Abstract
Erythropoietin (Epo) receptor (EpoR) is expressed in several cancer cell lines, and the functional consequence of this expression is under extensive study. In this study, we used a cervical cancer cell line in which EpoR was first found to be expressed and to correlate with the severity of the disease. We demonstrate that Epo is a chemoattractant for these cancer cells, enhancing their migration under serum-starved conditions. Using a Transwell migration system, we show that Epo enhances cancer cell migration in a dose- and time-dependent manner. The effect of Epo is dependent on the activity of two signaling pathways: the mitogen-activated protein kinase (MAPK) pathway and the RhoA GTPase pathway. We show that Epo activates both pathways in a Janus kinase-dependent manner and that this activation is required for Epo effects on cell migration. Furthermore, we use both pharmacological and genetic inhibitors to demonstrate that the activation of RhoA GTPase is dependent on the activity of the MAPK pathway, providing the first evidence for interaction between these two signaling cascades.
Footnotes
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This work was supported by the Roy J. Carver Charitable Trust as a Research Program of Excellence and the Roland W. Holden Family Program for Experimental Cancer Therapeutics.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.107.129643.
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ABBREVIATIONS: Epo, erythropoietin; Jak, Janus kinase; EpoR, erythropoietin receptor; Erk, extracellular signal-regulated kinase; MAPK, mitogen-activated protein kinase; Stat, signal transducer and activator of transcription; MEK, MAPK kinase; AG490, α-cyano-(3,4-dihydroxy)-N-benzylcinnamide; PD98059, 2′-amino-3′-methoxyflavone; LPA, lysophosphatidic acid; Y-27632, N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide; FR180204, 5-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)-1H-pyrazolo[3,4-c]pyridazin-3-amine; MEM, minimum essential medium; PAGE, polyacrylamide gel electrophoresis; GST, glutathione S-transferase; RBD, Rho binding domain; MTT, 3-(4-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide; IGF, insulin-like growth factor; DN, dominant-negative form of MEK1; ROCK, Rho kinase; GEF, guanine exchange factor; MLCK, myosin light chain kinase.
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↵1 Current affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, CT.
- Received August 2, 2007.
- Accepted December 11, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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