Platelet-specific ablation of PDGFB impairs vascular function and pericyte recruitment in tumors and promotes metastasis

• Platelet-derived growth factor B (PDGFB) plays a crucial role in recuitment of PDGF-receptor b positive pericytes to blood vessels and the endothelium is an essential source of PDGFB in this process. PDGFB was originally isolated from platelets, which consitute a major reservoir of this growth factor. Under physiological conditions, platelets are not activated unless there is a wound, which then leads to rapid activation and degranulation of the platelet content. However, in the tumor microenvironment platelets are continuously activated, exposing tumors to the plethora of growth factors contained in platelet granules. In the current study we address the role of platelet-derived PDGFB in vascular function and pericyte recruitment in tumors by creating a platelet-specific knock-out of PDGFB. We find that mice with PDGFB-deficient platelets are viable and fertile. Furthermore, vascular function and pericyte recruitment to healthy vessels were unaffected by the lack of PDGFB in platelets. In contrast, tumor vascular function, as well as pericyte coverage, is significantly impaired in mice with PDGFB-deficient platelets. Moreover, lack of PDGFB in platelets leads to enhanced spontaneous liver metastasis in a model for pancreatic neuroendocrine carcinoma, further indicating that platelet-derived PDGFB contributes to maintain vascular integrity in the tumor microenvironment where extensive vascular remodeling is ongoing. With this finding we identify a previously unknown role for platelet-derived PDGFB.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Keyword

Platelet

pericyte

PDGFB

vascular function

metastasis

Publication and Content Type

vet (subject category)

ovr (subject category)