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J.D. Paauw, P.C. Kothary, M.A. Del Monte; Role of c-MYC Protein in Platelet-Derived Growth Factor (PDGF)-Induced Mitogenesis of Human Retinal Pigment Epithelial (hRPE) Cells . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2945.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: PDGF is a growth factor for human retinal pigment epithelial (hRPE) cells and has been implicated in pathological epiretinal membrane formation. We investigated the roles of the intracellular signaling molecule Stat3 and protooncogene c-Myc in PDGF-induced hRPE cell proliferation. Methods: hRPE cultures were established from three human eyes obtained from the Michigan Eye Bank. Proliferation of hRPE cells in the presence of increasing concentrations of PDGF (1-100 pg/ml), and in the presence and absence of AG490, a Jak/STAT signaling inhibitor, and Genistein, a phosphotyrosine kinase pathway inhibitor, was measured by direct counting of trypan blue excluding cells. c-Myc protein synthesis was measured by immunoprecipitating 14C-Methionine-labeled c-Myc in the presence of increasing concentrations of PDGF (1-100 pg/ml), and in the presence and absence of AG490 and genistein. Data were analyzed by Student 't' test. p<0.05 was considered to be significantly different. Results: PDGF stimulated hRPE proliferation in a dose-dependent manner. Genistein (0.025 mM) inhibited PDGF (100 pg/ml) stimulated hRPE proliferation (6.5 ±4.1 vs. 21.3 ±7.2, cell number x105± SEM, p=0.0003, n=5). AG490 (0.025mM) also inhibited PDGF (100 pg/ml) stimulated hRPE cell number (1.5 ±1.1 vs. 21.3 ±7.2, cell number x 105± SEM, p=0.0006, n=5). PDGF stimulated c-Myc synthesis in a dose dependent manner. Genistein (0.025 mM) inhibited PDGF (100 pg/ml) stimulated c-Myc synthesis (393.3 ±89.8 vs. 1082.8± 246.1, CPM±SEM, p=0.013, n=6). AG490 (0.025 mM) inhibited PDGF (100 pg/ml) stimulated c-Myc synthesis (279.7 ±114.3 vs. 1082.8± 246.1, CPM±SEM, p=0.019, n=6). Conclusions: PDGF stimulates hRPE cell proliferation through a phosphorylation cascade involving STAT activation and c-Myc synthesis. AG490 or genistein may be useful in preventing or treating proliferative eye diseases.
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