naphthoquinones and Vitreoretinopathy--Proliferative

BACKGROUND This study aimed to explore the effects of plumbagin (PLB) on epithelial-to-mesenchymal transition in retinal pigment epithelial (RPE) cells and in proliferative vitreoretinopathy (PVR) rabbit models. MATERIAL AND METHODS Rabbit RPE cells were exposed to various concentrations (0, 5, 15, and 25 µM) of PLB. Motility, migration, and invasion of PLB-treated cells were determined in vitro using Transwell chamber assays and scratch wound assays. The contractile ability was evaluated by cell contraction assay. Expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT) markers were assessed by western blotting. Furthermore, PLB was injected in rabbit eyes along with RPE cells after gas compression of the vitreous. The presence of PVR was determined by indirect ophthalmoscopy on days 1, 7, 14, and 21 after injection. Also, optical coherence tomography (OCT), ultrasound images, electroretinograms (ERG), and histopathology were used to assess efficacy and toxicity. RESULTS PLB significantly inhibited the migration and invasion of RPE cells. The agent also markedly reduced cell contractive ability. Furthermore, PLB treatment resulted in the decreased expression of MMP-1, MMP2, α-SMA, and the protection of ZO-1. In addition, the PLB-treated eyes showed lower PVR grades than the untreated eyes in rabbit models. PLB exhibited a wide safety margin, indicating no evidence of causing retinal toxicity. CONCLUSIONS PLB effectively inhibited the EMT of rabbit RPE cells in vitro and in the experimental PVR models. The results open new avenues for the use of PLB in prevention and treatment of PVR.

Topics: Animals; Cells, Cultured; Epithelial Cells; Epithelial-Mesenchymal Transition; Naphthoquinones; Rabbits; Retinal Pigment Epithelium; Vitreoretinopathy, Proliferative

This study aimed to explore the effects of plumbagin (PLB) on ARPE-19 cells and underlying mechanism.. Cultured ARPE-19 cells were treated with various concentrations (0, 5, 15, and 25 μM) of PLB for 24 h or with 15 μM PLB for 12, 24 and 48 h. Then cell viability was evaluated by MTT assay and DAPI staining, while apoptosis and cell cycle progression of ARPE cells were assessed by flow cytometric analysis. Furthermore, the level of main regulatory proteins was examinated by Western boltting and the expression of relative mRNA was tested by Real-Time PCR.. PLB exhibited potent inducing effects on cell cycle arrest at G2/M phase and apoptosis of ARPE cells via the modulation of Bcl-2 family regulators in a concentration- and time-dependent manner. PLB induced inhibition of phosphatidylinositol 3-kinase (PI3K) and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways contributing to the anti-proliferative activities in ARPE cells.. This is the first report to show that PLB could inhibit the proliferation of RPE cells through down-regulation of modulatory signaling pathways. The results open new avenues for the use of PLB in prevention and treatment of proliferative vitreoretinopathy.

Topics: Apoptosis; Cell Cycle Checkpoints; Cell Line; Cell Survival; Drugs, Chinese Herbal; Epithelial Cells; Humans; Naphthoquinones; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Plumbaginaceae; Proto-Oncogene Proteins c-akt; Retinal Pigment Epithelium; Signal Transduction; TOR Serine-Threonine Kinases; Vitreoretinopathy, Proliferative

The aim of the study was to determine whether the topoisomerase I inhibitors, camptothecin and beta-lapachone, are suitable agents for the adjuvant pharmacotherapy of proliferative vitreoretinopathy (PVR). The effects of the drugs on cultured human retinal pigment epithelial (RPE) cells were examined using growth assays, cytotoxicity assays, single cell agarose gel electrophoresis, in situ DNA end labeling and immunoblot analysis for apoptosis-regulatory proteins. Both agents killed RPE cells in a concentration-and time-dependent manner. Cell death was apoptotic as assessed by single cell agarose gel electrophoresis and in situ DNA end labeling. Camptothecin, but not beta-lapachone, induced accumulation of p53 and the major growth arrest-associated p53 response protein, p21. Both drugs enhanced expression of the proapoptotic BAX protein. Camptothecin, but not beta-lapachone, synergistically enhanced RPE cell apoptosis induced by the cytotoxic cytokine, CD95 ligand (CD95L). This effect was linked to camptothecin-induced inhibition of RNA synthesis. Atypical topoisomerase I inhibitors may be promising agents for the adjuvant pharmacotherapy of PVR. Experimental studies to assess possible ocular toxicity upon local administration and to confirm its therapeutic efficacy in an animal model of PVR are required.

Topics: Apoptosis; Camptothecin; Cell Culture Techniques; Cell Survival; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Inhibitors; Fas Ligand Protein; fas Receptor; Humans; Membrane Glycoproteins; Naphthoquinones; Pigment Epithelium of Eye; Topoisomerase I Inhibitors; Vitreoretinopathy, Proliferative