Induction of apoptosis in Jurkat cells by Mareng-roipad formulation

Abstract

Mareng-roipad formulation is a traditional medicine which is alternatively used for cancer treatment longer than a century. This study intended to evaluate anti-tumor activity of the formulation on human acute leukemic T cells, Jurkat cells, and on normal human peripheral blood mononuclear cells (PBMCs). The water and the ethanol extracts of the formulation were investigated for cytotoxicity, apoptotic induction and mechanisms of apoptotic induction. By propidium iodide (PI) staining assay, both water and ethanol extracts (10-1000 µg/ml) exhibited cytotoxicity in a dose and time-dependent manner with the higher potency of the water than the ethanol extract. The Jurkat cell apoptosis induced by the extracts (10-1000 µg/ml) was examined by annexinV-FITC staining monitored by fluorescence flow cytometer. Both extracts induced apoptosis of Jurkat cells in a dose-dependent manner with IC50 at 15 µg/ml of the water and 150 µg/ml of the ethanol extract. The apoptotic activity of both extract was confirmed by assessing hypodiploid DNA in apoptotic cells after PI staining. These extracts had much less apoptotic activities on PBMCs from healthy subjects. The mechanisms of apoptotic induction of the extracts were also investigated by using a general caspase inhibitor, z-VAD-fmk, and an anti-Fas ligand (FasL) antibody. It was evaluated that the extracts induced Jurkat cell apoptosis mainly by Fas-FasL signaling pathway and in part by caspase activatin. The results in this study indicate that the water and the ethanol extracts of Mareng-roipad formulation can induce human leukemic cell apoptosis mainly by the death receptor pathway. This formulation may have potential to be a traditional medicine for treatment of leukemia.