title: Shikonin Induces Apoptotic Cell Death via Regulation of p53 and Nrf2 in AGS Human Stomach Carcinoma Cells.
abstract: Shikonin, which derives from Lithospermum erythrorhizon, has been traditionally used against a variety of diseases, including cancer, in Eastern Asia. Here we determined that shikonin inhibits proliferation of gastric cancer cells by inducing apoptosis. Shikonin's biological activity was validated by observing cell viability, caspase 3 activity, reactive oxygen species (ROS) generation, and apoptotic marker expressions in AGS stomach cancer cells. The concentration range of shikonin was 35-250 nM with the incubation time of 6 h. Protein levels of Nrf2 and p53 were evaluated by western blotting and confirmed by real-time PCR. Our results revealed that shikonin induced the generation of ROS as well as caspase 3-dependent apoptosis. c-Jun-N-terminal kinases (JNK) activity was significantly elevated in shikonin-treated cells, thereby linking JNK to apoptosis. Furthermore, our results revealed that shikonin induced p53 expression but repressed Nrf2 expression. Moreover, our results suggested that there may be a co-regulation between p53 and Nrf2, in which transfection with siNrf2 induced the p53 expression. We demonstrated for the first time that shikonin activated cell apoptosis in AGS cells via caspase 3- and JNK-dependent pathways, as well as through the p53-Nrf2 mediated signal pathway. Our study validates in partly the contribution of shikonin as a new therapeutic approaches/ agent for cancer chemotherapy.
authors.affiliation: Laboratory of Molecular Oncology, Cheil General Hospital and Women's Healthcare Center, Dankook University College of Medicine, Seoul 04619, Republic of Korea.
authors.forename: Hyeonseok
authors.initials: H
authors.lastname: Ko
authors.affiliation: College of Life Sciences & Biotechnology, College of Medicine, Korea University, Seoul 02841, Republic of Korea.
authors.forename: Sun-Joong
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Microbiology, College of Medicine, Korea University, Seoul 02841, Republic of Korea.
authors.forename: So Hee
authors.initials: SH
authors.lastname: Shim
authors.affiliation: College of Life Sciences & Biotechnology, College of Medicine, Korea University, Seoul 02841, Republic of Korea.
authors.forename: HyoIhl
authors.initials: H
authors.lastname: Chang
authors.affiliation: Asan Institute for Life Sciences, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Republic of Korea.
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Ha
keywords: Apoptosis; JNK; Nrf2; ROS; Shikonin; p53