Novel PARP Inhibitor DDPF-20 Induces DNA Damage and Inhibits Angiogenesis through the PI3K/Akt/VEGF Pathway

Background: Poly (ADP-ribose) polymerase (PARP) plays a key role in DNA damage repair. A novel compound (E)-N'-(2,3-dibromo-4,5-dihydroxyphenyl)-N-(phenylcarbamothioyl)formimidamide (DDPF-20) with excellent PARP inhibitory activity was synthesized. Objective: In this study, we aimed to clarify the mechanism of the novel PARP inhibitor DDPF-20 against lung cancer by inducing DNA damage and inhibiting angiogenesis. Methods: The cytotoxic effect of DDPF-20 on the A549 cell line was determined with an MTT assay. Cell cycle and apoptosis were determined by a flow cytometer. Moreover, the γH2AX foci were detected by immunofluorescence. Capillary-like tube formation assay and chick chorioallantoic membrane (CAM) assay were used to detect the angiogenesis inhibitory effect of DDPF-20. The expressions of related proteins were detected by western blot. The anticancer activity of DDPF-20 in vivo was also detected. Results: With an IC50 value of 52.42 ± 15.13 nM, DDPF-20 inhibited the proliferation, induced G2/M cycle arrest, and induced apoptosis of human lung cancer A549 cells. Further research showed that DDPF-20 induced DNA doublestrand breaks (DSBs). Interestingly, DDPF-20 inhibited the tube formation of HUVEC cells, as well as inhibited the neovascularization of CAM, proving the angiogenesis inhibitory ability of DDPF-20. Mechanism studies proved that DDPF-20 inhibited the PI3K/Akt/VEGF signaling pathway. In an in vivo study, DDPF-20 inhibited tumor growth of an A549 xenograft. Analysis of the molecular mechanism underlying this effect revealed that the PI3K/Akt/VEGF pathway was involved in DDPF-20-induced cell death and inhibited angiogenesis in vivo. Conclusion: This study suggested that the novel PARP inhibitor DDPF-20 may have therapeutic potential in treating lung cancer.