Types Of Endothelial Progenitor Cells Research Articles

Rivaroxaban enhances thrombin-induced endothelial progenitor cell activation

Background and Aims: Factor Xa (FXa) and thrombin exert non-haemostatic cellular effects. Late-outgrowth endothelial cells (OECs) are a type of endothelial progenitor cells. We investigated the effect of rivaroxaban, a direct oral anticoagulant which specifically inhibits FXa’s activity, on FXa-and thrombin-induced OEC activation, using as activation markers the ICAM-1 membrane expression and MCP-1 secretion.

Factor Xa and thrombin induce endothelial progenitor cell activation. The effect of direct oral anticoagulants

Factor Xa (FXa) and thrombin exert non-hemostatic cellular actions primarily mediated through protease-activated receptors (PARs). We investigated the effect of FXa and thrombin on human late-outgrowth endothelial cells (OECs), a type of endothelial progenitor cells (EPCs), and on human umbilical vein endothelial cells (HUVECs). The effect of direct oral anticoagulants (DOACs), rivaroxaban and dabigatran, was also studied. The membrane expression of intercellular adhesion molecule-1 (ICAM-1) and the secretion of monocyte chemoattractant protein-1 (MCP-1) were used as cell activation markers. FXa and thrombin increase the ICAM-1 expression and the MCP-1 secretion on both cells, being higher on OECs. Vorapaxar, a specific PAR-1 antagonist, completely inhibits FXa-induced activation of both cells and thrombin-induced HUVEC activation, but only partially thrombin-induced OEC activation. Furthermore, thrombin-receptor activating peptide; TRAP-6, only partially activates OECs. OECs do not membrane-express PAR-4, therefore it may not be involved on thrombin-induced OEC activation. Rivaroxaban and dabigatran inhibit OEC and HUVEC activation by FXa and thrombin, respectively. Rivaroxaban enhances thrombin-induced OEC and HUVEC activation, which is completely inhibited by vorapaxar. The inhibition of OEC and HUVEC activation by vorapaxar and DOACs may represent a new pleiotropic effect of these drugs. The pathophysiological and clinical significance of our findings need to be established.

Isolation and characterization of endothelial progenitor cells from canine bone marrow

ABSTRACT Endothelial progenitor cells (EPC) are located predominantly in the bone marrow. These cells are useful for treating human vascular diseases; they also are a possible target for restricting blood vessel growth for tumors. Little is known about canine EPC. We investigated a bone marrow EPC isolation method that combines the whole bone marrow culture method and the differential adherent speed method using stillborn canines. MTT proliferation, flow cytometry detection, Dil-ac-LDL uptake, FITC-UEA-1 binding and matrigel assays were used to identify and characterize EPC. We isolated two types of EPC: early EPC and late EPC. We found that isolated cells produced typical colony and cobblestone morphology, and were positive for CD31, CD34, CD133 and VEGFR-2. Significant differences were observed in the intensity of expression between early and late EPC, which suggests their different roles during angiogenesis and vasculogenesis. Both early and late EPC were positive for Dil-ac-LDL and FITC-UEA-1, and displayed tube formation when re-suspended in matrigel, both of which are important functional criteria for identifying EPC. Our method is a novel, effective and efficient way to produce enriched EPC.

P3475Dabigatran inhibits the activation of endothelial progenitor cells induced by thrombin

Abstract Introduction Thrombin is a coagulation serine protease, which also activates various cell types, including endothelial cells. Late-outgrowth endothelial cells (OECs) are a type of endothelial progenitor cells that contribute to endothelial regeneration and angiogenesis. Dabigatran is a direct oral anticoagulant that inhibits thrombin's action and is widely used in everyday clinical practice. Purpose We investigated the effect of dabigatran on thrombin-induced activation of OECs, using the membrane expression of adhesion molecule ICAM-1 as activation marker. Control experiments were conducted in mature human umbilical vein endothelial cells (HUVECs). Methods CD34+ cells were isolated from cord blood mononuclear cells, using human CD34 Microbead Kit and appropriately cultured for OEC formation. HUVECs were purchased from Lonza. Confluent OECs and HUVECs were incubated with 10 or 20 μM dabigatran for 10 min, before activation with 8 U/mL thrombin, for 24 h. The effect of dabigatran on ICAM-1 expression (anti-CD54-PE) was evaluated in both cell types as % gated CD31+/CD54+ cells, using flow cytometry. Results Thrombin induced ICAM-1 membrane expression by 33±15% on OECs and by 123±22% on HUVECs, compared with respective untreated cells (p<0.05 for both comparisons, from 6 different experiments). Dabigatran at 10 μM significantly inhibited ICAM-1 expression by 36±7% on OECs and 57±8% on HUVECs, as well as at 20 μM by 51±8% on OECs and 79±7% on HUVECs (p<0.05 for all comparisons, from 4 different experiments). Conclusions We show for the first time that dabigatran at concentrations relevant to those existing in vivo after oral administration, inhibits the thrombin-induced membrane expression of the adhesion molecule ICAM-1 on OECs, a phenomenon that is also observed on mature endothelial cells. The significance of this effect regarding the pathophysiological role of OECs and mature endothelial cells at the clinical level remains to be established. Acknowledgement/Funding Operational Program “Human Resources Development, Education and Lifelong Learning”. Co-financed by the European Union and Greek national funds

Platelets of Healthy Origins Promote Functional Improvement of Atherosclerotic Endothelial Progenitor Cells.

The purpose was to evaluate the effect of platelets on functional properties of late endothelial progenitor cells (EPCs), in the direct co-culture conditions, and to investigate the involved mediators, in experimental induced atherosclerosis. The late EPCs obtained from two animal groups, hypertensive-hyperlipidemic (HH) and control (C) hamsters, named late EPCs-HH and late EPCs-C, were co-incubated with or without platelets isolated from both groups. Our results have showed that exposure to platelets from control animals: (i) promoted the late EPCs-C capacity to form colonies and capillary-like structures, and also to proliferate and migrate; (ii) improved the functional properties of late EPCs-HH; (iii) strengthened the direct binding EPCs-platelets; (iv) increased SDF-1α,VEGF, PDGF, and reduced CD40L, IL-1β,-6,-8 levels; and (v) enhanced miR-223 and IGF-1R expressions. Platelets from HH group diminished functional abilities for both EPC types and had opposite effects on these pro-angiogenic and pro-inflammatory molecules. Furthermore, testing the direct effect of miR-223 and IGF-1R on late EPCs disclosed that these molecular factors improve late EPC functional properties in atherosclerosis in terms of stimulation of the proliferation and migration abilities. In conclusion, in vitro exposure to platelets of healthy origins had a positive effect on functional properties of atherosclerotic late EPCs. The most likely candidates mediating EPC-platelet interaction can be SDF-1α, VEGF, CD40L, PDGF, IL-1β,-6,-8, miR-223, and IGF-1R. The current study brings evidences that the presence of healthy origin platelets is of utmost importance on functional improvement of EPCs in atherosclerosis.

Invited commentary

Invited commentary

Isolation of Endothelial Progenitor Cells from Human Umbilical Cord Blood.

The existence of endothelial progenitor cells (EPCs) in peripheral blood and its involvement in vasculogenesis was first reported by Ashara and colleagues1. Later, others documented the existence of similar types of EPCs originating from bone marrow2,3. More recently, Yoder and Ingram showed that EPCs derived from umbilical cord blood had a higher proliferative potential compared to ones isolated from adult peripheral blood4,5,6. Apart from being involved in postnatal vasculogenesis, EPCs have also shown promise as a cell source for creating tissue-engineered vascular and heart valve constructs7,8. Various isolation protocols exist, some of which involve the cell sorting of mononuclear cells (MNCs) derived from the sources mentioned earlier with the help of endothelial and hematopoietic markers, or culturing these MNCs with specialized endothelial growth medium, or a combination of these techniques9. Here, we present a protocol for the isolation and culture of EPCs using specialized endothelial medium supplemented with growth factors, without the use of immunosorting, followed by the characterization of the isolated cells using Western blotting and immunostaining.

Isolation of Endothelial Progenitor Cells from Human Umbilical Cord Blood

The existence of endothelial progenitor cells (EPCs) in peripheral blood and its involvement in vasculogenesis was first reported by Ashara and colleagues1. Later, others documented the existence of similar types of EPCs originating from bone marrow2,3. More recently, Yoder and Ingram showed that EPCs derived from umbilical cord blood had a higher proliferative potential compared to ones isolated from adult peripheral blood4,5,6. Apart from being involved in postnatal vasculogenesis, EPCs have also shown promise as a cell source for creating tissue-engineered vascular and heart valve constructs7,8. Various isolation protocols exist, some of which involve the cell sorting of mononuclear cells (MNCs) derived from the sources mentioned earlier with the help of endothelial and hematopoietic markers, or culturing these MNCs with specialized endothelial growth medium, or a combination of these techniques9. Here, we present a protocol for the isolation and culture of EPCs using specialized endothelial medium supplemented with growth factors, without the use of immunosorting, followed by the characterization of the isolated cells using Western blotting and immunostaining.

Occludin as a functional marker of vascular endothelial cells on tube-forming activity.

Cell therapy using endothelial progenitor cells (EPCs) is a promising strategy for the treatment of ischemic diseases. Two types of EPCs have been identified: early EPCs and late EPCs. Late EPCs are able to form tube structure by themselves, and have a high proliferative ability. The functional marker(s) of late EPCs, which relate to their therapeutic potential, have not been fully elucidated. Here we compared the gene expression profiles of several human cord blood derived late EPC lines which exhibit different tube formation activity, and we observed that the expression of occludin (OCLN) in these lines correlated with the tube formation ability, suggesting that OCLN is a candidate functional marker of late EPCs. When OCLN was knocked down by transfecting siRNA, the tube formation on Matrigel, the S phase + G2 /M phase in the cell cycle, and the spheroid-based sprouting of late EPCs were markedly reduced, suggesting the critical role of OCLN in tube formation, sprouting, and proliferation. These results indicated that OCLN plays a novel role in neovascularization and angiogenesis.

Preconditioned Endothelial Progenitor Cells as Biomarker of Vascular Reparation?

The endothelial progenitor cells (EPCs) have defined as cells positively labeled with both hematopoietic stem cells (CD34) and endothelial cell markers predominantly VEGF receptor-2 (VEGFR2) cumulatively. Therefore, there are at least two types of EPCs labelled as early outgrowth EPCs and late outgrowth EPCs probably distinguished their vascular protective ability. Recent animal and clinical studies have shown that reduced number and weak function of EPCs may not only indicate to higher CV risk, but contribute to the impaired heart and vessels reparation. Interestingly, there are some subpopulations of EPCs especially recruited from peripheral blood cells, which may exhibit very variable pro-angiogenic effect and endothelial repair capacity and they are called “preconditioned” EPCs. The aim of the short commentary is depicted the possibilities to use of measurement of traditionally labeled EPCs as biomarker of cardiovascular risk.

Cord blood-derived endothelial colony-forming cell function is disrupted in congenital diaphragmatic hernia.

Vascular growth is necessary for normal lung development. Although endothelial progenitor cells (EPCs) play an important role in vascularization, little is known about EPC function in congenital diaphragmatic hernia (CDH), a severe neonatal condition that is associated with pulmonary hypoplasia. We hypothesized that the function of endothelial colony-forming cells (ECFCs), a type of EPC, is impaired in CDH. Cord blood (CB) was collected from full-term CDH patients and healthy controls. We assessed CB progenitor cell populations as well as plasma vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1α (SDF1α) levels. CB ECFC clonogenicity; growth kinetics; migration; production of VEGF, SDF1α, and nitric oxide (NO); vasculogenic capacity; and mRNA expression of VEGF-A, fms-related tyrosine kinase 1 (FLT1), kinase insert domain receptor (KDR), nitric oxide synthase (NOS) 1-3, SDF1, and chemokine (C-X-C motif) receptor 4 (CXCR4) were also assessed. Compared with controls, CB ECFCs were decreased in CDH. CDH ECFCs had reduced potential for self-renewal, clonogenicity, proliferation, and migration. Their capacity for NO production was enhanced but their response to VEGF was blunted in CDH ECFCs. In vivo potential for de novo vasculogenesis was reduced in CDH ECFCs. There was no difference in CB plasma VEGF and SDF1α concentrations, VEGF and SDF1α production by ECFCs, and ECFC mRNA expression of VEGF-A, FLT1, KDR, NOS1-3, SDF1, and CXCR4 between CDH and control subjects. In conclusion, CB ECFC function is disrupted in CDH, but these changes may be caused by mechanisms other than alteration of VEGF-NO and SDF1-CXCR4 signaling.

Endothelial Progenitors and Blood Microparticles: Are They Relevant to Heart Failure With Preserved Ejection Fraction?

Endothelial Progenitors and Blood Microparticles: Are They Relevant to Heart Failure With Preserved Ejection Fraction?

Research and clinical applications regarding endothelial progenitor cell transplantation

Endothelial injury or dysfunction leads to multiple cardiovascular diseases, such as atherosclerosis, myocardial infarction, stroke, hypertension and peripheral vascular disease. Endothelial progenitor cells (EPCs) are precursor cells of endothelial cells, including the early endothelial progenitor cells and the late endothelial progenitor cells. These two EPC types have different function and surface markers. EPC in this article mainly means late endothelial progenitors which could grow into endothelial cloning and form vessels in vivo. Late EPCs can express CD133, CD31, KDR, CD144, CD34 etc, take in low density lipoprotein, bind with ulex europaeus lectin 1 and form blood vessels in vitro and in vivo. EPCs not only participate in new blood vessels formation, but also are closely related to the repair of damaged endothelium. Many studies confirm that the transplanted EPCs are able to be mobilized to vascular injury location and repair the damaged endothelial cells thus promote new blood vessel formation, which provides a promising strategy for the treatment of cardiovascular diseases and ischemic diseases.

MiRNome traits analysis on endothelial lineage cells discloses biomarker potential circulating microRNAs which affect progenitor activities

BackgroundEndothelial progenitor cells (EPCs) play a fundamental role in not only blood vessel development but also post-natal vascular repair. Currently EPCs are defined as early and late EPCs based on their biological properties and their time of appearance during in vitro culture. Both EPC types assist angiogenesis and have been linked to ischemia-related disorders, including coronary artery disease (CAD).ResultsWe found late EPCs are more mobile than early EPCs and matured endothelial cells (ECs). To pinpoint the mechanism, microRNA profiles of early EPCs late EPCs, and ECs were deciphered by small RNA sequencing. Obtained signatures made up of both novel and known microRNAs, in which anti-angiogenic microRNAs such as miR-221 and miR-222 are more abundant in matured ECs than in late EPCs. Overexpression of miR-221 and miR-222 resulted in the reduction of genes involved in hypoxia response, metabolism, TGF-beta signalling, and cell motion. Not only hamper late EPC activities in vitro, both microRNAs (especially miR-222) also hindered in vivo vasculogenesis in a zebrafish model. Reporter assays showed that miR-222, but not miR-221, targets the angiogenic factor ETS1. In contrast, PIK3R1 is the target of miR-221, but not miR-222 in late EPCs. Clinically, both miR-221-PIK3R1 and miR-222-ETS1 pairs are deregulated in late EPCs of CAD patients.ConclusionsOur results illustrate EPCs and ECs exploit unique miRNA modalities to regulate angiogenic features, and explain why late EPC levels and activities are reduced in CAD patients. These data will further help to develop new plasma biomarkers and therapeutic approaches for ischemia-related diseases or tumor angiogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-802) contains supplementary material, which is available to authorized users.

Endothelial progenitor cells and response to ranibizumab in age-related macular degeneration.

Choroidal neovascularization (CNV) is the main cause of vision loss in age-related macular degeneration (AMD). In experimental CNV, endothelial progenitor cells (EPCs) contribute to the formation of new vessels. The aim of this study was to investigate whether the behavior of EPCs in patients with AMD supports a role for EPCs in human CNV. The number of circulating EPCs that are considered pure endothelial precursors and EPCs with monocytic characteristics, and the plasma levels of regulatory cytokines were evaluated in 23 patients with AMD with active CNV and 20 matched controls. In the patients, this profile was re-evaluated after ranibizumab. When compared with controls, the patients with AMD showed a lower number of both EPC types (P = 0.03) and higher plasma levels (P = 0.03) of stromal cell-derived factor 1. Three monthly injections of ranibizumab returned to control levels the number of circulating EPCs considered pure endothelial precursors and of stromal cell-derived factor 1, but not of monocytic EPCs. The observations indicate responsiveness of circulating EPCs to the CNV process in AMD. They suggest the hypothesis that increased stromal cell-derived factor 1 production at the CNV site (reflected in higher plasma levels) recruits EPCs from the circulation, and that antivascular endothelial growth factor therapy selectively decreases the recruitment of cells to be incorporated into new vessels.

Adherence to lifestyles modifications after a Cardiac Rehabilitation program (CR) and Endothelial Progenitor Cells (EPCs): a 6-months follow-up study

Background: A significant increase of EPCs number among acute coronary syndrome (ACS) patients participating in a CR program has recently been reported, but no data on the impact of adherence to lifestyle recommendations provided during a CR program on EPCs number are available. Aim: To investigate the effects of adherence to lifestyles' recommendations on EPCs, inflammatory and functional parameters after 6 months from a CR program in ACS patients. Methods: One hundred-ten out of 112 ACS patients (90M/20 F; mean age 57.9±9.4 years) completed the study. EPCs, high sensitivity C-reactive protein (hsCRP), NT-ProBNP levels, and cardiopulmonary testings were determined at the end of the program (T1) and at a 6 month follow-up (T2). At T2, a questionnaire assessing dietary habits and physical activity in the previous 6 months was obtained. EPCs were defined as CD34+KDR+, CD133+KDR+ and CD34+CD133+KDR+. hsCRP and NT-ProBNP were measured by nephelometric and immunometric method, respectively. Results: At T2, we observed a significant decrease of all the three types of EPCs [CD34+KDR+ 10 (0-37) vs. 7 (0-43) p=0.01; CD133+KDR+ 10 (0-33) vs. 7 (0-43) p=0.03; CD34+CD133+KDR+ 10 (0-33) vs. 7 (0-43) p=0.03], of CRP (p=0.009) as well as of NT-ProBNP (p<0.0001). On the basis of dietary habits and physical activity we divided patient population into three categories (no/low adherence to lifestyles' recommendations, moderate adherence; high adherence). An increased adherence to lifestyle recommendations associated to a significant increase in EPCs and Watt max variations between T1 and T2 was observed (Δ CD34+KDR+ p for trend=0.04; Δ CD133+KDR+ p for trend=0.02; Δ CD34+CD133+KDR+ p for trend=0.02; Δ Watt max p for trend=0.003). Moreover, the group of patients who reported at the end of the CR program an increase of EPCs and baseline levels of CRP in the lowest tertile (< 2.2 mg/dL) showed, at a 6-month of follow-up, significant higher levels of EPCs (p=0.03), Watt max (p=0.003) and VO2max (p=0.002) and significant lower CRP levels (p=0.01). Conclusions: Adherence to lifestyles recommendations provided during a CR program is able to influence variations of EPCs' and Watt max, at 6-month follow-up.

CD34 Hybrid Cells Promote Endothelial Colony-Forming Cell Bioactivity and Therapeutic Potential for Ischemic Diseases

Although endothelial progenitor cells (EPCs) have been reported to promote neovessel formation during vascular injury, the function of supporting cells of EPCs and their interaction with EPCs during EPC isolation remain unclear. We investigated the functional properties of 2 types of EPCs, also known as endothelial colony-forming cells (ECFCs), CD34(-)/CD34(+) cell-derived ECFCs (hybrid-dECFCs) and CD34(+) cell-derived ECFCs (stem-dECFCs), isolated using different methods, to elucidate the role of CD34(-) cell populations as cell-supporting niches. Using EPC colony-forming and insert coculture assays, we found that CD34(-) accessory cells dynamically modulate hematopoietic stem cell-derived endothelial cell progenitor commitment via angiogenic cytokines secreted by CD34(-)/CD11b(+) macrophages. On the basis of these findings, we isolated 2 types of ECFCs and investigated their bioactivities. We found that stem-dECFCs showed remarkably retarded cell growth, enhanced senescence, and decreased characteristics of ECFCs, whereas hybrid-dECFCs showed greater proliferative properties but delayed senescence. In a murine hind-limb ischemia model, hybrid-dECFCs showed significantly enhanced blood perfusion, capillary density, transplanted cell survival and proliferation, and angiogenic cytokine secretion compared with stem-dECFCs. In particular, the migratory capacity of hybrid-dECFCs was significantly enhanced, in part mediated via an augmented phosphorylation cascade of focal adhesion kinase and Src, resulting in a highly increased incorporation capacity of hybrid-dECFCs compared with stem-dECFCs. CD34(-) accessory cells of hybrid-dECFCs might be niche-supporting cells that facilitate cell survival, increase the secretion of angiogenic cytokines, and increase incorporation. This study provided important insight into blood vessel formation and repair in ischemic diseases for ECFC-based cell therapy.

Differential Regulation of Bone Marrow-Derived Endothelial Progenitor Cells and Endothelial Outgrowth Cells by the Notch Signaling Pathway

Endothelial progenitor cells (EPCs) are heterogeneous populations of cells that participate in vasculogenesis and promote tissue regeneration. However the different roles of EPC populations in vasculogenesis and tissue regeneration, as well as their regulation and mechanisms remain elusive. In the present study, we cultured bone marrow (BM)-derived early EPCs (EEPCs) and endothelial outgrowth cells (EOCs), and investigated their roles in liver regeneration and their regulation by the Notch signaling pathway. We found that Notch signaling exhibited different effects on the proliferation and migration of EEPCs and EOCs. Our results also showed that while EEPCs failed to form vessel-like structures in a three dimensional sprouting model in vitro, EOCs could sprout and form endothelial cords, and this was regulated by the Notch signaling. We further showed that, by using a conditional knockout model of RBP-J (the critical transcription factor mediating Notch signaling), Notch signaling differentially regulates EEPCs and EOCs. In a partial hepatectomy (PHx) model, EEPCs Notch-dependently benefitted liver regeneration with respect to liver function and hepatocyte proliferation and apoptosis. In contrast, EOCs appeared not directly involved in the recovery of liver function and the increase of hepatocytes. These data suggested that the RBP-J-mediated Notch signaling differentially regulated the two types of EPCs, which showed different roles in liver regeneration.

Effect of preeclampsia and intrauterine growth restriction on endothelial progenitor cells in human umbilical cord blood

Objectives: Endothelial progenitor cells (EPCs) might play important roles in vascular homeostasis. This study evaluated the influence of prematurity, preeclampsia (PE) and intrauterine growth restriction (IUGR) on the EPC population in human umbilical cord blood (CB). Methods: CB was obtained from 19 preterm and 27 term deliveries. Mononuclear cells were isolated by gradient centrifugation and subjected to flow cytometry to obtain percentages of CD45(d) CD34+, CD45(d) CD133+, CD 45(d) CD34+ CD133+, and CD45(d) CD34+ CD133+ VEGFR-2+ cells. Clinical data were obtained using chart review. Results: Percentages of EPCs were comparable between preterm and term cord blood. CD45(d) CD34+ CD133+ cells were significantly decreased in CB samples obtained from women with PE (n = 14) [0.01, (0.00–2.6), [median, (range)], as compared to those without PE (n = 32) [1.74 (0.00–3.1)] (p = 0.005). CD45(d) CD133+ CD34− cells were significantly increased in presence of PE [0.43, (0.06–1.38)], (p = 0.002). CD45(d) CD34+ CD133+ cells were significantly decreased in presence of IUGR, with no change in CD45(d) CD133+ CD34− cells. Differences in EPC types associated with PE and IUGR were present only in term CB. Conclusions: Exposure to PE and IUGR is associated with significant changes in EPC population. Future studies are needed to explore the clinical impact of observed changes.

Ginsenoside Rg3 attenuates tumor angiogenesis via inhibiting bioactivities of endothelial progenitor cells

Accumulating evidence suggests that Ginsenoside Rg3 appears to inhibit tumor growth including Lewis lung carcinoma, intestinal adenocarcinomas or B16 melanoma by inhibiting cell proliferation, tumor cell invasion and metastasis. Endothelial progenitor cells (EPCs) appear to play a key role in the growth of early tumors by intervening with the angiogenic switch promoting tumor neovessel formation by producing angiogenic cytokines during tumor progression. This paper reports a novel mechanism of Ginsenoside Rg3, a candidate anticancer bio-molecule, on tumor angiogenesis by inhibiting the multiple bioactivities of EPCs. When Ginsenoside Rg3 was applied to the ex vivo cultured outgrowth ECs, a type of EPCs, it inhibited the cell proliferation, cell migration and tubular formation of EPCs. Importantly, Ginsenoside Rg3 attenuated the phosphorylation cascade of the VEGF dependent p38/ERK signaling in vitro. The xenograft tumor model clearly showed that Ginsenoside Rg3 suppresses tumor growth and tumor angiogenesis by inhibiting the mobilization of EPCs from the bone marrow microenvironment to the peripheral circulation and modulates VEGF-dependent tumor angiogenesis. In conclusion, this study provides a potential therapeutic molecule, Ginsenoside Rg3, as an anticancer drug by inhibiting the EPC bioactivities.