Paracrine Stimulation of P2X7 Receptor by ATP Activates a Proliferative Pathway in Ovarian Carcinoma Cells
ABSTRACT P2X7 is a purinergic receptor‐channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non‐cancerous and cancer patients were analy...
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Published in | Journal of cellular biochemistry Vol. 115; no. 11; pp. 1955 - 1966 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Blackwell Publishing Ltd
01.11.2014
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | ABSTRACT
P2X7 is a purinergic receptor‐channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non‐cancerous and cancer patients were analyzed by immunohistochemistry. Ovarian surface epithelium in healthy tissue expressed P2X7 at a high level that was maintained throughout the cancer. The cell lines SKOV‐3 and CAOV‐3 were used to investigate P2X7 functions in OCA. In SKOV‐3 cells, selective stimulation of P2X7 by 2′(3′)‐O‐(4‐benzoylbenzoyl) adenosine‐5′‐triphosphate (BzATP) induced a dose‐dependent increase of intracellular Ca2+ concentration ([Ca2+]i) but not cell death. Instead, BzATP increased the levels of phosphorylated ERK and AKT (pERK and pAKT), with an EC50 of 44 ± 2 and 1.27 ± 0.5 μM, respectively; 10 μM BzATP evoked a maximum effect within 15 min that lasted for 120 min. Interestingly, basal levels of pERK and pAKT were decreased in the presence of apyrase in the medium, strongly suggesting an endogenous, ATP‐mediated phenomenon. Accordingly: (i) mechanically stimulated cells generated a [Ca2+]i increase that was abolished by apyrase; (ii) apyrase induced a decrease in culture viability, as measured by the MTS assay for mitochondrial activity; and (iii) incubation with 10 μM AZ10606120, a specific P2X7 antagonist and transfection with the dominant negative P2X7 mutant E496A, both reduced cell viability to 70.1 ± 8.9% and to 76.5 ± 5%, respectively, of control cultures. These observations suggested that P2X7 activity was auto‐induced through ATP efflux; this increased pERK and pAKT levels that generated a positive feedback on cell viability. J. Cell. Biochem. 115: 1955–1966, 2014. © 2014 Wiley Periodicals, Inc. |
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Bibliography: | Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica UNAM, México - No. IN205114; No. IA200112; No. IN205312 istex:065409031059F1B5D90C5DDB5A63A63822550DB0 ark:/67375/WNG-85T057M8-Z Consejo Nacional de Ciencia y Tecnología, México - No. 166725 ArticleID:JCB24867 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0730-2312 1097-4644 |
DOI: | 10.1002/jcb.24867 |