Translation of Pro-Angiogenic and Anti-Angiogenic Therapies into Clinical Use

Combination of Astragali Polysaccharide and Curcumin Improves the Morphological Structure of Tumor Vessels and Induces Tumor Vascular Normalization to Inhibit the Growth of Hepatocellular Carcinoma

Normalizing the disordered tumor vasculature, rather than blocking it, is a novel method for anticancer therapy. Astragali polysaccharide (APS) and curcumin were reported to be active against carcinomas. However, the effect and mechanism of the combination of APS and curcumin on vascular normalization in hepatocellular carcinoma (HCC) was not clear. In the present study, effects of combined APS and curcumin on tumor vascular normalization were evaluated in HepG2 tumor-bearing mice. Photoacoustic tomography (PAT) was performed to observe the morphological structure of tumor vessels in vivo. The microstructure of the tumor vessels was also analyzed through scanning electron microscopy. Additionally, the expression of CD31 and NG2 was analyzed by immunohistochemical staining. Tumor vessels of HepG2 tumor-bearing mice treated with the combination were sparse with uniform growth, morphology rules, and complete vascular walls, which had fewer branches and sprouts. ECs of tumor vessels were arranged regularly and were tightly connected, tending toward normalization. The expression of CD31 was reduced while NG2 was increased significantly by the combination of APS and curcumin. The results indicated that APS and curcumin in combination showed a better effect on inhibiting tumor growth in an orthotopic nude-mouse model of HCC. More important, the combination induced normalization of tumor vascular better than APS or curcumin administration alone, improving the morphological structure of tumor vessels and promoting maturation of tumor vessels. The results of the present study provided a reasonable possibility for combination therapy of APS and curcumin in the treatment of HCC via tumor vascular normalization.

Celecoxib Nanoparticles for Therapeutic Angiogenesis

Controllable induction of blood vessel formation (angiogenesis) presents an important therapeutic goal in ischemic diseases and is also beneficial in various normal physiological processes. In this study, we have shown that nanoparticles of celecoxib, a lipophilic nonsteroidal anti-inflammatory drug, effectively evoke therapeutic angiogenesis in animal models, in both normal and ischemic organs. Celecoxib is widely considered to inhibit angiogenesis, although a recent study suggests that it can instead promote blood vessel growth in cancer cell lines. The hydrophobic nature of this drug necessitates its administration in nanoparticulate form in order to elicit a perceivable pharmacological response. We developed a facile method for nanoparticle formation by solvent extraction from microemulsions in supercritical carbon dioxide. This method exploits a spontaneous formation of nanometric domains within the microemulsion system and their rapid conversion to nanoparticles by supercritical fluid. The resultant nanoparticles were administered subcutaneously to mice in a biocompatible hydrogel, and caused a 4-fold increase in blood vessel count in normally perfused skin compared with drug-free particles. They were at least as effective in inducing angiogenesis as nanoparticles of deferoxamine, a well-established neovascularization promoter. Next, we evaluated their effect on ischemic tissues in murine model of myocardial infarction. We found that celecoxib nanoparticles were able to induce a significant vascularization of ischemic myocardium and hamper the progression of heart failure, which points toward a new approach for treating ischemia.