Gene expression profile of primary gastric cancer: towards the prediction of lymph node status

Exosomal miR-21 determines lung-to-brain metastasis specificity through the DGKB/ERK axis within the tumor microenvironment

BACKGROUND

Brain metastasis affects 20-40 % of lung cancer patients, severely diminishing their quality of life. This research focuses on miR-21, overexpressed in these patients and inversely associated with DGKB in the ERK/STAT3 pathway, suggesting a dysregulated pathway with therapeutic potential.

AIMS

The objective was to investigate miR-21's role in lung cancer patients with brain metastases and whether targeting this pathway could improve treatment outcomes. We also examined the miR-21 content in tumor spheres-derived extracellular vesicles (EVs) and their influence on ERK/STAT3 signaling and metastasis.

MATERIALS AND METHODS

Tumor spheres were created from metastatic lung cancer cells. We studied miR-21 levels in these spheres, their impact on macrophage polarization, and the transition of nonmetastatic lung cancer cells. Furthermore, we analyzed miR-21 content in EVs derived from these spheres and their effect on ERK/STAT3 signaling and metastasis potential.

KEY FINDINGS

We found tumor spheres had high miR-21 levels, promoting macrophage polarization and, epithelial-mesenchymal transition. These spheres-derived EVs, enriched with miR-21, accelerated ERK/STAT3 signaling and metastasis. Silencing miR-21 and inhibiting ERK signaling with ulixertinib notably mitigated these effects. Moreover, ulixertinib reduced brain metastasis incidence and increased survival in a mouse model and led to reduced tumor sphere generation and miR-21 levels in EVs.

SIGNIFICANCE

Our study highlights the exacerbation of lung-to-brain metastasis via miR-21-rich EV secretion. This underlines the therapeutic promise of targeting the miR-21/ERK/STAT3 pathway with ulixertinib for managing brain metastasis from lung cancer.

EIF5A2 promotes proliferation and invasion of intrahepatic cholangiocarcinoma cells

PURPOSE

Intrahepatic cholangiocarcinoma (ICC) can invade and metastasize. EIF5A2 is involved in the invasive metastatic process of several digestive malignancies. However, its role in ICC is yet to be elucidated.

METHODS

Immunohistochemistry (IHC) and Western blot (WB) were used to detect the level of EIF5A2 in the tumor specimens of ICC patients and evaluate the correlation between its expression and clinicopathological characteristics. The significance of EIF5A2 in the prognosis of ICC patients was further evaluated by Kaplan-Meier and Cox regression analysis. In addition, CCK-8, EdU, Transwell invasion, and scratch assays were utilized to detect tumor cell proliferation, invasion, and metastasis. Furthermore, the role of EIF5A2 in ICC cells was evaluated after modification of EIF5A2 expression.

RESULTS

The level of EIF5A2 protein was significantly higher in ICC than in adjacent tissues. This high expression in the tumor samples was significantly associated with malignant phenotypes, such as lymph node metastasis (LNM), microvascular or bile duct invasion, and poor differentiation. ICC patients with high expression of EIF5A2 had short overall survival and a high cumulative recurrence rate. The multifactorial analysis showed that EIF5A2 is an independent prognostic marker. Furthermore, high levels of EIF5A2 may activate the PI3K/AKT/mTOR signaling pathway and upregulate Cyclin D1, Cyclin D3, MMP2, and MMP9 to promote ICC cell proliferation, migration, and invasion.

CONCLUSION

The current study found that EIF5A2 promotes ICC progression and is a prognostic biomarker and candidate therapeutic target for ICC patients.

A genomic-clinicopathologic Nomogram for the preoperative prediction of lymph node metastasis in gastric cancer

BACKGROUND

Preoperative evaluation of lymph node (LN) state is of pivotal significance for informing therapeutic decisions in gastric cancer (GC) patients. However, there are no non-invasive methods that can be used to preoperatively identify such status. We aimed at developing a genomic biosignature based model to predict the possibility of LN metastasis in GC patients.

METHODS

We used the RNA profile retrieving strategy and performed RNA expression profiling in a large GC cohort (GSE62254, n = 300) from Gene Expression Ominus (GEO). In the exploratory stage, 300 GC patients from GSE62254 were involved and the differentially expressed RNAs (DERs) for LN-status were determined using the R software. GC samples in GSE62254 were randomly allocated into a learning set (n = 210) and a verification set (n = 90). By using the Least absolute shrinkage and selection operator (LASSO) regression approach, a set of 23-RNA signatures were established and the signature based nomogram was subsequently built for distinguishing LN condition. The diagnostic efficiency, as well as the clinical performance of this model were assessed using the decision curve analysis (DCA). Metascape was used for bioinformatic analysis of the DERs.

RESULTS

Based on the genomic signature, we established a nomogram that robustly distinguished LN status in the learning (AUC = 0.916, 95% CI 0.833-0.999) and verification sets (AUC = 0.775, 95% CI 0.647-0.903). DCA demonstrated the clinical value of this nomogram. Functional enrichment analysis of the DERs was performed using bioinformatics methods which revealed that these DERs were involved in several lymphangiogenesis-correlated cascades.

CONCLUSIONS

In this study, we present a genomic signature based nomogram that integrates the 23-RNA biosignature based scores and Lauren classification. This model can be utilized to estimate the probability of LN metastasis with good performance in GC. The functional analysis of the DERs reveals the prospective biogenesis of LN metastasis in GC.

Prognostic Relevance of the Eighth Edition of TNM Classification for Resected Perihilar Cholangiocarcinoma

OBJECTIVES

In our study, we evaluated and compared the prognostic value and performance of the 6th, 7th, and 8th editions of the American Joint Committee on Cancer (AJCC) staging system in patients undergoing surgery for perihilar cholangiocarcinoma (PHC).

METHODS

Patients undergoing liver surgery with curative intention for PHC between 2002 and 2019 were identified from a prospective database. Histopathological parameters and stage of the PHC were assessed according to the 6th, 7th, and 8th editions of the tumor node metastasis (TNM) classification. The prognostic accuracy between staging systems was compared using the area under the receiver operating characteristic curve (AUC) model.

RESULTS

Data for a total of 95 patients undergoing liver resection for PHC were analyzed. The median overall survival time was 21 months (95% CI 8.1-33.9), and the three- and five-year survival rates were 46.1% and 36.2%, respectively. Staging according to the 8th edition vs. the 7th edition resulted in the reclassification of 25 patients (26.3%). The log-rank p-values for the 7th and 8th editions were highly statistically significant (p ≤ 0.01) compared to the 6th edition (p = 0.035). The AJCC 8th edition staging system showed a trend to better discrimination, with an AUC of 0.69 (95% CI: 0.52-0.84) compared to 0.61 (95% CI: 0.51-0.73) for the 7th edition. Multivariate survival analysis revealed male gender, age >65 years, positive resection margins, presence of distant metastases, poorly tumor differentiation, and lymph node involvement, such as no caudate lobe resection, as independent predictors of poor survival (p < 0.05).

CONCLUSIONS

In the current study, the newly released 8th edition of AJCC staging system showed no significant benefit compared to the previous 7th edition in predicting the prognosis of patients undergoing liver resection for perihilar cholangiocarcinoma. Further research may help to improve the prognostic value of the AJCC staging system for PHC-for instance, by identifying new prognostic markers or staging criteria, which may improve that individual patient's outcome.

Systematic Review of Prognostic Gene Signature in Gastric Cancer Patients

Gastric cancer (GC) is the second leading cause of cancer mortality and remains the fourth common cancer worldwide. The effective and feasible methods for predicting the possible outcomes for GC patients are still lacking. While genetic profiling might be suitable in some way, the application of gene expression signatures has been show to be a robust tool. Here, by performing a comprehensive search in PubMed, we provided an up-to-date summary of 39 prognostic gene signatures for GC patients, and described the processing procedure of the selection, calculation and construction of gene signature. We also reviewed current web tools including PROGgene and SurvExpress that can be used to analyze the prognostic value of multiple genes for GC. This review will aid in comprehensive understanding of the current prognostic gene signatures to accurately predict the outcome of GC patients, and may guide the future clinical management when the reliability of these signatures is validated in clinics.

Expression patterns of seven key genes, including β-catenin, Notch1, GATA6, CDX2, miR-34a, miR-181a and miR-93 in gastric cancer

Gastric cancer (GC) is one of the most prevalent cancers and a major cause of cancer related mortality worldwide. Incidence of GC is affected by various factors, including genetic and environmental factors. Despite extensive research has been done for molecular characterization of GC, it remains largely unknown. Therefore, further studies specially conducted among various ethnicities in different geographic locations, are required to know the precise molecular mechanisms leading to tumorigenesis and progression of GC. The expression patterns of seven candidate genes, including β-catenin, Notch1, GATA6, CDX2, miR-34a, miR-181a, and miR-93 were determined in 24 paired GC tissues and corresponding non-cancerous tissues by quantitative Real-Time PCR. The association between the expression of these genes and clinicopathologic factors were also investigated. Our results demonstrated that overall mRNA levels of GATA6 were significantly decreased in the tumor samples in comparison with the non-cancerous tissues (median fold change (FC) = 0.3143; P = 0.0003). Overall miR-93 levels were significantly increased in the tumor samples relative to the non-cancerous gastric tissues (FC = 2.441; P = 0.0002). β-catenin mRNA expression showed a strong positive correlation with miR-34a (r = 0.5784; P = 0.0031), and miR-181a (r = 0.5652; P = 0.004) expression. miR-34a and miR-181a expression showed a significant positive correlation (r = 0.4862; P = 0.016). Moreover, lower expression of Notch1 was related to distant metastasis in GC patients with a borderline statistical significance (p = 0.0549). These data may advance our understanding of the molecular biology that drives GC as well as provide potential targets for defining novel therapeutic strategies for GC treatment.

Overexpression of EIF5A2 Predicts Poor Prognosis in Patients with Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common epithelial malignancy affecting the oral cavity, and it is especially significant in Asian countries. Patients diagnosed with OSCC have an unfavorable prognosis and additional prognostic markers would help improve therapeutic strategies. We sought to investigate the association between eukaryotic translation initiation factor 5A2 (EIF5A2) and epithelial–mesenchymal transition (EMT) markers as well as the prognostic significance of EIF5A2 in OSCC. The expression of EIF5A2 and EMT markers was measured through the immunohistochemical staining of specimens from 272 patients with OSCC. In addition, the correlation between different clinicopathological factors and EIF5A2 expression was analyzed. The prognostic role of EIF5A2 was then analyzed via Kaplan–Meier analysis and Cox proportional hazard models. Among the 272 patients, high EIF5A2 expression was significantly associated with an advanced N value (p = 0.008). High tumor expression of EIF5A2 was prone to the expression of low E-cadherin and high beta-catenin (p = 0.046 and p = 0.020, respectively). Patients with high EIF5A2 expression had unfavorable five-year survival rates as compared with those with low expression (49.7% and 67.3%, respectively). The prognostic role of EIF5A2 was further confirmed through multivariate analysis (hazard ratio = 1.714, 95% confidence interval: 1.134–2.590, p = 0.011). High EIF5A2 expression is associated with an advanced N value and EMT markers and may serve as a marker for an unfavorable prognosis in patients with OSCC.

Overexpression of EIF5A2 is associated with poor survival and aggressive tumor biology in gallbladder cancer

Gallbladder cancer (GBC) is a malignant tumor of the biliary tract. The main problem affecting the treatment of gallbladder cancer is late diagnosis and poor prognosis. EIF5A2 is one of two isoforms of the EIF5A family and is reported to be a new oncogenic protein in many human cancers. In this study, our results showed for the first time that EIF5A2 was overexpressed in GBC samples compared with non-tumor tissue. Overexpression of EIF5A2 was associated with lymph node metastasis, tumor differentiation, UICC (Union for International Cancer Control) staging, histological type, metastasis, and tumor size. Overexpression of EIF5A2 in gallbladder carcinoma tissues is also associated with poor prognosis in patients. The interference of EIF5A2 significantly inhibited the proliferation, cell cycle, migration and colony formation of GBC-SD cells in vitro. Our results suggest that EIF5A2 is a target oncogene and may be an important prognostic biomarker in the pathogenesis of gallbladder cancer.

Structure activity relationship studies on Amb639752: toward the identification of a common pharmacophoric structure for DGKα inhibitors

A series of analogues of Amb639752, a novel diacylglycerol kinase (DGK) inhibitor recently discovered by us via virtual screening, have been tested. The compounds were evaluated as DGK inhibitors on α, θ, and ζ isoforms, and as antagonists on serotonin receptors. From these assays emerged two novel compounds, namely 11 and 20, which with an IC₅₀ respectively of 1.6 and 1.8 µM are the most potent inhibitors of DGKα discovered to date. Both compounds demonstrated the ability to restore apoptosis in a cellular model of X-linked lymphoproliferative disease as well as the capacity to reduce the migration of cancer cells, suggesting their potential utility in preventing metastasis. Finally, relying on experimental biological data, molecular modelling studies allow us to set a three-point pharmacophore model for DGK inhibitors.

Eukaryotic initiation factor 5A2 and human digestive system neoplasms

Eukaryotic initiation factor 5A2 (eIF5A2), as one of the two isoforms in the family, is reported to be a novel oncogenic protein that is involved in multiple aspects of many types of human cancer. Overexpression or gene amplification of EIF5A2 has been demonstrated in many cancers. Accumulated evidence shows that eIF5A2 initiates tumor formation, enhances cancer cell growth, increases cancer cell metastasis, and promotes treatment resistance through multiple means, including inducing epithelial–mesenchymal transition, cytoskeletal rearrangement, angiogenesis, and metabolic reprogramming. Expression of eIF5A2 in cancer correlates with poor survival, advanced disease stage, as well as metastasis, suggesting that eIF5A2 function is crucial for tumor development and maintenance but not for normal tissue homeostasis. All these studies suggest that eIF5A2 is a useful biomarker in the prediction of cancer prognosis and serves as an anticancer molecular target. This review focuses on the expression, subcellular localization, post-translational modifications, and regulatory networks of eIF5A2, as well as its biochemical functions and evolving clinical applications in cancer, especially in human digestive system neoplasms.

A genomewide transcriptomic approach identifies a novel gene expression signature for the detection of lymph node metastasis in patients with early stage gastric cancer

Background

Although identification of lymph node (LN) metastasis is a well-recognized strategy for improving outcomes in patients with gastric cancer (GC), currently there is lack of availability of adequate molecular biomarkers that can identify such metastasis. Herein we have developed a robust gene-expression signature for detecting LN metastasis in early stage GC by using a transcriptome-wide biomarker discovery and subsequent validation in multiple clinical cohorts.

Methods

A total of 532 patients with pathological T1 and T2 GC from 4 different cohorts were analyzed. Two independent datasets (n = 96, and n = 188) were used to establish a gene signature for the identification of LN metastasis in GC patients. The diagnostic performance of our gene-expression signature was subsequently assessed in two independent clinical cohorts using qRT-PCR assays (n = 101, and n = 147), and subsequently compared against conventional tumor markers and image-based diagnostics.

Findings

We established a 15-gene signature by analyzing multiple high throughput datasets, which robustly distinguished LN status in both training (AUC = 0.765, 95% CI 0.667–0.863) and validation cohorts (AUC = 0.742, 95% CI 0.630–0.852). Notably, the 15-gene signature was significantly superior compared to the conventional tumor markers, CEA (P = .04) and CA19–9 (P = .005), as well as computed tomography-based imaging (P = .04).

Interpretation

We have established and validated a 15-gene signature for detecting LN metastasis in GC patients, which offers a robust diagnostic tool for potentially improving treatment outcomes in gastric cancer patients.

Fund

NIH: CA72851, CA181572, CA14792, CA202797, CA187956; CPRIT: RP140784: Baylor Sammons Cancer Center polot grants (AG), VPRT: 9610337, CityU 21101115, 11102317, 11103718; JCYJ20170307091256048 (XW).

Diacylglycerol Kinase Malfunction in Human Disease and the Search for Specific Inhibitors

The diacylglycerol kinases (DGKs) are master regulator kinases that control the switch from diacylglycerol (DAG) to phosphatidic acid (PA), two lipids with important structural and signaling properties. Mammalian DGKs distribute into five subfamilies that regulate local availability of DAG and PA pools in a tissue- and subcellular-restricted manner. Pharmacological manipulation of DGK activity holds great promise, given the critical contribution of specific DGK subtypes to the control of membrane structure, signaling complexes, and cell-cell communication. The latest advances in the DGK field have unveiled the differential contribution of selected isoforms to human disease. Defects in the expression/activity of individual DGK isoforms contribute substantially to cognitive impairment, mental disorders, insulin resistance, and vascular pathologies. Abnormal DGK overexpression, on the other hand, confers the acquisition of malignant traits including invasion, chemotherapy resistance, and inhibition of immune attack on tumors. Translation of these findings into therapeutic approaches will require development of methods to pharmacologically modulate DGK functions. In particular, inhibitors that target the DGKα isoform hold particular promise in the fight against cancer, on their own or in combination with immune-targeting therapies.

Prognostic value of AIB1 and EIF5A2 in intravesical recurrence after surgery for upper tract urothelial carcinoma

Objectives

The aim of this study was to investigate the prognostic effect of amplified in AIB1 and EIF5A2 expression on postoperative intravesical recurrence for upper urinary tract urothelial carcinoma (UTUC) and improve postoperative risk stratification and prediction of intravesical chemotherapy benefit.

Materials and methods

We evaluated immunohistochemical expression of AIB1 and EIF5A2 in 109 UTUC patients to determine the predictive significance in intravesical recurrence. A prognostic model was developed based on univariate and multivariate analyses.

Results

Intravesical recurrence occurred in 18 out of the 109 (16.5%) patients during the follow-up period. Significant associations of high expression of AIB1 and EIF5A2 with shortened bladder recurrence interval (median: 24 months vs 46 months, P=0.021; 28 months vs 39 months, P=0.002) were demonstrated. In different subsets of UTUC patients, high expression of AIB1 was a prognostic indicator in high grade (P=0.006) and pT2–4 (P=0.007), and high expression of EIF5A2 for high grade (P=0.014), pT2–4 (P=0.002) and pN0 (P=0.009). Moreover, in multivariate analysis, AIB1 and EIF5A2 expression (P=0.034 and 0.022, respectively) together with pN stage (P=0.009) provided significant independent predictors for intravesical recurrence after surgery for UTUC. Surgical approach with radical nephroureterectomy (RNU) was an informative factor toward good oncologic outcomes for intravesical recurrence (P=0.056). Based on a prognostic model with these factors, patients with UTUC were classified into the low-risk group and the high-risk group. In a subset analysis, the patients in the high-risk group were found to have a favorable response to intravesical chemotherapy (P=0.047). A nomogram based on the multivariate analysis was developed to predict intravesical recurrence accurately and guide postoperative intravesical instillations. The concordance index (c-index) of this model was 0.806.

Conclusion

High expression of AIB1 and EIF5A2 were independent predictors for intravesical recurrence after RNU and might be able to predict which patients benefit from postoperative intravesical chemotherapy.

Prognostic value of a 25-gene assay in patients with gastric cancer after curative resection

This study aimed to develop and validate a practical, reliable assay for prognosis and chemotherapy benefit prediction compared with conventional staging in Gastric cancer (GC). Twenty-three candidate genes with significant correlation between quantitative hybridization and microarray results plus 2 reference genes were selected to form a 25-gene prognostic classifier, which can classify patients into 3 distinct groups of different risk of mortality obtained by analyzing microarray data from 78 frozen tumor specimens. The 25-gene assay was associated with overall survival in both training (P = 0.017) and testing cohort (P = 0.005) (462 formalin-fixed paraffin-embedded samples). The risk prediction in stages I + II is significantly better than that in stages III. Analysis demonstrated that this 25-gene signature is an independent prognostic predictor and show higher prognostic accuracy than conventional TNM staging in early stage patients. Moreover, only high-risk patients in stage I + II were found benefit from adjuvant chemotherapy (P = 0.043), while low-risk patients in stage III were not found benefit from adjuvant chemotherapy. In conclusion, our results suggest that this 25-gene assay can reliably identify patients with different risk for mortality after surgery, especially for stage I + II patients, and might be able to predict patients who benefit from chemotherapy.

Diacylglycerol kinases in cancer

Diacylglycerol kinases (DGK) are a family of enzymes that catalyze the transformation of diacylglycerol into phosphatidic acid. In T lymphocytes, DGKα and ζ limit the activation of the PLCγ/Ras/ERK axis, providing a critical checkpoint to inhibit T cell responses. Upregulation of these isoforms limits Ras activation, leading to hypo-responsive, anergic states similar to those caused by tumors. Recent studies have identified DGKα upregulation in tumor lymphocyte infiltrates, and cells from DGKα and ζ deficient mice show enhanced antitumor activity, suggesting that limitation of DAG based signals by DGK is used by tumors to evade immune attack. DGKα expression is low or even absent in other healthy cells like melanocytes, hepatocytes or neurons. Expression of this isoform, nevertheless is upregulated in melanoma, hepatocarcinoma and glioblastoma where DGKα contributes to the acquisition of tumor metastatic traits. A model thus emerges where tumor milieu fosters DGKα expression in tumors as well as in tumor infiltrating lymphocytes with opposite consequences. Here we review the mechanisms and targets that facilitate tumor "addiction" to DGKα, and discuss its relevance in the more advanced forms of cancer for tumor immune evasion. A better knowledge of this function offers a new perspective in the search of novel approaches to prevent inhibition of immune attack in cancer. Part of the failure in clinical progress may be attributed to the complexity of the tumor/T lymphocyte interaction. As they develop, tumors use a number of mechanisms to drive endogenous, tumor reactive T cells to a general state of hyporesponsiveness or anergy. A better knowledge of the molecular mechanisms that tumors use to trigger T cell anergic states will greatly help in the advance of immunotherapy research.

Eukaryotic translation initiation factor 5A2 promotes metabolic reprogramming in hepatocellular carcinoma cells

Reprogramming of intracellular metabolism is common in liver cancer cells. Understanding the mechanisms of cell metabolic reprogramming may present a new basis for liver cancer treatment. In our previous study, we reported that a novel oncogene eukaryotic translation initiation factor 5A2 (EIF5A2) promotes tumorigenesis under hypoxic condition. Here, we aim to investigate the role of EIF5A2 in cell metabolic reprogramming during hepatocellular carcinoma (HCC) development. In this study, we reported that the messenger RNA (mRNA) level of EIF5A2 was upregulated in 59 of 105 (56.2%) HCC clinical samples (P = 0.015), and EIF5A2 overexpression was significantly associated with shorter survival time of patients with HCC (P = 0.021). Ectopic expression of EIF5A2 in HCC cell lines significantly promoted cell growth and accelerated glucose utilization and lipogenesis rates. The high rates of glucose uptake and lactate secretion conferred by EIF5A2 revealed an abnormal activity of aerobic glycolysis in HCC cells. Several key enzymes involved in glycolysis including glucose transporter type 1 and 2, hexokinase 2, phosphofructokinase liver type, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase M2 isoform, phosphoglycerate mutase 1 and lactate dehydrogenase A were upregulated by overexpression of EIF5A2. Moreover, EIF5A2 showed positive correlations with FASN and ACSS2, two key enzymes involved in the fatty acid de novo biosynthetic pathway, at both protein and mRNA levels in HCC. These results indicated that EIF5A2 may regulate fatty acid de novo biosynthesis by increasing the uptake of acetate. In conclusion, our findings demonstrate that EIF5A2 has a critical role in HCC cell metabolic reprogramming and may serve as a prominent novel therapeutic target for liver cancer treatment.

Autoantibody Response to ZRF1 and KRR1 SEREX Antigens in Patients with Breast Tumors of Different Histological Types and Grades

Purpose. To investigate a frequency of antibody response to SEREX-identified medullary breast carcinoma autoantigens ZRF1 and KRR1 in sera of breast cancer patients taking into account clinical and molecular characteristics of tumors for opening of new perspectives in creation of minimally invasive immunological tests for cancer diagnostics. Methods. Enzyme-linked immunosorbent assay and bioinformatics analysis. Results. Increased frequency of antibody response was found in sera of breast cancer patients to ZRF and KRR1 antigens. The antibody response to these antigens was higher in sera of patients with invasive ductal carcinoma than in sera of patients with other histological types of breast tumors. Moreover, more frequent antibody response to ZRF antigen was found in sera of patients with less aggressive tumors. The sequence analysis of ZRF1 antigen SEREX clones obtained from cDNA libraries of different tumors demonstrates that they encode different protein isoforms. Conclusion. Tumor-associated antigens KRR1 and ZRF1 and their cognate autoantibodies could be considered as potential molecular markers of breast cancer which need to be further investigated.

Prognostic significance of the expression of nuclear eukaryotic translation initiation factor 5A2 in human melanoma

Eukaryotic translation initiation factor 5A2 (EIF5A2) expression is upregulated in various cancers. The present authors previously demonstrated that cytoplasmic EIF5A2 expression increases with melanoma progression and inversely correlates with patient survival. Other studies have suggested that nuclear EIF5A2 may also play a role in oncogenesis. The present study used immunohistochemistry and tissue microarray with a large number of melanocytic lesions (n=459) and demonstrated that nuclear EIF5A2 expression was significantly upregulated between common acquired nevi, dysplastic nevi and primary melanomas, and between primary melanomas and metastatic melanomas. Nuclear EIF5A2 expression was inversely associated with overall and disease-specific 5-year survival rate for all (P<0.001) and primary (P=0.014 and P=0.015, respectively) melanoma patients. Nuclear EIF5A2 expression was directly associated with melanoma thickness (P=0.036) and American Joint Committee on Cancer staging (P<0.001), which suggests the possible role of nuclear EIF5A2 in melanoma cell invasion. Subsequently, the present study investigated the association between the expression of nuclear EIF5A2 and matrix metalloproteinase-2 (MMP-2), which is an important factor for promoting cancer cell invasion. Nuclear EIF5A2 and a strong MMP-2 expression were directly associated, and their concurrent expression was significantly associated with a poorer overall and disease-specific 5-year survival rate for all and primary melanoma patients. Nuclear and cytoplasmic EIF5A2 expression were also demonstrated to be significantly associated, and simultaneous expression of the two forms of EIF5A2 was significantly associated with poor overall and disease-specific 5-year survival rates for all and primary melanoma patients. Multivariate Cox regression analysis revealed that nuclear EIF5A2 expression alone and in combination with cytoplasmic EIF5A2 expression was an adverse independent prognostic factor for all and primary melanoma patients. In conclusion, the present study for the first time, to the best of our knowledge, demonstrated that nuclear EIF5A2 expression is an independent prognostic marker in melanoma, and revealed its role in melanoma progression and patient survival. Therefore, nuclear EIF5A2 may have the potential to serve as a therapeutic marker for melanoma.

Identification and validation of AIB1 and EIF5A2 for noninvasive detection of bladder cancer in urine samples

We previously demonstrated that amplified in breast cancer 1 (AIB1) and eukaryotic initiation factor 2 (EIF5A2) overexpression was an independent predictor of poor clinical outcomes for patients with bladder cancer (BCa). In this study, we evaluated the usefulness of AIB1 and EIF5A2 alone and in combination with nuclear matrix protein 22 (NMP22) as noninvasive diagnostic tests for BCa. Using urine samples from 135 patients (training set, controls [n = 50] and BCa [n = 85]), we detected the AIB1, EIF5A2, and NMP22 concentrations using enzyme-linked immunosorbent assay. We applied multivariate logistic regression analysis to build a model based on the three biomarkers for BCa diagnosis. The diagnostic accuracy of the three biomarkers and the model were assessed and compared by the area under the curve (AUC) of the receiver operating characteristic. We validated the diagnostic accuracy of these biomarkers and the model in an independent validation cohort of 210 patients. In the training set, urinary concentrations of AIB1, EIF5A2, and NMP22 were significantly elevated in BCa. The AUCs of AIB1, EIF5A2, NMP22, and the model were 0.846, 0.761, 0.794, and 0.919, respectively. The model had the highest diagnostic accuracy when compared with AIB1, EIF5A2, or NMP22 (p < 0.05 for all). The model had 92% sensitivity and 92% specificity. We obtained similar results in the independent validation cohort. AIB1 and EIF5A2 show promise for the noninvasive detection of BCa. The model based on AIB1, EIF5A2, and NMP22 outperformed each of the three individual biomarkers for detecting BCa.

Identifying Reproducible Molecular Biomarkers for Gastric Cancer Metastasis with the Aid of Recurrence Information

To precisely diagnose metastasis state is important for tailoring treatments for gastric cancer patients. However, the routinely employed radiological and pathologic tests for tumour metastasis have considerable high false negative rates, which may retard the identification of reproducible metastasis-related molecular biomarkers for gastric cancer. In this research, using three datasets, we firstly shwed that differentially expressed genes (DEGs) between metastatic tissue samples and non-metastatic tissue samples could hardly be reproducibly detected with a proper statistical control when the metastatic and non-metastatic samples were defined by TNM stage alone. Then, assuming that undetectable micrometastases are the prime cause for recurrence of early stage patients with curative resection, we reclassified all the “non-metastatic” samples as metastatic samples whenever the patients experienced tumour recurrence during follow-up after tumour resection. In this way, we were able to find distinct and reproducible DEGs between the reclassified metastatic and non-metastatic tissue samples and concordantly significant DNA methylation alterations distinguishing metastatic tissues and non-metastatic tissues of gastric cancer. Our analyses suggested that the follow-up recurrence information for patients should be employed in the research of tumour metastasis in order to decrease the confounding effects of false non-metastatic samples with undetected micrometastases.

Expression of eukaryotic translation initiation factor 5A-2 (eIF5A-2) associated with poor survival in gastric cancer

Altered expression of eukaryotic translation initiation factor 5A-2 (eIF5A-2) was associated with human carcinogenesis and progression. This study assessed eIF5A-2 expression in gastric cancer tissues for association with clinicopathological parameters and survival of patients. A total of 436 gastric cancer tissues and 92 normal mucosal blocks were collected for construction of tissue microarrays and immunohistochemical assessment of eIF5A-2 expression. The data were statistically analyzed for association with clinicopathological factors and survival of patients. Immunohistochemical data showed that eIF5A-2 protein was highly expressed in gastric cancer tissues (p < 0.001). Upregulated expression of eIF5A-2 protein was associated with tumor Lauren classification, size, location, invasion, TNM stages, and lymph node and distant metastases. The 3- and 5-year cumulative survival rates of these 436 patients were 88.5 and 58.1 %, respectively. In contrast, the mean survival time of patients with increased tumor eIF5A-2 was 30.22 ± 1.23 vs. 51.29 ± 0.86 months for those with low tumor eIF5A-2 (p < 0.001). Multivariate analysis showed that eIF5A-2 expression and related tumor parameters were independent indicators of overall survival in gastric cancer patients. In conclusion, the current study indicates that overexpression of eIF5A-2 protein was associated with poor overall survival of gastric cancer patients.

Molecular classification and prediction in gastric cancer

Gastric cancer, a highly heterogeneous disease, is the second leading cause of cancer death and the fourth most common cancer globally, with East Asia accounting for more than half of cases annually. Alongside TNM staging, gastric cancer clinic has two well-recognized classification systems, the Lauren classification that subdivides gastric adenocarcinoma into intestinal and diffuse types and the alternative World Health Organization system that divides gastric cancer into papillary, tubular, mucinous (colloid), and poorly cohesive carcinomas. Both classification systems enable a better understanding of the histogenesis and the biology of gastric cancer yet have a limited clinical utility in guiding patient therapy due to the molecular heterogeneity of gastric cancer. Unprecedented whole-genome-scale data have been catalyzing and advancing the molecular subtyping approach. Here we cataloged and compared those published gene expression profiling signatures in gastric cancer. We summarized recent integrated genomic characterization of gastric cancer based on additional data of somatic mutation, chromosomal instability, EBV virus infection, and DNA methylation. We identified the consensus patterns across these signatures and identified the underlying molecular pathways and biological functions. The identification of molecular subtyping of gastric adenocarcinoma and the development of integrated genomics approaches for clinical applications such as prediction of clinical intervening emerge as an essential phase toward personalized medicine in treating gastric cancer.

Diacylglycerol kinase α promotes 3D cancer cell growth and limits drug sensitivity through functional interaction with Src

Diacylglycerol kinase (DGK)α converts diacylglycerol to phosphatidic acid. This lipid kinase sustains survival, migration and invasion of tumor cells, with no effect over untransformed cells, suggesting its potential as a cancer-specific target. Nonetheless the mechanisms that underlie DGKα specific contribution to cancer survival have not been elucidated. Using three-dimensional (3D) colon and breast cancer cell cultures, we demonstrate that DGKα upregulation is part of the transcriptional program that results in Src activation in these culture conditions. Pharmacological or genetic DGKα silencing impaired tumor growth in vivo confirming its function in malignant transformation. DGKα-mediated Src regulation contributed to limit the effect of Src inhibitors, and its transcriptional upregulation in response to PI3K/Akt inhibitors resulted in reduced toxicity. Src oncogenic properties and contribution to pharmacological resistance have been linked to its overactivation in cancer. DGKα participation in this central node helps to explain why its pharmacological inhibition or siRNA-mediated targeting specifically alters tumor viability with no effect on untransformed cells. Our results identify DGKα-mediated stabilization of Src activation as an important mechanism in tumor growth, and suggest that targeting this enzyme, alone or in combination with other inhibitors in wide clinical use, could constitute a treatment strategy for aggressive forms of cancer.

The translation factor eIF5A and human cancer

The eukaryotic initiation factor eIF5A is a translation factor that, unusually, has been assigned functions in both initiation and elongation. Additionally, it is implicated in transcription, mRNA turnover and nucleocytoplasmic transport. Two eIF5A isoforms are generated from distinct but related genes. The major isoform, eIF5A1, is considered constitutive, is abundantly expressed in most cells, and is essential for cell proliferation. The second isoform, eIF5A2, is expressed in few normal tissues but is highly expressed in many cancers and has been designated a candidate oncogene. Elevated expression of either isoform carries unfavorable prognostic implications for several cancers, and both have been advanced as cancer biomarkers. The amino acid hypusine, a presumptively unique eIF5A post-translational modification, is required for most known eIF5A functions and it renders eIF5A susceptible to inhibitors of the modification pathway as therapeutic targets. eIF5A has been shown to regulate a number of gene products specifically, termed the eIF5A regulon, and its role in translating proline-rich sequences has recently been identified. A model is advanced that accommodates eIF5A in both the initiation and elongation phases of translation. We review here the biochemical functions of eIF5A, the relationship of its isoforms with human cancer, and evolving clinical applications. This article is part of a Special Issue entitled: Translation and Cancer.

A functional biological network centered on XRCC3: a new possible marker of chemoradiotherapy resistance in rectal cancer patients

Preoperative chemoradiotherapy is widely used to improve local control of disease, sphincter preservation and to improve survival in patients with locally advanced rectal cancer. Patients enrolled in the present study underwent preoperative chemoradiotherapy, followed by surgical excision. Response to chemoradiotherapy was evaluated according to Mandard's Tumor Regression Grade (TRG). TRG 3, 4 and 5 were considered as partial or no response while TRG 1 and 2 as complete response. From pretherapeutic biopsies of 84 locally advanced rectal carcinomas available for the analysis, only 42 of them showed 70% cancer cellularity at least. By determining gene expression profiles, responders and non-responders showed significantly different expression levels for 19 genes (P < 0.001). We fitted a logistic model selected with a stepwise procedure optimizing the Akaike Information Criterion (AIC) and then validated by means of leave one out cross validation (LOOCV, accuracy = 95%). Four genes were retained in the achieved model: ZNF160, XRCC3, HFM1 and ASXL2. Real time PCR confirmed that XRCC3 is overexpressed in responders group and HFM1 and ASXL2 showed a positive trend. In vitro test on colon cancer resistant/susceptible to chemoradioterapy cells, finally prove that XRCC3 deregulation is extensively involved in the chemoresistance mechanisms. Protein-protein interactions (PPI) analysis involving the predictive classifier revealed a network of 45 interacting nodes (proteins) with TRAF6 gene playing a keystone role in the network. The present study confirmed the possibility that gene expression profiling combined with integrative computational biology is useful to predict complete responses to preoperative chemoradiotherapy in patients with advanced rectal cancer.

Overexpression of eukaryotic translation initiation factor 5A2 (EIF5A2) correlates with cell aggressiveness and poor survival in gastric cancer

Eukaryotic translation initiation factor 5A2 (EIF5A2) plays an important role in tumor progression and prognosis evaluation. However, little information is available about its potential role in gastric cancer. This study aimed to investigate the function of EIF5A2 in tumor progression and its potential mechanisms. EIF5A2 expression was measured in human gastric cancer cell lines, the immortalized gastric mucosal epithelial cell line (GES-1) and human gastric cancer tissues and knocked down by RNA interference or upregulated by EIF5A2 plasmid transfection. Cell proliferation, migration and invasion were assessed in vitro. The downstream targets of EIF5A2 were examined by western blotting. EIF5A2 and its potential target metastasis-associated protein 1 (MTA1) expression were examined in 160 pairs of human gastric cancer and adjacent non-tumor specimens using immunohistochemistry (IHC) staining, and its correlation with clinicopathological features and survival was investigated. Knockdown of EIF5A2 or MTA1 caused an apparent suppression of HGC27 cell proliferation, migration and invasion. After knockdown of EIF5A2 in HGC27 cells, E-cadherin levels were upregulated and vimentin, cyclin D1, cyclin D3, C-MYC and MTA1 levels were downregulated. Upregulation of EIF5A2 in MKN45 cells resulted in the converse. IHC results showed a positive correlation between EIF5A2 and MTA1 expression in gastric cancers (P<0.001). Both EIF5A2 and MTA1 overexpression were correlated with pT stage (P=0.018 and P=0.042), pN stage (P=0.037 and P=0.020) and lymphovascular invasion (P=0.016 and P=0.044). EIF5A2 or MTA1 overexpression was significantly associated with poor overall survival and disease-free survival (All P<0.05). Multivariate analyses identified EIF5A2 as an independent predictor for both overall survival (P=0.012) and disease-free survival (P=0.008) in gastric cancer patients. Our findings indicate that EIF5A2 upregulation plays an important oncogenic role in gastric cancer. EIF5A2 may represent a new predictor for poor survival and is a potential therapeutic target for gastric cancer.

Overexpression of Plasminogen Activator Inhibitor-1 in Advanced Gastric Cancer with Aggressive Lymph Node Metastasis

Purpose

The purpose of this study is to investigate differentially expressed genes using DNA microarray between advanced gastric cancer (AGC) with aggressive lymph node (LN) metastasis and that with a more advanced tumor stage but without LN metastasis.

Materials and Methods

Five sample pairs of gastric cancer tissue and normal gastric mucosa were taken from three patients with T3N3 stage (highN) and two with T4N0 stage (lowN). Data from triplicate DNA microarray experiments were analyzed, and candidate genes were identified using a volcano plot that showed ≥ 2-fold differential expression and were significant by Welch's t test (p < 0.05) between highN and lowN. Those selected genes were validated independently by reverse-transcriptase–polymerase chain reaction (RT-PCR) using five AGC patients, and tissue-microarray (TMA) comprising 47 AGC patients.

Results

CFTR, LAMC2, SERPINE2, F2R, MMP7, FN1, TIMP1, plasminogen activator inhibitor-1 (PAI-1), ITGB8, SDS, and TMPRSS4 were commonly up-regulated over 2-fold in highN. REG3A, CD24, ITLN1, and WBP5 were commonly down-regulated over 2-fold in lowN. Among these genes, overexpression of PAI-1 was validated by RT-PCR, and TMA showed 16.7% (7/42) PAI-1 expression in T3N3, but none (0/5) in T4N0 (p=0.393).

Conclusion

DNA microarray analysis and validation by RT-PCR and TMA showed that overexpression of PAI-1 is related to aggressive LN metastasis in AGC.

Molecular genetics of gastric adenocarcinoma in clinical practice

The molecular genetics of gastric carcinoma (GC) dictates their biology and clinical behavior. The two morphologically distinct types of gastric carcinoma by Lauren classification, i.e., intestinal and diffuse cell types, have a significant difference in clinical outcome. These two types of GC have different molecular pathogenetic pathways with unique genetic alterations. In addition to environmental and other etiologies, intestinal type GC is associated with Helicobacter pylori (H. pylori) infection and involves a multistep molecular pathway driving the normal epithelium to intestinal metaplasia, dysplasia, and malignant transformation by chromosomal and/or microsatellite instability (MSI), mutation of tumor suppressor genes, and loss of heterozygosity among others. Diffuse type shows no clear causal relationship with H. pylori infection, but is commonly associated with deficiency of cell-cell adhesion due to mutation of the E-cadherin gene (CDH1), and a manifestation of the hereditary gastric cancer syndrome. Thus, detection of CDH1 mutation or loss of expression of E-cadherin may aid in early diagnosis or screening of diffuse type GC. Detection of certain genetic markers, for example, MSI and matrix metalloproteinases, may provide prognostic information, particularly for intestinal type. The common genetic alterations may offer therapeutic targets for treatment of GC. Polymorphisms in Thymidylate synthase to metabolize 5-fluorouracil, glutathione S-transferase for degradation of Cisplatin, and amplification/overexpression of human epidermal growth factor receptor 2 targeted by monoclonal antibody Trastuzumab, are a few examples. P13K/Akt/mTOR pathway, c-Met pathways, epidermal growth factor receptor, insulin-like growth factor receptor, vascular endothelial growth factor receptor fibroblast growth factor receptor, and micro RNAs are several potential therapeutic biomarkers for GC under investigation.

EIF5A2 predicts outcome in localised invasive bladder cancer and promotes bladder cancer cell aggressiveness in vitro and in vivo

BACKGROUND

EIF5A2, eukaryotic translation initiation factor 5A2, is associated with several human cancers. In this study, we investigated the role of EIF5A2 in the metastatic potential of localised invasive bladder cancer (BC) and its underlying molecular mechanisms were explored.

METHODS

The expression pattern of EIF5A2 in localised invasive BC was determined by immunohistochemistry. In addition, the function of EIF5A2 in BC and its underlying mechanisms were elucidated with a series of in vitro and in vivo assays.

RESULTS

Overexpression of EIF5A2 was an independent predictor for poor metastasis-free survival of localised invasive BC patients treated with radical cystectomy. Knockdown of EIF5A2 inhibited BC cell migratory and invasive capacities in vitro and metastatic potential in vivo and reversed epithelial-mesenchymal transition (EMT), whereas overexpression of EIF5A2 promoted BC cells motility and invasiveness in vitro and metastatic potential in vivo and induced EMT. In addition, we found that EIF5A2 might activate TGF-β1 expression to induce EMT and drive aggressiveness in BC cells. EIF5A2 stabilized STAT3 and stimulated nuclear localisation of STAT3, which resulted in increasing enrichment of STAT3 onto TGF-β1 promoter to enhance the transcription of TGF-β1.

CONCLUSIONS

EIF5A2 overexpression predicts tumour metastatic potential in patients with localised invasive BC treated with radical cystectomy. Furthermore, EIF5A2 elevated TGF-β1 expression through STAT3 to induce EMT and promotes aggressiveness in BC.

Role of EIF5A2, a downstream target of Akt, in promoting melanoma cell invasion

BACKGROUND

Cutaneous melanoma is a life-threatening skin cancer because of its poorly understood invasive nature and high metastatic potential. This study examines the importance of eukaryotic translation initiation factor 5A2 (EIF5A2) in melanoma pathogenesis.

METHODS

We examined EIF5A2 expression in 459 melanocytic lesions using tissue microarray. In addition, melanoma cell lines were subjected to invasion and cell proliferation assays, zymography, FACS and real-time PCR to investigate the role of EIF5A2 in cancer progression.

RESULTS

Positive EIF5A2 staining increased from dysplastic naevi to primary melanomas (PMs; P=0.001), and further increased in metastatic melanomas (P=0.044). Eukaryotic translation initiation factor 5A2 expression was correlated with melanoma thickness (P<0.001) and was inversely correlated with the 5-year survival of PM patients especially those with tumour ≤2 mm thick. Strikingly, none of the latter died within 5 years in EIF5A2-negative staining group. Cox regression analysis revealed that EIF5A2 is an independent prognostic marker. Further, we found that EIF5A2 is a novel downstream target of phosphorylated Akt. Both melanoma cell invasion and MMP-2 activity increased and decreased with EIF5A2 overexpression and knockdown, respectively.

CONCLUSION

We for the first time showed that EIF5A2, as a target of PI3K/Akt, promotes melanoma cell invasion and may serve as a promising prognostic marker and a potential therapeutic target for melanoma.

A gene expression profile related to immune dampening in the tumor microenvironment is associated with poor prognosis in gastric adenocarcinoma

BACKGROUND

The TNM Classification of Malignant Tumours (TNM) staging system is the primary means of determining a prognosis for gastric adenocarcinoma (GC). However, tumor behavior in the individual patient is unpredictable and in spite of treatment advances, a classification of 'advanced stage' still portends a poor prognosis. Thus, further insights from molecular analyses are needed for better prognostic stratification and determination of new therapeutic targets.

METHODS

A total of fifty-one fresh frozen tumor samples from patients with histopathologically confirmed diagnoses of GC, submitted to surgery with curative intent, were included in the study. Total RNA was extracted from an initial group of fifteen samples matched for known prognostic factors, categorized into two subgroups, according to patient overall survival: poor (<24 months) or favorable (at or above 24 months), and hybridized to Affymetrix Genechip human genome U133 plus 2.0 for genes associated with prognosis selection. Thirteen genes were selected for qPCR validation using those initial fifteen samples plus additional thirty-six samples.

RESULTS

A total of 108 genes were associated with poor prognosis, independent of tumor staging. Using systems biology, we suggest that this panel reflects the dampening of immune/inflammatory response in the tumor microenvironment level and a shift to Th2/M2 activity. A gene trio (OLR1, CXCL11 and ADAMDEC1) was identified as an independent marker of prognosis, being the last two markers validated in an independent patient cohort.

CONCLUSIONS

We determined a panel of three genes with prognostic value in gastric cancer, which should be further investigated. A gene expression profile suggestive of a dysfunctional inflammatory response was associated with unfavorable prognosis.

Roles of eukaryotic initiation factor 5A2 in human cancer

Eukaryotic initiation factor 5A (eIF5A), the only known cellular protein containing the amino acid hypusine, is an essential component of translation elongation. eIF5A2, one of the two isoforms in the eIF5A family, is reported to be a novel oncogenic protein in many types of human cancer. Both in vitro and in vivo studies showed that eIF5A2 could initiate tumor formation, enhance cancer cell growth, and increase cancer cell motility and metastasis by inducing epithelial-mesenchymal transition. Accumulatied evidence suggests that eIF5A2 is a useful biomarker in the prediction of cancer prognoses and serves as an anticancer molecular target. In this review, we will focus on updating current knowledge of the EIF5A2 gene in human cancers. The molecular mechanisms of EIF5A2 related to tumorigenesis will also be discussed.

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.

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.

Protein predictive signatures for lymph node metastasis of gastric cancer

Lymph node status remains one of most crucial indicators of gastric cancer prognosis and treatment planning. Current imaging methods have limited accuracy in predicting lymph node metastasis. We sought to identify protein markers in primary gastric cancer and to define a risk model to predict lymph node metastasis. The Protein Pathway Array (PPA) (initial selection) and Western blot (confirmation) were used to assess the protein expression in a total of 190 freshly frozen gastric cancer samples. The protein expression levels were compared between samples with lymph node metastasis (n = 73) and those without lymph node metastasis (n = 57) using PPA. There were 27 proteins differentially expressed between lymph node positive samples and lymph node negative samples. Five proteins (Factor XIII B, TFIIH p89, ADAM8, COX-2 and CUL-1) were identified as independent predictors of lymph node metastasis. Together with vascular/lymphatic invasion status, a risk score model was established to determine the risk of lymph node metastasis for each individual gastric cancer patient. The ability of this model to predict lymph node metastasis was further confirmed in a second cohort of gastric cancer patients (33 with and 27 without lymph node metastasis) using Western blot. This study indicated that some proteins differentially expressed in gastric cancer can be selected as clinically useful biomarkers. The risk score model is useful for determining patients' risk of lymph node metastasis and prognosis.

Global gene expression and functional network analysis of gastric cancer identify extended pathway maps and GPRC5A as a potential biomarker

To get more understanding of the molecular mechanisms underlying gastric cancer, 25 paired samples were applied to gene expression microarray analysis. Here, expression microarray, quantitative reverse transcription-PCR (qRT-PCR) and immunohistochemical analysis indicated that GPRC5A was significantly elevated in gastric cancer tissues. The integrative network analysis of deregulated genes generated eight subnetworks. We also mapped copy number variations (CNVs) and associated mRNA expression changes into pathways and identified WNT, RTK-Ras-PI3K-AKT, NF-κB, and PLAU-JAK-STAT pathways involved in proliferation, evading apoptosis and sustained angiogenesis, respectively. Taken together, our results reveal several interesting genes including GPRC5A as potential biomarkers for gastric cancer, and highlight more systematical insight of deregulated genes in genetic pathways of gastric carcinogenesis.

Losses of chromosome 5q and 14q are associated with favorable clinical outcome of patients with gastric cancer

PURPOSE

To improve the clinical outcome of patients with gastric cancer, intensified combination strategies are currently in clinical development, including combinations of more extensive surgery, (neo)adjuvant chemotherapy, and radiotherapy. The present study used DNA copy number profiling to identify subgroups of patients with different clinical outcomes. We hypothesize that, by identification of subgroups, individual treatment strategies can be selected to improve clinical outcome and to reduce unnecessary treatment toxicity for patients with gastric cancer.

EXPERIMENTAL DESIGN

DNA from 206 gastric cancer patients was isolated and analyzed by genomewide array comparative genomic hybridization. DNA copy number profiles were correlated with lymph node status and patient survival. In addition, heat shock protein 90 (HSP90) expression was analyzed and correlated with survival in 230 gastric cancer patients.

RESULTS

Frequent (>20%) DNA copy number gains and losses were observed on several chromosomal regions. Losses on 5q11.2-q31.3 and 14q32.11-q32.33 (14% of patients) were correlated with good clinical outcome in univariate and multivariate analyses, with a median disease-free survival interval of 9.2 years. In addition, loss of expression of HSP90, located on chromosome 14q32.2, was correlated with better patient survival.

CONCLUSION

Genomewide DNA copy number profiling allowed the identification of a subgroup of gastric cancer patients, marked by losses on chromosomes 5q11.2-q31.3 and 14q32.11-q32.33 or low HSP90 protein expression, with an excellent clinical outcome after surgery alone. We hypothesize that this subgroup of patients most likely will not benefit from (neo)adjuvant systemic treatment and/or radiotherapy, whereas anti-HSP90 therapy may have clinical potential in patients with HSP90-expressing gastric cancer, pending validation in an independent dataset.

Overexpression of eIF5A-2 is an adverse prognostic marker of survival in stage I non-small cell lung cancer patients

We have previously isolated an oncogene EIF5A2 (eukaryotic initiation factor 5A2) from a frequently amplified region at 3q of a primary ovarian cancer cell line, and demonstrated its impact on prognosis in human ovarian cancer. Amplification of chromosome 3q has also been detected frequently in non-small cell lung cancer (NSCLC), however, abnormalities of EIF5A2 and its clinicopathologic significance in NSCLC haven't been studied. In our study, the methods of immunohistochemistry and fluorescence in situ hybridization were utilized to examine protein expression and amplification of EIF5A2 in 248 surgically resected NSCLCs (learning cohort) and another validation cohort of 120 stage I NSCLC patients. Overexpression and amplification of EIF5A2 was detected informatively in 48.7% and 13.7% of NSCLCs in learning cohort, 33.3% and 6.0% of NSCLCs in validation cohort. Overexpression of eIF5A-2 was found to correlate with gene amplification, increased cell proliferation and advanced T stage. In learning cohort, eIF5A-2 expression was evaluated as a strong prognostic factor on disease-specific survival, but in subgroup analyses, it only retained its stratified significance in stage I set (Hazards ratio = 2.799, p = 0.001). In validation cohort, the impact of eIF5A-2 expression on survival in stage I NSCLC patients was also observed (Hazard ratio = 2.097, p = 0.014). Our findings suggested that overexpression of eIF5A-2 correlates with local invasion of NSCLC, and might serve as an adverse prognostic marker of survival for stage I NSCLC patients.

Overexpression of eIF-5A2 in mice causes accelerated organismal aging by increasing chromosome instability

Background

Amplification of 3q26 is one of the most frequent genetic alterations in many human malignancies. Recently, we isolated a novel oncogene eIF-5A2 within the 3q26 region. Functional study has demonstrated the oncogenic role of eIF-5A2 in the initiation and progression of human cancers. In the present study, we aim to investigate the physiological and pathological effect of eIF-5A2 in an eIF-5A2 transgenic mouse model.

Methods

An eIF-5A2 transgenic mouse model was generated using human eIF-5A2 cDNA. The eIF-5A2 transgenic mice were characterized by histological and immunohistochemistry analyses. The aging phenotypes were further characterized by wound healing, bone X-ray imaging and calcification analysis. Mouse embryo fibroblasts (MEF) were isolated to further investigate molecular mechanism of eIF-5A2 in aging.

Results

Instead of resulting in spontaneous tumor formation, overexpression of eIF-5A2 accelerated the aging process in adult transgenic mice. This included decreased growth rate and body weight, shortened life span, kyphosis, osteoporosis, delay of wound healing and ossification. Investigation of the correlation between cellular senescence and aging showed that cellular senescence is not required for the aging phenotypes in eIF-5A2 mice. Interestingly, we found that activation of eIF-5A2 repressed p19 level and therefore destabilized p53 in transgenic mouse embryo fibroblast (MEF) cells. This subsequently allowed for the accumulation of chromosomal instability, such as errors in cell dividing during metaphase and anaphase. Additionally, a significantly increase in number of aneuploidy cells (p < 0.05) resulted from an increase in the incidences of misaligned and lagging chromosomal materials, anaphase bridges, and micronuclei in the transgenic mice.

Conclusion

These observations suggest that eIF-5A2 mouse models could accelerate organismal aging by increasing chromosome instability.

Molecular biomarker panels for assessment of selenium status in rats

Molecular biomarkers are mRNA transcripts that indicate the (nutrient) status of an organism or tissue. Molecular biomarker panels have the potential to readily and more accurately determine nutrient status than individual traditional biomarkers. To study the efficacy of molecular biomarker panels for predicting selenium (Se) status, we examined 30 biomarkers from rats fed graded levels of Se from deficient to eight times the minimum Se requirement, including four liver and four kidney traditional biomarkers, and 13 liver and nine kidney selenoprotein mRNA levels. Multiple regression analysis against liver and kidney Se and glutathione peroxidase-1 (Gpx1) activity, with stepwise single elimination of biomarkers that did not significantly contribute, was used to identify biomarker panels with significant (P < 0.05) regression coefficients. Resulting regression equations were then used to predict Se status, and compared with traditional Se biomarkers panels. Over the full spectrum of Se status from 0 to 0.8 microg Se/g diet, the resulting 4-selenoprotein mRNA biomarker panel predicted liver Se concentration with a correlation of 0.948, which was nominally higher and statistically the same as the correlation of 0.909 for the panel based on Gpx1 activity. The molecular biomarker panels for predicting kidney Se and liver and kidney Gpx1 activity were all comparable to predictions based on traditional biomarkers. These analyses show that molecular biomarker panels can be used to predict accurately two traditional biomarkers of Se status. The resulting analyses also illustrate that additional orthogonal biomarkers reflecting higher Se intakes are needed to better predict supernutritional Se status and further strengthen this approach.

Apoptosis induction by eIF5A1 involves activation of the intrinsic mitochondrial pathway

The regulatory role of eukaryotic translation initiation factor 5A1 (eIF5A1) in apoptosis was examined using HT-29 and HeLa S3 cells. eIF5A is the only known protein to contain the unusual amino acid, hypusine, and eIF5A1 is one of two human eIF5A family members. Two observations indicated that eIF5A1 is involved in apoptosis. First, siRNA-mediated suppression of eIF5A1 resulted in inhibition of apoptosis induced by various apoptotic stimuli, and second, adenovirus-mediated over-expression of eIF5A1 strongly induced apoptotic cell death. A mutant of eIF5A1 incapable of being hypusinated also induced apoptosis when over-expressed indicating that unhypusinated eIF5A1 is the pro-apoptotic form of the protein. Over-expression of eIF5A1 or of the mutant resulted in loss of mitochondrial transmembrane potential, translocation of Bax to the mitochondria, release of cytochrome c, caspase activation, up-regulation of p53, and up-regulation of Bim, a pro-apoptotic BH3-only Bcl-2 family protein. In addition, Bim(L) and Bim(S), the pro-apoptotic alternative spliced forms of Bim, were induced in response to over-expression of eIF5A1. Thus eIF5A1 appears to induce apoptosis by activating the mitochondrial apoptotic pathway. Proteomic analyses indicated that, of 1,899 proteins detected, 131 showed significant changes in expression (P or=1.5) within 72 h of eIF5A1 up-regulation. Among these are proteins involved in translation and protein folding, transcription factors, proteins mediating proteolysis, and a variety of proteins known to be directly involved in apoptosis. These observations collectively indicate that unhypusinated eIF5A1 plays a central role in the regulation of apoptosis.

Differential gene and protein expression in primary gastric carcinomas and their lymph node metastases as revealed by combined cDNA microarray and tissue microarray analysis

OBJECTIVE

To gain insight into the molecular events of lymph node metastasis of human gastric carcinoma.

METHODS

The gene expression profile of five matched primary gastric carcinomas and their lymph node metastases was analyzed by complementary DNA (cDNA) microarray. Differential genes were identified in the metastatic and corresponding primary tumor pairs. Among the differentially expressed genes, carbonic anhydrase II (CAII) and insulin-like growth factor binding protein 4 (IGFBP 4) genes were detected by RT-PCR. CTTN protein expression was examined by tissue microarray.

RESULTS

There was a high expression (over twofold) of 44 genes and a low expression (under twofold) of 32 genes in lymph node metastasis compared with primary gastric carcinoma, respectively. CAII mRNA was downregulated and IGFBP 4 mRNA was upregulated in paired lymph node metastases of gastric carcinomas. The overexpression of CTTN protein was related to the lymph node metastasis and the clinical stage of gastric carcinomas.

CONCLUSION

This study showed that there is a low expression of genes relative to growth signal and immune response in lymph node metastases, and a high expression of genes relative to growth factor, cell cycle, cell motility and adhesion in lymph node metastases compared with primary gastric carcinomas. The expression of CTTN was related to the invasion and metastasis of gastric cancer.

Time-series gene expression profiles in AGS cells stimulated with Helicobacter pylori

AIM: To extend the knowledge of the dynamic interaction between Helicobacter pylori (H. pylori) and host mucosa.

METHODS: A time-series cDNA microarray was performed in order to detect the temporal gene expression profiles of human gastric epithelial adenocarcinoma cells infected with H. pylori. Six time points were selected to observe the changes in the model. A differential expression profile at each time point was obtained by comparing the microarray signal value with that of 0 h. Real-time polymerase chain reaction was subsequently performed to evaluate the data quality.

RESULTS: We found a diversity of gene expression patterns at different time points and identified a group of genes whose expression levels were significantly correlated with several important immune response and tumor related pathways.

CONCLUSION: Early infection may trigger some important pathways and may impact the outcome of the infection.

Novel targets in esophageal and gastric cancer: beyond antiangiogenesis

Cancers of the stomach, gastroesophageal junction and esophagus are a major cause of cancer-related deaths worldwide. In Western countries, adenocarcinomas of the distal esophagus, gastroesophageal junction and proximal stomach have been increasing in frequency more rapidly than other malignancies. The majority of newly diagnosed patients present with advanced disease and the overall survival remains dismal at approximately 10% at 5 years. Better understanding of tumor biology has led to the development of promising novel therapeutic strategies. There is therefore increasing optimism that some of these approaches will improve the outcomes in these increasingly common cancers. Given the success of antiangiogenesis as a therapeutic strategy in various types of cancer, there are ongoing efforts to investigate the utility of other targeted therapies in the treatment of gastric and esophageal cancers. This review will focus on novel therapeutic targets other than angiogenesis and provide a rationale for the further clinical evaluation of these agents in patients with upper gastrointestinal tract cancers.

Gene expression profile towards the prediction of patient survival of gastric cancer

BACKGROUND

Several gene expression signatures have been reported to predict patient survival of gastric cancer after surgical resection. However, the prognostic gene lists have overlapped poorly until now. This study conducted an analysis to characterize gene expression profile and developed a survival prediction model.

METHODS

The gene expression profile was evaluated in fresh frozen tumor tissue obtained from 48 patients with primary gastric cancer. We measured 84 representative genes involved in transformation and tumorigenesis using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and related the results to overall survival.

RESULTS

In a univariate analysis, 84 genes were ranked on their ability to predict survival, of which nine genes were the strongest predictor (P<0.05). They were PLAU, MAP2K1, THBS1, TWIST1, ITGB5, NME4, ANGPT2, platelet-derived growth factor B (PDGFB), ITGB1. Then, we did a multivariate analysis to further select four genes (ITGB1, PDGFB, THBS1, TWIST1) from the above nine genes for the construction of biomathematics model, which was independent of age, gender, TNM stage and other variables. This model could correctly clarify gastric patients into the high-risk group, median-risk group and low-risk group, as well as predict their survival.

CONCLUSIONS

Measurement of the expression of four genes is probable to predict surgery-related survival. This model may be test further for its potential to improve the selection of the resected gastric cancer patients in adjuvant chemotherapy.

Overexpression of EIF-5A2 predicts tumor recurrence and progression in pTa/pT1 urothelial carcinoma of the bladder

The authors investigated the status of abnormalities of eIF-5A2 gene in superficial (pTa/pT1) urothelial carcinoma of the bladder (UC), as well as its correlation with clinicopathologic variables and patient outcome. The methods of immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were utilized to examine protein/mRNA(messenger RNA) expression and amplification of eIF-5A2 in a cohort of pTa/pT1 UCs. Overexpression of EIF-5A2 was examined by IHC in 38/112 (33.9%) pTa/pT1 UCs. A significant association of overexpression of EIF-5A2 with shortened UC patient recurrence-free survival (P = 0.002), as well as with shortened progression-free survival (P = 0.004), was demonstrated. Importantly, multivariate Cox regression analysis revealed that EIF-5A2 expression provided a significant independent prognostic parameter either in tumor recurrence (P = 0.002) or in tumor progression (P = 0.007). FISH results demonstrated that eIF-5A2 amplification was detected in 5/59 of the informative UCs; in each of the five cases with eIF-5A2 amplification, overexpression of EIF-5A2 was observed. In the remaining 54 UCs without eIF-5A2 amplification, 16 cases were also observed to have overexpression of EIF-5A2. In 13 pairs of UC and adjacent normal tissues, eight UCs were examined and showed up-regulated eIF-5A2 mRNA by RT-PCR, while increased expression of EIF-5A2 protein was only detected in 4/8 UCs by Western blotting. These findings suggest that overexpression of EIF-5A2, as detected by IHC, may predict tumor recurrence and progression in pTa/pT1 UC patients, and the protein expression of eIF-5A2 might be regulated not only by gene amplification, but also by other molecular mechanisms.

Overexpression of EIF-5A2 is an independent predictor of outcome in patients of urothelial carcinoma of the bladder treated with radical cystectomy

BACKGROUND

Our previous study has suggested an oncogenic role of eIF-5A2 in ovarian tumorigenesis. Abnormalities of eIF-5A2 and its clinical/prognostic significance, however, in urothelial carcinoma of the bladder (UC) are unclear.

METHODS

In this study, the methods of reverse transcription-PCR, immunohistochemistry, and fluorescence in situ hybridization were used to examine mRNA/protein expression and amplification of eIF-5A2 in a large cohort of UCs treated with radical cystectomy.

RESULTS

Up-regulated expression of eIF-5A2 mRNA was observed in 50% (8 of 16) of UCs, when compared with adjacent normal bladder tissues. Overexpression of EIF-5A2 protein and amplification of eIF-5A2 was examined informatively in 45.3% (39 of 86) and 10.6% (5 of 47) of UCs, respectively. In univariate survival analysis of the UC cohorts, a significant association of overexpression of EIF-5A2 with shortened patient survival (mean, 38.2 months versus 52.9 months, P = 0.001, log-rank test) was shown. In different subsets of UC patients, overexpression of EIF-5A2 was also a prognostic indicator in grade 1/2 (P = 0.0009) and grade 3 (P = 0.016) tumor patients, and in pT1 (P = 0.0089), pT2 (P = 0.0354), pT3/4 (P = 0.0058), pN0 (P = 0.0039), and pN1-2 (P = 0.0093) tumor patients. Importantly, EIF-5A2 expression (P = 0.0007) together with pT stage (P = 0.0001) provided significant independent prognostic variables in multivariate analysis.

CONCLUSIONS

These findings indicate that overexpression of EIF-5A2 in UCs is coincident with acquisition of a poor prognostic phenotype, suggesting that the expression of EIF-5A2, as detected by immunohistochemistry, is an independent molecular marker for shortened survival time of UC patients treated with radical cystectomy.

Expression and amplification of eIF-5A2 in human epithelial ovarian tumors and overexpression of EIF-5A2 is a new independent predictor of outcome in patients with ovarian carcinoma

OBJECTIVES

Our previous study has suggested an oncogenic role of eIF-5A2 in ovarian tumorigenesis. Abnormalities of eIF-5A2 and its clinical/prognostic significance, however, in ovarian carcinoma are unclear.

METHODS

In this study, we examined expression of EIF-5A2, using immunohistochemistry, in 30 normal ovaries, 30 ovarian cystadenomas, 30 borderline ovarian tumors and 110 ovarian carcinomas. The amplification status of eIF-5A2 in each ovarian carcinoma was assessed by fluorescence in situ hybridization.

RESULTS

Overexpression of EIF-5A2 was detected in none of the normal ovaries, 7% cystadenomas, 30% borderline tumors, and 53% invasive ovarian carcinomas, respectively. Amplification of eIF-5A2 was detected in 16% of informative ovarian carcinomas. In ovarian carcinomas, significant positive associations were found between overexpression of EIF-5A2 and the tumors ascending grade, later pT/pN and FIGO stages, as well as increased positive rate of Ki-67 (p<0.05). In univariate survival analysis of the ovarian carcinoma cohorts, a significant association of overexpression of EIF-5A2 with shortened patient survival (mean 39.0 months vs 69.5 months, p<0.001) was demonstrated. Importantly, EIF-5A2 expression provided significant independent prognostic parameters in multivariate analysis (p=0.043).

CONCLUSIONS

These findings suggest that increased expression of EIF-5A2 in ovarian carcinoma may represent an acquired malignant phenotypic feature of tumor cells, and the overexpression of EIF-5A2, as detected by immunohistochemistry, is an independent molecular marker for shortened survival time of patients with ovarian carcinoma.