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Erythropoietin Receptor Contributes to Melanoma Cell Survival in vivo

Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Oncogene (Impact Factor: 8.56). 08/2011; 31(13):1649-60. DOI: 10.1038/onc.2011.366
Source: PubMed

ABSTRACT Erythropoietin (Epo) is widely used clinically to treat anemia associated with various clinical conditions including cancer. Data from several clinical trials suggest significant adverse effect of Epo treatment on cancer patient survival. However, controversy exists whether Epo receptor (EpoR) is functional in cancer cells. In this study, we demonstrated that EpoR mRNA expression was detectable in 90.1% of 65 melanoma cell lines, and increased copy number of the Epo and EpoR loci occurred in 30 and 24.6% of 130 primary melanomas, respectively. EpoR knockdown in melanoma cells resulted in diminished ERK phosphorylation in response to Epo stimulation, decreased cell proliferation and increased response to the inhibitory effect of hypoxia and cisplatin in vitro. EpoR knockdown significantly decreased melanoma xenograft size and tumor invasion in vivo. On the contrary, constitutive activation of EpoR activated cell proliferation pathways in melanoma cells and resulted in increased cell proliferation and resistance to hypoxia and cisplatin treatment in vitro. EpoR activation resulted in significantly larger xenografts with increased tumor invasion of surrounding tissue in vivo. Daily administration of recombinant Epo fails to stimulate melanoma growth in vivo, but the treatment increased vascular size in the xenografts. Increased local recurrence after excision of the primary tumors was observed after Epo treatment. Epo induced angiogenesis in Matrigel plug assays, and neutralization of Epo secreted by melanoma cells results in decreased angiogenesis. These data support that EpoR is functional in melanoma and EpoR activation may promote melanoma progression, and suggest that Epo may stimulate angiogenesis and increase survival of melanoma cells under hypoxic condition in vivo.

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    • "However, the functional role of EPO in tumor biology is still far from being fully understood. In spite of a growing amount of in vitro and in vivo studies (Shi et al. 2010; Kumar et al. 2011) that associate the presence of EpoR with the promotion of cancer cells proliferation and invasion, a linear correlation between EpoR activation and an efficient responsiveness to exogenous EPO administration has not been established. At the bedside, the therapeutic benefit of the clinical use of erythropoiesis-stimulating agents in cancer is still a delicate controversial discussion point. "
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    ABSTRACT: It has been recently shown that the biological effects of erythropoietin (EPO) are not limited to the hematopoietic compartment but, as pleiotropic glycoprotein, this hormone can exert pro-angiogenic and tissue-protective functions also in a wide range of non-hematopoietic organs. The role of EPO and the effective functionality of its receptor in solid tumors are still a controversial point of debate. In the present work we analyzed the gene expression of EPO and its cognate receptor (EpoR) in a rat model of thioacetamide-induced damage and tumor. An analysis of the EPO/EpoR axis was also performed on human cholangiocarcinoma (CC) cell lines. A progressive increase of EPO and EpoR mRNA can already be observed during the fibrotic–cirrhotic development with a peak of expression rising at tumor formation (24.7 ± 9.9-fold increase and 15.5 ± 1.1-fold increase, respectively, for the two genes). Co-localization studies by immunofluorescence revealed hepatocytes in the regenerative cirrhotic nodules (Hep Par-1+) and in the dysplastic bile duct cells (CK19+) as the major EPO producers in this specific condition. The same cell populations, together with endothelial cells, exhibited an increased expression of EpoR, although all the non-parenchymal cell populations in the liver exhibited modest basal mRNA levels. Challenging human CC cells, Mz-Cha-2, with a combination of EPO and SCF resulted in a synergistic effect on the gene expression of EPO, CyclinD1 and PCNA. This study suggests that the autocrine and paracrine release of endogenous EPO in the microenvironment may contribute to the development and maintenance of the CC possibly in cooperation with other signaling pathways. Electronic supplementary material The online version of this article (doi:10.1007/s00418-012-1037-x) contains supplementary material, which is available to authorized users.
    Histochemie 10/2012; 139(3). DOI:10.1007/s00418-012-1037-x · 2.93 Impact Factor
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    • "Similar findings were found in ovarian carcinoma A2780 cell with down-regulated EpoR, in which p-AKT increased for compensatory mechanisms [25]. In melanoma cells, EpoR down-regulation resulted in diminished p-Erk in response to Epo stimulation [29]. Further investigations are needed to disclose other functions of EpoR in RCC cells. "
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    ABSTRACT: Co-expression of erythropoietin (Epo) and erythropoietin receptor (EpoR) has been found in various non-hematopoietic cancers including hereditary and sporadic renal cell carcinomas (RCC), but the Epo/EpoR autocrine and paracrine mechanisms in tumor progression have not yet been identified. In this study, we used RNA interference method to down-regulate EpoR to investigate the function of Epo/EpoR pathway in human RCC cells. Epo and EpoR co-expressed in primary renal cancer cells and 6 human RCC cell lines. EpoR signaling was constitutionally phosphorylated in primary renal cancer cells, 786-0 and Caki-1 cells, and recombinant human Epo (rhEpo) stimulation had no significant effects on further phosphorylation of EpoR pathway, proliferation, and invasiveness of the cells. Down-regulation of EpoR expression in 786-0 cells by lentivirus-introduced siRNA resulted in inhibition of growth and invasiveness in vitro and in vivo, and promotion of cell apoptosis. In addition, rhEpo stimulation slightly antagonized the anti-tumor effect of Sunitinib on 786-0 cells. Sunitinib could induce more apoptotic cells in 786-0 cells with knockdown EpoR expression. Our results suggested that Epo/EpoR pathway was involved in cell growth, invasion, survival, and sensitivity to the multi-kinases inhibitor Sunitinib in RCC cells.
    PLoS ONE 09/2012; 7(9):e45122. DOI:10.1371/journal.pone.0045122 · 3.23 Impact Factor
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    • "The present study was driven by the controversy regarding the benefits of treatment of cancer patients with erythropoiesis stimulating reagents, for example, multiple myeloma patients (Mittelman et al, 2004), vs the possible hazards of such treatment in patients with certain solid tumours, for example, head and neck and melanoma (Abhold et al, 2011; Kumar et al, 2011), respectively. Our results show for the first time that application of EPO caused activation of PARP proteins including PARP-1, and that polyADP-ribosylation subsequently mediated EPO-induced histone H4 acetylation and expression of c-fos and Egr-1 that mediate EPO-induced proliferation (Erickson-Miller et al, 2000). "
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    ABSTRACT: Background: Recombinant human erythropoietin (EPO) is the leading biotechnology engineered hormone for treatment of anaemia associated with chronic conditions including kidney failure and cancer. The finding of EPO receptors on cancer cells has raised the concern that in addition to its action in erythropoiesis, EPO may promote tumour cell growth. We questioned whether EPO-induced signalling and consequent malignant cell manifestation is mediated by polyADP-ribosylation. Methods: Erythropoietin-mediated PARP (polyADP-ribose polymerase-1) activation, gene expression and core histone H4 acetylation were examined in UT7 cells, using western blot analysis, RT–PCR and immunofluorescence. Erythropoietin-driven migration of the human breast epithelial cell line MDA-MB-435 was determined by the scratch assay and in migration chambers. Results: We have found that EPO treatment induced PARP activation. Moreover, EPO-driven c-fos and Egr-1 gene expression as well as histone H4 acetylation were mediated via polyADP-ribosylation. Erythropoietin-induced cell migration was blocked by the PARP inhibitor, ABT-888, indicating an essential role for polyADP-ribosylation in this process. Conclusions: We have identified a novel pathway by which EPO-induced gene expression and breast cancer cell migration are regulated by polyADP-ribosylation. This study introduces new possibilities regarding EPO treatment for cancer-associated anaemia where combining systemic EPO treatment with targeted administration of PARP inhibitors to the tumour may allow safe treatment with EPO, minimising its possible undesirable proliferative effects on the tumour.
    British Journal of Cancer 09/2012; 107(8):1317-26. DOI:10.1038/bjc.2012.395 · 4.82 Impact Factor
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