The role of angiotensin-(1-7) on acquired platinum resistance-induced angiogenesis in non-small cell lung cancer in vitro and in vivo.

Renin-angiotensin system (RAS) signaling has been implicated in the development of cancer. The new RAS ACE2/Ang-(1-7)/Mas axis antagonizes the classical ACE/Ang II/AT1R axis. Ang-(1-7) has pleiotropic roles in lung cancer including suppressing proliferation, angiogenesis, and metastasis. This research was designed to investigate the effect of Ang-(1-7) on tumor-associated angiogenesis in DDP-resistant lung cancer cell lines. We first established acquired DDP-resistant cell lines A549 (A549-DDP) and LLC (LLC-DDP). We next performed RT-qPCR, western blot, ELISA, tube formation, microvessel density detection, immunohistochemistry, and tumor formation assays. The results showed that the mRNA and protein levels of RAS components and vascular endothelial growth factor A (VEGFa) were lessened in the A549/LLC-DDP+Ang-(1-7) group compared with the A549/LLC-DDP group. This effect could be blocked by the MAS receptor antagonist A779. The data revealed that Ang-(1-7) could perform its antiangiogenic function by PI3K/AKT and MAPK pathways. Furthermore, the impact of Ang-(1-7) on tumor-associated angiogenesis has been confirmed in lung cancer xenograft model with acquired DDP resistance. These results provide a theoretical basis for designing therapeutic strategies for targeting Ang-(1-7) in the treatment of NSCLC.