Angiotensin‐(1‐7) attenuates metastatic prostate cancer and reduces osteoclastogenesis1. Issue 1 (29th May 2012) - Krishnan, Bhavani
Abstract BACKGROUND Angiotensin‐(1‐7) [Ang‐(1‐7)] is an endogenous, heptapeptide hormone with anti‐proliferative and anti‐angiogenic properties. The primary objective of this study was to determine whether Ang‐(1‐7) effectively reduces prostate cancer metastasis in mice. METHODS Human PC3 prostate cancer cells were injected into the aortic arch via the carotid artery of SCID mice pre‐treated with Ang‐(1‐7) or injected into the tibia of athymic mice, administered Ang‐(1‐7) for 5 weeks beginning 2 weeks post‐injection. Tumor growth and volume were determined by bioluminescent and magnetic resonance imaging. The presence of tumors was confirmed by hematoxylin and eosin staining; TRAP histochemistry was used to identify osteolytic lesions. The effect of Ang‐(1‐7) on osteoclastogenesis was assessed in differentiated bone marrow cells. RESULTS Pre‐treatment with Ang‐(1‐7) prevented metastatic tumor formation following intra‐aortic injection of PC3 cells, while 83% of untreated mice developed tumors in metastatic sites. Circulating VEGF was significantly higher in control mice compared to mice administered Ang‐(1‐7). A 5‐week regimen of the heptapeptide hormone attenuated intra‐tibial tumor growth; Ang‐(1‐7) was significantly higher in the tibia of treated mice than in control animals. Osteoclastogenesis was reduced by 50% in bone marrow cells differentiated in the presence of Ang‐(1‐7), suggesting that the heptapeptide hormone prevents the formation of osteolytic lesions to reduce tumor survival in the bone microenvironment. CONCLUSIONS These findings suggest that Ang‐(1‐7) may serve as an anti‐angiogenic and anti‐metastatic agent for advanced prostate cancer. By extension, the heptapeptide hormone may provide effective therapy for bone metastasis produced from primary tumors of the lung and breast. Prostate 73: 71–82, 2013. © 2012 Wiley Periodicals, Inc.