title: Pharmacological implications from the adhesion-induced signaling profiles in cultured human retinal pigment epithelial cells.
abstract: Extracellular matrix (ECM) plays an active and complex role in regulating cellular behaviors, including proliferation and adhesion. This study aimed at delineating the adhesion-induced signaling profiles in cultured human retinal pigment epithelium (RPE) cells and investigating the antiadhesion effect of antiproliferative drugs in this context. RPE R-50 cells grown on various ECM molecules, such as type I and IV collagens, fibronectin, and laminin, were used for adhesion assay and for examining the phosphorylation profiles of signaling mediators including Akt, extracellular signal-regulated kinase (ERK) 1/2, and integrin-linked kinase (ILK) using Western blotting. The cells receiving antiproliferative drug treatment at subtoxic doses were used to evaluate their antiadhesive and suppressive effects on kinase activities. ECM coating enhanced adhesion and spreading of RPE cells significantly. The cellular attachment onto ECM-coated surfaces differentially induced Akt, ERK1/2, and ILK phosphorylation, and concomitantly increased p53 phosphorylation and cyclin D1 expression, but decreased Bcl-2/Bax ratios. Treatment with antiproliferative agents, including 5-fluorouracil, mitomycin C, and daunomycin, at subtoxic doses suppressed the ability of RPE cells to adhere to ECM substratum significantly. This suppression was in part mediated through reduction of integrin β1 and β3 expressions and interfering Akt-ILK signaling activity. Mechanistically, blockade of PI3K/Akt signaling resulted in the suppressed adhesion of RPE cells to ECM. These findings support the hypothesis that, in addition to their antimitogenic effect, antiproliferative agents also exhibit suppressive effect on the adhesiveness of cultured RPE cells. Moreover, inhibitors of the PI3K/Akt signaling mediator can potentially be used as therapeutic agents for proliferative vitreoretinopathy.
authors.affiliation: Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wen-Chuan
authors.initials: WC
authors.lastname: Wu
authors.affiliation: Department of Ophthalmology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yo-Chen
authors.initials: YC
authors.lastname: Chang
authors.affiliation: Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Kwou-Yeung
authors.initials: KY
authors.lastname: Wu
authors.affiliation: Department of Nursing, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Su-Yueh
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ming-Chu
authors.initials: MC
authors.lastname: Hsieh
authors.affiliation: Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Meng-Hsien
authors.initials: MH
authors.lastname: Wu
authors.affiliation: Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Horng-Jiun
authors.initials: HJ
authors.lastname: Wu
authors.affiliation: Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu-Chi University, Hualien, Taiwan.
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Wu
authors.affiliation: Department of Medical Research, E-Da Hospital, Kaohsiung, Taiwan. Electronic address: danyhkao@gmail.com.
authors.forename: Ying-Hsien
authors.initials: YH
authors.lastname: Kao
mesh_terms: D000268:Adhesiveness / Q000187:drug effects; D017209:Apoptosis / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D003630:Daunorubicin / Q000494:pharmacology*; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D016685:Mitomycin / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology*; D015398:Signal Transduction / Q000187:drug effects; D000099200:Scaffold Protein ILK
chemical_list: D003630:Daunorubicin; D048049:Extracellular Signal-Regulated MAP Kinases; D005472:Fluorouracil; D016685:Mitomycin; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000099200:Scaffold Protein ILK
keywords: Akt; Extracellular matrix; Fibronectin; Integrin-linked kinase; Mitogen-activated protein kinases