Revealing the effect of 6-gingerol, 6-shogaol and curcumin on mPGES-1, GSK-3β and β-catenin pathway in A549 cell line.

In our study, anticancer effects of 6-gingerol, 6-shogaol from ginger and curcumin from turmeric were investigated and the results were compared with each other. We aimed to reveal their effects on microsomal prostaglandine E2 synthase 1 (mPGES-1) which is related with cancer progression and inflammation as well as β-catenin and glycogen synthase kinase 3β (GSK-3β) that are the main components of Wnt/GSK3 pathway. As it is known activation of GSK-3β and high levels of mPGES-1 pathway leads to cell proliferation and aggravates cancer progression. Therefore both of them are potential targets for cancer therapy. 6-shogaol and 6-gingerol' s effect on this pathway is not known very well up to now while curcumin that is known as an mPGES-1 inhibitor has anticancer properties via this pathway and many other pathways. Besides being in Zingiberaceae family, ginger's 6-gingerol and 6-shogaol have a molecular similarity with turmeric's curcumin. In our study we investigated their effects using a popular non small lung cancer cell line named A549 which expresses mPGES-1 and has active GSK3β pathway. IL-1β was used for inducing mPGES-1 and enabling the cancer characteristics such as cell proliferation. So compounds that inactivates or decreases the level of these components might be potential anticancer agents. A549 cells were incubated with interleukin 1β (IL-1β) for 24 h in order to maintain mPGES-1 enzyme induction. Experiments were performed both on IL-1β and non-IL-1β group. Real time cell analysis was performed to determine the cytotoxicity. Samples for western blotting and RT-PCR were collected after 24 h incubation with compounds to determine the amount of mPGES-1, GSK-3β, p-GSK-3β, β-catenin protein and mRNA. PGE2 which is the end product of mPGES-1 was measured by using ELISA kit. As a result of cell profile assay, cells exposed to IL-1β proliferate faster than non-IL-1β ones. This shows that induced mPGES-1 might play a role through GSK3β pathway and 24 h IC50 value of 6-shogaol is 62 μM. IL-1β increased protein and mRNA levels of mPGES-1, p-GSK-3β, β-catenin and GSK-3β in control group. Effects of curcumin and 6-shogaol on these parameters were against IL-1β's effect while 6-gingerol was not effective at all. Furthermore, 6-shogaol and curcumin might be effective on GSK3β pathway via lowering PGE2 levels. We saw that 6-shogaol is as effective as curcumin on this pathway and our study shows that 6-shogaol might show its anticancer properties via mPGES-1 and GSK3β pathway. May be these results might used for designing in vivo studies in future.

Eren D ，Betul YM 《-》

Curcumin suppresses interleukin 1beta-mediated microsomal prostaglandin E synthase 1 by altering early growth response gene 1 and other signaling pathways.

Moon Y ，Glasgow WC ，Eling TE 《-》

Curcumin activates Wnt/β-catenin signaling pathway through inhibiting the activity of GSK-3β in APPswe transfected SY5Y cells.

Wnt/β-catenin signaling pathway plays an important role in the genesis and development of Alzheimer's disease. The study aims to investigate the effect of Curcumin on the expression of GSK-3β, β-catenin and CyclinD1 in vitro, which are tightly correlated with Wnt/β-catenin signaling pathway, and also to explore the mechanisms, which will provide a novel therapeutic intervention for treatment of Alzheimer's disease. Plasmid APPswe and BACE1-mychis were transiently co-transfected into SHSY5Y cells by Liposfectamin™2000. The cells were treated with Curcumin at 0, 1.25, 5.0, 20.0 μmol/L for 24 h, or with Curcumin at 5.0 μmol/L for 0, and 12, 24 and 48 h for time course assay. Cell lysates were collected for RT-PCR, Western blot assay and immunofluorescent staining were carried out for detecting the effect of Curcumin on the expression of GSK-3β, β-catenin and CyclinD1. RT-PCR and Western blot results showed that the expression of GSK-3β mRNA and protein significantly decreased in the transfected cells treated with Curcumin, and that the changes were in a dose and time-dependent manner (P<0.05); however, the protein expression of GSK-3β-Ser9 was increased (P<0.05). Meanwhile, the expressions of β-catenin and transcriptional factors CyclinD1 mRNA and protein increased and the changes were also in a dose and time-dependent manner (P<0.05). Immunofluorescent staining results not only confirmed the above changes, but also showed that β-catenin had translocated into the nucleus gradually with the increased dosage of Curcumin. Therefore, GSK-3β is a potential target for treatment of AD. Curcumin could activate the Wnt/β-catenin signaling pathway through inhibiting the expression of GSK-3β and inducing the expression of β-catenin and CyclinD1, which will provide a new theory for treatment of neurodegenerative diseases by Curcumin.

Zhang X ，Yin WK ，Shi XD ，Li Y ... -  《-》

Inhibition of cytoplasmic GSK-3β increases cisplatin resistance through activation of Wnt/β-catenin signaling in A549/DDP cells.

Cisplatin-based chemotherapy is recommended as the first-line therapy for advanced non-small cell lung cancer (NSCLC). However, acquired cisplatin resistance is ubiquitous in patients with NSCLC, but the molecular mechanism of such resistance remains ambiguous. The present study sought to examine the role of the Wnt/β-catenin signaling pathway in cisplatin resistance by assessing the phosphorylation and subcellular distribution of GSK-3β in a human lung adenocarcinoma cell line, A549, and its cisplatin-resistant subline, A549/DDP. Total GSK-3β, phosphorylated GSK-3β(ser9) and phosphorylated GSK-3β(tyr216) in cytoplasmic and nuclear fractions of A549/DDP and A549 cells were examined by western blot analysis. The regulation of cisplatin resistance, apoptosis, β-catenin and survivin protein expression by inhibition of cytoplasmic GSK-3β were determined by MTT assay, flow cytometry analysis, immunofluorescence technique and western blot analysis. In the present study, cytoplasmic levels of p-GSK-3β(ser9) were significantly increased in A549/DDP cells as compared with A549 cells (P<0.01), and these levels were further increased by cisplatin treatment in A549/DDP cells (P<0.01). In contrast, cytoplasmic levels of p-GSK-3β(ser9) were reduced in A549 cells after treatment with cisplatin (P<0.01). However, cytoplasmic levels of p-GSK-3β(tyr216) were significantly decreased in A549/DDP cells as compared with A549 cells (P<0.01), and these levels were further decreased by cisplatin treatment in A549/DDP cells (P<0.01). Conversely, cytoplasmic levels of p-GSK-3β(tyr216) were raised in A549 cells after treatment with cisplatin (P<0.01). Analysis of downstream effectors of the Wnt/β-catenin signaling pathway revealed upregulation of β-catenin and survivin expression in A549/DDP cells treated with cisplatin as compared to untreated cells. In A549 cells, cisplatin treatment decreased the expression of β-catenin and survivin. Furthermore, phosphorylation of GSK-3β at serine 9 by LiCl and transient interference of GSK-3β by siRNA increased β-catenin and survivin protein expression in A549/DDP cells. Low exogenous and endogenous cytoplasmic GSK-3β expression enhanced the IC50 and inhibited apoptosis. In conclusion, activation of the Wnt/β-catenin signaling pathway and upregulated survivin expression due to cytoplasmic GSK-3β inhibition might lead to cisplatin resistance in NSCLC.

Gao Y ，Liu Z ，Zhang X ，He J ，Pan Y ，Hao F ，Xie L ，Li Q ，Qiu X ，Wang E ... -  《-》

MicroRNA-26b inhibits cell proliferation and cytokine secretion in human RASF cells via the Wnt/GSK-3β/β-catenin pathway.

Sun J ，Yan P ，Chen Y ，Chen Y ，Yang J ，Xu G ，Mao H ，Qiu Y ... -  《Diagnostic Pathology》