Overexpression of eukaryotic initiation factor 5A2 enhances cell motility and promotes tumor metastasis in hepatocellular carcinoma

Biomarkers for predicting future metastasis of human gastrointestinal tumors

The recent advances in surgery and radiation therapy have significantly improved the prognosis of patients with primary cancer, and the major challenge of cancer treatment now is metastatic disease development. The 5-year survival rate of cancer patients who have distant metastasis at diagnosis is extremely low, suggesting that prediction and early detection of metastasis would definitely improve their prognosis because suitable patient therapeutic management and treatment strategy can be provided. Cancer cells from a primary site give rise to a metastatic tumor via a number of steps which require the involvement and altered expression of many regulators. These regulators may serve as biomarkers for predicting metastasis. Over the past few years, numerous regulators have been found correlating with metastasis. In this review, we summarize the findings of a number of potential biomarkers that are involved in cadherin-catenin interaction, integrin signaling, PI3K/Akt/mTOR signaling and cancer stem cell identification in gastrointestinal cancers. We will also discuss how certain biomarkers are associated with the tumor microenvironment that favors cancer metastasis.

Down-regulation of eIF5A-2 prevents epithelial-mesenchymal transition in non-small-cell lung cancer cells

BACKGROUND

Epithelial-mesenchymal transition (EMT) is believed to be the critical process in malignant tumor invasion and metastases, and has a great influence on improving the survival rate in non-small-cell lung cancer (NSCLC) patients. Recent studies suggested that eukaryotic initiation factor 5A-2 (eIF5A-2) might serve as an adverse prognostic marker of survival. We detected eIF5A-2 in NSCLC A549 cells, and found that the invasive capability correlates with the eIF5A-2 expression.

METHODS

Transforming growth factor (TGF)-β1 was used to induce EMT in A549 cells. Western blotting, immunofluorescence, wound healing assay, and transwell-matrigel invasion chambers were used to identify phenotype changes. Western blotting was also used to observe changes of the expression of eIF5A-2. We down-regulated the eIF5A-2 expression using an eIF5A-2 siRNA and identified the phenotype changes by western blotting and immunofluorescence. We tested the change of migration and invasion capabilities of A549 cells by the wound healing assay and transwell-matrigel invasion chambers.

RESULTS

After stimulating with TGF-β1, almost all A549 cells changed to the mesenchymal phenotype and acquired more migration and invasion capabilities. These cells also had higher eIF5A-2 protein expression. Down-regulation of eIF5A-2 expression with eIF5A-2 siRNA transfection could change the cells from mesenchymal to epithelial phenotype and decrease tumor cell migration and invasive capabilities significantly.

CONCLUSIONS

The expression of eIF5A-2 was up-regulated following EMT phenotype changes in A549 cells, which correlated with enhanced tumor invasion and metastatic capabilities. Furthermore, in the A549 cell line, the process of EMT phenotype change could be reversed by eIF5A-2 siRNA, with a consequent weakening of both invasive and metastatic capabilities.

MicroRNA-21 regulates the migration and invasion of a stem-like population in hepatocellular carcinoma

Due to invasion and intrahepatic metastasis, the prognosis for patients with hepatocellular carcinoma (HCC) is poor. However, the mechanisms underlying these processes of HCC remain unclear. Cancer stem cells may be involved in early systemic dissemination and metastasis formation and side population (SP) cells isolated from diverse cancer cells possess stem cell-like properties. However, the mechanisms involved in migration and invasion of cancer stem cells are not well understood. In this study, we identified and isolated populations of SP cells from HCC cell lines using flow cyto-metry. SP cells showed higher levels of migration and invasion capability. Higher expression of miR-21 was observed in SP cells. Silencing of miR-21 led to a reduction in the migration and invasion of these cells and overexpression of miR-21 can increase in cell migration and invasion. Overexpression of miR-21 did not cause degradation of PTEN or RECK or PDCD4 mRNA but drastically inhibited its protein expression. Consistent with these results, silencing miR-21 increased the levels of PTEN, RECK and PDCD4 protein, respectively. The role of silencing miR-21 was partially attenuated by silencing of PTEN or RECK or PDCD4 mRNA. The results of this study revealed the aberrant expression of miR-21 in SP cells and showed that miR-21 regulates the expression of multiple target proteins that are associated with tumor dissemination. MiR-21 is a pro-metastatic miRNA in SP cells and raises the possibility that therapy of HCC may be improved by pharmaceutical strategies directed towards miR-21.

A microarray-based gene expression analysis to identify diagnostic biomarkers for unknown primary cancer

Background

The biological basis for cancer of unknown primary (CUP) at the molecular level remains largely unknown, with no evidence of whether a common biological entity exists. Here, we assessed the possibility of identifying a common diagnostic biomarker for CUP using a microarray gene expression analysis.

Methods

Tumor mRNA samples from 60 patients with CUP were analyzed using the Affymetrix U133A Plus 2.0 GeneChip and were normalized by asinh (hyperbolic arc sine) transformation to construct a mean gene-expression profile specific to CUP. A gene-expression profile specific to non-CUP group was constructed using publicly available raw microarray datasets. The t-tests were performed to compare the CUP with non-CUP groups and the top 59 CUP specific genes with the highest fold change were selected (p-value<0.001).

Results

Among the 44 genes that were up-regulated in the CUP group, 6 genes for ribosomal proteins were identified. Two of these genes (RPS7 and RPL11) are known to be involved in the Mdm2–p53 pathway. We also identified several genes related to metastasis and apoptosis, suggesting a biological attribute of CUP.

Conclusions

The protein products of the up-regulated and down-regulated genes identified in this study may be clinically useful as unique biomarkers for CUP.

Role of p38 and JNK MAPK signaling pathways and tumor suppressor p53 on induction of apoptosis in response to Ad-eIF5A1 in A549 lung cancer cells

BACKGROUND

The eukaryotic translation initiation factor 5A1 (eIF5A1) is a highly conserved protein involved in many cellular processes including cell division, translation, apoptosis, and inflammation. Induction of apoptosis is the only function of eIF5A1 that is known to be independent of post-translational hypusine modification. In the present study, we investigated the involvement of mitogen- and stress-activated protein kinases during apoptosis of A549 lung cancer cells infected with adenovirus expressing eIF5A1 or a mutant of eIF5A1 that cannot be hypusinated (eIF5A1K50A).

METHODS

Using adenoviral-mediated transfection of human A549 lung cancer cells to over-express eIF5A1 and eIF5A1K50A, the mechanism by which unhypusinated eIF5A1 induces apoptosis was investigated by Western blotting, flow cytometry, and use of MAPK and p53 inhibitors.

RESULTS

Phosphorylation of ERK, p38 MAPK, and JNK was observed in response to adenovirus-mediated over-expression of eIF5A1 or eIF5A1K50A, along with phosphorylation and stabilization of the p53 tumor suppressor protein. Synthetic inhibitors of p38 and JNK kinase activity, but not inhibitors of ERK1/2 or p53 activity, significantly inhibited apoptosis induced by Ad-eIF5A1. Importantly, normal lung cells were more resistant to apoptosis induced by eIF5A1 and eIF5A1K50A than A549 lung cancer cells.

CONCLUSIONS

Collectively these data indicate that p38 and JNK MAP kinase signaling are important for eIF5A1-induced cell death and that induction of apoptosis was not dependent on p53 activity.

Knockdown of ZFX inhibits gastric cancer cell growth in vitro and in vivo via downregulating the ERK-MAPK pathway

Zinc finger protein X-linked (ZFX) is a zinc finger transcription factor encoded on the X chromosome. Here, we found that ZFX expression was significantly upregulated in gastric cancer (GC) cell lines and tissues. Knockdown of ZFX induced significant apoptosis and cell cycle arrest in SGC7901 and MGC803 cells. Moreover, we demonstrated for the first time that knockdown of ZFX inhibited gastric cancer cell growth in vitro and in vivo via downregulating the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) pathway. Therefore, ZFX play a prominent role in GC tumorigenicity and may have potential applications in the diagnosis or treatment of GC.

Morpho-mechanical intestinal remodeling in type 2 diabetic GK rats--is it related to advanced glycation end product formation?

Little is known about the mechanisms for the biomechanical remodeling in diabetes. The histomorphology, passive biomechanical properties and expression of advanced glycation end product (N epsilon-(carboxymethyl) lysine, AGE) and its receptor (RAGE) were studied in jejunal segments from 8 GK diabetic rats (GK group) and 10 age-matched normal rats (Normal group). The mechanical test was done by using a ramp distension of fluid into the jejunal segments in vitro. Circumferential stress and strain were computed from the length, diameter and pressure data and from the zero-stress state geometry. AGE and RAGE were detected by immunohistochemistry staining. Linear regression analysis was done to study association between the glucose level and AGE/RAGE expression with the histomorphometric and biomechanical parameters. The blood glucose level, the jejunal weight per length, wall thickness, wall area and layer thickness significantly increased in the GK group compared with the Normal group (P<0.05, P<0.01 and P<0.001). The opening angle and absolute values of residual strain decreased whereas the circumferential stiffness of the jejunal wall increased in the GK group (P<0.05 and P<0.01). Furthermore, stronger AGE expression in the villi and crypt and RAGE expression in the villi were found in the GK group (P<0.05 and P<0.01). Most histomorphometric and biomechanical changes were associated with blood glucose level and AGE/RAGE expression. In conclusion, histomorphometric and biomechanical remodeling occurred in type 2 diabetic GK rats. The increasing blood glucose level and the increased AGE/RAGE expression were associated with the remodeling, indicating a causal relationship.

Translational control in cancer etiology

The link between perturbations in translational control and cancer etiology is becoming a primary focus in cancer research. It has now been established that genetic alterations in several components of the translational apparatus underlie spontaneous cancers as well as an entire class of inherited syndromes known as "ribosomopathies" associated with increased cancer susceptibility. These discoveries have illuminated the importance of deregulations in translational control to very specific cellular processes that contribute to cancer etiology. In addition, a growing body of evidence supports the view that deregulation of translational control is a common mechanism by which diverse oncogenic pathways promote cellular transformation and tumor development. Indeed, activation of these key oncogenic pathways induces rapid and dramatic translational reprogramming both by increasing overall protein synthesis and by modulating specific mRNA networks. These translational changes promote cellular transformation, impacting almost every phase of tumor development. This paradigm represents a new frontier in the multihit model of cancer formation and offers significant promise for innovative cancer therapies. Current research, in conjunction with cutting edge technologies, will further enable us to explore novel mechanisms of translational control, functionally identify translationally controlled mRNA groups, and unravel their impact on cellular transformation and tumorigenesis.

eIF5A isoforms and cancer: two brothers for two functions?

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the unusual amino acid hypusine [N(ε)-(4-amino-2-hydroxybutyl)lysine]. The role of hypusine formation in the eIF5A protein in the regulation of cell proliferation and apoptosis is addressed in the present review. Moreover, vertebrates carry two genes that encode two eIF5A isoforms, eIF5A-1 and eIF5A-2, which, in humans, are 84% identical. However, the biological functions of these two isoforms may be significantly different. In fact, eIF5A-1 is demonstrable in most cells of different histogenesis, whereas eIF5A-2 protein is detectable only in certain human cancer cells or tissues, suggesting its role as a potential oncogene. In this review we focus our attention on the involvement of eIF5A-1 in the triggering of an apoptotic program and in the regulation of cell proliferation. In addition, the potential oncogenic role and prognostic significance of eIF5A-2 in the prediction of the survival of cancer patients is described. eIF5A-1 and/or the eIF5A-2 isoform may serve as a new molecular diagnostic or prognostic marker or as a molecular target for anti-cancer therapy.

Mitochondrial proteomics of nasopharyngeal carcinoma metastasis

Background

Mitochondrial proteomic alterations of nasopharyngeal carcinoma metastasis remain unknown. Our purpose is to screen mitochondrial proteins for the elucidation of the molecular mechanisms of nasopharyngeal carcinoma metastasis and the discovery of metastasis-related biomarkers.

Methods

Mitochondria were isolated from nasopharyngeal carcinoma metastatic (5-8F) and nonmetastatic (6-10B) cell lines, respectively. After characterization of isolated mitochondria, mitochondrial differentially expressed proteins (DEPs) were quantified by two-dimensional difference in-gel electrophoresis (2D-DIGE), and identified by peptide mass fingerprint (PMF) and tandem mass spectrometry (MS/MS). A functional enrichment analysis and a protein-protein interaction sub-network analysis for DEPs were carried out with bioinformatics. Furthermore, siRNAs transient transfections were used to suppress expressions of some up-regulated DEPs in metastatic cells (5-8F), followed by Transwell Migration assay.

Results

Sixteen mitochondrial DEPs including PRDX3 and SOD2 were identified. Those 5-8F cells with suppression of PRDX3 showed an increased mobility potential. The functional enrichment analyses of DEPs discovered five significant biological processes including cellular response to reactive oxygen species, hydrogen peroxide metabolic process, regulation of mitochondrial membrane potential, cell redox homeostasis and oxidation reduction, and five significant molecular functions including oxidoreductase activity, caspase inhibitor activity, peroxiredoxin activity, porin activity and antioxidant activity. A protein-protein interaction sub-network of DEPs was generated with literature data. Ten mitochondrial DEPs including PRDX3, PRDX6, SOD2, ECH1, SERPINB5, COX5A, PDIA5, EIF5A, IDH3B, and PSMC4 were rationalized in the tumor-stroma co-evolution model that mitochondrial oxidative stress directly contributes to tumor metastasis.

Conclusions

Sixteen mitochondrial DEPs were identified with mass spectrometry and ten of them were rationalized in the tumor-stroma co-evolution model. Those 5-8F cells with suppression of PRDX3 showed an increased mobility potential. These data suggest that those mitochondrial DEPs are potential biomarkers for NPC metastasis, and their dysregulation would play important roles in mitochondria oxidative stress-mediated NPC metastatic process.

Proteomic and phosphoproteomic analysis of chicken embryo fibroblasts infected with cell culture-attenuated and vaccine strains of Marek's disease virus

Vaccination is an effective strategy to reduce the loss of chickens in the poultry industry caused by Marek's Disease (MD), an avian lymphoproliferative disease. The vaccines currently used are from attenuated serotype 1 Marek's disease virus (MDV) or naturally nononcogenic MDV strains. To prepare for future immunity breaks, functional genomic and proteomic studies have been used to better understand the underlying mechanisms of MDV pathogenicity and the effects induced by the vaccine viruses. In this study, a combined approach of quantitative GeLC-MSE and qualitative ERLIC/IMAC/LC-MS/MS analysis were used to identify abundance changes of proteins and the variations of phosphorylation status resulting from the perturbations due to infection with an attenuated oncogenic virus strain (Md11/75C) and several nononcogenic virus strains (CVI988, FC126 and 301B) in vitro. Using this combined approach, several signal transduction pathways mapped by the identified proteins were found to be altered at both the level of protein abundance and phosphorylation. On the basis of this study, a kinase-dependent pathway to regulate phosphorylation of 4E-BP1 to modulate assembly of the protein translation initiation complex was revealed. The differences of 4E-BP1 phosphorylation patterns as well as the measured abundance changes among several other proteins that regulate host transcriptional and translational activities across the virus strains used in this study provide new insight for future functional and biochemical characterization of specific proteins involved in MDV pathogenesis.

The role of acetylation in the subcellular localization of an oncogenic isoform of translation factor eIF5A

Mammalian cells express two isoforms of eIF5A, eIF5A1 and eIF5A2, but little is known about the function of eIF5A2. Here we report that eIF5A2 is reversibly acetylated at lysine-47. HDAC6 and SIRT2 were identified as the enzymes responsible for deacetylating eIF5A2. Analysis using acetylation-deficient mutants indicated that acetylation regulates the subcellular localization of eIF5A2.

Protein-protein-interaction network organization of the hypusine modification system

Hypusine modification of eukaryotic initiation factor 5A (eIF-5A) represents a unique and highly specific post-translational modification with regulatory functions in cancer, diabetes, and infectious diseases. However, the specific cellular pathways that are influenced by the hypusine modification remain largely unknown. To globally characterize eIF-5A and hypusine-dependent pathways, we used an approach that combines large-scale bioreactor cell culture with tandem affinity purification and mass spectrometry: "bioreactor-TAP-MS/MS." By applying this approach systematically to all four components of the hypusine modification system (eIF-5A1, eIF-5A2, DHS, and DOHH), we identified 248 interacting proteins as components of the cellular hypusine network, with diverse functions including regulation of translation, mRNA processing, DNA replication, and cell cycle regulation. Network analysis of this data set enabled us to provide a comprehensive overview of the protein-protein interaction landscape of the hypusine modification system. In addition, we validated the interaction of eIF-5A with some of the newly identified associated proteins in more detail. Our analysis has revealed numerous novel interactions, and thus provides a valuable resource for understanding how this crucial homeostatic signaling pathway affects different cellular functions.

GEF-H1 over-expression in hepatocellular carcinoma promotes cell motility via activation of RhoA signalling

The interstitial chromosome (chr.) 1q21-q22 region is frequently amplified in human cancers, where it has been reported to carry prognostic significance for patients. We attempted to delineate chr. 1q21-q22 for affected gene(s) in hepatocellular carcinoma (HCC) by array-CGH and detected copy number gains of ρ-guanine nucleotide exchange factor-H1 (GEF-H1) as most significant event. Gene expression evaluation in the HCC cohort indicated common up-regulations of GEF-H1 in 64% tumours compared to adjacent non-tumoural liver (64/100; paired t-test p < 0.0001). Moreover, GEF-H1 over-expressions correlated with microvascular invasion and advanced-stage tumours (p < 0.05). High GEF-H1 levels also predict shorter disease-free and overall survival of HCC patients (p < 0.03). Functional knock-down of GEF-H1 by RNAi indicated marked reduction in cell invasion through matrigel and an inhibition of cell migration (p < 0.035), but an effect on cell viability was not apparent. More interestingly, a mesenchymal-epithelial transition (MET) was readily observed in GEF-H1 knock-down cells, where a concomitant re-expression of epithelial markers (E-cadherin and cytokeratin 18) and cell adhesion proteins (α-catenin and γ-catenin) was found but down-regulation of mesenchymal features (N-cadherin, vimentin and fibronectin). This phenotype was accompanied by reduced filamentous actin polymerizations and diminution of the stress fibre formation. In addition, reduced active form of GTP-RhoA, together with its downstream effectors, including cleaved ROCK1 and phosphorylated MLC2, were also detected in GEF-H1-depleted cells. Taken together, our findings underscore a potent oncogenic role for GEF-H1 in promoting the metastatic potentials of HCC, possibly through activation of RhoA signalling and the EMT phenomenon.

Interleukin 23 promotes hepatocellular carcinoma metastasis via NF-kappa B induced matrix metalloproteinase 9 expression

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most popular cancers in the world with poor prognosis, which often develops from chronic liver inflammatory diseases. Interleukin 23 (IL-23) is an inflammatory cytokine which is reported to play an important role in tumor development in animal model. While the function of IL-23 in HCC development remains unknown, so we investigate the role of IL-23 in HCC progression in this study.

METHODOLOGY AND PRINCIPAL FINDING

Transcript level of IL-23, interleukin17A (IL-17A) and matrix metalloproteinases 9 (MMP9) in clinical HCC samples (n=81) was determined by qPCR. Protein expression pattern of IL-23 in primary and metastatic HCC tissues pairs (n=49 pairs) was determined by immunohistochemistry staining. Cell migration, invasion, RNA interfering and immune blotting were used to characterize the functional and signaling mechanisms in IL-23-treated HCC. Compared with paired non-tumor tissue, higher IL-23 expression was detected in HCC tumor tissues with metastasis. Immunohistochemistry staining confirmed the high expression of IL-23 in metastasis HCC. Immune blotting demonstrated that IL-23 was highly expressed in HCC cell lines with metastasis. Functional study found that IL-23 could promote HCC cell migration and invasion. Molecular analysis revealed that IL-23 could upregulate MMP9 expression via NF-κB/p65 signaling activation and IL-17A could improve IL-23 expression in tumor cells directly via activating NF-κB/p65 signaling pathway.

CONCLUSIONS

IL-23 could promote HCC metastasis by the upregulation of MMP9 expression via activating NF-κB/p65 signaling pathway. At the same time, IL-17A could further promote IL-23 expression in HCC tumor cells.

Downregulation of the Notch signaling pathway inhibits hepatocellular carcinoma cell invasion by inactivation of matrix metalloproteinase-2 and -9 and vascular endothelial growth factor

Hepatocellular carcinoma (HCC) is one of the most common malignancies. The main cause of death in HCC patients is tumor progression with invasion and metastasis. However, the underlying mechanisms of HCC invasion and metastasis are still not fully understood. Some studies show that the Notch signaling pathway may participate in tumor invasion and metastasis. However, the mechanisms by which the Notch signaling pathway mediates tumor cell invasion, especially in hepatocellular carcinoma, are not yet known. In the current study, we investigated the anti-invasion effect of the downregulation of the Notch signaling pathway by DAPT in HCC cells. The Notch signaling pathway inhibitor could suppress invasion of HCC cells via the extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling pathways, resulting in the downregulation of matrix metalloproteinase-2 and -9 (MMP-2 and -9) and vascular endothelial growth factor (VEGF). These observations suggested that inhibition of the Notch signaling pathway by DAPT would be useful for devising novel preventive and therapeutic strategies targeting invasion of HCC.

Bidirectional regulation between WDR83 and its natural antisense transcript DHPS in gastric cancer

Natural antisense transcripts (NATs) exist ubiquitously in mammalian genomes and play roles in the regulation of gene expression. However, both the existence of bidirectional antisense RNA regulation and the possibility of protein-coding genes that function as antisense RNAs remain speculative. Here, we found that the protein-coding gene, deoxyhypusine synthase (DHPS), as the NAT of WDR83, concordantly regulated the expression of WDR83 mRNA and protein. Conversely, WDR83 also regulated DHPS by antisense pairing in a concordant manner. WDR83 and DHPS were capable of forming an RNA duplex at overlapping 3' untranslated regions and this duplex increased their mutual stability, which was required for the bidirectional regulation. As a pair of protein-coding cis-sense/antisense transcripts, WDR83 and DHPS were upregulated simultaneously and correlated positively in gastric cancer (GC), driving GC pathophysiology by promoting cell proliferation. Furthermore, the positive relationship between WDR83 and DHPS was also observed in other cancers. The bidirectional regulatory relationship between WDR83 and DHPS not only enriches our understanding of antisense regulation, but also provides a more complete understanding of their functions in tumor development.

Implications of the Use of Eukaryotic Translation Initiation Factor 5A (eIF5A) for Prognosis and Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver malignancy and accounts for most of the total liver cancer cases. Lack of treatment options and late diagnosis contribute to high mortality rate of HCC. In eukaryotes, translation of messenger RNA (mRNA) to protein is a key process in protein biosynthesis in which initiation of translation involves interaction of different eukaryotic translation initiation factors (eIFs), ribosome subunits and mRNAs. Eukaryotic translation initiation factor 5A (eIF5A) is one of the eIFs involved in translation initiation and eIF5A2, one of its isoforms, is upregulated in various cancers including HCC as a result of chromosomal instability, where it resides. In HCC, eIF5A2 expression is associated with adverse prognosis such as presence of tumor metastasis and venous infiltration. Based on eIF5A2 functional studies, suppressing eIF5A2 expression by short interfering RNA alleviates the tumorigenic properties of HCC cells in vitro while ectopic expression of eIF5A2 enhances the aggressiveness of HCC cells in vivo and in vitro by inducing epithelial-mesenchymal transition. In conclusion, eIF5A2 is a potential prognostic marker as well as a therapeutic target for HCC.

Identification of transaldolase as a novel serum biomarker for hepatocellular carcinoma metastasis using xenografted mouse model and clinic samples

Hepatocellular carcinoma (HCC) is one of serious disorders with the highest morbidities and mortalities worldwide. Metastasis is the major concern that causes death in HCC. The goal of this study was to screen and identify potential serum proteins indicating HCC metastasis. Serum samples collected from control and HCCLM3-R metastatic HCC tumor model at specific stages of metastasis (1 wk, 3 wks and 6 wks) were subjected to iTRAQ labeling followed by 2DLC-ESI-MS/MS analysis. A total of 554 proteins were identified and 80 proteins were differential expressed at least between one adjacent time points. Among them, expression level of transaldolase (TALDO) was validated in mouse and human serum. The level of TALDO protein was found to be higher in metastatic mice serum compared to that of non-metastatic mice. Human specific TALDO was then identified in mouse serum through human specific peptides. Immunohistochemical and western blot analysis showed that the expression of TALDO in human HCC tissues and HCC cell lines was associated with its metastatic behavior. Subsequent screening of TALDO expression in 72 clinical serum samples (comprising 36 non-metastatic HCC and 36 metastatic HCC samples) revealed higher TALDO level in the serum of metastatic HCC patients. A receiver operating characteristic (ROC) curve estimated a maximal sensitivity of 77.8% and 86.1% specificity for TALDO in detection of HCC metastasis. The present results demonstrated that the nude mouse xenograft model is an efficient system for performing metastasis-related biomarker discovery. TALDO may be useful biomarkers for the detection of HCC metastasis.

The effect of miR-7 on behavior and global protein expression in glioma cell lines

Malignant glioma is a common cancer of the nervous system. Despite recent research efforts in cancer therapy, the prognosis of patients with malignant glioma has remained dismal. MicroRNAs are noncoding RNAs that inhibit the expression of their targets in a sequence-specific manner, and a few have been shown to act as oncogenes or tumor suppressors. Here, we aimed at exploring the precise biological role of microRNA-7 (miR-7) and the global protein changes in glioma cell lines transiently transfected with miR-7. Transfection of miR-7 into glioma cell lines causes inhibition of cell migration and invasion and suppression of tumorigenesis. Moreover, ectopic expression of miR-7 inhibits lung metastases of glioma in vivo. Among 65 protein spots with differential expression separated by 2-DE, 37 proteins were successfully identified by MS/MS analysis. Of those, the 25 downregulated proteins, which include 14-3-3ζ, eukaryotic translation initiation factor 5A (EIF5A), and annexin A4, may be downstream targets of miR-7, a finding that could elucidate some aspects of the behavior of glioma cells at the protein level. In conclusion, the absence of miR-7 function could cause downstream molecules to switch on or off, resulting in glioma development, invasion, and metastases. MiR-7-based gene treatment may be a novel anti-invasion therapeutic strategy for malignant glioma.

Skin delivery of short hairpin RNA of indoleamine 2,3 dioxygenase induces antitumor immunity against orthotopic and metastatic liver cancer

Liver cancer is one of the most malignant cancers in the world and has a high rate of metastasis. Therefore, development of a novel therapy for liver cancer is a critical issue. Indoleamine 2,3-dioxygenase (IDO) is known as a negative immune regulator in dendritic cells. Our previous study demonstrated that skin delivery of IDO short hairpin RNA (shRNA) induced antitumor immunity in subcutaneous bladder and colon tumor models. Because the immunological environment is quite different between skin and liver, it is essential to evaluate whether skin delivery of IDO shRNA is an effective treatment in metastatic and orthotopic animal tumor models. In the present study, IDO shRNA inhibited tumor growth in subcutaneous, metastatic and orthotopic liver tumor models. The cytotoxicity of splenocytes was significantly elevated in mice treated with IDO shRNA in the orthotopic and metastatic tumor models. Interleukin (IL)-12 and interferon (IFN)-gamma mRNA expression were upregulated while IL-10 was downregulated in the inguinal lymph nodes, which were collected from IDO shRNA-treated mice. Similar results were observed in the spleens of mice inoculated with IDO shRNA by gene gun. The results indicate that skin administration of IDO shRNA is an effective therapy in orthotopic and metastatic liver cancer animal models. Indoleamine 2,3-dioxygenase shRNA might be a potential new treatment for liver cancer in the future.

Genetic variations in plasma circulating DNA of HBV-related hepatocellular carcinoma patients predict recurrence after liver transplantation

BACKGROUND

Recurrence prediction of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients undergoing liver transplantation (LT) present a great challenge because of a lack of biomarkers. Genetic variations play an important role in tumor development and metastasis.

METHODS

Oligonucleotide microarrays were used to evaluate the genetic characteristics of tumor DNA in 30 HBV-related HCC patients who were underwent LT. Recurrence-related single-nucleotide polymorphism were selected, and their prognostic value was assessed and validated in two independent cohorts of HCC patients (N = 102 and N = 77), using pretransplant plasma circulating DNA. Prognostic significance was assessed by Kaplan-Meier survival estimates and log-rank tests. Multivariate analyses were performed to evaluate prognosis-related factors.

RESULTS

rs894151 and rs12438080 were significantly associated with recurrence (P = .003 and P = .004, respectively). Multivariate analyses demonstrated that the co-index of the 2 SNPs was an independent prognostic factor for recurrence (P = .040). Similar results were obtained in the third cohort (N = 77). Furthermore, for HCC patients (all the 3 cohorts) exceeding Milan criteria, the co-index was a prognostic factor for recurrence and survival (P<.001 and P = .002, respectively).

CONCLUSIONS

Our study demonstrated first that genetic variations of rs894151 and rs12438080 in pretransplant plasma circulating DNA are promising prognostic markers for tumor recurrence in HCC patients undergoing LT and identify a subgroup of patients who, despite having HCC exceeding Milan criteria, have a low risk of post-transplant recurrence.

Inhibitory effect of phytoglycoprotein (38 kDa) on expression of matrix metalloproteinase-9 in 12-O-tetradecanoylphorbol-13-acetate-treated HepG2cells

Tumor metastasis is one of the main causes of death for patients with malignant tumors. Matrix metalloproteinase-9 (MMP-9) has been implicated in the invasion and metastasis of various cancer cells. Firstly, glycoprotein isolated from Styrax japonica Siebold et al. Zuccarini (SJSZ) has a molecular weight with 38 kDa and consists of carbohydrate (57.64%) and protein (42.35%). In the composition of SJSZ glycoprotein, carbohydrate mostly consists of glucose (28.17%), galactose (21.85%) and mannose (2.62%) out of 52.64%, respectively. the protein consists of Trp (W, 7.01%), Pro (P, 6.72%), and Ile (I, 5.42%) out of 42.35% as three major amino acids, while total amount of other amino acids is 23.20%. The present study was designed to demonstrate whether or not SJSZ glycoprotein prevents the activity of MMP-9 as a metastasis factor against 12-O-tetradecanoylphorbol-13-acetate (TPA). The study evaluated intracellular ROS and the phosphorylation of mitogen-activated protein kinases (MAPKs: extracellular signal-regulated kinase [ERK], stress-activated protein kinase/c-Jun N-terminal kinase [SAPK/JNK] and the p38 MAPK), the activities of transcriptional factors (nuclear factor [NF]-κB and activator protein [AP]-1), cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and MMP-9 in TPA-induced HepG2 cells using the Western blotting analysis, EMSA and gelatin zymography. The results showed that SJSZ glycoprotein (50 μg/ml) suppressed the production of intracellular ROS and the phosphorylation of ERK, JNK and p38 MAPK, as well as the activities of transcriptional factors (NF-κB and AP-1), COX-2, iNOS, and MMP-9 in TPA-induced HepG2 cells. Taking the aforementioned results into account together, this present study suggested that SJSZ glycoprotein might be a potent anti-metastatic agent that suppresses MMP-9 enzymatic activity via the NF-κB and AP-1 signaling pathway.

The tumor microenvironment in hepatocellular carcinoma: current status and therapeutic targets

A growing body of literature highlights the cross-talk between tumor cells and the surrounding peri-tumoral stroma as a key modulator of the processes of hepatocarcinogenesis, epithelial mesenchymal transition (EMT), tumor invasion and metastasis. The tumor microenvironment can be broadly classified into cellular and non-cellular components. The major cellular components include hepatic stellate cells, fibroblasts, immune, and endothelial cells. These cell types produce the non-cellular components of the tumor stroma, including extracellular matrix (ECM) proteins, proteolytic enzymes, growth factors and inflammatory cytokines. The non-cellular component of the tumor stroma modulates hepatocellular carcinoma (HCC) biology by effects on cancer signaling pathways in tumor cells and on tumor invasion and metastasis. Global gene expression profiling of HCC has revealed that the tumor microenvironment is an important component in the biologic and prognostic classification of HCC. There are substantial efforts underway to develop novel drugs targeting tumor-stromal interactions. In this review, we discuss the current knowledge about the role of the tumor microenvironment in pathogenesis of HCC, the role of the tumor microenvironment in the classification of HCC and efforts to develop treatments targeting the tumor microenvironment.

Epithelial-mesenchymal transitions and hepatocarcinogenesis

Epithelial-mesenchymal transitions (EMTs) are believed to play a role in invasion and metastasis of many types of tumors. In this issue of the JCI, Chen et al. show that a gene that has been associated with aggressive biology in hepatocellular carcinomas initiates a molecular cascade that results in EMT.

Doxorubicin induces apoptosis in H9c2 cardiomyocytes: role of overexpressed eukaryotic translation initiation factor 5A

The cardiotoxicity of doxorubicin limits its clinical use in the treatment of a variety of solid tumors and malignant hematologic disease. Although the mechanism by which it causes cardiac injury is not yet known, apoptosis has been regarded as one of mechanisms underlying the cardiotoxic effects of doxorubicin. Eukaryotic translation initiation factor 5A (eIF5A) is a ubiquitously expressed multifunctional protein that interacts with a range of ligands and is implicated in cell signaling. However, there has been no direct evidence for the critical involvement of eIF5A in doxorubicin-induced apoptosis. Overexpression of eIF5A induced by doxorubicin in cardiomyocyte leads to growth perturbation along with initiation of apoptosis. Overexpression of eIF5A results in a gradual increase in reactive oxygen species (ROS) generation. This mitochondrial dysfunction is due to a gradual increase in ROS generation in eIF5A-overexpressing H9c2 cells. Along with ROS generation, increased Ca(2+) influx in mitochondria leads to loss of the mitochondrial transmembrane potential, release of cytochrome-c, and caspase activation. However, small interfering RNA (siRNA)-mediated suppression of eIF5A results in inhibition of apoptosis. Interestingly, upon overexpression of eIF5A induced by doxorubicin, cell apoptosis was shown to be significantly inhibited when cells were treated with SB202190 (p38 mitogen-activated protein kinase inhibitor) and SP600125 (anti-c-Jun N-terminal kinase inhibitor) for 18 h. The reduction in oxidant generation and reduction in the apoptotic cell population were the results of the disruption of eIF5A expression, corroborating the hypothesis that excess ROS generation with overexpression of eIF5A induced by doxorubicin leads to apoptosis due to the accumulation of eIF5A.