Mesangial cells are essential for the structure and function of glomeruli, but the mechanisms underlying these roles are not well understood. Here, we performed a single-cell RNA-sequence (RNA-seq) analysis of mouse mesangial cells using the Fluidigm C1 platform. We found that gene expression in individual mesangial cells was tremendously heterogeneous, with mean correlation coefficients of 0.20, and most mesangial genes were actually expressed in only a portion of mesangial cells and are therefore presumably dispensable. In contrast, 1,045 genes were expressed in every single mesangial cell and were considered mesangial cell essential genes. A gene ontology analysis revealed a significant enrichment of genes associated with the endothelium, supporting the inference that mesangial cells function as pericytes. Among 58 endothelium-associated genes, 18 encode proteins that are secreted and may be directly involved in endothelial homeostasis. Importantly, 11 (Angpt2, Anxa5, Axl, Ecm1, Eng, Fn1, Mfge8, Msn, Nrp1, Serpine2, and Sparc) were upregulated, while 2 (Apoe and Fgf1) were downregulated in various glomerulopathies. The enrichment of genes associated with other reported functions of mesangial cells was also found. Furthermore, we identified 173 genes specifically expressed in every mesangial cell in glomeruli from the mesangial cell essential gene list. Finally, based on single mesangial cell RNA-seq results, we found that commonly used glomerular cell type markers, including Fhl2, Igfbp5, Wt1, Tek/Tie2, Kdr/Flk1, Flt1/Vegfr1, and Cd34, are actually not specific. Thus, single mesangial cell RNA-seq analysis has provided insights into the functions and underlying mechanisms of mesangial cells.

OBJECTIVE

Maternal cigarette smoking is reportedly associated with miscarriage, fetal growth restriction and placental abruption, and is paradoxically associated with a decreased risk of developing preeclampsia. In the present study, we investigated the gene expression levels of villous tissues in early gestation. We compared the expression levels of the genes related to angiogenesis and apoptosis in the villous tissues obtained from smoking and non-smoking pregnant women.

METHODS

We collected villous tissue samples from 57 women requesting surgical termination due to non-medical reasons at 6-8 weeks of gestation. The maternal cigarette smoking status was evaluated by the level of serum cotinine and patients were divided into active smokers and non-smokers by the serum cotinine level. The placental levels of VEGFA, PGF, FLT1, HIF1A, TP53, BAX and BCL2 mRNA were quantified by real time PCR.

RESULTS

The gene expression level of PGF and HIF1A in the active smoker group was significantly higher than that in the non-smoker group. We did not observe any significant differences in the VEGFA or FLT1 expression between the groups. In active smoker group, the gene expression levels of TP53 and BAX were significantly higher than those in the non-smoker group. The ratio of BAX/BCL2 mRNA in the active smoker group was significantly higher than that in the non-smoker group.

CONCLUSIONS

Our findings revealed that smoking might affect the placenta during early pregnancy. Maternal cigarette smoking in early pregnancy may be associated with villus hypoxia, which may influence angiogenesis and apoptosis.

Infantile hemangioma (IH) is a common benign tumor. Human umbilical vein endothelial cells (HUVECs) have the potential of stem cells, which has been widely used in vascular endothelial cell experiments. Oral propranolol was first reported to treat hemangioma in 2008. However, the role of propranolol in IH remains unclear. Therefore, in this study, we investigated the effects of propranolol on HUVECs in vitro, to explore the underlying mechanism of propranolol in IH. HUVECs were treated with 0.15, 1.5, and 15 μM of propranolol, and transfected with microRNA-4295 (miR-4295) mimic. Cell viability, migration, and apoptosis were examined using Cell Counting Kit-8, transwell assay, and flow cytometry analysis, respectively. In addition, the expressions and concentrations of miR-4295, vascular endothelial growth factor (VEGF), VEGF-A, FLT1, FLT2, and FOXF1 were assessed using real-time polymerase chain reaction, Western blot assay, and enzyme-linked immunosorbent assay. We found that 15 μM of propranolol decreased HUVEC viability the most. Then, cell migration and the concentrations of VEGF and VEGF-A were reduced, and apoptosis was increased when treated with propranolol. Meanwhile, the expressions of VEGF, VEGF-A, FLT1, FLT2, and FOXF1 were downregulated by propranolol exposure. Further study showed that miR-4295 expression was upregulated in IH tissues, and propranolol treatment downregulated miR-4295 expression in HUVECs. MiR-4295 overexpression alleviated the reductions of viability, migration, and factors expression, as well as the increase of apoptosis. Propranolol suppressed HUVEC viability, migration, the expression of VEGF, VEGF-A, FLT1/2, FOXF1, and promoted apoptosis via downregulation of miR-4295. This study lays a foundation for further study of the effect of propranolol on IH.

BACKGROUND

Primary pulmonary mucoepidermoid carcinoma (PMEC) is an uncommon neoplasm with remarkable resemblance to mucoepidermoid carcinoma of the salivary glands. The latter has been shown to harbor t(11,19) resulting in MECT1-MAML2 fusion, which may be of diagnostic and prognostic values. However, the importance of such feature in PMEC has not been well studied.

METHODS

We detected MAML2 rearrangement using fluorescence in situ hybridization (FISH) in tissue samples from 42 cases of PMEC and 40 of adenosquamous carcinoma (ASC), and the expression of potential downstream targets of MECT1-MAML2, including HES1, FLT1 and NR4A2 with immunohistochemistry (IHC). The findings were then examined regarding the clinicopathological parameters and patient outcomes.

RESULTS

FISH analysis revealed MAML2 rearrangement in 50% of the PMEC cases, and such property was prominent in considerable younger patients (33 versus 60 years; p = 0.001) and restricted to cases of low and intermediate grades. IHC analysis showed that FLT1 and HES1 were expressed at lower level in MAML2 rearranged group than MAML2 non-rearranged group (p<0.001 and p = 0.023, respectively). Survival analysis showed significant correlation between MAML2 rearrangement and overall survival (p = 0.023) or disease-free survival (p = 0.027) as well as correlation between FLT1 and overall survival (p = 0.009).

CONCLUSIONS

MAML2 rearrangement appears frequent in PMEC and specific with this tumor. Both the presence of MAML2 rearrangement and absence of FLT1 tend to confer a favorable clinical outcome. These findings suggest that molecular detection of MAML2 rearrangement combined with FLT1 may be of important clinical value for PMEC.

The roles of angiogenesis in development, health, and disease have been studied extensively; however, the studies related to lymphatic system are limited due to the difficulty in observing colorless lymphatic vessels. But recently, with the improved technique, the relative importance of the lymphatic system is just being revealed. We bred transgenic mice in which lymphatic endothelial cells express GFP (Prox1-GFP) with mice in which vascular endothelial cells express DsRed (Flt1-DsRed) to generate Prox1-GFP/Flt1-DsRed (PGFD) mice. The inherent fluorescence of blood and lymphatic vessels allows for direct visualization of blood and lymphatic vessels in various organs via confocal and two-photon microscopy and the formation, branching, and regression of both vessel types in the same live mouse cornea throughout an experimental time course. PGFD mice were bred with CDh5CreERT2 and VEGFR2lox knockout mice to examine specific knockouts. These studies showed a novel role for vascular endothelial cell VEGFR2 in regulating VEGFC-induced corneal lymphangiogenesis. Conditional deletion of vascular endothelial VEGFR2 abolished VEGFA- and VEGFC-induced corneal lymphangiogenesis. These results demonstrate the potential use of the PGFD mouse as a powerful animal model for studying angiogenesis and lymphangiogenesis.

Etv2 is an essential transcriptional regulator of hematoendothelial lineages during embryogenesis. Although Etv2 downstream targets have been identified, little is known regarding the upstream transcriptional regulation of Etv2 gene expression. In this study, we established a novel methodology that utilizes the differentiating ES cell and embryoid body system to define the modules and enhancers embedded within the Etv2 promoter. Using this system, we defined an autoactivating role for Etv2 that is mediated by two adjacent Ets motifs in the proximal promoter. In addition, we defined the role of VEGF/Flk1-Calcineurin-NFAT signaling cascade in the transcriptional regulation of Etv2. Furthermore, we defined an Etv2-Flt1-Flk1 cascade that serves as a negative feedback mechanism to regulate Etv2 gene expression. To complement and extend these studies, we demonstrated that the Flt1 null embryonic phenotype was partially rescued in the Etv2 conditional knockout background. In summary, these studies define upstream and downstream networks that serve as a transcriptional rheostat to regulate Etv2 gene expression.

We evaluated whether the inhibitory effects of vascular endothelial growth factor (VEGF)-targeted drugs on the proliferation of cancer cells differed according to VEGF receptor (VEGFR) genes, Flt1 and KDR, promoter methylation status. Five hyper-VEGFR-methylation and six no-VEGFR-methylation cancer cells were used for the present study, together with human umbilical endothelial cells (HUVECs) as a control. No-VEGFR-methylation cancer cells showed higher expression of Flt1 and KDR than hyper-VEGFR-methylation cancer cells. Hyper-VEGFR-methylation cancer cells only showed increased expression and protein levels of Flt1 and KDR after treatment with the demethylase 5-aza-2'-deoxycytidine. Two drugs (a VEGF-specific-antibody, bevacizumab, and a KDR-specific-antibody) targeting extracellular VEGF-VEGFR signaling and two VEGF-specific-tyrosine kinase inhibitors (PTK/ZK and sunitinib) targeting intracellular VEGFR signaling were used in the cell proliferation assay. HUVECs showed dose- and time-dependent proliferation decrease with all tested drugs over a 72 h incubation period. No- or hyper-VEGFR-methylation cancer cells showed no significant proliferation differences after treatment with VEGF-specific-antibody or VEGFR2-specific-antibody. After PTK/ZK or sunitinib treatment, no-VEGFR-methylation cancer cells showed dose- or time-dependent decreases in proliferation. Hyper-VEGFR-methylation cancer cells also showed proliferation inhibition by VEGF-specific-tyrosine kinase inhibitors after demethylation of Flt1 and KDR. Proliferation inhibition synergistically increased after combination of demethylation with PTK/ZK in hyper-VEGF-methylation cancer cells. We observed that intracellular targeting of VEGF-VEGFR signaling could be more effective than extracellular targeting of the pathway in the suppression of proliferation of some cancer cells. In particular, the efficacy of intracellular targeting of VEGF-specific-tyrosine kinase inhibitors might be influenced by the epigenetic alteration of VEGFRs.

Myoblast transplantation therapy for chronic heart failure (HF) is impaired by early donor cell death and reduced graft viability. Although epicardial implantation of cell sheets can prevent the initial loss of transplanted cells, limited vascularization subjects the sheets to apoptotic stress. We studied the efficacy of antiapoptotic bcl2 in myoblast sheet therapy for rat chronic HF. Myocardial infarction was induced by left anterior descending coronary artery ligation and HF was allowed to develop for 4 weeks. Thereafter, wild type (L6-WT; n=16) or Bcl-2-expressing (L6-Bcl2; n=19) myoblast sheets were transplanted epicardially. Control rats (n=21) underwent left anterior descending coronary artery ligation and re-thoracotomy. Five rats were sham-operated in both surgeries. Four weeks after transplantation, only the L6-Bcl2 rats showed improved left ventricular ejection fraction. Their vascular density in the damaged myocardium was greater, and they had more proliferating cells. The L6-Bcl2 group had an increased amount of myocytes in the infarct area. Soluble factors from L6-Bcl2 sheets induced a 2.9-fold increase in endothelial cell proliferation, and enhanced endothelial wound healing as compared to the L6-WT sheets. These effects were inhibited by SU5416 and were thus dependent on Flt1/Flk1 signaling. In conclusion, bcl2 improves efficacy of myoblast sheet transplantation and promotes proangiogenic paracrine signaling.

BACKGROUND

Recent studies have shown that cytokines/cytokine receptors (C/CR) affect leukemic cell growth and survival. The goal of the current study was to investigate possible correlations between gene expression patterns of C/CR in leukemic cells, clinical features, and outcome in children with acute lymphoblastic leukemia (ALL) at first disease recurrence.

METHODS

Between January 1997 and December 2000, bone marrow (BM) samples were collected from 68 children with first ALL recurrence at diagnosis. These patients were enrolled in the ALL-REZ 95-96 disease recurrence trials of the Berlin-Frankurt-Munster study group. C/CR gene expression (interleukin [IL]-7, IL-10, IL-12p40, IL-15, IL-18, IL-7Ralpha, IL-10R1, IL-15Ralpha, interferon-gamma [IFN-gamma], vascular epithelial growth factor [VEGF], Flt1, and transforming growth factor-beta) was quantified by real-time reverse transcriptase-polymerase chain reaction and correlated with protein expression by immunofluorescence.

RESULTS

In comparison with T-lineage ALL specimens, expression of IL-10, IFN-gamma, IL-15Ralpha, and Flt1 was significantly higher in B-cell precursor (BCP) ALL specimens (P <0.01). Among BCP ALL samples, gene expression of IL-7Ralpha and Flt1 was higher in pre-B than in common or pro-B leukemic cells. Moreover, expression levels of VEGF, IL-7Ralpha, IL-10R1, and IL-15Ralpha were lower in lymphoblasts of patients with a combined BM recurrence than in those with an isolated recurrence (P <0.05). Children with IL-15Ralpha expression above the median level had a significantly better probability of event-free survival (0.65 vs. 0.34, P=0.04) and survival (0.71 vs. 0.37, P=0.02) at 5 years.

CONCLUSIONS

Expression of distinct C/CR in ALL cells was associated with lineage commitment and differentiation of leukemic cells, as well as with prognosis. It remains to be evaluated whether these prognostic and biologic findings of distinct C/CR expression in leukemic cells also have therapeutical implications for future antileukemic strategies.

BACKGROUND

Severe preeclampsia is characterized by hypertension, renal injury and placental dysfunction. Prothrombotic disorders are discovered in 10-20% of women with preeclampsia, providing the rationale for prescribing low-molecular-weight heparin (LMWH) in future pregnancies. Heparin has diverse molecular actions and appears to reduce the recurrence risk of preeclampsia in women without prothrombotic disorders. The placenta-derived anti-angiogenic splice-variant protein soluble vascular endothelial growth factor (VEGF) receptor-1 (sFLT1) is strongly implicated in the pathogenesis of the underlying endothelial dysfunction. As the placental syncytiotrophoblast is the principal source of sFLT1, we tested the hypothesis that heparin suppresses placental sFLT1 secretion.

RESULTS

First trimester placental villi exposed to LMWH (0.25-25 IU mL(-1)) in an in vitro explant model significantly increased the expression and release of sFLT1 by the syncytiotrophoblast into culture media, reducing phosphorylation of FLT1 and KDR receptors in cultured human umbilical vein endothelial cells. This response was significantly diminished in placental villi from healthy term pregnancies. Placental villi from severely preeclamptic pregnancies had a higher baseline sFLT1 release, compared with first trimester placental villi and did not respond to LMWH treatment. LMWH promoted villous cytotrophoblast proliferation (BrdU incorporation) and impaired syncytial fusion-differentiation, causing syncytiotrophoblast apoptosis (by caspase 3&7 activity and TUNEL staining) and necrosis (ADP/ATP ratio).

CONCLUSIONS

LMWH promotes sFLT1 synthesis and release from first trimester placental villi in a manner similar to that of severely preeclamptic placental villi, which antagonizes VEGF signaling in endothelial cells. These effects in part are mediated by an interaction between heparin and the cytotrophoblasts that regenerates the overlying syncytiotrophoblast responsible for sFLT1 secretion into the maternal blood.

Anti-angiogenic therapeutics has been investigated extensively for the treatment of retinal and choroidal vascular diseases, and diabetic retinopathy. Anti-Flt1 peptide of GNQWFI is an antagonistic peptide for vascular endothelial growth factor receptor 1 (VEGFR1 or Flt1) inhibiting VEGFR1-mediated endothelial cell migration and tube formation. In this work, anti-Flt1 peptide (GGNQWFI) was chemically conjugated to tetra-n-butyl ammonium modified hyaluronate (HA-TBA) via amide bond formation in dimethyl sulfoxide (DMSO) using benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP). The resulting HA - GGNQWFI conjugate self-assembled to form micelle-like nanoparticles in aqueous solution, as confirmed and characterized by transmission electron microscopy (TEM). According to in vitro biological activity tests, HA - GGNQWFI conjugate exhibited a dose-dependent inhibition effect on the binding of Flt1-Fc to VEGF(165) coated on the well. Furthermore, anti-Flt1 peptide - HA conjugate effectively inhibited retinal choroidal neovascularization (CNV) in laser induced CNV model rats. The retinal vascular permeability and the deformation of retinal vascular structure were also significantly reduced in diabetic retinopathy model rats after treatment with anti-Flt1 peptide - HA conjugate. Pharmacokinetic analysis confirmed the increased mean residence time of anti-Flt1 peptide after conjugation to HA longer than 2 weeks.

Despite wide exploitation of corticosteroid drugs for the treatment of asthma, the poor therapeutic effect on a neutrophilic subtype of asthma prohibits the full recovery of asthma patients. In this work, dexamethasone (Dexa) was loaded in Flt1 peptide-hyaluronic acid (HA) conjugate nanoparticles to overcome the limitation of corticosteroid resistance for the treatment of neutrophilic pulmonary inflammation. Flt1 peptide-HA conjugates are self-assembled to nanoparticles because of hydrophobic Flt1 peptide conjugated to HA by benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP) chemistry. In vitro bioimaging showed efficient internalization of Flt1 peptide-HA conjugate nanoparticles into lung epithelial cells by HA-receptor mediated endocytosis. Also, ex vivo imaging for the biodistribution in ICR mice revealed long-term retention of Flt1 peptide-HA conjugate nanoparticles in deep lung tissues possibly due to mucoadhesive property of HA. On the basis of bioimaging results for pulmonary drug delivery applications, we prepared Dexa-loaded Flt1 peptide-HA conjugate nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed the formation of nanoparticles, which reduced cytokine levels of lipopolysaccharide (LPS)-stimulated cells more efficiently than free Dexa. Furthermore, according to the bronchoalveolar lavage (BAL) cellularity and histological analysis, Dexa loaded Flt1 peptide-HA conjugate nanoparticles showed remarkable therapeutic effects in both eosinophilic and neutrophilic asthma model mice.

Alpha2-adrenoceptors are essential presynaptic regulators of norepinephrine release from sympathetic nerves. Previous studies in mice with targeted deletions in the 3 alpha2-adrenoceptor genes have indicated that these receptors are essential for embryonic development. In the present study, we searched for the alpha2-adrenoceptor subtype(s) involved in placental development and its molecular mechanism using mice carrying targeted deletions in alpha2-adrenoceptor genes. Congenic alpha2B-adrenoceptor-deficient mice (Adra2b-/-) developed a defect in fetal and maternal vessel formation in the placenta labyrinth at embryonic day 10.5. This defect was accompanied by reduced endothelial cell proliferation and decreased extracellular signal-regulated kinase 1/2 phosphorylation levels in Adra2b-/- as compared with Adra2b+/+ placentae. Microarray analysis of wild-type and mutant placentae (maternal genotype Adra2b+/-) revealed 179 genes, which were significantly up- or downregulated >1.5-fold in alpha2B-deficient placentae. The type 1 receptor for vascular endothelial growth factor (Flt1), which is coexpressed with alpha2B-adrenoceptors in spongiotrophoblast and giant cells of the placenta, was found to be 2.3-fold upregulated in alpha2B-deficient placentae. Neutralization of Flt1 and its soluble splice variant sFlt1 by a specific antibody in vivo prevented the vascular defect in alpha2B-deficient placentae at embryonic day 10.5. Thus, alpha2B-adrenoceptors are essential to suppress antiangiogenic (s)Flt1 in spongiotrophoblasts to control the coordinated formation of a vascular labyrinth of fetal and maternal blood vessels in the murine placenta during development.

Targeting angiogenesis through inhibition of the vascular endothelial growth factor (VEGF) pathway has been successful in the treatment of late stage colorectal cancer. However, not all patients benefit from inhibition of VEGF. Ras status is a powerful biomarker for response to anti-epidermal growth factor receptor therapy; however, an appropriate biomarker for response to anti-VEGF therapy is yet to be identified. VEGF and its receptors, FLT1 and KDR, play a crucial role in colon cancer progression; individually, these factors have been shown to be prognostic in colon cancer; however, expression of none of these factors alone was predictive of tumor response to anti-VEGF therapy. In the present study, we analyzed the expression levels of VEGFA, FLT1, and KDR in two independent colon cancer datasets and found that high expression levels of all three factors afforded a very poor prognosis. The observation was further confirmed in another independent colon cancer dataset, wherein high levels of expression of this three-gene signature was predictive of poor prognosis in patients with proficient mismatch repair a wild-type KRas status, or mutant p53 status. Most importantly, this signature also predicted tumor response to bevacizumab, an antibody targeting VEGFA, in a cohort of bevacizumab-treated patients. Since bevacizumab has been proven to be an important drug in the treatment of advanced stage colon cancer, our results suggest that the three-gene signature approach is valuable in terms of its prognostic value, and that it should be further evaluated in a prospective clinical trial to investigate its predictive value to anti-VEGF treatment.

Endometriosis is commonly associated with symptoms similar to those of gastrointestinal diseases, such as inflammatory bowel disease (IBD), leading to erroneous diagnosis and inappropriate management. The role of tumor necrosis factor alpha (TNF) in IBD is well established, but its role in endometriosis--also characterized by the activation of inflammatory mechanisms--is still under study. Furthermore, little is known about the involvement of TNF receptors. Intestinal endometriosis was surgically induced in female Sprague-Dawley rats (n = 10). Control rats (n = 10) received sutures with no implants. Samples of tissue and fluids were collected 60 days after surgery. Endometriotic implants were classified in grades, and the gastrointestinal tract was examined for damage. A significant increase was observed in protein levels of TNF and soluble TNFRSF1B in the peritoneal fluid of experimental rats compared to controls. Expression of Tnf mRNA was significantly increased both in peritoneal leukocytes and in intestinal segments associated with implants in experimental animals. Bioactivity of TNF in tissues was confirmed by overexpression of Icam1, Sele, Vegfa, Flt1 and Kdr. Gene expression of Tnfrsf1a and Tnfrsf1b was downregulated in colon and small intestine of experimental animals, possibly as a mechanism of protection against TNF cytotoxicity. Significant overexpression of genes encoding TNF receptor-associated factors that have been linked to activation of antiapoptotic pathways also was observed. Overexpression of TNF and target genes, underexpression of TNF-receptor genes, and increased shedding of TNFRSF1B in this animal model provide further evidence for involvement of the TNF system in the pathogenesis of endometriosis.

Flt1 peptide of GNQWFI is an antagonistic peptide for vascular endothelial growth factor receptor 1 (VEGFR1 or Flt1). In this work, Flt1 peptide-hyaluronate (HA) conjugates were successfully synthesized and the resulting micelle-like nanoparticles were exploited to encapsulate genistein, an inhibitor of tyrosine-specific protein kinases, for the treatment of ocular neovascularization. The mean diameter of genistein-loaded Flt1 peptide-HA conjugate micelles was measured to be 172.0±18.7 nm, with a drug-loading efficiency of 40-50%. In vitro release tests of genistein from the genistein-loaded Flt1 peptide-HA conjugate micelles exhibited the controlled release for longer than 24h. In vitro biological activity of genistein/Flt1 peptide-HA micelles was corroborated from the synergistic anti-proliferation of human umbilical vein endothelial cells (HUVECs). Furthermore, we could confirm the anti-angiogenic effect of genistein/Flt1 peptide-HA micelles from the statistically significant suppression of corneal neovascularization in silver nitrate cauterized corneas of SD rats. The retinal vascular hyperpermeability was also drastically reduced by the treatment in diabetic retinopathy model rats.

Insulin treatment is known epidemiologically as an independent risk factor for the progression of diabetic retinopathy. However, how insulin exacerbates the retinopathy is not yet fully understood. In this study, we investigate the effects of insulin on the growth and tube formation of microvascular endothelial cells (EC). When human skin microvascular EC were grown under various concentrations of insulin, DNA synthesis as well as tube formation of EC was found to be significantly stimulated. We obtained evidence that it is mainly vascular endothelial growth factor (VEGF) that mediates the angiogenic activity of insulin as follows. (1) Insulin upregulates the level of mRNA coding for secretory forms of VEGF, while the expression of the two VEGF receptor genes, kinase insert domain-containing receptor (kdr) and fms-like tyrosine kinase1 (flt1), was essentially unchanged by exposure to insulin. (2) A monoclonal antibody against human VEGF can completely neutralize both the proliferation and the tube formation of EC induced by insulin. The angiogenic effects of insulin were additive with those of hypoxia, a principal factor that causes angiogenesis. Further, insulin significantly stimulated plasminogen activator inhibitor-1 activity in EC. The results thus suggest that insulin not only elicits angiogenesis through the induction of autocrine VEGF but also is a predisposing factor for thrombogenesis, which may give rise to focal ischemia that could superdrive angiogenesis, thereby leading to the exacerbation of diabetic retinopathy.

Despite the well-accepted notion that early maternal influences persist beyond fetal life and may underlie many adult diseases, the risks imposed by the maternal environment on breast cancer development and underlying biological mechanisms remain poorly understood. In this study, we investigated whether early exposure to blueberry (BB) via maternal diet alters oncogene Wnt1-induced mammary tumorigenesis in offspring. Wnt1-transgenic female mice were exposed to maternal Casein (CAS, control) or blueberry-supplemented (CAS + 3%BB) diets throughout pregnancy and lactation. Offspring were weaned to CAS and mammary tumor development was followed until age 8 months. Tumor incidence and latency were similar for both groups; however, tumor weight at killing and tumor volume within 2 weeks of initial detection were lower (by 50 and 60%, respectively) in offspring of BB- versus control-fed dams. Dietary BB exposure beginning at weaning did not alter mammary tumor parameters. Tumors from maternal BB-exposed offspring showed higher tumor suppressor (Pten and Cdh1) and lower proproliferative (Ccnd1), anti-apoptotic (Bcl2) and proangiogenic (Figf, Flt1 and Ephb4) transcript levels, and displayed attenuated microvessel density. Expression of Pten and Cdh1 genes was also higher in mammary tissues of maternal BB-exposed offspring. Mammary tissues and tumors of maternal BB-exposed offspring showed increased chromatin-modifying enzyme Dnmt1 and Ezh2 transcript levels. Body weight, serum insulin and serum leptin/adiponectin ratio were lower for maternal BB-exposed than control tumor-bearing offspring. Tumor weights and serum insulin were positively correlated. Results suggest that dietary influences on the maternal environment contribute to key developmental programs in the mammary gland to modify breast cancer outcome in adult progeny.

The human placenta is a multifunctional organ that grows and adapts to increasing fetal demand and fluctuations in the intrauterine environment. It is subjected to physiological and pathological changes in local oxygenation, both of which induce adaptive changes. In early pregnancy a low PO2 is the normal physiological state and this is not hypoxic-there is no perturbation of ATP/ADP ratios and, if the placenta is sampled very rapidly, little HIF1α is detected in human first-trimester placental villi. Nonetheless, HIF1α can be increased and activated by culture. However, the placenta does show evidence of stress under pathological conditions. For example, in cases of pre-eclampsia where delivery by caesarean section is necessitated for maternal well-being before 34 weeks' gestation, placental endoplasmic reticulum stress is evident. Cases delivered ≥34 weeks are indistinguishable from normal term controls. One consequence of placental stress, whether oxidative, related to the endoplasmic reticulum or immunological, is that factors are released into the maternal circulation, which affects the endothelium, leading to the maternal syndrome. Soluble FLT1 may contribute directly to this and the most likely mechanism is direct action on the maternal endothelium. sFLT1 is able to form a heterodimer with cell surface VEGF receptors and is therefore able to have a dominant negative effect (in addition to acting as a competitive inhibitor by simply binding vascular endothelial growth factor A [VEGFA] and placental growth factor [PlGF]). This leads in vitro to the sensitisation of endothelial cells to low levels of TNFα.

OBJECTIVE

Current understanding of the genetic risk factors for age-related macular degeneration (AMD) is not sufficiently predictive of the clinical course. The VEGF pathway is a key therapeutic target for treatment of neovascular AMD; however, risk attributable to genetic variation within pathway genes is unclear. We sought to identify single nucleotide polymorphisms (SNPs) associated with AMD within the VEGF pathway.

METHODS

Using a tagSNP, direct sequencing and meta-analysis approach within four ethnically diverse cohorts, we identified genetic risk present in FLT1, though not within other VEGF pathway genes KDR, VEGFA, or VASH1. We used ChIP and ELISA in functional analysis.

RESULTS

The FLT1 SNPs rs9943922, rs9508034, rs2281827, rs7324510, and rs9513115 were significantly associated with increased risk of neovascular AMD. Each association was more significant after meta-analysis than in any one of the four cohorts. All associations were novel, within noncoding regions of FLT1 that do not tag for coding variants in linkage disequilibrium. Analysis of soluble FLT1 demonstrated higher expression in unaffected individuals homozygous for the FLT1 risk alleles rs9943922 (P = 0.0086) and rs7324510 (P = 0.0057). In silico analysis suggests that these variants change predicted splice sites and RNA secondary structure, and have been identified in other neovascular pathologies. These data were supported further by murine chromatin immunoprecipitation demonstrating that FLT1 is a target of Nr2e3, a nuclear receptor gene implicated in regulating an AMD pathway.

CONCLUSIONS

Although exact variant functions are not known, these data demonstrate relevancy across ethnically diverse genetic backgrounds within our study and, therefore, hold potential for global efficacy.

Severely growth-discordant monochorionic (MC) twins offer a unique opportunity to study fetal and placental growth based on a similar genetic background and maternal host environment where the healthy twin serves as an ideal control. Differences in development of MC twins may therefore be due to differential epigenetic regulation of genes involved in placental development and function. Growth-discordant twins are known for abnormal angio-architecture in the placenta of the smaller twin. Since the reasons for this phenotype are mostly unknown this study was aimed to investigate the expression and regulation of genes known to be involved in angiogenesis. We studied 10 severely growth-discordant MC twin placentas (birthweight difference ≥20%) without twin-twin-transfusion syndrome and 5 growth-concordant MC twin placentas. Growth-discordant twin placentas were phenotyped by histology. Placental mRNA expression of 88 angiogenesis-related genes was measured by PCR array. ELISA assay and immunohistochemistry were used to confirm PCR results. EpiTYPTER for DNA methylation was used to determine if methylation ratios were responsible for differential gene expression. The PCR array analysis showed significant mRNA up-regulation in the placental share of the smaller twin for several genes. These included leptin (24.6-fold, P = 0.017), fms-like tyrosine kinase 1 (Flt1, 2.4-fold, P = 0.016) and Endoglin (Eng, 1.86-fold, P = 0.078). None of the other 84 angiogenesis-related genes showed significant differences. ELISA confirmed significantly increased leptin protein expression (49.22 versus 11.03 pg/ml, P = 0.049) in the smaller twin of the discordant growth cohort. Leptin expression in smaller twins' placentas was associated with elevated DNA methylation of the leptin promotor region suggesting the inhibition of binding of a transcriptional activator/inhibitor in that region. We attempted to overcome the limitation of sample size by careful patient selection. We minimized any bias in placental sampling by random sampling from two different sites and by avoiding sampling from areas with grossly visible abnormalities using a standardized sampling protocol. In conclusion, the smaller twin's placenta is characterized by differentially increased gene expressions for Flt1 and Eng mRNA that may be causally associated with the villous pathology driven by abnormal feto-placental angiogenesis. The substantial up-regulation of leptin mRNA may be epigenetically conferred and relevant to the post-natal risk of metabolic syndrome in intrauterine growth restriction offspring with placental pathology. Growth-discordant MC twins offer unique insights into the epigenetic basis of perinatal programming.

The binding of vascular endothelial growth factor (VEGF) to its receptors stimulates tumor growth; therefore, modulation of VEGF would be a viable approach for antiangiogenic therapy. We constructed a series of soluble decoy receptors containing different VEGF receptor 1 (FLT1) and VEGF receptor 2 (KDR) extracellular domains fused with the Fc region of human immunoglobulin (Ig) and evaluated their antiangiogenic effects and antitumor effects. Results of in vitro binding and cell proliferation assays revealed that decoy receptor FP3 had the highest affinity to VEGF-A and -B. Compared with bevacizumab, FP3 more effectively inhibited human umbilical vein endothelial cell (HUVEC) migration and vessel sprouting from rat aortic rings. FP3 significantly reduced phosphorylation of AKT and ERK1/2, critical proteins in the VEGF-mediated survival pathway in endothelial cells. Moreover, FP3 inhibited tumor growth in human hepatocellular carcinoma (HepG2), breast cancer (MCF-7), and colorectal cancer (LoVo) tumor models, and reduced microvessel density in tumor tissues. The FP3-mediated inhibition of tumor growth was significantly higher than that of bevacizumab at the same dose. FP3 also demonstrated synergistic antitumor effects when combined with 5-fluorouracil (5-FU). Taken together, FP3 shows a high affinity for VEGF and produced antiangiogenic effects, suggesting its potential for treating angiogenesis-related diseases such as cancer.

Even with significant advances in operative skills and adjuvant therapies, the overall survival of patients suffering with head and neck squamous cancers (HNSCC) is unsatisfactory. Accordingly, no clinically useful prognostic biomarkers have been found yet for HNSCC. Many studies analysed the expression of potential markers in tumour tissues compared to adjacent tissues. Nevertheless, due to the sharing of the same microenvironment, adjacent tissues show molecular similarity to tumour tissues. Thus, gene expression patterns of 94 HNSCC tumorous tissues were compared with 31 adjacent tissues and with 10 tonsillectomy specimens of non-cancer individuals. The genes analysed at RNA level using quantitative RT-PCR and correlated with clinico-pathological conditions were as follows: EGF, EGFR, MKI67, BCL2, BAX, FOS, JUN, TP53, VEGF, FLT1, MMP2, MMP9, MT1A and MT2A. The elevated MT2A, BAX, EGF and JUN expression was associated with the influence of tumour cells on the rearrangement of healthy tissues, as well as a significant shift in the BAX/BCL2 ratio. Our investigation also indicated that adjacent tissues play an important role in cancerogenesis by releasing several tumour-supporting factors such as EGF. A gradual increase in the metallothionein expression, from the lowest one in tonsillectomy samples to the highest ones in tumour samples, suggests that MT expression might be tissue reaction to the presence of tumour cells. The results of this study confirmed the significance of metallothionein in tumori-genesis and gave evidences for its use as a potential HNSCC biomarker. Furthermore, this study highlighted the importance of histologically normal tumour-adjacent tissue in prediction of HNSCC progress.

Tumor-associated macrophages (TAM) are a major component of tumor stroma. It has been reported that TAMs have M2-like phenotype and facilitate tumor progression by promoting angiogenesis and immunosuppression. Melittin, a major polypeptide of bee venom, has been widely studied as an anti-cancer drug due to its cytotoxicity to malignant cells. However, very little is known regarding the effect of melittin on immune cells in the tumor microenvironment. This study focuses on the effect of melittin on TAMs in a Lewis lung carcinoma mouse model. Melittin inhibited the rapid tumor growth compared to the control in vivo. Melittin increased the M1/M2 ratio of TAMs by selectively reducing the number of CD206+ M2-like TAMs while not altering the population of CD86+ M1-like TAMs. Melittin also preferentially binds to M2 macrophages, and this binding was not associated with phagocytosis. Gene and protein expression of vascular endothelial growth factor (Vegf) and mannose receptor C type 1 (Mrc1/CD206) was reduced in M2-like bone marrow-derived macrophages by melittin treatment, but there was no significant change in the gene level of Vegf and FMS-like tyrosine kinase 1 (Flt1/VEGFR1) in tumor cells in vitro. Additionally, the levels of VEGF and CD31, markers of angiogenesis, were significantly decreased by melittin treatment in tumor tissues. This study revealed a novel role for melittin in tumor treatment and suggested that melittin could be a promising therapeutic agent for targeting M2-like TAMs.