Anti-angiogenic effects and mechanisms of polysaccharides from Antrodia cinnamomea through immunomodulation

• Main Authors: Yu-Chieh Chou, 周郁傑
• Other Authors: 胡淼琳
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/59994066016235559933

碩士 === 國立中興大學 === 食品暨應用生物科技學系 === 94 === Metastasis is one of the major causes of cancer-associated mortality, and angiogenesis is a key step in the growth and metastasis of tumor cells. Angiogenesis is regulated by several angiogenic or angiostatic factors including vascular endotheilial growth factor (VEGF), Interleukin(IL)-8, IL-12, and others. Antrodia (A.) cinnamomea is a species known to be available only in Taiwan. Polysaccharides isolated from A. cinnamomea mycelia (AC-PS) elicit its anti-tumor effect by activating host immune response in both in vitro and in vivo models. However, there are few reports on the anti-angiogenic activity of AC-PS, and little is known about its mechanisms of action. In this study, we determined the anti-angiogenic activity of AC-PS in vitro. Furthermore, we investigated the anti-angiogenic mechanism of AC-PS in different molecular-weight (MW) fractions of AC-PS. The polysaccharides were isolated from the mycelia of A. cinnamomea using ethanol precipitation methods and fractionated into four MW fractions (＜5 kD, 5~30 kD, 30~100 kD, and ＞100 kD). We first pre-incubated human mononuclear cells (MNC) with different MW fractions of AC-PS to investigate these immunomodulatory effects. We found that Interleukin-12 (IL-12) and Interferon-γ (IFN-γ) levels in AC-PS-MNC-CM were significantly increased in a dose-dependent manner (p＜0.0001 and p＜0.0001, respectively) in the fraction with MW＞100 kD; at 100 μg/ml, IL-12 and IFN-γ increased 27.7 and 3.3 folds, respectively, as compared to the control. Then, we pre-incubated human leukemia cells (HL-60) and human umbilical vein endothelial cells (HUVECs) with AC-PS-stimulated-MNC-conditioned medium (AC-PS-MNC-CM) to investigate the anti-angiogenic effect and mechanisms underlying the action of AC-PS. In the fraction with MW＞100 kD, VEGF secretion in HL-60 was significantly decreased in a dose-dependent manner (p＜0.05). Similar phenomenon was observed on Matrigel tube formation of HUVECs (pretreated with AC-PS-MNC-CM) in the fraction with MW＞100 kD but not in other MW fractions. These results suggeste that AC-PS with MW＞100 kD elicit its anti-angiogenic activities through immunomodulation, and that these effects are attributed to the regulation of release of IL-12 and IFN-γ, the activation by IL-12 directly, and the inhibition of VEGF secretion in tumors mediated by IL-12 from activated mononuclear cells.