Purchase this article with an account.
Temitope Sasore, Breandan N Kennedy; Effective targeting of the PI3K/Akt/mTOR pathway: A promising therapeutic option for the treatment of ocular neovascularization/inflammation/oedema.. Invest. Ophthalmol. Vis. Sci. 2014;55(13):1178.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
There is a clinical need to develop improved pharmacological therapeutics for ocular neovascularization, retinal inflammation and retinal oedema associated with diabetic retinopathy (DR), age-related macular degeneration (AMD) and diabetic macular oedema. In this study, we investigate the in vivo anti-angiogenic efficacy of a panel of PI3K/Akt/mTOR inhibitors, alone and in combination.
Standard and real-time reverse transcription polymerase reaction was used to examine the developmental expression pattern of PI3K/Akt/mTOR target genes in the zebrafish. Tg(fli1:EGFP) transgenic zebrafish were treated with drugs from 2-5 days post fertilisation and inhibitory effects on developmental angiogenesis of intersegmental vessels (ISV) and hyaloid vessels (HV) quantified. Optokinetic response assay assessed effects on visual behaviour. Human retinal pigment epithelial cell number was examined using MTT assay and the localization of the tight junction protein ZO-1 was determined by immunocytochemistry.
RT-PCR and qRT-PCR results demonstrate that PI3K/Akt/mTOR genes are expressed in zebrafish from 6 hours post fertilisation (hpf) to 5 days post fertilisation (dpf). 10 uM of individual drugs had moderate anti-angiogenic activity, but 5 uM combinations of specific PI3K plus mTOR inhibitors ranked as the most efficacious kinase inhibitors in zebrafish. In addition, some combinations exhibited little to no effect on retinal morphology, whilst the effect on visual function is currently being examined. The most active inhibitors do not reduce RPE cell number. In addition, immunofluorescence study is currently being used to examine the effect on cell permeability.
In summary, chemical screens in zebrafish identify a combination of mTOR and PI3K inhibitors that are safe and effective inhibitors of developmental angiogenesis. Therefore, further investigations of the PI3K pathway and drug combinations hold promise for the identification of better therapeutics for ocular neovascularization.
This PDF is available to Subscribers Only