The recruitment of bone marrow-derived endothelial progenitor cells (EPCs) facilitates physiological and pathological processes involved in new blood vessel synthesis. Glucocerebroside, an extract of Cordyceps militaris, inhibits inflammatory cytokine production and monocyte migration, although its anti-angiogenic properties in human EPCs has remained largely unknown up until now. We describe how glucocerebroside reduces migration as well as tube formation induced by vascular endothelial growth factor (VEGF) stimulation in human EPCs, without affecting cell viability. This inhibitory effect was achieved through the focal adhesion kinase (FAK)/c-Src pathways. We also found that glucocerebroside reduced VEGFpromoted upregulation of the transcription factor Runx2 in the EPCs. The in vivo chick embryo chorioallantoic membrane model demonstrated that glucocerebroside reduces new vessel formation. Our investigation is the first to show that glucocerebroside reduces angiogenesis in human EPCs and to describe the underlying mechanisms. Further investigations are needed to examine the effects of glucocerebroside in other angiogenesis-related disorders.
ARTICLE HISTORY
Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Adiponectin is a protein hormone secreted predominantly by differentiated adipocytes. On the other hand, angiogenesis is a critical step in tumor growth and metastasis. However, the relationship of adiponectin with vascular endothelial growth factor-A (VEGF-A) expression and angiogenesis in human chondrosarcoma is mostly unknown. In this study we first demonstrated that the expression of adiponectin was correlated with tumor stage of human chondrosarcoma tissues. In addition, we also found that adiponectin increased VEGF-A expression in human chondrosarcoma cells and subsequently induced migration and tube formation in human endothelial progenitor cells (EPCs). Adiponectin promoted VEGF-A expression through adiponectin receptor (AdipoR), phosphoinositide 3 kinase (PI3K), Akt, mammalian target of rapamycin (mTOR), and hypoxia-inducible factor-1α (HIF)-1α signaling cascades. Knockdown of adiponectin decreased VEGF-A expression and also abolished chondrosarcoma conditional medium-mediated tube formation in EPCs in vitro as well as angiogenesis effects in the chick chorioallantoic membrane and Matrigel plug nude mice model in vivo. Therefore, adiponectin is crucial for tumor angiogenesis and growth, which may represent a novel target for anti-angiogenic therapy in human chondrosarcoma.
Rheumatoid arthritis (RA) is characterised by the infiltration of a number of proinflammatory cytokines into synovial fluid. Soyacerebroside, an extract from Cordyceps militaris, inhibits synovial inflammation and reduces cartilage damage in an osteoarthritis model, although the role of soya-cerebroside in inflammatory cytokine expression in RA is uncertain. In this study, Gene Expression Omnibus (GEO) database records revealed higher levels of interleukin (IL)-1β, IL-6 and IL-8 in RA tissue compared with normal tissue. Elevated levels of these inflammatory cytokines were also higher in mice with collagen-induced arthritis (CIA) than in control mice. Soya-cerebroside effectively inhibited IL-1β, IL-6 and IL-8 expression in RA synovial fibroblasts, apparently by inhibiting the ERK, NF-κB and AP-1 signalling pathways. This antiinflammatory agent shows promise for the treatment of RA.
Antrodia cinnamomea is a well‐known medicinal mushroom in Taiwan that exhibits anti‐inflammatory biological activities. In rheumatoid arthritis (RA), chronic inflammation and angiogenesis driven by proinflammatory cytokines reflect the severity of the disease. Although biological treatments have improved the outlook for RA, no healing exists. Moreover, the available pharmacotherapies do not work for all patients and drug safety is a major consideration. Investigations into plant‐based medicines hope to reveal better, more tolerable agents. We examined whether Antcin K, a phytosterol isolated from A. cinnamomea, has anti‐angiogenic activity in RA. The GSE12021 gene dataset from the Gene Expression Omnibus (GEO) database was examined for levels of vascular endothelial growth factor (VEGF) expression in 10 RA and 10 osteoarthritis (OA) synovial tissue samples. In clinical samples, VEGF expression was analyzed by immunohistochemical staining and ELISA in normal and RA synovial tissue, as well as OA and RA synovial fluid. Collagen‐induced arthritis (CIA) and control tissue was stained with hematoxylin and eosin (H&E) for histological changes; Safranin O/Fast Green staining examined histopathological changes and evidence of bone erosion. Human RA synovial fibroblasts (RASFs) were incubated with Antcin K and cell viability was examined by the MTT assay. VEGF mRNA expression was detected in RASFs using qPCR. Antcin K significantly inhibited VEGF expression and ameliorates endothelial progenitor cell (EPC) migration and tube formation in RASFs by downregulating the phospholipase C‐γ/protein kinase C‐α pathway. Antcin K also induced anti‐angiogenic effects in human RASFs without cytotoxicity.
Practical applications
Analysis of GEO dataset samples and human synovial fluids or synovial tissues revealed higher VEGF levels in rheumatoid arthritis (RA) samples compared with osteoarthritis (OA) and healthy control samples. VEGF levels were also higher in mice with collagen‐induced arthritis (CIA) than in healthy controls. Antcin K markedly suppressed VEGF expression in human RA synovial fibroblasts and inhibited the migration and tube formation of epithelial progenitor cells (EPCs) by downregulating the phospholipase C‐γ/protein kinase C‐α pathway. Further investigations are warranted to examine the effects of Antcin K in other angiogenesis‐associated disorders.
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