Decreased poly(ADP-ribosyl)ation of CTCF, a transcription factor, is associated with breast cancer phenotype and cell proliferation.
OBJECTIVE
There is compelling evidence of a relationship between poly(ADP-ribosyl)ation and tumorigenesis; however, much less is known about the role of specific targets of poly(ADP-ribosyl)ation in tumor development. Two forms of the multifunctional transcription factor, CTCF, were previously identified: a 130-kDa protein (CTCF-130), characteristic for cell lines, and a 180-kDa protein (CTCF-180), modified by poly(ADP-ribosyl)ation. This study was aimed to investigate differential poly(ADP-ribosyl)ation of CTCF in normal and tumor breast tissues.


METHODS
Western blot analysis, mass spectrometry, and immunohistochemical and immunofluorescent stainings were used to characterize CTCF-130 and CTCF-180 in breast cell lines, primary cultures, and normal and tumor breast tissues. The immunoreactivity score was used for CTCF-130 quantification in tissues.


RESULTS
We discovered that only CTCF-180 is detected in the normal breast tissues, whereas both CTCF-130 and CTCF-180 are present in breast tumors. Using an antibody specific for CTCF-130, we observed that 87.7% of breast tumors were positive for CTCF-130. A negative correlation existed between the levels of CTCF-130, tumor stage, and tumor size. Significantly, a transition from CTCF-180 to CTCF-130 was discovered in primary cultures generated from normal breast tissues, indicating a link between CTCF-130 and proliferation. Conversely, the appearance of CTCF-180 was observed following growth arrest in breast cell lines.


CONCLUSIONS
Collectively, our data suggest that the loss of CTCF poly(ADP-ribosyl)ation is associated with cell proliferation and breast tumor development. We propose the use of CTCF-130 as a marker for tumor breast cells and lower levels of CTCF-130 as an indicator of unfavorable prognosis.
Docquier
France
F
Department of Biological Sciences, University of Essex, Essex, United Kingdom.
Kita
Georgia-Xanthi
GX
Farrar
Dawn
D
Jat
Parmjit
P
O'Hare
Michael
M
Chernukhin
Igor
I
Gretton
Svetlana
S
Mandal
Adhip
A
Alldridge
Louise
L
Klenova
Elena
E
D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D000076246:CCCTC-Binding Factor; D049109:Cell Proliferation; D006801:Humans; D010641:Phenotype; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; D012097:Repressor Proteins; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases