Intracellular zinc status influences cisplatin-induced endothelial permeability through modulation of PKCα, NF-κB and ICAM-1 expression

Platinum-based chemotherapeutic regimen induces vascular dysfunction. Action of cisplatin on endothelial cells is mediated by protein kinase C (PKC-α), which further activates nuclear factor-κB (NF-κB) and induces canonical transient receptor potential channel (TRPC1) and intercellular adhesion molecule (ICAM-1) expression. Increased ICAM-1 contributes to hyperadhesion of monocytes and endothelial dysfunction. PKC-α is also involved in phosphorylation of TRPC1, resulting in store-operated calcium entry (SOCE) and further activation of NF-κB. Although the role of altered intracellular zinc status is not known in cisplatin-induced vascular dysfunction, because of the ability of zinc to modulate PKC-α, NF-κB activity, we hypothesized that zinc can ameliorate the extent of endothelial dysfunction induced by cisplatin. Human umbilical vein endothelial cells treated with cisplatin (8.0 μg/ml) showed lowered intracellular free zinc, concomitant with enhanced activation of PKC-α, NF-κΒ activation, TRPC1, SOCE and ICAM-1 levels. Zinc deficiency per se induced using membrane permeable chelator (TPEN) mimicked the cisplatin-induced PKC-α, NF-κB activation and ICAM-1 expression, but also activated Activator Protein-1 (AP-1). Zinc supplementation (2.0-10.0 μM) to the endothelial cells during cisplatin treatment or TPEN-induced zinc deficiency suppressed PKC-α, NF-κB, TRPC1, SOCE activation and lowered the ICAM-1 expression. Zinc supplementation thereby effectively decreased the cisplatin-induced endothelial permeability and adherence of the activated endothelial cells to U937 monocytes.