Cytotoxicity and genotoxicity of a monazite component: lanthanum effects on the viability and induction of breaks in the DNA of human lymphocytes

The Monazite is a mineral extracted from open mines. It is constituted by lanthanum element aggregated with cerium, yttrium and thorium [(Ce, La, Y, Th)PO4]. Lanthanum (La) is a rare-earth metal with applications in agriculture, industry and medicine. Since lanthanides and their compounds show a broad spectrum of applications there is an increased risk of incorporation in human. Inhalation of aerosols containing La is the main route of incorporation in workers exposed to several chemical forms of La. Herein, we examined the effect of lanthanum nitrate - La(NO3)3 in human lymphocytes. JURKAT cells and human peripheral lymphocytes (HPL) were used to evaluate the effect of La(NO3)3 on viability (apoptosis or necrosis) and DNA strand breaks induction or/and alkali-labile sites (ALS). We demonstrate that La has a cytotoxic and genotoxic effect on both cell lines. The results indicate that necrosis is the pathway by which La(NO3)3 induces cytotoxicity. The vitamin E is able to diminish DNA strand breaks induced by La(NO3)3 suggesting that reactive oxygen species (ROS) may be involved in the genotoxic process. (author)