Impact of Polyphenolic Compounds on the MAPK Signaling Pathway against Carcinogenesis

The Mos protein kinase is a key regulator of vertebrate oocyte maturation. Oocyte-specific Mos protein expression is subject to translational control. In the frog Xenopus, the translation of Mos protein requires the progesterone-induced polyadenylation of the maternal Mos mRNA, which is present in the oocyte cytoplasm. Both the Xenopus p42 mitogen-activated protein kinase (MAPK) and maturation-promoting factor (MPF) signaling pathways have been proposed to mediate progesterone-stimulated oocyte maturation. In this study, we have determined the relative contributions of the MAPK and MPF signaling pathways to Mos mRNA polyadenylation. We report that progesterone-induced Mos mRNA polyadenylation was attenuated in oocytes expressing the MAPK phosphatase rVH6. Moreover, inhibition of MAPK signaling blocked progesterone-induced Mos protein accumulation. Activation of the MAPK pathway by injection of RNA encoding Mos was sufficient to induce both the polyadenylation of synthetic Mos mRNA substrates and the accumulation of endogenous Mos protein in the absence of MPF signaling. Activation of MPF, by injection of cyclin B1 RNA or purified cyclin B1 protein, also induced both Mos protein accumulation and Mos mRNA polyadenylation. However, this action of MPF required MAPK activity. By contrast, the cytoplasmic polyadenylation of maternal cyclin B1 mRNA was stimulated by MPF in a MAPK-independent manner, thus revealing a differential regulation of maternal mRNA polyadenylation by the MAPK and MPF signaling pathways. We propose that MAPK-stimulated Mos mRNA cytoplasmic polyadenylation is a key component of the positive-feedback loop, which contributes to the all-or-none process of oocyte maturation.

The DNA damage response (DDR) network and the mitogen-activated protein kinase (MAPK) signaling pathway are crucial mechanisms for the survival of all living beings. An accumulating body of evidence suggests that there is crosstalk between these two systems, thus favoring the appropriate functioning of multi-cellular organisms. On the other hand, aberrations within these mechanisms are thought to play a vital role in the onset and progression of several diseases, including cancer, as well as in the emergence of drug resistance. Here, we provide an overview of the current knowledge regarding alterations in the DDR machinery and the MAPK signaling pathway as well as abnormalities in the DDR/MAPK functional crosstalk in multiple myeloma, the second most common hematologic malignancy. We also present the latest advances in the development of anti-myeloma drugs targeting crucial DDR- and MAPK-associated molecular components. These data could potentially be exploited to discover new therapeutic targets and effective biomarkers as well as for the design of novel clinical trials. Interestingly, they might provide a new approach to increase the efficacy of anti-myeloma therapy by combining drugs targeting the DDR network and the MAPK signaling pathway.

Geniposide (GE), an iridoid glycoside compound derived from Gardenia jasminoides Ellis fruit, is known to have anti-inflammatory and immunoregulatory activities. The aim of this study was to investigate the protective mechanism of GE in the regulation of the mitogen-activated protein kinase (MAPK) signalling pathway and the cross-talk among the MAPK signalling pathway in fibroblast-like synoviocytes (FLS) of adjuvant arthritis (AA) rats. AA was induced by injecting with Freund’s complete adjuvant. Male SD rats and FLS were subjected to treatment with GE (30, 60 and 120 mg/kg) in vivo from day 14 to 21 after immunization and GE (25, 50 and 100 μg/mL) in vitro, respectively. The proliferation of FLS was assessed by MTT. IL-4, IL-17, IFN-γ, and TGF-β1 were determined by ELISA. Key proteins in the MAPK signalling pathway were detected by Western blot. GE significantly reduced the proliferation of FLS, along with decreased IFN-γ and IL-17 and increased IL-4 and TGF-β1. In addition, GE decreased the expression of p-JNK, p-ERK1/2 and p-p38 in FLS of AA rats. Furthermore, disrupting one MAPK pathway inhibited the activation of other MAPK pathways, suggesting cross-talk among MAPK signalling. In vivo study, it was also observed that GE attenuated histopathologic changes in the synovial tissue of AA rats. Collectively, the mechanisms by which GE exerts anti-inflammatory and immunoregulatory effects may be related to the synergistic effect of JNK, ERK1/2 and p38. Targeting MAPK signalling may be a new therapeutic strategy in inflammatory/autoimmune diseases.

Titanium is widely used in implant materials, while excessive fluoride may have negative effects on the osseointegration between the titanium and osteoblasts. Although the underlying mechanisms are still not clear, the mitogen-activated protein kinase (MAPK) or Yes-associated protein (YAP) signaling pathways are thought to be involved. This study evaluated the role of Hippo/YAP and MAPK signaling pathway in osteoblast behaviors under excessive fluoride exposure in vitro and in vivo. Commercially pure Ti (cp-Ti) samples were exposed to fluoride (0, 0.1, and 1.0mM NaF) for 7days. Cell adhesion was observed using a laser scanning confocal microscope. Cell viability and apoptosis were evaluated by CCK-8 assay and flow cytometry, respectively. The expressions of osteoblast markers and key molecules in MAPK and YAP pathway were detected by Western blot. In vivo studies were evaluated by histology methods in C57/BL6 mice model. Our results showed that 1.0mM NaF destroyed the passivation film on cp-Ti surface, which further inhibited the osteoblast adhesion and spreading. Meanwhile, compared to other groups, 1.0mM NaF led to a remarkable reduction in cell viability (P < 0.05), as well as increased apoptosis (P < 0.05) and downregulation of osteogenesis protein expression (P < 0.05). MAPK and YAP signaling pathways were also activated under 1.0mM NaF exposure, and JNK seemed to regulate YAP phosphorylation in response to NaF impacts on osteoblasts. In vivo fluorosis mouse model further indicated that 100ppm NaF group (high fluoride group) increased bone resorption and inhibited the nuclear translocation of YAP. The osteoblast behaviors were negatively altered under excessive fluoride, and MAPK/JNK axis contributed to YAP signaling activation in regulating NaF-induced osteoblast behaviors. KEY MESSAGES: • Excessive fluoride inhibited osteoblast behaviors and bone formation. • YAP and MAPK signaling pathways were activated in osteoblasts under fluoride exposure. • Fluoride regulated osteoblast behaviors via the cross-talk between YAP and MAPK.

Objective To explore whether hepatitis B virus X protein (HBx) gene specific small interfering RNA (siRNA) enhances the effect of sorafenib promoting liver cancer cell line PLC apoptosis and the possible mechanism.Methods PLC cells were treated with HBx-siRNA or in combination with sorafenib.The level of HBx mRNA was assessed by using real-time quantitative polymerase chain reaction (Real-time PCR).The apoptosis rate was detected by using flow cytometry.The changes in genes profiles of mitogen-activated protein kinase (MAPK) signal pathway before and after treatment with HBx-siRNA in combination with sorafenib in PLC cells were observed by using real-time gene array.Results After treatment with HBx-siRNA for 24 h,the expression of HBx mRNA in PLC cells was decreaseed significantly to 0.61 (P ＜ 0.05).HBx-specific siRNA could enhance apoptosis of PLC cells significantly (P ＜ 0.05) and the apoptosis rate was 43％.After treatment with sorafenib in PLC cells,the expression of two genes was increased to more than two times,and that of 11 decreased to below 0.5 times in the MAPK signal pathway by using real-time PCR array.After HBx siRNA and treatment with sorafenib,the expression of one gene was increased to more than two times,and that of 37 decreased to below 0.5 times in the MAPK signal pathway by using real-time PCR array.Conclusion HBx-si RNA suppresses Hbx gene expression and enhances the response of PLC cells to sorafenib.The mechanism is related to more systemic inhibitory effect on MAPK signal pathway. Key words: Hepatitis B virus ; Small interfering RNA ; Sorafenib ; Carcinoma, hepatocellular; Mitogen-activated protein kinase signal pathway

Breast cancer is one of the most common cancers and leading causes of death in the women worldwide. The evidence shows efficacy of apatinib against breast cancer. Accordingly, the present study was conducted to investigate the effect of apatinib on apoptosis, cell cycle, and Mitogen‑Activated Protein Kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways in the breast cancer MDA-MB-231 cell line. The effects of apatinib on viability, morphology, tumor spheroid, cell cycle, migration, invasion, and apoptosis of MDA-MB-231 breast cancer cells were evaluated in vitro. In addition, expression of proteins involved in NF-κB and MAPK signaling pathways was evaluated using the western blotting analysis. Apatinib decreased viability, tumor spheroid, migration, and invasion of MDA-MB-231 cells. Furthermore, apatinib altered morphology and regulated cell cycle which followed by apoptosis induction in MDA-MB-231 cells. Apatinib decreased expression of p-p65 and p65 proteins in NF-κB signaling pathways and increased expression of p38, p-p38, JNK, and p-JNK in MAPK signaling pathways. The results suggested that apatinib can inhibit proliferation, migration and invasion of breast cancer cell line MDA-MB-231 through inducing apoptosis, cell cycle arrest, and regulating NF-κB and MAPK signaling pathways.

We aimed to investigate the association of macrophage inflammatory protein (MIP)-1α (CCL3) expression with the severity of acute pancreatitis (AP). The patients with AP were selected and divided into mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP) groups according to the severity of AP. The pancreatic acinar cell line Ar42 j was treated with cerulein to induce in vitro cell AP model. The expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and the activation of the c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) signaling pathway in stimulated or transfected Ar42 j cells were detected. We detected that the upregulation of MIP-1α was associated with the severity of AP. Patients with SAP showed the highest MIP-1α contents, followed by MSAP, and, lastly, MAP. In cerulein-stimulated Ar42 j cells, the upregulation of MIP-1α, CCR5, TNF-α, and IL-6 was time dependent. In addition, in human recombinant MIP-1α treated Ar42 j cells, the upregulation of TNF-α and IL-6 was MIP-1α-dose-dependent. In contrast, we detected the inhibition of TNF-α and IL-6 in MIP-1α small interfering RNA (siRNA)-treated cells. Also, the activation of the JNK/p38 MAPK signaling pathway was induced and inhibited by human recombinant MIP-1α and MIP-1α siRNA, respectively. These results suggested that MIP-1α might be used as a biomarker for the prognosis of AP severity. The MIP-1α-induced inflammatory responses in AP were mediated by TNF-α and IL-6, which were associated with the activation of the JNK/p38 MAPK signaling pathway.

Objective To explore the expression and clinical significance of microRNA(miR)-155 and miR-222 in plasma of patients with ventricular septal defect(VSD), and to analyze the possible mechanism. Methods A total of 20 children with VSD who received treatment at the Department of Cardiovascular Surgery from August 2012 to June 2013 were enrolled (the VSD group) and 15 patients with fracture (the control group). The plasma miR-155 and miR-222 expression levels were measured by real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The potential target genes of miR-155 and miR-222 were predicted by using 3 currently available prediction programs, including TargetScan, mirbase and Miranda, and the signaling pathway of miRNA was predicted by Pathway-express analysis. Results Compared with the control group, the expression levels of miR-155(P=0.033) and miR-222(P<0.001) in the VSD group decreased significantly; miR-155 and miR-222 predicted target genes included 74 and 50, respectively.The Pathway-express analysis indicated that 7 signaling pathways played important roles in the occurrence of fetal VSD, including signaling pathways for heart development, such as: mitogen-activated protein kinase(MAPK) signaling pathway. Conclusions The expression levels of plasma miR-155 and miR-222 in VSD were significantly decreased.The target genes were related to signaling pathways for heart deve-lopment (MAPK signaling pathway), which indicates that miR-155 and miR-222 may be involved in the pathological process of VSD, and may serve as an independent evaluation indicator for the diagnosis of VSD. Key words: microRNA; Ventricular septal defect; Mitogen-activated protein kinase signaling pathway

Mitogen-activated protein kinase (MAPK) signaling pathways may be involved in various activities of cells such as apoptosis, differentiation and autophagy. In human cells, MAPK signaling pathways mainly contain Erk, p38 MAPK and JNK, and each of them is highly specific and has its own function. MAPK signaling pathways are closely related to the development of leukemia. The effect of MAPK signaling pathways on leukemia cells is mainly mediated by affecting cell apoptosis, cell drug resistant , cell autophagy and differentiation. In this review, recent advances on the study of MAPK in leukemia are reviewed. Key words: JNK pathway; p38 pathway; Erk pathway; Leukemia

N-acetylated proline-glycine-proline (N-Ac-PGP) is a chemokine involved in inflammatory diseases and is found to accumulate in degenerative discs. N-Ac-PGP has been demonstrated to have a pro-inflammatory effect on human cartilage endplate stem cells. However, the effect of N-Ac-PGP on human intervertebral disc cells, especially nucleus pulposus (NP) cells, remains unknown. The purpose of this study was to investigate the effect of N-Ac-PGP on the expression of pro-inflammatory factors and extracellular matrix (ECM) proteases in NP cells and the molecular mechanism underlying this effect. Therefore, Milliplex assays were used to detect the levels of various inflammatory cytokines in conditioned culture medium of NP cells treated with N-Ac-PGP, including interleukin-1β (IL-1β), IL-6, IL-17, tumor necrosis factor-α (TNF-α) and C-C motif ligand 2 (CCL2). RT-qPCR was also used to determine the expression of pro-inflammatory cytokines and ECM proteases in the NP cells treated with N-Ac-PGP. Moreover, the role of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in mediating the effect of N-Ac-PGP on the phenotype of NP cells was investigated using specific signaling inhibitors. Milliplex assays showed that NP cells treated with N-Ac-PGP (10 and 100 µg/ml) secreted higher levels of IL-1β, IL-6, IL-17, TNF-α and CCL2 compared with the control. RT-qPCR assays showed that NP cells treated with N-Ac-PGP (100 µg/ml) had markedly upregulated expression of matrix metalloproteinase 3 (MMP3), MMP13, a disintegrin and metalloproteinase with thrombospondin motif 4 (ADAMTS4), ADAMTS5, IL-6, CCL-2, CCL-5 and C-X-C motif chemokine ligand 10 (CXCL10). Moreover, N-Ac-PGP was shown to activate the MAPK and NF-κB signaling pathways in NP cells. MAPK and NF-κB signaling inhibitors suppressed the upregulation of proteases and pro-inflammatory cytokines in NP cells treated with N-Ac-PGP. In conclusion, N-Ac-PGP induces the expression of pro-inflammatory cytokines and matrix catabolic enzymes in NP cells via the NF-κB and MAPK signaling pathways. N-Ac-PGP is a novel therapeutic target for intervertebral disc degeneration.

Introduction: The Nef-M1 peptide competes effectively with the natural ligand of CXCR4, SDF-1α, to induce apoptosis and inhibit growth in colon and breast cancers. Its mechanistic role in tumor angiogenesis, a key step involved in tumor growth and metastasis, is unknown. In this study, we evaluated the antiangiogenic effect of Nef-M1 and examined its role in the AKT and Mitogen-Activated Protein Kinase (MAPK) signaling pathways in colon cancer. Experimental Design: We studied HT29 and SW480 colon cancer cells in vitro and tumor xenografts developed from HT29 cells were propagated in severe combined immunodeficient mice in vivo. The mice were treated intraperitoneally with the Nef-M1 peptide or sNef-M1 (scramble peptide as control) starting at the time of tumor implantation. Sections from tumors were evaluated for tumor angiogenesis, as measured by microvessel density (MVD) based on immunostaining of endothelial markers (CD31 and FVIII-RAg). MVD was determined by light microscopy in areas of invasive tumor containing the highest numbers of microvessels per area. Individual microvessel counts were made on a 200x field within the areas of most intense tumor neovascularization. Western blot analyses were performed on lysates of both colon cancer cell lines and HT-29 tumors to assess the effect of Nef-M1 on the AKT, and MAPK signaling pathways. Results: Immunostaining analyses indicated that control tumors had well established vascularity, but Nef-M1 treated tumors had poor vascularization. In addition, the average MVD was reduced in Nef-M1 treated tumors (n=5) compared to sNef-M1 control tumors (n=12) (p&amp;lt;0.05). In Nef-M1 treated tumors, the average microvessel size was significantly decreased from 2.28μm2 to 1.16μm2. Western blot analyses of lysates of colon cancer cells and tumors revealed that Nef-M1 effectively suppressed the activation of p38 and extracellular signal-regulated kinase (ERK) MAP kinases. AKT activation was also inhibited in Nef-M1 treated samples of colon cancer cells and tumor xenografts. This inhibition was accompanied by down-regulation of phosphorylated glycogen synthase kinase-3β (p-GSK-3β), a downstream target of p-AKT. Conclusions: Our data suggest that Nef-M1 inhibits tumor angiogenesis by attenuating AKT and MAPK signaling pathways and that, by targeting chemokine receptor CXCR4 mediated pathways, it may be a novel therapeutic agent for colon cancers. This work was supported by NIH/NCI Workforce Diversity Grant R21-CA171251. Citation Format: Venkat R. Katkoori, Marc D. Basson, Upender Manne, Harvey L. Bumpers. Nef-M1, a peptide antagonist of CXCR4, inhibits tumor angiogenesis by attenuating AKT and mitogen-activated protein kinase signaling in colon cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1027. doi:10.1158/1538-7445.AM2014-1027

Objective: The aim of this study was to investigate the effect of mitogen-activated protein kinase (MAPK) signaling pathway on apoptosis induced by chloroacetic acid in human normal bronchial epithelial 16HBE cells. Methods: 16HBE cells were exposed to 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 mmol/L chloroacetic acid for 24 h in vitro. The cytotoxicity induced by chloroacetic acid was assessed by CCK-8 and LDH assays. Cell apoptosis was detected by Annexin V-FITC and PI staining. The protein expression levels of phosphorylation of p38, ERK1/2 and JNK were determined by western blotting. 16HBE cells were pretreated with MAPK signaling pathway specific inhibitors including SB203580, U0126 and SP600125 for 1 h, and these cells were subsequently treated with 2.5 mmol/L chloroacetic acid for 24 h. The expressions of p-p38, p-ERK1/2 and p-JNK as well as the changes of cell viability and apoptosis were measured after pretreated with inhibitors for 1 h. Results: The cell viability by CCK-8 and LDH methods gradually reduced in a dose-dependent manner when chloroacetic acid concentrations elevated (P<0.05) , and their correlation coefficients were -0.902 and -0.825, respectively. The detection efficiency of CCK-8 assay significantly increased compared with LDH assay (P<0.05) . The cell apoptosis rates, which were (17.2±4.0) %, (24.6± 4.2) %, (39.3 ± 5.7) % in 1.5, 2.0, 2.5 mmol/L chloroacetic acid-treated groups, were higher than that of the control group[ (5.6 ± 3.0) %] (P<0.05) . There was a time-or dose-dependent change in the protein expressions of p-p38, p-ERK1/2 and p-JNK. Compared with the control, the levels of p-p38 had 2.1 and 2.6-fold increases in 16 and 24 h treated groups (P<0.01) , while the levels of p-ERK1/2 distinctly decreased by 37% and 52% (P<0.01) . In comparison with the control group, the expressions of p-p38 had 1.9 and 2.6-fold increases in 1.5 and 2.5 mmol/L treatment groups (P<0.01) , whereas the expressions of p-ERK1/2 significantly decreased by 40% and 50% (P<0.01) . No significant change was observed in p-JNK protein expression between the chloroacetic acid-treated and control groups. In comparison with the vehicle control and the exposed group, p-p38, p-ERK1/2, p-JNK protein expressions significantly declined in the inhibitor controls and inhibitor groups. Compared with the controls, the cell survival rates had significant reductions of 28%, 18%, 36% and 26% respectively in chloroacetic acid treated group, SB203580 group, U0126 group and SP600125 group, and the apoptosis rates in the abovementioned groups were 7, 4, 8 and 7 times. Compared with chloroacetic acid-treated group, the cell viability increased by 14% in SB203580 group and decreased by 11% in U0126 group, and the cell apoptosis rates decreased by 36% in SB203580 group and increased by 18% in U0126 group (P<0.05) . But no significant changes were observed in cell viability and apoptosis between SP600125 and chloroacetic acid-treated group. Conclusion: Chloroacetic acid might activate p38 MAPK signaling pathway and inhibit ERK1/2 MAPK signaling pathway. The signaling pathways of p38 and ERK1/2 MAPK are involved in 16HBE cell apoptosis induced by chloroacetic acid, but JNK is not involved in chloroacetic acid-induced 16HBE cell apoptosis.

Fleshy fruit ripening is a unique biological process that involves dramatic changes in a diverse array of cellular metabolisms. The regulation of these metabolisms is essentially mediated by cellular signal transduction of internal (e.g., hormones) and external cues (i.e., environmental stimuli). Mitogen-activated protein kinase (MAPK) signaling pathways play crucial roles in a diverse array of biological processes, such as plant growth, development and biotic/abiotic responses. Accumulating evidence suggests that MAPK signaling pathways are also implicated in fruit ripening and quality formation. However, while MAPK signaling has been extensively reviewed in Arabidopsis and some crop plants, the comprehensive picture of how MAPK signaling regulates fruit ripening and quality formation remains unclear. In this review, we summarize and discuss research in this area. We first summarize recent studies on the expression patterns of related kinase members in relation to fruit development and ripening and then summarize and discuss the crucial evidence of the involvement of MAPK signaling in fruit ripening and quality formation. Finally, we propose several perspectives, highlighting the research matters and questions that should be afforded particular attention in future studies.

Kava (Piper methysticum Foster, Piperaceae) organic solvent-extract has been used to treat mild to moderate anxiety, insomnia, and muscle fatigue in Western countries, leading to its emergence as one of the 10 best-selling herbal preparations. However, several reports of severe hepatotoxicity in kava consumers led the U.S. Food and Drug Administration and authorities in Europe to restrict sales of kava-containing products. Herein we demonstrate that flavokawain B (FKB), a chalcone from kava root, is a potent hepatocellular toxin, inducing cell death in HepG2 (LD50=15.3±0.2 µM) and L-02 (LD50=32 µM) cells. Hepatocellular toxicity of FKB is mediated by induction of oxidative stress, depletion of reduced glutathione (GSH), inhibition of IKK activity leading to NF-κB transcriptional blockade, and constitutive TNF-α-independent activation of mitogen-activated protein kinase (MAPK) signaling pathways, namely, ERK, p38, and JNK We further demonstrate by noninvasive bioluminescence imaging that oral consumption of FKB leads to inhibition of hepatic NF-κB transcriptional activity in vivo and severe liver damage. Surprisingly, replenishment with exogenous GSH normalizes both TNF-α-dependent NF-κB as well as MAPK signaling and rescues hepatocytes from FKB-in-duced death. Our data identify FKB as a potent GSH-sensitive hepatotoxin, levels of which should be specifically monitored and controlled in kava-containing herb products.—Zhou, P., Gross, S., Liu, J.-H., Yu, B.-Y., Feng, L.-L., Nolta, J., Sharma, V., Piwnica-Worms, D., Qiu, S. X. Flavokawain B, the hepatotoxic constituent from kava root, induces GSH-sensitive oxidative stress through modulation of IKK/NF-κB and MAPK signaling pathways. FASEB J. 24, 4722–4732 (2010). www.fasebj.org

Unraveling the molecular landscape: a comparative analysis of PI3K and MAPK signaling pathways in plasmablastic lymphoma and diffuse large B-cell lymphoma with therapeutic implications