| Abstract: |
UNLABELLED: The ETS family of transcription factors has been repeatedly implicated in tumorigenesis. In prostate cancer, ETS family members, such as ERG, ETV1, ETV4, and ETV5, are frequently overexpressed due to chromosomal translocations, but the molecular mechanisms by which they promote prostate tumorigenesis remain largely undefined. Here, we show that ETS family members, such as ERG and ETV1, directly repress the expression of the checkpoint kinase 1 (CHK1), a key DNA damage response cell-cycle regulator essential for the maintenance of genome integrity. Critically, we find that ERG expression correlates with CHK1 downregulation in human patients and demonstrate that Chk1 heterozygosity promotes the progression of high-grade prostatic intraepithelial neoplasia into prostatic invasive carcinoma in Pten(+) (/-) mice. Importantly, CHK1 downregulation sensitizes prostate tumor cells to etoposide but not to docetaxel treatment. Thus, we identify CHK1 as a key functional target of the ETS proto-oncogenic family with important therapeutic implications. SIGNIFICANCE: Genetic translocation and aberrant expression of ETS family members is a common event in different types of human tumors. Here, we show that through the transcriptional repression of CHK1, ETS factors may favor DNA damage accumulation and consequent genetic instability in proliferating cells. Importantly, our findings provide a rationale for testing DNA replication inhibitor agents in ETS-positive TP53-proficient tumors. ©2015 American Association for Cancer Research. |
| Keywords: |
dna binding protein; promoter region; genetics; dna-binding proteins; disease course; mouse; animal; metabolism; animals; mice; mice, knockout; dna damage; protein kinases; etoposide; protein binding; down-regulation; genotype; transcription factor; genetic transcription; transcription, genetic; drug resistance; pathology; drug resistance, neoplasm; cell line, tumor; protein p53; transcription factors; cell transformation, neoplastic; prostatic neoplasms; gene expression regulation; gene expression regulation, neoplastic; conserved sequence; cell transformation; promoter regions, genetic; disease progression; transactivator protein; prostate tumor; tumor cell line; phosphatidylinositol 3,4,5 trisphosphate 3 phosphatase; pten phosphohydrolase; tumor suppressor protein p53; binding site; down regulation; binding sites; trans-activators; checkpoint kinase 1; protein kinase; pten protein, human; knockout mouse; transcription factor ets; proto-oncogene proteins c-ets; etv1 protein, human; humans; human; male; erg protein, human
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