Glucosamine inhibits epidermal growth factor-induced proliferation and cell-cycle progression in retinal pigment epithelial cells

[摘要] Purpose: To investigate the effects andmechanisms of glucosamine (GlcN) on the proliferation of retinalpigment epithelial cells in response to epidermal growth factor (EGF). Methods: Cell proliferation was measuredin the human retinal pigment epithelial cell line (ARPE-19) cells withthe 4-[3-(4iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzenedisulfonate (WST-1) assay and cell counting. The results were confirmedin human donor cells with the carboxyfluorescein diacetate succinimidylester cell proliferation assay (CFSE) cell proliferation assay. InARPE-19 cells, cell-cycle progression was determined by flowcytometry; the protein levels of cell cycle regulators and heat shockprotein 90 (Hsp90) were measured by western blotting; the levels andbranching of N-glycans were assessed using the L-Phaseolus vulgarisagglutinin lectin-binding assay; and the modulation of N-glycans on EGFreceptor (EGFR) was examined by western blotting. Results: GlcN inhibited retinal pigmentepithelium (RPE) proliferation in a dose-dependent manner. Duringcell-cycle progression induced by EGF, GlcN caused delays at the G1–Sand G2–M transitions without affecting cell viability. GlcNmodulated the level and branching of N-glycans on EGFR, suppressedphosphorylation of EGFR, and reduced phosphorylation of extracellularsignal-regulated kinases, erine/threonine protein kinase, and thesignal transducer and activator of transcription 3 (STAT3). GlcN hadonly minor effects on the expression of Hsp90, Grp78, and transcriptionfactor CHOP/GADD 153 markers of nonspecific stress in the endoplasmicreticulum. Conclusions: GlcN effectively suppressedproliferation of RPE cells in vitro. This effect appeared to beachieved through modification of N-glycans on EGFR. Further researchinto the role of GlcN as a potential agent for the prevention andtreatment of RPE-mediated ocular proliferative disorders, such asproliferative vitreoretinopathy, and other EGF-dependent proliferativecell-growth disorders, is warranted.

[学科分类] 生物化学/生物物理