Upregulation Of VEGF Expression Research Articles

Fatty acid activated PPARγ promotes tumorigenicity of prostate cancer cells by up regulating VEGF via PPAR responsive elements of the promoter.

In previous work, it is suggested that the excessive amount of fatty acids transported by FABP5 may facilitate the malignant progression of prostate cancer cells through a FABP5-PPARγ-VEGF signal transduction axis to increase angiogenesis. To further functionally characterise the FABP5-PPARγ-VEGF signal transduction pathway, we have, in this work, investigated the molecular mechanisms involved in its tumorigenicity promoting role in prostate cancer. Suppression of PPARγ in highly malignant prostate cancer cells produced a significant reduction (up to 53%) in their proliferation rate, invasiveness (up to 89%) and anchorage-independent growth (up to 94%) in vitro. Knockdown of PPARγ gene in PC3-M cells by siRNA significantly reduced the average size of tumours formed in nude mice by 99% and tumour incidence by 90%, and significantly prolonged the latent period by 3.5 fold. Results in this study combined with some previous results suggested that FABP5 promoted VEGF expression and angiogenesis through PPARγ which was activated by fatty acids transported by FABP5. Further investigations showed that PPARγ up-regulated VEGF expression through acting with the PPAR-responsive elements in the promoter region of VEGF gene in prostate cancer cells. Although androgen can modulate VEGF expression through Sp1/Sp3 binding site on VEGF promoter in androgen-dependent prostate cancer cells, this route, disappeared as the cells gradually lost their androgen dependency; was replaced by the FABP5-PPARγ-VEGF signalling pathway. These results suggested that the FABP5-PPARγ-VEGF signal transduction axis, rather than androgen modulated route, may be a more important novel therapeutic target for angiogenesis-suppression treatment of castration resistant prostate cancer.

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The aim of wound care is to promote wound healing in the shortest time possible, and plants are a great source of medicines, especially in traditional medicine. Traditionally, medicinal plants have been used for many years as topical and internal preparations to promote wound repair. This work will give an overview of twelve West Africa medicinal plant studies and their active phytochemicals in direct wound healing. The process of wound healing is promoted by several herbal extracts, which are composed of active agents like triterpenes, alkaloids, flavonoids, tannins, saponins, anthraquinones, and other biomolecules. 55% of overviewed plants contain tannins and we found that 45% of them contain terpenoids. Saponins are present at a level of 36% in these overviewed plants. Finally, we remarked that 80% of plants studied here contain flavonoids. The antioxidant and anti-inflammatory activities of flavonoids were believed to be one of the important mechanisms in wound healing and in the presence of tannin it improved the regeneration and organization of the new tissue and hastened the wound healing process. Sterols and polyphenols are also responsible for wound healing due to free radical-scavenging and antioxidant activity, which are known to reduce lipid peroxidation. Cactus extract up-regulates VEGF expression in wounded skin, stimulating in return angiogenesis for supplying nutrients and oxygen for skin regrowth. The expression of MMPs revealed the enhanced healing pattern in the E. guineensis leaf extract treated rats group. In conclusion, biochemically wound healing process is promoted by active agents in herbal extracts and those components act synergistically. Key words: Medicinal plants, phytochemicals, biochemically wound healing.

Correlation of WT1 and VEGF Expression with Angiogenesis in Bone Marrow Biopsies of Multiple Myeloma Patients

To investigate the relationship of WT1 and VEGF expression with angiogenesis in bone marrow biopsies of multiple myeloma patients. VEGF, WT1 expression and microvessel density (MVD) of 62 cases of multiple myeloma and 10 normal bone marrow tissue were detected by in situ hybridization and immunohistochemistry SP method. Microvessel density (MVD) of the control group was (45±6)/visual field, and while MVD of the multiple myeloma group was (84±26)/sight, and statistical analysis showed that MVD in multiple myeloma group was significantly higher than that in control group (P<0.05); in 62 cases of multiple myeloma the VEGF positive rate was 51.6% (32/62), and MVD in VEGF-positive group was significantly higher than that in the negative group (P<0.05). WT1 positive rate was 30.6% (19/62), and MVD in WT1-positive group was significantly higher than that in the negative group (P<0.05). And statistical analysis showed that WT1 expression significantly correlated with VEGF expression (P<0.05). WT1 high expression of multiple myeloma bone tissue can up-regulate VEGF expression and promote angiogenesis.

A phase II study of 5-fluorouracil (5-FU), ziv-aflibercept, and radiation for the preoperative and adjuvant treatment of patients (pts) with stage II/III rectal cancer.

3607 Background: Radiation exposure upregulates VEGF expression which protects endothelial cells from the effects of radiation therapy. Combining an angiogenesis inhibitor with radiation therapy ma...

Alterations in expression of elastogenic and angiogenic genes by different conditions of mechanical ventilation in newborn rat lung.

Mechanical ventilation is an important risk factor for development of bronchopulmonary dysplasia. Here we investigated the effects of different tidal volumes (VT) and duration of ventilation on expression of genes involved in alveolarization [tropoelastin (Eln), lysyloxidase-like 1 (Loxl1), fibulin5 (Fbln5), and tenascin-C (Tnc)] and angiogenesis [platelet derived growth factors (Pdgf) and vascular endothelial growth factors (Vegf) and their receptors] in 8-day-old rats. First, pups were ventilated for 8 h with low (LVT: 3.5 ml/kg), moderate (MVT: 8.5 ml/kg), or high (HVT: 25 ml/kg) tidal volumes. LVT and MVT decreased Tnc expression, whereas HVT increased expression of all three elastogenic genes and Tnc. PDGF α-receptor mRNA was increased in all ventilation groups, while Pdgfb expression was decreased after MVT and HVT ventilation. Only HVT ventilation upregulated Vegf expression. Independent of VT, ventilation upregulated Vegfr1 expression, while MVT and HVT downregulated Vegfr2 expression. Next, we evaluated duration (0-24 h) of MVT ventilation on gene expression. Although expression of all elastogenic genes peaked at 12 h of ventilation, only Fbln5 was negatively affected at 24 h. Tnc expression decreased with duration of ventilation. Changes in expression of Pdgfr and Vegfr were maximal at 8 h of ventilation. Disturbed elastin fiber deposition and decrease in small vessel density was only observed after 24 h. Thus, an imbalance between Fbln5 and Eln expression may trigger dysregulated elastin fiber deposition during the first 24 h of mechanical ventilation. Furthermore, ventilation-induced alterations in Pdgf and Vegf receptor expression are tidal volume dependent and may affect pulmonary vessel formation.

Chronic inflammation and angiogenic signaling axis impairs differentiation of dental-pulp stem cells.

Dental-pulp tissue is often exposed to inflammatory injury. Sequested growth factors or angiogenic signaling proteins that are released following inflammatory injury play a pivotal role in the formation of reparative dentin. While limited or moderate angiogenesis may be helpful for dental pulp maintenance, the induction of significant level of angiogenesis is probably highly detrimental. Hitherto, several studies have addressed the effects of proinflammatory stimuli on the survival and differentiation of dental-pulp stem cells (DPSC), in vitro. However, the mechanisms communal to the inflammatory and angiogenic signaling involved in DPSC survival and differentiation remain unknown. Our studies observed that short-term exposure to TNF-α (6 and 12 hours [hrs]) induced apoptosis with an upregulation of VEGF expression and NF-κB signaling. However, long-term (chronic) exposure (14 days) to TNF-α resulted in an increased proliferation with a concomitant shortening of the telomere length. Interestingly, DPSC pretreated with Nemo binding domain (NBD) peptide (a cell permeable NF-κB inhibitor) significantly ameliorated TNF-α- and/or VEGF-induced proliferation and the shortening of telomere length. NBD peptide pretreatment significantly improved TNF-α-induced downregulation of proteins essential for differentiation, such as bone morphogenic proteins (BMP)-1 & 2, BMP receptor isoforms-1&2, trasnforming growth factor (TGF), osteoactivin and osteocalcin. Additionally, inhibition of NF-κB signaling markedly increased the mineralization potential, a process abrogated by chronic exposure to TNF-α. Thus, our studies demonstrated that chronic inflammation mediates telomere shortening via NF-κB signaling in human DPSC. Resultant chromosomal instability leads to an emergence of increased proliferation of DPSC, while negatively regulating the differentiation of DPSC, in vitro.

Abstract 1599: Elevated expression of ZEB1 upregulates VEGF expression and induces tumor angiogenesis in breast cancer

Abstract Background: Angiogenesis is essential for the growth and metastasis of solid tumors, including breast cancer. Although the zinc finger-homeodomain transcription factor ZEB1 is implied as a key regulatory factor in multistep carcinogenesis of breast cancer, its direct role in the regulation of tumor angiogenesis has not been well elucidated. In this report, we extended our study to examine the potential effect of ZEB1 in breast cancer angiogenesis and its molecular mechanism using the in vitro and in vivo models. Materials and Methods: Quantitative RT-PCR, immunoblotting, and ELISA were used to detect ZEB1-induced expression and/or secretion of VEGF in the absence or presence of the indicated signaling pathway inhibitors (the PI3K, NF-κB, and MAPKs pathways) in MDA-MB-231 breast cancer cells. Tube formation assay was performed to detect ZEB1-driven angiogenesis using human umbilical vein endothelial cells (HUVEC). Luciferase and CHIP assays were used to determine the transcriptional activity of the wild-type and mutant VEGF promoters affected by ZEB1. A nude mouse tumor xenograft model was used to examine ZEB1-driven angiogenesis in vivo. The relationship between the expression of ZEB1 and VEGF protein in human breast cancer specimens was assessed by immunohistochemistry. Results: We found that ectopic expression of ZEB1 promotes the expression of VEGF at both the mRNA and the protein levels in MDA-MB-231 cells, which effect is specifically mediated through the p38 and PI3K pathways. The conditioned medium derived from ZEB1-overexpressing MDA-MB-231 cells significantly induces the tube formation of HUVEC compared with that from control-overexpressing cells. Importantly, elevated expression of ZEB1 resulted in an increased angiogenesis in a nude mouse tumor xenograft model. We further moved on to detect whether ZEB1 is a bona-fide transcriptional regulator of VEGF. The results of luciferase and CHIP assays showed that ZEB1 transcriptionally induces the promoter activity of human VEGF by recruiting Sp1 to its biding sites on the VEGF promoter, thus up-regulating VEGF expression in MDA-MB-231 cells. Through the study of breast cancer specimens, we found a strong positive correlation between ZEB1 and VEGF protein expression, further supporting the contribution of ZEB1/VEGF cascade to tumor angiogenesis in breast cancer. Conclusions: Our data demonstrated that ZEB1 up-regulates VEGF expression and thus induces tumor angiogenesis in breast cancer. Thus, inhibition of VEGF expression by down-regulating ZEB1 provides a potential new strategy for overcoming tumor angiogenesis. Citation Format: Qi Tong, Lingjia Liu, Lin Liang, Yang Gao, Shuang Yang. Elevated expression of ZEB1 upregulates VEGF expression and induces tumor angiogenesis in breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1599. doi:10.1158/1538-7445.AM2014-1599

Prophylactic effects of prostaglandin E2 on NSAID-induced enteropathy-role of EP4 receptors in its protective and healing-promoting effects.

Prostaglandin E2 not only prevents NSAID-generated small intestinal lesions, but also promotes their healing. The protective effects of prostaglandin E2 are mediated by the activation of EP4 receptors and functionally associated with the stimulation of mucus/fluid secretions and inhibition of intestinal hypermotility, resulting in the suppression of enterobacterial invasion and iNOS up-regulation, which consequently prevents intestinal lesions. Prostaglandin E2 also promotes the healing of intestinal damage by stimulating angiogenesis through the up-regulation of VEGF expression via the activation of EP4 receptors. These findings have contributed to a further understanding of the mechanisms responsible for 'protective' and 'healing-promoting' effects of prostaglandin E2 and the development of new strategies for the prophylactic treatment of NSAID-induced enteropathy.

Nuclear factor kappa-B signaling is integral to ocular neovascularization in ischemia-independent microenvironment.

Retinal ischemia promotes the upregulation of VEGF expression and accounts for most pathological features of retinal neovascularization (NV). Paradoxically, VEGF remains the pivotal stimulator of ocular NV, despite the absence of ischemia. Therefore, the central question arises as to how the various molecular mechanisms interplay in ischemia-independent NV. It's been suggested that NFκB plays a crucial role in the pathogenesis of diabetic vasculopathies. Here, we dissected the molecular mechanism of ocular NV in the rho/VEGF transgenic mouse model, which develops subretinal NV in ischemia-independent microenvironment. Furthermore, we examined whether intravitreal administration of YC-1, a HIF-1 inhibitor, can modulate the activation of NFκB and its downstream angiogenic signaling in the mouse retina. We demonstrated that YC-1 inhibited retinal NFκB/p65 DNA binding activity and downregulated NFκB/p65, FAK, α5β1, EPO, ET-1, and MMP-9 expression at the message and the protein levels. In addition, YC-1 significantly inhibited subretinal NV by reducing the number of neovascular lesions, the area of each lesion and the total area of NV per retina. We further investigated the influence of VEGF signaling pathway on HIF-1α transcriptional activity to substantiate that this mouse model develops subretinal NV in an ischemia-independent microenvironment. Our data demonstrated that VEGF overexpression didn't have any impact on HIF-1α transcriptional activity, whereas treatment with YC-1 significantly inhibited endogenous HIF-1 activity. Our study suggests that retinal NFκB transcriptional activity is pivotal to ischemia-independent mechanisms, which lead to the local activation of angiogenic cascades. Our data also indicate that the nexus between VEGF and NFκB is implicated in triggering the angiogenic cascade that promotes retinal NV. Hence, targeting the VEGF/NFκB axis may act in a negative feedback loop to suppress ocular NV. This study suggests that inhibition of NFκB activation may be a means of turning off a “master switch” responsible for initiating and perpetuating these ocular pathologies.

Acupuncture Promotes Angiogenesis after Myocardial Ischemia through H3K9 Acetylation Regulation at VEGF Gene

BackgroundAcupuncture exerts cardioprotective effects on several types of cardiac injuries, especially myocardial ischemia (MI), but the mechanisms have not yet been well elucidated. Angiogenesis mediated by VEGF gene expression and its modification through histone acetylation has been considered a target in treating myocardial ischemia. This study aims to exam whether modulation of angiogenesis through H3K9 acetylation regulation at VEGF gene is one possible cardioprotective mechanism of acupuncture.ResultsWe generated rat MI models by ligating the left anterior descending coronary artery and applied electroacupuncture (EA) treatment at the Neiguan (PC6) acupoint. Our results showed that acupuncture reversed the S-T segment change, reduced Q-wave area, decreased CK, CK-MB, LDH levels, mitigated myocardial remodeling, and promoted microvessel formation in the MI heart. RNA-seq analysis showed that VEGF-induced angiogenesis signaling was involved in the modulation of EA. Western blot results verified that the protein expressions of VEGF, Ras, phospho-p44/42 MAPK, phospho-p38 MAPK, phospho-SAPK/JNK and Akt, were all elevated significantly by EA treatment in the MI heart. Furthermore, increased H3K9 acetylation was also observed according with the VEGF. ChIP assay confirmed that EA treatment could notably stimulate the recruitment of H3K9ace at the VEGF promoter.ConclusionsOur study demonstrates for the first time that acupuncture can effectively up-regulate VEGF expression through H3K9 acetylation modification directly at the VEGF promoter and hence activate VEGF-induced angiogenesis in rat MI models. We employed high throughput sequencing in this study and, for the first time, generated genome-wide gene expression profiles both in the rat MI model and in acupuncture treatment.

MP35-03 TWIST UP-REGULATES VEGF EXPRESSION WITH HIF IN HYPOXIA

You have accessJournal of UrologyKidney Cancer: Basic Research III1 Apr 2014MP35-03 TWIST UP-REGULATES VEGF EXPRESSION WITH HIF IN HYPOXIA Takeshi Yoshida, Ryoichi Hamasuna, Naohiro Fujimoto, and Tetsuro Matsumoto Takeshi YoshidaTakeshi Yoshida More articles by this author , Ryoichi HamasunaRyoichi Hamasuna More articles by this author , Naohiro FujimotoNaohiro Fujimoto More articles by this author , and Tetsuro MatsumotoTetsuro Matsumoto More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1046AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES VHL (von-hippel-lindaw protein), which is E3 ubiquitin protein ligase, interacts with HIF1a (hypoxia-inducible factor-1a) and degrades HIF leading to suppress transcriptional activation of HIF target gene in normoxia condition. In hypoxia, HIF is not degraded by VHL and activate downstream genes such as VEGF. Nowadays several kinds of molecular target agents against VEGF signaling pathway are developed. But molecular target agents are limited in its effect. There are much more unknown molecules controlling this pathway. In this study, we focused on Twist, which is involved in EMT (epithelial-mesenchymal transition) and demonstrated its effect on VHL-HIF signaling pathway. METHODS Twist, siRNA Twist and other proteins was investigated in the human renal tumor cell line ACHN. Transcriptional activity of VEGF by Twist was measured by reporter assay using HIF responsive element (HRE) reporter plasmids co-transfected with Twist expression plasmid (or siRNA-Twist) in renal tumor cell line ACHN and other cell lines. Binding of Twist to VEGF promoter in tumor cells were shown by chromatin immunoprecipitation (ChIP) assay using antibody against Twist. Immunoprecipitated cleaved-DNA was amplified by PCR using primers coded with VEGF promoter sequence. Electrophoresis Mobility Shift Assay (EMSA) were demonstrated to show binding of Twist for specific sequence (about -1000bp upstream from start point of transcription) in VEGF promoter. To show molecular binding between Twist and HIF, Co-immunoprecipitation (Co-IP) assay were performed. Expression of VEGF by Twist was investigated by western assay and immuno-fluorescent staining in tumor cell line. RESULTS Overexpressed Twist activated HRE reporter activity. VEGF promoter activity was activated by Twist in hypoxia. ChIP assay showed Twist binding to VEGF promoter in ACHN cells. Co-IP assay showed the binding of Twist and HIF. VEGF was overexpressed in Twist transfected cells. CONCLUSIONS We report the association of Twist with VHL-HIF signaling pathway. This suggests that Twist expression involves in tumor vascularization in renal tumor. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e371 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Takeshi Yoshida More articles by this author Ryoichi Hamasuna More articles by this author Naohiro Fujimoto More articles by this author Tetsuro Matsumoto More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Differential roles of prostaglandin E-type receptors in activation of hypoxia-inducible factor 1 by prostaglandin E1in vascular-derived cells under non-hypoxic conditions

Prostaglandin E1 (PGE1), known pharmaceutically as alprostadil, has vasodilatory properties and is used widely in various clinical settings. In addition to acute vasodilatory properties, PGE1 may exert beneficial effects by altering protein expression of vascular cells. PGE1 is reported to be a potent stimulator of angiogenesis via upregulation of VEGF expression, which is under the control of the transcription factor hypoxia-inducible factor 1 (HIF-1). However, the molecular mechanisms behind the phenomenon are largely unknown. In the present study, we investigated the mechanism by which PGE1 induces HIF-1 activation and VEGF gene expression in human aortic smooth muscle cells (HASMCs) and human umbilical vein endothelial cells (HUVECs), both vascular-derived cells. HUVECs and HASMCs were treated with PGE1 at clinically relevant concentrations under 20% O2 conditions and HIF-1 protein expression was investigated. Expression of HIF- 1α protein and the HIF-1-downstream genes were low under 20% O2 conditions and increased in response to PGE1 treatment in both HUVECs and HASMCs in a dose- and time-dependent manner under 20% O2 conditions as comparable to exposure to 1% O2 conditions. Studies using EP-receptor-specific agonists and antagonists revealed that EP1 and EP3 are critical to PGE1-induced HIF-1 activation. In vitro vascular permeability assays using HUVECs indicated that PGE1 increased vascular permeability in HUVECs. Thus, we demonstrate that PGE1 induces HIF- 1α protein expression and HIF-1 activation under non-hypoxic conditions and also provide evidence that the activity of multiple signal transduction pathways downstream of EP1 and EP3 receptors is required for HIF-1 activation.

Development of a Multiplex Sandwich Aptamer Microarray for the Detection of VEGF165 and Thrombin

In this work we have developed a multiplex microarray system capable of detecting VEGF165 and thrombin. We recently described a Sandwich Aptamer Microarray (SAM) for thrombin detection feasible for use in multiplex microarrays; here we describe a new aptasensor for VEGF165 detection employing Vap7 and VEa5, two DNA aptamers recognizing different sites of the protein. The aptamers were modified to be adapted to the solid phase platform of SAM and their capability to simultaneously recognize VEGF165 by forming a ternary complex was analyzed in solution. Having so defined the best tandem arrangement of modified aptamers, we set up the aptasensor for VEGF165, and finally analyzed the multiplex system with the two aptasensors for the simultaneous detection of VEGF165 and thrombin. The results indicate that each sandwich is specific, even when the two proteins are mixed. The system performance is consistent with the behavior evidenced by the biochemical analysis, which proves to be valuable to drive the evaluation and refinement of aptamers prior to or along the development of a detection platform. Since thrombin upregulates VEGF expression, the simultaneous recognition of these two proteins could be useful in the analysis of biomarkers in pathologies characterized by neo-angiogenesis.

Abstract 3896: A metabolic enzyme as a pro-angiogenic activator in premalignant mammary cells.

Abstract A crucial step in cancer progression is the development of a high-density vascular network, the angiogenic switch. During carcinogenesis breast angiogenesis occurs at hyperplasia before atypia, reaching maximum vascularization between ductal carcinoma in situ and invasive carcinoma. Altered energy metabolism is an early hallmark of several human malignancies. Fatty Acid Synthase (FASN) is a metabolic enzyme that catalyzes the synthesis of Palmitate from Malonyl CoA. With the exception of liver and adipose tissue, normal cells have low levels of FASN and activity. Here we show that FASN expression is progressively up-regulated in the early steps of human breast carcinogenesis. While under hypoxia FASN expression is downregulated in non-transformed breast epithelial cells that form normal ducts. In pre-malignant breast cancer lesions under similar conditions, FASN expression is upregulated. These data suggest a link between FASN-hypoxia-progression. In addition, we observed that in early stages of breast carcinogenesis, FASN regulates the expression of hypoxia genes, which in turn results in increase vascularization and angiogenic markers. Forced expression of FASN in non-transformed breast epithelial cells resulted in increased activity of HIF-1α and upregulation of VEGF expression. Furthermore, FASN-expressing non-transformed breast epithelial cells under hypoxia conditions produced the necessary factors to stimulate angiogenesis, as measured by tube formation and migration in HUVEC cells. These data provide evidence that FASN promotes pro-angiogenesis under hypoxia at the early onset of breast carcinoma; thus, it could be considered as a target for breast cancer chemoprevention. Citation Format: Anatilde M. Gonzalez-Guerrico, Ingrid Espinoza, Ruth Lupu. A metabolic enzyme as a pro-angiogenic activator in premalignant mammary cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3896. doi:10.1158/1538-7445.AM2013-3896

Naturally derived factors and their role in the promotion of angiogenesis for the healing of chronic wounds

Chronic diseases such as vascular disease and diabetes are witnessing a global increase in prevalence. Such diseases often predispose patients to the development of severe, debilitating, chronic wounds. Angiogenesis, the formation of new capillaries from the pre-existing vascular network, is an essential component of wound healing and aberrant angiogenesis is evident in almost all chronic wounds. Natural products, derived from both plants and animals, provide a significant haven of compounds which have proved to be of great benefit to man and his ailments. Whilst significant advances have been made in the understanding of impaired angiogenesis in a non-healing wound, in the clinical setting, few effective agents exist that can expedite wound healing and closure. The lack of effective healing agents has led to a renewed interest in investigations into natural wound healing resources. In this review, we collate new evidence that details the potential for several natural compounds to promote angiogenesis and wound healing, most predominately via the up regulation of VEGF expression, that warrant urgent further investigation for development into new pro-angiogenic/wound healing therapies.

P85 mediates NFAT3-dependent VEGF induction in the cellular UVB response

Exposure to solar ultraviolet B (UVB) radiation is known to induce several pathological reactions in the skin. In these processes, upregulation of VEGF expression has been demonstrated to be important in angiogenesis-associated photodamage and even skin cancers. However, the signaling events that are responsible for VEGF induction under UVB exposure have not been fully defined. Here, we demonstrate that the regulatory subunit of the phosphoinositide 3-kinase (PI3K), p85α, plays a role in mediating UVB-induced VEGF expression in mouse embryonic fibroblasts (MEFs) and mouse epithermal cells, the effect of which is unrelated to the PI3K activity. The transcriptional factor NFAT3 functions as a downstream target of p85α to mediate the induction of VEGF expression in the UVB response. Although lacking NFAT3-binding ability, p85α is required for the recruitment of NFAT3 to the NFAT-response element within the vegf promoter. Furthermore, by identifying the adjacent NFAT- and AP-1-binding sites within the vegf promoter, we also found an induced interaction between NFAT3 and one of the AP-1 components, c-Fos, after UVB irradiation. Without the aid of c-Fos, NFAT3 lost its vegf-promoter-binding ability. Taken together, our results reveal a novel PI3K-independent role for p85α in controlling VEGF induction during the cellular UVB response by regulating NFAT3 activity. Targeting p85α might be helpful for preventing UVB-induced angiogenesis and the associated photodamage.

PEP-1-CAT-Transduced Mesenchymal Stem Cells Acquire an Enhanced Viability and Promote Ischemia-Induced Angiogenesis

ObjectivePoor survival of mesenchymal stem cells (MSC) compromised the efficacy of stem cell therapy for ischemic diseases. The aim of this study is to investigate the role of PEP-1-CAT transduction in MSC survival and its effect on ischemia-induced angiogenesis.MethodsMSC apoptosis was evaluated by DAPI staining and quantified by Annexin V and PI double staining and Flow Cytometry. Malondialdehyde (MDA) content, lactate dehydrogenase (LDH) release, and Superoxide Dismutase (SOD) activities were simultaneously measured. MSC mitochondrial membrane potential was analyzed with JC-1 staining. MSC survival in rat muscles with gender-mismatched transplantation of the MSC after lower limb ischemia was assessed by detecting SRY expression. MSC apoptosis in ischemic area was determined by TUNEL assay. The effect of PEP-1-CAT-transduced MSC on angiogenesis in vivo was determined in the lower limb ischemia model.ResultsPEP-1-CAT transduction decreased MSC apoptosis rate while down-regulating MDA content and blocking LDH release as compared to the treatment with H2O2 or CAT. However, SOD activity was up-regulated in PEP-1-CAT-transduced cells. Consistent with its effect on MSC apoptosis, PEP-1-CAT restored H2O2-attenuated mitochondrial membrane potential. Mechanistically, PEP-1-CAT blocked H2O2-induced down-regulation of PI3K/Akt activity, an essential signaling pathway regulating MSC apoptosis. In vivo, the viability of MSC implanted into ischemic area in lower limb ischemia rat model was increased by four-fold when transduced with PEP-1-CAT. Importantly, PEP-1-CAT-transduced MSC significantly enhanced ischemia-induced angiogenesis by up-regulating VEGF expression.ConclusionsPEP-1-CAT-transduction was able to increase MSC viability by regulating PI3K/Akt activity, which stimulated ischemia-induced angiogenesis.

Acrolein Induces Endoplasmic Reticulum Stress and Causes Airspace Enlargement

BackgroundGiven the relative abundance and toxic potential of acrolein in inhaled cigarette smoke, it is surprising how little is known about the pulmonary and systemic effects of acrolein. Here we test the hypothesis whether systemic administration of acrolein could cause endoplasmic reticulum (ER) stress, and lung cell apoptosis, leading to the enlargement of the alveolar air spaces in rats.MethodsAcute and chronic effects of intraperitoneally administered acrolein were tested. Mean alveolar airspace area was measured by using light microscopy and imaging system software. TUNEL staining and immunohistochemistry (IHC) for active caspase 3 and Western blot analysis for active caspase 3, and caspase 12 were performed to detect apoptosis. The ER-stress related gene expression in the lungs was determined by Quantitative real-time PCR analysis. Acrolein-protein adducts in the lung tissue were detected by IHC.ResultsAcute administration of acrolein caused a significant elevation of activated caspase 3, upregulation of VEGF expression and induced ER stress proteins in the lung tissue. The chronic administration of acrolein in rats led to emphysematous lung tissue remodeling. TUNEL staining and IHC for cleaved caspase 3 showed a large number of apoptotic septal cells in the acrolein-treated rat lungs. Chronic acrolein administration cause the endoplasmic reticulum stress response manifested by significant upregulation of ATF4, CHOP and GADd34 expression. In smokers with COPD there was a considerable accumulation of acrolein-protein adducts in the inflammatory, airway and vascular cells.ConclusionsSystemic administration of acrolein causes endoplasmic reticulum stress response, lung cell apoptosis, and chronic administration leads to the enlargement of the alveolar air spaces and emphysema in rats. The substantial accumulation of acrolein-protein adducts in the lungs of COPD patients suggest a role of acrolein in the pathogenesis of emphysema.

Low-power laser irradiation (LPLI) promotes VEGF expression and vascular endothelial cell proliferation through the activation of ERK/Sp1 pathway

Angiogenesis, the growth of new blood vessels from pre-existing vessels, represents an excellent therapeutic target for the treatment of wound healing and cardiovascular disease. Herein, we report that LPLI (low-power laser irradiation) activates ERK/Sp1 (extracellular signal-regulated kinase/specificity protein 1) pathway to promote VEGF expression and vascular endothelial cell proliferation. We demonstrate for the first time that LPLI enhances DNA-binding and transactivation activity of Sp1 on VEGF promoter in vascular endothelial cells. Moreover, Sp1-regulated transcription is in an ERK-dependent manner. Activated ERK by LPLI translocates from cytoplasm to nuclear and leads to increasing interaction with Sp1, triggering a progressive phosphorylation of Sp1 on Thr453 and Thr739, resulting in the upregulation of VEGF expression. Furthermore, selective inhibition of Sp1 by mithramycin-A or shRNA suppresses the promotion effect of LPLI on cell cycle progression and proliferation, which is also significantly abolished by inhibition of ERK activity. These findings highlight the important roles of ERK/Sp1 pathway in angiogenesis, supplying potential strategy for angiogenesis-related diseases with LPLI treatment.

Primary Xenografts of Human Prostate Tissue as a Model to Study Angiogenesis Induced by Reactive Stroma

Characterization of the mechanism(s) of androgen-driven human angiogenesis could have significant implications for modeling new forms of anti-angiogenic therapies for CaP and for developing targeted adjuvant therapies to improve efficacy of androgen-deprivation therapy. However, models of angiogenesis by human endothelial cells localized within an intact human prostate tissue architecture are until now extremely limited. This report characterizes the burst of angiogenesis by endogenous human blood vessels in primary xenografts of fresh surgical specimens of benign prostate or prostate cancer (CaP) tissue that occurs between Days 6–14 after transplantation into SCID mice pre-implanted with testosterone pellets. The wave of human angiogenesis was preceded by androgen-mediated up-regulation of VEGF-A expression in the stromal compartment. The neo-vessel network anastomosed to the host mouse vascular system between Days 6–10 post-transplantation, the angiogenic response ceased by Day 15, and by Day 30 the vasculature had matured and stabilized, as indicated by a lack of leakage of serum components into the interstitial tissue space and by association of nascent endothelial cells with mural cells/pericytes. The angiogenic wave was concurrent with the appearance of a reactive stroma phenotype, as determined by staining for α-SMA, Vimentin, Tenascin, Calponin, Desmin and Masson's trichrome, but the reactive stroma phenotype appeared to be largely independent of androgen availability. Transplantation-induced angiogenesis by endogenous human endothelial cells present in primary xenografts of benign and malignant human prostate tissue was preceded by induction of androgen-driven expression of VEGF by the prostate stroma, and was concurrent with and the appearance of a reactive stroma phenotype. Androgen-modulated expression of VEGF-A appeared to be a causal regulator of angiogenesis, and possibly of stromal activation, in human prostate xenografts.