title: Clinical significance of miR-144-ZFX axis in disseminated tumour cells in bone marrow in gastric cancer cases.
abstract: BACKGROUND
  We previously reported that bone marrow (BM) was a homing site for gastric cancer (GC) cells leading to haematogenous metastases. There has been little study that microRNAs regulated pathways in malignant cells or host cells in BM, and thereby regulated the progression of GC.
  
  
  METHODS
  Both microRNA microarray and gene expression microarray analyses of total RNA from BM were conducted, comparing five early and five advanced GC patients. We focused on miR-144-ZFX axis as a candidate BM regulator of GC progression and validated the origin of the microRNA expression in diverse cell fractions (EpCAM(+)CD45(-), EpCAM(-)CD45(+), and CD14(+)) by magnetic-activated cell sorting (MACS).
  
  
  RESULTS
  Quantitative reverse-transcriptase (RT)-PCR analysis validated diminished miR-144 expression in stage IV GC patients with respect to stage I GC patients (t-test, P=0.02), with an inverse correlation to ZFX (ANOVA, P<0.01). Luciferase reporter assays in five GC cell lines indicated their direct binding and validated by western blotting. Pre-miR144 treatment and the resultant repression of ZFX in GC cell lines moderately upregulated their susceptibility to 5-fluorouracil chemotherapy. In MACS-purified BM fractions, the level of miR-144 expression was significantly diminished in disseminated tumour cell fraction (P=0.0005). Diminished miR-144 expression in 93 cases of primary GC indicated poor prognosis.
  
  
  CONCLUSIONS
  We speculate that disseminated cancer cells could survive in BM when low expression of miR-144 permits upregulation of ZFX. The regulation of the miR-144-ZFX axis in cancer cells has a key role in the indicator of the progression of GC cases.
authors.affiliation: Department of Surgery, Kyushu University Beppu Hospital, Tsurumihara, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Akiyoshi
authors.forename: T
authors.initials: T
authors.lastname: Fukagawa
authors.forename: H
authors.initials: H
authors.lastname: Ueo
authors.forename: M
authors.initials: M
authors.lastname: Ishibashi
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Fabbri
authors.forename: M
authors.initials: M
authors.lastname: Sasako
authors.forename: Y
authors.initials: Y
authors.lastname: Maehara
authors.forename: K
authors.initials: K
authors.lastname: Mimori
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D001853:Bone Marrow / Q000378:metabolism* / Q000473:pathology; D018450:Disease Progression; D020869:Gene Expression Profiling; D006801:Humans; D053208:Kaplan-Meier Estimate; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D009360:Neoplastic Cells, Circulating; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D051741:Kruppel-Like Transcription Factors; C554293:MIRN144 microRNA, human; D035683:MicroRNAs; C062076:zinc finger protein, X-linked