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Functional and phenotypic studies of two variants of a human mast cell line with a distinct set of mutations in the c‐kit proto‐oncogene
Author(s) -
Sundström Magnus,
Vliagoftis Harissios,
Karlberg Peter,
Butterfield Joseph H.,
Nilsson Kenneth,
Metcalfe Dean D.,
Nilsson Gunnar
Publication year - 2003
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.2003.01559.x
Subject(s) - biology , proto oncogene proteins c kit , receptor tyrosine kinase , mast cell , tyrosine kinase , stem cell factor , systemic mastocytosis , kinase , microbiology and biotechnology , protein kinase b , cell culture , cancer research , genetics , phosphorylation , signal transduction , progenitor cell , stem cell , immunology
Summary The human mast cell line (HMC)‐1 cell line is growth‐factor independent because of a constitutive activity of the receptor tyrosine kinase Kit. Such deregulated Kit activity has also been suggested causative in gastrointestinal stromal tumours (GISTs) and mastocytosis. HMC‐1 is the only established continuously growing human mast cell line and has therefore been widely employed for in vitro studies of human mast cell biology. In this paper we describe two sublines of HMC‐1, named HMC‐1 560 and HMC‐1 560,816 , with different phenotypes and designated by the locations of specific mutations in the c‐kit proto‐oncogene. Activating mutations in the Kit receptor were characterized using the pyrosequencing™ method. Both sublines have a heterozygous T to G mutation at codon 560 in the juxtamembrane region of the c‐kit gene causing an amino acid substitution of Gly‐560 for Val. In contrast, only HMC‐1 560,816 cells have the c‐kit V816 mutation found in mast cell neoplasms causing an Asp→Val substitution in the intracellular kinase domain. Kit was constitutively phosphorylated on tyrosine residues and associated with phosphatidylinositol 3′‐kinase (PI 3‐kinase) in both variants of HMC‐1, but this did not lead to a constitutive phosphorylation of Akt or extracellular regulated protein kinase (ERK), which are signalling molecules normally activated by the interaction of stem cell factor (SCF) with Kit. The documentation and characterization of two sublines of HMC‐1 cells provides both information on the biological consequences of mutations in Kit and recognition of the availability of what in reality are two distinct cultured human mast cell lines.