Protein phosphorylation affects conformational change, interaction, catalytic activity, and subcellular localization of proteins. Because the post-modification of proteins regulates diverse cellular signaling pathways, the precise control of phosphorylation states is essential for maintaining cellular homeostasis. Kinases function as phosphorylating enzymes, and phosphatases dephosphorylate their target substrates, typically in a much shorter time. The c-Jun N-terminal kinase (JNK) signaling pathway, a mitogen-activated protein kinase pathway, is regulated by a cascade of kinases and in turn regulates other physiological processes, such as cell differentiation, apoptosis, neuronal functions, and embryonic development. However, the activation of the JNK pathway is also implicated in human pathologies such as cancer, neurodegenerative diseases, and inflammatory diseases. Therefore, the proper balance between activation and inactivation of the JNK pathway needs to be tightly regulated. Dual specificity phosphatases (DUSPs) regulate the magnitude and duration of signal transduction of the JNK pathway by dephosphorylating their substrates. In this review, we will discuss the dynamics of phosphorylation/dephosphorylation, the mechanism of JNK pathway regulation by DUSPs, and the new possibilities of targeting DUSPs in JNK-related diseases elucidated in recent studies.

Epithelial–mesenchymal transition (EMT) is generally observed in normal embryogenesis and wound healing. However, this process can occur in cancer cells and lead to metastasis. The contribution of EMT in both development and pathology has been studied widely. This transition requires the up- and down-regulation of specific proteins, both of which are regulated by EMT-inducing transcription factors (EMT-TFs), mainly represented by the families of Snail, Twist, and ZEB proteins. This review highlights the roles of key EMT-TFs and their post-translational regulation in cancer metastasis.

Mikania cordata (Burm. f.) B.L. Rob. has been traditionally used in tropical countries throughout Asia and Africa to treat gastric ulcers, dyspepsia, and dysentery. However, the mechanisms responsible for its anti-inflammatory and antioxidant activities are not fully understood. Therefore, this study sought to investigate the anti-inflammatory and antioxidant effects of methanol extracts of M. cordata (MMC) on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages and elucidate its underlying regulatory mechanism. MMC significantly suppressed the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in LPS-stimulated RAW 264.7 macrophages by downregulating the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels. Moreover, MMC effectively reduced the mRNA expression levels and production of pro-inflammatory cytokines, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α). These suppressive effects of MMC on pro-inflammatory mediators and cytokines were mediated through the inhibition of transforming growth factor beta-activated kinase 1 (TAK1), which subsequently blocked the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). MMC also upregulated the nuclear factor erythroid-2-related factor 2 (Nrf2) by inducing the degradation of Kelch-like ECH-related protein 1 (Keap1), an Nrf2-specific E3 ligase. Accordingly, MMC enhanced Nrf2 target gene expression of anti-oxidative regulators such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). However, it had minimal effect on the DPPH radical scavenging capacity in vitro. Collectively, these findings demonstrate that MMC holds promise as a potential therapeutic agent for alleviating inflammation-related diseases and oxidative stress.

Bischofia javanica (Blume) has been traditionally used to treat inflammatory diseases such as tonsillitis and ulcers throughout Asia, including China, Indonesia, and the Philippines: however, the molecular mechanisms by which B. javanica exerts its antioxidant and anti-inflammatory properties remain largely unknown. In this study, we analyzed the antioxidant and anti-inflammatory mechanisms of methanol extracts of B. javanica leaves (MBJ) in vitro and in vivo. MBJ decreased nitric oxide (NO) production and the expression of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The observed suppression of inflammatory responses by MBJ was correlated with an inhibition of the nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) pathways. Additionally, MBJ induced nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that upregulates the expression of anti-inflammatory and antioxidant genes. Furthermore, MBJ exhibited antioxidant and anti-inflammatory effects in an acute hepatitis mouse model. In conclusion, our results confirm the medicinal properties of B. javanica, and therefore MBJ could be applied to improve inflammatory and redox imbalances in different types of pathologies.

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is a leading cause of cancer-related deaths. As HCC has a high mortality rate and its incidence is increasing worldwide, understanding and treating HCC are crucial for resolving major public health concerns. In the present study, wound healing screening assays were performed using natural product libraries to identify natural chemicals that can inhibit cancer cell migration. Glaucarubinone (GCB) showed a high potential for inhibiting cell migration. The anti-cancer effects of GCB were evaluated using the HCC cell line, Huh7. GCB showed anti-cancer effects, as verified by wound healing, cell migration, invasion, colony formation, and three-dimensional spheroid invasion assays. In addition, cells treated with GCB showed suppressed matrix metalloproteinase activities. Immunoblotting analyses of intracellular signaling pathways revealed that GCB regulated the levels of Twist1, a crucial transcription factor associated with epithelial-to-mesenchymal transition, and mitogen-activated protein kinase. The invasive ability of cancer cells was found to be decreased by the regulation of Twist1 protein levels. Furthermore, GCB downregulated phosphorylation of extracellular signal-regulated kinase. These results indicate that GCB exhibits anti-metastatic properties in Huh7 cells, suggesting that it could be used to treat HCC.

Background: Overexpression of Twist1, one of the epithelial-mesenchymal transition-transcription factors (EMT-TFs), is associated with hepatocellular carcinoma (HCC) metastasis. Pelitinib is known to be an irreversible epidermal growth factor receptor tyrosine kinase inhibitor that is used in clinical trials for colorectal and lung cancers, but the role of pelitinib in cancer metastasis has not been studied. This study aimed to investigate the anti-migration and anti-invasion activities of pelitinib in HCC cell lines.Methods: Using three HCC cell lines (Huh7, Hep3B, and SNU449 cells), the effects of pelitinib on cell cytotoxicity, invasion, and migration were determined by cell viability, wound healing, transwell invasion, and spheroid invasion assays. The activities of MMP-2 and -9 were examined through gelatin zymography. Through immunoblotting analyses, the expression levels of EMT-TFs (Snail1, Twist1, and ZEB1) and EMT-related signaling pathways such as mitogen-activated protein kinases (MAPKs) and Akt signaling pathways were measured. The activity and expression levels of target genes were analyzed by reporter assay, RT-PCR, quantitative RT-PCR, and immunoblotting analysis. Statistical analysis was performed using one-way ANOVA with Dunnett's Multiple comparison tests in Prism 3.0 to assess differences between experimental conditions.Results: In this study, pelitinib treatment significantly inhibited wound closure in various HCC cell lines, including Huh7, Hep3B, and SNU449. Additionally, pelitinib was found to inhibit multicellular cancer spheroid invasion and metalloprotease activities in Huh7 cells. Further investigation revealed that pelitinib treatment inhibited the migration and invasion of Huh7 cells by inducing Twist1 degradation through the inhibition of MAPK and Akt signaling pathways. We also confirmed that the inhibition of cell motility by Twist1 siRNA was similar to that observed in pelitinib-treated group. Furthermore, pelitinib treatment regulated the expression of target genes associated with EMT, as demonstrated by the upregulation of E-cadherin and downregulation of N-cadherin.Conclusion: Based on our novel finding of pelitinib from the perspective of EMT, pelitinib has the ability to inhibit EMT activity of HCC cells via inhibition of Twist1, and this may be the potential mechanism of pelitinib on the suppression of migration and invasion of HCC cells. Therefore, pelitinib could be developed as a potential anti-cancer drug for HCC.