tannins and Fibrosarcoma

Tumor angiogenesis is a critical step for the growth and metastasis of solid tumors. Vascular endothelial growth factor (VEGF) is the most important angiogenic molecule associated with tumor-induced neovascularization. VEGF exerts its activity through binding to its receptor tyrosine kinase, KDR/Flk-1, expressed on the surface of endothelial cells. From the screening of medicinal plants, we have identified 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG) from the roots of Paeonia lactiflora that inhibited the binding of VEGF to KDR/Flk-1. PGG efficiently blocked VEGF-induced human umbilical vein endothelial cell proliferation and the growth of immortalized human microvascular endothelial cells, but did not affect the growth of HT1080 human fibrosarcoma and DU-145 human prostate carcinoma cells. PGG also blocked VEGF-induced capillary-like tube formation of endothelial cell on Matrigel. Our results suggest that PGG could be a candidate for developing anti-angiogenic agent.

Topics: Cell Division; Cell Movement; Collagen; Drug Combinations; Endothelium, Vascular; Fibrosarcoma; Humans; Hydrolyzable Tannins; Laminin; Male; Paeonia; Plant Extracts; Prostatic Neoplasms; Protein Binding; Proteoglycans; Receptors, Vascular Endothelial Growth Factor; Sodium-Potassium-Exchanging ATPase; Tannins; Umbilical Veins; Vascular Endothelial Growth Factor A

The antitumor effect of oenothein B, a macrocyclic ellagitannin from Oenothera erythrosepala Bordas, on rodent tumors was studied. Oenothein B exhibited a strong antitumor activity against MM2 ascites tumors upon intraperitoneal administration to the mice before or after the tumor inoculation. The tannin also inhibited the growth of Meth-A solid type tumor in mice. This antitumor effect of the tannin could not be attributed to its direct cytotoxic action on tumor cells, because the cytotoxicity was very weak in the presence of serum protein. When oenothein B was injected into the peritoneal cavity of mice, peritoneal exudate cells, including cytostatic macrophages, were induced. Furthermore, in the in vitro treatment of macrophages from mice and humans, the tannin stimulated release of an interleukin 1 (IL-1)-like activity and IL-1 beta from the cells. These results suggest that oenothein B exerts its antitumor effect through potentiation of the host-immune defense via activation of macrophages.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Survival; Female; Fibrosarcoma; Hydrolyzable Tannins; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Picibanil; Sarcoma, Experimental; Tannins; Tumor Cells, Cultured

Topics: Animals; Caffeine; Drug Evaluation, Preclinical; Female; Fibrosarcoma; Injections, Subcutaneous; Plant Extracts; Plants; Rats; Sarcoma, Experimental; Tannins; West Indies

Topics: Animals; Cats; Connective Tissue; Fibrosarcoma; Humans; Hydroquinones; Indicators and Reagents; Kidney; Liver; Lung; Lymph Nodes; Lymphoma; Lymphoma, Large B-Cell, Diffuse; Mouth Mucosa; Muscles; Mycosis Fungoides; Neurons; Phosphotungstic Acid; Silver Proteins; Spleen; Staining and Labeling; Tannins; Tungsten