Capillary-like Tube Formation Research Articles

The Hypoxia-Selective Epigenetic Agent, Rrx-001, Triggers Apoptosis and Overcomes Drug-Resistance in Multiple Myeloma Cells

Introduction The bone marrow (BM) microenvironment confers growth, survival, and drug resistance in multiple myeloma (MM) cells (Chauhan et al, Cancer Cell 2009, 16:309-323) BM hypoxia (low oxygenation) plays a role in promoting MM cell survival, drug resistance, migration, and metastasis. Novel therapies that selectively target the MM cell in its hypoxic BM milieu may therefore overcome conventional drug resistance. Recent studies led to the development of a novel aerospace industry-derived Phase 2 molecule RRx-001 with hypoxia-selective epigenetic and NO-donating properties. A Phase I clinical trial demonstrated promising evidence of anti-tumor activity in a heavily pretreated population with no dose-limiting toxicities (Reid et al. J Clin Oncol 32:5s, 2014 suppl; abstr 2578, Reid et al, Lancet Oncology, in press). RRx-001 is currently under investigation in multiple Phase II clinical trials. Here we examined both the mechanism of action and anti-MM activity of RRx-001 using in vitro and in vivo models of MM.Methods Cell viability, apoptosis, and migration assays were performed using MTT, Annexin V staining, and transwell Inserts, respectively. ROS and NO generation was measured as previously described (Chauhan et al., Blood, 2004, 104:2458). Synergistic anti-MM activity was assessed by isobologram analysisusing "CalcuSyn" software program. In vitro angiogenesis was assessed using matrigel capillary-like tube formation assays. DNMT1 activity was measured using DNMT1 assay kit. USP7 siRNA was purchased from Dharmacon. CB-17 SCID-mice were subcutaneously inoculated with MM.1S cells as previously described (Chauhan et al., Cancer Cell 2012, 11:345-358). Statistical significance of data was determined using a Student's t test. RRx-001 was obtained from EpicentRx, CA, USA; USP7 inhibitor P5091, bortezomib, SAHA, and pomalidomide were purchased from Selleck chemicals, USA.Results Treatment of MM cell lines (MM.1S, MM.1R, RPMI-8226, OPM2, H929, Dox-40 ARP-1, KMS-11, ANBL6.WT, ANBL6.BR, and LR5) and primary patient cells for 48h significantly decreased their viability (IC50 range 1.25nM to 2.5nM) (p < 0.05; n=3) without markedly affecting PBMCs from normal healthy donors, suggesting specific anti-MM activity and a favorable therapeutic index for RRx-001. Tumor cells from 3 of 5 patients were obtained from patients whose disease was progressing while on bortezomib, dexamethasone, and lenalidomide therapies. Moreover, RRx-001 inhibits proliferation of MM cells, even in the presence of BM stromal cells. Washout experiments showed that a short time (3h) exposure of MM cells to RRx-001 triggered irreversible cell death. RRx-001-triggered apoptosis is associated with: 1) induction of DNA damage response signaling via ATM/p53/gH2AX axis; 2) activation of caspases mediating both intrinsic and extrinsic apoptotic pathways; 3) increase in oxidative stress through release of ROS and generation of NO; and 4) decrease in DNMT1 activity and global methylation levels. Furthermore, RRx-001 blocked migration of MM cells and angiogenesis. Deubiqyitylating enzyme USP7 stimulates DNMT1 enzymatic activity. USP7-siRNA reduced DNMT1 activity and decreased MM cell viability. Importantly, the combination of USP7 inhibitor P5091 and RRx-001 triggered synergistic anti-MM activity associated with a robust decrease in DNMT1 activity, as well as increased degradation of USP7 substrate MDM2 and induction of downstream p21/p53 signaling axis. In vivo studies using a subcutaneous human MM xenograft model shows that RRx-001 is well tolerated, inhibits tumor growth, and enhances survival. Finally, combining RRx-001 with pomalidomide, bortezomib or SAHA induces synergistic anti-MM activity in p53-WT and p53-null MM cells, and overcomes drug resistance.Conclusion Our preclinical studies demonstrate that RRx-001, a ROS-mediated epigenetic inhibitor with anti-angiogenic properties selectively targets MM cells in vivo and synergizes with existing anti-MM agents to overcome therapeutic resistance. Our data also suggest a potential mechanism of action for RRx-001-induced epigenetic changes via USP7-DNMT1 complex and downstream p53/p21 signaling cascade. Collectively, these results provide a rationale for rapid translation of RRx-001, either alone or in combination, in a clinical trial of relapsed refractory MM. DisclosuresOronsky:epicentrx: Employment. Scicinski:epicentrx: Employment. Chauhan:Stemline Therapeutics: Consultancy.

Abstract A11: Radio-sensitivities and angiogenic signaling pathway of irradiated endothelial cells isolated from cancer and normal tissue of human breasts in vitro

Abstract Despite the strong possibility that endothelial cells of tumors and normal tissues may be different in various aspects, most of the previous studies on endothelial cells have been conducted using normal endothelial cells. Therefore, we have developed a novel method for harvesting endothelial cells from blood vessels of freshly obtained cancer and adjacent normal tissue of human breast, and further investigated radio-sensitivities and angiogenic signaling pathway in the alternation of angiogenic process observed after the purified cancer-derived endothelial cells (CECs) and normal tissue-derived endothelial cells (NECs) were irradiated in vitro. When human breast tissues including cancer were embedded in Matrigel and cultured in endothelial cell culture medium (ECM) containing growth factors, endothelial cells grew out of the tissues. The endothelial cells were harvested, cultured as monolayer cells in plates coated with gelatin, and exposed to radiation, and then the changes in clonogenic cell survival, tube formation capacity, γH2AX foci, gene expression, and cellular signaling pathways were determined. Both CECs and NECs expressed almost the same levels of surface markers CD31, CD105 and TEM-8 (tumor endothelial marker-8), which are known to be expressed in angiogenic endothelial cells, i.e., mitotically active endothelial cells. CECs were significantly more radiosensitive in treatment of single dose (4 Gy) and hyperfractionation (4 Gy in 2 or 4 equal fractions) of ionizing radiation (IR) than their normal counterparts although hyperfractionated IR reduced clonogenic cell death in both NECs and CECs than single dose of IR. In addition, we found that IR-induced foci formation of γH2AX in NECs increased 1 hr and declined afterwards when the cells were treated with 4 Gy of IR. On the contrary, it was remained up to 4 hr in CECs. In NECs, 4 Gy of IR induced an increase in the capillary-like tube formation, the expression of matrix metalloproteinase-2 (MMP-2), and the activation of ERK pathway. However, in CECs, 4 Gy of IR significantly reduced the capillary-like tube formation, and induced the expression of angiostatin and the activation of both AKT and JNK pathways. Additionally, inhibition of ERK with a pharmacological inhibitor or a small interfering RNA markedly suppressed the capillary-like tube formation and the expression of MMP-2 caused by IR in NECs. In CECs, inhibition of either AKT or JNK with a pharmacological inhibitor or a small interfering RNA clearly attenuated inhibition of the capillary-like tube formation, and the expression of angiostatin caused by IR. Furthermore, hypoxia increased the capillary-like tube formation and radioresistance in both NECs and CECs, but the delineation of the mechanisms remains to be studied. We have developed a simple and efficient new method for isolating endothelial cells from cancer and normal tissue. Moreover, our results collectively demonstrate that there are distinct differences in the radiation responses of NECs and CECs, and might provide important clues for improving the efficacy of radiation therapy. [This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (MRC: NRF-2014R1A5A2009392 and NRF-2013M2A2A7043703] Citation Format: Eun-Taex Oh, Min-Jeong Song, Hyemi Lee, Yun-Jeong Choi, Heon Joo Park. Radio-sensitivities and angiogenic signaling pathway of irradiated endothelial cells isolated from cancer and normal tissue of human breasts in vitro. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr A11.

Allicin inhibits lymphangiogenesis through suppressing activation of vascular endothelial growth factor (VEGF) receptor

Allicin, the most abundant organosulfur compound in freshly crushed garlic tissues, has been shown to have various health-promoting effects, including anticancer actions. A better understanding of the effects and mechanisms of allicin on tumorigenesis could facilitate development of allicin or garlic products for cancer prevention. Here we found that allicin inhibited lymphangiogenesis, which is a critical cellular process implicated in tumor metastasis. In primary human lymphatic endothelial cells, allicin at 10μM inhibited capillary-like tube formation and cell migration, and it suppressed phosphorylation of vascular endothelial growth factor receptor 2 and focal adhesion kinase. Using a Matrigel plug assay in mice, addition of 10μg allicin in Matrigel plug inhibited 40–50% of vascular endothelial growth factor-C-induced infiltration of lymphatic endothelial cells and leukocytes. S-Allylmercaptoglutathione, a major cellular metabolite of allicin, had no effect on lymphangiogenic responses in lymphatic endothelial cells. Together, these results demonstrate the antilymphangiogenic effect of allicin in vitro and in vivo, suggesting a novel mechanism for the health-promoting effects of garlic compounds.

Dimethylarginine dimethylaminohydrolase 2 promotes tumor angiogenesis in lung adenocarcinoma.

Although embryonal proteins have been used as tumor marker, most are not useful for detection of early malignancy. In the present study, we developed mouse monoclonal antibodies against fetal lung of miniature swine, and screened them to find an embryonal protein that is produced at the early stage of malignancy, focusing on lung adenocarcinoma. We found an antibody clone that specifically stained stroma of lung adenocarcinoma. LC-MS/MS identified the protein recognized by this clone as dimethylarginine dimethylaminohydrolase 2 (DDAH2), an enzyme known for antiatherosclerotic activity. DDAH2 was found to be expressed in fibroblasts of stroma of malignancies, with higher expression in minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma than in adenocarcinoma in situ (AIS). Moreover, tumors with high stromal expression of DDAH2 had a poorer prognosis than those without. In vitro analysis showed that DDAH2 increases expression of endothelial nitric oxide synthase (eNOS), inducing proliferation and capillary-like tube formation of vascular endothelial cells. In resected human tissues, eNOS also showed higher expression in invasive adenocarcinoma than in AIS and normal lung, similarly to DDAH2. Our data indicate that expression of DDAH2 is associated with invasiveness of lung adenocarcinoma via tumor angiogenesis. DDAH2 expression might be a prognostic factor in lung adenocarcinoma.Electronic supplementary materialThe online version of this article (doi:10.1007/s00428-015-1863-z) contains supplementary material, which is available to authorized users.

Hyaluronan-induced VEGF-C promotes fibrosis-induced lymphangiogenesis via Toll-like receptor 4-dependent signal pathway

Hyaluronan (HA), a component of the extracellular matrix, modulates cellular behavior including angiogenesis. However, little is known about the effect of HA on lymphangiogenesis in fibrosis model. In this study, we investigated the roles of HA in lymphangiogenesis of unilateral ureteral obstruction (UUO). We found that HA cooperated synergistically with vascular endothelial cell growth factor-C to stimulate capillary-like tube formation and increase migration of cells in a haptotaxis assay. Accumulation of HA in the cortical interstitial space was positively correlated with the number of lymphatic vessels after UUO. Depletion of macrophages with clodronate decreased UUO-induced HA accumulation and lymphangiogenesis. Additionally, hyaluronan synthase (HAS) mRNA expression and HA production were increased in bone marrow-derived macrophages upon stimulation with TGF-β1. Transfer of mHAS2 and mHAS3 knock-down CD11b-positive macrophages to SCID mice resulted in a partial decrease in UUO-induced lymphangiogenesis. HA increased expression of vascular endothelial cell growth factor-C in macrophages. Vascular endothelial cell growth factor-C expression and LYVE-1-positive lymphatic area was significantly lower in the UUO-kidney from TLR4 null mice than that from TLR4 wild-type mice. Collectively, these results suggest that HA increases lymphangiogenesis in renal fibrosis model and also stimulates vascular endothelial cell growth factor-C production from macrophages through Toll-like receptor 4-dependent signal pathway.

Fibroblast growth factor-2 did not restore plasminogen system activity in endothelial cells on glycated collagen

People with diabetes experience morbidity and mortality from unregulated microvascular remodeling, which may be linked to hyperglycemia. Elevated glucose leads to extracellular matrix collagen glycation, which delays endothelial capillary-like tube formation in vitro. Glucose also increases endothelial cell fibroblast growth factor-2 (FGF-2) release and extracellular matrix storage, which should increase tube formation. In this study, we determined if FGF-2 could restore plasminogen system activity and angiogenic function in endothelial cells on glycated collagen. Human umbilical vein endothelial cells cultured on native or glycated collagen substrates were stimulated with FGF-2. Plasminogen system activity, cell migration, and capillary-like tube formation were measured, along with plasminogen system protein and mRNA levels. Glycated collagen decreased endothelial cell plasminogen system activity, cell migration, and tube length. FGF-2 did not restore plasminogen system activity or tube formation in cells on glycated collagen, despite decreasing plasminogen activator inhibitor-1 (PAI-1) protein level. We now show that PAI-1 binds to glycated collagen, which may localize PAI-1 to the extracellular matrix. These data suggest that FGF-2 may not restore angiogenic functions in endothelial cells on glycated collagen due to PAI-1 bound to glycated collagen.

Hypoxia-induced fibroblast growth factor 11 stimulates capillary-like endothelial tube formation.

Low oxygen or hypoxia can be observed in the central region of solid tumors. Hypoxia is a strong stimulus for new blood vessel formation or angiogenesis, which is essential for tumor growth and progression. Fibroblast growth factor11 (FGF11) is an intracellular non-secretory FGF whose function has not yet been fully characterized. In the present study, we demonstrated that FGF11 expression is upregulated under hypoxic conditions in human umbilical vein endothelial cells (HUVECs). FGF11 overexpression stimulated capillary-like tube formation, yet did not affect cell migration. Notably, FGF11 markedly increased the levels of tight junction proteins including occludin, zonula occludens-1 (ZO-1) and claudin-5 in HUVECs. The FGF11 promoter contains hypoxia response elements (HREs), and hypoxia-inducible factor-1 (HIF-1) binds to HREs to activate hypoxia-related genes. We demonstrated that hypoxia or HIF-1 expression under normoxic conditions increased the luciferase activity driven by the FGF11 promoter. However, deletion of the HREs from the FGF11 promoter rendered reporter gene activity unresponsive to hypoxia or HIF-1. Taken together, we propose that FGF11 may be involved in the stabilization of capillary-like tube structures associated with angiogenesis and may act as a modulator of hypoxia-induced pathological processes such as tumorigenesis.

Imidazole-based alkaloid derivative LCB54-0009 suppresses ocular angiogenesis and lymphangiogenesis in models of experimental retinopathy and corneal neovascularization.

Abnormally induced angiogenesis and lymphangiogenesis are associated with human diseases, including neovascular eye disease. Substances that inhibit these processes may have potential as an attractive therapeutic strategy for these diseases. In vitro and in vivo angiogenesis and/or lymphangiogenesis were assessed in VEGF- or hypoxia-stimulated endothelial and retinal cells and in animal models of oxygen-induced retinopathy (OIR), streptozotocin-induced diabetic retinopathy (SIDR), suture-induced inflammatory corneal neovascularization (SICNV) and silver nitrate-induced corneal neovascularization. HUVECs and retinal cells were cultured under hypoxic conditions or incubated with VEGF to identify the molecular mechanisms involved. The imidazole-based alkaloid derivative LCB54-0009 inhibited capillary-like tube formation in VEGF-induced HUVECs without inducing cytotoxic effects. Intravitreal injection of LCB54-0009 into retinas suppressed the formation of the pathological neovascular tufts and increased vascular permeability in both OIR of mice and SIDR of rats. Furthermore, subconjunctival injection of LCB54-0009 into the cornea suppressed corneal inflammation and inflammation-associated angiogenesis and lymphangiogenesis in SICNV of mice and silver nitrate cauterization of rats. These pharmacological activities were associated with effects on HIF-1α protein stability and HIF-1α/NF-κB redox sensitivity through its antioxidant activities. LCB54-0009 also inhibited the hypoxia-induced expression of angiopoietin-2, and VEGF-induced VEGFR-2 activation and downstream signalling, resulting in the down-regulation of the expression of pro-angiogenic factors and pro-inflammatory mediators and an up-regulation of the expression of anti-angiogenic factors. LCB54-0009 is a potential candidate molecule for blocking pathological angiogenesis and lymphangiogenesis mediated by HIF-1α- angiopoietin-2 expression and VEGFR-2 activation.

CPU-12, a novel synthesized oxazolo[5,4-d]pyrimidine derivative, showed superior anti-angiogenic activity

Angiogenesis is a crucial requirement for malignant tumor growth, progression and metastasis. Tumor-derived factors stimulate formation of new blood vessels which actively support tumor growth and spread. Various of drugs have been applied to inhibit tumor angiogenesis. CPU-12, 4-chloro-N-(4-((2-(4-methoxyphenyl)-5-methyloxazolo[5,4-d] pyrimidin-7-yl)amino)phenyl)benzamide, is a novel oxazolo[5,4-d]pyrimidine derivative that showed potent activity in inhibiting VEGF-induced angiogenesis in vitro and ex-vivo. In cell toxicity experiments, CPU-12 significantly inhibited the human umbilical vein endothelial cell (HUVEC) proliferation in a dose-dependent manner with a low IC50 value at 9.30 ± 1.24 μM. In vitro, CPU-12 remarkably inhibited HUVEC's migration, chemotactic invasion and capillary-like tube formation in a dose-dependent manner. In ex-vivo, CPU-12 effectively inhibited new microvessels sprouting from the rat aortic ring. In addition, the downstream signalings of vascular endothelial growth factor receptor-2 (VEGFR-2), including the phosphorylation of PI3K, ERK1/2 and p38 MAPK, were effectively down-regulated by CPU-12. These evidences suggested that angiogenic response via the induction of VEGFR through distinct signal transduction pathways regulating proliferation, migration and tube formation of endothelial cells was significantly inhibited by the novel small molecule compound CPU-12 in vitro and ex-vivo. In conclusion, CPU-12 showed superior anti-angiogenic activity in vitro.

Synthesis and antitumor evaluation of novel hybrids of phenylsulfonylfuroxan and epiandrosterone/dehydroepiandrosterone derivatives

Thirteen novel furoxan-based nitric oxide (NO) releasing hybrids (14a–e, 15a–e, 17b–d) of 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated against the MDA-MB-231, HCC1806, SKOV-3, DU145, and HUVEC cell lines for their in vitro anti-proliferative activity. Most of the compounds displayed potent anti-proliferative effects. Among them, 17c exhibited the best activity with IC50 values of 20–1.4nM against four cell lines (MDA-MB-231, SKOV-3, DU145, and HUVEC), and 1.03μM against a tamoxifen resistant breast cancer cell line (HCC1806). Furthermore, five compounds (14a, 15a, 17b–d) were selected to screen for VEGF inhibitory activity. Compounds 15a, 17b,c showed obviously better activity than 2-Methoxyestradiol (2-ME) on reducing levels of VEGF secreted by MDA-MB-231 cell line. In a Capillary-like Tube Formation Assay, compounds 17b,c exhibited a significant suppression of the tubule formation in the concentration of 1.75nM and 58nM, respectively. The preliminary SAR showed that steroidal scaffolds with a linker in 3-position were favorable moieties to evidently increase the bioactivities of these hybrids. Overall, these results implied that 17c merited to be further investigated as a promising anti-cancer candidate.

Biphasic effect of PTK7 on KDR activity in endothelial cells and angiogenesis

Protein tyrosine kinase 7 (PTK7) is a member of the defective receptor protein tyrosine kinase family which lacks catalytic activity. Expression of PTK7 is increased in various cancers but its role in carcinogenesis is not well understood. We previously showed that disruption of PTK7 function suppresses VEGF-induced angiogenic phenotypes in HUVECs and mice. Here, we investigated molecular mechanisms for modulating VEGF-induced physiological effects by PTK7. Treatment with a high concentration of extracellular domain of PTK7 (soluble PTK7; sPTK7) or knockdown of PTK7 inhibited VEGF-induced phosphorylation of kinase insert domain receptor (KDR) but did not inhibit phosphorylation of fms-related tyrosine kinase 1 (FLT-1) in HUVECs. PTK7, more specifically sPTK7, interacted with KDR but not with FLT-1 in HUVECs and HEK293 cells. In vitro binding assay showed that sPTK7 formed oligomers with the extracellular domain of KDR (sKDR) up to an approximately 1:3 molar ratio, and vice versa. sPTK7 at lower molar ratios than sKDR enhanced the binding of VEGF to sKDR. At the same or higher molar ratios, it reduced the binding of VEGF to sKDR. Increasing concentrations of sPTK7 or increasing levels of PTK7 expression first increased and then decreased VEGF-induced KDR phosphorylation, migration, and capillary-like tube formation of HUVECs, as well as in vivo angiogenesis. Taken together, our data demonstrates that PTK7 regulates the activity of KDR biphasically by inducing oligomerization of KDR molecules at lower concentrations and by surrounding KDR molecules at higher concentrations.

IPP51, a chalcone acting as a microtubule inhibitor with in vivo antitumor activity against bladder carcinoma.

We previously identified 1-(2,4-dimethoxyphenyl)-3-(1-methylindolyl) propenone (IPP51), a new chalcone derivative that is capable of inducing prometaphase arrest and subsequent apoptosis of bladder cancer cells. Here, we demonstrate that IPP51 selectively inhibits proliferation of tumor-derived cells versus normal non-tumor cells. IPP51 interfered with spindle formation and mitotic chromosome alignment. Accumulation of cyclin B1 and mitotic checkpoint proteins Bub1 and BubR1 on chromosomes in IPP51 treated cells indicated the activation of spindle-assembly checkpoint, which is consistent with the mitotic arrest. The antimitotic actions of other chalcones are often associated with microtubule disruption. Indeed, IPP51 inhibited tubulin polymerization in an in vitro assay with purified tubulin. In cells, IPP51 induced an increase in soluble tubulin. Furthermore, IPP51 inhibited in vitro capillary-like tube formation by endothelial cells, indicating that it has anti-angiogenic activity. Molecular docking showed that the indol group of IPP51 can be accommodated in the colchicine binding site of tubulin. This characteristic was confirmed by an in vitro competition assay demonstrating that IPP51 can compete for colchicine binding to soluble tubulin. Finally, in a human bladder xenograft mouse model, IPP51 inhibited tumor growth without signs of toxicity. Altogether, these findings suggest that IPP51 is an attractive new microtubule-targeting agent with potential chemotherapeutic value.

587. MiRNA-92a Is Involved in the Regulation of Adipose-Derived Stromal Cell (ADSC) Angiogenic Properties

Reparative and regenerative processes after tissue damage are strongly dependent on successful restoration of vascular network. Mesenchymal stem/stromal cells (MSC) including ADSC located within the vessel wall and closely interacted with endothelial cells appear to be key regulators of angiogenesis and regeneration in adult tissues. Mechanisms of MSC ability to stimulate blood vessel growth and remodeling are extensively studying during last decades. microRNAs (miRs), small noncoding RNAs that regulate gene expression by binding to target mRNAs reducing their stability and/or inhibiting translation, play an important role in MSC regulation. It was demonstrated that miR-92a expressed in endothelial cells was induced in ischemia and involved in the regulation of angiogenesis and vessel patterning. We studied miR-92a impact in ADSC angiogenic properties regulation.ADSC were isolated from subcutaneous fat tissue of healthy young donors (n=4) and cultured up to 2-3 passages. ADSC phenotype characterized by flow cytometry was CD90+/CD73+/CD105+/CD45-/CD31- for all samples and these cells were capable of adipogenic and osteogenic differentiation. We analyzed miR profile in ADSC using Illumina microarrays and found that miR-92a was one of the highly expressed miRs in all ADSC samples. ADSC transfection by pre-miR-92a or anti-miR-92a led to the coordinated changes of miR-92a well-known target genes expression (integrin alpha 5, ITGA5, and mitogen activated protein kinase, MEK4). ADSC with over-expression of miR-92a completely lost the ability to stimulate capillary-like tube formation by endothelial cells (HUVEC) in vitro compared to ADSC transfected by the control gene. However, transfection of ADSC by anti-miR-92a did not significantly increase their stimulating effect in tube formation assay. As paracrine mechanisms are considered to be the most important for realizing of MSC angiogenic potential, we analyzed gene expression (qRT-PCR) and secretion (Bio-Plex assay and ELISA) of some key angiogenic factors in ADSC. We found that mRNA level of vascular endothelial growth factor (VEGF), angiogenin and leptin was slightly increased in ADSC transfected by anti-miR-92a and this tendency was also observed for VEGF secretion. When miR-92a was over-expressed in ADSC secretion of hepatocyte growth factor (HGF) and angiopoetin-1 by these cells significantly decreased compared to the control cells.We conclude that miR-92a might play an important role in the regulation of ADSC ability to stimulate angiogenesis and key angiogenic factors such as VEGF, HGF and angiopoetin-1 are involved in this process. The underlying mechanisms of miR-92a-mediated direct or indirect effects in ADSC need to be further investigated. Anyway, miR-92a could be considered as a promising target for the modulation of ADSC angiogenic potential.

Anti-angiogenic activity of thienopyridine derivative LCB03-0110 by targeting VEGFR-2 and JAK/STAT3 Signalling.

Vascular endothelial growth factor receptor-2 (VEGFR-2) and Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signalling are important for tumor angiogenesis and metastasis. In this study, we identified (3-(2-(3-(morpholinomethyl)phenyl)thieno[3,2-b]pyridin-7-ylamino)phenol (LCB03-0110) as a potent angiogenesis inhibitor. LCB03-0110 inhibited VEGFR-2 and JAK/STAT3 signalling in primary cultured human endothelial cells and cancer cells. An in vitro kinase assay and molecular modelling revealed that LCB03-0110 inhibited VEGFR-2, c-SRC and TIE-2 kinase activity via preferential binding at the ATP-binding site of their kinases. LCB03-0110 successfully occupied the hydrophobic pocket of VEGFR-2, c-SRC and TIE-2. LCB03-0110 also inhibited hypoxia-induced HIF/STAT3 and EGF- or angiopoietin-induced signalling cascades. In addition, LCB03-0110 inhibited VEGF-induced proliferation, viability, migration and capillary-like tube formation. LCB03-0110 also suppressed the sprouting of endothelial cells in the rat aorta and the formation of new blood vessels in the mouse Matrigel plug assay, but also suppressed pulmonary metastasis and tumor xenograft in mice. Our results suggest that LCB03-0110 is a potential candidate small molecule for blocking angiogenesis mediated by aberrant activation of VEGFR-2 and JAK/STAT3 signalling.

Vascularization of hollow channel-modified porous silk scaffolds with endothelial cells for tissue regeneration

Despite the promise for stem cell-based tissue engineering for regenerative therapy, slow and insufficient vascularization of large tissue constructs negatively impacts the survival and function of these transplanted cells. A combination of channeled porous silk scaffolds and prevascularization with endothelial cells was investigated to test the ability of this tissue engineering strategy to support rapid and extensive vascularization process. We report that hollow channels promote in vitro prevascularization by facilitating endothelial cell growth, VEGF secretion, and capillary-like tube formation. When implanted in vivo, the pre-established vascular networks in the hollow channel scaffolds anastomose with host vessels and exhibit accelerated vascular infiltration throughout the whole tissue construct, which provides timely and sufficient nutrients to ensure the survival of the transplanted stem cells. This tissue engineering strategy can promote the effective application of stem cell-based regeneration to improve future clinical applications.

Inhibition of human vascular endothelial cell migration and capillary-like tube formation by the microtubule-stabilizing agent peloruside A.

Peloruside A is a microtubule-stabilizing agent that is currently under investigation as a potential anticancer agent. Peloruside A binds to a site on β-tubulin that is distinct to that of the taxanes (paclitaxel and docetaxel) and the epothilones. An attractive clinical quality of microtubule-stabilizing agents is their ability to target multiple mechanisms of tumour growth. In addition to inducing tumour cell apoptosis by arresting cells in mitosis, microtubule-stabilizing agents also inhibit angiogenesis, a process needed by tumor cells for growth and metastasis. In this study, the effects of peloruside A on endothelial cell processes important for angiogenesis were assessed in comparison to docetaxel. Both peloruside A and docetaxel potently inhibited the proliferation of human umbilical vein endothelial cells, with IC50 values of 1.4 and 1.7 nM, respectively. Peloruside also potently blocked endothelial cell migration during wound closure and the three-dimensional organization of the endothelial cells into capillary-like tubes. In the wound scratch assay, peloruside A inhibited wound recovery with an IC50 of 6.3 nM after 18 h. Docetaxel was approximately 3-fold more potent than peloruside A. The number of capillary-like tubes that formed after 16 h culture in Matrigel™ was also inhibited in a dose-dependent manner with an IC50 of 4.5 nM. Docetaxel was about 2-fold more potent than peloruside A in preventing tube formation. This inhibition of endothelial cell function occurred at relatively non-cytotoxic concentrations over the 16-18 h incubations for both stabilizing agents, suggesting that anti-angiogenic effects are likely to occur before therapeutically relevant doses begin to inhibit tumor growth or adverse side effects develop.

Paclitaxel impairs adipose stem cell proliferation and differentiation

BackgroundCancer patients with chemotherapy-induced immunosuppression have poor surgical site wound healing. Prior literature supports the use of human adipose–derived stem cell (hASC) lipoinjection to improve wound healing. It has been established that multipotent hASCs facilitate neovascularization, accelerate epithelialization, and quicken wound closure in animal models. Although hASC wound therapy may benefit surgical cancer patients, the chemotherapeutic effects on hASCs are unknown. We hypothesized that paclitaxel, a chemotherapeutic agent, impairs hASC growth, multipotency, and induces apoptosis. MethodshASCs were isolated and harvested from consented, chemotherapy and radiation naive patients. Growth curves, MTT (3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide), and EdU (5-ethynyl-2-deoxyguridine) assays measured cytotoxicity and proliferation. Oil Red O stain, Alizarin Red stain, matrigel tube formation assay, and quantitative polymerase chain reaction analyzed hASC differentiation. Annexin V assay measured apoptosis. Immunostaining and Western blot determined tumor necrosis factor α (TNF-α) expression. ResultshASCs were selectively more sensitive to paclitaxel (0.01–30 μM) than fibroblasts (P < 0.05). After 12 d, paclitaxel caused hASC growth arrest, whereas control hASCs proliferated (P = 0.006). Paclitaxel caused an 80.6% reduction in new DNA synthesis (P < 0.001). Paclitaxel severely inhibited endothelial differentiation and capillary-like tube formation. Differentiation markers, lipoprotein lipase (adipogenic), alkaline phosphatase (osteogenic), CD31, and van Willebrand factor (endothelial), were significantly decreased (all P < 0.05) confirming paclitaxel impaired differentiation. Paclitaxel was also found to induce apoptosis and TNF-α was upregulated in paclitaxel-treated hASCs (P < 0.001). ConclusionsPaclitaxel is more cytotoxic to hASCs than fibroblasts. Paclitaxel inhibits hASC proliferation, differentiation, and induces apoptosis, possibly through the TNF-α pathway. Paclitaxel's severe inhibition of endothelial differentiation indicates neovascularization disruption, possibly causing poor wound healing in cancer patients receiving chemotherapy.

An evaluation of the anti-angiogenic effect of the Korean medicinal formula "Sa-mi-yeon-geon-tang" in vitro and in ovo.

BackgroundAngiogenesis is a general hallmark of cancer; therefore, the inhibition of tumor-derived angiogenesis is considered to be an attractive target in the development of anti-cancer agents. Sa-mi-yeon-geon-tang (SMYGT), a decoction that consists of four natural medicinal products, has been traditionally prescribed in Oriental medicine to treat diverse diseases, including cancer. In the present study, we investigated the anti-angiogenic potential of SMYGT in vitro and in ovo.MethodsThe anti-angiogenic potential of SMYGT was evaluated using conventional in vitro assays with human umbilical vein endothelial cells (HUVECs) and chorioallantoic membrane (CAM) assays with fertilized eggs. The expression changes of pro-angiogenic proteins and intracellular signaling in HUVECs following SMYGT treatment were determined by quantitative polymerase chain reaction, gelatinase zymography, and western blot analysis.ResultsSMYGT efficiently inhibited three-dimensional capillary-like tube formation by HUVECs on extracellular matrix supports, as well as new vessel formation on CAMs. SMYGT inhibited cell adhesion to the extracellular matrix and HUVEC cell invasion through Matrigel without affecting cell proliferation, viability, and motility. These anti-angiogenic effects of SMYGT in HUVECs were related to decreases in the phosphorylation of focal adhesion kinase and the expression of matrix metallopeptidase-2 activity.ConclusionsSMYGT exhibited an anti-angiogenic potential in both in vitro and in ovo experiments, which may partially contribute to its anti-tumor effect in clinical conditions. We suggest that SMYGT may be a promising source material for the development of anti-cancer chemotherapeutics that target angiogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-015-0573-z) contains supplementary material, which is available to authorized users.

Carbon monoxide inhibits sprouting angiogenesis and vascular endothelial growth factor receptor-2 phosphorylation

Carbon monoxide (CO) is a gaseous autacoid known to positively regulate vascular tone; however, its role in angiogenesis is unknown. The aim of this study was to investigate the effect of CO on angiogenesis and vascular endothelial growth factor (VEGF) receptor-2 phosphorylation. Human umbilical vein endothelial cells (HUVECs) were cultured on growth factor-reduced Matrigel and treated with a CO-releasing molecule (CORM-2) or exposed to CO gas (250 ppm). Here, we report the surprising finding that exposure to CO inhibits vascular endothelial growth factor (VEGF)-induced endothelial cell actin reorganisation, cell proliferation, migration and capillary-like tube formation. Similarly, CO suppressed VEGF-mediated phosphorylation of VEGFR-2 at tyrosine residue 1175 and 1214 and basic fibroblast growth factor- (FGF-2) and VEGF-mediated Akt phosphorylation. Consistent with these data, mice exposed to 250 ppm CO (1h/day for 14 days) exhibited a marked decrease in FGF-2-induced Matrigel plug angiogenesis (p<0.05). These data establish a new biological function for CO in angiogenesis and point to a potential therapeutic use for CO as an anti-angiogenic agent in tumour suppression.

Phosphatidylinositol 3-Kinase Class II α-Isoform PI3K-C2α Is Required for Transforming Growth Factor β-induced Smad Signaling in Endothelial Cells

We have recently demonstrated that the PI3K class II-α isoform (PI3K-C2α), which generates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,4-bisphosphates, plays crucial roles in angiogenesis, by analyzing PI3K-C2α knock-out mice. The PI3K-C2α actions are mediated at least in part through its participation in the internalization of VEGF receptor-2 and sphingosine-1-phosphate receptor S1P1 and thereby their signaling on endosomes. TGFβ, which is also an essential angiogenic factor, signals via the serine/threonine kinase receptor complex to induce phosphorylation of Smad2 and Smad3 (Smad2/3). SARA (Smad anchor for receptor activation) protein, which is localized in early endosomes through its FYVE domain, is required for Smad2/3 signaling. In the present study, we showed that PI3K-C2α knockdown nearly completely abolished TGFβ1-induced phosphorylation and nuclear translocation of Smad2/3 in vascular endothelial cells (ECs). PI3K-C2α was necessary for TGFβ-induced increase in phosphatidylinositol 3,4-bisphosphates in the plasma membrane and TGFβ receptor internalization into the SARA-containing early endosomes, but not for phosphatidylinositol 3-phosphate enrichment or localization of SARA in the early endosomes. PI3K-C2α was also required for TGFβ receptor-mediated formation of SARA-Smad2/3 complex. Inhibition of dynamin, which is required for the clathrin-dependent receptor endocytosis, suppressed both TGFβ receptor internalization and Smad2/3 phosphorylation. TGFβ1 stimulated Smad-dependent VEGF-A expression, VEGF receptor-mediated EC migration, and capillary-like tube formation, which were all abolished by either PI3K-C2α knockdown or a dynamin inhibitor. Finally, TGFβ1-induced microvessel formation in Matrigel plugs was greatly attenuated in EC-specific PI3K-C2α-deleted mice. These observations indicate that PI3K-C2α plays the pivotal role in TGFβ receptor endocytosis and thereby Smad2/3 signaling, participating in angiogenic actions of TGFβ.