| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2145703 | Molecular Oncology | 2013 | 15 Pages |
Cancer cells may use PARP enzymes and Homologous Recombination to repair single and double strand breaks caused by genotoxic insults. In this study, the PARP-1 inhibitor Rucaparib was utilized to increase the sensitivity to chemoradiotherapy treatment in BRCA-2-deficient and -proficient pancreatic cancer cells. We used the pancreatic cancer cell lines, Capan-1 with mutated BRCA-2 and Panc-1, AsPC-1 and MiaPaCa-2 with BRCA-1/2 wild type. Cells were treated with Rucaparib and/or radiotherapy (4–10 Gy) plus Gemcitabine then the capability to proliferate was evaluated by colony formation, cell counting and MTT assays. Flow cytometry, immunocytochemistry and western blotting were utilized to assess cell response to Rucaparib plus irradiation. The antitumour effectiveness of combining the PARP-1 inhibitor before, together and after radiotherapy evidenced the first as the optimal schedule in blocking cell growth. Pre-exposure to Rucaparib increased the cytotoxicity of Gemcitabine plus radiotherapy by heavily inducing the accumulation of cells in G2/M phase, impairing mitosis and finally inducing apoptosis and authophagy. The upregulation of p-Akt and downregulation of p53 were evidenced in MiaPaCa-2 which displayed replication stress features. For the first time, the rationale of using a PARP inhibitor as chemoradiosensitizer in pancreatic cancer models has been hypothesized and demonstrated.
► Pre-exposure to Rucaparib increased the cytotoxicity of radiotherapy plus Gemcitabine in pancreatic cancer models. ► The formation of γH2AX foci after Rucaparib plus irradiation was evaluated to assess the DNA damage. ► The formation of RAD51 foci after Rucaparib plus irradiation was evaluated to assess the HR system functionality. ► The cell response to Rucaparib plus irradiation suggested the occurrence of different cell death mechanisms. ► Akt-1 activation plus p53 repression increase irradiation-dependent cytotoxicity probably through mitotic catastrophe.
