Evaluation of Anti-Angiogenic Potential of Angiotensin Converting Enzyme Inhibitor in Animal Model of Mammary Gland Cancer and In Various in Vivo Angiogenesis Models

Abstract

Aim and objective: Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in females worldwide. Recent studies have shown that the rennin angiotensin system (RAS) via angiogenesis is involved in tumor development. The objective of our study is to investigate anti-angiogenic activity of ACE-I, perindopril in 12- dimethylbenz[a]anthracene (DMBA) induced breast cancer and to study anti-angiogenic effect of perindopril by in corneal micropocket, mouse xenograft model and chick yolk sac membrane. Materials and Methods: At 50 days postpartum, 32 female Sprague Dawley rats grouped into control, control treated with ACE inhibitor perindopril (2 mg/kg/day, p.o.), disease control, disease treated with ACE inhibitor perindopril (2 mg/kg/day). Breast cancer was induced by oral administration of 60 mg/kg dimethylbenz[a]anthracene (DMBA), a dose sufficient to cause 100% tumor incidence in the disease control group and disease treated group over the course of the study. Animals were palpated twice a week starting five weeks after DMBA administration in order to record the presence, location, size, and date of detection for all tumors. For Corneal micropocket model, Balb/c mice were randomly divided into two groups: treatment and control group. Corneal micropocket model in mouse was used to dynamically observe angiogenesis under a stereoscopic zoom microscope and a digital camera system and to evaluate the effect of perindopril on angiogenesis. Balb/c mice were subcutaneously implanted with breast cancer tissues for tumor xenograft studies. In chick yolk sac membrane (YSM) model of angiogenesis, fertilized chick eggs (60 hours of incubation) were opened, and their contents were poured into beakers for 12 hourincubation and then the test solution was added into silicon rings laid on YSM for another 12-24 hours of incubation. The influences of perindopril on YSM angiogenesis were observed dynamically.Results: Administration of dimethylbenz[a]anthracene (DMBA) caused significant increase in cancer biochemical markers, like lactate dehydrogenase (LDH) and Gamma glutamyl transferase (GGT) Perindopril treatment (2 mg/kg/day, p.o) showed significant decrease in LDH and GGT levels as compared to disease control group. The treatment also showed significant decrease in MDA and significant increase in reduced glutathione and superoxide dismutase (SOD) level in breast homogenate as compared to disease control group. Treatment with perindopril also caused a significant decrease in inflammatory markers, like C-reactive protein and erythrocyte sedimentation rate and decreased hemoglobin levels as compared to disease control group. Histopathological evaluation showed hyperplastic and well demarcated tubular adenoma in tumor tissue, treatment with perindopril caused inhibition in the development of hyperplasia. In YSM model, The results showed that the YSM vascular growth was obviously inhibited by an angiogenesis inhibitor perindopril. In corneal micropocket model of angiogenesis, treatment with perindopril caused inhibition of neovascularisation as compared to control group. In mouse xenograft model, treatment with perindopril also caused reduction in tumor volume as compared to control group. Conclusion: From the present investigations, we can conclude that the perindopril inhibits the neovascularisation in tumor. Since perindopril is relatively safe that causes no severe side effects as compared to the available chemotherapeutic drugs and it is already in clinic as an antihypertensive drug. Metastatic breast cancer is usually associated with many cardiovascular complications, so the use of perindopril as a neo adjuvant or adjuvant therapy in patients with metastatic breast cancer associated with cardio vascular complications may be beneficial.