Inhibition of insulin signaling by oxidized low density lipoprotein. Protective effect of the antioxidant Vitamin E.

Oxidative stress is involved in several pathological conditions, including diabetes. Reactive oxygen species (ROS) have been demonstrated to act as second messengers for several hormones and cytokines, including insulin (INS). The effect of Cu(2+)-oxidized LDL (CuLDL) on INS-induced generation of ROS and on INS signaling was investigated on cultured human fibroblasts.

Impairment of the EGF signaling pathway by the oxidative stress generated with UVA.

Ultraviolet A (UVA) is a component of sunlight reaching the surface of the earth and involved in photodegenerescence and photocarcinogenesis. The effect of UVA was investigated on the EGF-induced activation of the signaling kinase ERK and the transcription factors AP1, NFkappaB, and STAT1. UVA prevented the Epidermal Growth Factor (EGF)-induced stimulation of ERK in a dose-dependent manner within the range of 1.

Oxidized low density lipoprotein induces the cyclin-dependent kinase inhibitor p21(waf1) and the tumor suppressor Rb.

Oxidized low density lipoprotein (OxLDL) is known to be cytotoxic towards different cell types of the arterial wall, leading to progression of an atherosclerotic plaque. We previously reported that OxLDL activates the tumor suppressor p53 in human fibroblasts [Biochem. Biophys.