MicroRNA miR-181d-5p regulates the MAPK signaling pathway by targeting mitogen-activated protein kinase 8 (MAPK8) to improve lupus nephritis

BACKGROUND

Lupus nephritis (LN) is a common immune disease. The microRNA (miR)-181d-5p is a potential target for treating kidney injury. However, the therapeutic role of miR-181d-5p in LN has not been investigated. This study aimed to investigate the role of miR-181d-5p in targeting mitogen-activated protein kinase 8 (MAPK8) and stimulating the MAPK signaling pathway in LN.

METHODS

RT-qPCR was performed to identify the variations in miR-181d-5p expression in peripheral blood mononuclear cells (PBMCs) obtained from 42 LN patients, 30 healthy individuals, 6 MRL/lpr mice and 6 C57BL/6 mice. Western blot was used to detect the effect of miR-181d-5p on the MAPK signaling pathway in THP-1 cells and MRL/lpr mice. Enzyme-linked immunosorbent assay (ELISA) was utilized to detect the effect of miR-181d-5p on antinuclear antibodies and inflammatory factors. A dual-luciferase reporter assay was used to verify whether miR-181d-5p directly targets MAPK8. Flow cytometry was performed to evaluate apoptosis rates in transfected THP-1 cells.

RESULTS

miR-181d-5p expression was downregulated in PBMCs of LN patients (P < 0.01) and MRL/lpr mice (P < 0.05). A dual luciferase reporter assay demonstrated that miR-181d-5p inhibits MAPK8 (P < 0.01). Overexpression of miR-181d-5p inhibited the phosphorylation of p38 (P < 0.001) and p44/42 (P < 0.01). Moreover, miR-181d-5p decreased the apoptosis rate of THP-1 cells (P < 0.001), and reduced the secretion of IL-6 (P < 0.01) and TNF-α (P < 0.01). Furthermore, overexpression of miR-181d-5p decreased anti-dsDNA antibody (P < 0.05), anti-Sm antibody (P < 0.01), and fibrosis levels in MRL/lpr mice.

CONCLUSION

Upregulation of miR-181d-5p showed anti-inflammatory and anti-apoptotic effects on THP-1 cells in vitro and kidney injury in vivo. These effects were achieved by miR-181d-5p targeting MAPK8 to inhibit phosphorylation of p38 and p44/42. These results may offer new insights for improving therapeutic strategies against lupus nephritis.

MiR-130a-3p inhibits endothelial inflammation by regulating the expression of MAPK8 in endothelial cells

MicroRNA-130a-3p (miR-130a-3p) has been reported as closely related to atherosclerosis (AS). This study is to survey the effects of miR-130a-3p in endothelial cells (ECs) treated with oxidized low-density lipoprotein (ox-LDL) and explore underlying mechanisms. The proliferation and apoptosis of ox-LDL-treated HUVEC cells were determined by CCK-8, EdU, and flow cytometry assays. ELISA and Western blot analysis measured the expressions of cytokines and protein levels. Bioinformatics and dual-luciferase reporter assay were performed to predict and confirm that Mitogen-activated protein kinase 8 (MAPK8) was a direct target of miR-130a-3p, and MAPK8 was negatively associated with miR-130a-3p. As expected, miR-130a-3p was down-regulated in ox-LDL-treated HUVEC cells, and up-regulation of miR-130a-3p promoted proliferation and inhibited apoptosis of ox-LDL-treated HUVEC cells. Furthermore, miR-130a-3p mimics suppressed the expressions of TNF-α and IL-6 and decreased the protein levels of VCAM-1, ICAM-1 and E-selectin. MAPK8 was highly expressed in ox-LDL-treated HUVEC cells, and silence of MAPK8 promoted proliferation inhibited apoptosis, suppressed inflammatory responses, and decreased the levels of VCAM-1, ICAM-1, and E-selectin, over-expression of MAPK8 partially restored the functional effects of miR-130a-3p on proliferation, inflammatory responses, and the expressions of VCAM-1, ICAM-1 and E-selectin. This study indicates that miR-130a-3p may emerge as an effective target for treating AS.

Polymorphisms in genes of melatonin biosynthesis and signaling support the light-at-night hypothesis for breast cancer

Light-at-night triggers the decline of pineal gland melatonin biosynthesis and secretion and is an IARC-classified probable breast-cancer risk factor. We applied a large-scale molecular epidemiology approach to shed light on the putative role of melatonin in breast cancer. We investigated associations between breast-cancer risk and polymorphisms at genes of melatonin biosynthesis/signaling using a study population of 44,405 women from the Breast Cancer Association Consortium (22,992 cases, 21,413 population-based controls). Genotype data of 97 candidate single nucleotide polymorphisms (SNPs) at 18 defined gene regions were investigated for breast-cancer risk effects. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CI) by logistic regression for the main-effect analysis as well as stratified analyses by estrogen- and progesterone-receptor (ER, PR) status. SNP-SNP interactions were analyzed via a two-step procedure based on logic regression. The Bayesian false-discovery probability (BFDP) was used for all analyses to account for multiple testing. Noteworthy associations (BFDP < 0.8) included 10 linked SNPs in tryptophan hydroxylase 2 (TPH2) (e.g. rs1386492: OR = 1.07, 95% CI 1.02-1.12), and a SNP in the mitogen-activated protein kinase 8 (MAPK8) (rs10857561: OR = 1.11, 95% CI 1.04-1.18). The SNP-SNP interaction analysis revealed noteworthy interaction terms with TPH2- and MAPK-related SNPs (e.g. rs1386483R ∧ rs1473473D ∧ rs3729931D: OR = 1.20, 95% CI 1.09-1.32). In line with the light-at-night hypothesis that links shift work with elevated breast-cancer risks our results point to SNPs in TPH2 and MAPK-genes that may impact the intricate network of circadian regulation.

MAPK8 and CAPN1 as potential biomarkers of intervertebral disc degeneration overlapping immune infiltration, autophagy, and ceRNA

Background

Intervertebral disc degeneration (IDD) is one of the most common health problems in the elderly and a major causative factor in low back pain (LBP). An increasing number of studies have shown that IDD is closely associated with autophagy and immune dysregulation. Therefore, the aim of this study was to identify autophagy-related biomarkers and gene regulatory networks in IDD and potential therapeutic targets.

Methods

We obtained the gene expression profiles of IDD by downloading the datasets GSE176205 and GSE167931 from the Gene Expression Omnibus (GEO) public database. Subsequently, differentially expressed genes (DEGs) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene ontology (GO), and gene set enrichment analysis (GSEA) were performed to explore the biological functions of DEGs. Differentially expressed autophagy-related genes (DE-ARGs) were then crossed with the autophagy gene database. The hub genes were screened using the DE-ARGs protein-protein interaction (PPI) network. The correlation between the hub genes and immune infiltration and the construction of the gene regulatory network of the hub genes were confirmed. Finally, quantitative PCR (qPCR) was used to validate the correlation of hub genes in a rat IDD model.

Results

We obtained 636 DEGs enriched in the autophagy pathway. Our analysis revealed 30 DE-ARGs, of which six hub genes (MAPK8, CTSB, PRKCD, SNCA, CAPN1, and EGFR) were identified using the MCODE plugin. Immune cell infiltration analysis revealed that there was an increased proportion of CD8+ T cells and M0 macrophages in IDD, whereas CD4+ memory T cells, neutrophils, resting dendritic cells, follicular helper T cells, and monocytes were much less abundant. Subsequently, the competitive endogenous RNA (ceRNA) network was constructed using 15 long non-coding RNAs (lncRNAs) and 21 microRNAs (miRNAs). In quantitative PCR (qPCR) validation, two hub genes, MAPK8 and CAPN1, were shown to be consistent with the bioinformatic analysis results.

Conclusion

Our study identified MAPK8 and CAPN1 as key biomarkers of IDD. These key hub genes may be potential therapeutic targets for IDD.

miR-29a-3p promotes the regulatory role of eicosapentaenoic acid in the NLRP3 inflammasome and autophagy in microglial cells

Eicosapentaenoic acid (EPA) has been reported to play an anti-inflammatory and antioxidative stress role in a series of human diseases, including major depressive disorder. However, its exact mechanism is still largely unknown. Mouse BV-2 cells were treated with lipopolysaccharide (LPS) to induce an in vitro inflammatory cell model of depression. Cytotoxic effects were assessed with MTT and lactate dehydrigebase release assays. Cytokine mediators were elevated by western blot and enzyme-linked immunosorbent assays. Autophagy-relators were determined by immunofluorescence and western blot analyses. Interaction relationships among molecules were evaluated utilizing chromatin immunoprecipitation and dual luciferase assays. Methylated miR-29a-3p was detected via methylation-specific polymerase chain reaction. EPA treatment at 60 μM had no cytotoxic effects on BV2 cells and significantly inhibited the LPS-induced inflammatory response and NLRP3 inflammasome but activated autophagy, while all these effects were reversed by the autophagy inhibitor 3-MA. Importantly, miR-29a-3p exhibited a role similar to that of EPA in LPS-treated BV2 cells. Mechanistically, EPA treatment elevated miR-29a-3p by repressing its promoter methylation. MAPK8 was a direct target of miR-29a-3p. Inhibition of miR-29a-3p greatly diminished the regulatory roles mediated by EPA in LPS-treated BV2 cells, while these roles were further impeded after MAPK8 silencing. To conclude, our data demonstrated that EPA treatment alleviated LPS-induced NLRP3 inflammasomes by activating autophagy via regulation of miR-29a-3p/MAPK8 signaling, which further elucidates the potential antidepressant mechanism of EPA.

Silencing of UCA1 attenuates the ox-LDL-induced injury of human umbilical vein endothelial cells via miR-873-5p/MAPK8 axis

LncRNA UCA1 plays a vital role in cardiovascular diseases. Endothelial cell dysfunction is a prerequisite for atherosclerosis (AS) development. However, the pathophysiological role of UCA1 in endothelial cell dysfunction induced by ox-LDL remains obscure. Here, we observed that UCA1 was upregulated in the sera of patients with AS and ox-LDL-treated endothelial cells. UCA1 knockdown dramatically reduced the cell apoptosis induced by ox-LDL and the production of pro-inflammatory cytokines and ROS in endothelial cells. Mechanistically, we found that UCA1 directly targeted miR-873-5p. UCA1 knockdown increased, while UCA1 overexpression decreased the expression of miR-873-5p. Further, we found that mitogen-activated protein kinase 8 (MAPK8) was a downstream target gene of miR-873-5p. MAPK8 overexpression or miR-873-5p knockdown reduced the enhancement of ox-LDL-induced cell apoptosis, oxidative stress, and pro-inflammatory cytokine production conferred by UCA1 knockdown. In conclusion, UCA1 can protect Human Umbilical Vein Endothelial Cells from ox-LDL-induced injury via the miR-873-5p/MAPK8 axis.

Effect of Diallyl Trisulfide on TNF-α-induced CCL2/MCP-1 Release in Genetically Different Triple-negative Breast Cancer Cells

BACKGROUND/AIM

Diallyl trisulfide (DATS) has been shown to prevent and inhibit breast carcinogenesis. CCL2/MCP-1 has been shown to play a significant role in breast cancer. This study explored DATS efficacy on triple-negative breast cancer (TNBC) cells.

MATERIALS AND METHODS

DATS efficacy on TNF-α induced TNBC cells were examined via trypan blue exclusion test, wound-healing assay, human cytokine arrays, ELISA, and RT-PCR.

RESULTS

DATS significantly induced cell death and inhibited cell migration. Expression of CCL2/MCP-1, IL-6, PDGF-BB, NT-3, and GM-CSF in TNF-α-treated cells increased. However, DATS significantly decreased the expression of CCL2/MCP-1 in TNF-α-treated MDA-MB-231 but not in MDA-MB-468 cells. DATS significantly down-regulated mRNA expression of IKBKE and MAPK8 in both cell lines, indicating a possible effect in genes involved in the NF-κB and MAPK signaling.

CONCLUSION

DATS may have a role in TNBC therapy and prevention by targeting CCL2.

CircMED13L_012 promotes lung adenocarcinoma progression by upregulation of MAPK8 mediated by miR-433-3p

Background

Metastasis and disease refractoriness remain as major challenges for non-small cell lung cancer (NSCLC) treatment and understanding the underlying molecular mechanisms is of scientific and clinical value. Therefore, in this study, we aimed to explore the effects of circMED13L_012 on the proliferation, migration, invasion and drug-resistance of NSCLC tumor cells.

Methods

In this study, we utilized clinical samples and NSCLC cell lines to explore the association between circMED13L_012 expressions and tumor cell metastasis and chemo resistance. CCK8 and transwell assay were conducted to explore the impact of circMED13_012 on NSCLC tumor proliferation and migrative capabilities. Dual-luciferase reporter gene assay was conducted to validate the circMED13L_012 interaction network.

Results

Our results demonstrated that circMED13L_012 exhibited significantly elevated average level in our clinical samples of NSCLC, compared with normal tissues. circMED13L_012 level was positively correlated with disease stage and metastatic status. Increased circMED13L_012 expression was associated with the enhanced migration, proliferation and chemo resistance of NSCLC cell lines. Further experiments indicated that circMED13L_012 promoted malignant behavior of NSCLC tumor cells by targeting MAPK8 through modulation miR-433-3p expression.

Conclusions

Our study for the first time demonstrated that circMED13L_012–miR-433-3p–MAPK8 axis played important role for NSCLC pathogenesis, which could be potential therapeutic target for the development of future NSCLC treatment.

In silico and in vitro investigations on the protein-protein interactions of glutathione S-transferases with mitogen-activated protein kinase 8 and apoptosis signal-regulating kinase 1

Cytosolic glutathione S-transferase (GST) enzymes participate in several cellular processes in addition to facilitating glutathione conjugation reactions that eliminate endogenous and exogenous toxic compounds, especially electrophiles. GSTs are thought to interact with various kinases, resulting in the modulation of apoptotic processes and cellular proliferation. The present research used a combination of in silico and in vitro studies to investigate protein-protein interactions between the seven most abundant cytosolic GSTs-GST alpha-1 (GST-A1), GST alpha-2 (GST-A2), GST mu-1 (GST-M1), GST mu-2 (GST-M2), GST mu-5 (GST-M5), GST theta-1 (GST-T1) and GST pi-1 (GST-P1)-and Mitogen-activated protein kinase 8 (MAPK8) and Apoptosis signal-regulating kinase 1 (ASK1). MAPK8 and ASK1 were chosen as this study's protein interaction partners because of their predominant role in electrophile or cytokine-induced stress-mediated apoptosis, inflammation and fibrosis. The highest degree of sequence homology or sequence similarity was observed in two GST subgroups: the GST-A1, GST-A2 and GST-P1 isoforms constituted subgroup1; the GST-M1, GST-M2 and GST-M5 isoforms constituted subgroup 2. The GST-T1 isoform diverged from these isoforms. In silico investigations revealed that GST-M1 showed a significantly higher binding affinity to MAPK8, and its complex was more structurally stable than the other isoforms, in the order GST-M1 > GST-M5 > GST-P1 > GST-A2 > GST-A1 > GST-M2 > GST-T1. Similarly, GST-A1, GST-P1 and GST-T1 actively interacted with ASK1, and their structural stability was also better, in the order GST-T1 > GST-A1 > GST-P1 > GST-A2 > GST-M5 > GST-M1 > GST-M2. To validate in silico results, we performed in vitro crosslinking and mass spectroscopy experiments. Results indicated that GST-M1 interacted with GST-T1 to form heterodimers and confirmed the predicted interaction between GST-M1 and MAPK8.Communicated by Ramaswamy H. Sarma.

Tamoxifen induces fatty liver disease in breast cancer through the MAPK8/FoxO pathway

BACKGROUND

Prevention of metabolic complications of long-term adjuvant endocrine therapy in breast cancers remained a challenge. We aimed to investigate the molecular mechanism in the development of tamoxifen (TAM)-induced fatty liver in both estrogen receptor (ER)-positive and ER-negative breast cancer.

METHODS AND RESULTS

First, the direct protein targets (DPTs) of TAM were identified using DrugBank5.1.7. We found that mitogen-activated protein kinase 8 (MAPK8) was one DPT of TAM. We identified significant genes in breast cancer and fatty liver disease (FLD) using the MalaCards human disease database. Next, we analyzed the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of those significant genes in breast cancer and FLD using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). We found that overlapping KEGG pathways in these two diseases were MAPK signaling pathway, Forkhead box O (FoxO) signaling pathway, HIF-1 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and PI3K-Akt signaling pathway. Furthermore, the KEGG Mapper showed that the MAPK signaling pathway was related to the FoxO signaling pathway. Finally, the functional relevance of breast cancer and TAM-induced FLD was validated by Western blot analysis. We verified that TAM may induce fatty liver in breast cancer through the MAPK8/FoxO signaling pathway.

CONCLUSION

Bioinformatics analysis combined with conventional experiments may improve our understanding of the molecular mechanisms underlying side effects of cancer drugs, thereby making this method a new paradigm for guiding future studies on this issue.

Role of the MAPK/cJun NH2-terminal kinase signaling pathway in starvation-induced autophagy

Autophagy is required for cellular homeostasis and can determine cell viability in response to stress. It is established that MTOR is a master regulator of starvation-induced macroautophagy/autophagy, but recent studies have also implicated an essential role for the MAPK8/cJun NH₂-terminal kinase 1 signal transduction pathway. We found that MAPK8/JNK1 and MAPK9/JNK2 were not required for autophagy caused by starvation or MTOR inhibition in murine fibroblasts and epithelial cells. These data demonstrate that MAPK8/9 has no required role in starvation-induced autophagy. We conclude that the role of MAPK8/9 in autophagy may be context-dependent and more complex than previously considered.

Abbreviations: AKT: thymoma viral proto-oncogene;ALB: albumin; ATG4: autophagy related 4; BCL2: B cell leukemia/lymphoma 2; BECN1: beclin 1, autophagy related; BNIP3: BCL2/adenovirus E1B interacting protein 3; CQ: chloroquine diphosphate; DMEM: Dulbecco’s modified Eagle’s medium; EDTA: ethylenediaminetetraacetic acid; EBSS: Earle’s balanced salt solution; FBS: fetal bovine serum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HRAS: Harvey rat sarcoma virus oncogene; IgG: Immunoglobulin G; MAPK3/ERK1: mitogen-activated protein kinase 3; MAPK8/JNK1: mitogen-activated protein kinase 8; MAPK9/JNK2: mitogen-activated protein kinase 9; MAPK10/JNK3: mitogen-activated protein kinase 10; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MEFs: mouse embryonic fibroblasts; MTOR: mechanistic target of rapamycin kinase; RPS6KB1/p70: ribosomal protein S6 kinase, polypeptide 1; PPARA: peroxisome proliferator activated receptor alpha; SEM: standard error of the mean; SQSTM1/p62: sequestosome 1; TORC1: target of rapamycin complex 1; TORC2: target of rapamycin complex 2; TRP53: transforming related protein 53; TUBA: tubulin alpha; UV: ultraviolet; WT: wild-type

MAPK8 mediates resistance to temozolomide and apoptosis of glioblastoma cells through MAPK signaling pathway

OBJECTIVE

In this study, we aimed to evaluate the expression and functions of MAPK8 in temozolomide (TMZ) -resistant glioblastoma cells as well as to explore the mechanism of TMZ resistance in glioblastoma cells.

METHODS

Gene Expression Omnibus (GEO) database was used for identifying the differentially expressed genes (DEGs) in TMZ resistant samples. The functional partner genes of TMZ were screened out by Gene-drug interaction network (STITCH) and the glioblastoma-related genes were selected by gene search engine with evidence sentences (Digsee). The interactions among identified DEGs and glioblastoma-related genes were detected by Search Tool for the Retrieval of Interacting Genes (STRING). The dysregulated pathways were identified by Gene set enrichment analysis (GSEA). qRT-PCR was performed to detect the expression level of MAPK8 in glioblastoma cells. Western blot was used to detect the expressions of MAPK8 and MAPK signaling pathway-related proteins. MTT assay was utilized to measure the cell viability of TMZ sensitive and resistant cells. Colony formation assay was performed to detect the clone ability and flow cytometry (FCM) assay was applied to identify the apoptosis rate of TMZ resistant glioblastoma cells.

RESULTS

MAPK8 was one of the DEGs and was up-regulated in TMZ resistant glioblastoma cells. The MAPK signaling pathway was activated in TMZ resistant glioblastoma cells under the condition of over-expression of MAPK8. The inhibition of MAPK8 restrained the colony formation, inducing apoptosis of TMZ resistant glioblastoma cells and suppressed the MAPK signaling pathway.

CONCLUSION

MAPK8 promoted the resistance to TMZ, accelerated cell proliferation and inhibited the apoptosis of glioblastoma cells via activating MAPK signaling pathway.

Mitogen-activated protein kinase eight polymorphisms are associated with immune responsiveness to HBV vaccinations in infants of HBsAg(+)/HBeAg(-) mothers

BACKGROUND

Infants born to hepatitis B surface antigen (HBsAg) positive mothers are at a higher risk for Hepatitis B virus (HBV) infection. Host genetic background plays an important role in determining the strength of immune response to vaccination. We conducted this study to investigate the association between Tumor necrosis factor (TNF) and Mitogen-activated protein kinase eight (MAPK8) polymorphisms and low response to hepatitis B vaccines.

METHODS

A total of 753 infants of HBsAg positive and hepatitis Be antigen (HBeAg) negative mothers from the prevention of mother-to-infant transmission of HBV cohort were included. Five tag single nucleotide polymorphism (SNPs) (rs1799964, rs1800629, rs3093671, rs769177 and rs769178) in TNF and two tag SNPs (rs17780725 and rs3827680) in MAPK8 were genotyped using the MassARRAY platform.

RESULTS

A higher percentage of breastfeeding (P = 0.013) and a higher level of Ab titers were observed in high responders (P < 0.001). The MAPK8 rs17780725 AA genotype increased the risk of low response to hepatitis B vaccines (OR = 3.176, 95% CI: 1.137-8.869). Additionally, subjects with the AA genotype may have a lower Ab titer than subjects with GA or GG genotypes (P = 0.051). Compared to infants who were breastfed, infants who were not breastfed had an increased risk of low response to hepatitis B vaccine (OR = 2.901, 95% CI:1.306-6.441).

CONCLUSIONS

MAPK8 polymorphisms are associated with immune response to HBV vaccinations in infants of HBsAg(+)/HBeAg(-) mothers.

miR-190 protects cardiomyocytes from apoptosis induced by H2O2 through targeting MAPK8 and regulating MAPK8/ERK signal pathway

MicroRNAs (miRs) have been demonstrated to regulate physiological and pathological processes. Numerous miRsprotect against cardiomyocyte injury induced by oxidative stress. However, the function of miR-190 still remains unclear. Here, we determined the expression level of miR-190 in H9c2 cells under H₂O₂ treatment and found that miR-190 expression was significantly inhibited by H₂O₂. Further study indicated that miR-190 significantly reduced cell apoptosisand the LDH and MDA levels of H9c2 cells induced by H₂O₂. Luciferase activity assay, quantitative real-time-PCR, and Western blot demonstrated that miR-190 directly targets MAPK8. Rescue experiment confirmed this hypothesis. Further study has revealed that miR-190 protects H9c2 cells from oxidative stress injury through inhibiting the MAPK8/ERK signal pathway. In conclusion, these data suggest that miR-190 protects against oxidative stress injury of H9c2 cells induced by H₂O₂ through inhibiting MAPK8 expression and the MAPK8/ERK pathway. Our findings provide a potential therapeutic target to promote functional recovery after cardiac ischemia/reperfusion.

MAPK8 regulates chicken male germ cell differentiation through JNK signaling pathway

The study aims to analyze the key signaling pathways in regulating the process of embryonic stem cells (ESCs) differentiation into spermatogonial stem cells (SSCs). We explored the specific regulating mechanisms of C-Jun amino-terminal kinase (JNK) signaling in this process. Interference/overexpression of MAPK8 allows the JNK signaling pathway to be blocked/activated. In Retinoic acid (RA) induced in vitro differentiation assays, the expression of germ cell marker genes, cvh, c-kit, integrin α6 and integrin β1, was observed to upregulate while activating JNK signaling significantly. Fluorescence Activated Cell Sorting (FACs) analysis showed that the proportion of cvh⁺ and integrin α6⁺ cells in the overexpression group was significantly higher than which in the RA + shRNA-MAPK8 group. In in vivo situations, shRNA-MAPK8 could stably express in chicken embryos and significantly down-regulate expression of MAPK8 and downstream genes in JNK signaling pathway. With PAS stain, we found that PGCs (primordial germ cells) was significantly decreased after inhibiting MAPK8. With real-time quantitative PCR (qRT-PCR) and Western Blot, we identified that reproductive related genes expression was significantly suppressed after inhibiting MAPK8 in vivo. We preliminarily concluded that knockdown/ overexpression of MAPK8 could affect differentiation of ESC by inhibiting/activating JNK signal.

SESN2/sestrin 2 induction-mediated autophagy and inhibitory effect of isorhapontigenin (ISO) on human bladder cancers

Isorhapontigenin (ISO) is a new derivative of stilbene isolated from the Chinese herb Gnetum cleistostachyum. Our recent studies have revealed that ISO treatment at doses ranging from 20 to 80 μM triggers apoptosis in multiple human cancer cell lines. In the present study, we evaluated the potential effect of ISO on autophagy induction. We found that ISO treatment at sublethal doses induced autophagy effectively in human bladder cancer cells, which contributed to the inhibition of anchorage-independent growth of cancer cells. In addition, our studies revealed that ISO-mediated autophagy induction occurred in a SESN2 (sestrin 2)-dependent and BECN1 (Beclin 1, autophagy related)-independent manner. Furthermore, we identified that ISO treatment induced SESN2 expression via a MAPK8/JNK1 (mitogen-activated protein kinase 8)/JUN-dependent mechanism, in which ISO triggered MAPK8-dependent JUN activation and facilitated the binding of JUN to a consensus AP-1 binding site in the SESN2 promoter region, thereby led to a significant transcriptional induction of SESN2. Importantly, we found that SESN2 expression was dramatically downregulated or even lost in human bladder cancer tissues as compared to their paired adjacent normal tissues. Collectively, our results demonstrate that ISO treatment induces autophagy and inhibits bladder cancer growth through MAPK8-JUN-dependent transcriptional induction of SESN2, which provides a novel mechanistic insight into understanding the inhibitory effect of ISO on bladder cancers and suggests that ISO might act as a promising preventive and/or therapeutic drug against human bladder cancer.

Tumor necrosis factor-related genes and colon and rectal cancer

Tumor necrosis factor-α (TNF) is a promoter of inflammation. Genes in the TNF pathway include tumor necrosis factor receptor superfamily member 1A (TNFRSF1A), TNF receptor-associated factor 2 (TRAF2), mitogen activated protein kinase 8 (MAPK8), 14 (MAPK14), and mitogen activated protein kinase kinase kinase 7 (MAP3K7), nuclear factor of activated-T-5 (NFAT5) cells and NFAT activated protein with ITAM motif 1 ﹛NFAM1). Data from population-based studies of colon cancer (cases=1,555; controls=1,956) and rectal cancer (cases=754; controls=959) were used. We observed that MAP3K7 rs13208824 was associated with reduced colon cancer risk (OR 0.83, 95% CI 0.71, 0.98 dominant model), TNF rs1800630 was associated with an increased colon cancer risk (OR 1.19 95% CI 1.03, 1.38 for CA/AAvsCC), and TNFRSF1A rs4149570 was associated with reduced risk (OR 0.79 95% CI 0.64, 0.96 TTvsGG). For rectal cancer MAPK8 rs10508901 was associated with increased risk (OR 1.45 95% CI 1.05, 1.99 AA vs CC/CA; NFAT5 (rs12447326 and rs16959025) was associated with a 40% reduced risk for the recessive model. Aspirin/NSAID interacted with MAP3K7 (colon cancer) and with MAPK14, NFAT5, and TRAF2 (rectal cancer); smoking cigarettes interacted with NFAM1 and NFAT2 (colon cancer) and MAPK8, NFAT5, and TNFRSF1A (rectal cancer); BMI interacted with NFAM1 and NFAT5 (colon cancer) and with MAPK8 and TNFRSF1A (rectal cancer). A genotype summary score showed a threefold increased risk of dying with higher mutational load. Although few independent associations were detected, aspirin/NSAID, cigarette smoking, and BMI influenced genes in this pathway. These data suggest pathways through which TNF-signaling operates.