Circulating Biomarkers in Patients With Locally Advanced or Metastatic Renal Cell Carcinoma Treated With Everolimus in the Pre-nephrectomy Setting.

Many drugs are available in renal cell carcinoma (RCC), yet clinicians are still looking for predictive biomarkers of disease recurrence or progression supporting more personalised treatments. An assessment of circulating biomarkers over time was carried out in this French, open-label, single-arm, multicentre trial conducted in 25 patients with either locally advanced (n = 14) or metastatic RCC (n = 11) who received everolimus (10 mg daily) for 6 weeks prior to nephrectomy (NEORAD, NCT01715935). Circulating biomarkers, including circulating tumour cells, haematopoietic and endothelial cells, plasma angiogenesis and inflammatory markers were quantified at baseline, upon everolimus and post-nephrectomy. We assessed tumour burden, objective response rate upon RECIST1.1, disease-free survival (DFS) and progression-free survival (PFS). The correlation between circulating biomarkers was evaluated with multiple factor analysis and biomarker association with DFS/PFS by Cox regression. No objective response rate was obtained before nephrectomy. Upon everolimus, neutrophils, platelets and sVEGFR2 significantly decreased. We did not find any association between circulating biomarkers and DFS/PFS, but patients with the highest tumour burden at baseline had significantly higher plasma levels of interleukin-6, an inflammatory circulating biomarker, and lower levels of sVEGFR2, related to angiogenesis. Further understanding of the link between these circulating biomarkers could help to optimise drug combinations in RCC.

Therapeutic effect of fucoidan-stimulated endothelial colony-forming cells in peripheral ischemia.

BACKGROUND: Fucoidan, an antithrombotic polysaccharide, can induce endothelial colony-forming cells (ECFC) to adopt an angiogenic phenotype in vitro. OBJECTIVES: We evaluated the effect of fucoidan on vasculogenesis induced by ECFC in vivo. METHODS: We used a murine hindlimb ischemia model to probe the synergic role of fucoidan-treatment and ECFC infusion during tissue repair. RESULTS: We found that exposure of ECFC to fucoidan prior to their intravenous injection improved residual muscle blood flow and increased collateral vessel formation. Necrosis of ischemic tissue was significantly reduced on day 14, to 12.1% of the gastronecmius cross-sectional surface area compared with 40.1% in animals injected with untreated-ECFC. ECFC stimulation with fucoidan caused a rapid increase in cell adhesion to activated endothelium in flow conditions, and enhanced transendothelial extravasation. Fucoidan-stimulated ECFC were resistant to shear stresses of up to 21 dyn cm(-2). Direct binding assays showed strong interaction of fucoidan with displaceable binding sites on the ECFC membrane. Bolus intramuscular administration of fucoidan 1 day after surgery reduces rhabdomyolysis. Mice injected with fucoidan (15 mg kg(-1)) had significantly lower mean serum creatine phosphokinase (CPK) activity than control animals. This CPK reduction was correlated with muscle preservation against necrosis (P < 0.001). CONCLUSIONS: Fucoidan greatly increases ECFC-mediated angiogenesis in vivo. Its angiogenic effect would be due in part to its transportation to the ischemic site and its release after displacement by proteoglycans present in the extracellular matrix. The use of ECFC and fucoidan together, will be an efficient angiogenesis strategy to provide therapeutic neovascularization.

Osteoprotegerin, a new actor in vasculogenesis, stimulates endothelial colony-forming cells properties.

BACKGROUND: Osteoprotegerin (OPG), a soluble receptor of the tumour necrosis factor family, and its ligand, the receptor activator of nuclear factor-κB ligand (RANKL), are emerging as important regulators of vascular pathophysiology. OBJECTIVES: We evaluated their effects on vasculogenesis induced by endothelial colony-forming cells (ECFC) and on neovessel formation in vivo. METHODS: Effects of OPG and RANKL on in vitro angiogenesis were evaluated after ECFC incubation with OPG or RANKL (0-50 ng mL(-1)). Effects on microvessel formation were evaluated with an in vivo murin Matrigel plug assay. Vascularization was evaluated by measuring plug hemoglobin and vascular endothelial growth factor (VEGF)-R2 content 14 days after implantation. RESULTS: We found that ECFC expressed OPG and RANK but not RANKL mRNA. Treatment of ECFC with VEGF or stromal cell-derived factor-1 (SDF-1) upregulated OPG mRNA expression. OPG stimulated ECFC migration (P < 0.05), chemotaxis (P < 0.05) and vascular cord formation on Matrigel(®) (P < 0.01). These effects were correlated with SDF-1 mRNA overexpression, which was 30-fold higher after 4 h of OPG stimulation (P < 0.01). OPG-mediated angiogenesis involved the MAPK signaling pathway as well as Akt or mTOR cascades. RANKL also showed pro-vasculogenic effects in vitro. OPG combined with FGF-2 promoted neovessel formation in vivo, whereas RANKL had no effect. CONCLUSIONS: OPG induces ECFC activation and is a positive regulator of microvessel formation in vivo. Our results suggest that the OPG/RANK/RANKL axis may be involved in vasculogenesis and strongly support a modulatory role in tissue revascularization.

Magnetic control of vascular network formation with magnetically labeled endothelial progenitor cells.

We describe the applications of new cellular magnetic labeling method to endothelial progenitor cells (EPC), which have therapeutic potential for revascularization. Via their negative surface charges, anionic magnetic nanoparticles adsorb non-specifically to the EPC plasma membrane, thereby triggering efficient spontaneous endocytosis. The label is non-toxic and does not affect the cells' proliferative capacity. The expression of major membrane proteins involved in neovascularisation is preserved. Labeled cells continue to differentiate in vitro and to form tubular structures in Matrigel (an in vitro model of neovascularization). This process was followed in situ by using high-resolution MRI. Finally, we show that magnetic forces can be used to move magnetically labeled EPC in vitro and to modify their organization in Matrigel both in vitro an in vivo. Magnetic cell targeting opens up new possibilities for vascular tissue engineering and for delivering localized cell-based therapies.

Neoangiogenesis induced by progenitor endothelial cells: effect of fucoidan from marine algae.

Fucoidans--sulphated polysaccharides extracted from brown algae--could be beneficial in patients with ischemic diseases. Their antithrombotic and proangiogenic properties promote in animals, neovascularization and angiogenesis which prevent necrosis of ischemic tissue. In 1997, endothelial progenitor cells were first identified in human peripheral blood. They are recruited from bone marrow and contribute to neovascularization after ischemic injury. Mobilization of these cells in ischemic sites is an important step in new vessel formation. It is thought that the progenitors interact with endothelial cells, then extravasate and reach ischemic sites, where they proliferate and differentiate into new blood vessels. Although chemokines, cytokines and adhesion molecules are thought to be involved, the precise mechanism of progenitor mobilization is not fully understood. Recent studies suggest that stromal-derived factor 1 plays a critical role at several steps of progenitor mobilization. Given the role of proteoglycans within bone marrow, at the endothelium surface, and in growth factor and chemokine binding, fucoidans might influence the mobilization of endothelial progenitor cells and their incorporation in ischemic tissue. This review provides an update on circulating endothelial progenitors and their role in neovascularization. It focuses on recent advances in our understanding of interactions between these progenitor cells and exogenous sulphated polysaccharides, and their implications for understanding the fucoidan mechanism of action.