Development of Electrostatically Stabilized siRNA—Peptide Complexes for Anti-Angiogenic Treatment of Endometriosis

Background: Endometriosis (EM) is a benign gynecological disorder characterized by the hyperproliferation of endometrial cells outside the uterus. This abnormal proliferation followed by neoangiogenesis leads to the formation of EM lesions, which often require surgical removal. Contemporary pharmacological treatment of EM involves hormonal therapies, which are frequently accompanied by adverse effects and a high rate of symptom recurrence following cessation of treatment. Consequently, the development of innovative pharmaceuticals is crucial for the effective management of EM. Small interfering RNA (siRNA) therapeutics are evolving from a niche modality into a major pharmaceutical platform applicable for the therapy of inherited and multifactorial diseases. However, a major obstacle hindering broader clinical use is the challenge of delivering siRNA to tissues beyond the liver. Peptide-based nanoparticles mediating siRNA delivery hold potential to overcome this limitation through receptor targeting and by shielding excessive positive charges. Methods: In the current study, we developed ternary polyplexes composed of anti-VEGFA siRNA, a cationic arginine-rich polymer, and an anionic glutamate-rich polymer modified with a cyclic RGD (cRGD) moiety for αVβ3-integrin binding. The polyplexes were characterized physicochemically, and their toxicity and GFP marker gene silencing properties were studied in vitro. Anti-angiogenic effects were evaluated in vivo using a surgically induced EM model in female Wistar rats. Results: A significant reduction in the volume of modeled EM lesions, along with decreased VEGFA gene expression and apparent reduction in endothelial marker CD34 immunostaining in representative sections, was observed following intralesional administration of anti-VEGFA siRNA-loaded peptide-based nanoparticles decorated with the cRGD ligand, compared to control ligand-free nanoparticles. Conclusions: The results provide evidence that electrostatically stabilized siRNA-peptide nanoparticles can exert anti-angiogenic effects in EM lesions following intralesional administration, warranting further investigation of their targeting properties, safety, and therapeutic potential.