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Molecular changes induced by melanoma cell conditioned medium (MCM) in HUVEC cells.

ABSTRACT: Malignant melanoma is a complex genetic disease and the most aggressive form of skin cancer. Melanoma progression and metastatic dissemination fundamentally relies on the process of angiogenesis. Melanomas produce an array of angiogenic modulators that mediate pathological angiogenesis. Such tumor-associated modulators arbitrate the enhanced proliferative, survival and migratory responses exhibited by endothelial cells, in the hypoxic tumor environment. The current study focuses on melanoma-induced survival of endothelial cells under hypoxic conditions. Melanoma conditioned media were capable of enabling prolonged endothelial cell survival under hypoxia, in contrast with the conditioned media derived from melanocytes, breast and pancreatic tumors. To identify the global changes in gene expression and further characterize the pro-survival pathway induced in endothelial cells, we performed microarray analysis on endothelial cells treated with melanoma conditioned medium under normoxic and hypoxic conditions.

ORGANISM(S): Homo sapiens

PROVIDER: GSE33115 | GEO | 2013/09/30

SECONDARY ACCESSION(S): PRJNA149359

REPOSITORIES: GEO

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Project description:Pathologic retinal neovascularization is a potentially blinding consequence seen in many common diseases including diabetic retinopathy, retinopathy of prematurity, and retinal vascular occlusive diseases, among others. The use of therapeutics targeting pro-angiogenesis factors such as vascular endothelial growth factor (VEGF) has proven to be highly effective, however considerable side effects exist and serial anti-VEGF treatment has been shown to decrease effectiveness over time. Characterization of additional regulators of neovascularization is needed to further understand neovascular disease and identify possible new therapeutic targets. This study investigates epithelial membrane protein 2 (EMP2) and its role as a possible modulator of angiogenesis in human retinal pigment epithelium (RPE) under hypoxia. EMP2 is highly expressed in human RPE and RPE cell lines. Adult retinal pigment epithelial cell line-19 (ARPE-19) cells were genetically modified to either overexpress EMP2 (OE) or knock down EMP2 (KD) and expression at the RNA and protein level was evaluated using RNA sequencing and western blot respectively. Protein expression was evaluated under both normoxic conditions and conditions of hypoxic stress with 0.5% O2. EMP2 expression was found to positively correlate with expression of the pro-angiogenesis factors hypoxia inducible factor 1-alpha (HIF-1a) and VEGF for both RNA and protein. EMP2 mediated changes in ARPE-19 cells was also found to alter the secretion of a paracrine factor(s) in conditioned media that can regulate human umbilical vein endothelial cells (HUVEC) endothelial cell migration and capillary tube formation in in vitro functional angiogenesis assays. This study identifies EMP2 as a potentially important mediator of angiogenesis in the human RPE, a tissue involved in abnormal retinal neovascularization in a number of diseases. EMP2 levels positively correlate with those of the potent pro-angiogenesis mediators HIF-1a and VEGF, however the mechanism of this relationship remains to be clarified. This study supports further investigation of EMP2 as a promising novel target for therapeutic treatment of pathologic neovascularization in the retina.

Project description:Abstract: Background & Aims: Unusual hypervascularity is a hallmark of human hepatocellular carcinoma (HCC). Although microRNA-214 (miR-214) is upregulated in other human cancers, it is downregulated in HCC. We elucidated the biological and clinical significance of miR-214 downregulation in HCC. Methods: MicroRNAs deregulated in HCC were identified using array-based MicroRNA profiling. A luciferase reporter assay confirmed target association between miR-214 and hepatoma-derived growth factor (HDGF). Tube formation and in vivo angiogenesis assays validated the roles of miR-214/HDGF in angiogenesis. Results: MiR-214 downregulation was associated with higher tumor recurrence and worse clinical outcomes. Ectopic expression of miR-214 suppressed xenograft tumor growth and microvascularity of the tumor and its surrounding tissues. The genes downregulated by ectopic expression of miR-214 were involved in the regulation of apoptosis, cell cycle, and angiogenesis. Integrated analysis disclosed HDGF as a downstream target of miR-214. Conditioned medium of HCC cells contained bioactivity to stimulate tube formation of human umbilical vein endothelial cells, which was abolished by pretreatment of the conditioned media with HDGF antibodies, silencing of HDGF expression or ectopic expression of miR-214 in the donor HCC cells. The angiogenic activity of the conditioned media lost by ectopic expression of miR-214 in the donor cells was restored by supplementation with recombinant HDGF. In vivo tumor angiogenesis assays showed significant suppression of tumor vascularity by ectopic expression of miR-214. Conclusions: A novel role of microRNA in tumrigenesis is identified. Downregulation of miR-214 contributes to unusual hypervascularity of HCC via activation of the HDGF paracrine pathway for tumor angiogenesis. To identify miRNAs that are deregulated in human HCC, 68 HCC and 21 non-tumor liver tissues were subjected to profiling of miRNA expression using miRNA arrays containing 739 human miRNA probes. Differentially expressed microRNAs were identified.

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Molecular changes induced by melanoma cell conditioned medium (MCM) in HUVEC cells.

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