Combined Effects of Cytokine TRAIL-Based DR5-Specific Fusion Protein with Olaparib on Tumor Cell Lines with Different BRCA Mutation Status

Objective: Tumor cell death induction via activation of TRAIL (tumor necrosis factor-related apoptosis inducing ligand) cytokine signaling pathway is a promising strategy for anticancer therapy. Previously, we developed a fusion protein SRH-DR5-B-iRGD based on the DR5 (death receptor 5)-specific cytokine TRAIL variant DR5-B with antiangiogenic peptides. The SRH peptide specifically binds to the VEGFR2 (vascular endothelial growth factor receptor 2) receptor and blocks its VEGF-mediated activation; the iRGD peptide binds to integrin αvβ3 and the NRP-1 (neuropilin-1) receptor. All of these targets are known to be overexpressed on the surface of tumor cells. In the current study, we investigated the cytotoxic activity of the SRH-DR5-B-iRGD fusion protein in comparison with DR5-B in vitro in ovarian and breast adenocarcinoma cell lines with different BRCA mutation status in combination with olaparib, a targeted poly(ADP-ribose) polymerase (PARP) inhibitor. Methods: Target receptor expression and correlation analysis were performed using the online tool TNMplot. Recombinant proteins DR5-B and SRH-DR5-B-iRGD were obtained in Escherichia coli. Cell viability was studied by MTT assay. Results and Discussion: Olaparib synergistically enhanced cytotoxicity of TRAIL-based proteins regardless of the cells’ BRCA mutation status. Importantly, this effect was more pronounced for SRH-DR5-B-iRGD. Conclusions: The combination of SRH-DR5-B-iRGD with olaparib can be considered as a new approach for the treatment of ovarian and breast adenocarcinoma regardless of their BRCA mutation status.