Manipulating the angiotensin system - new approaches to the treatment of solid tumours

Angiotensin 11 (Ang 11), a main effector peptide in the renin-angiotensin system (RAS), plays a fundamental role as a vasoconstrictor in controlling cardiovascular function and renal homeostasis. Ang 11 also acts as a growth promoter or angiogenic factor via type 1 angiotensin 11 receptors (AT(1)Rs) in certain tumour cell lines. Recent studies have shown the activation of the local RAS in various tumour tissues, including the abundant generation of Ang 11 by angiotensin-converting enzyme (ACE) and the upregulation of AT(1)R expression. Thus, considerable attention has been paid to the role of the RAS in cancer and its blockade as a new approach to the treatment of cancer. There is increasing evidence that the Ang II-AT(1)R system is involved in tumour growth, angiogenesis and metastasis in experimental models, suggesting the therapeutic potential of an ACE inhibitor and AT(1)R blocker, both of which have been used as anti hypertensive drugs. In addition, specific Ang II-degrading enzymes are expressed in tumours and play a regulatory role in cell proliferation and invasion. This review focuses on the role of the Ang II-AT(1)R system in solid tumours, particularly in the progression of gynaecological cancer, and presents the clinical potential of manipulating the angiotensin system as a novel and promising strategy for cancer treatment.