Lanthanum chloride suppresses hydrogen peroxide-enhanced calcification in rat calcifying vascular cells

Lanthanum chloride (LaCl(3)) has been shown to retard the progression of established atherosclerotic lesions in animal models, and used as a calcium channel blocker in various cellular experiments. In this study, we assessed the role of lanthanum chloride (LaCl(3)) in H(2)O(2)-enhanced calcification in rat calcifying vascular cells (CVCs) and examined the involvement of MAPK signaling pathways. H(2)O(2) induced growth inhibition of CVCs, as well as increases in intracellular levels of calcium and reactive oxygen species, ALP activity, apoptosis and calcium deposition. These effects of H(2)O(2) were suppressed by pretreatment of the cells with 1 muM of LaCl(3) for 2 h. In addition, H(2)O(2) activated the phosphorylation of ERK1/2, JNK and p38 MAPK, but only the last two were associated with the ALP activity. Our findings demonstrate that H(2)O(2)-enhanced osteoblastic differentiation and apoptosis are responsible for the increased calcification in rat CVCs, and LaCl(3) can counteract these effects by suppressing the activation of JNK (JNK2, but not JNK1) and p38 MAPK signaling pathway.