The JNK inhibitor SP600129 enhances apoptosis of HCC cells induced by the tumor suppressor WWOX

Zfra Inhibits the TRAPPC6AΔ-Initiated Pathway of Neurodegeneration

When WWOX is downregulated in middle age, aggregation of a protein cascade, including TRAPPC6AΔ (TPC6AΔ), TIAF1, and SH3GLB2, may start to occur, and the event lasts more than 30 years, which results in amyloid precursor protein (APP) degradation, amyloid beta (Aβ) generation, and neurodegeneration, as shown in Alzheimer's disease (AD). Here, by treating neuroblastoma SK-N-SH cells with neurotoxin MPP+, upregulation and aggregation of TPC6AΔ, along with aggregation of TIAF1, SH3GLB2, Aβ, and tau, occurred. MPP+ is an inducer of Parkinson's disease (PD), suggesting that TPC6AΔ is a common initiator for AD and PD pathogenesis. Zfra, a 31-amino-acid zinc finger-like WWOX-binding protein, is known to restore memory deficits in 9-month-old triple-transgenic (3xTg) mice by blocking the aggregation of TPC6AΔ, SH3GLB2, tau, and amyloid β, as well as inflammatory NF-κB activation. The Zfra4-10 peptide exerted a strong potency in preventing memory loss during the aging of 3-month-old 3xTg mice up to 9 months, as determined by a novel object recognition task (ORT) and Morris water maize analysis. Compared to age-matched wild type mice, 11-month-old Wwox heterozygous mice exhibited memory loss, and this correlates with pT12-WWOX aggregation in the cortex. Together, aggregation of pT12-WWOX may link to TPC6AΔ aggregation for AD progression, with TPC6AΔ aggregation being a common initiator for AD and PD progression.

WWOX and Its Binding Proteins in Neurodegeneration

WW domain-containing oxidoreductase (WWOX) is known as one of the risk factors for Alzheimer's disease (AD), a neurodegenerative disease. WWOX binds Tau via its C-terminal SDR domain and interacts with Tau phosphorylating enzymes ERK, JNK, and GSK-3β, and thereby limits AD progression. Loss of WWOX in newborns leads to severe neural diseases and early death. Gradual loss of WWOX protein in the hippocampus and cortex starting from middle age may slowly induce aggregation of a protein cascade that ultimately causes accumulation of extracellular amyloid beta plaques and intracellular tau tangles, along with reduction in inhibitory GABAergic interneurons, in AD patients over 70 years old. Age-related increases in pS14-WWOX accumulation in the brain promotes neuronal degeneration. Suppression of Ser14 phosphorylation by a small peptide Zfra leads to enhanced protein degradation, reduction in NF-κB-mediated inflammation, and restoration of memory loss in triple transgenic mice for AD. Intriguingly, tumor suppressors p53 and WWOX may counteract each other in vivo, which leads to upregulation of AD-related protein aggregation in the brain and lung. WWOX has numerous binding proteins. We reported that the stronger the binding between WWOX and its partners, the better the suppression of cancer growth and reduction in inflammation. In this regard, the stronger complex formation between WWOX and partners may provide a better blockade of AD progression. In this review, we describe whether and how WWOX and partner proteins control inflammatory response and protein aggregation and thereby limit AD progression.

Synergistic effect of toosendanin and regorafenib against cell proliferation and migration by regulating WWOX signaling pathway in hepatocellular carcinoma

Regorafenib (RGF), a second-line multi-kinase inhibitor in the treatment of HCC (hepatocellular carcinoma) after sorafenib failure, exposes to the risk of drug resistance and subsequent progression of HCC patients. Toosendanin (TSN), a triterpenoid has presented excellent inhibition on several tumors. The purpose of this study is to investigate the inhibitory effect of the combination of TSN and RGF on HCC cells. We identified that TSN and RGF combination (TRC) synergistically inhibited the proliferation and migration of MHCC-97L cells. The upregulation of WWOX (WW-domain containing oxidoreductase) played a vital role in the HCC cell growth treated with TRC. TRC suppressed the phosphorylation of Stat3 and expression of DVL2, negatively regulated the activity of β-catenin by promoting the phosphorylation of GSK3β. In addition, the intranuclear proteins, including MMP2, MMP9, and C-MYC were significantly inhibited by TRC. The in vivo xenograft models confirmed that TRC effectually prevented the tumor growth through upregulating WWOX. Therefore, the treatment of TRC may be a potential solution of RGF resistance and promising therapeutic method in malignant HCC.

Molecular Functions of WWOX Potentially Involved in Cancer Development

The WW domain-containing oxidoreductase gene (WWOX) was cloned 21 years ago as a putative tumor suppressor gene mapping to chromosomal fragile site FRA16D. The localization of WWOX in a chromosomal region frequently altered in human cancers has initiated multiple current studies to establish its role in this disease. All of this work suggests that WWOX, due to its ability to interact with a large number of partners, exerts its tumor suppressive activity through a wide variety of molecular actions that are mostly cell specific.

Stress kinases in the development of liver steatosis and hepatocellular carcinoma

Non-alcoholic fatty liver disease (NAFLD) is an important component of metabolic syndrome and one of the most prevalent liver diseases worldwide. This disorder is closely linked to hepatic insulin resistance, lipotoxicity, and inflammation. Although the mechanisms that cause steatosis and chronic liver injury in NAFLD remain unclear, a key component of this process is the activation of stress-activated kinases (SAPKs), including p38 and JNK in the liver and immune system. This review summarizes findings which indicate that the dysregulation of stress kinases plays a fundamental role in the development of steatosis and are important players in inducing liver fibrosis. To avoid the development of steatohepatitis and liver cancer, SAPK activity must be tightly regulated not only in the hepatocytes but also in other tissues, including cells of the immune system. Possible cellular mechanisms of SAPK actions are discussed.

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Hepatic JNK triggers steatosis and insulin resistance, decreasing lipid oxidation and ketogenesis in HFD-fed mice.

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Decreased liver expression of p38α/β in HFD increases lipogenesis.

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Hepatic p38γ/δ drive insulin resistance and inhibit autophagy, which may lead to steatosis.

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Macrophage p38α/β promote cytokine production and M1 polarization, leading to lipid accumulation in hepatocytes.

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Myeloid p38γ/δ contribute to cytokine production and neutrophil migration, protecting against steatosis, diabetes and NAFLD.

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JNK1 and p38γ induce HCC while p38α blocks it. However, deletion of hepatic JNK1/2 induces cholangiocarcinoma.

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SAPK are potential therapeutic target for metabolic disorders, steatohepatitis and liver cancer.

LncRNA NBR2 inhibits tumorigenesis by regulating autophagy in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) have been identified to play increasingly important roles in tumorigenesis, and they may serve as novel biomarkers for cancer therapy. LncRNA NBR2 (neighbor of BRCA1 gene 2), a novel identified lncRNA, is demonstrated to decrease in several cancers. However, it is still unknown whether lncRNA NBR2 is involved in hepatocellular carcinoma and autophagy. We found that HCC cases with lower NBR2 expression had significantly worse overall survival than those with higher NBR2 expression in advanced patients. And the expression of NBR2 was negatively correlated with the degree of malignancy of HCC cell lines and differentiation of hepatocellular carcinoma. Besides, NBR2 inhibited the proliferation, invasion, and migration of liver cancer cells. We further found that NBR2 repressed cytoprotective autophagy to restrain HCC cell proliferation. Moreover, NBR2 inhibited Beclin 1-dependent autophagy through ERK and JNK pathways. Taken together, NBR2 suppressed autophagy-induced cell proliferation at least partly through ERK and JNK pathways. These data indicated that NBR2 served as a tumor suppressor gene in hepatocellular carcinoma. The current study provides a novel insight and treatment strategy for hepatocellular carcinoma.

A long non-coding RNA TSLD8 inhibits hepatocellular carcinoma by stabilizing WWOX

The hepatocellular carcinoma (HCC) is a common and highly aggressive malignancy especially in China. Accumulating data have shown a critical role of long non-coding RNAs (lncRNAs) during cancer progression. However, the function of lncRNA TSLD8 remains elusive. By lncRNA profiling, we identify a novel lncRNA termed TSLD8 in HCC. TSLD8 expression is significantly lowered in HCC tissues and cell lines. TSLD8 facilitates migration and viability in SMMC-7721 and HepG2 cells. Furthermore, TSLD8 can interact with WWOX and protect WWOX from proteasome-mediated degradation. Using PuPGEA-based nanocomplex for gene delivery, we found that co-delivery of TSLD8 and WWOX may exhibit synergistic and additive effects to inhibit HCC progression. PuPGEA-based nanocomplex delivery does not substantially alter the blood chemistries (e.g. alkaline phosphatase, blood urea nitrogen, aspartate aminotransferase, alanine aminotransferase) or initiate immune responses implying a safe strategy. Collectively, our current study has identified a novel tumor suppressive lncRNA TSLD8 which exerts its tumor suppressive function by stabilizing WWOX. Co-delivery of TSLD8 and WWOX via PuPGEA-based nanocomplexes might provide promising therapeutics for eradicating HCC.

Expression of B Cell-Specific Moloney Murine Leukemia Virus Integration Site 1 (BMI-1) and WW Domain-Containing Oxidoreductase (WWOX) in Liver Cancer Tissue and Normal Liver Tissue

Background

The aim of this study was to compare the expression levels of mRNA of the B cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) and the WW domain-containing oxidoreductase (WWOX) genes and their protein products in tissues from patients with liver cancer with normal liver tissues from patients without liver cancer.

Material/Methods

The liver cancer group (N=56) included patients with available tissue samples of histologically confirmed liver cancer. The control group (N=24) included histologically confirmed normal liver tissue samples. Immunofluorescence staining and Western blot were used to detect and compare protein expression of Bmi-1 and WWOX in liver tissues in the liver cancer group and the control group. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect and compare mRNA expression of BMI-1 and WWOX in liver tissues in the liver cancer group and the control group. Expression levels of the protein and mRNA levels and the clinicopathological features including patient prognosis in liver cancer were evaluated statistically using analysis of variance (ANOVA).

Results

There were significant differences in the expression levels of protein and mRNA of BMI-1 and WWOX between the liver cancer group and the control group. BMI-1 mRNA and protein expression were significantly increased, and WWOX mRNA and protein expression were significantly reduced in liver cancer tissue, compared with normal liver tissue (p<0.05).

Conclusions

In liver cancer tissue compared with normal liver, the expression of BMI-1 and WWOX mRNA and their protein products were upregulated and down-regulated, respectively.

WWOX Tumor Suppressor Gene in Breast Cancer, a Historical Perspective and Future Directions

The WWOX tumor suppressor gene is located at 16q23. 1–23.2, which covers the region of FRA16D—a common fragile sites. Deletions within the WWOX coding sequence are observed in up to 80% of breast cancer cases, which makes it one of the most common genetic alterations in this tumor type. The WWOX gene is known to play a role in breast cancer: increased expression of WWOX inhibits cell proliferation in suspension, reduces tumor growth rates in xenographic transplants, but also enhances cell migration through the basal membrane and contributes to morphological changes in 3D matrix-based cell cultures. The WWOX protein may act in several ways, as it has three functional domains—two WW domains, responsible for protein-protein interactions and an SDR domain (short dehydrogenase/reductase domain) which catalyzes conversions of low molecular weight ligands, most likely steroids. In epithelial cells, WWOX modulates gene transcription through interaction with p73, AP-2γ, and ERBB4 proteins. In steroid hormone-regulated tissues like mammary gland epithelium, the WWOX SDR domain acts as a steroid dehydrogenase. The relationship between WWOX and hormone receptors was shown in an animal model, where WWOX(C3H)+/–mice exhibited loss of both ER and PR receptors. Moreover, in breast cancer specimens, a positive correlation was observed between WWOX expression and ER status. On the other hand, decreased WWOX expression was associated with worse prognosis, namely higher relapse and mortality rates in BC patients. Recently, it was shown that genomic instability might be driven by the loss of WWOX expression. It was reported that WWOX plays role in DNA damage response (DDR) and DNA repair by regulating ATM activation through physical interaction. A genome caretaker function has also been proposed for WWOX, as it was found that WWOX sufficiency decreases homology directed repair (HDR) and supports non-homologous end-joining (NHEJ) repair as the dominant DSB repair pathway by Brca1-Wwox interaction. In breast cancer cells, WWOX was also found to modulate the expression of glycolysis pathway genes, through hypoxia-inducible transcription factor 1α (HIF1α) regulation. The paper presents the current state of knowledge regarding the WWOX tumor suppressor gene in breast cancer, as well as future research perspectives.

WWOX Phosphorylation, Signaling, and Role in Neurodegeneration

Homozygous null mutation of tumor suppressor WWOX/Wwox gene leads to severe neural diseases, metabolic disorders and early death in the newborns of humans, mice and rats. WWOX is frequently downregulated in the hippocampi of patients with Alzheimer’s disease (AD). In vitro analysis revealed that knockdown of WWOX protein in neuroblastoma cells results in aggregation of TRAPPC6AΔ, TIAF1, amyloid β, and Tau in a sequential manner. Indeed, TRAPPC6AΔ and TIAF1, but not tau and amyloid β, aggregates are present in the brains of healthy mid-aged individuals. It is reasonable to assume that very slow activation of a protein aggregation cascade starts sequentially with TRAPPC6AΔ and TIAF1 aggregation at mid-ages, then caspase activation and APP de-phosphorylation and degradation, and final accumulation of amyloid β and Tau aggregates in the brains at greater than 70 years old. WWOX binds Tau-hyperphosphorylating enzymes (e.g., GSK-3β) and blocks their functions, thereby supporting neuronal survival and differentiation. As a neuronal protective hormone, 17β-estradiol (E2) binds WWOX at an NSYK motif in the C-terminal SDR (short-chain alcohol dehydrogenase/reductase) domain. In this review, we discuss how WWOX and E2 block protein aggregation during neurodegeneration, and how a 31-amino-acid zinc finger-like Zfra peptide restores memory loss in mice.

Low expression of WW domain-containing oxidoreductase associates with hepatocellular carcinoma aggressiveness and recurrence after curative resection

WW domain‐containing oxidoreductase (WWOX), which has a protein‐interaction domain and is regarded to be a tumor suppressor, has been known to play an important role in anti‐angiogenesis and cancer progression. This study aimed to investigate prognostic values of WWOX expression in hepatocellular carcinoma (HCC) patients after hepatectomy. Additionally, we intended to formulate a valuable prognostic nomogram for HCCs. 182 HCC patients who underwent hepatectomy from January 2009 to January 2010 were enrolled in our study. qRT‐PCR, Western blot, and immunohistochemistry on tissue microarrays were then used to determine the expression levels of WWOX. An evaluation of the role of WWOX expression levels in the prognosis and outcome of patients was established. A decrease in the expression of WWOX was found when compared to adjacent tumor‐free tissues, which led to worse overall survival (OS) and recurrence‐free survival (RFS) and, therefore, was considered as an independent negative factor in the prognosis of HCC. Two nomograms, comprising WWOX, alpha‐fetoprotein (AFP), tumor size, and γ‐glutamyltransferase (γ‐GT), were constructed to obtain superior discriminatory abilities than conventional staging systems in terms of C‐index and clinical net benefit on decision curve analysis (DCA) for OS and RFS. Our data suggest that WWOX expression is strongly related to HCC post‐resection aggressiveness and recurrence. Additional advanced and accurate predictive model through the incorporation of WWOX into nomogram could help predict OS or RFS for HCC patients.

Association of WWOX rs9926344 polymorphism with poor prognosis of hepatocellular carcinoma

Introduction: The WW domain-containing oxidoreductase (WWOX), widely expressed in human tissues, is considered as a tumor suppressor gene and plays an important role in the incidence and progression of human cancer, HCC included. This study was to investigate the correlation between single nucleotide polymorphisms (SNPs) of the WWOX gene and the prognosis of hepatocellular carcinoma (HCC) patients.

Materials and Methods: After a total of 152 HCC patients were recruited, 8 cases with tumor recurrence within 2-years after operation and 8 cases without recurrence were selected randomly for SNP genotyping and screening using Affymetrix Array 6.0. And then we confirmed candidate SNPs in the remaining 136 patients by time-of-flight mass spectrometry (TOF-MS).

Results: In total, 32 SNPs were screened and identified as candidate SNPs with one SNP in particular, (rs9926344), being further verified to be valuable. We found that AA+AG genotype and A allele of WWOX rs9926344 were significantly associated with recurrent risk of HCC (p=0.002 and p=0.001, respectively). The Kaplan-Meier curve showed that patients carrying rs9926344 AA +AG genotype had poor RFS (P=0.004) and OS (P=0.005) compared to those carrying GG genotypes. The multivariate COX regression analysis showed that the AA+AG genotype were an independent prognostic factor for tumor recurrence (HR 1.787, 95% CI 1.042-3.064, P=0.035). Furthermore, IHC analysis showed that the WWOX protein down-regulation is more frequent in patients with AG genotype compared to those with GG genotype (P=0.023).

Conclusion: Our findings indicate that WWOX rs9926344 polymorphism is positively correlated with tumor recurrence and can be used as an independent prognostic marker for HCC patients after operation.

Correlation of expression of WWOX and JNK with clinicopathologic features in human breast carcinoma

The aim of our study was to compare the expression levels of c-Jun N-terminal kinase (JNK) and WW domain-containing oxidoreductase (WWOX) in human breast carcinoma, to analyze the correlation between the expression of WWOX and JNK with the clinicopathologic features of human breast carcinoma, and to explore the potential mechanism of their antitumor effects. The mRNA and protein levels of WWOX and JNK in forty paired breast carcinoma tissues and the adjacent normal tissues were detected by real-time quantitative polymerase chain reaction (RT-PCR) and Western blot analysis. Protein expression was further confirmed by immunohistochemistry (IHC). The mRNA expression levels of both JNK and WWOX were downregulated in carcinoma tissues relative to those in the adjacent normal tissues, as determined by Western blot analysis and IHC (P<0.01). JNK expression was positively correlated with WWOX expression (r=0.47, P=0.002). Both WWOX and JNK play important roles in breast cancer. Therefore, the antitumor ability of WWOX and JNK could supply significant information for therapeutic strategy.

Magnolol and honokiol exert a synergistic anti-tumor effect through autophagy and apoptosis in human glioblastomas

Glioblastoma (GBM) is a malignant brain tumor associated with a high mortality rate. The aim of this study is to investigate the synergistic effects of honokiol (Hono) and magnolol (Mag), extracted from Magnolia officinalis, on cytotoxicity and inhibition of human GBM tumor progression in cellular and animal models. In comparison with Hono or Mag alone, co-treatment with Hono and Mag (Hono-Mag) decreased cyclin A, D1 and cyclin-dependent kinase 2, 4, 6 significantly, leading to cell cycle arrest in U87MG and LN229 human glioma cells. In addition, phosphorylated phosphoinositide 3-kinase (p-PI3K), p-Akt, and Ki67 were decreased after Hono-Mag treatment, showing proliferation inhibition. Hono-Mag treatment also reduced p-p38 and p-JNK but elevated p-ERK expression. Besides, Hono-Mag treatment induced autophagy and intrinsic and extrinsic apoptosis. Both ERK and autophagy inhibitors enhanced Hono-Mag-induced apoptosis in LN229 cells, indicating a rescuer role of ERK. In human GBM orthotopic xenograft model, the Hono-Mag treatment inhibited the tumor progression and induced apoptosis more efficiently than Temozolomide, Hono, or Mag group. In conclusion, the Hono-Mag exerts a synergistic anti-tumor effect by inhibiting cell proliferation and inducing autophagy and apoptosis in human GBM cells. The Hono-Mag may be applied as an adjuvant therapy to improve the therapeutic efficacy of GBM treatment.

WWOX suppresses proliferation and induces apoptosis via G2 arrest and caspase 3 pathway in nasopharyngeal carcinoma cells

BACKGROUND

WWOX plays crucial roles in various tumors. However, so far, minimal research into the role of WWOX in the development of nasopharyngeal carcinoma (NPC) has been reported. The present study investigates the effects of WWOX overexpression on cell proliferation, migration, and invasion in human NPC cell line CNE1.

MATERIALS AND METHODS

A lentiviral vector carrying WWOX was transfected into CNE1 cells. The mRNA abundances of WWOX, MMP9, E-cadherin and WWOX protein were detected using quantitative RT-PCR and Western blotting in the transfected cells compared with the control cells (cells transfected using the empty vector and untransfected cells), respectively. Cell proliferation rates were assessed by plate colony formation assays and methyl thiazolyl tetrazolium (MTT). Cell migration and invasion were tested through wound healing assays and/or transwell migration and invasion assays. Cell cycle progression and apoptosis assays were performed by flow cytometry. The protein abundances of activated fragments of caspase-3, cleaved caspase-3 and AKT, phosphorylated p-AKT (Ser473) were measured using Western blotting.

RESULTS

Overexpression of WWOX significantly inhibited cell proliferation, migration and invasion and induced apoptosis. Moreover, WWOX overexpression led to cell proliferation inhibition via induction of cell cycle arrest in G2/M phase. WWOX suppressed migration and invasion via downregulation of MMP9 and upregulation of E-cadherin. Meanwhile, WWOX could downregulate the phosphorylation of Akt protein kinase and upregulate cleavage of Caspase-3, contributing to inhibition of proliferation and promotion of apoptosis.

CONCLUSION

WWOX gene may be a novel target for gene therapy in NPC.

Role of C-Jun N-terminal Kinase in Hepatocellular Carcinoma Development

Hepatocellular carcinoma (HCC) is among the most frequently occurring cancers and the leading causes of cancer mortality worldwide. Identification of the signaling pathways regulating liver carcinogenesis is critical for developing novel chemoprevention and targeted therapies. C-Jun N-terminal kinase (JNK) is a member of a larger group of serine/threonine (Ser/Thr) protein kinases known as the mitogen-activated protein kinase (MAPK) family. JNK is an important signaling component that converts external stimuli into a wide range of cellular responses, including cell proliferation, differentiation, survival, migration, invasion, and apoptosis, as well as the development of inflammation, fibrosis, cancer growth, and metabolic diseases. Because of the essential roles of JNK in these cellular functions, deregulated JNK is often found to contribute to the development of HCC. Recently, the functions and molecular mechanisms of JNK in HCC development have been addressed using mouse models and human HCC cell lines. Furthermore, recent studies demonstrate that the activation of JNK by oncogenes can promote the development of cancers by regulating the transforming growth factor (TGF)-β/Smad pathway, which makes the oncogenes/JNK/Smad signaling pathway an attractive target for cancer therapy. Additionally, JNK-targeted therapy has a broad potential for clinical applications. In summary, we are convinced that promising new avenues for the treatment of HCC by targeting JNK are on the horizon, which will undoubtedly lead to better, more effective, and faster therapies in the years to come.

Combinations of single nucleotide polymorphisms WWOX-rs13338697, GALNT14-rs9679162 and rs6025211 effectively stratify outcomes of chemotherapy in advanced hepatocellular carcinoma

AIM

A genome-wide association study (GWAS) had identified a single nucleotide polymorphism (SNP), GALNT14-rs9679162, capable of predicting chemotherapy responses in advanced hepatocellular carcinoma (HCC). Here, we revisited the GWAS database to search for necessary SNPs that could improve our outcome prediction.

METHODS

A cohort of 116 HCC patients receiving split-dose chemotherapy composed of 5-fluorouracil, mitoxantrone and cisplatin was enrolled. The GALNT14-rs9679162 together with four other leading candidate SNPs (rs6025211, rs715171, LOC105369482-rs1955024 and WWOX-rs13338697) was genotyped and correlated with time-to-tumor progression (TTP) and overall survival (OS).

RESULTS

GALNT14-rs9679162-TT genotype remained an effective predictor for favorable TTP and OS (P = 0.012 and 0.002). Additionally, it was found that WWOX-rs13338697-CT genotype was associated with unfavorable TTP (P = 0.031), independent of GALNT14-rs9679162 genotype (adjusted P = 0.045), and rs6025211-CT genotype was associated with unfavorable OS (P = 0.014), independent of GALNT14-rs9679162 genotype (adjusted P = 0.025). Combinations of these SNPs stratified patients into three groups with differential treatment outcomes. Patients with GALNT14-rs9679162-TT/WWOX-rs13338697-non-CT genotypes achieved the most favorable treatment outcomes (n = 19; median TTP, median OS and response rate were 3.9 months, 6.8 months and 4/19 [21.1%], respectively); whereas patients with GALNT14-rs9679162-non-TT/rs6025211-CT genotypes associated with the most unfavorable treatment outcomes (n = 40; median TTP, median OS and response rate were 1.9 months, 3.5 months and 1/40 [2.5%], respectively). The remaining patients constituted a third subgroup with intermediate clinical outcomes.

CONCLUSIONS

Three genetic variants, GALNT14-rs9679162, WWOX-rs13338697 and rs6025211, stratified advanced HCC patients into three groups with differential treatment outcomes.

Atypical regulators of Wnt/β-catenin signaling as potential therapeutic targets in Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the most common causes of cancer-related death worldwide. Hepatocellular carcinoma development depends on the inhibition and activation of multiple vital pathways, including the Wnt signaling pathway. The Wnt/β-catenin pathway lies at the center of various signaling pathways that regulate embryonic development, tissue homeostasis and cancers. Activation of the Wnt/β-catenin pathway has been observed frequently in hepatocellular carcinoma. However, activating mutations in β-catenin, Axin and Adenomatous Polyposis Coli only contribute to a portion of the Wnt signaling hyper-activation observed in hepatocellular carcinoma. Therefore, besides mutations in the canonical Wnt components, there must be additional atypical regulation or regulators during Wnt signaling activation that promote liver carcinogenesis. In this mini-review, we have tried to summarize some of these well-established factors and to highlight some recently identified novel factors in the Wnt/β-catenin signaling pathway in hepatocellular carcinoma. Impact statement Early recurrence of human hepatocellular carcinoma (HCC) is a frequent cause of poor survival after potentially curative liver resection. Among the deregulated signaling cascades in HCC, evidence indicates that alterations in the Wnt/β-catenin signaling pathway play key roles in hepatocarcinogenesis. In this review, we summarize the potential molecular mechanisms how the microtubule-associated Protein regulator of cytokinesis 1 (PRC1), a direct Wnt signaling target previously identified in our laboratory to be up-regulated in HCC, in promoting cancer proliferation, stemness, metastasis and tumorigenesis through a complex regulatory circuitry of Wnt3a activities.

Epigenetic silencing of BCL6B inactivates p53 signaling and causes human hepatocellular carcinoma cell resist to 5-FU

BCL6B is a potential tumor suppressor in human gastric cancer, but the regulation and mechanism of BCL6B in human hepatocellular carcinogenesis remain unclear. This study is to explore the epigenetic change and mechanism of BCL6B in human hepatocellular carcinoma (HCC). Nineteen hepatic cancer cell lines, 50 cases of adjacent tissue and 149 cases of HCC samples were employed. BCL6B is methylated in 100% (19/19) of human HCC cell lines, 40.0% (20/50) of adjacent tissue samples and 86.6% (129/149) of primary cancer samples. Methylation of BCL6B is associated with HBV positive (p < 0.05). But no association was found with age, sex, tumor size, differentiation, TNM stage, recurrence and survival. Loss of BCL6B expression was found in 19 of completely methylated HCC cell lines. BCL6B was re-expressed after 5-aza-2′-deoxycytidine treatment. Restoration of BCL6B expression suppressed cell proliferation, induced apoptosis and G1/S arrest in HCC cells. The expression of EGR1, a key component of p53 signaling, was increased after re-expression BCL6B in HCC cells. Re-expression of BCL6B activated p53 signaling and sensitized HCC cells to 5-fluorouracil. BCL6B is frequently methylated in human HCC and the expression of BCL6B is regulated by promoter region hypermethylation. BCL6B activates p53 signaling by increasing EGR1 expression in HCC.

MicroRNA-153 promotes Wnt/β-catenin activation in hepatocellular carcinoma through suppression of WWOX

Persistent activation of Wnt/β-catenin signaling plays crucial roles in the development of human cancers, including hepatocellular carcinoma (HCC). Here, we performed a MicroRNA-based genetic screen, which revealed a novel diversion in β-catenin signaling triggered by MicroRNA-153 (miR-153). Overexpression of miR-153 was able to promote β-catenin transcriptional activity, leading to cell-cycle progression, proliferation and colony formation of HCC cells. Additionally, systemic administration of miR-153 antigomir suppressed hepatocellular carcinogenesis in a murine liver cancer model. At the molecular level, we found that miR-153 inhibited protein level of WWOX, a tumor suppressor and inhibitor of β-catenin signaling, through targeting its 3′-untranslated region. Therefore, our study highlights the importance of MicroRNA-153/WWOX/β-catenin regulatory axis in the HCC tumorigenesis.

Alteration of WWOX in human cancer: a clinical view

WWOX gene is located in FRA16D, the highly affected chromosomal fragile site. Its tumor suppressor activity has been proposed on a basis of numerous genomic alterations reported in chromosome 16q23.3-24.1 locus. WWOX is affected in many cancers, showing as high as 80% loss of heterozygosity in breast tumors. Unlike most tumor suppressors impairing of both alleles of WWOX is very rare. Despite cellular and animal models information on a WWOX role in cancer tissue is limited and sometimes confusing. This review summarizes information on WWOX in human tumors.

Association of downregulation of WWOX with poor prognosis in patients with intrahepatic cholangiocarcinoma after curative resection

BACKGROUND AND AIM

Downregulation of the WW domain containing oxidoreductase (WWOX) has been reported to be involved in tumorigenesis in several neoplasms. This study sought to investigate the expression and role of WWOX in intrahepatic cholangiocarcinoma (ICC).

METHODS

WWOX expression was measured by quantitative real-time polymerase chain reaction (PCR), immunoblot, immunofluorescence, and immunohistochemistry. The prognostic significance was assessed by Kaplan-Meier and Cox regression analyses. The role of WWOX in proliferation, anchorage-independent growth, gene expression regulation, and tumorigenesis was assessed by WWOX re-expression using lentivirus. Methylation-specific PCR was performed to evaluate the methylation status of the WWOX gene regulatory region. A DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (AZA), was used to activate the endogenous WWOX gene in ICC cells both in vitro and in vivo.

RESULTS

The expression of WWOX in ICC tissues was much lower than that in nontumorous samples and showed reverse correlation with proliferative status. Restoration of WWOX expression resulted in suppression of the growth of WWOX-deficient ICC cells through activation of the intrinsic apoptotic signaling pathway, but did not affect growth of WWOX-sufficient human intrahepatic biliary epithelial derived non-cancer cells. Multivariate analyses revealed that downregulation of WWOX was an unfavorable predictor for overall survival and cumulative recurrence rates. The WWOX gene regulatory region was frequently methylated in ICC tissues and cell lines, and intratumoral WWOX restoration, through AZA injection, suppressed tumor growth in nude mice.

CONCLUSION

Downregulation of WWOX may occur as a result of hypermethylation and implies a poor prognosis in ICC; WWOX re-expression may be a potential molecular therapeutic target for ICC.

Regulation of cell signaling and apoptosis by tumor suppressor WWOX

Human fragile WWOX gene encodes a tumor suppressor WW domain-containing oxidoreductase (named WWOX, FOR, or WOX1). Functional suppression of WWOX prevents apoptotic cell death induced by a variety of stress stimuli, such as tumor necrosis factor, UV radiation, and chemotherapeutic drug treatment. Loss of WWOX gene expression due to gene deletions, loss of heterozygosity, chromosomal translocations, or epigenetic silencing is frequently observed in human malignant cancer cells. Acquisition of chemoresistance in squamous cell carcinoma, osteosarcoma, and breast cancer cells is associated with WWOX deficiency. WWOX protein physically interacts with many signaling molecules and exerts its regulatory effects on gene transcription and protein stability and subcellular localization to control cell survival, proliferation, differentiation, autophagy, and metabolism. In this review, we provide an overview of the recent advances in understanding the molecular mechanisms by which WWOX regulates cellular functions and stress responses. A potential scenario is that activation of WWOX by anticancer drugs is needed to overcome chemoresistance and trigger cancer cell death, suggesting that WWOX can be regarded as a prognostic marker and a candidate molecule for targeted cancer therapies.

WWOX, large common fragile site genes, and cancer

WWOX is a gene that spans an extremely large chromosomal region. It is derived from within chromosomal band 16q23.2 which is a region with frequent deletions and other alterations in a variety of different cancers. This chromosomal band also contains the FRA16D common fragile site (CFS). CFSs are chromosomal regions found in all individuals which are highly unstable. WWOX has also been demonstrated to function as a tumor suppressor that is involved in the development of many cancers. Two other highly unstable CFSs, FRA3B (3p14.2) and FRA6E (6q26), also span extremely large genes, FHIT and PARK2, respectively, and these two genes are also found to be important tumor suppressors. There are a number of interesting similarities between these three large CFS genes. In spite of the fact that they are derived from some of the most unstable chromosomal regions in the genome, they are found to be highly evolutionarily conserved and the chromosomal region spanning the mouse homologs of both WWOX and FHIT are also CFSs in mice. Many of the other CFSs also span extremely large genes and many of these are very attractive tumor suppressor candidates. WWOX is therefore a member of a very interesting family of very large CFS genes.

Very large common fragile site genes and their potential role in cancer development

Common fragile sites (CFSs) are large chromosomal regions that are hot-spots for alterations especially within cancer cells. The three most frequently expressed CFS regions (FRA3B, FRA16D and FRA6E) contain genes that span extremely large genomic regions (FHIT, WWOX and PARK2, respectively), and these genes were found to function as important tumor suppressors. Many other CFS regions contain extremely large genes that are also targets of alterations in multiple cancers, but none have yet been demonstrated to function as tumor suppressors. The loss of expression of just FHIT or WWOX has been found to be associated with a worse overall clinical outcome. Studies in different cancers have revealed that some cancers have decreased expression of multiple large CFS genes. This loss of expression could have a profound phenotypic effect on these cells. In this review, we will summarize the known large common fragile site genes and discuss their potential relationship to cancer development.

WWOX modulates the gene expression profile in the T98G glioblastoma cell line rendering its phenotype less malignant

The aim of the present study was to assess the influence of WWOX gene upregulation on the transcriptome and phenotype of the T98G glioblastoma cell line. The cells with high WWOX expression demonstrated a significantly different transcription profile for approximately 3,000 genes. The main cellular pathways affected were Wnt, TGFβ, Notch and Hedgehog. Moreover, the WWOX-transfected cells proliferated at less than half the rate, exhibited greatly lowered adhesion to ECM, increased apoptosis and impaired 3D culture formation. They also demonstrated an increased ability for crossing the basement membrane. Our results indicate that WWOX, apart from its tumor-suppressor function, appears to be a key regulator of the main cellular functions of the cell cycle and apoptosis. Furthermore, our results showed that WWOX may be involved in controlling metabolism, cytoskeletal structure and differentiation.

Upregulation of the putative oncogene COTE1 contributes to human hepatocarcinogenesis through modulation of WWOX signaling

Family with sequence similarity 189, also known as COTE1, has been found to be significantly upregulated in hepatocellular carcinoma (HCC) specimens and cell lines and is associated with tumor size and differentiation. Furthermore, COTE1 contributes to hepatocellular carcinogenesis. The overexpression of COTE1 enhanced in vitro cell viability and colony formation in soft agar, and in vivo tumorigenicity of HCC-derived Focus and Huh7 cells. In contrast, COTE1 knockdown via RNAi markedly suppressed these phenotypes in YY-8103 and WRL-68 HCC cell lines. Mechanistic analyses indicated that COTE1 physically associated with WW domain-containing oxidoreductase (WWOX) and modulated WWOX tyrosine phosphorylation. The ectopic overexpression of COTE1 inhibited the WWOX-p53 signaling pathway by reducing the phosphorylation of WWOX at the Tyr33 residue in Focus cells. Conversely, COTE1 silencing activated tyrosine 33 phosphorylation of WWOX and induced WWOX-p53 mediated mitochondrial apoptosis in WRL-68 cells. In addition, COTE1 upregulation in Huh7 cells blocked the WWOX-cyclin D1 pathway via dephosphorylation of WWOX Tyr287, stimulating cell cycle progression whereas phosphorylation of Tyr287 of WWOX induced by COTE1 silencing resulted in activation of WWOX-cyclin D1 signaling, leading to cell cycle arrest in YY-8103 cells. Together, our findings suggest that the cytoplasmic protein COTE1 contributes to HCC tumorigenesis by regulating cell proliferation through the modulation of WWOX signaling.

WW domain-containing oxidoreductase's role in myriad cancers: clinical significance and future implications

The WW domain-containing oxidoreductase (WWOX) gene, encodes a tumor suppressor located on 16q23.1, spanning FRA16D, one of the most active common fragile sites in the human genome, that is altered in numerous types of cancer. WWOX's alteration in these myriad cancers is due to disparate mechanisms including loss of heterozygosity, homozygous deletion and epigenetic changes. In vitro, WWOX has been found to be reduced or absent in numerous cancer cell lines and WWOX restoration has been found to inhibit tumor cell growth and invasion. Wwox knockout mice developed femoral focal lesions resembling osteosarcomas within one month of their life and aging Wwox heterozygous mice have an increased incidence of spontaneous lung and mammary tumors as well as B-cell lymphomas. We herein review WWOX's role that has been unearthed thus far in different types of malignancies, its clinical significance and future implications.

Role of WWOX and NF-κB in lung cancer progression

It is generally agreed that the pro-inflammatory, pro-survival transcription factor NF-κB is a tumor promoter. Tumor necrosis factor alpha (TNF-α or TNF) mediates NF-κB activation. Tumor suppressor WWOX (FOR or WOX1) is a downstream effector of the TNF signaling. Thus, activation of both WWOX (FOR or WOX1) and NF-κB may occur during TNF signaling and/or under stress conditions. Indeed, the first WW domain of WWOX induces the activation of NF-κB-responsive promoter without TNF participation. It appears that WWOX counteracts with NF-κB in regulating cell survival and death. For example, WWOX becomes activated with Tyr33 phosphorylation and relocates together with NF-κB and many transcription factors to the nucleus to cause neuronal death in sciatic nerve-transected rats. While WWOX is frequently lost in lung cancer and many other cancers, NF-κB activation-induced cancer promotion probably requires WWOX-independent signaling networks to induce expression of pro-survival factors. The antagonistic role of WWOX and NF-κB in the regulation of lung cancer progression is discussed.

The WWOX tumor suppressor gene in endometrial adenocarcinoma

Endometrial cancer is a lethal malignancy, the causes of which remain to be determined. The aim of the present study, carried out on tumor samples from 79 patients, was to evaluate the role of the WWOX tumor suppressor gene in endometrial adenocarcinoma. The expression levels of WWOX and its protein content were assessed in normal endometrium and cancer samples. Quantitative PCR was used to assess the correlation between the expression levels of WWOX and the genes involved in the proliferation (MKI67), apoptosis (BAX, BCL2), signal transduction (EGFR), cell cycle (CCNE1, CCND1), cell adhesion (CDH1) and transcription regulation (TP73, NCOR1). The relationship between loss of hetero-zygosity (LOH) and WWOX mRNA levels was also investigated using high resolution melting. Results of the present study demonstrated a positive correlation of WWOX expression with BCL2 and CCND1 and a negative correlation with BAX, CDH1, NCOR1 and BCL2/BAX ratio. The results also showed that loss of heterozygosity at two analyzed loci of the WWOX gene is frequent in patients with endometrial cancer and that WWOX expression levels are lower in tumor samples than in normal tissue. In conclusion, WWOX may be involved in endometrial cancer.

CYLD controls c-MYC expression through the JNK-dependent signaling pathway in hepatocellular carcinoma

Posttranslational modification of different proteins via direct ubiquitin attachment is vital for mediating various cellular processes. Cylindromatosis (CYLD), a deubiquitination enzyme, is able to cleave the polyubiquitin chains from the substrate and to regulate different signaling pathways. Loss, or reduced expression, of CYLD is observed in different types of human cancer, such as hepatocellular carcinoma (HCC). However, the molecular mechanism by which CYLD affects cancerogenesis has to date not been unveiled. The aim of the present study was to examine how CYLD regulates cellular functions and signaling pathways during hepatocancerogenesis. We found that mice lacking CYLD were highly susceptible to chemically induced liver cancer. The mechanism behind proved to be an elevated proliferation rate of hepatocytes, owing to sustained c-Jun N-terminal kinase 1 (JNK1)-mediated signaling via ubiquitination of TNF receptor-associated factor 2 and expression of c-MYC. Overexpression of wild-type CYLD in HCC cell lines prevented cell proliferation, without affecting apoptosis, adhesion and migration. A combined immunohistochemical and tissue microarray analysis of 81 human HCC tissues revealed that CYLD expression is negatively correlated with expression of proliferation markers Ki-67 and c-MYC. To conclude, we found that downregulation of CYLD induces tumor cell proliferation, consequently contributing to the aggressive growth of HCC. Our findings suggest that CYLD holds potential to serve as a marker for HCC progression, and its link to c-MYC via JNK1 may provide the foundation for new therapeutic strategies for HCC patients.

Ectopic overexpression of COTE1 promotes cellular invasion of hepatocellular carcinoma

Family with sequence similarity 189, member B (FAM189B), alias COTE1, a putative oncogene selected by microarray, for the first time was here found to be significantly up-regulated in hepatocellular carcinoma (HCC) specimens and HCC cell lines. mRNA expression of COTE1 in HCC samples and cell lines was detected by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR, while protein expression of COTE1 in HCC tissues was assessed by immunohistochemistry. In addition, invasion of HCC cells was observed after overexpressing or silencing COTE1. In the total of 48 paired HCC specimens, compared with the adjacent non-cancer tissues, the expression of COTE1 was up-regulated in 31 (p<0.01). In HCC cell lines, COTE1 expression was significantly higher than in normal human adult liver (p<0.01). Overexpression of COTE1 enhanced HCC-derived LM6 and MHCC-L cellular invasion in vitro. In contrast, COTE1 knockdown via RNAi markedly suppressed these phenotypes, as documented in LM3 and MHCC-H HCC cells. Mechanistic analyses indicated that COTE1 could physically associate with WW domain oxidoreductase (WWOX), a tumor suppressor. COTE1 may be closely correlated with invasion of hepatocellular carcinoma (HCC) cells and thus may serve as an effective target for gene therapy.

Self-aggregating TIAF1 in lung cancer progression

Recent studies have demonstrated that transforming growth factor beta (TGF-β1)-induced antiapoptotic factor (TIAF1) is able to form aggregates in the hippocampi of middle-aged normal individuals. The aggregating TIAF1 induces generation of amyloid beta (Aβ) for causing neurodegeneration. Intriguingly, TIAF1 aggregates are shown, together with Smad4 and Aβ, in the cancer stroma and peritumor capsules of many solid tumors. During lung cancer progression, for example, TIAF1 and amyloid fibrils are significantly upregulated in the cancer stroma. Aggregates of TIAF1 and Aβ are shown on the interface between metastatic lung cancer cells and the brain tissues. Conceivably, these peritumor materials are needed for cancer cells to survive. In vitro experiments revealed that TIAF1 is a crucial component for tumor suppressors p53 and WWOX-mediated tumor suppression and apoptosis. While metastatic lung cancer cells are frequently devoid of WWOX and p53, we provide new perspectives regarding the role of TIAF1 in the pathogenesis of lung cancer development, and propose a therapeutic approach for targeting TIAF1.

Functional and clinical characterization of the putative tumor suppressor WWOX in non-small cell lung cancer

INTRODUCTION

The oxidoreductase WWOX was initially described as a putative tumor suppressor in breast cancer. Non-small cell lung cancers (NSCLCs) frequently show aberrant WWOX expression. Herein, we characterized WWOX at a functional level in preclinical NSCLC models and in primary NSCLC biopsies.

METHODS

The human wild-type (wt) WWOX complementary DNA and a mutant WWOX with structurally disrupted short-chain dehydrogenase/reductase domain were conditionally expressed at physiological levels in several human NSCLC models. Resulting transgenic cell populations were analyzed with respect to clonogenic survival and apoptosis sensitivity in vitro and tumor growth in immune-deficient mice. Tissue microarrays prepared from surgically resected primary human NSCLC tumors were studied to correlate intratumoral WWOX expression with patient outcomes.

RESULTS

Conditional expression of wt WWOX, but not mutant WWOX, suppressed clonogenic survival of NSCLC cells in vitro and tumor growth in vivo. In addition, preserved intratumoral WWOX expression was associated with improved outcome in a cohort of 85 patients with surgically resected NSCLC. Unexpectedly, wt WWOX failed to sensitize NSCLC cells to various apoptotic stimuli but robustly protected against apoptosis induced by inhibitors of growth factor signal transduction.

CONCLUSIONS

WWOX acts as a tumor suppressor in human NSCLC models in a short-chain dehydrogenase/reductase domain-dependent manner. This activity is independent of sensitization to apoptotic cell death. WWOX expression as detected by immunohistochemistry may be a prognostic biomarker in surgically resected, early-stage NSCLC.

Global gene profiling of spontaneous hepatocellular carcinoma in B6C3F1 mice: similarities in the molecular landscape with human liver cancer

Hepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular pathogenesis of this disease is complex, and in general, treatment options remain poor. The use of rodent models to study human cancer has been extensively pursued, both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) two-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although major differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and molecular pathways dysregulated in mouse and human HCC. These data provide further support for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding the mechanisms of tumorigenesis resulting from chemical exposure in the NTP two-year carcinogenicity bioassay.

ShRNA-targeted MAP4K4 inhibits hepatocellular carcinoma growth

PURPOSE

Mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) is overexpressed in many types of cancer. Herein, we aimed to investigate its expression pattern, clinical significance, and biological function in hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

MAP4K4 expression was examined in 20 fresh HCCs and corresponding nontumor liver tissues. Immunohistochemistry for MAP4K4 was performed on additional 400 HCCs, of which 305 (76%) were positive for hepatitis B surface antigens. The clinical significance of MAP4K4 expression was analyzed. MAP4K4 downregulation was performed in HCC cell lines HepG2 and Hep3B with high abundance of MAP4K4, and the effects of MAP4K4 silencing on cell proliferation in vitro and tumor growth in vivo were evaluated. Quantitative real-time PCR arrays were employed to identify the MAP4K4-regulated signaling pathways.

RESULTS

MAP4K4 was aberrantly overexpressed in HCCs relative to adjacent nontumor liver tissues. This overexpression was significantly associated with larger tumor size, increased histologic grade, advanced tumor stage, and intrahepatic metastasis, as well as worse overall survival and higher early recurrence rate. Knockdown of the MAP4K4 expression reduced cell proliferation, blocked cell cycle at S phase, and increased apoptosis. The antitumor effects of MAP4K4 silencing were also observed in vivo, manifested as retarded tumor xenograft growth. Furthermore, multiple tumor progression-related signaling pathways including JNK, NFκB, and toll-like receptors were repressed by MAP4K4 downregulation.

CONCLUSIONS

MAP4K4 overexpression is an independent predictor of poor prognosis of HCC patients, and inhibition of its expression might be of therapeutic significance.

Cold and heat pattern of rheumatoid arthritis in traditional Chinese medicine: distinct molecular signatures indentified by microarray expression profiles in CD4-positive T cell

The research is aimed to explore the distinct molecular signatures in discriminating the rheumatoid arthritis patients with traditional Chinese medicine (TCM) cold pattern and heat pattern. Twenty patients with typical TCM cold pattern and heat pattern were included. Microarray technology was used to reveal gene expression profiles in CD4+ T cells. The signal intensity of each expressed gene was globally normalized using the R statistics program. The ratio of cold pattern to heat pattern in patients with RA at more or less than 1:2 was taken as the differential gene expression criteria. Protein-protein interaction information for these genes from databases was searched, and the highly connected regions were detected by IPCA algorithm. The significant pathways were extracted from these subnetworks by Biological Network Gene Ontology tool. Twenty-nine genes differentially regulated between cold pattern and heat pattern were found. Among them, 7 genes were expressed significantly more in cold pattern. Biological network of protein-protein interaction information for these significant genes were searched and four highly connected regions were detected by IPCA algorithm to infer significant complexes or pathways in the biological network. Particularly, the cold pattern was related to Toll-like receptor signaling pathway. The following related pathways in heat pattern were included: Calcium signaling pathway; cell adhesion molecules; PPAR signaling pathway; fatty acid metabolism. These results suggest that better knowledge of the main biological processes involved at a given pattern in TCM might help to choose the most appropriate treatment.

Dramatic co-activation of WWOX/WOX1 with CREB and NF-kappaB in delayed loss of small dorsal root ganglion neurons upon sciatic nerve transection in rats

BACKGROUND

Tumor suppressor WOX1 (also named WWOX or FOR) is known to participate in neuronal apoptosis in vivo. Here, we investigated the functional role of WOX1 and transcription factors in the delayed loss of axotomized neurons in dorsal root ganglia (DRG) in rats.

METHODOLOGY/PRINCIPAL FINDINGS

Sciatic nerve transection in rats rapidly induced JNK1 activation and upregulation of mRNA and protein expression of WOX1 in the injured DRG neurons in 30 min. Accumulation of p-WOX1, p-JNK1, p-CREB, p-c-Jun, NF-kappaB and ATF3 in the nuclei of injured neurons took place within hours or the first week of injury. At the second month, dramatic nuclear accumulation of WOX1 with CREB (>65% neurons) and NF-kappaB (40-65%) occurred essentially in small DRG neurons, followed by apoptosis at later months. WOX1 physically interacted with CREB most strongly in the nuclei as determined by FRET analysis. Immunoelectron microscopy revealed the complex formation of p-WOX1 with p-CREB and p-c-Jun in vivo. WOX1 blocked the prosurvival CREB-, CRE-, and AP-1-mediated promoter activation in vitro. In contrast, WOX1 enhanced promoter activation governed by c-Jun, Elk-1 and NF-kappaB. WOX1 directly activated NF-kappaB-regulated promoter via its WW domains. Smad4 and p53 were not involved in the delayed loss of small DRG neurons.

CONCLUSIONS/SIGNIFICANCE

Rapid activation of JNK1 and WOX1 during the acute phase of injury is critical in determining neuronal survival or death, as both proteins functionally antagonize. In the chronic phase, concurrent activation of WOX1, CREB, and NF-kappaB occurs in small neurons just prior to apoptosis. Likely in vivo interactions are: 1) WOX1 inhibits the neuroprotective CREB, which leads to eventual neuronal death, and 2) WOX1 enhances NF-kappaB promoter activation (which turns to be proapoptotic). Evidently, WOX1 is the potential target for drug intervention in mitigating symptoms associated with neuronal injury.

JNK1, a potential therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. Despite tremendous efforts to diagnose and institute new treatment regimens, the prognosis is still extremely poor. Therefore, knowledge of the molecular mechanisms governing the initiation, maintenance and progression of HCC is urgently needed. Recently, several groups have attributed an important role for c-Jun N-terminal kinase 1 (JNK1) in the pathogenesis of human HCC and its close association with the expression of HCC signature genes. In this review the various associations between JNK1 and HCC are discussed with the hope that targeting this pivotal kinase may lead to novel therapeutic approaches for this fatal disease.

Glycogen synthase kinase-3 inhibitors augment TRAIL-induced apoptotic death in human hepatoma cells

Hepatocellular carcinoma (HCC) displays a striking resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Therefore, the characterization of pharmacological agents that overcome this resistance may provide new therapeutic modalities for HCC. Here, we examined whether glycogen synthase kinase-3 (GSK-3) inhibitors could restore TRAIL sensitivity in hepatoma cells. To this aim, the effects of two GSK-3 inhibitors, lithium and SB-415286, were analyzed on TRAIL apoptotic signaling in human hepatoma cell lines in comparison with normal hepatocytes. We observed that both inhibitors sensitized hepatoma cells, but not normal hepatocytes, to TRAIL-induced apoptosis by enhancing caspase-8 activity and the downstream recruitment of the mitochondrial machinery. GSK-3 inhibitors also stabilized p53 and the down-regulation of p53 by RNA interference abolished the sensitizing effect of lithium on caspase-3 activation. Concomitantly, GSK-3 inhibitors strongly activated c-Jun N-terminal kinases (JNKs). The pharmacological inhibition of JNKs with AS601245 or SP600125 resulted in an earlier and stronger induction of apoptosis indicating that activated JNKs transduced protective signals and provided an anti-apoptotic balance to the pro-apoptotic effects of GSK-3 inhibitors. These findings demonstrate that GSK-3 exerts a negative and complex constraint on TRAIL apoptotic signaling in hepatoma cells, which can be greatly alleviated by GSK-3 inhibitors. Therefore, GSK-3 inhibitors may open new perspectives to enhance the anti-tumor activity of TRAIL in HCC.