Aumento da atividade antioxidante da HDL independentemente da concentração plasmática de HDL-colesterol no câncer de mama triplo-negativo

Abstract

The association between high-density lipoprotein (HDLc) cholesterol concentration and breast cancer is controversial. We evaluated the antioxidant activity of HDL in triple-negative breast cancer compared to controls. We included 27 women with a recent diagnosis of triple-negative breast cancer, naïve to treatment, and 27 healthy women (control group), matched for age and body mass index. HDL and low-density lipoprotein (LDL) were isolated from plasma by ultracentrifugation. The profile of lipids in plasma and HDL was determined by enzymatic methods, and apolipoprotein A-I (apo A-I) and apoB by immunoturbidimetry. The lag time phase and the maximum ratio of conjugated dienes formation in LDL incubated, in vitro, with copper sulfate and HDL from both groups were determined. The control group was similar to breast cancer regarding plasma lipid concentrations and ratios and HDL particle composition. The ability of HDL to delay LDL oxidation was 22% greater in the breast cancer group and was positively correlated with the apoA-I content of HDL, being greater in advanced stages of breast cancer (stages III and IV). The maximum rate of conjugated dienes formation was similar between groups and clinical stages of the disease. The results highlight the role of HDL as an antioxidant defense, regardless of HDLc concentration, helping to limit oxidative stress in advanced stages of triple-negative breast tumors.