Apoptotic and antiproliferative effects of Urtica dioica L. extract on K562 chronic myeloid leukemia cell line.

Urtica dioica L. (stinging nettle) is an herb commonly used as a medical supplement for its anticarcinogenic, antiinflammatory, analgesic, antifungal, and antioxidant effects. In this study, we analyzed phytochemical composition of Urtica dioica ethanol extract and investigated its apoptotic and antiproliferative effects in K562 cell line, a model cell line for chronic myeloid leukemia (CML). K562 cells exposed to different concentrations of U. dioica extract (0, 25, 50, 75 and 100 μg/mL) were tested for cell proliferation and apoptosis using appropriate methods and different phases of the cell cycle were analyzed using flow cytometry. Phenolic content of the plant was analyzed by LC-MS/MS. We showed that U. dioica ethanol extract has four phenolic compounds: caffeic acid, chlorogenic acid (major compound), malic acid and rutin. Urtica dioica significantly repressed proliferation of K562 cells compared to control mononuclear cells (PBMCs) isolated from the peripheral blood of healthy donors. An increase in Bax/Bcl-2 and PARP cleavage ratio, decrease in mitochondrial membrane potential indicated that the extract inhibited cell proliferation through an apoptosis-mediated process. Furthermore, cell cycle arrest at G0/G1 phase increased in a concentration dependent manner. Our results explicitly demonstrate that ethanol extract of Urtica dioica leads to a decrease in cell viability and proliferation, initiates apoptosis, and induces G0/G1 cell cycle accumulation in this cell line. This is the first study to have demonstrated the antiproliferative and apoptotic effects of Urtica dioica on chronic myeloid leukemia (CML) cell lines K562 in vitro. [ABSTRACT FROM AUTHOR]