Antiviral, antiangiogenic and antiinflammatory activities of stigmastane derivatives, a novel class of broad spectrum antiviral effectors

ALCHÉ, L.E.

Mar del Plata - Pcia. de Buenos Aires

Congreso; LXI Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clínica (SAIC)

Many viral infections are associated with the development of immunopathologies for which no vaccines and/or antiviral drugs are available yet. The treatment of these diseases usually includes corticosteroids which can result in reactivation of the virus, as it occurs in the case of Herpes simplex virus (HSV) infections. Particularly, HSV type 1 (HSV-1) triggers an ocular disease in humans named herpetic stromal keratitis (HSK) that can lead to vision impairment and blindness. HSK develops as a consequence of the arrival of inflammatory cells to the cornea in response to viral infection through the appearance of new vessels. While inflammatory cells are responsible for the elimination of HSV-1 from the eye, they cause an uncontrolled inflammatory response that culminates in the development of HSK.We have demonstrated that a polyfunctionalized stigmastane derivative (22S,23S)-22,23-dihydroxystigmast-4-en-3-one (1) inhibits HSV-1 replication in both human corneal and conjunctival cell lines with no cytotoxicity, and reduces the signs of HSK in a mouse experimental model. On the other hand, compound 1 decreases IL-6 production in stimulated macrophages, a cytokine which is crucial for the development of neovascularization along HSK progression. Besides, RNA microarrays have revealed various overexpressed and repressed genes in compound 1 treated HSV-1 infected cells and activated macrophages, many of which are associated with innate responses and inflammatory processes. Thus, compound 1, and others belonging to the same family of molecules, proved to combine antiviral and anti-inflammatory properties in the same chemical structure. Since angiogenesis plays a critical role in initiating and promoting several diseases, such as HSK and cancer, we have studied the effect of compound 1 on capillary tube-like structures and on cell migration of human umbilical vein endothelial cells (HUVEC), as well as on VEGF expression, given that VEGF is a primary angiogenic factor operating in HSV-infected cornea and is considered a target to treat corneal neovascularization. Compound 1 significantly restrains the ability of HUVECs to form capillary tubes when added together with cells, although it does not cause any cytotoxic effect on the tubes already established, and it efficiently suppresses IL-6-stimulated HUVEC migration, in a concentration-dependent manner. In addition, compound 1 diminishes VEGF expression when induced by two different stimuli in macrophages.In vivo, a significant decrease in the incidence and severity of corneal neovascularization during the development of HSK has been achieved by compound 1, which explains the improvement of the signs of disease in the murine experimental model.Additional benefits of compound 1 have been observed, since it exerts an antiangiogenic effect on the neovascular response induced by LMM3 cells in mice, by reducing the number of neovessels in a murine model of breast cancer.This novel effect of compound 1 is not shared with other compounds belonging to the same family of synthetic analogs with antiviral and anti-inflammatory properties, which lead us to conclude that the antiangiogenic effect of compound 1 is not a consequence of its anti-inflammatory activity.In summary, the synthetic stigmastane designed as compound 1 would be a promising compound not only to cure an immunopathology of viral origin like HSK, but also to improve other diseases where angiogenesis is the major pathogenic factor, as in the case of solid tumors.