Blood Vessels Can Contribute To Tumor Suppression

A study from the Institute of Pharmacology and Structural Biology in Toulouse (France) has introduced a novel concept in cancer biology : Blood vessels in human tumors are not all the same and some types of blood vessels found in the tumor microenvironment (i. e. HEVs) can contribute to tumor suppression rather than tumor growth(Cancer Res 2011).

 A better understanding of HEVs at the molecular level, which is one of the major objectives of the research team, may have an important impact for cancer therapy.

Dendritic cells, which are well known for their role as antigen-presenting cells, play an unexpected and important role in the maintenance of HEV blood vessels in lymph nodes (Nature 2011). In addition, the scientists discovered the frequent presence of HEVs in human solid tumors, and their association with cytotoxic lymphocyte infiltration and favourable clinical outcome in breast cancer. They also showed that IL-33 is a chromatin-associated cytokine (PNAS 2007, 453 citations) that function as an alarm signal (alarmin) released upon cellular damage (PNAS 2009, 312 citations). Inflammatory proteases can generate truncated forms of IL-33 that are 30-fold more potent than the full length protein for activation of group 2 innate lymphoid cells (PNAS 2012, 133 citations, PNAS 2014).

An important objective  is now to further characterize IL-33 regulation and mechanisms of action in vivo, through the use of multidisciplinary approaches.