Downregulation Of Vascular Endothelial Growth Factor Expression Research Articles

Carbamylated erythropoietin mediates retinal neuroprotection in streptozotocin-induced early-stage diabetic rats.

The neuroprotective effect of carbamylated erythropoietin (CEPO), an erythropoietin (EPO) derivative, in diabetic retinopathy (DR) has not been clearly verified. We conducted this study to investigate the potential neuroprotective role of CEPO in a streptozotocin-induced diabetic rat model. Streptozotocin-induced diabetic rats and blank controls were treated with or without CEPO and EPO for 4 weeks. Retinal functional and histological changes were quantified by electroretinogram, light microscopy, and terminal dUTP nick end labeling assay. Gene and protein levels of colony-stimulating factor 2 receptor beta, low-affinity (CD131), EPO receptor (EPOR), THY1, glial fibrillary acidic protein (GFAP), and vascular endothelial growth factor (VEGF-A) in retinal tissues were determined by real-time PCR and western blotting, respectively. Vascular penetration was assessed by fluorescein retinal angiography. Diabetic rats had decreased retinal thickness, decreased ganglion cells, and increased retinal neuron apoptosis. CEPO increased CD131 and THY1 expression, while EPO increased EPOR expression. High glucose increased GFAP expression in the diabetic group, but both CEPO and EPO attenuated the trend for increase. CEPO downregulated VEGF-A expression. The amplitudes of b-wave and oscillatory potentials were decreased in the untreated diabetic group, whereas neither parameter decreased in diabetic rats after CEPO or EPO treatment. Vascular leakage and microaneurysms in the diabetic group were significantly improved following CEPO treatment. CEPO has similar anti-apoptotic effects to EPO in DR, but CEPO does not induce neovascularization. CEPO may exert neuroprotective effects via its receptor CD131.

Tanshinone IIA inhibits HIF-1α and VEGF expression in breast cancer cells via mTOR/p70S6K/RPS6/4E-BP1 signaling pathway.

Hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) play important roles in angiogenesis and tumor growth. Tanshinone IIA (T2A) is a novel antiangiogenic agent with promising antitumor effects; however, the molecular mechanism underlying the antiangiogenic effects of T2A remains unclear. In the present study, we provided evidence showing that T2A inhibited angiogenesis and breast cancer growth by down-regulating VEGF expression. Specifically, T2A repressed HIF-1α expression at the translational level and inhibited the transcriptional activity of HIF-1α, which led to the down-regulation of VEGF expression. Suppression of HIF-1α synthesis by T2A correlated with strong dephosphorylation of mammalian target of rapamycin (mTOR) and its effectors ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E-binding protein-1 (4E-BP1), a pathway regulating HIF-1α expression at the translational level. In addition, we also found that T2A inhibited the angiogenesis and growth of human breast cancer xenografts in nude mice through suppression of HIF-1α and VEGF. Our study provides novel perspectives and potential targets for the treatment of human breast cancer.

Efficacy of Arsenic Trioxide in the Treatment of Malignant Pleural Effusion Caused by Pleural Metastasis of Lung Cancer.

The aim of the study was to investigate the mechanism of arsenic trioxide (As2O3) in the treatment of malignant pleural effusion (MPE) caused by pleural metastasis of lung cancer. A mouse model of MPE caused by pleural metastasis of lung cancer was first established, and As2O3 was then intraperitoneally injected to treat the MPE. Mice treated with bevacizumab and bleomycin were included as positive controls, and placebo equivalents were also used as negative controls. The effects of As2O3 on MPE volume, pleural vessel density, vascular permeability, expression of angiogenic function-related factors, including vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-α), as well as nuclear factor-κB (NF-κB) activity in pleural carcinomatosis, were observed. Intraperitoneal injection of As2O3 reduced the volume of MPE and decreased vascular density and permeability in pleural metastatic nodules in a dose-dependent manner. Moreover, dose-dependent decreases in VEGF and TNF-α expression in MPE, and NF-κB activity in pleural carcinomatosis, were also found after As2O3 treatment. We showed that As2O3 can down-regulate VEGF expression via inhibition of NF-κB, and decrease vascular density and permeability in pleural metastatic nodules, thereby eliciting its effects on MPE caused by pleural metastasis of lung cancer. Our results provide a foundation for an As2O3-based clinical treatment program.

Abstract 170: Exosomes derived from mesenchymal stem cells suppress angiogenesis by down-regulating VEGF expression in breast cancer cells

Abstract Exosomes are small membrane vesicles released by a variety of cell types. Exosomes contain genetic materials, such as mRNAs and microRNAs (miRNAs), implying that they may play a pivotal role in cell-to-cell communication. Mesenchymal stem cells (MSCs), which potentially differentiate into multiple cell types, can migrate to the tumor sites and have been reported to exert complex effects on tumor progression. To elucidate the role of MSCs within the tumor microenvironment, previous studies have suggested various mechanisms such as immune modulation and secreted factors of MSCs. However, the paracrine effects of MSC-derived exosomes on the tumor microenvironment remain to be explored. The hypothesis of this study was that MSC-derived exosomes might reprogram tumor behavior by transferring their molecular contents. To test this hypothesis, exosomes from MSCs were isolated and characterized. MSC-derived exosomes exhibited different protein and RNA profiles compared with their donor cells and these vesicles could be internalized by breast cancer cells. The results demonstrated that MSC-derived exosomes significantly down-regulated the expression of vascular endothelial growth factor (VEGF) in tumor cells, which lead to inhibition of angiogenesis in vitro and in vivo. Additionally, miR-16, a miRNA known to target VEGF, was enriched in MSC-derived exosomes and it was partially responsible for the anti-angiogenic effect of MSC-derived exosomes. The collective results suggest that MSC-derived exosomes may serve as a significant mediator of cell-to-cell communication within the tumor microenvironment and suppress angiogenesis by transferring anti-angiogenic molecules. Citation Format: Sae-Ra Park. Exosomes derived from mesenchymal stem cells suppress angiogenesis by down-regulating VEGF expression in breast cancer cells. [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 170. doi:10.1158/1538-7445.AM2014-170

Suppression of vascular endothelial growth factor abrogates the immunosuppressive capability of murine gastric cancer cells and elicits antitumor immunity.

The mechanisms underlying immune evasion by gastric cancer have not been well described due to a lack of gastric tumor models in immunocompetent mice. In the current study, we found that supernatants from MFC cells, a murine gastric cancer line, inhibited the lipopolysaccharide (LPS) induced maturation and cross-presentation of bone-marrow-derived dendritic cells (BMDCs). Moreover, MFC tumor-derived factors markedly altered the cytokine profiles of BMDCs, leading to a trend of increased levels of interleukin 4 (IL4), IL6, IL23 and transforming growth factor β, as well as decreased levels of tumor necrosis factor α. qPCR and ELISA revealed that MFC cells expressed a high level of vascular endothelial growth factor (VEGF). Downregulating VEGF expression abrogated the inhibitory effect of MFC-derived factors on the maturation and cross-presentation of BMDCs. In addition, VEGF knockdown greatly impaired the tumorigenicity of MFC cells in immunocompetent mice. Compared with parental MFC tumors, VEGF-low MFC tumors grew much more slowly and the survival of tumor-inoculated mice was significantly improved. More importantly, mice rejecting inoculated VEGF-low MFC tumor cells gained resistance to re-challenged parental tumors, which was attributed to an antitumor immunity response against parental MFC tumors. These results reveal an immunosuppressive role for VEGF in murine gastric cancer.

Role of miR-146a in human chondrocyte apoptosis in response to mechanical pressure injury in vitro.

MicroRNA (miR)-146a is known to be overexpressed in osteoarthritis (OA). However, the role of miR-146a in OA has not yet been fully elucidated. In the present study, we applied mechanical pressure of 10 MPa to human chondrocytes for 60 min in order to investigate the expression of miR-146a and apoptosis following the mechanical pressure injury. Normal human chondrocytes were transfected with an miR-146a mimic or an inhibitor to regulate miR-146a expression. Potential target genes of miR-146a were predicted using bioinformatics. Moreover, luciferase reporter assay confirmed that Smad4 was a direct target of miR-146a. The expression levels of miR-146a, Smad4 and vascular endothelial growth factor (VEGF) were quantified by quantitative reverse transcription PCR and/or western blot analysis. The effects of miR-146a on apoptosis were detected by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) flow cytometry. The results indicated that mechanical pressure affected chondrocyte viability and induced the early apoptosis of chondrocytes. Mechanical pressure injury increased the expression levels of miR-146a and VEGF and decreased the levels of Smad4 in the chondrocytes. In the human chondrocytes, the upregulation of miR-146a induced apoptosis, upregulated VEGF expression and downregulated Smad4 expression. In addition, the knockdown of miR-146a reduced cell apoptosis, upregulated Smad4 expression and downregulated VEGF expression. Smad4 was identified as a direct target of miR-146a by harboring a miR-146a binding sequence in the 3′-untranslated region (3′-UTR) of its mRNA. Furthermore, the upregulation of VEGF induced by miR-146a was mediated by Smad4 in the chondrocytes subjected to mechanical pressure injury. These results demonstrated that miR-146a was overexpressed in our chondrocyte model of experimentally induced human mechanical injury, accompanied by the upregulation of VEGF and the downregulation of Smad4 in vitro. Moreover, our data suggest that miR-146a is involved in human chondrocyte apoptosis in response to mechanical injury, and may contribute to the mechanical injury of chondrocytes, as well as to the pathogenesis of OA by increasing the levels of VEGF and damaging the transforming growth factor (TGF)-β signaling pathway through the targeted inhibition of Smad4 in cartilage.

Protective effect of lycopene against diabetic retinopathy in rats and the related mechanism

Objective To study the protective effect of lycopene(LP)against diabetic retinopathy(DR)in rats and its related mechanism.Methods A single dose of streptozotocin(56mg/kg)was injected intraperitoneally in SD rats to induce diabetes retinopathy(DR),and the 20 successful DR models were equally randomized into DR group and LP treatment group.Meanwhile,10 normal rats served as normal control group(NC).LP group received LP gavage(60mg/kg)once a day;NC and DR groups were gavaged with equivalent saline daily for 8weeks.The serum levels of endothelin(ET)and calcitonin gene related protein(CGRP)were detected by using radioimmunoassay(RIA),and the expression of vascular endothelial growth factor(VEGF)in the retina was determined by immunohistochemistry and Western blotting analysis.Results The serum levels of ET and expression of VEGF in the retina were significantly increased in DR groups when compared with NC group(P0.05),and the serum CGRP was significantly decreased(P0.05);Compared with DR group,LP group had significantly lower VEGF expression and ET levels and significantly higher level of CGRP(P0.05).Conclusion LP can protect against DR in rats by decreasing serum ET,increasing serum CGRP,and subsequent down-regulating VEGF expression.

Exosomes derived from mesenchymal stem cells suppress angiogenesis by down-regulating VEGF expression in breast cancer cells.

Exosomes are small membrane vesicles released by a variety of cell types. Exosomes contain genetic materials, such as mRNAs and microRNAs (miRNAs), implying that they may play a pivotal role in cell-to-cell communication. Mesenchymal stem cells (MSCs), which potentially differentiate into multiple cell types, can migrate to the tumor sites and have been reported to exert complex effects on tumor progression. To elucidate the role of MSCs within the tumor microenvironment, previous studies have suggested various mechanisms such as immune modulation and secreted factors of MSCs. However, the paracrine effects of MSC-derived exosomes on the tumor microenvironment remain to be explored. The hypothesis of this study was that MSC-derived exosomes might reprogram tumor behavior by transferring their molecular contents. To test this hypothesis, exosomes from MSCs were isolated and characterized. MSC-derived exosomes exhibited different protein and RNA profiles compared with their donor cells and these vesicles could be internalized by breast cancer cells. The results demonstrated that MSC-derived exosomes significantly down-regulated the expression of vascular endothelial growth factor (VEGF) in tumor cells, which lead to inhibition of angiogenesis in vitro and in vivo. Additionally, miR-16, a miRNA known to target VEGF, was enriched in MSC-derived exosomes and it was partially responsible for the anti-angiogenic effect of MSC-derived exosomes. The collective results suggest that MSC-derived exosomes may serve as a significant mediator of cell-to-cell communication within the tumor microenvironment and suppress angiogenesis by transferring anti-angiogenic molecules.

Experimental Study of Endostar Injection Concomitant with Cryoablation on Lung Adenocarcinoma A549 Xenografts

To explore the inhibiting effect and mechanism of Endostar injection concomitant with cryoablation on lung adenocarcinoma A549 xenografts in nude mice. A total of 24 nude mice with subcutaneous xenografts of the A549 cell line were established and divided into 4 groups when the maximal diameters of tumors became 1 cm: control group, Endostar group, cryoablation group and combination group (Endostar concomitant with cryoablation). The nude mice were sacrificed after 21-days treatment, tumour tissues were removed to measure their volume, in situ test of TdT-mediated dUTP nick end labeling (TUNEL) was adopted to determine the cellular apoptosis around freezing injury zones, and immunohistochemical SP test was applied for the detection of micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression levels. At 21-days after treatment, the growth velocities of control group, Endostar group, cryoablation group and combination group were 236.7 ± 51.2%, 220.0 ± 30.6%, 159.5 ± 29.3% and 103.3 ± 25.5% (P<0.01), while cellular apoptosis rates of tumors were 21.7 ± 2.34%, (22.17 ± 1.47)%, 38.3 ± 1.37% and 49.2 ± 1.72%, (P<0.01), respectively, according to the immunohistochemical test. MVD and VEGF expression levels in the combination group were both lower than in other groups (P<0.01), also being positively related (r=0.925, P<0.01). Endostar can significantly improve the inhibitory effects of cryoablation on xenografts of lung adenocarcinoma A549, and the mechanism is probably associated with its function as an inhibitor of tumour neo-angiogenesis through down-regulating VEGF expression.

Suppression of metastasis of human pancreatic cancer cells to the liver by small interfering RNA-mediated targeting of the midkine gene

The present study aimed to ascertain whether suppression of midkine (MK) expression in pancreatic cancer cells inhibits metastasis to the liver. Human pancreatic cancer AsPC-1 cells were transfected with small interfering RNA (siRNA) targeting MK. siRNA against MK was observed to reduce the expression of MK mRNA and protein in a concentration- and time-dependent manner, and to decrease the number of migrating and tissue-penetrating cells in a concentration-dependent manner (P<0.005). Extracellular vascular endothelial growth factor (VEGF) concentrations were markedly reduced for the siRNA-transfected cells compared with those that were non-siRNA-transfected. The liver transmission rate and tumor nodule number in the animals harboring the siRNA-transfected cells were lower compared with those in the animals harboring the non-siRNA-transfected cells (P<0.005). These data indicate that metastasis of pancreatic cancer cells to the liver requires the expression of MK. The downregulation of VEGF expression is essential to the mechanism whereby suppression of MK expression constrains the metastasis of pancreatic cancer cells to the liver.

Small interference RNA targeting vascular endothelial growth factor gene effectively attenuates retinal neovascularization in mice model

Background The mechanism of retinal neovascularization is not understood completely. Many growth factors are involved in the process of retinal neovascularization, such as vascular endothelial growth factor (VEGF) and pigment epithelium-deprived factor (PEDF), which are the representatives of angiogenic and antiangiogenic molecules respectively. Oxygen induced retinopathy (OIR) is a useful model to investigate retinal neovascularization. The present study was conducted to investigate the feasibility of small interference RNA (siRNA) targeting VEGF gene in attenuating oxygen induced retinopathy (OIR) by regulating VEGF to PEDF ratio (VEGF/PEDF). Methods In vitro, cultured EOMA cells were transfected with VEGF-siRNA (psi-HITM/EGFP/VEGF siRNA) and LipofectamineTM 2000 for 24, 48, and 72 hours, respectively. Expression of VEGF mRNA was evaluated by real time polymerase chain reaction (PCR) and the level of VEGF protein was analyzed by Western blotting. In vivo, OIR model mice were established, the mice (C57BL/6J) received an intra-vitreal injection of 1 μl of mixture of psi-HITM/EGFP/VEGF siRNA and Lipofectamine 2000. Expressions of retinal VEGF and PEDF protein were measured by Western blotting, retinal neovascularization was observed by fluorescein angiography, and quantified. Results In vitro psi-HITM/EGFP/VEGF siRNA treatment significantly reduced VEGF mRNA and protein expression. In vivo, with decreased VEGF and VEGF-PEDF ratio, significant attenuation of neovascular tufts, avascular regions, tortuous, and dilated blood vessels were observed in the interfered animals. Conclusions VEGF plays an important role in OIR, and the transfection of VEGF-siRNA can effectively downregulate VEGF expression in vivo, accompanied by the downregulation of VEGF-PEDF ratio, and simultaneous attenuation of retinal neovascularization was also observed. These findings suggest that VEGF/PEDF may serve as a potential target in the treatment of retinal neovascularization and RNA interference targeting VEGF expression, which represents a possible therapeutic strategy.

P53 promotes VEGF expression and angiogenesis in the absence of an intact p21-Rb pathway

There is growing evidence that the p53 tumour suppressor downregulates vascular endothelial growth factor (VEGF) expression, although the underlying mechanisms remain unclear and controversial. Here we provide insights from in vitro experiments and in vivo xenotransplantation assays that highlight a dual role for p53 in regulating VEGF during hypoxia. Unexpectedly, and for the first time, we demonstrate that p53 rapidly induces VEGF transcription upon hypoxia exposure by binding, in an HIF-1α-dependent manner, to a highly conserved and functional p53-binding site within the VEGF promoter. However, during sustained hypoxia, p53 indirectly downregulates VEGF expression via the retinoblastoma (Rb) pathway in a p21-dependent manner, which is distinct from its role in cell-cycle regulation. Our findings have important implications for cancer therapy, especially for tumours that harbour wild-type TP53 and a dysfunctional Rb pathway.

Branched‐chain amino acid deficiency stabilizes insulin‐induced vascular endothelial growth factor mRNA in hepatocellular carcinoma cells

Abnormal sugar metabolism is closely related to chronic liver diseases, including hepatocellular carcinoma (HCC). We previously reported that fasting hyperinsulinemia is a poor prognostic factor for HCC patients. A recent large-scale study has shown that long-term administration of branched chain amino acids (BCAA) reduces the risk of HCC development in obese cirrhotic patients who have been diagnosed with diabetes mellitus, although the mechanism by which it does so is unclear. In this study, we analyzed the expression of vascular endothelial growth factor (VEGF) in HepG2 cells under high-insulin culture conditions, and examined the effect of BCAA on VEGF expression. VEGF secretion was significantly increased by 200 nM of insulin under BCAA deficient conditions, but it was repressed by the addition of BCAA. BCAA activated the mTOR pathway and increase HIF-1α expression under high-insulin culture conditions, however quantitative PCR analysis showed that insulin-induced expression of VEGF mRNAs (VEGF121 and VEGF165) decreased 2 h after the addition of BCAA. The half-lives of both VEGF121 and 165 mRNAs were shortened in the presence of BCAA compared to the absence of BCAA. Therefore it is thought that BCAA regulate VEGF expression mainly at the post-transcriptional level. We also examined which of the Valine, Leucine, and Isoleucine components of BCAA were essential for VEGF mRNA degradation. All three BCAA components were required for acceleration of insulin-induced VEGF mRNA degradation. These results suggest that administration of BCAA may downregulate VEGF expression in patients who have hyperinsulinemia and are in the process of developing HCC.

Induced apoptosis in human prostate cancer cells by blocking of vascular endothelial growth factor by siRNA

Vascular endothelial growth factor (VEGF) regulates several cell functions including; proliferation, differentiation, permeability, vascular tone, and the production of vasoactive molecules. The purpose of this study was to evaluate the potency of specific short-interfering RNA (siRNA) to suppress human VEGF expression by siRNA and investigate the effects of VEGF down-regulation on the cell proliferation and apoptosis of the human prostate cancer cell lines DU-145. Transfection was performed using X-tremeGENE siRNA transfection reagent. At different time intervals, transfected cells were harvested and total RNA was extracted for RT-PCR. The VEGF content in supernatants were measured by ELISA. Inhibition of cell growth by hVEGF-siRNA was measured by using cell proliferation ELISA BrdU assay. Apoptotic cells were evaluated by using annexin-V-FITC apoptotic detection method. Transfection of hVEGF-siRNA resulted in statistically significant inhibition of hVEGF-mRNA that in turn caused a marked reduction in the expression of hVEGF. The cell growth was assessed every 24 h for 4 days after siRNA treatment resulted in a marked inhibition of cell proliferation as compared to scramble siRNA. The results of apoptosis showed that approximately 15 % of the cells treated with control-siRNA manifested evident apoptotic changes after 24 hpt, whereas DU-145 cells treated with hVEGF-siRNA significantly were positive, that is to say, 53 % at 72 hpt 23.9 ± 2.78 % (P < 0.001) and 13 ± 1.57 % at 96 hpt. Our findings indicate that siRNA are effective in eliciting the RNAi pathway in cancerous cells and that specific siRNA efficiently down-regulate VEGF expression. They could decrease VEGF production and induce apoptosis, which may also be linked to the inhibition of cancerous cell proliferation. Therefore, it can be concluded that siRNA-mediated suppression of VEGF represents a powerful tool against prostate cancer cell proliferation. VEGF down-regulation exerts a direct anti-apoptotic function in the DU-145 cell lines and promises the development of drugs for cancer therapy.

Recombinant human endostatin inhibits adjuvant arthritis by down-regulating VEGF expression and suppression of TNF-α, IL-1β production

The aim of this study was to examine the effect of recombinant human endostatin (rhEndostatin) on adjuvant arthritis (AA) in rats and its possible mechanisms. RhEndostatin was subcutaneously administrated to AA rats after immunization. The progression of AA was assessed by the macroscopic arthritis scoring system of paws. Histological examination of the synovial tissues was examined by hematoxylin and eosin staining. The expression level of vascular endothelial growth factor (VEGF) mRNA and proteins in the synovial tissues was evaluated by realtime PCR and immunohistochemistry, respectively. Fibroblast-like synoviocytes (FLS) were isolated from synovial tissues. Cell proliferation assay was evaluateded with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. The levels of tumour necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) in culture medium was examined by radioimmno assay. RhEndostatin attenuated the severity of arthritis on both second hind paw volume and polyarthritis score, as well as improved the arthritic status histologically in AA rats. Simultaneously, rhEndostatin can inhibit the expression of VEGF in synovial tissues. The proliferation of FLS and TNF-α, IL-1β production from culture medium was significantly inhibited by rhEndostatin. Our data suggest that rhEndostatin inhibits adjuvant arthritis by down-regulating VEGF expression and suppression of TNF-α, IL-1β production.

MicroRNA-145 targets vascular endothelial growth factor and inhibits invasion and metastasis of osteosarcoma cells

MicroRNAs are important gene regulators that play a profound role in tumorigenesis. MicroRNA-145 (miR-145), an important member in the family of microRNAs, is under-expressed in several types of tumors and acts as a tumor suppressor. The role and probable pathways of miR-145 in osteosarcoma carcinogenesis are still unknown. In this study, we found that miR-145 was significantly under-expressed in osteosarcoma tissues, and the over-expression of miR-145 could inhibit invasion and angiopoiesis of osteosarcoma cells. Furthermore, the results showed that vascular endothelial growth factor (VEGF) expression was down-regulated in osteosarcoma cells after miR-145 transfection. On the basis of these results, we performed the luciferase assay and verified that miR-145 could down-regulate VEGF at the translational level by partially binding to VEGF 3' untranslated region (3'UTR). Therefore, it can be concluded that miR-145 can inhibit invasion and metastasis of osteosarcoma cells. One of the mechanisms is the down-regulation of VEGF expression by miR-145 by binding to the 3'UTR of VEGF mRNA specifically. These novel findings may have extensive implications for an effective gene therapy of osteosarcoma.

Inhibition of experimental corneal neovascularization by exogenous mouse interferon-inducible protein-10

Background It has been proved that as a chemokine,interferon-inducible protein-10(IP-10)can regulate the immuno-inflammatory reaction.Some new researches showed that IP-10 also played role in regulating the neovascular vessel formation.Corneal neovascularization (CNV) is associated with multiple cellular factors,but its mechanism is below clear. Objective The present study was to address the roles of exogenous mouse IP-10 in alkali burn-induced CNV. Methods Eighty-two SPF BALB/c mice were used in this experiment and grouped according to random number table.The corneal alkali burn models were established by putting the filter paper with 1 mol/L NaOH at the central corneas of the left eyes for 40 seconds.10 mg/L IP-10 was topically administered from the first day or 14 days after modeling in the early intervene group( 10 eyes)or middle-late intervene group(5 eyes).CNV area was measured as a percentage of whole cornea.0.2％ sodium hyaluronate(HA) as vehicle was utilized in the model control group.Angiogenic factor expression in corneal tissue in the early intervene group was quantified by reverse transcriptase polymerase chain reaction (RT-PCR)and compared with model control group.All animal experiments were performed in accordance with the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research and complied with the standards of Guidelines for the Care and Use of Laboratory Animals of Soochow University. Results The CNV percentage was(88.67±10.22) ％ in the model control mice,showing a significant increase in comparison with that of IP-10 early intervene group (70.06±12.21)％ (t=3.77,P=0.00).In 21 days after corneal alkali burn,the CNV percentage was(87.33±13.47)％ in the model control mice,and that of the IP-10 middle-late intervene group was ( 86.56± 12.47 ) ％ without significant difference between them ( t =1.26,P＞0.05 ).Two days or four days after IP-10 early intervene,the expressions of chemokine receptor type 3 ( CXCR3 ) in corneal tissue were significant higher than model control group( t =3.13,3.07,P＜0.05 ),but the expressions of vascular endothelial growth factor (VEGF) in cornea were lowed ( t =5.99,6.27,P＜0.01),and so were transforming growth factor-β1 (TGF-β1) (t =8.50,P＜0.01;t =4.53,P＜0.05).Conclusions The early topical administration of the exogenous mouse IP-10 can inhibit CNV by up-regulating CXCR3 expression and down-regulating VEGF and TGF-β1 expression in cornea.However,middle-later usage of the IP-10 is uneffective. Key words: Interferon-inducible protein-10; Corneal alkali burn; Corneal neovascularization

SiRNA‐Mediated Down‐regulation of Vascular Endothelial Growth Factor in MCF‐7 cells

Vascular endothelial growth factor (VEGF) promotes angiogenesis and vascularization. Inhibition of angiogenesis results in tumor regression. VEGF induces endothelial cell proliferation, promotes cell migration, and inhibits apoptosis. Deregulated VEGF expression contributes to angiogenesis and tumor growth and the etiology of several other diseases that are characterized by abnormal angiogenesis. VEGF family of genes include VEGF‐A, VEGF‐B, VEGF‐C and VEGF‐D. To investigate targeted degradation of VEGF mRNA using short interference RNA (siRNA) as a means to inhibit VEGF expression, MCF‐7 human breast cancer cells were transfected with phosphothioester siRNAs designed to degrade VEGF mRNAs. RNA was extracted by NP‐40 lysis method and analyzed by Reverse Transcription‐Polymerase Chain Reaction (RT‐PCR) and Northern blotting. Western blot analysis was performed on whole cell lysates. RT‐PCR and Northern blot analysis showed siRNA‐mediated degradation of VEGF mRNA. Western blot analysis showed a corresponding decrease in the expression of VEGF. The above results indicate the potential use of siRNA for the down regulation of VEGF expression and consequently cause tumor regression. This work was supported by science research funds from Arnold and Marie Schwartz College of Pharmacy, Long Island University, Brooklyn, NY.

Copper Deficiency Induced Emphysema Is Associated with Focal Adhesion Kinase Inactivation

BackgroundCopper is an important regulator of hypoxia inducible factor 1 alpha (HIF-1α) dependent vascular endothelial growth factor (VEGF) expression, and is also required for the activity of lysyl oxidase (LOX) to effect matrix protein cross-linking. Cell detachment from the extracellular matrix can induce apoptosis (anoikis) via inactivation of focal adhesion kinase (FAK).MethodologyTo examine the molecular mechanisms whereby copper depletion causes the destruction of the normal alveolar architecture via anoikis, Male Sprague-Dawley rats were fed a copper deficient diet for 6 weeks while being treated with the copper chelator, tetrathiomolybdate. Other groups of rats were treated with the inhibitor of auto-phosphorylation of FAK, 1,2,4,5-benzenetetraamine tetrahydrochloride (1,2,4,5-BT) or FAK small interfering RNA (siRNA).Principal FindingsCopper depletion caused emphysematous changes, decreased HIF-1α activity, and downregulated VEGF expression in the rat lungs. Cleaved caspase-3, caspase-8 and Bcl-2 interacting mediator of cell death (Bim) expression was increased, and the phosphorylation of FAK was decreased in copper depleted rat lungs. Administration of 1,2,4,5-BT and FAK siRNA caused emphysematous lung destruction associated with increased expression of cleaved capase-3, caspase-8 and Bim.ConclusionsThese data indicate that copper-dependent mechanisms contribute to the pathogenesis of emphysema, which may be associated with decreased HIF-1α and FAK activity in the lung.

Downregulating hypoxia‐inducible factor‐2α improves the efficacy of doxorubicin in the treatment of hepatocellular carcinoma

The hypoxic microenvironment inside solid tumors, including hepatocellular carcinoma (HCC), is a major cause of tumor resistance to chemotherapy. The recently identified hypoxia-inducible factor (HIF)-2 executes the hypoxia response. Its expression feature and transcriptional targets indicate a possible dominance of HIF-2 in regulating genes in HCC. The aim of the present study was to determine whether transfection of siRNA targeting HIF-2α could enhance the efficacy of doxorubicin, the most commonly used drug in the treatment of HCC. Transfection of HIF-2 siRNA into human HCC cells downregulated the expression of HIF-2α, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-α, and cyclin D1, but had little effect on the expression of HIF-1α, fms-related tyrosine kinase-1 (Flt-1), the glucose transporter (GLUT)-1, and lactate dehydrogenase A (LDHA). Doxorubicin itself only downregulated VEGF expression. Furthermore, HIF-2 siRNA inhibited proliferation, induced cell cycle arrest at the G(0)/G(1) phase, and acted synergistically with doxorubicin to inhibit the growth of human HCC cells in vitro. Transfection of HIF-2 siRNA also downregulated tumoral expression of HIF-2α, VEGF, TGF-α, and cyclin D1 in vivo, and acted synergistically with doxorubicin to suppress the growth of HepG2 tumors established in immunodeficient mice by inhibiting cell proliferation, tumor angiogenesis and microvessel perfusion. The results of the present study suggest that targeting HIF-2α with siRNA warrants investigation as a potential strategy to enhance the efficacy of doxorubicin in the treatment of HCC.