Profiling YB-1 target genes uncovers a new mechanism for MET receptor regulation in normal and malignant human mammary cells.
Basal-like breast cancers (BLBCs) are aggressive tumors with high relapse rates and poor survival. We recently reported that >70% of primary BLBCs express the oncogenic transcription/translation factor Y-box binding protein-1 (YB-1) and silencing it with small interfering RNAs (siRNAs) attenuates the growth of BLBC cell lines. To understand the basis of these earlier findings, we profiled YB-1:DNA complexes by chromatin immunoprecipitation (ChIP)-on-chip. Several tumor growth-promoting genes such as MET, CD44, CD49f, WNT and NOTCH family members were identified. In addition, YB-1 and MET are coordinately expressed in BLBC cell lines, as well as in normal human mammary progenitor cells. MET was confirmed to be a YB-1 target through traditional ChIP and gel-shift assays. More specifically, YB-1 binds to -1018 bp on the MET promoter. Silencing YB-1 with siRNA decreased MET promoter activity, transcripts, as well as protein levels and signaling. Conversely, expressing wild-type YB-1 or a constitutively active mutant YB-1 (D102) increased MET expression. Finally, silencing YB-1 or MET attenuated anchorage-independent growth of BLBC cell lines. Together, these findings implicate MET as a target of YB-1 that work in concert to promote BLBC growth.
Finkbeiner
M R
MR
Laboratory for Oncogenomic Research, Departments of Pediatrics and Experimental Medicine, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada.
Astanehe
A
A
To
K
K
Fotovati
A
A
Davies
A H
AH
Zhao
Y
Y
Jiang
H
H
Stratford
A L
AL
Shadeo
A
A
Boccaccio
C
C
Comoglio
P
P
Mertens
P R
PR
Eirew
P
P
Raouf
A
A
Eaves
C J
CJ
Dunn
S E
SE
D001940:Breast / Q000737:chemistry*; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology*; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D020869:Gene Expression Profiling; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D019859:Proto-Oncogene Proteins c-met; D034741:RNA, Small Interfering / Q000235:genetics; D017978:Receptors, Growth Factor / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells / Q000737:chemistry; D051840:Y-Box-Binding Protein 1
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D017978:Receptors, Growth Factor; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D017228:Hepatocyte Growth Factor; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met