Co-culture Of Human Umbilical Vein Endothelial Cells Research Articles

Inhibition of CD38 Shows Anti-Leukemic Activity in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is characterized by an early failure of healthy hematopoiesis and a high relapse rate, caused by persistent leukemia initiating cells in the bone marrow niche. The hematopoietic stem cell niche in myeloid malignancies shows severe structural and functional alterations with an inflammatory response upon leukemia infiltration and impaired immunosurveillance. CD38 is a glycoprotein that is expressed on various immunoregulatory cells and commonly on AML blasts. Targeting CD38 by using the monoclonal antibody daratumumab showed high efficacy in multiple myeloma which is mediated by both cell-autonomous as well as immunomodulatory mechanisms. In this study we have investigated the anti-leukemic efficacy of daratumumab as well as its underlying mechanisms in AML.Using an in vitro co-culture model with different human AML cell lines together with a fibroblast cell line (MS-5) or human umbilical vein endothelial cells (HUVEC) revealed a significant reduction in AML cell growth upon daratumumab treatment in 5 of 8 AML cell lines. Interestingly, anti-leukemic activity of daratumumab was more pronounced when co-cultured with MS-5 stroma cells and to lower extent with HUVECs as compared to mono-cultured AML cells (mean cell reduction in MS-5 co-culture, range from 12.9 to 31%; in HUVEC co-culture, range from 1.9 to 24.1% and in mono-culture, range from 9.9 to 18%). To validate the anti-leukemic activity of daratumumab in human AML and to elaborate the microenvironment-mediated effects we created a 3D invitro model with HUVECs and human mesenchymal spheres cultured with primary AML or normal donor cells. We could demonstrate that this triple-culture model led to an increased growth support for both AML as well as normal donor samples as compared to mono-cultured cells. Adding daratumumab to mono-cultured AML cells reduced cell growth by only 7.2% (p<0.01), whereas the anti-leukemic efficacy increased to 35.6% in triple-cultured AML samples (p<0.05; n=10 replicates). Of note, daratumumab did not show any significant cytotoxicity in normal donor samples at any culture condition. The anti-leukemic efficacy of daratumumab in AML appeared to depend on the level of CD38 expression. Addition of tretinoin (ATRA) induced a ~4-fold increase of CD38 expression in AML blasts and to a lower extent in normal donor cells. In fact, combination of tretinoin and daratumumab led to an enhanced anti-leukemic activity in AML. As daratumumab has been shown to exert diverse effects in myeloma we next assessed the underlying mechanisms in AML. Upon daratumumab treatment there were no significant differences in blast proliferation and apoptosis as assessed by BrdU and Annexin V assays, nor did we observe any induction of differentiation. Given the strong immunological reactions induced by daratumumab we next performed effector function assays. While there was no increase in antibody dependent cellular cytotoxicity (ADCC) or complement dependent cytotoxicity (CDC), we observed a significant induction of antibody dependent phagocytosis (ADCP) with daratumumab compared to IgG1 control. Human macrophages showed a ~1.7-fold increase in phagocytosis of AML cell lines and primary human AML cells after daratumumab treatment.To prove the anti-leukemic activity of daratumumab in AML in vivo we intravenously transplanted primary human AML cells into immunodeficient NOD scid gamma (NSG) mice. Leukemic mice were treated with ATRA over 4 weeks and once weekly with either daratumumab or IgG1 control. Preliminary results show a reduction in circulating blasts with a significant decrease of leukemia burden in peripheral blood by ~42% (p=0.0354), while there were no significant changes in bone marrow infiltration (n=5-6 mice per group). Ongoing experiments will further elucidate the anti-leukemic efficacy of daratumumab in combination with low-dose cytarabine.In summary, we found that targeting CD38 shows promising anti-leukemic activity with both cell-autonomous and microenvironment-mediated effects in AML. Together with tretinoin und putatively low-dose chemotherapy the efficacy of daratumumab in AML could be increased. This combination of well tolerated drugs could present a new option of niche-targeted therapies in AML. DisclosuresDuehrsen:Janssen: Honoraria; Gilead: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Roche: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Research Funding.

Cardiac Stem Cell Patch Integrated with Microengineered Blood Vessels Promotes Cardiomyocyte Proliferation and Neovascularization after Acute Myocardial Infarction.

Cardiac stem cell (CSC) therapy has shown preclinical and clinical evidence for ischemic heart repair but is limited by low cellular engraftment and survival after transplantation. Previous versions of the cardiac patch strategy improve stem cell engraftment and encourage repair of cardiac tissue. However, cardiac patches that can enhance cardiomyogenesis and angiogenesis at the injured site remain elusive. Therapies that target cardiomyocyte proliferation and new blood vessel formation hold great potential for the protection against acute myocardial infarction (MI). Here, we report a new strategy for creating a vascularized cardiac patch in a facile and modular fashion by leveraging microfluidic hydrodynamic focusing to construct the biomimetic microvessels (BMVs) that include human umbilical vein endothelial cells (HUVECs) lining the luminal surface and then encapsulating the BMVs in a fibrin gel spiked with human CSCs. We show that the endothelialized BMVs mimicked the natural architecture and function of capillaries and that the resultant vascularized cardiac patch (BMV-CSC patch) exhibited equivalent release of paracrine factors compared to those of coculture of genuine human CSCs and HUVECs after 7 days of in vitro culture. In a rat model of acute MI, the BMV-CSC patch therapy induced profound mitotic activities of cardiomyocytes in the peri-infarct region 4 weeks post-treatment. A significant increase in myocardial capillary density was noted in the infarcted hearts that received BMV-CSC patch treatment compared to the infarcted hearts treated with conventional CSC patches. The striking therapeutic benefits and the fast and facile fabrication of the BMV-CSC patch make it promising for practical applications. Our findings suggest that the BMV-CSC patch strategy may open up new possibilities for the treatment of ischemic heart injury.

Engineering Microvascular Networks in LED Light-Cured Cell-Laden Hydrogels.

The success of tissue engineering inevitably depends on the fabrication of tissue constructs that can be vascularized and that anastomose with the host vasculature. In this report, we studied the effects of light-emitting diode (LED) photopolymerized gelatin methacryloyl hydrogels (GelMA), encapsulated with stem cells from the apical papilla (SCAP) and human umbilical vein endothelial cells (HUVECs), in promoting vasculature network formation as a function of hydrogel physical and mechanical properties, as well as total cell density. Lithium acylphosphinate (LAP) was used as the photoinitiator in concentrations of 0.05, 0.075, 0.1% (w/v). GelMA hydrogel precursors of 5% (w/v) were encapsulated with cocultures of SCAPs and HUVECs at different cell densities (1×, 5×, and 10 × 106 cells/mL) and photo-cross-linked for 5 s. Results suggested that the compressive modulus of GelMA hydrogels increased as a function of LAP concentration, and had a maximum stiffness of 3.2 kPa. GelMA hydrogels photopolymerized using 0.05 or 0.075% LAP, which had an average of 1.5 and 1.6 kPa of elastic modulus respectively, had the most efficient vasculature formation after 5 days, and these results were further enhanced when the highest cell density (10 × 106 cells/mL) was used. Immunofluorescence images showed that SCAP cells spread in close contact with endothelial networks and expressed alpha smooth muscle actin (αSMA), which is suggestive of their differentiation into pericyte-like cells. αSMA expression was also apparently higher in hydrogels polymerized with 0.05% LAP and 10 × 106 cells/mLl. In conclusion, photopolymerization of GelMA hydrogels using an LED-light source can be an effective method for potential chair-side/in situ procedures for engineering of vascularized tissue constructs in regenerative medicine.

Endothelial cell functions impaired by interferon in vitro: Insights into the molecular mechanism of thrombotic microangiopathy associated with interferon therapy

IntroductionInterferon (IFN)-α and IFN-β approved for treatment of chronic hepatitis C viral infection and multiple sclerosis respectively have been linked to thrombotic microangiopathy (TMA) affecting renal function. Since the molecular mechanisms underlying this severe complication remain largely unclear, we aimed to investigate whether IFN affects directly in vitro endothelial cell functions associated with angiogenesis and blood haemostasis, as well as endothelial cell-derived vasodilators of nitric oxide (NO) and prostacyclin. MethodsProliferation and survival of human umbilical vein endothelial cells (HUVECs) were measured by BrdU incorporation and alamarBlue assays. Angiogenesis was evaluated in co-cultures of HUVECs and human dermal fibroblasts. Fibrinolysis molecules were measured with ELISA. NO and prostacyclin were measured using a fluorescent NO-specific probe and a competitive enzyme immunoassay, respectively. ResultsHUVEC proliferation was dose-dependently inhibited by IFN-β1a and IFN-β1b, but not by IFN-α2a and IFN-α2b. Consistently, IFN-β1a and IFN-β1b also reduced survival of HUVECs, but this again was not observed with IFN-α. However, both IFN subtypes inhibited VEGF-induced development of capillary-like structures, but the effect of IFN-α was less potent than IFN-β. In addition, both IFN subtypes upregulated interferon inducible protein 10 production from treated co-cultures while suppressing angiogenesis. Furthermore, intracellular NO generation was reduced by IFN-α2a and IFN-β1a, whereas prostacyclin release from HUVECs was not affected by IFN. Importantly, both IFN-β1a- and IFN-β1b-treated HUVECs showed a marked reduction in urokinase-type plasminogen activator release and a much greater secretion of plasminogen activator inhibitor-1 than tissue-type plasminogen activator compared with untreated cells, suggesting decreased fibrinolytic activity. IFN-α, however was less effective in modulating the fibrinolysis system. ConclusionsWe demonstrate the detrimental effects of IFN on endothelial cell functions mediated with angiogenesis and fibrinolysis, which could potentially cause the loss of physiological endothelium thromboresistance and facilitate the development of vascular complications in a clinical setting. Mechanistically, our findings have implications for understanding how IFN therapy can foster the development of TMA.

Inhibition of angiogenesis by leflunomide via targeting the soluble ephrin-A1/EphA2 system in bladder cancer

Angiogenesis plays an important role in bladder cancer (BCa). The immunosuppressive drug leflunomide has attracted worldwide attention. However, the effects of leflunomide on angiogenesis in cancer remain unclear. Here, we report the increased expression of soluble ephrin-A1 (sEphrin-A1) in supernatants of BCa cell lines (RT4, T24, and TCCSUP) co-cultured with human umbilical vein endothelial cells (HUVECs) compared with that in immortalized uroepithelial cells (SV-HUC-1) co-cultured with HUVECs. sEphrin-A1 is released from BCa cells as a monomeric protein that is a functional form of the ligand. The co-culture supernatants containing sEphrin-A1 caused the internalization and down-regulation of EphA2 on endothelial cells and dramatic functional activation of HUVECs. This sEphrin-A1/EphA2 system is mainly functional in regulating angiogenesis in BCa tissue. We showed that leflunomide (LEF) inhibited angiogenesis in a N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced bladder carcinogenesis model and a tumor xenograft model, as well as in BCa cell and HUVEC co-culture systems, via significant inhibition of the sEphrin-A1/EphA2 system. Ephrin-A1 overexpression could partially reverse LEF-induced suppression of angiogenesis and subsequent tumor growth inhibition. Thus, LEF has a significant anti-angiogenesis effect on BCa cells and BCa tissue via its inhibition of the functional angiogenic sEphrin-A1/EphA2 system and may have potential for treating BCa beyond immunosuppressive therapy.

The role of vascular endothelial growth factor and mesenchymal stem cells during angiogenesis

Objective: Angiogenesis is essential for bone remodeling and regeneration. We previously showed that 3 months after transplantation of mesenchymal stem cells (MSCs) into a bone defect area, significantly more regenerated bone was present on the MSC side than on the control side. On the side transplanted with MSCs, the number of blood vessels was significantly higher. Therefore, during the remodeling process, MSCs, which are necessary for regenerating bone, were involved in bone regeneration through angiogenesis in the transplanted area. In addition, MSCs produce Vascular Endothelial Growth Factor (VEGF). Therefore, we investigated the influence of differentiation of MSCs on the expression of VEGF. Methods: We investigated how changes in osteogenic differentiation of MSCs affect VEGF gene and protein expression and how co-culture with Human Umbilical Vein Endothelial Cells (HUVECs) affects gene expression in MSCs. We also determined the role MSCs play in the transplanted area, and the effects on HUVEC morphology when co-cultured with MSCs. Results: VEGF gene and protein expression in undifferentiated MSCs was higher than in differentiated MSCs. VEGF gene expression in MSCs co-cultured with HUVECs was higher than when MSCs were cultured alone. In co-cultures of MSCs and HUVECs, a lumen-like structure was observed on the 3rd day of culture, and then several luminal structures were observed later. Conclusion: MSC transplantation may contribute to angiogenesis via production of VEGF.

Peptide-Functionalized Polyurethane Coatings Prepared via Grafting-To Strategy to Selectively Promote Endothelialization.

Endothelialization, formation of endothelial cells (ECs) layer on cardiovascular implant surface, is considered an ideal approach to prevent restenosis (renarrowing of blood vessel mainly due to the accumulation of proliferated vascular smooth muscle cells, SMCs) and thrombosis. In this study, the possibility of using polyurethane (PU) as a coating platform for functionalization with peptide to enhance endothelialization on implants is explored. PUs are synthesized through metal-free organocatalytic polymerization followed by chemical conjugation with an EC-specific REDV peptide through thiol-ene reaction. Meanwhile, the free isocyanate groups of PU allow for covalent grafting of REDV-functionalized PU (PU/REDV) to silanize implant materials (nitinol and PET). PU/REDV coating with peptide grafting density of ≈2 nmol cm-2 selectively accommodates primary human umbilical vein ECs (HUVECs) and retards spreading of primary human umbilical artery SMCs (HUASMCs). In addition, a layer of HUVECs is formed within 3 d on PU/REDV-coated surfaces, while proliferation of HUASMCs is inhibited. The selectivity is further confirmed by coculture of HUVECs and HUASMCs. Moreover, the PU/REDV-coated surfaces are less thrombogenic as evidenced by reduced number and activity of adhered platelets. Therefore, PU/REDV can be potentially used as a coating of cardiovascular implants to prevent restenosis and thrombosis by promoting endothelialization.

Effects of Co-Culture Media on Hepatic Differentiation of hiPSC with or without HUVEC Co-Culture.

The derivation of hepatocytes from human induced pluripotent stem cells (hiPSC) is of great interest for applications in pharmacological research. However, full maturation of hiPSC-derived hepatocytes has not yet been achieved in vitro. To improve hepatic differentiation, co-cultivation of hiPSC with human umbilical vein endothelial cells (HUVEC) during hepatic differentiation was investigated in this study. In the first step, different culture media variations based on hepatocyte culture medium (HCM) were tested in HUVEC mono-cultures to establish a suitable culture medium for co-culture experiments. Based on the results, two media variants were selected to differentiate hiPSC-derived definitive endodermal (DE) cells into mature hepatocytes with or without HUVEC addition. DE cells differentiated in mono-cultures in the presence of those media variants showed a significant increase (p < 0.05) in secretion of α-fetoprotein and in activities of cytochrome P450 (CYP) isoenzymes CYP2B6 and CYP3A4 as compared with cells differentiated in unmodified HCM used as control. Co-cultivation with HUVEC did not further improve the differentiation outcome. Thus, it can be concluded that the effect of the used medium outweighed the effect of HUVEC co-culture, emphasizing the importance of the culture medium composition for hiPSC differentiation.

Abstract 1: Galectins in glioblastoma: opportunities for combined therapy

Abstract Background: Despite aggressive treatment, including surgical resection, radiation and chemotherapy, over 90% of glioblastoma (GB) patients experience tumor recurrence. This may be due to high migratory potential, angiogenesis, molecular heterogeneity and a strong immunosuppressive environment. GB expresses high levels of carbohydrate-binding galectin proteins and histone deacetylase (HDAC) activity. The aim of this study was: 1) identify the differential expressions of galectin 1-15 protein levels in human GB patient samples as compared to normal tissue (obtained from Institutional Tissue Bank) and (2) modulate the galectin functions with and without a HDAC inhibitor (DATS: Dially Triisulfide and SAHA: Suberoylanilide Hydroxamic Acid ) or bevacizumab in in vitro GB models. Methods: The effects of TMZ, ionizing radiation, or combined chemoradiation on galectin protein secretion and expression were assessed in human GB cells and human umbilical vein endothelial cells (HUVECs). Results: We found increased galectin-1 protein expression in human GB tissue. We also observed that HUVEC co-culture with GB cells increased galectin-1 protein expression by 14 - 20% following bevacizumab, and conferred a bevacizumab protective benefit to GB cells. Our in vitro models promisingly demonstrated that 72 hr treatments with 25 µM of galectin 1 inhibitor + HDAC inhibitor induce antitumor activity in GB cells. Western blot and activities assay results also demonstrated that combination blockade of HDAC activity and galectin-1 augmented apoptosis in GB cells, which mechanistically involves activation of caspase-3 and inhibition of anti-apoptotic protein (survivin, p-Akt, and Mcl-1 expression). Conclusion: Our in vitro culture results suggest possible benefit in combining a galectin inhibitor with an HDAC inhibitor in GB. Further studies in different animal models are warranted. Citation Format: David Cachia, Arindam Rano Chatterjee, William Alexander Vandergrift, Sunil J. Patel, Gabriel A. Rabinovich, Arabinda Das. Galectins in glioblastoma: opportunities for combined therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1. doi:10.1158/1538-7445.AM2017-1

The cross talk between cervical carcinoma cells and vascular endothelial cells mediated by IL-27 restrains angiogenesis.

To explore whether cervical carcinoma cell-derived interleukin-27 (IL-27) modulates the angiogenesis of vascular endothelial cells. The expression of IL-27 in cervical cancer tissues and cervical cell lines was analyzed by immunohistochemistry, ELISA and flow cytometry. Then, the effects of IL-27 on the proliferation and apoptosis-related molecules and angiogenesis in vitro of human umbilical vein endothelial cells (HUVECs) were investigated. Finally, in vivo experiment was performed to further confirm the effects of IL-27. Compared with cervicitis, the cervical cancer tissues highly expressed IL-27. Both HeLa and CaSki cells secreted IL-27, and HUVECs expressed low levels of IL-27 receptors (IL-27R). However, the co-culture of cervical cell lines and HUVECs led to a significant elevation of IL-27R on HUVECs. Co-culturing with IL-27-overexpressed HeLa cells downregulated Ki-67 and Bcl-2 and upregulated Fas expression in HUVECs. In addition, overexpression of IL-27 in HeLa cells and CasKi cells secreted less IL-8 and could further restrict angiogenesis compared with control cells in vitro. In the subcutaneous tumorous model of C57/BL6 mouse, there were decreased vessel density and tumor volume when inoculation with IL-27-overexpressed TC-1 cells. This study indicates that IL-27 secreted by cervical carcinoma cells restricts the angiogenesis in a paracrine manner in the pathogenesis of cervical cancer.

Efficacy and safety of aflibercept in in vitro and in vivo models of retinoblastoma.

BackgroundTo evaluate the inhibitory effects of aflibercept on the growth and subretinal invasion of retinoblastoma.MethodsXenotransplantation and orthotopic mouse models were created by injecting Y-79 cells subcutaneously and intravitreally, respectively. After induction of retinoblastoma, animals were intraperitoneally injected with aflibercept (25 mg/kg body weight) or saline twice a week for 3 weeks. Tumor size was measured weekly and compared between the two groups. At 4 weeks, animals were sacrificed and an immunohistochemical examination was conducted to compare the microvascular density and degree of apoptosis between groups. In addition, the degree of choroidal invasion was also analyzed in the orthotopic xenotransplantation model. A co-culture system of Y-79 or WERI-Rb-1 cells and human umbilical vein endothelial cells (HUVECs) was used for in vitro experiments, and the anti-angiogenic effect of aflibercept was evaluated by analyzing cell numbers.ResultsIn the Y-79 xenotransplantation model, aflibercept treatment significantly inhibited tumor growth at 4 weeks versus baseline compared with saline-injected mice (188.53 ± 118.53 mm3 vs. 747.87 ± 118.83 mm3, respectively, P < 0.001). Tumors isolated from aflibercept-treated mice contained fewer blood vessels (8.59 % ± 7.60 % vs. 14.91 % ± 4.53 %, respectively, P < 0.05) and an increased number of apoptotic cells (15.10 ± 9.13 vs. 4.44 ± 2.24, respectively, P < 0.05). In the orthotopic model, the degree of subretinal invasion of tumor cells was significantly reduced after aflibercept treatment (0.07 ± 0.06 vs. 0.15 ± 0.10, P < 0.05). And addition of aflibercept to co-cultures of HUVECs and Y-79, WERI-Rb-1 cells significantly reduced HUVEC proliferation.ConclusionsAflibercept reduced retinoblastoma angiogenesis in association with a significant reduction in tumor growth and invasion. These findings suggest that aflibercept could be used in an adjuvant role together with systemic chemotherapy to reduce tumor size and angiogenesis in retinoblastoma.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-016-0451-7) contains supplementary material, which is available to authorized users.

Transfer of microRNA-486-5p from human endothelial colony forming cell–derived exosomes reduces ischemic kidney injury

Administration of human cord blood endothelial colony-forming cells (ECFCs) or their exosomes protects mice against kidney ischemia/reperfusion injury. Here we studied the microRNA (miRNA) content of ECFC exosomes and the role of miRNA transfer in kidney and endothelial cell protection. ECFC exosomes were enriched in miR-486-5p, which targets the phosphatase and tensin homolog (PTEN) and the Akt pathway. In cultured endothelial cells exposed to hypoxia, incubation with ECFC exosomes increased miR-486-5p, decreased PTEN, and stimulated Aktphosphorylation. Exposure of hypoxic endothelial cellsto conditioned medium from ECFCs pretreated with anti-miR-486-5p blocked increases in miR-486-5p and phosphorylated Akt, restored expression of PTEN, and enhanced apoptosis. Coculture of endothelial cells with ECFCs enhanced endothelial miR-486-5p levels. Targeting of PTEN by miR-486-5p was observed in endothelial cells, and PTEN knockdown blocked apoptosis. In mice with ischemic kidney injury, infusion of ECFC exosomes induced potent functional and histologic protection, associated with increased kidney miR-486-5p levels, decreased PTEN, and activation of Akt. Infusion of exosomes from ECFCs transfected with anti-miR-486-5p had no protective effect. Thus, delivery of ECFC exosomes reduces ischemic kidney injury via transfer of miR-486-5p targeting PTEN. Exosomes enriched in miR-486-5p could represent a therapeutic tool in acute kidney injury.

Conditioned medium from human umbilical vein endothelial cells markedly improves the proliferation and differentiation of circulating endothelial progenitors

Circulating endothelial progenitor cells (EPCs) have been suggested as a precious source for generating functionally competent endothelial cells (ECs), candidate for various clinical applications. However, the paucity of these progenitor cells and the technical difficulties for their in vitro growth represent a main limitation to their use. In the present study we hypothesized that the paracrine effects of human umbilical vein endothelial cells (HUVECs) may improve endothelial cell generation from cord blood (CB) EPCs. In line with this hypothesis we showed that HUVEC conditioned medium (CM) or co-culture with HUVECs markedly improved the proliferation and differentiation and delayed the senescence of CB EPCs.The endothelial-promoting effect of CM seems to be related to smaller vesicles including exosomes (sEV/exo) contained in this medium and transferred to CB CD34+ EPCs: in fact, purified preparations of sEV/exo isolated from CM mimicked the effect of CM to sustain endothelial formation. These observations provided the interesting indication that mature ECs exert a stimulatory effect on endothelial cell differentiation from CD34+ cells.

Cultures and co-cultures of human blood mononuclear cells and endothelial cells for the biocompatibility assessment of surface modified AISI 316L austenitic stainless steel

Samples of AISI 316L austenitic stainless steel were subjected either to grinding and polishing procedure, or to grinding and then low temperature glow-discharge nitriding treatment, or to grinding, nitriding and subsequently coating with collagen-I. Nitrided samples, even if only ground, show a higher corrosion resistance in PBS solution, in comparison with ground and polished AISI 316L. Biocompatibility was evaluated in vitro by incubating the samples with either peripheral blood mononuclear cells (PBMC) or human umbilical vein endothelial cells (HUVEC), tested separately or in co-culture. HUVEC-PBMC co-culture and co-incubation of HUVEC with PBMC culture medium, after the previous incubation of PBMC with metallic samples, allowed to determine whether the incubation of PBMC with the different samples might affect HUVEC behaviour. Many biological parameters were considered: cell proliferation, release of cytokines, matrix metalloproteinases (MMPs) and sICAM-1, gelatinolytic activity of MMPs, and ICAM-1 protein expression. Nitriding treatment, with or without collagen coating of the samples, is able to ameliorate some of the biological parameters taken into account. The obtained results point out that biocompatibility may be successfully tested in vitro, using cultures of normal human cells, as blood and endothelial cells, but more than one cell line should be used, separately or in co-culture, and different parameters should be determined, in particular those correlated with inflammatory phenomena.

EphrinB2 Stabilizes Vascularlike Structures Generated by Endothelial Cells and Stem Cells from Apical Papilla

IntroductionThis study aimed to investigate the roles of ephrinB2 in stabilizing vascularlike structures generated by stem cells from apical papilla (SCAPs) and human umbilical vein endothelial cells (HUVECs). MethodsHUVECs were seeded alone or with SCAPs concurrently or 12 hours later. Angiogenesis and ephrinB2 phosphorylation were assayed at different time points. Additionally, ephrinB2 expression in SCAPs and HUVECs was silenced with small interfering RNA, and vascularlike structure formation within coculture was assessed; 1 × 105 HUVECs were seeded in transwell inserts, and 6 × 105 SCAPs were plated in lower wells with or without ephrinB2-Fc. Migratory cells were stained and counted. Delayed addition of ephrinB2-Fc to the coculture of HUVECs and SCAPs was performed to evaluate the role of ephrinB2 on the stabilization of vascularlike structures. ResultsConcurrent coculture of SCAPs and HUVECs yielded significantly longer tubule lengths at 4, 8, and 12 hours (P < .05). Delayed addition of SCAPs to coculture with HUVECs resulted in vascularlike structures persisting longer than the HUVEC monoculture. Western blot confirmed that ephrinB2 phosphorylation was initiated at 0.5 hours of coculture and peaked at 1 hour. Silencing ephrinB2 expression in SCAPs and HUVECs resulted in the absence of vascularlike structures. Enhanced migration of HUVECs by SCAPs could be inhibited by ephrinB2-Fc. When ephrinB2-Fc was added at 3 hours of coculture, the vascularlike structures were stabilized for more than 12 hours as compared with 9 hours in the control group. ConclusionsEphrinB2 plays an important role in the stabilization of vascularlike structures generated by HUVECs and SCAPs.

Renal cell carcinoma alters endothelial receptor expression responsible for leukocyte adhesion.

Renal cell carcinoma (RCC) escapes immune recognition. To elaborate the escape strategy the influence of RCC cells on endothelial receptor expression and endothelial leukocyte adhesion was evaluated. Human umbilical vein endothelial cells (HUVEC) were co-cultured with the RCC cell line, Caki-1, with and without tumor necrosis factor (TNF)-alpha. Intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial (E)-selectin, standard and variants (V) of CD44 were then analysed in HUVEC, using flow cytometry and Western blot analysis. To determine which components are responsible for HUVEC-Caki-1 interaction causing receptor alteration, Caki-1 membrane fragments versus cell culture supernatant were applied to HUVECS. Adhesion of peripheral blood lymphocytes (PBL) and polymorphonuclear neutrophils (PMN) to endothelium was evaluated by co-culture adhesion assays. Relevance of endothelial receptor expression for adhesion to endothelium was determined by receptor blockage. Co-culture of RCC and HUVECs resulted in a significant increase in endothelial ICAM-1, VCAM-1, E-selectin, CD44 V3 and V7 expression. Previous stimulation of HUVECs with TNF-alpha and co-cultivation with Caki-1 resulted in further elevation of endothelial CD44 V3 and V7 expression, whereas ICAM-1, VCAM-1 and E-selectin expression were significantly diminished. Since Caki-1 membrane fragments also caused these alterations, but cell culture supernatant did not, cell-cell contact may be responsible for this process. Blocking ICAM-1, VCAM-1, E-selectin or CD44 with respective antibodies led to a significant decrease in PBL and PMN adhesion to endothelium. Thus, exposing HUVEC to Caki-1 results in significant alteration of endothelial receptor expression and subsequent endothelial attachment of PBL and PMN.

The angiogenic variation of skeletal site-specific human BMSCs from same alveolar cleft patients: a comparative study

Tissue engineering strategies hold great potential for alveolar cleft reconstruction. Bone marrow stromal cells (BMSCs) from iliac crest and craniofacial regions are candidate seeding cells with site-specific characteristics and bone-repairing properties. Craniofacial BMSCs seem to possess stronger multipotency and osteogenic capabilities than BMSCs isolated from iliac crest. However, the angiogenic capabilities of these two type cell is rarely reported. We obtained human BMSCs (hBMSCs) of maxilla (M-hBMSCs) and iliac crest (I-hBMSCs) from same alveolar cleft patients to investigate the agiogenic variations using co-culture system with human umbilical vein endothelial cells (HUVECs). From in vitro comparison, M-hBMSCs allowed HUVECs to form more tube-like structures and sprouting angiogenesis by tube formation assays and 3D fibrin vasculogenic assay, respectively. By transplantation in vivo, M-hBMSCs enhanced larger size vessel like structures distributed the entire implants compared with I-hBMSCs. Western blotting was used to assess the angiogenesis related factors including hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). The results showed a significant higher expression of bFGF protein in M-hBMSCs and HUVECs co-culture system both in vitro and in vivo. As bFGF could promote migration and proliferation of endothelial cells, scratch wound healing and transwell migration assays were performed as well as MTT assays and cell cycle analysis. The data suggested the effect of M-hBMSCs on HUVECs was stronger than I-hBMSCs. Taken together, these results indicated that craniofacial BMSCs seemed to have greater angiogenesis capability than iliac crest BMSCs and this might be associated with the different levels of bFGF protein expression in co-culture system.

Dual Role of Mesenchymal Stem Cells Allows for Microvascularized Bone Tissue-Like Environments in PEG Hydrogels.

In vitro engineered tissues which recapitulate functional and morphological properties of bone marrow and bone tissue will be desirable to study bone regeneration under fully controlled conditions. Among the key players in the initial phase of bone regeneration are mesenchymal stem cells (MSCs) and endothelial cells (ECs) that are in close contact in many tissues. Additionally, the generation of tissue constructs for in vivo transplantations has included the use of ECs since insufficient vascularization is one of the bottlenecks in (bone) tissue engineering. Here, 3D cocultures of human bone marrow derived MSCs (hBM-MSCs) and human umbilical vein endothelial cells (HUVECs) in synthetic biomimetic poly(ethylene glycol) (PEG)-based matrices are directed toward vascularized bone mimicking tissue constructs. In this environment, bone morphogenetic protein-2 (BMP-2) or fibroblast growth factor-2 (FGF-2) promotes the formation of vascular networks. However, while osteogenic differentiation is achieved with BMP-2, the treatment with FGF-2 suppressed osteogenic differentiation. Thus, this study shows that cocultures of hBM-MSCs and HUVECs in biological inert PEG matrices can be directed toward bone and bone marrow-like 3D tissue constructs.

Endothelial Rac1 is essential for hematogenous metastasis to the lung.

A variety of vasoactive stimuli induce endothelial permeability through Rac1, a membrane of Rho small GTPases. Here, we determine whether tumor-secreted vasoactive stimulant through Rac1 inducing permeability contributes to hematogenous metastasis. Activation of Rac1 was assayed in human umbilical vein endothelial cells (HUVEC), transendothelial passages were measured by Transwell chambers, and hematogenously metastatic mouse model was generated by intravenous injection with Lewis lung carcinoma cells (LLC). LLC secreted abundant vascular endothelial growth factor (VEGF) in the culture media and sera of mice bearing LLC xenografts or metastatic LLC, and VEGF activated Rac1 through VEGF receptors/PI3Kβ signaling cascade, resulting in hyperoxidative stress and consequent hyperpermeability in HUVEC. Moreover, in co-culture of LLC and HUVEC, significant increases in endothelial permeability and transendothelial migration of LLC were robustly attenuated by either anti-VEGF neutralizing antibody or Rac1 knockdown in HUVEC. Finally, in metastatic mouse model, deletion of one copy of Rac1 in endothelium not only significantly attenuated LLC-induced vascular permeability, but robustly reduced the metastasis of LLC to lungs. This study supports that tumor-secreted vasoactive stimuli activate Rac1 to induce permeability and consequent transendothelial migration of tumor cells, and that loss of Rac1 function in endothelium is an effective therapeutic intervention for hematogenous metastasis.

Combined temozolomide and ionizing radiation induces galectin-1 and galectin-3 expression in a model of human glioma

AbstractBackground Despite aggressive treatment for glioblastoma multiforme (GBM), including surgical resection, radiotherapy and temozolomide (TMZ) chemotherapy, over 90% of patients experience tumor recurrence. Galectins are carbohydrate-binding proteins that are overexpressed in the stroma of GBM tumors, and are potent modulators of GBM cell migration and angiogenesis. The objective of this study was to analyze glioma and endothelial cell galectin expression in response to combined chemoradiation. Methodology The effects of TMZ, ionizing radiation, or combined chemoradiation on galectin protein secretion and expression were assessed in U87 orthotopically grown GBM tumors in mice, as well as in vitro in U87 human glioma cells and human umbilical vein endothelial cells (HUVECs). Results We found that combination chemoradiation increased galectin-1 and galectin-3 protein expression in U87 glioma cells. In response to radiation alone, U87 cells secreted significant levels of galectin-1 and galectin-3 into the microenvironment. HUVEC co-culture increased U87 galectin-1 and galectin-3 protein expression 14 - 20% following chemoradiation, and conferred a radioprotective benefit to U87 glioma cells. In vivo, radiation alone and combination chemoradiation significantly increased tumor galectin-1 expression in an orthotopic murine model of GBM. Conclusions Glioma cell galectin expression increased following combined chemoradiation, both in vitro and in vivo. The presence of endothelial cells further increased glioma cell galectin expression and survival, suggesting that crosstalk between tumor and endothelial cells in response to standard chemoradiation may be an important factor in mediating glioma recurrence, potentially via galectin upregulation.