Cannabidiol inhibits angiogenesis by multiple mechanisms

SUMMARY. Background and purpose: Several studies demonstrated anti-proliferative and pro-apoptotic actions of cannabinoids on several tumours, together with their anti-angiogenic properties. The non-psychoactive cannabinoid cannabidiol (CBD) effectively inhibits in vitro and in vivo the growth of different types of tumours and down-regulates some pro-angiogenic signal produced by glioma cells. As its anti-angiogenic properties have not been thoroughly investigated to date, and given its very favorable pharmacological and toxicological profile, here we evaluated CBD ability to modulate tumour angiogenesis. Experimental approach: We firstly evaluated CBD effect on human umbilical vein endothelial cell (HUVEC) proliferation and viability– through MTT assay and FACS analysis-and in vitro motility-both in a classical Boyden chamber test and in a wound-healing assay. We next investigated CBD effects on different angiogenesis-related proteins released by HUVECs, using an angiogenic Array Kit and an enzyme-linked immunosorbent assay (ELISA) directed at MMP2. Afterwards we evaluated in vitro angiogenesis in treated HUVECs invading a Matrigel layer and in HUVEC spheroids embedded into collagen gels. We further characterized CBD effects using a Matrigel sponge model of in vivo angiogenesis. Key results: CBD induced HUVEC cytostasis without inducing apoptosis, inhibited HUVEC migration, invasion, and sprouting in vitro, and angiogenesis in vivo in matrigel sponges. These effects were associated with down-modulation of several angiogenesis-related molecules. Conclusions and Implications: This study reveals that CBD inhibits angiogenesis by multiple mechanisms. Its dual effect on both tumour and endothelial cells reinforces the hypothesis that CBD could represent a potential effective agent in cancer therapy.