TGF-β1 induced fascin1 expression facilitates the migration and invasion of kidney carcinoma cells through ERK and JNK signaling pathways

Farnesoid X receptor modulator 12β-(m-methyl-benzoyl)-11,12-dihydro oleanolic acid represses liver fibrosis by inhibiting ERK/p38 signaling pathways

Liver fibrosis is a common pathological process in the progression of several chronic liver diseases to cirrhosis and hepatocellular carcinoma. Therefore, the development of medications that can repress the progress of liver fibrosis is essential. We discovered that initially, 12β-(m-methyl-benzoyl)-11,12-dihydro oleanolic acid (12d-OA), a farnesoid X receptor (FXR) modulator, possessed potential anti-fibrotic properties. Through an in-depth study, we revealed that 12d-OA not only inhibited the expression of fibrogenic markers in the LX-2 cells and HSC-T6 cells but also exhibited significant protective effects against liver injury and liver fibrosis in bile duct ligation (BDL) rats. Further exploration of its molecular mechanism indicated that 12d-OA exerted antifibrotic activity by inhibiting the extracellular signal-regulated kinase (ERK)/stress-activated protein kinase (p38) signaling pathways. Consequently, the great effects of 12d-OA in vitro and in vivo suggest that it may be a good candidate for liver fibrosis.

The involvement of PDIA2 gene in the progression of renal cell carcinoma is potentially through regulation of JNK signaling pathway

Renal cell carcinoma (RCC) with poor prognosis and high incidence rate is a common malignant disease. Current therapies could bring little benefit for the patients with advanced-stage RCC. PDIA2 is an isomerase responsible for protein folding and its role in cancer including RCC is under investigation. In this study, we found that PDIA2 was expressed much higher in RCC tissues than the control but the methylation level of PDIA2 promoter was lower based on the TCGA data. Patients with higher PDIA2 expression exerted worse survival. In clinical specimen, PDIA2 expression was correlated to patients' clinical factors such as TNM stage (I/II vs III/IV, p = 0.025) and tumor size (≤ 7 cm vs > 7 cm, p = 0.004). Moreover, K-M analysis showed that PDIA2 was associated with patients' survival in RCC. PDIA2 was expressed much higher in cancer cells A498 than 786-O than that in 293 T cells. After PDIA2 was knocked down, cell proliferation, migration and invasion was potently inhibited. But cell apoptotic rate increased reversely. Furthermore, the efficacy of Sunitinib on RCC cells was strengthened after PDIA2 knockdown. In addition, knockdown of PDIA2 gene leaded to downregulation of levels of JNK1/2, phosphorylated JNK1/2, c-JUN, and Stat3. But this inhibition was partially released when JNK1/2 was overexpressed. In consistent, cell proliferation was also partially recovered. In summary, PDIA2 plays important role in progression of RCC and JNK signaling pathway might be regulated by PDIA2. This study suggests PDIA2 as a candidate target for therapy of RCC.

Lactoferrin alleviates cyclophosphamide induced-nephropathy through suppressing the orchestration between Wnt4/β-catenin and ERK1/2/NF-κB signaling and modulating klotho and Nrf2/HO-1 pathway

AIMS

Cyclophosphamide is an alkylating agent with vast arrays of therapeutic activity. Currently, its medical use is limited due to its numerous adverse events, including nephrotoxicity. This study aimed to follow the molecular mechanisms behind the potential renoprotective action of lactoferrin (LF) against cyclophosphamide (CP)-induced renal injury.

MATERIALS AND METHODS

For fulfillment of our aim, Spragw-Dwaly rats were orally administrated LF (300 mg/kg) for seven consecutive days, followed by a single intraperitoneal injection of CP (150 mg/kg).

KEY FINDINGS

Treatment of CP-injured rats with LF significantly reduced the elevated creatinine and blood urea nitrogen (BUN), markedly upregulated Nrf2/HO-1 signaling with consequent increase in renal total antioxidant capacity (TAC) and decrease in renal malondialdehyde (MDA) level. Furthermore, LF treatment significantly reduced the elevated renal p-ERK1/2 expression, tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB) levels in CP-treated animals. Interestingly, LF treatment downregulated Wnt4/β-catenin signaling and increased both renal klotho gene expression and serum klotho level. Furthermore, LF treatment reduced apoptosis in kidney tissue via suppressing GSK-3β expression and modulating caspase-3 and Bcl2 levels. Histopathological examination of kidney tissue confirmed the protective effect of LF against CP-induced renal injury.

SIGNIFICANCE

The present findings document the renoprotective effect of LF against CP-induced nephropathy, which may be mediated via suppressing ERK1/2/ NF-κB and Wnt4/β-catenin trajectories and enhancing klotho expression and Nrf2/HO-1 signaling.

The Role of Fascin-1 in Human Urologic Cancers: A Promising Biomarker or Therapeutic Target?

Human cancer statistics show that an increased incidence of urologic cancers such as bladder cancer, prostate cancer, and renal cell carcinoma. Due to the lack of early markers and effective therapeutic targets, their prognosis is poor. Fascin-1 is an actin-binding protein, which functions in the formation of cell protrusions by cross-linking with actin filaments. Studies have found that fascin-1 expression is elevated in most human cancers and is related to outcomes such as neoplasm metastasis, reduced survival, and increased aggressiveness. Fascin-1 has been considered as a potential therapeutic target for urologic cancers, but there is no comprehensive review to evaluate these studies. This review aimed to provide an enhanced literature review, outline, and summarize the mechanism of fascin-1 in urologic cancers and discuss the therapeutic potential of fascin-1 and the possibility of its use as a potential marker. We also focused on the correlation between the overexpression of fascin-1 and clinicopathological parameters. Mechanistically, fascin-1 is regulated by several regulators and signaling pathways (such as long noncoding RNA, microRNA, c-Jun N-terminal kinase, and extracellular regulated protein kinases). The overexpression of fascin-1 is related to clinicopathologic parameters such as pathological stage, bone or lymph node metastasis, and reduced disease-free survival. Several fascin-1 inhibitors (G2, NP-G2-044) have been evaluated in vitro and in preclinical models. The study proved the promising potential of fascin-1 as a newly developing biomarker and a potential therapeutic target that needs further investigation. The data also highlight the inadequacy of fascin-1 to serve as a novel biomarker for prostate cancer.

The post-translational modification of Fascin: impact on cell biology and its associations with inhibiting tumor metastasis

The post-translational modifications (PTMs), which are crucial in the regulation of protein functions, have great potential as biomarkers of cancer status. Fascin (Fascin actin-bundling protein 1, FSCN1), a key protein in the formation of filopodia that is structurally based on actin filaments (F-actin), is significantly associated with tumor invasion and metastasis. Studies have revealed various regulatory mechanisms of human Fascin, including PTMs. Although a number of Fascin PTM sites have been identified, their exact functions and clinical significance are much less explored. This review explores studies on the functions of Fascin and briefly discusses the regulatory mechanisms of Fascin. Next, to review the role of Fascin PTMs in cell biology and their associations with metastatic disease, we discuss the advances in the characterization of Fascin PTMs, including phosphorylation, ubiquitination, sumoylation, and acetylation, and the main regulatory mechanisms are discussed. Fascin PTMs may be potential targets for therapy for metastatic disease.

GLUT3 Promotes Epithelial–Mesenchymal Transition via TGF-β/JNK/ATF2 Signaling Pathway in Colorectal Cancer Cells

Glucose transporter (GLUT) 3, a member of the GLUTs family, is involved in cellular glucose utilization and the first step in glycolysis. GLUT3 is highly expressed in colorectal cancer (CRC) and it leads to poor prognosis to CRC patient outcome. However, the molecular mechanisms of GLUT3 on the epithelial–mesenchymal transition (EMT) process in metastatic CRC is not yet clear. Here, we identified that activation of the c-Jun N-terminal kinase (JNK)/activating transcription factor-2 (ATF2) signaling pathway by transforming growth factor-β (TGF-β) promotes GLUT3-induced EMT in CRC cells. The regulation of GLUT3 expression was significantly associated with EMT-related markers such as E-cadherin, α- smooth muscle actin (α-SMA), plasminogen activator inhibitor-1 (PAI-1), vimentin and zinc finger E-box binding homeobox 1 (ZEB1). We also found that GLUT3 accelerated the invasive ability of CRC cells. Mechanistically, TGF-β induced the expression of GLUT3 through the phosphorylation of JNK/ATF2, one of the SMAD-independent pathways. TGF-β induced the expression of GLUT3 by increasing the phosphorylation of JNK, the nuclear translocation of the ATF2 transcription factor, and the binding of ATF2 to the promoter region of GLUT3, which increased EMT in CRC cells. Collectively, our results provide a new comprehensive mechanism that GLUT3 promotes EMT process through the TGF-β/JNK/ATF2 signaling pathway, which could be a potential target for the treatment of metastatic CRC.

STAT3/HIF-1α/fascin-1 axis promotes RA FLSs migration and invasion ability under hypoxia

Rheumatoid arthritis (RA) synovium was identified as "tumor-like" tissues because of the hypoxic microenvironment, significant cell proliferation, and invasion phenotypes. It was reported that hypoxia promoted tumor aggressiveness via up-regulated expression of fascin-1 in cancer. However, the role of fascin-1 in RA synovial hyperplasia and joint injury progression remains unknown. In the current study, we first identified that both fascin-1 and HIF-1α were highly expressed in the RA synovium, in which they were widely colocalized, compared to osteoarthritis(OA). As well, levels of fascin-1 in RA fibroblast-like synoviocytes(FLSs) were found significantly higher than those in OA FLSs. Further, it was demonstrated that the mRNA and protein levels of fascin-1 in RA FLSs were up-regulated in hypoxia (3 % O₂) and experimental hypoxia induced by cobalt chloride. Mechanistically, the HIF-1α-mediated hypoxia environment activated the gene expression of the fascin-1 protein, which in turn promoted the migration and invasion of RA FLSs. Accordingly, the restoration of FLSs migration and invasion was observed following siRNA-mediated silencing of fascin-1 and HIF-1α expression. Notably, under the experimental hypoxia, we found that the expression levels of fascin-1, HIF-1α, and p-STAT3 were increased in a time-dependent manner, and fascin-1and HIF-1α expressions were dependent on p-STAT3. Our results indicated that hypoxia-induced fascin-1 up-regulation promoted RA FLSs migration and invasion through the STAT3/HIF-1α/fascin-1 axis, which might represent a novel therapeutic target for the treatment of RA.

Endoplasmic reticulum unfolded protein response modulates the adaptation of Trachemys scripta elegans in salinity water

Trachemys scripta elegans, as a freshwater invasive species, can survive and lay eggs in brackish water, which may lead to the expansion of its potential invasion range due to freshwater salinization. Our previous studies have shown that high salinity leads to the accumulation of serum lipid content, which may induce endoplasmic reticulum stress (ERS) in the turtle. To better understand whether ERS is triggered by salinity, and in turn whether the turtles promote the protection mechanism, we exposed the turtles to the freshwater (CK), 5‰ salinity water (S5) and 15‰ salinity water (S15), and sampled at 6 h, 24 h and 30 d. 13 differentially expressed genes (DEGs) related to ERS pathways were found in the comparison of CK vs. S15 by transcriptomics analysis. Then, the mRNA and protein expression of ERS and its related activation pathways were further investigated. ERS marker glucose regulated protein 78 kD (GRP78) increased significantly (p < 0.05) in both the transcript and protein levels after exposure to 15‰ salinity water, which clearly indicated that salinity could induce ERS in T. s. elegans. Meanwhile, the three unfolded protein response (UPR) including transducers protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α) and activating transcription factor-6 (ATF6) were promoted by salinity, suggesting that the turtle might promote physiological process to eliminate damaged cells and cope with unfolded proteins accumulation induced by ERS. Our results provide new insight into the mechanism of salinity adaptation in T. s. elegans and salt-tolerant biological invasion.

The role of microRNAs in epithelial to mesenchymal transition and cancers; focusing on mir-200 family

Epithelial to mesenchymal transition (EMT) is a process associated with cancer malignancy and metastases. Cells undergoing EMT lose their epithelial phenotype and acquire mesenchymal phenotype. This process is accompanied by several molecular changes such as decrease of E-cadherin and increase of N-cadherin which is called the "cadherin swich". MicroRNAs (miRNAs, miRs) are small non-coding RNAs having ability to regulate genes post-transcriptionally. Nowadays they are believed to take part in multiple physiological and pathological processes including cancer development. Comparison between TargetScan7 (www.targetscan.org) results for miR-200b and metanalysis of genes involved in EMT showed that miR-200b has a potential binding site in 60 genes that are involved in EMT (the majority of them were associated with mesenchymal phenotype). Our review summarizes literature findings contributing to experimentally proven interactions between miR-200b and genes involved in EMT process including cell receptors, signaling pathways, cell cycle or cell adhesion. The results of those interactions indicate that miR-200b may have an inhibitory impact on EMT or even in selected cases is able to restore epithelial phenotype.

Fascin actin-bundling protein 1 in human cancer: promising biomarker or therapeutic target?

Fascin actin-bundling protein 1 (FSCN1) is a highly conserved actin-bundling protein that cross links F-actin microfilaments into tight, parallel bundles. Elevated FSCN1 levels have been reported in many types of human cancers and have been correlated with aggressive clinical progression, poor prognosis, and survival outcomes. The overexpression of FSCN1 in cancer cells has been associated with tumor growth, migration, invasion, and metastasis. Currently, FSCN1 is recognized as a candidate biomarker for multiple cancer types and as a potential therapeutic target. The aim of this study was to provide a brief overview of the FSCN1 gene and protein structure and elucidate on its actin-bundling activity and physiological functions. The main focus was on the role of FSCN1 and its upregulatory mechanisms and significance in cancer cells. Up-to-date studies on FSCN1 as a novel biomarker and therapeutic target for human cancers are reviewed. It is shown that FSCN1 is an unusual biomarker and a potential therapeutic target for cancer.

RNF2 Mediates Hepatic Stellate Cells Activation by Regulating ERK/p38 Signaling Pathway in LX-2 Cells

The therapeutic approach of liver fibrosis is still an unsolved clinical problem worldwide. Notably, the accumulation of extracellular matrix (ECM) in the liver is mediated by the production of cytokines and growth factors, such as transforming growth factor-β1 (TGF-β1) in hepatic stellate cells (HSCs). Ring finger protein 2 (RNF2) was identified as the catalytic subunit of polycomb repressive complex 1 (PRC1), mediating the monoubiquitination of histone H2A. In recent years, a growing amount of evidence suggests that RNF2 may play an important role in multiple pathological processes involved in cancer. Here, we explored the role of RNF2 in liver fibrogenesis and its potential mechanisms. The results showed that RNF2 was up-regulated in human fibrotic liver tissue. Knockdown of RNF2 led to a decreasing expression of collagen1 and α-smooth muscle actin (α-SMA) in LX-2 cells, which was upregulated by RNF2 overexpression. Moreover, RNF2 overexpression significantly promoted TGF-β1-induced LX-2 cell proliferation but decreased apoptosis. Furthermore, knockdown of RNF2 inhibited the activation of ERK/p38 signaling pathways induced by TGF-β1. These data suggested that RNF2 is an effective pro-fibrogenic factor for HSC activation via ERK/p38 signaling pathway. RNF2 inhibition might be a promising therapeutic target for liver fibrosis.

MicroRNA‑145‑5p suppresses fascin to inhibit the invasion and migration of cervical carcinoma cells

MicroRNAs (miRs) can affect the progression of cervical cancer (CC). The present study investigated the function of miR-145-5p in CC and demonstrated its association with fascin (FSCN1). The expression levels of miR-145-5p in CC tissues and cell lines were analyzed using reverse transcription-quantitative PCR, and its direct targets were explored using a luciferase reporter assay. The viability, migration and invasion of HeLa cells transfected with small interfering FSCN1 or with miR-145-5p mimics and inhibitors were analyzed using Cell Counting Kit-8 and Transwell assays. The expression levels of FSCN1 mRNA and protein were investigated using reverse transcription PCR and western blotting. miR-145-5p was downregulated in CC tissues and cell lines. Moreover, overexpression of miR-145-5p inhibited the migration, invasion and viability of HeLa cells. miR-145-5p directly targeted FSCN1, which regulated the suppressive functions of miR-145-5p in CC cells. Overall, miR-145-5p is a tumor suppressor gene and a promising target for CC treatment.

How does fascin promote cancer metastasis?

Fascin is an F-actin-bundling protein that cross-links individual actin filaments into straight and stiff bundles. Fascin overexpression in cancer is strongly associated with poor prognosis and metastatic progression across different cancer types. It is well established that fascin plays a causative role in promoting metastatic progression. We will review the recent progress in our understanding of mechanisms underlying fascin-mediated cancer metastasis. This review will cover the biochemical basis for fascin-bundling activity, the mechanisms by which cancer cells upregulate fascin expression and the mechanism underlying fascin-mediated cancer cell migration, invasion, and metastatic colonization. We propose that fascin has broad roles in both metastatic dissemination and metastatic colonization. Understanding these mechanisms will be crucial to the development of anti-metastasis therapeutics targeting fascin.

Tumor Suppressive Function of NQO1 in Cutaneous Squamous Cell Carcinoma (SCC) Cells

Cutaneous squamous cell carcinoma (SCC) is a common cancer that significantly decreases the quality of life. It is known that external stimulus such as ultraviolet (UV) radiation induces cutaneous SCC via provoking oxidative stress. NAD(P)H dehydrogenase 1 (NQO1) is a ubiquitous flavoenzyme that functions as a guardian against oxidative stress. However, the effect of NQO1 on cutaneous SCC is not clearly elucidated. In this study, we investigated the effect of NQO1 on cutaneous SCC cells using the recombinant adenoviruses that can upregulate and/or downregulate NQO1 expression. Overexpression of NQO1 resulted in significant decrease of cell proliferation and colony forming activity of SCC lines (SCC12 and SCC13 cells). By contrast, knockdown of NQO1 increased the cell proliferation and colony forming activity. Accordingly, the levels of proliferation-related regulators, such as Cyclin D1, Cyclin E, PCNA, SOX2, and p63, were decreased by the overexpression of NQO1, while those were increased by knockdown of NQO1. In addition, NQO1 affected the invasion and migration of SCC cells in a very similar way, with the regulation of epithelial-mesenchymal transition- (EMT-) related molecules, including E-cadherin, N-cadherin, Vimentin, Snail, and Slug. Finally, the overexpression of NQO1 decreased the level of phosphorylated AKT, JNK, and p38 MAPK, while the knockdown of NQO1 increased the level of phosphorylated signaling molecules. Based on these data, NQO1 has tumor suppressive function in cutaneous SCC cells.

Heat shock transcription factor 1 affects kidney tubular cell migration by regulating the TGF‑β1‑Smad2/3 signaling pathway

Cell migration is important for renal recovery from tubular cell injury. Heat shock transcription factor 1 (HSF1) is a well‑studied regulatory factor that is active during acute kidney injury. HSF1 is also involved in the migration process during tumor metastasis. Therefore, we hypothesized that HSF1 may promote the recovery of renal function by affecting kidney tubular cell migration. A wound healing assay was used to examine the cell migration rate. The results demonstrated that the migration of rat kidney proximal tubular cells (RPTCs) was increased following knockdown of HSF1. In addition, the invasion ability of HSF1 knockdown RPTCs was also significantly upregulated. The present study also identified that transforming growth factor‑β1 (TGF‑β1) was highly expressed at the edge of the wound in control cells, and its expression was further increased upon knockdown of HSF1. Inhibition of TGF‑β1 signaling prevented RPTC HSF1 knockdown cell migration, suggesting that HSF1‑regulated RPTC cell migration was dependent on the TGF‑β1 signaling pathway. Furthermore, phosphorylation of TGF‑β1 and Smad2/3 was induced in HSF1 knockdown cells. Together, these results suggest that HSF1 may suppress RPTC migration by inhibiting the activation of the TGF‑β1‑Smad2/3 signaling pathway.

Inhibition of LONP1 Suppresses Pancreatic Cancer Progression Via c-Jun N-Terminal Kinase Pathway-Meditated Epithelial-Mesenchymal Transition

OBJECTIVE

The aim of this study was to investigate the role of LONP1 in the progression of pancreatic cancer.

METHODS

Lentivirus was used to silence LONP1 in PANC-1 cells. Colony formation assay, cell counting kit (CCK8) assay, cell scratch-wound assay, and transwell assay were used to assess the effects of our strategy on inhibiting cancer growth, migration, and invasion. Protein expression was detected by Western blot analysis.

RESULTS

The expression of LONP1 in pancreatic carcinoma tissues was higher than that in adjacent normal pancreatic tissues. Downregulation of LONP1 suppressed the proliferation, migration, and invasion of PANC-1 cells. Knockdown of LONP1 in PANC-1 cells inhibited epithelial-mesenchymal transition and matrix metalloprotein (MMP) 2/9 by downregulation of vimentin, snail, slug, MMP2, and MMP9 and upregulation of claudin-1. The c-Jun N-terminal kinase pathway was inactivated in LONP1 knockdown PANC-1 cells. Activation of the c-Jun N-terminal kinase pathway by anisomycin treatment significantly reversed the changes in epithelial-mesenchymal transition markers and MMP2/9 induced by ablation of LONP1 in PANC-1 cells.

CONCLUSIONS

LONP1 plays a vital role in the proliferation and metastasis of pancreatic cancer, which provides a potential therapeutic target for the treatment of pancreatic cancer.

Long non-coding RNA ZEB1-AS1 regulates miR-200b/FSCN1 signaling and enhances migration and invasion induced by TGF-β1 in bladder cancer cells

Background

The effect of competing endogenous RNA (ceRNA) can regulate gene expression by competitively binding microRNAs. Fascin-1 (FSCN1) plays an important role in the regulation of cellular migration and invasion during tumor progression, but how its regulatory mechanism works through the ceRNA effect is still unclear in bladder cancer (BLCA).

Methods

The role of fascin-1, miR-200b, and ZEB1-AS1 in BLCA was investigated in vitro and in vivo. The interaction between fascin-1, miR-200b, and ZEB1-AS1 was identified using bioinformatics analysis, luciferase activity assays, RNA-binding protein immunoprecipitation (RIP), quantitative PCR, and western blotting. Loss (or gain)-of-function experiments were performed to investigate the biological roles of miR-200b and ZEB1-AS1 on migration, invasion, proliferation, cell apoptosis, and cell cycle.

Results

ZEB1-AS1 functions as a competing endogenous RNA in BLCA to regulate the expression of fascin-1 through miR-200b. Moreover, the oncogenic long non-coding RNA ZEB1-AS1 was highly expressed in BLCA and positively correlated with high tumor grade, high TNM stage, and reduced survival of patients with BLCA. Moreover, ZEB1-AS1 downregulated the expression of miR-200b, promoted migration, invasion, and proliferation, and inhibited apoptosis in BLCA. Furthermore, we found TGF-β1 induced migration and invasion in BLCA by regulating the ZEB1-AS1/miR-200b/FSCN1 axis.

Conclusion

The observations in this study identify an important regulatory mechanism of fascin-1 in BLCA, and the TGF-β1/ZEB1-AS1/miR-200b/FSCN1 axis may serve as a potential target for cancer therapeutic purposes.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1102-6) contains supplementary material, which is available to authorized users.

Blockade of ERK1/2 by U0126 alleviates uric acid-induced EMT and tubular cell injury in rats with hyperuricemic nephropathy

Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are serine/threonine kinases and function as regulators of cellular proliferation and differentiation. Recently, we demonstrated that inhibition of ERK1/2 alleviates the development and progression of hyperuricemia nephropathy (HN). However, its potential roles in uric acid-induced tubular epithelial-mesenchymal transition (EMT) and tubular epithelial cell injury are unknown. In this study, we showed that hyperuricemic injury induced EMT as characterized by downregulation of E-cadherin and upregulation of vimentin and Snail1 in a rat model of HN. This was coincident with epithelial cells arrested at the G₂/M phase of cell cycle, activation of Notch1/Jagged-1 and Wnt/β-catenin signaling pathways, and upregulation of matrix metalloproteinase-2 (MMP-2) and MMP-9. Administration of U0126, a selective inhibitor of ERK1/2, blocked all these responses. U0126 was also effective in inhibiting renal tubular cell injury, as shown by decreased expression of lipocalin-2 and kidney injury molecule-1 and active forms of caspase-3. U0126 or ERK1/2 siRNA can inhibit tubular cell EMT and cell apoptosis as characterized with decreased expression of cleaved caspase-3. Moreover, ERK1/2 inhibition suppressed hyperuricemic injury-induced oxidative stress as indicated by decreased malondialdehyde and increased superoxide dismutase. Collectively, ERK1/2 inhibition-elicited renal protection is associated with inhibition of EMT through inactivation of multiple signaling pathways and matrix metalloproteinases, as well as attenuation of renal tubule injury by enhancing cellular resistance to oxidative stress.

Blockade of enhancer of zeste homolog 2 alleviates renal injury associated with hyperuricemia

Hyperuricemia has been identified as an independent risk factor for chronic kidney disease (CKD) and is associated with the progression of kidney diseases. It remains unknown whether enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 methyltransferase, can regulate metabolism of serum uric acid and progression of renal injury induced by hyperuricemia. In this study, we demonstrated that blockade of EZH2 with 3-DZNeP, a selective EZH2 inhibitor, or silencing of EZH2 with siRNA inhibited uric acid-induced renal fibroblast activation and phosphorylation of Smad3, epidermal growth factor receptor (EGFR), and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in cultured renal fibroblasts. Inhibition of EZH2 also suppressed proliferation of renal fibroblasts and epithelial-mesenchymal transition of tubular cells. In a mouse model of renal injury induced by hyperuricemia, EZH2 and trimethylation of histone H3 at lysine27 expression levels were enhanced, which was coincident with renal damage and increased expression of lipocalin-2 and cleaved caspase-3. Inhibition of EZH2 with 3-DZNeP blocked all these responses. Furthermore, 3-DZNeP treatment decreased the level of serum uric acid and xanthine oxidase activity, alleviated renal interstitial fibrosis, inhibited activation of transforming growth factor-β/Smad3, EGFR/ERK1/2, and nuclear factor-κB signaling pathways, as well as reduced expression of multiple chemokines/cytokines. Collectively, EZH2 inhibition can reduce the level of serum uric acid and alleviate renal injury and fibrosis through a mechanism associated with inhibition of multiple signaling pathways. Targeting EZH2 may be a novel strategy for the treatment of hyperuricemia-induced CKD.