Role of oxidative stress in angiogenesis and the therapeutic potential of antioxidants in breast cancer.

The escalation of cancer cases globally, especially breast cancer, is of concern. Angiogenesis is hallmark of cancer pathogenesis and plays an important role in cancer progression and metastasis. Pro-angiogenic agents, secreted by tumor cells, form new blood vessels, and produce reactive oxygen species (ROS). ROS promote angiogenesis via two major pathways: namely Vascular Endothelial Growth Factor (VEGF) dependent and non-VEGF dependent pathways. As a consequence of unbalanced ROS overproduction and low antioxidants levels, oxidative stress occurs and promotes angiogenesis in breast cancer tissues. Thus, the potential use of antioxidants as a preventive therapy in breast cancer. Preclinical studies depict that vitamins A and E may counter oxidative stress resulting in reduction of metastasis and viability of breast cancer. Furthermore, clinical studies demonstrate a decline in breast cancer risk in postmenopausal women upon the consumption of antioxidants. Herein, we discuss various pro-angiogenic agents that may play an important role in breast cancer angiogenesis. Moreover, the contribution of oxidative stress in inducing the angiogenic process is extensively reviewed here. Furthermore, the findings of pre-clinical and clinical studies on the use of antioxidants, namely vitamins A and E, in breast cancer are deliberated upon, along with the role of angiogenesis in cancer therapy.