Alkylphosphocholines: a new approach to inhibit cell proliferation in proliferative vitreoretinopathy

Comparative transcriptomic analysis reveals adriamycin-induced apoptosis via p53 signaling pathway in retinal pigment epithelial cells

OBJECTIVE

This paper applied a transcriptomic approach to investigate the mechanisms of adriamycin (ADR) in treating proliferative vitreoretinopathy (PVR) using ARPE-19 cells.

METHODS

The growth inhibitory effects of ADR on ARPE-19 cells were assessed by sulforhodamine B (SRB) assay and propidium iodide (PI) staining using flow cytometry. The differentially expressed genes between ADR-treated ARPE-19 cells and normal ARPE-19 cells and the signaling pathways involved were investigated by microarray analysis. Mitochondrial function was detected by JC-1 staining using flow cytometry and the Bcl-2/Bax protein family. The phosphorylated histone H2AX (γ-H2AX), phosphorylated checkpoint kinase 1 (p-CHK1), and phosphorylated checkpoint kinase 2 (p-CHK2) were assessed to detect DNA damage and repair.

RESULTS

ADR could significantly inhibit ARPE-19 cell proliferation and induce caspase-dependent apoptosis in vitro. In total, 4479 differentially expressed genes were found, and gene ontology items and the p53 signaling pathway were enriched. A protein-protein interaction analysis indicated that the TP53 protein molecules regulated by ADR were related to DNA damage and oxidative stress. ADR reduced mitochondrial membrane potential and the Bcl-2/Bax ratio. p53-knockdown restored the activation of c-caspase-3 activity induced by ADR by regulating Bax expression, and it inhibited ADR-induced ARPE-19 cell apoptosis. Finally, the levels of the γ-H2AX, p-CHK1, and p-CHK2 proteins were up-regulated after ADR exposure.

CONCLUSIONS

The mechanism of ARPE-19 cell death induced by ADR may be caspase-dependent apoptosis, and it may be regulated by the p53-dependent mitochondrial dysfunction, activating the p53 signaling pathway through DNA damage.

Pharmacotherapies for Retinal Detachment

Retinal detachment is an important cause of visual loss. Currently, surgical techniques, including vitrectomy, scleral buckle, and pneumatic retinopexy, are the only means to repair retinal detachment and restore vision. However, surgical failure rates may be as high as 20%, and visual outcomes continue to vary secondary to multiple processes, including postoperative cystoid macular edema, epiretinal membrane formation, macular folds, and, ultimately, photoreceptor death. Therefore, pharmacotherapies are being sought to aid the success rates of modern surgical techniques and reduce or slow the degeneration of photoreceptors during retinal detachment. This review discusses potential therapeutic avenues that aid in retinal reattachment, reduce the rate of retinal redetachment by limiting proliferative vitreoretinopathy, and protect against photoreceptor cell death.

Attenuation of human lens epithelial cell spreading, migration and contraction via downregulation of the PI3K/Akt pathway

BACKGROUND

Posterior capsule opacification (PCO) represents a major challenge in the postoperative management of cataract patients. Spreading, migration and contraction of residual human lens epithelial cells play a pivotal role in the pathogenesis of PCO. Therefore, we analyzed the effect of the alkylphosphocholine (APC) erufosine on these cellular features as well as on PI3K/Akt, a crucial pathway in PCO pathogenesis.

METHODS

Human lens epithelial cells were cultured under standard cell culture conditions. Cell spreading was analyzed on fibronectin-coated wells and chemokinetic migration was assessed by time-lapse microscopy. For evaluation of cell-mediated collagen matrix contraction, the cells were seeded into collagen gels and incubated with an APC in different non-toxic concentrations before the surface area was measured on day 6. The activity of PI3K/Akt was assessed by an ELISA kit after incubation of the cells with different APC concentrations.

RESULTS

Human lens epithelial cell spreading and migration were attenuated by APCs as follows: 7 % spreading, 48 % migration (0.1 μM APC), and 32 % spreading, 68 % migration (1.0 μM APC). APC concentrations of 0.1 μM reduced collagen gel diameter by 5 %, and 1.0 μM by less than 1 %, compared to untreated, cell-populated gels that resulted in a cell diameter contraction of 36 %. PI3K was downregulated in a concentration-dependent manner.

CONCLUSIONS

The crucial cellular features of PCO pathogenesis are attenuated by the APC erufosine via downregulation of the PI3K pathway. Thus, erufosine might become a valuable tool for pharmacologic PCO prophylaxis in the future.