Glycyrrhizic acid induces apoptosis in WEHI-3 mouse leukemia cells through the caspase- and mitochondria-dependent pathways

Abstract

Abstract. Leukemia, one of the causes of cancer-related death in humans, is an aggressive malignancy via the rapid growth of abnormal white blood cells. The aim of this study was to determine the anti-leukemia effect of glycyrrhizic acid (GA) on a mouse leukemia cell line, WEHI-3. GA, an active compound in Glycyrrhiza glabra, has been proven to induce cytotoxic effects in many cancer cell lines. In the current study, we investigated the effects of GA in mouse leukemia cells in vitro. The results indicated that GA induced morphological changes, G 0 /G 1 phase arrest, apoptosis and DNA damage in WEHI-3 cells as determined by phase contrast microscopy, DAPI-staining, flow cytometry and comet assay. The results from the flow cytometric assay showed that GA increased ROS levels, reduced the mitochondrial membrane potential (ΔΨm) and stimulated caspase-3 activity in WEHI-3 cells. GA regulated the intrinsic and extrinsic apoptosis-associated protein expression which was determined by western blotting. In addition, endoplasmic reticulum (ER) stress responses were observed in GA-treated WEHI-3 cells. GA promoted the trafficking of apoptosis-inducing factor (AIF), cytochrome c and endonuclease G (Endo G) in WEHI-3 cells. Based on this evidence, GA-triggered apoptosis occurs through the death receptor, mitochondria-mediated and ER stress multiple signaling pathways.

Chemopreventive Effects of Licorice and Its Components

“…It also reduced the infiltration of mast cells, attenuated the expression of Ki-67, NF-κB/ p65, COX-2, inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF), while enhancing the expression of p53, connexin-43, caspase-9, and cleaved caspase-3, which suggested the induction of apoptosis [43], also agreeing with other studies [29,42]. GA reportedly induced G0/G1 phase arrest, apoptosis, and DNA damage in WEHI-3 leukemia cells by increasing reactive oxygen species (ROS) levels and caspase-3 activity in these cells [44]. Researchers concluded that GA induced apoptosis through the death receptor, mitochondria-mediated, and endoplasmic reticulum (ER) stress signaling pathways [44].…”

“…GA reportedly induced G0/G1 phase arrest, apoptosis, and DNA damage in WEHI-3 leukemia cells by increasing reactive oxygen species (ROS) levels and caspase-3 activity in these cells [44]. Researchers concluded that GA induced apoptosis through the death receptor, mitochondria-mediated, and endoplasmic reticulum (ER) stress signaling pathways [44].…”

Treatment of Hematological Malignancies with Glycyrrhizic Acid

“…Mechanistically, GA led to reduced NF-ĸβ activity in glioblastoma and in a model of colon carcinogenesis (16,18). Increased caspase activity and oxidative stress were noted in leukemia and colon cancer (16,24). Evidence presented in our study show that GA induces high levels of ROS generation.…”

“…Our findings that GA effectively reduces CML proliferation in vitro and reduces leukemia tumor load in vivo provide additional support for the possible use of GA in the treatment of hematological malignancies. While the mechanism of GA activity against tumors is still under investigation, previous work showed that exposure to GA led to the induction of apoptosis in a number of cancer cell types (7,15,18,24). Mechanistically, GA led to reduced NF-ĸβ activity in glioblastoma and in a model of colon carcinogenesis (16,18).…”

“…However, there are a limited number of reports of GA being effective against leukemias. Chueh et al reported that exposure of the mouse leukemia cell line WEHI-3 led to cell cycle arrest and the induction of apoptosis (24). In addition, He et al reported that GA treatment led to reduced proliferation of the human leukemia cell line TF-1 and that GA treatment inhibited TF-1 growth in vivo (7).…”