Vascular Disruption Therapy as a New Strategy for Cancer Treatment.

A functional blood vessel network is required to deliver oxygen and nutrients to the cancer cells for their growth. Angiogenesis, the formation of new blood vessels from pre-existing ones, is one of the major mechanisms to create this vascular network. Anti-angiogenic therapy was conceived as the inhibition of the cellular and molecular players involved in tumor angiogenesis such as vascular endothelial growth factor and its main receptors. Due to limitations of this therapy, different approaches of vessel modulation such as vascular normalization or vascular promotion have been studied showing benefits in different tumor models and clinical trials. In contrast to anti-angiogenic therapy, which inhibits the blood vessels that are being formed, vascular disruption therapy aims to destroy already formed tumor vessels. These malignant vascular structures differ from other blood vessels in terms of endothelial cell states, pericyte coverage and basement membrane development. The molecules used for vascular disruption are microtubule-binding molecules, flavonoids that induce endothelial cell apoptosis or molecules vectorized to endothelial receptors. Many vascular disruption agents have been tested in clinical trials showing some promising results, but with some limitations that include resistant rim cells or the development of hypoxia that induces cancer regrowth and poor delivery of the anti-tumor agents. The main objective of this review is to focus on vascular disruption agents therapy, novel molecules, new ways to overcome therapy resistance to them, current clinical status and, especially, the upcoming challenges and applications of these molecules.