Heparin, which has been used as an anticoagulant drug for decades, inhibits angiogenesis, whereas thrombin promotes tumor-associated angiogenesis. However, the mechanisms underlying the regulation of angiogenesis by heparin and thrombin are not well understood. Here, we show that microRNA-10b (miR-10b) is down-regulated by heparin and up-regulated by thrombin in human microvascular endothelial cells (HMEC-1). Overexpression of miR-10b induces HMEC-1 cell migration, tube formation, and angiogenesis, and downregulates homeobox D10 (HoxD10) expression via direct binding of miR-10b to the putative 3 UTR of HoxD10. In addition, HMEC-1 cell migration and tube formation are induced by HoxD10 knockdown, whereas angiogenesis is arrested when HoxD10 expression is increased after anti-miR-10b or heparin treatments. Furthermore, expression of miR-10b and its transcription factor Twist are up-regulated by thrombin, whereas HoxD10 expression is impaired by thrombin. Using quartz crystal microbalance analysis, we show that heparin binds to thrombin, thereby inhibiting thrombin-induced expression of Twist and miR-10b. However, the expression of miR-10b is not attenuated by heparin any more after thrombin expression is silenced by its siRNA. Interestingly, we find that heparin attenuates miR10b expression and induces HoxD10 expression in vivo to inhibit angiogenesis and impair the growth of MDA-MB-231 tumor xenografts. These results provide insight into the molecular mechanism by which heparin and thrombin regulate angiogenesis.Thrombosis is considered an early clinical indication and frequent complication of cancer (1, 2). Malignant tumors often exhibit increased expression of tissue factor and cancer procoagulant, which can be followed by activation of cell surface protease receptors and fibrin generation (3). In addition, tumor cells can interact with blood cells, particularly monocytes, macrophages, and platelets, leading to the generation of thrombin and thrombosis through the clotting cascade or platelet activation (4). Moreover, aggressive antitumor therapies such as chemotherapy, radiation, and surgery also increase the risk of thrombosis.Positive feedback signaling loops exist between tumor tissue and the coagulation system (5, 6). For instance, it is widely accepted that elements of the coagulation and fibrinolytic system may aid in cancer cell survival, proliferation, invasion, and metastasis, as well as tumor angiogenesis (7). Therefore, inhibition of the activation of coagulation could be a useful antitumor strategy. A number of studies have shown that anticoagulant drugs can extend survival in patients with certain types of cancer (8), and studies are currently ongoing to confirm the effects of anticoagulant therapy in a range of tumor types. However, the molecular mechanisms involved in the action of anticoagulants in this process are not well understood.Heparins, in particular those of low molecular weight, are effective in the prevention and treatment of thromboembolic events in cancer patients (9, 10). As early...

A soluble homogeneous β-glucan, GFPBW1, with a molecular mass of 300 kDa was purified from the fraction of the fruit bodies of Grifola frondosa extracted with 5% NaOH. Using various methods, such as infrared spectroscopy, NMR, methylation and monosaccharide composition analysis, its structure was determined to be a β-D-(1-3)-linked glucan backbone with a single β-D-(1-6)-linked glucopyranosyl residue branched at C-6 on every third residue. It induced TNF-α and IL-6 production and the activation of Syk and NF-κB signaling in resident peritoneal macrophages from ICR mice, which could be significantly inhibited by the blocking reagent laminarin. A competitive phagocytosis assay with FITC-zymosan indicated that GFPBW1 could bind to DC-associated C-type lectin 1 (Dectin-1). The TNF-α secretion and activation of Syk/NF-κB signaling triggered by GFPBW1 were enhanced in RAW264.7 cells overexpressing wild but not mutant (Δ38 and Y15S) Dectin-1. Furthermore, GFPBW1 potentiated the Concanavalin A-induced proliferative response of splenocytes and inhibited Sarcoma-180 growth allografted in ICR mice but not in immunodeficient BALB/c nu/nu mice. These results suggested that the antitumor activity of GFPBW1 was partially associated with the activation of macrophages via the Dectin-1/Syk/NF-κB signaling pathway. This molecule could be a promising biological response modifier with clear application for antitumor therapies.

Dihydroflavonol 4-reductase (DFR), which catalyzes the reduction of dihydroflavonols to leucoanthocyanins, is a key enzyme in the biosynthesis of anthocyanidins, proanthocyanidins, and other flavonoids of importance in plant development and human nutrition. This study isolated a full length cDNA encoding DFR, designated as SmDFR (GenBank Accession No. EF600682), by screening a cDNA library from a red callus line of Saussurea medusa, which is an endangered, traditional Chinese medicinal plant with high pharmacological value. SmDFR was functionally expressed in yeast (Saccharomyces cerevisiae) to confirm that SmDFR can readily reduce dihydroquercetin (DHQ) and dihydrokampferol (DHK), but it could not reduce dihydromyricetin (DHM). The deduced SmDFR structure shared extensive sequence similarity with previously characterized plant DFRs and phylogenetic analysis showed that it belonged to the plant DFR super-family. SmDFR also possessed flavanone 4-reductase (FNR) activity and can catalyze the conversion of eridictyol to luteoforol. Real-time PCR analysis showed that the expression level of SmDFR was higher in flowers compared with both leaves and roots. This work greatly enhances our knowledge of flavonoid biosynthesis in S. medusa and marks a major advance that could facilitate future genetic modification of S. medusa.