title: Gene expression patterns of hemizygous and heterozygous KIT mutations suggest distinct oncogenic pathways: a study in NIH3T3 cell lines and GIST samples.
abstract: OBJECTIVE
  Most gain of function mutations of tyrosine kinase receptors in human tumours are hemizygous. Gastrointestinal stromal tumours (GIST) with homozygous mutations have a worse prognosis. We aimed to identify genes differentially regulated by hemizygous and heterozygous KIT mutations.
  
  
  METHODS
  Expression of 94 genes and 384 miRNA was analysed with low density arrays in five NIH3T3 cell lines expressing the full-length human KIT cDNA wild-type (WT), hemizygous KIT mutation with del557-558 (D6) or del564-581 (D54) and heterozygous WT/D6 or WT/D54. Expression of 5 of these genes and 384 miRNA was then analysed in GISTs samples.
  
  
  RESULTS
  Unsupervised and supervised hierarchical clustering of the mRNA and miRNA profiles showed that heterozygous mutants clustered with KIT WT expressing cells while hemizygous mutants were distinct. Among hemizygous cells, D6 and D54 expressing cells clustered separately. Most deregulated genes have been reported as potentially implicated in cancer and severals, as ANXA8 and FBN1, are highlighted by both, mRNA and miRNA analyses. MiRNA and mRNA analyses in GISTs samples confirmed that their expressions varied according to the mutation of the alleles. Interestingly, RGS16, a membrane protein of the regulator of G protein family, correlate with the subcellular localization of KIT mutants and might be responsible for regulation of the PI3K/AKT signalling pathway.
  
  
  CONCLUSIONS
  Patterns of mRNA and miRNA expression in cells and tumours depend on heterozygous/hemizygous status of KIT mutations, and deletion/presence of TYR568 & TYR570 residues. Thus each mutation of KIT may drive specific oncogenic pathways.
authors.affiliation: EA4340 'Epidémiologie et Oncogénèse des tumeurs digestives', Faculté de médecine PIFO, UVSQ, Guyancourt, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Bachet
authors.forename: Séverine
authors.initials: S
authors.lastname: Tabone-Eglinger
authors.forename: Sophie
authors.initials: S
authors.lastname: Dessaux
authors.forename: Anthony
authors.initials: A
authors.lastname: Besse
authors.forename: Sabrina
authors.initials: S
authors.lastname: Brahimi-Adouane
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Emile
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Blay
authors.forename: Laurent
authors.initials: L
authors.lastname: Alberti
mesh_terms: D000483:Alleles; D000704:Analysis of Variance; D000818:Animals; D016000:Cluster Analysis; D005091:Exons / Q000235:genetics; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D057898:Hemizygote; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D041681:NIH 3T3 Cells; D020411:Oligonucleotide Array Sequence Analysis; D025341:Principal Component Analysis; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D019009:Proto-Oncogene Proteins c-kit