Chloroquine is a zinc ionophore.
Level 5 - mechanism / opinion, no new human data
In vitro bench research using human cancer cell lines
PubMed 25271834 · doi:10.1371/journal.pone.0109180
What was done
Researchers investigated the interaction between zinc ions and chloroquine in a human ovarian cancer cell line (A2780). Zinc uptake was measured using a fluorescent zinc probe across varying concentrations of chloroquine. Specificity was tested using the metal-binding chelator TPEN and competing copper or iron ions. Fluorescent microscopy was used to assess intracellular zinc localization, and the effects of combined chloroquine and zinc on cell cytotoxicity and apoptosis were evaluated.
What was found
The abstract reports directional outcomes without specific numerical values. Chloroquine increased zinc uptake in A2780 cells in a concentration-dependent manner. This uptake was attenuated by TPEN, whereas copper or iron ions had no effect. Free zinc ions concentrated primarily in lysosomes after chloroquine addition. Combining chloroquine with zinc enhanced cytotoxicity and induced apoptosis in A2780 cells.
Why it matters
This study identifies chloroquine as a zinc ionophore, providing a plausible mechanism for how it alters lysosomal function and enhances cytotoxicity in cancer cells.
Limits
The findings are limited entirely to in vitro experiments in a single cell line (A2780); in vivo models and human clinical validation were not conducted. The abstract does not report exact concentrations, quantitative effect sizes, or statistical metrics.
Cited by
- supports Chloroquine diphosphate acts as a zinc ionophore and increases intracellular zinc levels in cell culture.