Journal article
Expression of the RET Proto-oncogene Is Regulated by TFAP2C in Breast Cancer Independent of the Estrogen Receptor
Annals of surgical oncology, Vol.20(7), pp.2204-2212
08/10/2012
DOI: 10.1245/s10434-012-2570-5
PMCID: PMC3697477
PMID: 22878616
Abstract
Background
The
RET
proto-oncogene is expressed as part of the estrogen receptor (ER) cluster in breast cancer. We sought to determine if TFAP2C regulates Ret expression directly or indirectly through ER.
Methods
Chromatin immunoprecipitation sequencing (ChIP-Seq) and gel-shift assay were used to identify TFAP2C binding sites in the
RET
promoter in four breast cancer cell lines. Ret mRNA and protein levels were evaluated in ER-positive and ER-negative breast cancer cell lines after knockdown of TFAP2C. Luciferase expression assay was performed to assess expression from two of the identified sites.
Results
ChIP-Seq identified five main binding peaks for TFAP2C in the
RET
promoter at −101.5 kb, −50.7 kb, −32.5 kb, +5.0 kb, and +33.6 from the
RET
transcriptional start site. Binding at three of the AP-2 sites was conserved across all four cell lines, whereas the
RET
−101.5 and
RET
+33.6 sites were each found to be unbound by TFAP2C in one cell line. A TFAP2C consensus element was confirmed for all five sites. Knockdown of TFAP2C by siRNA in ER-positive MCF-7 cells resulted in significant down regulation of Ret mRNA compared to nontargeting (NT) siRNA (0.09 vs. 1.0,
P
< 0.001). Knockdown of TFAP2C in ER-negative MDA-MB-453 cells also led to a significant reduction in Ret mRNA compared to NT siRNA (0.16 vs. 1.0,
P
< 0.001). In MCF-7 cells, knockdown of TFAP2C abrogated Ret protein expression (0.02 vs. 1.0,
P
< 0.001) before reduction in ER.
Conclusions
TFAP2C regulates expression of the
RET
proto-oncogene through five AP-2 regulatory sites in the
RET
promoter. Regulation of Ret by TFAP2C occurs independently of ER expression in breast carcinoma.
Details
- Title: Subtitle
- Expression of the RET Proto-oncogene Is Regulated by TFAP2C in Breast Cancer Independent of the Estrogen Receptor
- Creators
- Philip M Spanheimer - University of IowaGeorge W Woodfield - Department of Surgery, University of IowaAnthony R Cyr - Department of Surgery, University of IowaMikhail V Kulak - University of IowaLola S White-Baer - Department of Surgery, University of IowaThomas B Bair - University of IowaRonald J Weigel - Department of Surgery, University of Iowa
- Resource Type
- Journal article
- Publication Details
- Annals of surgical oncology, Vol.20(7), pp.2204-2212
- DOI
- 10.1245/s10434-012-2570-5
- PMID
- 22878616
- PMCID
- PMC3697477
- NLM abbreviation
- Ann Surg Oncol
- ISSN
- 1068-9265
- eISSN
- 1534-4681
- Publisher
- Springer-Verlag
- Language
- English
- Date published
- 08/10/2012
- Academic Unit
- Molecular Physiology and Biophysics; Anatomy and Cell Biology; Surgery; Biochemistry and Molecular Biology
- Record Identifier
- 9984284353502771
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