Coumestrol induces mitochondrial dysfunction by stimulating ROS production and calcium ion influx into mitochondria in human placental choriocarcinoma cells.

Study Question: Does coumestrol inhibit proliferation of human placental choriocarcinoma cells?
Summary Answer: Coumestrol promotes cell death in the choriocarcinoma cells by regulating ERK1/2 MAPK and JNK MAPK signaling pathways and through disruption of Ca2+ and ROS homeostasis.
What Is Known Already: A number of patients who suffer from choriocarcinomas fail to survive due to delayed diagnosis or a recurrent tumor and resistance to traditional chemotherapy using platinum-based agents and methotrexate. To overcome these limitations, it is important to discover novel compounds which have no adverse effects yet can inhibit the expression of a target molecule to develop, as a novel therapeutic for prevention and/or treatment of choriocarcinomas.
Study Design, Size, Duration: Effects of coumestrol on human placental choriocarcinoma cell lines, JAR and JEG3, were assessed in diverse assays in a dose- and time-dependent manner.
Participcants/materials, Setting, Methods: Effects of coumestrol on cell proliferation, apoptosis (annexin V expression, propidium iodide staining, TUNEL and invasion assays), mitochondria-mediated apoptosis, production of reactive oxygen species (ROS), lipid peroxidation, glutathione levels and endoplasmic reticulum (ER) stress proteins in JAR and JEG3 cells were determined. Signal transduction pathways in JAR and JEG3 cells in response to coumestrol were determined by western blot analyses.
Main Results and the Role of Chance: Results of the present study indicated that coumestrol suppressed proliferation and increased apoptosis in JAR and JEG3 cells by inducing pro-apoptotic proteins, Bax and Bak. In addition, coumestrol increased ROS production, as well as lipid peroxidation and glutathione levels in JAR and JEG3 cells. Moreover, coumestrol-induced depolarization of mitochondrial membrane potential (MMP) and increased cytosolic and mitochondrial Ca2+ levels in JAR and JEG3 cells. Consistent with those results, treatment of JAR and JEG3 cells with a Ca2+ chelator and an inhibitor of IP3 receptor decreased coumestrol-induced depolarization of MMP and increased proliferation in JAR and JEG3 cells.
Large Scale Data: N/A.
Limitations, Reasons for Caution: A lack of in vivo animal studies is a major limitation of this research. The effectiveness of coumestrol to induce apoptosis of human placental choriocarcinoma cells requires further investigation.
Wider Implications of the Findings: Our results indicate that coumestrol induces apoptotic effects on placental choriocarcinoma cells by regulating cell signaling and mitochondrial-mediated functions, with a potential to impair progression of the cancer.
Study Funding/competing Interest(s): This research was supported by grants from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (No. HI15C0810 awarded to G.S. and HI17C0929 awarded to W.L.).
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