Estrogen Therapy Induces Receptor-Dependent DNA Damage Enhanced by PARP Inhibition in ER+ Breast Cancer.
Clin Cancer Res
; 29(18): 3717-3728, 2023 09 15.
Article
em En
| MEDLINE
| ID: mdl-37439680
ABSTRACT
PURPOSE:
Clinical evidence indicates that treatment with estrogens elicits anticancer effects in â¼30% of patients with advanced endocrine-resistant estrogen receptor α (ER)-positive breast cancer. Despite the proven efficacy of estrogen therapy, its mechanism of action is unclear and this treatment remains underused. Mechanistic understanding may offer strategies to enhance therapeutic efficacy. EXPERIMENTALDESIGN:
We performed genome-wide CRISPR/Cas9 screening and transcriptomic profiling in long-term estrogen-deprived ER+ breast cancer cells to identify pathways required for therapeutic response to the estrogen 17ß-estradiol (E2). We validated findings in cell lines, patient-derived xenografts (PDX), and patient samples, and developed a novel combination treatment through testing in cell lines and PDX models.RESULTS:
Cells treated with E2 exhibited replication-dependent markers of DNA damage and the DNA damage response prior to apoptosis. Such DNA damage was partially driven by the formation of DNARNA hybrids (R-loops). Pharmacologic suppression of the DNA damage response via PARP inhibition with olaparib enhanced E2-induced DNA damage. PARP inhibition synergized with E2 to suppress growth and prevent tumor recurrence in BRCA1/2-mutant and BRCA1/2-wild-type cell line and PDX models.CONCLUSIONS:
E2-induced ER activity drives DNA damage and growth inhibition in endocrine-resistant breast cancer cells. Inhibition of the DNA damage response using drugs such as PARP inhibitors can enhance therapeutic response to E2. These findings warrant clinical exploration of the combination of E2 with DNA damage response inhibitors in advanced ER+ breast cancer, and suggest that PARP inhibitors may synergize with therapeutics that exacerbate transcriptional stress.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Mama
Tipo de estudo:
Prognostic_studies
Limite:
Female
/
Humans
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article