A novel anti-RUNX1 therapy modulates retinal angiogenesis: Drug delivery and in vivo efficacy

Abstract

Purpose : The discovery of the role of RUNX1 in retinal angiogenesis drove the study of novel therapeutic approaches. We designed a nanoemulsion(eNanoRo24) loaded with a small molecule inhibitor of RUNX1(Ro24-7429) that reduced the proliferation and migration of endothelial cells in vitro. This work explores the systemic administration of eNanoRo24 as an anti-angiogenic therapy by RUNX1 inhibition.

Methods : eNanoRo24 drop size was characterized by dynamic light scattering(DLS), in vitro drug release was studied with dialysis, and Ro24-7429 levels were measured by high-performance liquid chromatography(HPLC). Electron microscopy(EM), gene and protein expression evaluated the internalization of eNanoRo24 in human microvascular endothelial cells(HMRECs). Finally, in vivo efficacy was determined by serial intraperitoneal injections of eNanoRo24 in mice. We used both laser-induced choroidal neovascularization(Laser CNV) and a VEGF overexpression model(Kimba 029). Retinal vasculature was studied by fundus fluorescence angiography(FFA) and HPLC in post-mortem tissue measured drug distribution.

Results : eNanoRo24 had a drop size smaller than 100 nm and sustained drug release over 100 hours(Fig. 1A). It was not toxic for endothelial cells after 72 hours. Moreover, endothelial cells internalized eNanoRo24. They formed multivesicular bodies inside the cells(Fig. 1B) by a mechanism linked with clathrin-mediated endocytosis(Fig. 1C). Leakage severity was reduced by the systemic administration of eNanoRo24, decreasing the pathology severity relative to controls(Fig. 1D,E) in both Laser CNV and Kimba 029. eNanoRo24 efficacy is dose-dependent, and the systemic administration reached several organs in the mice's body, including effective concentrations in the eye.

Conclusions : eNanoRo24 reached functional concentrations in the eye, inhibiting pathologic retinal neovascularization. eNanoRo24 is a novel therapeutic approach that targets RUNX1 via systemic administration, presenting a therapeutic alternative that can enhance the outcomes of the current treatments.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Fig. 1. Drug delivery and in vivo efficacy of eNanoRo24 A. cumulative sustained release of Ro24-7429, B. Multivesicular body found in HMRECs by EM(scale bar=500 nm). C. co-localization of clathrin(magenta) and lipid bodies(Red) formed by eNanoRo24(scale bar=20 mm) D. FFA of untreated and, E. treated with eNanoRo24 Kimba 029 mice