Changwon Yang

Chrysophanol Induces Apoptosis of Choriocarcinoma Through Regulation of ROS and the AKT and ERK1/2 Pathways.

Chrysophanol is an anthraquinone compound, mainly isolated from rhubarb, with anti‐cancer effects on some types of cancer cells. However, effects of chrysophanol on human choriocarcinoma cells are not known. Therefore, the objective of this study was to determine effects of chrysophanol on choriocarcinoma cells (JAR and JEG‐3) and identify signal transduction cascades activated by chrysophanol. Results of present study, showed that chrysophanol decreased cell viability and induced apoptosis of JEG‐3, but not JAR cells, in a dose‐dependent manner. Chrysophanol also increased oxidative stress in JEG‐3 cells by inducing ROS generation followed by mitochondrial dysfunction including depolarization of mitochondrial inner membrane potential. Western blot analysis revealed that ERK1/2, P90RSK, AKT, and P70S6K were increased significantly in JEG‐3 cells by chrysophanol. Next, we investigated chrysophanol‐mediated effects on proliferation of JEG‐3 cells using pharmacological inhibitors of PI3K/AKT (LY294002) and ERK1/2 (U0126). Inhibition of AKT and ERK1/2 prevented chrysophanol‐induced stimulation of proliferation of JEG‐3 cells. In addition, the phosphorylation of AKT and ERK1/2 was suppressed by LY294002 and U0126 in JEG‐3 cells treated with chrysophanol, whereas, the AKT protein was activated by pre‐treatment of JEG‐3 cells with U0126. Furthermore, we compared therapeutic effects of chrysophanol with cisplatin and paclitaxel which are conventional salvage regimens for choriocarcinoma. Our results verified that chrysophanol has synergistic effects with traditional therapy to increase apoptosis of JEG‐3 cells. Collectively, these results indicate that chrysophanol is a potential effective chometherapeutic agent for treatment of choriocarcinoma therapy, and minimizing side effects of conventional treatment regimens. J. Cell. Physiol. 232: 331–339, 2017.

Luteolin Inhibits Proliferation and Induces Apoptosis of Human Placental Choriocarcinoma Cells by Blocking the PI3K/AKT Pathway and Regulating Sterol Regulatory Element Binding Protein Activity

ABSTRACT Luteolin is a natural compound known for its anticancer effects on various human cancers by regulating signal transduction cascades. However, the effects of luteolin on human placental choriocarcinoma are not known. Results of the present study revealed that luteolin decreased viability of JAR and JEG-3 cells, which are valuable placental models, in a dose-dependent manner, and it induced apoptosis and loss of mitochondrial membrane potential in JAR and JEG-3 cells. The results also suggested that the PI3K/AKT pathway was inhibited by luteolin treatment of JAR and JEG-3 cells in a dose- and time-dependent manner. Next, we established effects of luteolin in the presence of pharmacological inhibitors of PI3K/AKT, ERK1/2 MAPK, and mTOR on proliferation of JAR and JEG-3 cells. In addition, these inhibitors were used to verify phosphorylation of AKT, GSK3beta, and ERK1/2 and to confirm mechanisms regulated by luteolin in JAR and JEG-3 cells. We also determined levels of SREBP1 and SREBP2 expression to investigate regulatory functions of luteolin in lipid metabolism in JAR and JEG-3 cells. Expression levels of both SREBP1 and SREBP2 mRNAs were significantly reduced, but only SREBP1 protein was influenced by luteolin. We compared viability of JAR and JEG-3 cells in response to luteolin alone or in combination with other chemotherapeutic drugs (etoposide, cisplatin, and paclitaxel) and found that luteolin has synergistic effects with the conventional chemotherapeutic drugs as an anticancer agent. Collectively, these results showed that luteolin plays an important role in the treatment of human choriocarcinoma cells by inhibiting the PI3K/AKT/mTOR/SREBP cascade and expression of lipogenic genes.

Myricetin suppresses invasion and promotes cell death in human placental choriocarcinoma cells through induction of oxidative stress

Myricetin is a bioactive compound found in a variety of vegetables and fruits, and its anti-cancer effects are well known. In this study, we confirmed that myricetin reduced proliferation of two choriocarcinoma cell lines (JAR and JEG-3) and also promoted apoptosis and regulated cell cycle progression in a dose-dependent manner in JAR and JEG-3 cells. In addition, we found that invasive and pro-angiogenic properties of malignant JAR and JEG-3 trophoblast cells were attenuated by myricetin treatment via MAPK and PI3K/AKT signaling pathways. In addition, we found that ROS production, lipid peroxidation, glutathione depletion, and loss of mitochondrial membrane potentials were enhanced in JAR and JEG-3 cells treated with myricetin. Moreover, myricetin augmented cytosolic Ca2+ release from the endoplasmic reticulum associated with modulation of ER stress in JAR and JEG-3 cells. Our results also revealed that myricetin had synergistic antiproliferative effects with current chemotherapeutics, etoposide and cisplatin, on choriocarcinoma cells. Collectively, results of the present study provide strong evidence for the potential of myricetin to be an effective therapeutic for the prevention of human placental choriocarcinomas.

Inhibitory Effects of Quercetin on Progression of Human Choriocarcinoma Cells Are Mediated Through PI3K/AKT and MAPK Signal Transduction Cascades

As a major dietary flavonol, quercetin mitigates proliferation and progression of cancer due to its anti‐angiogenic, anti‐inflammatory, anti‐oxidant, and apoptotic biological effects on cells. Although its apoptotic effects have been reported for various cancers, little is known of the functional role of quercetin in gestational choriocarcinoma. Results of the present study indicated that quercetin reduced proliferation and induced cell death in two choriocarcinoma cell lines, JAR and JEG3 cells, with an increase in the sub‐G1 phase of the cell cycle. In addition, quercetin induced mitochondrial dysfunction significantly reduced mitochondrial membrane potential (MMP) and increased production of reactive oxygen species (ROS) in both JAR and JEG3 cells. Further, quercetin inhibited phosphorylation of AKT, P70S6K and S6 proteins whereas, it increased phosphorylation of ERK1/2, P38, JNK and P90RSK proteins in JAR and JEG3 cells. The decrease in viability of choriocarcinoma cells treated with quercetin was confirmed by using combinations of quercetin and pharmacological inhibitors of the PI3K and MAPK signaling pathways. Classical chemotherapeutic agents, cisplatin (a platinum‐based drug) and paclitaxel (a taxene‐based drug), inhibited proliferation of JAR and JEG3 cells, and when combined with quercetin, the antiproliferative effects of cisplatin and paclitaxel were enhanced for both choriocarcinoma cell lines. Collectively, these results suggest that quercetin prevents development of choriocarcinoma and may be a valuable therapeutic agent for treatment of choriocarcinoma through its regulation of PI3K and MAPK signal transduction pathways. J. Cell. Physiol. 232: 1428–1440, 2017.

Decanoic acid suppresses proliferation and invasiveness of human trophoblast cells by disrupting mitochondrial function

&NA; Decanoic acid (DA) is a medium‐chain fatty acid used in the manufacture of various products including plastics, cosmetics, and lubricants. In addition to antiviral and antibacterial effects, DAs, reported biological activities include regulation of signaling pathways and redox homeostasis in various human cell types. The influence of DA on functional properties of human trophoblasts, including proliferation, invasion and apoptosis is currently unknown. In the present study, we evaluated the anti‐proliferative and anti‐invasive effects of DA on the human trophoblast cell line HTR8/SVneo. In addition, DA induced oxidative stress, as evidenced by generation of reactive oxygen species (ROS) and induction of lipid peroxidation (LPO). This oxidative stress was accompanied by activation of the mitochondria‐dependent apoptotic pathway in HTR8/SVneo cells. We also observed elevated mitochondrial Ca2 +, and loss of mitochondrial membrane potential in response to DA treatment. Chelation of mitochondrial Ca2 + using BAPTA‐AM rescued cellular proliferation suppressed by DA. We also verified that signaling proteins including AKT, P70S6K, S6, and ERK1/2 and their targets were significantly reduced in HTR8/SVneo cells by DA treatment. Pre‐treatment of cells with selective inhibitors of AKT (LY294002) and ERK1/2 (U0126) revealed that the AKT and ERK1/2 signaling pathways regulated by DA displayed cross‐talk in HTR8/SVneo cells. Collectively, these results suggest that personal products containing DA will have harmful effects on human trophoblasts, and could cause implantation and placentation failure during early pregnancy. HighlightsDecanoic acid inhibits proliferation and invasion of human trophoblasts.Decanoic acid blocks AKT and ERK1/2 signaling pathways in human trophoblasts.Decanoic acid‐induced oxidative stress results in mitochondrial membrane disruption.

Propyl gallate induces cell death and inhibits invasion of human trophoblasts by blocking the AKT and mitogen-activated protein kinase pathways

Propyl gallate (PG) is an antioxidant widely used in food additives, cosmetics, adhesives, and lubricants. PG protects the oils in food products from reacting with hydrogen peroxide and oxygen free radicals, thus preventing spoilage. It is known to have both protective and cytotoxic effects on various cells, but its effects on human trophoblasts remain unclear. Therefore, we investigated the effects of PG on proliferation, apoptosis, and invasiveness of human trophoblasts using an immortalized HTR8/SVneo cell line. We found that PG significantly reduced proliferation of and induced apoptosis in HTR8/SVneo cells. In addition, the invasiveness of HTR8/SVneo cells was attenuated in response to PG. Signaling pathways including the PI3K/AKT and MAPK pathways involved in the proliferation and invasiveness of human trophoblasts were regulated by PG treatment in HTR8/SVneo cells. We confirmed that mitochondrial membrane disruption and Ca2+ overload were markedly elevated in response to PG treatment, suggesting that PG-induced apoptosis is closely related to mitochondrial dysfunction and further PG-induced apoptosis in HTR8/SVneo cells is related to endoplasmic reticulum (ER) stress. Collectively, these results indicate that PG exerts harmful effects on human trophoblasts; therefore, exposure to PG in early pregnancy is predicted to cause abnormal implantation and placental development.

Aquaporin 3 is regulated by estrogen in the chicken oviduct and is involved in progression of epithelial cell-derived ovarian carcinomas

Aquaporins (AQPs) are membrane proteins that passively deliver water across the plasma membrane to play an important role in maintaining cell shape. Members of the AQP family are distributed in most of the tissues in the human body and perform a variety of functions based on the water homeostasis suitable for each organ. However, there is little known about the expression and regulation of AQP family members in chickens. Therefore, we determined the expression of AQPs in various tissues of chickens. Among 13 isotypes, AQP3 was highly expressed in the chicken oviduct. Expression of AQP3 messenger RNA (mRNA) increased in the magnum (P < 0.001) and isthmus (P < 0.001) of chick oviducts treated with diethylstilbestrol. Consistent with these results, the localization of AQP3 was detected in the glandular and luminal epithelia of the magnum and isthmus of oviducts of diethylstilbestrol-treated chicks. In addition, the pattern of expression of AQP3 changed in an estrogen-dependent manner during the molting period. During the regenerative period of the oviduct after molting, expression of AQP3 mRNA increased coordinately with increasing concentrations of estradiol (P < 0.001), whereas expression of AQP3 mRNA decreased as concentrations of estradiol in plasma decreased in response to induced molting (P < 0.001). Also, expression of the AQP3 increased (P < 0.001) in cancerous ovaries of laying hens. In conclusion, AQP3 does not simply function to transport water into and out of cells but also appears to be closely involved in development of the chicken oviduct, which is regulated by estrogens. Furthermore, our results suggest AQP3 as a new diagnostic for early detection and treatment of epithelial cell-derived ovarian carcinomas.

Butyl paraben promotes apoptosis in human trophoblast cells through increased oxidative stress-induced endoplasmic reticulum stress

Butyl paraben (BP) has antimicrobial effects and is widely used as a preservative in cosmetics, foods, and pharmaceuticals. It is also absorbed into various tissues of the human body. It is known that BP is measurable in maternal and fetal tissues during pregnancy, but the effects of BP on placental development, essential for maintaining normal pregnancy, are unclear. Therefore, we investigated the effect of BP on the proliferation, apoptosis, and invasiveness of human trophoblast cells, using an HTR8/SVneo cell line. BP inhibited cell proliferation and induced both apoptosis and endoplasmic reticulum stress. In addition, BP promoted the production of intracellular reactive oxygen species, increased Ca2+ concentration in HTR8/SVneo cells, and induced mitochondrial membrane depolarization. BP also inhibited the activation of PI3K/AKT pathways including AKT, ribosomal protein S6, P70 S6 kinase, and glycogen synthase kinase 3β. Furthermore, pretreatment of cells with LY294002 (an AKT inhibitor) and U0126 (ERK1/2 inhibitor) revealed that ERK1/2 activity is also involved in BP‐mediated signal transduction in HTR8/SVneo cells. We therefore suggest that exposing human trophoblast cells to BP diminishes normal physiological activity, leading to apoptosis and problems with early placental development.

Down-regulation of Stearoyl-CoA Desaturase-1 Increases Susceptibility to Palmitic Acid-Induced Lipotoxicity in Human Trophoblast Cells

In early pregnancy, adequate dietary factors are important for the growth of human trophoblast cells, followed by placental development. Although stearoyl-CoA desaturase 1 (SCD1) is expected to relieve palmitic acid (PA)-induced lipotoxicity by regulating diacylglycerol and ceramide, its function is unclear in human trophoblast cells. The aim was to investigate inhibitory effects of SCD1 activity on PA-induced trophoblast cell death. PA induces cell death and inhibits the invasion of human trophoblast cells (HTR8/SVneo). In addition, we demonstrate that SCD1 has a protective role against PA in human trophoblast cells by regulating AKT-mediated signaling pathway and mitochondrial membrane potential. The knockdown of SCD1 enhances the proapoptotic activity of PA in HTR8/SVneo cells. Lastly, we investigated microRNA expression predicted to target SCD1 and diacylglycerol O-acyltransferase 1 (DGAT1) by PA. Collectively, the results suggest potential roles of SCD1 and DGAT1 in alleviating the toxicity of PA and maintaining lipid homeostasis for normal placentation.

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.).