct to that of somatic KIT D816V disease, the oncogenic potential of which might be influenced by SCF and selective KIT splicing.

SUBMITTER: Chan EC

PROVIDER: S-EPMC4125511 | biostudies-other | 2014 Jul

REPOSITORIES: biostudies-other

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Mastocytosis associated with a rare germline KIT K509I mutation displays a well-differentiated mast cell phenotype.

Chan Eunice Ching EC Bai Yun Y Kirshenbaum Arnold S AS Fischer Elizabeth R ER Simakova Olga O Bandara Geethani G Scott Linda M LM Wisch Laura B LB Cantave Daly D Carter Melody C MC Lewis John C JC Noel Pierre P Maric Irina I Gilfillan Alasdair M AM Metcalfe Dean D DD Wilson Todd M TM

The Journal of allergy and clinical immunology 20140228 1

<h4>Background</h4>Mastocytosis associated with germline KIT activating mutations is exceedingly rare. We report the unique clinicopathologic features of a patient with systemic mastocytosis caused by a de novo germline KIT K509I mutation.<h4>Objectives</h4>We sought to investigate the effect of the germline KIT K509I mutation on human mast cell development and function.<h4>Methods</h4>Primary human mast cells derived from CD34(+) peripheral blood progenitors were examined for growth, developmen ...[more]

PMID: 24582309

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Project description:The HMC-1.2 human mast cell (huMC) line is often employed in the study of attributes of neoplastic huMCs as found in patients with mastocytosis and their sensitivity to interventional drugs in vitro and in vivo. HMC-1.2 cells express constitutively active KIT, an essential growth factor receptor for huMC survival and function, due to the presence of two oncogenic mutations (D816V and V560G). However, systemic mastocytosis is commonly associated with a single D816V-KIT mutation. The functional consequences of the coexisting KIT mutations in HMC-1.2 cells are unknown. We used CRISPR/Cas9-engineering to reverse the V560G mutation in HMC-1.2 cells, resulting in a subline (HMC-1.3) with a single mono-allelic D816V-KIT variant. Transcriptome analyses predicted reduced activity in pathways involved in survival, cell-to-cell adhesion, and neoplasia in HMC-1.3 compared to HMC-1.2 cells, with differences in expression of molecular components and cell surface markers. Consistently, subcutaneous inoculation of HMC-1.3 into mice produced significantly smaller tumors than HMC-1.2 cells, and in colony assays, HMC-1.3 formed less numerous and smaller colonies than HMC-1.2 cells. However, in liquid culture conditions, the growth of HMC-1.2 and HMC-1.3 cells was comparable. Phosphorylation levels of ERK1/2, AKT and STAT5, representing pathways associated with constitutive oncogenic KIT signaling, were also similar between HMC-1.2 and HMC-1.3 cells. Despite these similarities in liquid culture, survival of HMC-1.3 cells was diminished in response to various pharmacological inhibitors, including tyrosine kinase inhibitors used clinically for treatment of advanced systemic mastocytosis, and JAK2 and BCL2 inhibitors, making HMC-1.3 more susceptible to these drugs than HMC-1.2 cells. Our study thus reveals that the additional V560G-KIT oncogenic variant in HMC-1.2 cells modifies transcriptional programs induced by D816V-KIT, confers a survival advantage, alters sensitivity to interventional drugs, and increases the tumorigenicity, suggesting that engineered huMCs with a single D816V-KIT variant may represent an improved preclinical model for mastocytosis.

Dataset Information

Mastocytosis associated with a rare germline KIT K509I mutation displays a well-differentiated mast cell phenotype.

Publications

Mastocytosis associated with a rare germline KIT K509I mutation displays a well-differentiated mast cell phenotype.

Similar Datasets

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