title: Damaged DNA binding protein 2 plays a role in breast cancer cell growth.
abstract: The Damaged DNA binding protein 2 (DDB2), is involved in nucleotide excision repair as well as in other biological processes in normal cells, including transcription and cell cycle regulation. Loss of DDB2 function may be related to tumor susceptibility. However, hypothesis of this study was that DDB2 could play a role in breast cancer cell growth, resulting in its well known interaction with the proliferative marker E2F1 in breast neoplasia. DDB2 gene was overexpressed in estrogen receptor (ER)-positive (MCF-7 and T47D), but not in ER-negative breast cancer (MDA-MB231 and SKBR3) or normal mammary epithelial cell lines. In addition, DDB2 expression was significantly (3.0-fold) higher in ER-positive than in ER-negative tumor samples (P = 0.0208) from 16 patients with breast carcinoma. Knockdown of DDB2 by small interfering RNA in MCF-7 cells caused a decrease in cancer cell growth and colony formation. Inversely, introduction of the DDB2 gene into MDA-MB231 cells stimulated growth and colony formation. Cell cycle distribution and 5 Bromodeoxyuridine incorporation by flow cytometry analysis showed that the growth-inhibiting effect of DDB2 knockdown was the consequence of a delayed G1/S transition and a slowed progression through the S phase of MCF-7 cells. These results were supported by a strong decrease in the expression of S phase markers (Proliferating Cell Nuclear Antigen, cyclin E and dihydrofolate reductase). These findings demonstrate for the first time that DDB2 can play a role as oncogene and may become a promising candidate as a predictive marker in breast cancer.
authors.affiliation: Laboratoire de Biologie Cellulaire du Développement, EA 3446 Université Henri Poincaré-Nancy Université, Vandoeuvre-lès-Nancy, France.
authors.forename: Zilal
authors.initials: Z
authors.lastname: Kattan
authors.forename: Sophie
authors.initials: S
authors.lastname: Marchal
authors.forename: Emilie
authors.initials: E
authors.lastname: Brunner
authors.forename: Carole
authors.initials: C
authors.lastname: Ramacci
authors.forename: Agnès
authors.initials: A
authors.lastname: Leroux
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Merlin
authors.forename: Lionel
authors.initials: L
authors.lastname: Domenjoud
authors.forename: Michel
authors.initials: M
authors.lastname: Dauça
authors.forename: Philippe
authors.initials: P
authors.lastname: Becuwe
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D005260:Female; D016193:G1 Phase; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D014411:Neoplastic Stem Cells / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D016196:S Phase
chemical_list: C117669:DDB2 protein, human; D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D011960:Receptors, Estrogen