A Cancer-Selective Zinc Ionophore Inspired by the Natural Product Naamidine A

We present data demonstrating the natural product mimic, zinaamidole A (ZNA), is a modulator of metal ion homeostasis causing cancer-selective cell death by specifically inducing cellular Zn2+-uptake in transformed cells. ZNA’s cancer selectivity was evaluated using metastatic, patient-derived breast cancer cells, established human breast cancer cell lines, and three-dimensional organoid models derived from normal and transformed mouse mammary glands. Structural analysis of ZNA demonstrated that the compound interacts with zinc through the N 2-acyl-2-aminoimidazole core. Combination treatment with ZnSO4 strongly potentiated ZNA’s cancer-specific cell death mechanism, an effect that was not observed with other transition metals. We show that Zn2+-dyshomeostasis induced by ZNA is unique and markedly more selective than other known Zn2+-interacting compounds such as clioquinol. The in vivo bioactivity of ZNA was also assessed and revealed that tumor-bearing mice treated with ZNA had improved survival outcomes. Collectively, these data demonstrate that the N 2-acyl-2-aminoimidazole core of ZNA represents a powerful chemotype to induce cell death in cancer cells concurrently with a disruption in zinc homeostasis.