The expression and role of MEKK3 in renal clear cell carcinoma

Clinical Significance and Regulation of ERK5 Expression and Function in Cancer

Extracellular signal-regulated kinase 5 (ERK5) is a unique kinase among MAPKs family members, given its large structure characterized by the presence of a unique C-terminal domain. Despite increasing data demonstrating the relevance of the ERK5 pathway in the growth, survival, and differentiation of normal cells, ERK5 has recently attracted the attention of several research groups given its relevance in inflammatory disorders and cancer. Accumulating evidence reported its role in tumor initiation and progression. In this review, we explore the gene expression profile of ERK5 among cancers correlated with its clinical impact, as well as the prognostic value of ERK5 and pERK5 expression levels in tumors. We also summarize the importance of ERK5 in the maintenance of a cancer stem-like phenotype and explore the major known contributions of ERK5 in the tumor-associated microenvironment. Moreover, although several questions are still open concerning ERK5 molecular regulation, different ERK5 isoforms derived from the alternative splicing process are also described, highlighting the potential clinical relevance of targeting ERK5 pathways.

MEKK3 in hybrid snakehead (Channa maculate ♀ ×Channa argus ♂): Molecular characterization and immune response to infection with Nocardia seriolae and Aeromonas schubertii

Mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 3 (MEKK3) is a serine/threonine protein kinase that acts as a key regulator and is widely involved in various innate and acquired immune signaling pathways. In this study, we first cloned the complete open reading frame (ORF) of the MEKK3 gene (named CcMEKK3) in a hybrid snakehead (Channa maculate ♀ × Channa argus ♂). The full-length ORF of CcMEKK3 is 1851 bp, and encodes a putative protein of 616 amino acids containing a serine/threonine kinase catalytic (S-TKc) domain and a Phox and Bem1p (PB1) domain. A sequence alignment and phylogenetic tree analysis showed that CcMEKK3 is highly conserved relative to the MEKK3 proteins of other teleost species. CcMEKK3 was constitutively expressed in all the healthy hybrid snakehead tissues tested, with greatest expression in the immune tissues, such as the head kidney and spleen. The expression of CcMEKK3 was usually upregulated in the head kidney, spleen, and liver at different time points after infection with Nocardia seriolae or Aeromonas schubertii. Similarly, the dynamic expression levels of CcMEKK3 in head kidney leukocytes after stimulation revealed that CcMEKK3 was induced by LTA, LPS, and poly(I:C). In the subcellular localization analysis, CcMEKK3 was evenly distributed in the cytoplasm of HEK293T cells, and its overexpression significantly promoted the activities of NF-κB and AP-1. These results suggest that CcMEKK3 is involved in the immune defense against these two pathogens, and plays a crucial role in activating the NF-κB and MAPK signaling pathways.

Silencing MEKK3 attenuates cardiomyocyte injury caused by hypoxia/reoxygenation via the sonic hedgehog pathway

MEKK3 is a member of MAP3K, which plays a pivotal role in cardiac diseases. In this study, we aimed to investigate the effects and potential mechanisms of MEKK3 on hypoxia/reoxygenation (H/R) injury of cardiomyocytes. After exposing H9C2 cells to H/R insult, real-time polymerase chain reaction and western blot analysis showed that MEKK3 was highly expressed. Cell viability, cell apoptosis, caspase 3/7 activity, and cleaved-caspase 3 expression were tested using a CCK-8 assay, Cell Death Detection PLUS ELISA, Caspase-Glo 3/7 Assay Kit and western blot analysis, respectively. Mitochondrial membrane potential, cytochrome C expression, adenosine triphosphate (ATP), and reactive oxygen species also were measured using JC-1 staining, western blot analysis, an ATP Assay Kit, and DCFH ₂ -DA staining, respectively. The messenger RNA (mRNA) levels and secretions of TNF-α, IL-6, and IL-1β were evaluated. The results revealed that MEKK3 silencing promoted cell survival and attenuated lactate dehydrogenase leakage, cell apoptosis, caspase 3/7 activity, and the protein level of cleaved-caspase 3. Moreover, knockdown of MEKK3 blocked mitochondrial impairment by inhibiting the loss of mitochondrial membrane potential and cytochrome C expression as well as promoting ATP synthesis. MEKK3 deficiency led to a decrease in reactive oxygen species and malondialdehyde (MDA) generation and an increase in superoxide dismutase (SOD) activity. Deletion of MEKK3 led to reduced inflammatory cytokines in mRNA level and secretion. MEKK3 suppression activated the sonic hedgehog (Shh) signaling pathway in H9C2 cells. After blocking the Shh signaling pathway with a specific inhibitor, cyclopamine, the cardioprotective functions of MEKK3 downregulation were partly abolished. In conclusion, downregulation of MEKK3 prevented apoptosis and inflammation in H9C2 cells via the Shh signaling pathway.

MiR-194 regulates nasopharyngeal carcinoma progression by modulating MAP3K3 expression

Despite the recent development of treatment strategies for nasopharyngeal carcinoma, the effective management of this disease remains a challenging clinical problem. A better understanding of the regulatory roles of miR‐194 and mitogen‐activated protein kinase kinase kinase 3 (MAP3K3) in the nasopharyngeal‐carcinoma‐related gene network is required to address this issue. Here, we measured relative expression of miR‐194 in human nasopharyngeal carcinoma tissues and normal epithelial tissues by quantitative real time PCR. We transfected cultured CNE‐1 and C666‐1 cells with miR‐194 mimics, and then examined the effects on cell proliferation, cell migration and invasion. Luciferase reporter assay was used to validate the putative binding between miR‐194 and MAP3K3. We then examined the effect of knockdown and overexpression of MAP3K3 on cell tumorigenesis. Expression of miR‐194 is significantly down‐regulated in nasopharyngeal carcinoma specimens and tumor cell lines when compared with normal controls. In addition, miR‐194 suppressed tumor cell proliferation and viability, as well as migration and invasion of carcinoma cells. We found that miR‐194 binds the 3′ untranslated region of MAP3K3, and knockdown of miR‐194 inhibited nasopharyngeal carcinoma cell proliferation, migration and invasion. In accordance, overexpression of MAP3K3 reversed the inhibitory effects of miR‐194 in carcinoma cells. This study suggests that expression of miR‐194 is down‐regulated in nasopharyngeal carcinoma, and that miR‐194 can directly target MAP3K3 to regulate tumor progression. Given the pivotal involvement of MAP3K3 in nasopharyngeal carcinoma development, targeting miR‐194 may be a novel strategy for the treatment of nasopharyngeal carcinoma.

Clinicalpathological and prognostic significance of survivin expression in renal cell carcinoma: a meta-analysis

Background

In recent years, survivin expression had been investigated as a prognostic biomarker for renal cell carcinoma (RCC), however, the results were conflicting. This study was aimed to explore the association between survivin expression and clinicalpathological features and the prognostic value for cancer-specific survival (CSS) and overall survival (OS) in RCC.

Results

Eleven studies with 1,697 subjects were included in this meta-analysis. The results showed that survivin expression was associated with higher tumor grade (OR=4.25, 95%CI: 3.04-5.95, p<0.001), advanced tumor stage (OR=3.83, 95%CI: 2.01-7.3, p<0.001) and lymph node metastasis (OR=4.19, 95%CI: 2.34-7.52, p<0.001), but had no association with age, gender or distant metastasis. In addition, survivin expression was also correlated with poor CSS (HR=2.08, 95%CI: 1.07-4.05, p=0.032) and poor OS (HR=2.28, 95%CI: 1.57-3.33, p<0.001).

Materials and Methods

Literature was searched by PubMed, Embase and Web of Science. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were extracted from eligible studies. Fixed or random effects model were used to calculate pooled HRs and 95%CIs according to heterogeneity.

Conclusions

This study demonstrated that survivin expression was associated with more aggressive clinical features and predicted poor CSS and OS in patients with RCC.

Oncogenic signaling of MEK5-ERK5

Mitogen-activated protein kinases (MAPKs) regulate diverse cellular processes including proliferation, cell survival, differentiation, and apoptosis. While conventional MAPK constituents have well-defined roles in oncogenesis, the MEK5 pathway has only recently emerged in cancer research. In this review, we consider the MEK5 signaling cascade, focusing specifically on its involvement in drug resistance and regulation of aggressive cancer phenotypes. Moreover, we explore the role of MEK5/ERK5 in tumorigenesis and metastatic progression, discussing the discrepancies in preclinical studies and assessing its viability as a therapeutic target for anti-cancer agents.

Prognostic and Clinicopathological Significance of Survivin Expression in Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

Previous studies have elevated the prognostic value of survivin in renal cell carcinoma (RCC). To increase statistical power and improve translation, we systematically searched PubMed, Web of Science, and Embase to identify relevant studies until December 2015 and conducted a standard meta-analysis. Based on the inclusion and exclusion criteria, a total of 12 studies, including 2051 patients, were eligible for further analysis. Results showed that high survivin expression in RCC was associated with poor OS (HR = 2.84, 95% CI 1.68-4.79), CSS (HR = 2.36, 95% CI 1.41-3.95), and PFS (HR = 2.20, 95% CI 1.58-3.08). Survivin expression was also correlated with TNM stage (RR = 2.75, 95% CI 2.21-3.44), pathological T stage (RR = 2.19, 95% CI 1.75-2.75), lymph node metastasis (RR = 2.28, 95% CI 1.61-3.25), distant metastasis (RR = 1.56, 95% CI 1.16-2.08), Fuhrman grade (RR = 2.81, 95% CI 2.29-3.45), tumor size (RR = 1.49, 95% CI 1.24-1.78). Our study suggested that survivin was a prognostic marker in RCC. High survivin expression was correlated with poor prognosis and more advanced clinicopathological features, and it could serve as a biomarker for disease management.