ANXA8 down-regulation by EGF-FOXO4 signaling is involved in cell scattering and tumor metastasis of cholangiocarcinoma

The effect of TFAP2A/ANXA8 axis on ferroptosis of cervical squamous cell carcinoma (CESC) in vitro

Potential role and associated mechanisms of Annexin A8 (ANXA8), a member of the Annexins family, in cervical squamous cell carcinoma (CESC) are still unclear, despite being upregulated in various malignant tumors. Here, we observed a notably elevated expression of ANXA8 in CESC cells. The inhibition of ANXA8 amplified the susceptibility of CESC cells to Erastin and sorafenib-induced ferroptosis, whereas it exerted minimal influence on DPI7 and DPI10-induced ferroptosis. The results from the Fe2+ concentration assay showed no significant correlation between ANXA8 gene knockdown and intracellular Fe2+ concentration induced by ferroptosis inducers. Western blot analysis demonstrated that the knockdown of ANXA8 did not alter ACSL4 and LPCAT levels under ferroptosis-inducing conditions, but it did result in a reduction in intracellular GSH levels induced by the ferroptosis inducer. Subsequently, we identified TFAP2A as an upstream transcription factor of ANXA8, which plays a role in regulating cell ferroptosis. The knockdown of TFAP2A significantly elevated MDA levels and depressed GSH levels in the presence of a ferroptosis inducer, thereby inhibiting cell ferroptosis. However, this inhibitory effect could be reversed by ANXA8 overexpression. Therefore, our research suggests that the TFAP2A/ANXA8 axis exerts regulatory control over ferroptosis in CESC cells by mediating GSH synthesis in System Xc.

Labeled-free quantitative proteomic analysis of cervical squamous cell carcinoma identifies potential protein biomarkers

Background

Cervical cancer remains a prevalent cancer among women, and reliance on surgical and radio-chemical therapies can irreversibly affect patients' life span and quality of life. Thus, early diagnosis and further exploration into the pathogenesis of cervical cancer are crucial. Mass spectrometry technology is widely applied in clinical practice and can be used to further investigate the protein alterations during the onset of cervical cancer.

Methods

Employing labeled-free quantitative proteomics technology and bioinformatics tools, we analyzed and compared the differential protein expression profiles between normal cervical squamous cell tissues and cervical squamous cell cancer tissues. GEPIA is an online website for analyzing the RNA sequencing expression data of tumor and normal tissue data from the TCGA and the GTEx databases. This approach aided in identifying qualitative and quantitative changes in key proteins related to the progression of cervical cancer.

Results

Compared to normal samples, a total of 562 differentially expressed proteins were identified in cervical cancer samples, including 340 up-regulated and 222 down-regulated proteins. Gene ontology functional annotation, and KEGG pathway, and enrichment analysis revealed that the differentially expressed proteins mainly participated in metabolic pathways, spliceosomes, regulation of the actin cytoskeleton, and focal adhesion signaling pathways. Specifically, desmoplakin (DSP), protein phosphatase 1, regulatory (inhibitor) subunit 13 like (PPP1R13L) and ANXA8 may be involved in cervical tumorigenesis by inhibiting apoptotic signal transmission. Moreover, we used GEPIA database to validate the expression of DSP, PPP1R13L and ANXA8 in human cancers and normal cervix.

Conclusion

In this study, we identified 562 differentially expressed proteins, and there were three proteins expressed higher in the cervical cancer tissues. The functions and signaling pathways of these differentially expressed proteins lay a theoretical foundation for elucidating the molecular mechanisms of cervical cancer.

Forkhead box O proteins: steering the course of stem cell fate

Stem cells are pivotal players in the intricate dance of embryonic development, tissue maintenance, and regeneration. Their behavior is delicately balanced between maintaining their pluripotency and differentiating as needed. Disruptions in this balance can lead to a spectrum of diseases, underscoring the importance of unraveling the complex molecular mechanisms that govern stem cell fate. Forkhead box O (FOXO) proteins, a family of transcription factors, are at the heart of this intricate regulation, influencing a myriad of cellular processes such as survival, metabolism, and DNA repair. Their multifaceted role in steering the destiny of stem cells is evident, as they wield influence over self-renewal, quiescence, and lineage-specific differentiation in both embryonic and adult stem cells. This review delves into the structural and regulatory intricacies of FOXO transcription factors, shedding light on their pivotal roles in shaping the fate of stem cells. By providing insights into the specific functions of FOXO in determining stem cell fate, this review aims to pave the way for targeted interventions that could modulate stem cell behavior and potentially revolutionize the treatment and prevention of diseases.

Potential prognostic and therapeutic value of ANXA8 in renal cell carcinoma: based on the comprehensive analysis of annexins family

BACKGROUND

Annexins are a family of proteins involved in a wide variety of cellular processes such as inflammation, proliferation, differentiation, apoptosis, migration and membrane repair. However, the role of most Annexins in renal cell carcinoma (RCC) remained unclear.

METHODS

The differentially expressed Annexins in RCC compared with normal controls were screened applying the TCGA database. The correlation of differentially expressed Annexins with clinical stages, grades and overall survival was analyzed to explore the clinical significance of Annexins in RCC. Then ANXA8 was selected and further stained in the discover and validation RCC cohort. The correlation of ANXA8 expression with clinical parameter was verified at the protein level. To explore the potential function of ANXA8, ANXA8 was knockdown in the RCC cell line and further analyzed using transcriptome and bioinformatic analysis.

RESULTS

mRNA expression of ANXA1, ANXA2R, ANXA4, ANXA8, ANXA8L1 and ANXA13 were significantly upregulated in RCC compared with normal kidney tissues. In contrast, ANXA3 and ANXA9 mRNA expression was significantly downregulated. Higher expression of ANXA2R, ANXA8 and ANXA8L1 were correlated with worse overall survival, while lower expression of ANXA3, ANXA9 and ANXA13 were associated with worse clinical outcomes in RCC patients. We further demonstrated that ANXA8 expression was significantly increased in RCC compared with normal renal tissues at the protein level. And higher protein expression of ANXA8 was associated with higher clinical grades. Through the bioinformatics analysis and cell cycle analysis, we found knockdown of ANXA8 mainly influenced the cell cycle and DNA replication. The top ten hub genes consist of CDC6, CDK2, CHEK1, CCNB1, ORC1, CHEK2, MCM7, CDK1, PCNA and MCM3.

CONCLUSIONS

Multiple members of Annexins were abnormally expressed and associated with the prognosis of RCC. The expression of ANXA8 was significantly increased in RCC and associated with poor prognosis. ANXA8 might influence the cell cycle and could be a potential biomarker and therapeutic target for RCC.

Primary Liver Cancers: Connecting the Dots of Cellular Studies and Epidemiology with Metabolomics

Liver cancers are rising worldwide. Between molecular and epidemiological studies, a research gap has emerged which might be amenable to the technique of metabolomics. This review investigates the current understanding of liver cancer's trends, etiology and its correlates with existing literature for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA) and hepatoblastoma (HB). Among additional factors, the literature reports dysfunction in the tricarboxylic acid metabolism, primarily for HB and HCC, and point mutations and signaling for CCA. All cases require further investigation of upstream and downstream events. All liver cancers reported dysfunction in the WNT/β-catenin and P13K/AKT/mTOR pathways as well as changes in FGFR. Metabolites of IHD1, IDH2, miRNA, purine, Q10, lipids, phosphatidylcholine, phosphatidylethanolamine, acylcarnitine, 2-HG and propionyl-CoA emerged as crucial and there was an attempt to elucidate the WNT/β-catenin and P13K/AKT/mTOR pathways metabolomically.

The molecular mechanisms and targeting strategies of transcription factors in cholangiocarcinoma

INTRODUCTION

Cholangiocarcinoma consists of a cluster of malignant biliary tumors that tend to have a poor prognosis, ranking as the second most prevalent type of liver cancer, and their incidence rate has increased globally recently. The high-frequency driving mutations of cholangiocarcinoma, such as KRAS/IDH1/ARID1A/P53, imply the epigenetic instability of cholangiocarcinoma, leading to the dysregulation of various related transcription factors, thus affecting the occurrence and development of cholangiocarcinoma. Increasingly evidence indicates that the high heterogeneity and malignancy of cholangiocarcinoma are closely related to the dysregulation of transcription factors which promote cell proliferation, invasion, migration, angiogenesis, and drug resistance through reprogrammed transcriptional networks. It is of great significance to further explore and summarize the role of transcription factors in cholangiocarcinoma.

AREAS COVERED

This review summarizes the oncogenic or tumor suppressive roles of key transcription factors in regulating cholangiocarcinoma progression and the potential targeting strategies of transcription factors in cholangiocarcinoma.

EXPERT OPINION

Cholangiocarcinoma is a type of cancer highly influenced by transcriptional regulation, specifically transcription factors and epigenetic regulatory factors. Targeting transcription factors could be a potential and important strategy that is likely to impact future cholangiocarcinoma treatment.

Clinical diagnosis and treatment strategies for sarcomatoid intrahepatic cholangiocarcinoma

Sarcomatoid intrahepatic cholangiocarcinoma (SiCCA) is a malignant tumor composed of mixed epithelial cells and mesenchymal cells derived from malignant bile duct cells. SiCCA has a low incidence and has no specific clinical manifestations and serological and imaging examinations. The diagnosis of SiCCA relies on histopathology and immunohistochemistry. The very high malignancy of SiCCA makes it prone to liver and other organ metastases. SiCCA has a poor prognosis because it has a low surgical resection rate, is easy to relapse shortly after surgery, and has no effective prevention and treatment measures. Comprehensive analysis integrating imaging, serum tumor markers, and histopathological examination technology is an important measure to improve the diagnosis of SiCCA and reduce the misdiagnosis rate. Early diagnosis, surgical treatment, and comprehensive postoperative treatment based on chemotherapy are the keys to improving the survival and prognosis of patients with SiCCA.

SNPs in miRNAs and Target Sequences: Role in Cancer and Diabetes

miRNAs are fascinating molecular players for gene regulation as individual miRNA can control multiple targets and a single target can be regulated by multiple miRNAs. Loss of miRNA regulated gene expression is often reported to be implicated in various human diseases like diabetes and cancer. Recently, geneticists across the world started reporting single nucleotide polymorphism (SNPs) in seed sequences of miRNAs. Similarly, SNPs are also reported in various target sequences of these miRNAs. Both the scenarios lead to dysregulated gene expression which may result in the progression of diseases. In the present paper, we explore SNPs in various miRNAs and their target sequences reported in various human cancers as well as diabetes. Similarly, we also present evidence of these mutations in various other human diseases.

FOXO4 Inhibits the Migration and Metastasis of Colorectal Cancer by Regulating the APC2/β-Catenin Axis

Objective: Adenomatous polyposis coli 2 (APC2) is a colorectal cancer (CRC) tumor-suppressor gene. The progression of several kinds of cancer is closely associated with Forkhead box O4 (FOXO4). However, the function of FOXO4 in CRC is unclear. This study focused on the role of FOXO4 and the relationship between FOXO4 and APC2 in CRC migration and metastasis.

Methods: The expressions of FOXO4, APC2, and p(S37)-β-catenin were detected in CRC tissues by immunohistochemistry, and their correlation was analyzed using the Spearman coefficient. Chromatin immunoprecipitation was used to test whether FOXO4 binds and regulates APC2 as a transcription factor. Either FOXO4 overexpression or APC2 knockdown was performed in CRC cell lines. The roles of FOXO4 and APC2 were investigated in CRC migration and metastasis.

Results: FOXO4 was downregulated in CRC tissues compared with normal tissues and positively correlated with APC2 and p(S37)-β-catenin. FOXO4 could combine the promoter region of APC2 to upregulate its expression and increase the phosphorylated degradation of β-catenin. Stemness genes (CD133, ABCG1, and SOX2) were inhibited by FOXO4 overexpression in SW620 and HCT116 cell lines. Overexpressed FOXO4 suppressed epithelial–mesenchymal transition and the migration of CRC cell lines and metastasis of HCT116 in both the spleen and liver of nude mice, which was reversed by APC2 knockdown.

Conclusion: This research demonstrates that overexpressed FOXO4 inhibits the migration and metastasis of CRC cells by enhancing the APC2/β-catenin axis, suggesting that FOXO4 is a potential therapeutic target of CRC.

Annexin A8 regulated by lncRNA-TUG1/miR-140-3p axis promotes bladder cancer progression and metastasis

Bladder cancer is the ninth most diagnosed cancer in the world. This study aims to investigate the role and mechanisms of the taurine-upregulated gene 1 (TUG1)/miR-140-3p/annexin A8 (ANXA8) axis in bladder cancer. Western blotting and qRT-PCR determined the expression levels of ANXA8, miR-140-3p, TUG1, and epithelial-mesenchymal transition (EMT) markers. RNA immunoprecipitation (RIP), luciferase assay, and RNA pull-down assay validated the association among ANXA8, miR-140-3p, and TUG1. The biological functions were determined by colony formation, Annexin V-fluorescein isothiocyanate (FITC)/propidium (PI) staining, and transwell assays. Xenograft tumorigenesis detected tumor growth and metastasis in vivo. Pathological analysis was examined by hematoxylin and eosin (H&E) and immunohistochemistry (IHC) analyses. ANXA8 was elevated in bladder tumors and cells. Knockdown of ANXA8 suppressed cell growth, migration, invasion, and EMT in UMUC-3 and T24 cells. ANXA8 was determined as a miR-140-3p target gene. Overexpression of miR-140-3p suppressed cell proliferation, migration, invasion, and EMT via targeting ANXA8. TUG1 promoted ANXA8 expression via sponging miR-140-3p. Silencing of miR-140-3p or ANXA8 overexpression abrogated the tumor-suppressive effects of TUG1 silencing on bladder cancer cell growth and metastasis. The TUG1/miR-140-3p/ANXA8 axis was also implicated in tumor growth and lung metastasis in vivo. TUG1 promotes bladder cancer progression and metastasis through activating ANXA8 by sponging miR-140-3p, which sheds light on the mechanisms of bladder cancer pathogenesis.

Role of Forkhead Box O Proteins in Hepatocellular Carcinoma Biology and Progression (Review)

Hepatocellular carcinoma (HCC), the most common type of malignant tumor of the digestive system, is associated with high morbidity and mortality. The main treatment for HCC is surgical resection. Advanced disease, recurrence, and metastasis are the main factors affecting prognosis. Chemotherapy and radiotherapy are not sufficiently efficacious for the treatment of primary and metastatic HCC; therefore, optimizing targeted therapy is essential for improving outcomes. Forkhead box O (FOXO) proteins are widely expressed in cells and function to integrate a variety of growth factors, oxidative stress signals, and other stimulatory signals, thereby inducing the specific expression of downstream signal factors and regulation of the cell cycle, senescence, apoptosis, oxidative stress, HCC development, and chemotherapy sensitivity. Accordingly, FOXO proteins are considered multifunctional targets of cancer treatment. The current review discusses the roles of FOXO proteins, particularly FOXO1, FOXO3, FOXO4, and FOXO6, in HCC and establishes a theoretical basis for the potential targeted therapy of HCC.

jouvence, a new human snoRNA involved in the control of cell proliferation

Background

Small nucleolar RNAs (snoRNAs) are non-coding RNAs that are conserved from archaebacteria to mammals. They are associated in the nucleolus, with proteins to form small nucleolar ribonucleoprotein (snoRNPs). They modify ribosomal RNAs, for example, the H/ACA box that converts uridine to pseudouridine. In humans, various pathologies have been associated with snoRNAs, and several snoRNAs have been reported to participate in many cancer processes. Recently, a new H/ACA box snoRNA named jouvence has been identified in Drosophila and has been shown to be involved in lifespan determination in relation to gut homeostasis. Because snoRNAs are conserved through evolution, both structurally and functionally, a jouvence orthologue has been identified in humans. RT-PCR has revealed that jouvence is expressed, suggesting that it might be functional. These results suggest the hypothesis that jouvence may display similar functions, including increasing the healthy lifespan in humans.

Results

Here, we report the characterization of the human snoRNA jouvence, which has not yet been annotated in the genome. We show that its overexpression significantly stimulates cell proliferation, both in various stable cancerous cell lines as well as in primary cells. By contrast, its knockdown by siRNA leads to the opposite phenotype, a rapid decrease in cell proliferation. Transcriptomic analysis (RNA-Seq) revealed that the overexpression of jouvence leads to a dedifferentiation signature of the cells. Conversely, the knockdown of jouvence led to a striking decrease in the expression levels of genes involved in ribosome biogenesis and the spliceosome.

Conclusion

The overexpression of a single and short non-coding RNA of 159 nucleotides, the snoRNA-jouvence, seems to be sufficient to reorient cells toward stemness, while its depletion blocks cell proliferation. In this context, we speculate that the overexpression of jouvence, which appears to be a non-canonical H/ACA snoRNA, could represent a new tool to fight against the deleterious effects of aging, while inversely, its knockdown by siRNA could represent a new approach in cancer therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-020-07197-3.

FOXO transcription factor family in cancer and metastasis

Forkhead box O (FOXO) transcription factors regulate diverse biological processes, affecting development, metabolism, stem cell maintenance and longevity. They have also been increasingly recognised as tumour suppressors through their ability to regulate genes essential for cell proliferation, cell death, senescence, angiogenesis, cell migration and metastasis. Mechanistically, FOXO proteins serve as key connection points to allow diverse proliferative, nutrient and stress signals to converge and integrate with distinct gene networks to control cell fate, metabolism and cancer development. In consequence, deregulation of FOXO expression and function can promote genetic disorders, metabolic diseases, deregulated ageing and cancer. Metastasis is the process by which cancer cells spread from the primary tumour often via the bloodstream or the lymphatic system and is the major cause of cancer death. The regulation and deregulation of FOXO transcription factors occur predominantly at the post-transcriptional and post-translational levels mediated by regulatory non-coding RNAs, their interactions with other protein partners and co-factors and a combination of post-translational modifications (PTMs), including phosphorylation, acetylation, methylation and ubiquitination. This review discusses the role and regulation of FOXO proteins in tumour initiation and progression, with a particular emphasis on cancer metastasis. An understanding of how signalling networks integrate with the FOXO transcription factors to modulate their developmental, metabolic and tumour-suppressive functions in normal tissues and in cancer will offer a new perspective on tumorigenesis and metastasis, and open up therapeutic opportunities for malignant diseases.

Emerging Cancer Epigenetic Mechanisms Regulated by All-Trans Retinoic Acid

All-trans retinoic acid (RA), which is the dietary bioactive derivative obtained from animal (retinol) and plant sources (beta-carotene), is a physiological lipid signal of both embryonic and postembryonic development. During pregnancy, either RA deficiency or an excessive RA intake is teratogenic. Too low or too high RA affects not only prenatal, but also postnatal, developmental processes such as myelopoiesis and mammary gland morphogenesis. In this review, we mostly focus on emerging RA-regulated epigenetic mechanisms involving RA receptor alpha (RARA) and Annexin A8 (ANXA8), which is a member of the Annexin family, as well as ANXA8 regulatory microRNAs (miRNAs). The first cancer showing ANXA8 upregulation was reported in acute promyelocytic leukemia (APL), which induces the differentiation arrest of promyelocytes due to defective RA signaling caused by RARA fusion genes as the PML-RARA gene. Over the years, ANXA8 has also been found to be upregulated in other cancers, even in the absence of RARA fusion genes. Mechanistic studies on human mammary cells and mammary glands of mice showed that ANXA8 upregulation is caused by genetic mutations affecting RARA functions. Although not all of the underlying mechanisms of ANXA8 upregulation have been elucidated, the interdependence of RA-RARA and ANXA8 seems to play a relevant role in some normal and tumorigenic settings.

Prognostic Value of ANXA8 in Gastric Carcinoma

Gastric carcinoma (GC) remains one of the most common and deadly cancers worldwide. In China, the incidence and mortality rates related to GC were quite high. Annexin A8 (ANXA8) is a member of the annexins family of calcium-dependent membrane phospholipid binding proteins. According to recent research, the up-regulation of ANXA8 is closely associated with various types of tumors. However, the specific role of ANXA8 in GC remains unclear. In our study, we explored the prognostic value of ANXA8 in GC. Here, with the data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets (GSE19826 and GSE13861) analyzed, we further performed quantitative real-time polymerase chain reaction (qRT-PCR) using 58 pairs of fresh-frozen tissues. We also subjected 152 pairs of formalin-fixed, paraffin-embedded GC tumor tissues from patients, and the adjacent normal gastric tissues (ANGTs) to immunohistochemical (IHC) analysis. Hence, we found an elevated expression of ANXA8 in tumor tissues with bioinformatics analyses, qRT-PCR, western blot and IHC. Over-expression of ANXA8 was strongly correlated with TNM stages and differentiation grades. Kaplan-Meier and cox proportional-hazard analyses showed that the increased expression of ANXA8 was strongly associated with overall survival (OS) and disease-free survival (DFS) in GC patients. Moreover, we found that ANXA8 is an independent prognostic factor of GC patients' OS and DFS. In brief, those results suggest that ANXA8 can act as an oncogene of GC development and can serve as a potential prognostic biomarker for GC treatment.

Differences in the early stage gene expression profiles of lung adenocarcinoma and lung squamous cell carcinoma

The discovery of lung carcinoma subtype-specific gene expression changes has the potential to elucidate the molecular differences and provide personalized therapeutic targets for these pathologies. The aim of the present study was to characterize the genetic profiles of the early stages (IA/IB) of two non-small cell lung cancer subtypes, adenocarcinoma (AD) and squamous cell carcinoma (SC). RNA-Seq gene expression data from The Cancer Genome Atlas was analyzed to compare the gene expression differences between AD and SC. The gene sets specific to each subtype were further analyzed to identify the enriched Gene Ontology terms, Kyoto Encyclopedia of Genes and Genomes pathways and biological functions. The results demonstrated that a unique set of genes (145 upregulated and 27 downregulated) was altered in AD, but not in SC; another set of genes (146 upregulated and 103 downregulated) was significantly altered in SC, but not in AD. Genes highly upregulated specifically in AD included albumin (1,732-fold), protein lin-28 homolog A, which is a positive regulator of cyclin-dependent kinase 2 (150-fold) and gastric lipase (81-fold). Genes highly upregulated specifically in SC included amelotin (618-fold), alcohol dehydrogenase 7 (57-fold), aclerosteosis (55-fold) and claudin-22 (54-fold). Several cancer/testis antigen family genes were notably upregulated in SC, but not in AD, whereas mucins were upregulated only in AD. Functional pathway analysis demonstrated that the dysregulation of genes associated with retinoid X receptors was common in AD and SC, genes associated with ‘lipid metabolism’ and ‘drug metabolism’ were dysregulated only in SC, whereas genes associated with ‘molecular transport’ and ‘cellular growth and proliferation’ were significantly enriched in AD specifically. These results reveal fundamental differences in the gene expression profiles of early-stage AD and SC. In addition, the present study identified molecular pathways that are uniquely associated with the pathogenesis of these subtypes.

Annexin A8 can serve as potential prognostic biomarker and therapeutic target for ovarian cancer: based on the comprehensive analysis of Annexins

BACKGROUND

Annexins are involved in vesicle trafficking, cell proliferation and apoptosis, but their functional mechanisms in ovarian cancer remain unclear. In this study, we analyzed Annexins in ovarian cancer using different databases and selected Annexin A8 (ANXA8), which showed the greatest prognostic value, for subsequent validation in immunohistochemical (IHC) assays.

METHODS

The mRNA expression levels, genetic variations, prognostic values and gene-gene interaction network of Annexins in ovarian cancer were analyzed using the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, Kaplan-Meier plotter and GeneMANIA database. ANXA8 was selected for analyzing the biological functions and pathways of its co-expressed genes, and its correlation with immune system responses via the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and the TISIDB database, respectively. We validated the expression of ANXA8 in ovarian cancer via IHC assays and analyzed its correlation with clinicopathological parameters and prognosis.

RESULTS

ANXA2/3/8/11 mRNA expression levels were significantly upregulated in ovarian cancer, and ANXA5/6/7 mRNA expression levels were significantly downregulated. Prognostic analysis suggested that significant correlations occurred between ANXA2/4/8/9 mRNA upregulation and poor overall survival, and between ANXA8/9/11 mRNA upregulation and poor progression-free survival in patients with ovarian serous tumors. Taken together, results suggested that ANXA8 was most closely associated with ovarian cancer tumorigenesis and progression. Further analyses indicated that ANXA8 may be involved in cell migration, cell adhesion, and vasculature development, as well as in the regulation of PI3K-Akt, focal adhesion, and proteoglycans. Additionally, ANXA8 expression was significantly correlated with lymphocytes and immunomodulators. The IHC results showed that ANXA8 expression was higher in the malignant tumor group than in the borderline and benign tumor groups and normal ovary group, and high ANXA8 expression was an independent risk factor for survival and prognosis of ovarian cancer patients (P = 0.013).

CONCLUSIONS

Members of the Annexin family display varying degrees of abnormal expressions in ovarian cancer. ANXA8 was significantly highly expressed in ovarian cancer, and high ANXA8 expression was significantly correlated with poor prognosis. Therefore, ANXA8 is a high candidate as a novel biomarker and therapeutic target for ovarian cancer.

Inhibition of Brd4 alleviates renal ischemia/reperfusion injury-induced apoptosis and endoplasmic reticulum stress by blocking FoxO4-mediated oxidative stress

Ischemia/reperfusion injury (I/R) is one of the leading causes of acute kidney injury (AKI) that typically occurs in renal surgeries. However, renal I/R still currently lacks effective therapeutic targets. In this study, we proved that inhibition of Brd4 with its selective inhibitor, JQ1, could exert a protective role in renal I/R injury in mice. Inhibiting Brd4 with either JQ1 or genetic knockdown resulted in reduction of endoplasmic reticulum stress (ERS)-associated protein and proapoptotic protein expression both in I/R-induced injury and hypoxia/reoxygenation (H/R) stimulation in HK-2 cells. H/R-induced apoptosis and ERS depended on oxidative stress in vitro. Moreover, FoxO4, which is involved in the generation of hydrogen peroxide, was up-regulated during H/R stimulation-mediated apoptosis and ERS, and this upregulation could be abolished by Brd4 inhibition. Consistently, FoxO4-mediated ROS generation was attenuated upon inhibition of Brd4 with JQ1 or siRNA against Brd4. Further, the transcriptional activity of FoxO4 was suppressed by PI3K and AKT phosphorylation, which are upstream signals of FoxO4 expression, and were enhanced by Brd4 both in vivo and in vitro. In conclusion, our results proved that Brd4 inhibition blocked renal apoptotic and ERS protein expression by preventing FoxO4-dependent ROS generation through the PI3K/AKT pathway, indicating that Brd4 could be a potential therapeutic target for renal I/R injury.

•

Brd4 was up-regulated in renal I/R injury.

•

Brd4 inhibitor JQ1 alleviated renal I/R injury.

•

Brd4 inhibition blocked H/R-induced oxidative stress, apoptosis and ERS through FoxO4.

•

Brd4 regulated FoxO4 through the PI3K/AKT pathway.

Annexin A8 (ANXA8) regulates proliferation of porcine endometrial cells via Akt signalling pathway

Annexin A8 (ANXA8) gene, a member of the annexin family, encodes an anticoagulant protein involved in blood coagulation cascade and acts as an indirect inhibitor of the thromboplastin-specific complex. However, little is known about the function of ANXA8 in porcine endometrial cells so far. Here, ANXA8 mRNA was found to be abundant in porcine endometrium on days 11-13 of pregnancy. Real-time RT-PCR analysis indicated that the mRNA expression of the leukaemia inhibitory factor (LIF) and the epidermal growth factor (EGF) was upregulated by ANXA8 in porcine endometrial cells. Immunofluorescence technology and cell cycle analysis revealed that ANXA8 promoted the proliferation of endometrial cells, as evidenced by the abundant proliferating cell nuclear antigen (PCNA) expression and an increase in the S phase. Western blot analysis results indicated that ANXA8 activated the phosphorylation of the target protein kinase B (Akt) protein. Immunofluorescence technology results showed that the PCNA protein had no significant change in porcine endometrial cells with both ANXA8 overexpression and the addition of Akt inhibitor. Furthermore, the number of implantation sites was significantly reduced by injection of mus-siRNA-ANXA8 into the uterine horn of mice. Collectively, these results suggest that ANXA8 promotes the proliferation of endometrial cells through the Akt signalling pathway.

Forkhead box O4 transcription factor in human neoplasms: Cannot afford to lose the novel suppressor

Forkhead box O4 (FOXO4), a member of FOXO family, has been highlighted as an essential transcriptional regulator in many diverse carcinomas. Accumulated studies have demonstrated that FOXO4 is downregulated and associated with tumorigenesis, invasiveness, and metastasis of most human cancer. FOXO4 alteration is also closely linked to the prognosis of various types of cancer. The aim of this review is to comprehensively present the clinical and pathological significance of FOXO4 in human cancer. Additionally, the potential clinical applications of future FOXO4 research are discussed. Collectively, the information reviewed here should increase the potential of FOXO4 as a therapeutic target for cancer.

Stochastic phenotype switching leads to intratumor heterogeneity in human liver cancer

Intratumor heterogeneity is increasingly recognized as a major factor impacting diagnosis and personalized treatment of cancer. We characterized stochastic phenotype switching as a mechanism contributing to intratumor heterogeneity and malignant potential of liver cancer. Clonal analysis of primary tumor cell cultures of a human sarcomatoid cholangiocarcinoma identified different types of self-propagating subclones characterized by stable (keratin-7-positive or keratin-7-negative) phenotypes and an unstable phenotype consisting of mixtures of keratin-7-positive and keratin-7-negative cells, which lack stem cell features but may reversibly switch their phenotypes. Transcriptome sequencing and immunohistochemical studies with the markers Zeb1 and CD146/MCAM demonstrated that switching between phenotypes is linked to changes in gene expression related but not identical to epithelial-mesenchymal transition. Stochastic phenotype switching occurred during mitosis and did not correlate with changes in DNA methylation. Xenotransplantation assays with different cellular subclones demonstrated increased tumorigenicity of cells showing phenotype switching, resulting in tumors morphologically resembling the invasive component of primary tumor and metastasis.

CONCLUSION

Our data demonstrate that stochastic phenotype switching contributes to intratumor heterogeneity and that cells with a switching phenotype have increased malignant potential. (Hepatology 2017).

Molecular Mechanisms Driving Cholangiocarcinoma Invasiveness: An Overview

The acquisition of invasive functions by tumor cells is a first and crucial step toward the development of metastasis, which nowadays represents the main cause of cancer-related death. Cholangiocarcinoma (CCA), a primary liver cancer originating from the biliary epithelium, typically develops intrahepatic or lymph node metastases at early stages, thus preventing the majority of patients from undergoing curative treatments, consistent with their very poor prognosis. As in most carcinomas, CCA cells gradually adopt a motile, mesenchymal-like phenotype, enabling them to cross the basement membrane, detach from the primary tumor, and invade the surrounding stroma. Unfortunately, little is known about the molecular mechanisms that synergistically orchestrate this proinvasive phenotypic switch. Autocrine and paracrine signals (cyto/chemokines, growth factors, and morphogens) permeating the tumor microenvironment undoubtedly play a prominent role in this context. Moreover, a number of recently identified signaling systems are currently drawing attention as putative mechanistic determinants of CCA cell invasion. They encompass transcription factors, protein kinases and phosphatases, ubiquitin ligases, adaptor proteins, and miRNAs, whose aberrant expression may result from either stochastic mutations or the abnormal activation of upstream pro-oncogenic pathways. Herein we sought to summarize the most relevant molecules in this field and to discuss their mechanism of action and potential prognostic relevance in CCA. Hopefully, a deeper knowledge of the molecular determinants of CCA invasiveness will help to identify clinically useful biomarkers and novel druggable targets, with the ultimate goal to develop innovative approaches to the management of this devastating malignancy.

Forkhead box O proteins: Crucial regulators of cancer EMT

The epithelial-mesenchymal transition (EMT) is an acknowledged cellular transition process in which epithelial cells acquire mesenchymal-like properties that endow cancer cells with increased migratory and invasive behavior. Forkhead box O (FOXO) proteins have been shown to orchestrate multiple EMT-associated pathways and EMT-related transcription factors (EMT-TFs), thereby modulating the EMT process. The focus of the current review is to evaluate the latest research progress regarding the roles of FOXO proteins in cancer EMT. First, a brief overview of the EMT process in cancer and a general background on the FOXO family are provided. Next, we present the interactions between FOXO proteins and multiple EMT-associated pathways during malignancy development. Finally, we propose several novel potential directions for future research. Collectively, the information compiled herein should serve as a comprehensive repository of information on this topic and should aid in the design of additional studies and the future development of FOXO proteins as therapeutic targets.

Role of Forkhead Box Class O proteins in cancer progression and metastasis

It is now widely accepted that several gene alterations including transcription factors are critically involved in cancer progression and metastasis. Forkhead Box Class O proteins (FoxOs) including FoxO1/FKHR, FoxO3/FKHRL1, FoxO4/AFX and FoxO6 transcription factors are known to play key roles in proliferation, apoptosis, metastasis, cell metabolism, aging and cancer biology through their phosphorylation, ubiquitination, acetylation and methylation. Though FoxOs are proved to be mainly regulated by upstream phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3 K)/Akt signaling pathway, the role of FoxOs in cancer progression and metastasis still remains unclear so far. Thus, with previous experimental evidences, the present review discussed the role of FoxOs in association with metastasis related molecules including cannabinoid receptor 1 (CNR1), Cdc25A/Cdk2, Src, serum and glucocorticoid inducible kinases (SGKs), CXCR4, E-cadherin, annexin A8 (ANXA8), Zinc finger E-box-binding homeobox 2 (ZEB2), human epidermal growth factor receptor 2 (HER2) and mRNAs such as miR-182, miR-135b, miR-499-5p, miR-1274a, miR-150, miR-34b/c and miR-622, subsequently analyzed the molecular mechanism of some natural compounds targeting FoxOs and finally suggested future research directions in cancer progression and metastasis.

Epithelial-mesenchymal transition in cholangiocarcinoma: From clinical evidence to regulatory networks

Cholangiocarcinoma (CCA) is an aggressive tumor with a poor prognosis due to its late clinical presentation and the lack of effective non-surgical therapies. Unfortunately, most of the patients are not eligible for curative surgery owing to the presence of metastases at the time of diagnosis. Therefore, it is important to understand the steps leading to cell dissemination in patients with CCA. To metastasize from the primary site, cancer cells must acquire migratory and invasive properties by a cell plasticity-promoting phenomenon known as epithelial-mesenchymal transition (EMT). EMT is a reversible dynamic process by which epithelial cells gradually adopt structural and functional characteristics of mesenchymal cells, and has lately become a centre of attention in the field of metastatic dissemination. In the present review, we aim to provide an extensive overview of the current clinical data and the prognostic value of different EMT markers that have been analysed in CCA. We summarize all the regulatory networks implicated in EMT from the membrane receptors to the main EMT-inducing transcription factors (SNAIL, TWIST and ZEB). Furthermore, since a tumor is a complex structure not exclusively formed by tumor cells, we also address the prominent role of the main cell types of the desmoplastic stroma that characterizes CCA in the regulation of EMT. Finally, we discuss the therapeutic considerations and difficulties faced to develop an effective anti-EMT treatment due to the redundancies and bypasses among the pathways regulating EMT.

Integrated molecular analysis reveals complex interactions between genomic and epigenomic alterations in esophageal adenocarcinomas

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the United States and Western countries. In this study, we carried out an integrative molecular analysis to identify interactions between genomic and epigenomic alterations in regulating gene expression networks in EAC. We detected significant alterations in DNA copy numbers (CN), gene expression levels, and DNA methylation profiles. The integrative analysis demonstrated that altered expression of 1,755 genes was associated with changes in CN or methylation. We found that expression alterations in 84 genes were associated with changes in both CN and methylation. These data suggest a strong interaction between genetic and epigenetic events to modulate gene expression in EAC. Of note, bioinformatics analysis detected a prominent K-RAS signature and predicted activation of several important transcription factor networks, including β-catenin, MYB, TWIST1, SOX7, GATA3 and GATA6. Notably, we detected hypomethylation and overexpression of several pro-inflammatory genes such as COX2, IL8 and IL23R, suggesting an important role of epigenetic regulation of these genes in the inflammatory cascade associated with EAC. In summary, this integrative analysis demonstrates a complex interaction between genetic and epigenetic mechanisms providing several novel insights for our understanding of molecular events in EAC.

MiR-150 promotes cellular metastasis in non-small cell lung cancer by targeting FOXO4

Previous studies have shown that dysregulation of microRNA-150 (miR-150) is associated with aberrant proliferation of human non-small cell lung cancer (NSCLC) cells. However, whether miR-150 has a critical role in NSCLC cell metastasis is unknown. Here, we reveal that the critical pro-metastatic role of miR-150 in the regulation of epithelial-mesenchymal-transition (EMT) through down-regulation of FOXO4 in NSCLC. In vitro, miR-150 targets 3'UTR region of FOXO4 mRNA, thereby negatively regulating its expression. Clinically, the expression of miR-150 was frequently up-regulated in metastatic NSCLC cell lines and clinical specimens. Contrarily, FOXO4 was frequently down-regulated in NSCLC cell lines and clinical specimens. Functional studies show that ectopic expression of miR-150 enhanced tumor cell metastasis in vitro and in a mouse xenograft model, and triggered EMT-like changes in NSCLC cells (including E-cadherin repression, N-cadherin and Vimentin induction, and mesenchymal morphology). Correspondingly, FOXO4 knockdown exhibited pro-metastatic and molecular effects resembling the effect of miR-150 over-expression. Moreover, NF-κB/snail/YY1/RKIP circuitry regulated by FOXO4 were likely involved in miR-150-induced EMT event. Simultaneous knockdown of miR-150 and FOXO4 abolished the phenotypic and molecular effects caused by individual knockdown of miR-150. Therefore, our study provides previously unidentified pro-metastatic roles and mechanisms of miR-150 in NSCLC.

C-terminal-truncated HBV X promotes hepato-oncogenesis through inhibition of tumor-suppressive β-catenin/BAMBI signaling

C-terminal-truncated hepatitis B virus (HBV) X (HBx) (ctHBX) is frequently detected in hepatocellular carcinoma (HCC) through HBV integration into the host genome. However, the molecular mechanisms underlying ctHBx-associated oncogenic signaling have not yet been clarified. To elucidate the biological role of ctHBx in hepato-oncogenesis, we functionally analyzed ctHBx-mediated regulation of the activin membrane-bound inhibitor bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) through transforming growth factor-β (TGF-β) or β-catenin (CTNNB1) in HCC cells and in an animal model, and we compared its role to that of the full-length HBx protein. Ectopic ctHBx expression generated more colonies in anchorage-dependent and -independent growth assays than did HBx expression alone. ctHBx downregulated BAMBI to a greater degree than did HBx in HCC cells. HBx activated the Wnt/β-catenin pathway, which positively regulated the BAMBI expression through T-cell factor 1 signaling, whereas ctHBx negatively regulated the Wnt/β-catenin pathway. BAMBI downregulated the β-catenin and TGF-β1 signaling pathways. TGF-β1 positively regulated BAMBI expression thorough Smad3 signaling. Furthermore, knockdown of BAMBI was more tumorigenic in HCC cells. Therefore, downregulation of both β-catenin and TGF-β1 signaling by BAMBI might contribute to tumor suppression in mice xenotransplanted with HepG2 or SH-J1 cells. Taken together, ctHBx may have a more oncogenic role than HBx through its inhibition of tumor-suppressive β-catenin/BAMBI signaling.

Low expression of the FoxO4 gene may contribute to the phenomenon of EMT in non-small cell lung cancer

Because of its importance in tumor invasion and metastasis, the epithelial-mesenchymal transition (EMT) has become a research focus in the field of cancer. Recently, evidence has been presented that FoxO4 might be involved in EMT. Our study aimed to detect the expression of FoxO4, E-cadherin and vimentin in non-small cell lung cancers (NSCLCs). We also investigated clinical features and their correlations with the markers. In our study, FoxO4, E-cadherin and vimentin were assessed by immunohistochemistry in a tissue microarray (TMA) containing 150 cases of NSCLC. In addition, the expression level of FoxO4 protein was determined by Western blotting. The percentages of FoxO4, E-cadherin and vimentin positive expression in NSCLCs were 42.7%, 38.7% and 55.3%, respectively. Immunoreactivity of FoxO4 was low in NSCLC when compared with paired normal lung tissues. There were significant correlations between FoxO4 and TNM stage (P<0.001), histological differentiation (P=0.004) and lymph node metastasis (P<0.001), but no significant links with age (P=0.323), gender (P=0.410), tumor size (P=0.084), smoking status (P=0.721) and histological type (P=0.281). Our study showed that low expression of FoxO4 correlated with decreased expression of E-cadherin and elevated expression of vimentin. Cox regression analysis indicated FoxO4 to be an independent prognostic factor in NSCLC (P=0.046). These data suggested that FoxO4 might inhibit the process of EMT in NSCLC, and might therefore be a target for therapy.

FBXW7 suppresses epithelial-mesenchymal transition, stemness and metastatic potential of cholangiocarcinoma cells

Epithelial-mesenchymal transition (EMT) plays a fundamental role in cancer metastasis. The ubiquitin ligase FBXW7, a general tumor suppressor in human cancer, has been implicated in diverse cellular processes, however, its role in cholangiocarcinoma (CCA) metastasis has not been identified. Here, we report a crucial role of FBXW7 in CCA metastasis by regulating EMT. Loss of FBXW7 expression was detected in CCA cells and clinical specimens. Clinicopathological analysis revealed a close correlation between FBXW7 deficiency and metastasis, TNM stage and differentiation in intrahepatic CCA and perihilar CCA. Moreover, FBXW7 silencing in CCA cells dramatically promoted EMT, stem-like capacity and metastasis both in vitro and in vivo. Conversely, FBXW7 overexpression attenuated these processes. Mechanistically, treatment with rapamycin, a mTOR inhibitor, inhibited EMT, stem-like capacity and metastasis induced by FBXW7 silencing both in vitro and in vivo. Furthermore, the expression of EMT regulating transcription factors, snail, slug and ZEB1, were also decreased markedly with rapamycin treatment. In addition, silencing ZEB1 inhibited EMT and metastasis of both CCA cells and FBXW7 deficient CCA cells, which implicated the potential role of ZEB1 in FBXW7/mTOR signaling pathway related CCA metastasis. In conclusion, our findings defined a pivotal function of FBXW7 in CCA metastasis by regulating EMT.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Epithelial-to-Mesenchymal Transition and Cancer Invasiveness: What Can We Learn from Cholangiocarcinoma?

In addition to its well-established role in embryo development, epithelial-to-mesenchymal transition (EMT) has been proposed as a general mechanism favoring tumor metastatization in several epithelial malignancies. Herein, we review the topic of EMT in cholangiocarcinoma (CCA), a primary liver cancer arising from the epithelial cells lining the bile ducts (cholangiocytes) and characterized by an abundant stromal reaction. CCA carries a dismal prognosis, owing to a pronounced invasiveness and scarce therapeutic opportunities. In CCA, several reports indicate that cancer cells acquire a number of EMT biomarkers and functions. These phenotypic changes are likely induced by both autocrine and paracrine signals released in the tumor microenvironment (cytokines, growth factors, morphogens) and intracellular stimuli (microRNAs, oncogenes, tumor suppressor genes) variably associated with specific disease mechanisms, including chronic inflammation and hypoxia. Nevertheless, evidence supporting a complete EMT of neoplastic cholangiocytes into stromal cells is lacking, and the gain of EMT-like changes by CCA cells rather reflects a shift towards an enhanced pro-invasive phenotype, likely induced by the tumor stroma. This concept may help to identify new biomarkers of early metastatic behavior along with potential therapeutic targets.

Annexin A8 identifies a subpopulation of transiently quiescent c-kit positive luminal progenitor cells of the ductal mammary epithelium

We have previously shown that Annexin A8 (ANXA8) is strongly associated with the basal-like subgroup of breast cancers, including BRCA1-associated breast cancers, and poor prognosis; while in the mouse mammary gland AnxA8 mRNA is expressed in low-proliferative isolated pubertal mouse mammary ductal epithelium and after enforced involution, but not in isolated highly proliferative terminal end buds (TEB) or during pregnancy. To better understand ANXA8's association with this breast cancer subgroup we established ANXA8's cellular distribution in the mammary gland and ANXA8's effect on cell proliferation. We show that ANXA8 expression in the mouse mammary gland was strong during pre-puberty before the expansion of the rudimentary ductal network and was limited to a distinct subpopulation of ductal luminal epithelial cells but was not detected in TEB or in alveoli during pregnancy. Similarly, during late involution its expression was found in the surviving ductal epithelium, but not in the apoptotic alveoli. Double-immunofluorescence (IF) showed that ANXA8 positive (+ve) cells were ER-alpha negative (-ve) and mostly quiescent, as defined by lack of Ki67 expression during puberty and mid-pregnancy, but not terminally differentiated with ∼15% of ANXA8 +ve cells re-entering the cell cycle at the start of pregnancy (day 4.5). RT-PCR on RNA from FACS-sorted cells and double-IF showed that ANXA8+ve cells were a subpopulation of c-kit +ve luminal progenitor cells, which have recently been identified as the cells of origin of basal-like breast cancers. Over expression of ANXA8 in the mammary epithelial cell line Kim-2 led to a G0/G1 arrest and suppressed Ki67 expression, indicating cell cycle exit. Our data therefore identify ANXA8 as a potential mediator of quiescence in the normal mouse mammary ductal epithelium, while its expression in basal-like breast cancers may be linked to ANXA8's association with their specific cells of origin.

A genome-wide RNAi screen identifies FOXO4 as a metastasis-suppressor through counteracting PI3K/AKT signal pathway in prostate cancer

Activation of the PI3K/AKT signal pathway is a known driving force for the progression to castration-recurrent prostate cancer (CR-CaP), which constitutes the major lethal phenotype of CaP. Here, we identify using a genomic shRNA screen the PI3K/AKT-inactivating downstream target, FOXO4, as a potential CaP metastasis suppressor. FOXO4 protein levels inversely correlate with the invasive potential of a panel of human CaP cell lines, with decreased mRNA levels correlating with increased incidence of clinical metastasis. Knockdown (KD) of FOXO4 in human LNCaP cells causes increased invasion in vitro and lymph node (LN) metastasis in vivo without affecting indices of proliferation or apoptosis. Increased Matrigel invasiveness was found by KD of FOXO1 but not FOXO3. Comparison of differentially expressed genes affected by FOXO4-KD in LNCaP cells in culture, in primary tumors and in LN metastases identified a panel of upregulated genes, including PIP, CAMK2N1, PLA2G16 and PGC, which, if knocked down by siRNA, could decrease the increased invasiveness associated with FOXO4 deficiency. Although only some of these genes encode FOXO promoter binding sites, they are all RUNX2-inducible, and RUNX2 binding to the PIP promoter is increased in FOXO4-KD cells. Indeed, the forced expression of FOXO4 reversed the increased invasiveness of LNCaP/shFOXO4 cells; the forced expression of FOXO4 did not alter RUNX2 protein levels, yet it decreased RUNX2 binding to the PIP promoter, resulting in PIP downregulation. Finally, there was a correlation between FOXO4, but not FOXO1 or FOXO3, downregulation and decreased metastasis-free survival in human CaP patients. Our data strongly suggest that increased PI3K/AKT-mediated metastatic invasiveness in CaP is associated with FOXO4 loss, and that mechanisms to induce FOXO4 re-expression might suppress CaP metastatic aggressiveness.

FOXO transcription factors: their clinical significance and regulation

Members of the class O of forkhead box transcription factors (FOXO) have important roles in metabolism, cellular proliferation, stress resistance, and apoptosis. The activity of FOXOs is tightly regulated by posttranslational modification, including phosphorylation, acetylation, and ubiquitylation. Activation of cell survival pathways such as phosphoinositide-3-kinase/AKT/IKK or RAS/mitogen-activated protein kinase phosphorylates FOXOs at different sites which regulate FOXOs nuclear localization or degradation. FOXO transcription factors are upregulated in a number of cell types including hepatocytes, fibroblasts, osteoblasts, keratinocytes, endothelial cells, pericytes, and cardiac myocytes. They are involved in a number of pathologic and physiologic processes that include proliferation, apoptosis, autophagy, metabolism, inflammation, cytokine expression, immunity, differentiation, and resistance to oxidative stress. These processes impact a number of clinical conditions such as carcinogenesis, diabetes, diabetic complications, cardiovascular disease, host response, and wound healing. In this paper, we focus on the potential role of FOXOs in different disease models and the regulation of FOXOs by various stimuli.

Gene Expression Profiling in Mouse Embryonic Stem Cells Reveals Glycogen Synthase Kinase-3-Dependent Targets of Phosphatidylinositol 3-Kinase and Wnt/β-Catenin Signaling Pathways

Glycogen synthase kinase-3 (Gsk-3) activity is an important regulator of numerous signal transduction pathways. Gsk-3 activity is the sum of two largely redundant proteins, Gsk-3α and Gsk-3β, and in general, Gsk-3 is a negative regulator of cellular signaling. Genetic deletion of both Gsk-3α and Gsk-3β in mouse embryonic stem cells (ESCs) has previously been shown to lead to the constitutive activation of the Wnt/β-catenin signaling pathway. However, in addition to Wnt signaling, all Gsk-3-regulated pathways, such as insulin signaling, are also affected simultaneously in Gsk-3α(-) (/) (-); Gsk-3β(-) (/) (-)ESCs. In an effort to better understand how specific signaling pathways contribute to the global pattern of gene expression in Gsk-3α(-) (/) (-); Gsk-3β(-) (/) (-)ESCs, we compared the gene expression profiles in Gsk-3α(-) (/) (-); Gsk-3β(-) (/) (-) ESCs to mouse ESCs in which either Wnt/β-catenin signaling or phosphatidylinositol 3-kinase (PI3K)-dependent insulin signaling are constitutively active. Our results show that Wnt signaling has a greater effect on up-regulated genes in the Gsk-3α(-) (/) (-); Gsk-3β(-) (/) (-)ESCs, whereas PI3K-dependent insulin signaling is more responsible for the down-regulation of genes in the same cells. These data show the importance of Gsk-3 activity on gene expression in mouse ESCs, and that these effects are due to the combined effects of multiple signaling pathways.

WTAP regulates migration and invasion of cholangiocarcinoma cells

BACKGROUND

Wilms' tumor 1-associating protein (WTAP) is a nuclear protein that has been associated with the regulation of proliferation and apoptosis. Although its dynamic expression and physiological functions in vascular cells have been reported, its expression and roles in cholangiocarcinoma cells are poorly characterized.

METHODS

To examine the expression of WTAP in patient tissues, we performed immunohistochemistry. To examine motility of cholangiocarcinoma cells, we employed Boyden chamber, wound healing and Matrigel invasion assays, and a liver xenograft model.

RESULTS

Immunohistochemistry in patient tissues showed WTAP overexpression in cholangiocarcinoma tissues and correlation of WTAP expression with metastasis of cholangiocarcinoma cells. Overexpression or knockdown of WTAP significantly increased or decreased the motility of cholangiocarcinoma cells. Moreover, WTAP overexpression or knockdown significantly increased or decreased tumorigenicity of cholangiocarcinoma cells in an orthotopic xenograft model. Furthermore, microarray study showed that WTAP induce the expressions of MMP7, MMP28, cathepsin H and Muc1.

CONCLUSION

WTAP is overexpressed in cholangiocarcinoma and regulates motility of cholangiocarcinoma cells.

Lipocalin-2 negatively modulates the epithelial-to-mesenchymal transition in hepatocellular carcinoma through the epidermal growth factor (TGF-beta1)/Lcn2/Twist1 pathway

Lipocalin-2 (Lcn2) is preferentially expressed in hepatocellular carcinoma (HCC). However, the functional role of Lcn2 in HCC progression is still poorly understood, particularly with respect to its involvement in invasion and metastasis. The purpose of this study was to investigate whether Lcn2 is associated with the epithelial-mesenchymal transition (EMT) in HCC and to elucidate the underlying signaling pathway(s). Lcn2 was preferentially expressed in well-differentiated HCC versus liver cirrhosis tissues, and its expression was positively correlated with the stage of HCC. The characteristics of EMT were reversed by adenoviral transduction of Lcn2 into SH-J1 cells, including the down-regulation of N-cadherin, vimentin, alpha-smooth muscle actin, and fibronectin, and the concomitant up-regulation of CK8, CK18, and desmoplakin I/II. Knockdown of Lcn2 by short hairpin RNA (shRNA) in HKK-2 cells expressing high levels of Lcn2 was associated with EMT. Epidermal growth factor (EGF) or transforming growth factor beta1 (TGF-β1) treatment resulted in down-regulation of Lcn2, accompanied by an increase in Twist1 expression and EMT in HCC cells. Stable Lcn2 expression in SH-J1 cells reduced Twist1 expression, inhibited cell proliferation and invasion in vitro, and suppressed tumor growth and metastasis in a mouse model. Furthermore, EGF or TGF-β1 treatment barely changed EMT marker expression in SH-J1 cells ectopically expressing Lcn2. Ectopic expression of Twist1 induced EMT marker expression even in cells expressing Lcn2, indicating that Lcn2 functions downstream of growth factors and upstream of Twist1.

CONCLUSION

Together, our findings indicate that Lcn2 can negatively modulate the EMT in HCC cells through an EGF (or TGF-β1)/Lcn2/Twist1 pathway. Thus, Lcn2 may be a candidate metastasis suppressor and a potential therapeutic target in HCC.

Activation of mammalian target of rapamycin complex 1 (mTORC1) and Raf/Pyk2 by growth factor-mediated Eph receptor 2 (EphA2) is required for cholangiocarcinoma growth and metastasis

Eph receptor 2 (EphA2) overexpression is frequently accompanied by the loss of its cognate ligand during tumor progression. However, the molecular mechanism of this ligand-independent promotion of tumor by EphA2 remains unclear in highly malignant and fatal cholangiocarcinoma (CC). We examined the biological role of EphA2 in tumor growth and metastasis in CC tissues and cells according to the degree of differentiation and we explored the downstream signaling pathways of EphA2. Growth factor-mediated EphA2 overexpression itself leads to the activation of the mammalian target of rapamycin complex 1 (mTORC1) and extracellular signal-regulated kinase (ERK) pathways through ligand-independent activation of EphA2 (phosphorylation of S897). An in vitro soft agar assay and in vivo orthotopic or subcutaneous tumor model showed that EphA2 enhanced colony formation and accelerated tumor growth, and which seemed to be mainly associated with Akt (T308)/mTORC1 activation. Aberrant expression and activation of EphA2 was also associated with poorer differentiation and higher metastatic ability. Enhanced metastatic ability was also observed in an orthotopic tumor model or lung metastasis model, correlating with Pyk2(Y402)/c-Src/ERK activation in addition to activation of the canonical Raf/MEK/ERK pathway. The mTORC1 and Raf/Pyk2 pathways also appeared to affect each other. These results suggest that growth factor-mediated EphA2 might be involved in tumor growth and metastasis through activation of the mTORC1 and Raf/Pyk2 pathways. Therapeutic strategies that target EphA2 and its downstream effectors may be useful to control CC. (HEPATOLOGY 2013;57:2248-2260).

miR-421 induces cell proliferation and apoptosis resistance in human nasopharyngeal carcinoma via downregulation of FOXO4

microRNAs have been demonstrated to play important roles in cancer development and progression. Hence, identifying functional microRNAs and better understanding of the underlying molecular mechanisms would provide new clues for the development of targeted cancer therapies. Herein, we reported that a microRNA, miR-421 played an oncogenic role in nasopharyngeal carcinoma. Upregulation of miR-421 induced, whereas inhibition of miR-421 repressed cell proliferation and apoptosis resistance. Furthermore, we found that upregulation of miR-421 inhibited forkhead box protein O4 (FOXO4) signaling pathway following downregulation of p21, p27, Bim and FASL expression by directly targeting FOXO4 3'UTR. Additionally, we demonstrated that FOXO4 expression is critical for miR-421-induced cell growth and apoptosis resistance. Taken together, our findings not only suggest that miR-421 promotes nasopharyngeal carcinoma cell proliferation and anti-apoptosis, but also uncover a novel regulatory mechanism for inactivation of FOXO4 in nasopharyngeal carcinoma.

The challenge of cholangiocarcinoma: dissecting the molecular mechanisms of an insidious cancer

Cholangiocarcinoma is a fatal cancer of the biliary epithelium and has an incidence that is increasing worldwide. Survival beyond a year of diagnosis is less than 5%, and therapeutic options are few. Known risk factors include biliary diseases such as primary sclerosing cholangitis and parasitic infestation of the biliary tree, but most cases are not associated with any of these underlying diseases. Numerous in vitro and in vivo models, as well as novel analytical techniques for human samples, are helping to delineate the many pathways implicated in this disease, albeit at a frustratingly slow pace. As yet, however, none of these studies has been translated into improved patient outcome and, overall, the pathophysiology of cholangiocarcinoma is still poorly understood. There remains an urgent need for new approaches and models to improve management of this insidious and devastating disease. In this review, we take a bedside-to-bench approach to discussing cholangiocarcinoma and outline research opportunities for the future in this field.

Involvement of annexin A8 in the properties of pancreatic cancer

Although Annexin A8 (ANXA8), a member of a superfamily of calcium and phospholipid binding proteins, is physiologically expressed in a tissue-specific manner, recent microarray studies reported that ANXA8 was also ectopically expressed in pancreatic cancers. We investigated the molecular mechanism of expression of ANXA8 in cancer cells and its functional role in pancreatic cancer cells. ANXA8 was diversely expressed in human cancer cell lines. Expression was enhanced by treatment with 5-aza-dC and butyrate, and correlated with methylation status at CpG in the promoter-exon 1 region. Inhibition of ANXA8 using siRNA in BxPC-3 cells which express ANXA8 at a high level elevated caspase-3 and -7 activities. In in vitro invasion assay, inhibition of ANXA8 using siRNA in BxPC-3 reduced the numbers of migrating cells, and down-regulated HIF-1α mRNA transcription. Overexpression of ANXA8 increased the number of viable cells and BrdU incorporation in PANC-1 cells, which express ANXA8 at a low level. Expression of ANXA8 was induced under conditions of nutrient deprivation, and overexpression of ANXA8 showed resistance against serum starvation in PANC-1 cells. In a promoter assay, co-transfection with the expression vector of ANXA8 and the vector of a reporter gene containing the promoter of HIF-1α enhanced HIF-1α promoter activity. In contrast, this effect of ANXA8 was inhibited by administration of BAPTA-AM, an intracellular Ca²⁺ chelator. These results suggest that ectopic ANXA8 expression in cancer cells might involve an epigenetic mechanism. ANXA8 might play an important role in calcium fluctuation-mediated HIF-1α transcriptional activation and cell viability.

Tumor necrosis factor-α (TNF-α) stimulates the epithelial-mesenchymal transition regulator Snail in cholangiocarcinoma

Epithelial-mesenchymal transition (EMT) is a series of events during which epithelial cells lose many of their epithelial characteristics and take on properties that are typical of mesenchymal cells that lack cell-cell adhesion properties. EMT may be activated by various types of growth factors or inflammatory cytokines. In many types of epithelial cancers, the EMT-derived tumor cells are susceptible to metastasis. During tumor progression, epithelial cells acquire a gene expression pattern closely resembling that of mesenchymal cells. This study aimed to investigate the expression of the EMT-associated transcription factor Snail and an adhesion molecule E-cadherin in cholangiocarcinoma (CCA) tissues. The effect of TNF-α on EMT activation in CCA cells was also demonstrated. The qRT-PCR analysis revealed that Snail expression significantly increased in CCA (P = 0.01) and was correlated with tumor metastasis (P = 0.02). The expression of Snail was inversely associated with E-cadherin (P = 0.004). The stimulation of TNF-α enhances migration behavior and showed significantly induced expression of Snail in CCA cell lines, whereas expression of E-cadherin and CK-19 (the epithelial marker) was reduced. Immunofluorescence analysis revealed that TNF-α-treated CCA cell lines increased nuclear translocation of Snail, whereas E-cadherin was dramatically decreased. Our findings suggest that the changes in the expression of Snail or E-cadherin might regulate EMT development in CCA resulting in promoting tumor progression. Overexpression of Snail could be used as a prognostic marker for monitoring the treatment efficiency of CCA patients.

Cell surface annexins regulate ADAM-mediated ectodomain shedding of proamphiregulin

Ectodomain shedding of EGFR ligands by ADAM17 is a key step of transactivation of epidermal growth factor receptor (EGFR) and the downstream signaling network. In this study, we identified cell surface annexins as regulators of ectodomain shedding of amphiregulin precursor. We propose that cell surface annexins act as a shedding platform to determine the substrate selectivity of ADAM17.

A disintegrin and metalloproteinase (ADAM) is a family of enzymes involved in ectodomain shedding of various membrane proteins. However, the molecular mechanism underlying substrate recognition by ADAMs remains unknown. In this study, we successfully captured and analyzed cell surface transient assemblies between the transmembrane amphiregulin precursor (proAREG) and ADAM17 during an early shedding phase, which enabled the identification of cell surface annexins as components of their shedding complex. Annexin family members annexin A2 (ANXA2), A8, and A9 interacted with proAREG and ADAM17 on the cell surface. Shedding of proAREG was increased when ANXA2 was knocked down but decreased with ANXA8 and A9 knockdown, because of enhanced and impaired association with ADAM17, respectively. Knockdown of ANXA2 and A8 in primary keratinocytes altered wound-induced cell migration and ultraviolet B–induced phosphorylation of epidermal growth factor receptor (EGFR), suggesting that annexins play an essential role in the ADAM-mediated ectodomain shedding of EGFR ligands. On the basis of these data, we propose that annexins on the cell surface function as “shedding platform” proteins to determine the substrate selectivity of ADAM17, with possible therapeutic potential in ADAM-related diseases.

MicroRNA-499-5p promotes cellular invasion and tumor metastasis in colorectal cancer by targeting FOXO4 and PDCD4

MicroRNAs (miRNAs) regulate tumor progression and invasion via direct interaction with target messenger RNAs (mRNAs). We defined miRNAs involved in cancer metastasis (metastamirs) using an established in vitro colorectal cancer (CRC) model of minimally metastatic cells (SW480 line) from a colon adenocarcinoma primary lesion and highly metastatic cells (SW620 line) from a metastatic lymph node from the same patient 1 year later. We used microarray analysis to identify miRNAs differentially expressed in SW480 and SW620 cells, focusing on miR-499-5p as a novel candidate prometastatic miRNA whose functions in cancer had not been studied. We confirmed increased miR-499-5p levels in highly invasive CRC cell lines and lymph node-positive CRC specimens. Furthermore, enhancing the expression of miR-499-5p promoted CRC cell migration and invasion in vitro and lung and liver metastasis in vivo, while silencing its expression resulted in reduced migration and invasion. Additionally, we identified FOXO4 and PDCD4 as direct and functional targets of miR-499-5p. Collectively, these findings suggested that miR-499-5p promoted metastasis of CRC cells and may be useful as a new potential therapeutic target for CRC.