RESUMO
BACKGROUND: ß-lapachone (ß-lap), the NQO1 bioactivatable drug, is thought to be a promising anticancer agent. However, the toxic side effects of ß-lap limit the drug use, highlighting the need for a thorough understanding of ß-lap's mechanism of action. ß-lap undergoes NQO1-dependent futile redox cycling, generating massive ROS and oxidative DNA lesions, leading to cell death. Thus, base excision repair (BER) pathway is an important resistance factor. XRCC1, a scaffolding component, plays a critical role in BER. METHODS: We knocked down XRCC1 expression by using pLVX-shXRCC1 in the MiaPaCa2 cells and BxPC3 cells and evaluated ß-lap-induced DNA lesions by γH2AX foci formation and alkaline comet assay. The cell death induced by XRCC1 knockdown + ß-lap treatment was analysed by relative survival, flow cytometry and Western blotting analysis. RESULTS: We found that knockdown of XRCC1 significantly increased ß-lap-induced DNA double-strand breaks, comet tail lengths and cell death in PDA cells. Furthermore, we observed combining XRCC1 knockdown with ß-lap treatment switched programmed necrosis with ß-lap monotherapy to caspase-dependent apoptosis. CONCLUSIONS: These results indicate that XRCC1 is involved in the repair of ß-lap-induced DNA damage, and XRCC1 loss amplifies sensitivity to ß-lap, suggesting targeting key components in BER pathways may have the potential to expand use and efficacy of ß-lap for gene-based therapy.
Assuntos
Antineoplásicos/farmacologia , Apoptose , Quebras de DNA de Cadeia Dupla , Naftoquinonas/farmacologia , Neoplasias Pancreáticas/terapia , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/deficiência , Antineoplásicos/efeitos adversos , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/terapia , Linhagem Celular Tumoral , Sobrevivência Celular , Ensaio Cometa , Reparo do DNA , DNA de Neoplasias/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular , Histonas/metabolismo , Humanos , Pontos de Checagem da Fase M do Ciclo Celular , NAD(P)H Desidrogenase (Quinona)/metabolismo , Naftoquinonas/efeitos adversos , Naftoquinonas/metabolismo , Necroptose/efeitos dos fármacos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Poli(ADP-Ribose) Polimerase-1/biossíntese , Pontos de Checagem da Fase S do Ciclo CelularRESUMO
PARP1 inhibitor (Niraparib, Olaparib, Rucaparib) maintenance therapy improves progression-free survival in platinum sensitive sporadic epithelial ovarian cancers. However, biomarkers of response to PARPi therapy is yet to be clearly defined. XRCC1, a scaffolding protein, interacts with PARP1 during BER and SSBR. In a large clinical cohort of 525 sporadic ovarian cancers, high XRCC1 or high PARP1 protein levels was not only associated with aggressive phenotypes but was also significantly linked with poor progression-free survival (pâ¯=â¯0.048 & pâ¯=â¯0.001 respectively) and poor ovarian cancer-specific survival (pâ¯=â¯0.020 & pâ¯=â¯0.008 respectively). Pre-clinically, Olaparib and Talazoparib therapy were selectively toxic in XRCC1 deficient or knock-out platinum sensitive ovarian cancer cells in 2D and 3D models. Increased sensitivity was associated with DNA double-strand break accumulation, cell cycle arrest and apoptotic cell accumulation. We conclude that XRCC1 deficiency predicts sensitivity to PARP inhibitor therapy. PARP1 targeting is a promising new approach in XRCC1 deficient ovarian cancers.