| 1. |
- Berta, Judit, et al.
(author)
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Apelin promotes blood and lymph vessel formation and the growth of melanoma lung metastasis
- 2021
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Journal article (peer-reviewed)abstract
- Apelin, a ligand of the APJ receptor, is overexpressed in several human cancers and plays an important role in tumor angiogenesis and growth in various experimental systems. We investigated the role of apelin signaling in the malignant behavior of cutaneous melanoma. Murine B16 and human A375 melanoma cell lines were stably transfected with apelin encoding or control vectors. Apelin overexpression significantly increased melanoma cell migration and invasion in vitro, but it had no impact on its proliferation. In our in vivo experiments, apelin significantly increased the number and size of lung metastases of murine melanoma cells. Melanoma cell proliferation rates and lymph and blood microvessel densities were significantly higher in the apelin-overexpressing pulmonary metastases. APJ inhibition by the competitive APJ antagonist MM54 significantly attenuated the in vivo pro-tumorigenic effects of apelin. Additionally, we detected significantly elevated circulating apelin and VEGF levels in patients with melanoma compared to healthy controls. Our results show that apelin promotes blood and lymphatic vascularization and the growth of pulmonary metastases of skin melanoma. Further studies are warranted to validate apelin signaling as a new potential therapeutic target in this malignancy.
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| 2. |
- Rozsas, Anita, et al.
(author)
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Erythropoietin Receptor Expression Is a Potential Prognostic Factor in Human Lung Adenocarcinoma
- 2013
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Journal article (peer-reviewed)abstract
- Recombinant human erythropoietins (rHuEPOs) are used to treat cancer-related anemia. Recent preclinical studies and clinical trials, however, have raised concerns about the potential tumor-promoting effects of these drugs. Because the clinical significance of erythropoietin receptor (EPOR) signaling in human non-small cell lung cancer (NSCLC) also remains controversial, our aim was to study whether EPO treatment modifies tumor growth and if EPOR expression has an impact on the clinical behavior of this malignancy. A total of 43 patients with stage III-IV adenocarcinoma (ADC) and complete clinicopathological data were included. EPOR expression in human ADC samples and cell lines was measured by quantitative real-time polymerase chain reaction. Effects of exogenous rHuEPO alpha were studied on human lung ADC cell lines in vitro. In vivo growth of human ADC xenografts treated with rHuEPO alpha with or without chemotherapy was also assessed. In vivo tumor and endothelial cell (EC) proliferation was determined by 5-bromo-2'-deoxy-uridine (BrdU) incorporation and immunofluorescent labeling. Although EPOR mRNA was expressed in all of the three investigated ADC cell lines, rHuEPO alpha treatment (either alone or in combination with gemcitabine) did not alter ADC cell proliferation in vitro. However, rHuEPO alpha significantly decreased tumor cell proliferation and growth of human H1975 lung ADC xenografts. At the same time, rHuEPO alpha treatment of H1975 tumors resulted in accelerated tumor endothelial cell proliferation. Moreover, in patients with advanced stage lung ADC, high intratumoral EPOR mRNA levels were associated with significantly increased overall survival. This study reveals high EPOR level as a potential novel positive prognostic marker in human lung ADC.
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| 3. |
- Torok, Szilvia, et al.
(author)
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Limited tumor tissue drug penetration contributes to primary resistance against angiogenesis inhibitors
- 2017
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In: Theranostics. - : Ivyspring International Publisher. - 1838-7640. ; 7:2, s. 400-412
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Journal article (peer-reviewed)abstract
- Resistance mechanisms against antiangiogenic drugs are unclear. Here, we correlated the antitumor and antivascular properties of five different antiangiogenic receptor tyrosine kinase inhibitors (RTKIs) (motesanib, pazopanib, sorafenib, sunitinib, vatalanib) with their intratumoral distribution data obtained by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). In the first mouse model, only sunitinib exhibited broad-spectrum antivascular and antitumor activities by simultaneously suppressing vascular endothelial growth factor receptor-2 (VEGFR2) and desmin expression, and by increasing intratumoral hypoxia and inhibiting both tumor growth and vascularisation significantly. Importantly, the highest and most homogeneous intratumoral drug concentrations have been found in sunitinib-treated animals. In another animal model, where - in contrast to the first model - vatalanib was detectable at homogeneously high intratumoral concentrations, the drug significantly reduced tumor growth and angiogenesis. In conclusion, the tumor tissue penetration and thus the antiangiogenic and antitumor potential of antiangiogenic RTKIs vary among the tumor models and our study demonstrates the potential of MALDI-MSI to predict the efficacy of unlabelled small molecule antiangiogenic drugs in malignant tissue. Our approach is thus a major technical and preclinical advance demonstrating that primary resistance to angiogenesis inhibitors involves limited tumor tissue drug penetration. We also conclude that MALDI-MSI may significantly contribute to the improvement of antivascular cancer therapies.
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| 4. |
- Török, Szilvia, et al.
(author)
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Localization of sunitinib, its metabolites and its target receptors in tumor bearing mice: a MALDI mass spectrometry imaging study
- 2015
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In: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 172:4, s. 1148-1163
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Journal article (peer-reviewed)abstract
- A functional blood vessel network is essential for maintaining the necessary oxygen and nutrient levels in solid tumors. Thus, the inhibition of blood vessel growth by different antiangiogenic agents has become one of the most important topics in cancer research over the past few decades. The in vitro studies of these drugs are promising, but both the in vivo and the clinical experiences are controversial. Therefore, investigating the pharmacokinetic parameters of these compounds is a pivotal issue in drug development. In this study, the detection and the adsorption, distribution, metabolism, elimination (ADME) of the antiangiogenic receptor tyrosine kinase inhibitor (RTKI) sunitinib is analyzed in a subcutaneous syngeneic murine tumor model of colorectal cancer. The parent molecule of sunitinib was detected at m/z 399.218 with fragment ions at m/z 326.1 and 283.1 with matrix assisted laser desorption ionization (MALDI) technique. Metabolites of the drug were measured in blood samples and main metabolites were found in tumor, liver and kidney tissues at m/z 371.188, 397.203 and 415.214. Tissue distribution of the drug and its metabolites showed an overlapping pattern by MALDI imaging. The present study supports the role of the MALDI technique in the ADME characterization of drug candidates in preclinical drug development.
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