Mitogen-activated protein kinase (MAPK) cascades are key signalling pathways that regulate a wide variety of cellular processes, including proliferation, differentiation, apoptosis and stress responses. The MAPK pathway includes three main kinases, MAPK kinase kinase, MAPK kinase and MAPK, which activate and phosphorylate downstream proteins. The extracellular signal-regulated kinases ERK1 and ERK2 are evolutionarily conserved, ubiquitous serine-threonine kinases that regulate cellular signalling under both normal and pathological conditions. ERK expression is critical for development and their hyperactivation plays a major role in cancer development and progression. The Ras/Raf/MAPK (MEK)/ERK pathway is the most important signalling cascade among all MAPK signal transduction pathways, and plays a crucial role in the survival and development of tumour cells. The present review discusses recent studies on Ras and ERK pathway members. With respect to processes downstream of ERK activation, the role of ERK in tumour proliferation, invasion and metastasis is highlighted, and the role of the ERK/MAPK signalling pathway in tumour extracellular matrix degradation and tumour angiogenesis is emphasised. signalling elements that regulate basic processes including cell proliferation, differentiation and stress responses (1-3). These cascades transmit signals through sequential activation of three to five layers of protein kinases known as MAPK kinase kinase kinase (MAP4K), MAPK kinase kinase (MAP3K), MAPK kinase (MAPKK), MAPK and MAPK-activated protein kinases (MAPKAPK). The first three central layers are considered as a basic core unit, while the last two layers appear in some cascades and can vary among cells and stimuli. Four MAPK cascades have been defined based on the components in the MAPK layer: ERK1/2, c-Jun N-terminal kinase (JNK), p38 MAPK and ERK5. This review focuses on the ERK cascade (4-6) which involves several kinases in the MAP3K layer (mainly Rafs), including Ras/Raf/MAPK (MEK) 1/2 at the MAPKK layer, ERK1/2 at the MAPK layer and several MAPKAPKs in the next layer (ribosomal s6 kinases, MAP kinase-interacting serine/threonine-protein kinases, mitogen-and stress-activated protein kinases and cytosolic phospholipase A2). ERK cascades are highly regulated cascades that are responsible for basic cellular processes, including cell proliferation and differentiation. These regulatory factors affect bispecific phosphatases (7-10), scaffold proteins (11-14), signal duration and intensity (15), and the dynamic subcellular localization of cascade components (16,17). Due to the importance of the ERK cascade, ERK disorders are harmful to cells and ultimately to the body. Excessive activation of upstream proteins and kinases in the ERK pathway has been shown to induce various diseases, including cancer, inflammation, developmental disorders and neurological disorders (18-22). Since ERK1 and ERK2 are very similar, the singular form of ERK is used in this review, although two subtypes exist. Dysfunction in the Ras-ERK pat...

No abstract

BackgroundSinomenine (SIN) is an extract of the Chinese medicinal herb Sinomenium acutum; it has various pharmacological properties, including immunosuppression and anti-inflammation. The present study aimed to investigate whether SIN has an anti-depressant-like effect in a mouse model of depression induced by chronic unpredictable mild stress (CUMS), and to explore the underlying molecular mechanisms.Material/MethodsA mouse model of depression was established and treated with different concentrations of SIN (30, 100, or 300 mg/kg). Then, behavioral tests, including sucrose preference test (SPT), forced swimming test (FST), and the tail suspension test (TST), were performed. The levels of norepinephrine (NE), 5-hydroxytryptamine (5-HT), and proinflammatory cytokines (interleukin-1β [IL-1β] interleukin-6 [IL-6], and tumor necrosis factor-α [TNF-α]) in the hippocampus of mice were detected by ELISA assay. The levels of p-p38, p-p65, NLRP3, ASC, and caspase-1 were measured by Western blot or/and qRT-PCR.ResultsThe results showed that SIN significantly relieved CUMSinduced depressive-like behaviors. Compared with the model mice, SIN treatment significantly increased the sucrose preference of the mice, and the immobility time in the forced swimming and the tail suspension test were shortened. In addition, SIN decreased CUMS-induced reduction in the concentrations of NE and 5-HT in the hippocampus of mice. SIN reduced CUMS-induced increases in the levels of IL-1β, IL-6, and TNF-α in the hippocampus of mice. Furthermore, activation of the p38MAPK-NF-κB pathway and the nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome induced by CUMS were inhibited by SIN treatment.ConclusionsIn conclusion, our results indicate the antidepressantlike effects of SIN on chronic unpredictable mild stress-induced depression in a mouse model.

No abstract

Background/Aims: Several factors influencing postoperative pain and the effect of opioid analgesics have been investigated on an individual level. The aim of this study was to clarify the impact of catecholamine-O-methyltransferase (COMT) gene Val158Met on opioid consumption in postoperative patients. Methods: A systematic review and meta-analysis of the literature up to September 30, 2017, were performed by using PubMed, Cochrane Library, ISI Web of Science, and Chinese National Knowledge Infrastructure (CNKI) database. The meta-analysis examined all studies involving the association between genetic polymorphisms of COMT Val158Met and opioid consumption during the acute postoperative period. Results: Of the 153 identified studies, 23 studies were retrieved for systematic review and 10 studies were retrieved for meta-analysis. However, it was impossible to conduct metaanalysis on the association between COMT Val158Met polymorphism and postoperative pain because of heterogeneity of the data. Overall, meta-analysis showed that COMT Val/ Met carriers consumed less opioid for analgesia within the first 24 hours after surgery (SMD = 0.14, 95% CI = [0.03, 0.25], P = 0.01) but not within 48 hours (SMD = 0.14, 95% CI = [0.08, 0.36], P = 0.21). There was no significant difference in opioid consumption between Val/ Val and Met/Met patients. Conclusion: Patients with Val/Met but not Met/Met allele variant consumed less opioid, though larger and better-designed studies are required to obtain an exclusive conclusion about the correlation between postoperative pain and COMT Val158Met polymorphism.