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

Prognostic value of EIF5A2 in solid tumors: A meta-analysis and bioinformatics analysis

Aims

In cancer biology, the aberrant overexpression of eukaryotic translation initiation factor 5A2 (EIF5A2) has been correlative with an ominous prognosis, thereby underscoring its pivotal role in fostering metastatic progression. Consequently, EIF5A2 has garnered significant attention as a compelling prognostic biomarker for various malignancies. Our research endeavors were thus aimed at elucidating the utility and significance of EIF5A2 as a robust indicator of cancer outcome prediction.

Method

An exhaustive search of the PubMed, EMBASE, and Web of Science databases found relevant studies. The link between EIF5A2 and survival prognosis was examined using hazard ratios and 95% confidence intervals. Subsequently, The Cancer Genome Atlas (TCGA) and the Gene Expression Profiling Interactive Analysis (GEPIA) databases were employed to validate EIF5A2 expression across various cancer types.

Results

Through pooled analysis, we found that increased EIF5A2 expression was significantly associated with decreased overall survival (OS) and disease-free survival/progression-free survival/relapse-free survival (DFS/PFS/RFS). Moreover, TCGA analysis revealed that EIF5A2 was significantly upregulated in 27 types of cancer, with overexpression being linked to shorter OS in three, worse DFS in two, and worse PFS in six types of cancer. GEPIA showed that patients with EIF5A2 overexpression had reduced OS and DFS.

Conclusions

In solid tumors, EIF5A2 emerges as a reliable prognostic marker. Our meta-analysis comprehensively analyzed the prognostic value of EIF5A2 in solid tumors and assessed its efficacy as a predictive marker.

Targeting eIF5A2 reduces invasion and reverses chemoresistance in SCC-9 cells in vitro

BACKGROUND AND AIMS

Eukaryotic translation initiation factor 5A2 (EIF5A2) has been reported to be involved in metastasis and chemotherapy resistance in many human cancers. However, the effect and mechanism of EIF5A2 in oral cancer cells are unknown. Here, we investigated the effects of targeting EIF5A2 on chemotherapy resistance in oral cancer cells in vitro.

METHODS

By using a lentiviral system, we investigated the effects of targeting EIF5A2 on the invasion, migration, growth, and chemosensitivity of SCC-9 cells to CDDP in vitro. Through the method of gene intervention, we explore the role of pro-apoptotic Bim and epithelial and mesenchymal marker E-cadherin protein in this process and the regulation of EIF5A2 on Bim and E-cadherin.

RESULTS

Targeting EIF5A2 reduces invasion and migration in SCC-9 cells partly through upregulation of E-cadherin expression; Targeting EIF5A2 promotes cell apoptosis and inhibits cell survival as well as increasing chemosensitivity in SCC-9 cells through upregulation of Bim expression.

CONCLUSION

EIF5A2 may be a novel potential therapeutic target for oral cancer by upregulation of Bim and E-cadherin.

Hypusination-induced DHPS/eIF5A pathway as a new therapeutic strategy for human diseases: A mechanistic review and structural classification of DHPS inhibitors

The discovery of new therapeutic strategies for diseases is essential for drug research. Deoxyhypusine synthase (DHPS) is a critical enzyme that modifies the conversion of the eukaryotic translation initiation factor 5A (eIF5A) precursor into physiologically active eIF5A (eIF5A-Hyp). Recent studies have revealed that the hypusine modifying of DHPS on eIF5A has an essential regulatory role in human diseases. The hypusination-induced DHPS/eIF5A pathway has been shown to play an essential role in various cancers, and it could regulate immune-related diseases, glucose metabolism-related diseases, neurological-related diseases, and aging. In addition, DHPS has a more defined substrate and a well-defined structure within the active pocket than eIF5A. More and more researchers are focusing on the prospect of advanced development of DHPS inhibitors. This review summarizes the regulatory mechanisms of the hypusination-induced DHPS/eIF5A pathway in a variety of diseases in addition to the inhibitors related to this pathway; it highlights and analyzes the structural features and mechanisms of action of DHPS inhibitors and expands the prospects of future drug development using DHPS as an anticancer target.

Eukaryotic Initiation Factor 5A2 localizes to actively translating ribosomes to promote cancer cell protrusions and invasive capacity

BACKGROUND

Eukaryotic Initiation Factor 5A (eIF-5A), an essential translation factor, is post-translationally activated by the polyamine spermidine. Two human genes encode eIF-5A, being eIF5-A1 constitutively expressed whereas eIF5-A2 is frequently found overexpressed in human tumours. The contribution of both isoforms with regard to cellular proliferation and invasion in non-small cell lung cancer remains to be characterized.

METHODS

We have evaluated the use of eIF-5A2 gene as prognosis marker in lung adenocarcinoma (LUAD) patients and validated in immunocompromised mice. We have used cell migration and cell proliferation assays in LUAD lines after silencing each eIF-5A isoform to monitor their contribution to both phenotypes. Cytoskeleton alterations were analysed in the same cells by rhodamine-phalloidin staining and fluorescence microscopy. Polysome profiles were used to monitor the effect of eIF-5A2 overexpression on translation. Western blotting was used to study the levels of eIF-5A2 client proteins involved in migration upon TGFB1 stimulation. Finally, we have co-localized eIF-5A2 with puromycin to visualize the subcellular pattern of actively translating ribosomes.

RESULTS

We describe the differential functions of both eIF-5A isoforms, to show that eIF5-A2 properties on cell proliferation and migration are coincident with its features as a poor prognosis marker. Silencing of eIF-5A2 leads to more dramatic consequences of cellular proliferation and migration compared to eIF-5A1. Overexpression of eIF-5A2 leads to enhanced global translation. We also show that TGFβ signalling enhances the expression and activity of eIF-5A2 which promotes the translation of polyproline rich proteins involved in cytoskeleton and motility features as it is the case of Fibronectin, SNAI1, Ezrin and FHOD1. With the use of puromycin labelling we have co-localized active ribosomes with eIF-5A2 not only in cytosol but also in areas of cellular protrusion. We have shown the bulk invasive capacity of cells overexpressing eIF-5A2 in mice.

CONCLUSIONS

We propose the existence of a coordinated temporal and positional interaction between TFGB and eIF-5A2 pathways to promote cell migration in NSCLC. We suggest that the co-localization of actively translating ribosomes with hypusinated eIF-5A2 facilitates the translation of key proteins not only in the cytosol but also in areas of cellular protrusion. Video Abstract.

The pleiotropic roles of eIF5A in cellular life and its therapeutic potential in cancer

Protein synthesis is dysregulated in the majority of cancers and this process therefore provides a good therapeutic target. Many novel anti-cancer agents are directed to target the initiation stage of translation, however, translation elongation also holds great potential as a therapeutic target. The elongation factor eIF5A that assists the formation of peptidyl bonds during the elongation process is of considerable interest in this regard. Overexpression of eIF5A has been linked with the development of a variety of cancers and inhibitors of the molecule have been proposed for anti-cancer clinical applications. eIF5A is the only protein in the cell that contains the post-translational modification hypusine. Hypusination is a two-step enzymatic process catalysed by the Deoxyhypusine Synthase (DHPS) and Deoxyhypusine Hydroxylase (DOHH). In addition, eIF5A can be acetylated by p300/CBP-associated factor (PCAF) which leads to translocation of the protein to the nucleus and its deactivation. In addition to the nucleus, eIF5A has been found in the mitochondria and the endoplasmic reticulum (ER) with eIF5A localisation related to function from regulation of mitochondrial activity and apoptosis to maintenance of ER integrity and control of the unfolded protein response (UPR). Given the pleiotropic functions of eIF5A and by extension the hypusination enzymes, this system is being considered as a target for a range of cancers including multiple myeloma, B-Cell lymphoma, and neuroblastoma. In this review, we explore the role of eIF5A and discuss the therapeutic strategies that are currently developing both in the pre- and the clinical stage.

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.

LncRNA FOXP4-AS promotes the progression of non-small cell lung cancer by regulating the miR-3184-5p/EIF5A axis

Long non coding RNA FOXP4-AS1 exerted crucial functions in various human cancers, while its role in non-small cell lung cancer (NSCLC) remains unclear. A total of 30 pairs of NSCLC tissues and matched adjacent normal tissues were used to evaluate the expression of FOXP4-AS1 and miR-3184-5p. Cell proliferation was assessed by CCK-8 assay and colony formation assay. Cell apoptosis was measured by flow cytometry. Bioinformatic analysis and luciferase reporter assay were performed to determine the regulatory relationship among FOXP4-AS1, miR-3184-5p and EIF5A. The xenograft tumor model was constructed to confirm the function of FOXP4-AS1 in NSCLC progression. The results showed that FOXP4-AS1 was upregulated and miR-3184-5p was downregulated in NSCLC tissues and cell lines. Downregulation of FOXP4-AS1 significantly reduced cell proliferation and induced apoptosis of NSCLC cells in vitro. FOXP4-AS1 could regulated the expression of EIF5A by binding to miR-3184-5p. Rescue experiments showed that downregulation of miR-3184-5p or overexpression of EIF5A obviously attenuated the inhibitory effects of si-FOXP4-AS1 on cell proliferation, as well as the stimulating effects on cell apoptosis. Moreover, knockdown of FOXP4-AS1 could efficiently inhibited tumor development of NSCLC in vivo. Downregulation of FOXP4-AS1 attenuated the progression of NSCLC by regulating miR-3184-5p and EIF5A.

EIF5A expression and its role as a potential diagnostic biomarker in hepatocellular carcinoma

Introduction and objectives: Eukaryotic translation initiation factor 5A (EIF5A) is a member of the identified eIF family and played an important role in cell proliferation. There are few studies about the correlation between EIF5A and hepatocellular carcinoma (HCC).

Materials and methods: We evaluated the expression of the EIF5A in human HCC cell lines and tissues by western blot analysis. Immunohistochemistry analysis of EIF5A was performed on a tissue microarray including 10 normal liver samples and 90 pathological section of HCC. Receiver operating characteristic (ROC) was introduced to obtain an optimal cut-off score for EIF5A positive expression.

Results: Western blot results showed that EIF5A was highly expressed in HCC cell lines and tissues. Based on ROC curve analysis, 1/10 (10.0%) of normal hepatic tissues and 67/90 (74.4%) of HCC tissues were tested positive for EIF5A expression, which indicated that EIF5A were significantly up-regulated in HCC tissues compared with normal liver tissues (χ²=17.177, P<0.001). Furthermore, expression of EIF5A was significantly correlated with histological grade (P=0.048), clinical stage (P=0.003) and pT stage (P=0.003) but not correlated with sex (P=0.617) and age (P=0.831).

Conclusions: In our study, we demonstrated the expression of EIF5A is closely correlated with HCC. In consideration of its relationship with clinicopathological parameters including histological grade, clinical stage and pT stage of HCC, EIF5A could be a potential biomarker.

Multifaceted control of mRNA translation machinery in cancer

The mRNA translation machinery is tightly regulated through several, at times overlapping, mechanisms that modulate its efficiency and accuracy. Due to their fast rate of growth and metabolism, cancer cells require an excessive amount of mRNA translation and protein synthesis. However, unfavorable conditions, such as hypoxia, amino acid starvation, and oxidative stress, which are abundant in cancer, as well as many anti-cancer treatments inhibit mRNA translation. Cancer cells adapt to the various internal and environmental stresses by employing specialised transcript-specific translation to survive and gain a proliferative advantage. We will highlight the major signaling pathways and mechanisms of translation that regulate the global or mRNA-specific translation in response to the intra- or extra-cellular signals and stresses that are key components in the process of tumourigenesis.

Expression and Prognostic Significance of Metastasis-Associated Protein 1 in Gastrointestinal Cancer

Background

Metastasis-associated protein 1 (MTA1) has been considered as a transcriptional regulator, which is significantly related to the prognosis in various types of tumors. However, whether MTA1 is a potential prognostic index of gastrointestinal cancer (GIC) remains controversial. The current meta-analysis was performed to evaluate the role of MTA1 expression in the prediction of the clinicopathological features and survival in GIC cases. And the results of gastric cancer were verified by immunohistochemistry (IHC).

Methods

Eligible studies assessing the relationship between MTA1 and GIC by IHC were searched in the PubMed, Cochrane, Ovid, Web of Science and CNKI databases by various search strategies. The STATA 16.0 software was applied to gather data and to analyze the potential relationship between MTA1 and GIC. The expression level of MTA1 was examined in 80 GC samples by IHC assay. SPSS 20.0 was applied for statistical analysis, and the survival curves were calculated by the Kaplan-Meier method. The data of 95% CI was displayed as “[a-b]”.

Results

According to the meta-analysis, the expression level of MTA1 was tightly associated with the tumor size (OR=1.82 [1.16–2.84], P=0.009), tumor tissue differentiation (OR=1.71 [1.24–2.37], P=0.001), depth of invasion (OR=3.12 [2.55–3.83], P<0.001), lymphatic metastasis (OR=2.99 [2.02–4.43], P<0.001), distant metastasis (OR=4.66 [1.13–19.24], P=0.034), TNM stage (OR=4.28 [2.76–6.63], P<0.001). In addition, MTA1 played the negative effects in 1- (RR=2.48 [1.45–4.25], P=0.001), 3- (RR=1.66 [1.30–2.11], P<0.001) and 5-year (RR=1.73 [1.37–2.20], P<0.001). Study in subgroup, grouped by language and tumor type, we reached similar conclusions. Further validation by IHC yielded similar conclusions. Tumor size (P=0.008), lymph node metastasis (P=0.007) and distant metastasis (P=0.023) significantly accompanied with higher expression of MAT1 in GC cases. Besides, the expression level of MTA1 was statistically significantly correlated with OS in GC cases (HR=2.061 [1.066–3.986], P=0.032), which suggested that MTA1 might be an independent prognostic marker for GC. Finally, we verified the correlation between the expression level of MTA1 and prognosis of GC in 80 GC samples.

Conclusions

MTA1 is tightly associated with metastasis-related factors and may constitute a promising prognostic factor of GIC.

Knockdown of eukaryotic translation initiation factor 5A2 enhances the therapeutic efficiency of doxorubicin in hepatocellular carcinoma cells by triggering lethal autophagy

Hepatocellular carcinoma (HCC) is an invasive malignant neoplasm with a poor prognosis. The development of chemoresistance severely obstructs the chemotherapeutic efficiency of HCC treatment. Therefore, understanding the mechanisms of chemoresistance is important for improving the outcomes of patients with HCC. Eukaryotic translation initiation factor 5A2 (eIF5A2), which is considered to be an oncogene, has been reported to mediate chemoresistance in various types of cancer; however, its precise role in HCC remains unclear. Accumulating evidence has suggested that autophagy serves a dual role in cancer chemotherapy. The present study aimed to investigate the role of autophagy in eIF5A2‑mediated doxorubicin resistance in HCC. High expression levels of eIF5A2 in human HCC tissues were observed by immunohistochemistry using a tissue microarray, which was consistent with the results of reverse transcription‑quantitative PCR analysis in paired HCC and adjacent healthy tissues. HCC patient‑derived tumor xenograft mouse model was used for the in vivo study, and knockdown of eIF5A2 effectively enhanced the efficacy of doxorubicin chemotherapy compared with that in the control group. Notably, eIF5A2 served as a repressor in regulating autophagy under chemotherapy. Silencing of eIF5A2 induced doxorubicin sensitivity in HCC cells by triggering lethal autophagy. In addition, 5‑ethynyl‑2'‑deoxyuridine, lactate dehydrogenase release assay and calcein‑AM/PI staining were used to determine the enhanced autophagic cell death induced by the silencing of eIF5A2 under doxorubicin treatment. Suppression of autophagy attenuated the sensitivity of HCC cells to doxorubicin induced by eIF5A2 silencing. The results also demonstrated that knockdown of the Beclin 1 gene, which is an autophagy regulator, reversed the enhanced autophagic cell death and doxorubicin sensitivity induced by eIF5A2 silencing. Taken together, these results suggested eIF5A2 may mediate the chemoresistance of HCC cells by suppressing autophagic cell death under chemotherapy through a Beclin 1‑dependent pathway, and that eIF5A2 may be a novel potential therapeutic target for HCC treatment.

Eukaryotic translation initiation factor 5A in the pathogenesis of cancers

Cancer is the leading cause of death worldwide. The absence of obvious symptoms and insufficiently sensitive biomarkers in early stages of carcinoma limits early diagnosis. Cancer therapy agents and targeted therapy have been used extensively against tissues or organs of specific cancers. However, the intrinsic and/or acquired resistance to the agents or targeted drugs as well as the serious toxic side effects of the drugs would limit their use. Therefore, identifying biomarkers involved in tumorigenesis and progression represents a challenge for cancer diagnosis and therapeutic strategy development. The eukaryotic translation factor 5A (eIF5A), originally identified as an initiation factor, was later shown to promote translation elongation of iterated proline sequences. There are two eIF5A isoforms (eIF5A1 and eIF5A2). eIF5A2 protein consists of 153 residues, and shares 84% amino acid identity with eIF5A1. However, the biological functions of these two isoforms may be significantly different. Recently, it was demonstrated that eIF5Ais widely involved in the pathogenesis of a number of diseases, including cancers. In particular, eIF5A plays an important role in regulating tumor growth, invasion, metastasis and tumor microenvironment. It was also shown to serve as a potential biomarker and target for the diagnosis and treatment of cancers. The present review briefly discusses the latest findings of eIF5A in the pathogenesis of certain malignant cancers and evolving clinical applications.

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.

Long non-coding RNA LINC00520 promotes the proliferation and metastasis of malignant melanoma by inducing the miR-125b-5p/EIF5A2 axis

BACKGROUND

Long intergenic non-protein coding RNA 520 (LINC00520), a novel identified lncRNA, has been shown to modulate the malignant phenotype of tumor cells in some malignant tumors. However, the exact role and molecular mechanism of LINC00520 in malignant melanoma has not been studied.

METHODS

The expression of LINC00520 in melanoma tissues were detected by using RNA-seq analysis and qRT-PCR. Melanoma cases from the public databases (The Cancer Genome Atlas (TCGA), GEO#GSE15605, GEO#GSE34460 and GEO#GSE24996) were included in this study. CCK-8 assay, EdU assay, transwell and scratch wound assay were used to explore the role of LINC00520 in melanoma cells. Luciferase reporter assays, MS2-RIP, RNA pull-down and RNA-ChIP assay were used to demonstrate the molecular biological mechanism of LINC00520 in melanoma.

RESULTS

We found that LICN00520 was found to be overexpressed in melanoma tissue. High expression of LICN00520 is a risk factor for the prognosis of melanoma patients. LINC00520 promotes the proliferation, invasion and migration of melanoma cells. LICN00520 exerted its oncogenic role by competitive binding miR-125b-5p to promote Eukaryotic initiation factor 5A2 (EIF5A2) expression. We also showed that LICN00520 promotes the growth and metastasis of melanoma in vivo through regulating miR-125b-5p/EIF5A2 axis.

CONCLUSIONS

All results elucidated the role and molecular mechanism of LINC00520 in the malignant development of melanoma. LINC00520, a new oncogene in melanoma, maybe serve as a survival biomarkers or therapeutic target for melanoma patients.

Long non-coding RNA GAS6-AS1 acts as a ceRNA for microRNA-585, thereby increasing EIF5A2 expression and facilitating hepatocellular carcinoma oncogenicity

Long non-coding RNA termed GAS6 antisense RNA 1 (GAS6-AS1) plays an essential role in gastric and non-small cell lung cancers. Nonetheless, the function of GAS6-AS1 in hepatocellular carcinoma (HCC) has not been so far studied in detail. In this study, reverse-transcription quantitative PCR was performed to measure GAS6-AS1 expression in HCC samples. A series of functional experiments, including MTT assay, colony formation assay, flow-cytometric analysis, and transwell migration and invasion assays, was performed to determine the influence of GAS6-AS1 knockdown on the malignant phenotype of HCC. The results showed that GAS6-AS1 was significantly upregulated in HCC tissue samples and cell lines. Increased GAS6-AS1 expression was associated with tumor size, Edmondson grade, and Tumor-Node-Metastasis (TNM) stage among patients with HCC. The overall survival of patients with HCC characterized with high expression of GAS6-AS1 was significantly shorter in comparison to that of patients with low level of GAS6-AS1. Functional experiments indicated that knockdown of GAS6-AS1 suppressed HCC cell proliferation, colony formation, migration, and invasion in vitro; promoted apoptosis in vitro; and decreased tumor growth in vivo. Of note, GAS6-AS1 was validated as a competing endogenous RNA (ceRNA) for microRNA-585 (miR-585) and consequently increased the expression of eukaryotic translation initiation factor 5A2 (EIF5A2). Finally, rescue experiments confirmed the association among GAS6-AS1, miR-585, and EIF5A2 in HCC cells. Our study provides substantial evidence that the GAS6-AS1/miR-585/EIF5A2 pathway plays an important role in HCC progression and that might be considered as a potential target for therapeutic approaches in HCC.

Half Way to Hypusine-Structural Basis for Substrate Recognition by Human Deoxyhypusine Synthase

Deoxyhypusine synthase (DHS) is a transferase enabling the formation of deoxyhypusine, which is the first, rate-limiting step of a unique post-translational modification: hypusination. DHS catalyses the transfer of a 4-aminobutyl moiety of polyamine spermidine to a specific lysine of eukaryotic translation factor 5A (eIF5A) precursor in a nicotinamide adenine dinucleotide (NAD)-dependent manner. This modification occurs exclusively on one protein, eIF5A, and it is essential for cell proliferation. Malfunctions of the hypusination pathway, including those caused by mutations within the DHS encoding gene, are associated with conditions such as cancer or neurodegeneration. Here, we present a series of high-resolution crystal structures of human DHS. Structures were determined as the apoprotein, as well as ligand-bound states at high-resolutions ranging from 1.41 to 1.69 Å. By solving DHS in complex with its natural substrate spermidine (SPD), we identified the mode of substrate recognition. We also observed that other polyamines, namely spermine (SPM) and putrescine, bind DHS in a similar manner as SPD. Moreover, we performed activity assays showing that SPM could to some extent serve as an alternative DHS substrate. In contrast to previous studies, we demonstrate that no conformational changes occur in the DHS structure upon spermidine-binding. By combining mutagenesis and a light-scattering approach, we show that a conserved “ball-and-chain” motif is indispensable to assembling a functional DHS tetramer. Our study substantially advances our knowledge of the substrate recognition mechanism by DHS and may aid the design of pharmacological compounds for potential applications in cancer therapy.

Overexpression of microRNA-9 enhances cisplatin sensitivity in hepatocellular carcinoma by regulating EIF5A2-mediated epithelial-mesenchymal transition

We investigated the role of microRNA (miR)-9 in modulating chemoresistance in hepatocellular carcinoma (HCC) cells. MiR-9 was overexpressed or knocked down in HCC cell lines. Cell viability, cell proliferation, the expression of EIF5A2 and the epithelial-mesenchymal transition (EMT)-related proteins were examined. HCC cells overexpressing miR-9 were more sensitive to cisplatin; miR-9 knockdown yielded the opposite result. The in vivo nude mouse HCC xenograft tumors yielded the same results. EIF5A2 was identified as a potential target of miR-9, where miR-9 regulated EIF5A2 expression at mRNA and protein level. EIF5A2 knockdown reversed miR-9 inhibition-mediated cisplatin resistance. Altering miR-9 and EIF5A2 expression changed E-cadherin and vimentin expression. Furthermore, EIF5A2 mediated miR-9 EMT pathway regulation, indicating that miR-9 can enhance cisplatin sensitivity by targeting EIF5A2 and inhibiting the EMT pathway. Targeting miR-9 may be useful for overcoming drug resistance in HCC.

Recent insights into eukaryotic translation initiation factors 5A1 and 5A2 and their roles in human health and disease

The eukaryotic translation initiation factor 5A1 (eIF5A1) and its homolog eIF5A2 are the only two human proteins containing the unique post-translational modification-hypusination, which is essential for the function of these two proteins. eIF5A1 was initially identified as a translation initiation factor by promoting the first peptide bond formation of protein during translation; however, recent results suggest that eIF5A1 also functions as a translation elongation factor. It has been shown that eIF5A1 is implicated in certain human diseases, including diabetes, several human cancer types, viral infections and diseases of neural system. Meanwhile, eIF5A2 is overexpressed in many cancers, and plays an important role in the development and progression of cancers. As multiple roles of these two factors were observed among these studies, therefore, it remains unclear whether they act as oncogene or tumor suppressor. In this review, the recent literature of eIF5As and their roles in human diseases, especially in human cancers, will be discussed.

Long Noncoding RNA TP73-AS1 Modulates Medulloblastoma Progression In Vitro And In Vivo By Sponging miR-494-3p And Targeting EIF5A2

Background

Previous studies have shown that P73 antisense RNA 1T (non-protein coding), also known as TP73-AS1, is a long non-coding RNA (lncRNA) and involved in the development of medulloblastoma. However, the regulatory mechanism of lncRNA TP73-AS1 in medulloblastoma was still unclear, the present study was aimed to investigate the detailed functions and the mechanism of TP73-AS1 in regulation of medulloblastoma.

Materials and methods

The levels of TP73-AS1, miR-494-3p, and Eukaryotic initiation factor 5A2 (EIF5A2) were determined using quantitative real-time PCR (qRT-PCR), in situ hybridization (ISH), or Immunohistochemistry (IHC). The function of TP73-AS1 in proliferation, apoptosis, migration, and invasion of medulloblastoma cells was evaluated using cell counting Kit-8 (CCK-8), flow cytometry, and transwell assay, respectively. The protein levels were determined by Western blot. Bioinformatics analysis and dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assay were used to search and confirm the target gene of TP73-AS1 and miR-494-3p. The effect of TP73-AS1 knockdown in vivo was detected by animal experiment.

Results

The levels of TP73-AS1 and EIF5A2 were up-regulated, while miR-494-3p expression was down-regulated in medulloblastoma tissues and cells, ELF5A2 was a direct target of miR-494-3p, and miR-494-3p bound to TP73-AS1. The knockdown of TP73-AS1 inhibited cell proliferation, invasion, migration, and promoted apoptosis of medulloblastoma cells, while the miR-494-3p inhibitor abolished the effects of TP73-AS1 knockdown on medulloblastoma cells.

Conclusion

TP73-AS1 positively regulated EIF5A2 expression by sponging miR-494-3p. These findings suggested that TP73-AS1 served as an oncogene and promoted the progression of medulloblastoma.

MicroRNA-383 inhibits doxorubicin resistance in hepatocellular carcinoma by targeting eukaryotic translation initiation factor 5A2

Drug resistance occurs commonly in cancers, especially in hepatocellular carcinoma (HCC). Accumulating evidence has demonstrated that microRNAs (miRNAs) play a vital role in tumour chemoresistance. However, little is known about the role of miR-383 in HCC chemoresistance. In the present study, RT-PCR and western blotting were used to identify the expression profile of miR-383 and eukaryotic translation initiation factor 5A2 (EIF5A2). The bioinformatics website Targetscan was used to predict the target genes of miR-383. In vitro and in vivo loss- and gain-of-function studies were performed to reveal the effects and potential mechanism of the miR-383/EIF5A2 axis in chemoresistance of HCC cells. The expression level of miR-383 correlated negatively with doxorubicin (Dox) sensitivity. Overexpression of miR-383 promoted HCC cells to undergo Dox-induced cytotoxicity and apoptosis, whereas miR-383 knockdown had the opposite effects. EIF5A2 was predicted as a target gene of miR-383. EIF5A2 knockdown sensitized HCC cells to Dox. Moreover, miR-383 inhibition-mediated HCC Dox resistance could be reversed by silencing EIF5A2. Finally, we demonstrated that miR-383 inhibition could enhance Dox sensitivity by targeting EIF5A2 in vivo. The results indicated that miR-383 inhibited Dox resistance in HCC cells by targeting EIF5A2. Targeting the miR-383/EIF5A2 axis might help to alleviate the chemoresistance of HCC cells.

MicroRNA-33a-5p overexpression sensitizes triple-negative breast cancer to doxorubicin by inhibiting eIF5A2 and epithelial-mesenchymal transition

Drug resistance is a significant obstacle when treating triple-negative breast cancer (TNBC). Several studies have demonstrated that microRNAs (miRNAs) have essential roles in regulating drug resistance in different types of cancer. miR-33a-5p has previously been reported to be a tumor suppressor in several types of cancer. However, its role in breast cancer remains unknown. The present study aimed to investigate the role of miR-33a-5p in the chemoresistance of TNBC and uncover its potential molecular mechanisms. Cell Counting Kit-8 assay was used to examine cell proliferation, reverse transcription-quantitative PCR analysis was used to examine miR-33a levels, and western blotting and immunofluorescence assays were used to examine the expression of epithelial-mesenchymal transition (EMT)-associated proteins and of eukaryotic translation initiation factor 5A2 (eIF5A2). The results indicated that miR-33a-5p expression was lower in TNBC cells compared with non-TNBC cells. miR-33a-5p overexpression significantly improved the doxorubicin (Dox) sensitivity of TNBC cells, but not that of non-TNBC cells. It was then observed that Dox treatment inhibited miR-33a-5p expression and induced EMT in TNBC cells, by increasing the expression levels of vimentin, while decreasing the expression levels of E-cadherin. Furthermore, it was revealed that forced expression of miR-33a-5p attenuated Dox-induced EMT. eIF5A2 was identified as a potential target of miR-33a-5p, and miR-33a-5p overexpression inhibited the expression of eIF5A2. eIF5A2 inhibition, via its inhibitor GC7, sensitized TNBC cells to Dox and reversed Dox-induced EMT. Overall, the present study demonstrated that miR-33a-5p enhanced the sensitivity of TNBC cells to Dox, by suppressing eIF5A2 expression and reversing Dox-induced EMT, providing a potential therapeutic target for treating drug-resistant TNBC.

Thermo-chemotherapy inhibits the proliferation and metastasis of gastric cancer cells via suppression of EIF5A2 expression

Purpose

Thermo-chemotherapy (TCT) is a new approach for the treatment of cancer that combines chemotherapy with thermotherapy. In the present study, we investigated the relationship between eukaryotic translation initiation factor 5A2 (EIF5A2) and TCT sensitivity in gastric cancer (GC) to further illuminate the molecular mechanism underlying the effect of TCT on GC.

Methods

A TCT cell model was constructed, and EIF5A2 was silenced or overexpressed by infection with a lentivirus expressing either EIF5A2 or EIF5A2 shRNA. Then, RT-qPCR, Western blotting, and immunohistochemistry assays were performed to evaluate the changes in the expression levels of EIF5A2, c-myc, vimentin, and E-cadherin. Cell proliferation and xenograft assays were conducted to evaluate the effect on cell proliferation. Finally, wound-healing and Transwell invasion assays were performed to evaluate the effects on migration and invasion.

Results

TCT reduced EIF5A2 expression at both the mRNA and protein levels. It also inhibited cell proliferation, migration, and invasion, downregulated the expression of c-myc and vimentin, and increased the expression of E-cadherin in both MKN28 and MKN45 cells. Silencing of EIF5A2 enhanced the above effects of TCT on MKN28 and MKN45 cells, while overexpression of EIF5A2 had the opposite effects. In addition, EIF5A2 overexpression weakened the inhibitory effect of TCT on tumor growth in vivo as well as the effects on c-myc, vimentin, and E-cadherin.

Conclusion

TCT inhibits GC cell proliferation and metastasis by suppressing EIF5A2 expression. Our results provide new insights into our understanding of the molecular mechanism underlying the effects of TCT in GC.

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.

Overexpression of EIF5A2 in upper urinary tract urothelial carcinoma is a new independent prognostic marker of survival

Aim: To study the expression of EIF5A2 in urinary tract urothelial carcinoma and its clinicopathological features and prognosis. Methods: EIF5A2 expression was detected via immunohistochemistry in 101 patients. Results: Kaplan-Meier analysis showed that the EIF5A2 low expression group had significantly longer overall survival (OS; p < 0.001) and progression-free survival (PFS; p < 0.001) than the EIF5A2 high expression group. The high expression of EIF5A2 significantly predict poor OS and PFS in the subset patients (p < 0.05). EIF5A2 was an independent prognostic factor for OS and PFS (p = 0.003 and p = 0.001). The established nomogram model and its calibration curve predicted the probability of survival accurately. Conclusion: EIF5A2 is a potential molecular marker of poor prognosis in urinary tract urothelial carcinoma.

Eukaryotic translation initiation factor 5A2 is highly expressed in prostate cancer and predicts poor prognosis

Eukaryotic translation initiation factor (EIF) 5A2 exerts important functions that regulate the development and progression of cancers. The present study aimed to investigate the expression of EIF5A2 in prostate cancer (PCa) and its association with biological and prognostic significance. EIF5A2 mRNA and protein levels were analyzed in three paired samples of freshly resected PCa and adjacent non-tumor tissues. Immunohistochemical staining was used to detect the expression of EIF5A2 protein levels in 72 paraffin-embedded PCa tumor specimens. Subsequently, the association between EIF5A2 protein expression and clinicopathological parameters was assessed. Semi-quantitative reverse transcription-polymerase chain reaction and western blot analyses showed both EIF5A2 mRNA and protein levels were elevated in PCa compared with adjacent non-tumor tissues. Elevated EIF5A2 protein levels were observed in 73.6% (53/72) of the clinical PCa tissues using immunohistochemical staining. EIF5A2 expression was significantly associated with tumor stage (P=0.011) and biochemical recurrence status (P=0.032). Additionally, high levels of EIF5A2 predicted worse progression-free survival (P=0.007). Multivariate Cox regression analysis indicated that high expression of EIF5A2 was an independent prognostic factor for poor progression-free survival (hazard ratios, 0.366; 95% confidence interval, 0.349-0.460; P=0.021). The present study demonstrated that EIF5A2 is overexpressed in prostate cancer and may be a potential predictor and therapeutic target in PCa patients.

Downregulation of EIF5A2 by miR-221-3p inhibits cell proliferation, promotes cell cycle arrest and apoptosis in medulloblastoma cells

Recently, miR-221-3p expression has been reported to be down-regulated in medulloblastoma (MB), but its functional effects remains unclear. In this study, quantitative real-time PCR (qRT-PCR) revealed significantly decreased miR-221-3p in MB cell lines. Transfection of miR-221-3p mimics reduced, or inhibitor increased cell proliferation in MB cells using MTT assay. Flow cytometry analysis indicated miR-221-3p overexpression promoted, while knockdown alleviated G0/G1 arrest and apoptosis. Luciferase reporter assay confirmed miR-221-3p directly targets the EIF5A2 gene. Moreover, restoration of EIF5A2 in the miR-221-3p-overexpressing DAOY cells significantly alleviated the suppressive effects of miR-221-3p on cell proliferation, cell cycle and apoptosis. Furthermore, miR-221-3p overexpression decreased CDK4, Cyclin D1 and Bcl-2 and increased Bad expression, which was reversed by EIF5A2 overexpression. These results uncovered the tumor suppressive role of miR-221-3p in MB cell proliferation at least in part via targeting EIF5A2, suggesting that miR-221-3p might be a potential candidate target for diagnosis and therapeutics of MB.

eIF5A2 regulates the resistance of gastric cancer cells to cisplatin via induction of EMT

Cisplatin is the first-line chemotherapy drug for gastric cancer (GC), but treatment failure often occurs due to development of resistance. The mechanism of cisplatin resistance remains a mystery. Eukaryotic translation initiation factor 5A2 (eIF5A2) is an important tumor-promoting factor and has been rarely studied in GC. This study aimed to investigate the role of eIF5A2 in cisplatin resistance of GC cells and its relationship with epithelial-mesenchymal transition (EMT). We found that it is negative correlation between cisplatin resistance and eIF5A2's expression in GC cells. Silencing of eIF5A2 enhanced the sensitivity of GC cells to cisplatin, while overexpression of eIF5A2 decreased sensitivity. Cisplatin treatment induced gene expression changes consistent with EMT. EMT was blocked and the sensitivity of GC cells to cisplatin was increased by inhibiting the expression of Twist, indicating that EMT regulates the sensitivity of GC cells to cisplatin. Knockdown of eIF5A2 was associated with upregulation of the epithelial markers E-cadherin and β-catenin, while the expression of mesenchymal markers vimentin and N-cadherin decreased, indicating that eIF5A2 can reverse the EMT process and block the effect of cisplatin on EMT-related markers. Knockdown or overexpression of eIF5A2 did not affect the sensitivity of gastric cancer cells to cisplatin by Twist siRNA. Altogether, these data suggest that eIF5A2 regulates the resistance of gastric cancer cells to cisplatin by mediating EMT, and support the conclusion that eIF5A2 may be a molecular target for anti-tumor therapy.

Prognostic and clinical significance of metastasis-associated gene 1 overexpression in solid cancers: A meta-analysis

BACKGROUND

In the past 2 decades, metastasis-associated gene 1 (MTA1) has attracted attention for its close association with cancer progression and its roles in chromatin remodeling processes, making it a central gene in cancer. The present meta-analysis was performed to assess MTA1 expression in solid tumors.

MATERIALS AND METHODS

This analysis identified studies that evaluated the relationship between MTA1 expression and clinical characteristics or prognosis of patients with solid tumors via the PubMed, Cochrane Library, and Embase electronic databases. Fixed-effect and random-effect meta-analytical techniques were used to correlate MTA1 expression with outcome measures. The outcome variables are shown as odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

Analysis of 40 cohort studies involving 4564 cancer patients revealed a significant association of MTA1 overexpression with tumor patient age (>50 vs. <50 years: combined OR 0.73, 95% CI 0.57-0.94), tumor grade (G3/4 vs. G1/2: combined OR 1.94, 95% CI 1.48-2.53), tumor size (>3 cm vs. <3 cm: combined OR 2.35, 95% CI 1.73-3.19), T stage (T3/4 vs. T1/2: combined OR 2.11, 95% CI 1.74-2.56), lymph node metastasis (yes vs. no: combined OR 2.92, 95% CI 2.26-3.75), distant metastasis (yes vs. no: combined OR 2.26, 95% CI 1.42-3.59), TNM stage (III/IV vs. I/II: combined OR 2.50, 95% CI 1.84-3.38), vascular invasion (yes vs. no: combined OR 2.26, 95% CI 1.92-3.56), and poor overall survival time (HR 1.83; 95% CI: 1.53-2.20; P = .000).

CONCLUSIONS

Our analyses demonstrate that MTA1 was an effective predictor of a worse prognosis in tumor patients. Moreover, MTA1 may play important role in tumor progression and outcome, and targeting MTA1 may be a new strategy for anti-cancer therapy.

MicroRNA-9 Enhanced Cisplatin Sensitivity in Nonsmall Cell Lung Cancer Cells by Regulating Eukaryotic Translation Initiation Factor 5A2

We determined the role of microRNA (miR)-9 in regulating cisplatin chemoresistance in nonsmall cell lung cancer (NSCLC) cells. miR-9 and eukaryotic translation initiation factor 5A2 (eIF5A2) levels were examined by reverse transcription–quantitative PCR. Cell Counting Kit-8 and the 5-ethynyl-2′-deoxyuridine (EdU) assay were used to determine the effects of miR-9 mimic or inhibitor on NSCLC cell proliferation and viability, respectively. Bioinformatics was used to analyze the relationship between miR-9 and eIF5A2. Flow cytometry was used to analyze the percentage of apoptotic cells. miR-9 mimic enhanced cisplatin sensitivity, while miR-9 inhibitor produced the opposite result. eIF5A2 was identified as a potential target of miR-9, where miR-9 regulated eIF5A2 expression at mRNA and protein level. miR-9 mimic decreased the expression of eIF5A2 mRNA and protein, while miR-9 inhibitor increased eIF5A2 expression. eIF5A2 knockdown resolved the effects of miR-9 mimic or inhibitor on cisplatin sensitivity. miR-9 may be a potential biomarker for enhancing cisplatin sensitivity by regulating eIF5A2 in NSCLC cells.

Translation Factor eIF5A, Modification with Hypusine and Role in Regulation of Gene Expression. eIF5A as a Target for Pharmacological Interventions

Translation factor eIF5A participates in protein synthesis at the stage of polypeptide chain elongation. Two eIF5A isoforms are known that are encoded by related genes whose expression varies significantly in different tissues. The eIF5A1 isoform is a constitutively and ubiquitously expressed gene, while the eIF5A2 isoform is expressed in few normal tissues and is an oncogene by a number of parameters. Unique feature of eIF5A isoforms is that they are the only two proteins that contain amino acid hypusine. Modification with hypusine is critical requirement for eIF5A activity. Another distinctive feature of eIF5A is its involvement in the translation of only a subset of the total population of cell mRNAs. The genes for which mRNAs translation requires eIF5A are the members of certain functional groups and are involved in cell proliferation, apoptosis, inflammatory processes, and regulation of transcription and RNA metabolism. The involvement of eIF5A is necessary for the translation of proteins containing oligoproline fragments and some other structures. Modification of eIF5A by hypusine is implemented by two highly specialized enzymes, deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH), which are not involved in other biochemical reactions. Intracellular activity of these enzymes is closely associated with systems of protein acetylation, polyamine metabolism and other biochemical processes. Inhibition of DHS and DOHH activity provides the possibility of pharmacological control of eIF5A activity and expression of eIF5A-dependent genes.

Minority stress and leukocyte gene expression in sexual minority men living with treated HIV infection

Sexual minority (i.e., non-heterosexual) individuals experience poorer mental and physical health, accounted for in part by the additional burden of sexual minority stress occurring from being situated in a culture favoring heteronormativity. Informed by previous research, the purpose of this study was to identify the relationship between sexual minority stress and leukocyte gene expression related to inflammation, cancer, immune function, and cardiovascular function. Sexual minority men living with HIV who were on anti-retroviral medication, had viral load < 200 copies/mL, and had biologically confirmed, recent methamphetamine use completed minority stress measures and submitted blood samples for RNA sequencing on leukocytes. Differential gene expression and pathway analyses were conducted comparing those with clinically elevated minority stress (n = 18) and those who did not meet the clinical cutoff (n = 20), covarying reactive urine toxicology results for very recent stimulant use. In total, 90 differentially expressed genes and 138 gene set pathways evidencing 2-directional perturbation were observed at false discovery rate (FDR) < 0.10. Of these, 41 of the differentially expressed genes and 35 of the 2-directionally perturbed pathways were identified as functionally related to hypothesized mechanisms of inflammation, cancer, immune function, and cardiovascular function. The neuroactive-ligand receptor pathway (implicated in cancer development) was identified using signaling pathway impact analysis. Our results suggest several potential biological pathways for future work investigating the relationship between sexual minority stress and health.

Knockdown of EIF5A2 inhibits the malignant potential of non-small cell lung cancer cells

Eukaryotic translation initiation factor 5A2 (EIF5A2) has been demonstrated to be upregulated in numerous types of human cancer and is associated with cancer progression. However, the expression and role of EIF5A2 in non-small cell lung cancer (NSCLC) remains unclear. In the present study, the role of EIF5A2 in NSCLC was investigated, in addition to the underlying molecular mechanisms by which EIF5A2 acts. Relative EIF5A2 expression levels were determined in NSCLC cells and compared with levels in non-cancerous lung tissues. Short interfering (si)RNA targeted against EIF5A2 was used to knock down EIF5A2 levels in NSCLC cells. Cell proliferation, apoptosis rate, migration ability and invasion ability were determined in untreated and siRNA-treated NSCLC cells, in addition to the relative protein expression levels of various tumorigenic proteins and E-cadherin. EIF5A2 expression was significantly higher in NSCLC tissues compared with adjacent normal tissues. Knockdown of EIF5A2 in the NSCLC cells significantly inhibited cell proliferation and induced apoptosis. Furthermore, EIF5A2 silencing suppressed cell migratory and invasive capacities in vitro. Silencing of EIF5A2 in the NSCLC cells resulted in the downregulation of the tumorigenic proteins, apoptosis regulator Bcl-2 and myc proto-oncogene protein, and upregulation of E-cadherin, suggesting that EIF5A2 promotes proliferation and metastasis through these proteins. EIF5A2 may therefore serve as a novel therapeutic target for the treatment of NSCLC.

MicroRNA-599 inhibits metastasis and epithelial-mesenchymal transition via targeting EIF5A2 in gastric cancer

The reliable truth that exceptional miRNAs contribute to gastric cancer (GC) development and progression had been testified by researchers. However, the roles of various miRNAs in GC remain to be determined. In present research, we firmly believed that the expression of miR-599 in GC cell lines and tissues was declined. Clinical analysis disclosed that poor prognostic features, which incorporated lymph node metastasis and advanced TNM stage, could be expressively influenced by down-regulation of miR-599. For 5-year predicted-survival of GC patients, miR-599 was also confirmed to be a specialty prognostic marker. Notably, overmuch expression of miR-599 restricted cell migration, invasion and EMT progress, while down-regulated miR-599 reversed the effect in vitro and in vivo. Through directly binding to the 3'-UTR, miR-599 could possess EIF5A2 efficiently. In clinical samples of GC, miR-599 was inversely correlated with EIF5A2, which was upregulated in GC. The influence of miR-599 on migration, invasion and EMT progress could be partially discarded through alternation of EIF5A2 expression. Conclusively, our results manifested that miR-599 possessed the function of tumor suppressor gene in regulating EMT and metastasizing GC via targeting EIF5A2. Therefore, miR-599 has the capacity to become a therapeutic target and prognostic marker for GC.

N1-guanyl-1,7-diaminoheptane enhances the chemosensitivity of acute lymphoblastic leukemia cells to vincristine through inhibition of eif5a-2 activation

N1-guanyl-1,7-diaminoheptane (GC7), a deoxyhypusine synthase inhibitor, has been shown to exert antiproliferation effects in many solid tumors by regulating eukaryotic translation initiation factor 5a2 (eif5a-2). However, little is known about the role of GC7 and eif5a-2 in drug resistance in acute lymphoblastic leukemia (ALL). In the present study, we investigated the effect of GC7 on drug-resistant ALL and its potential mechanism. We found that using the CCK-8 assay that combined treatment with GC7 and vincristine (VCR) significantly inhibited the cell viability of two ALL cell lines. Using EdU incorporation assays and flow cytometry, we also showed that GC7 could markedly enhance the VCR sensitivity of ALL cells by suppressing cell proliferation and promoting apoptosis. Furthermore, we showed that GC7 could downregulate eif5a-2 and myeloid cell leukemia-1 (Mcl-1) expression. Knockdown of eif5a-2 inhibited the expression of Mcl-1 and significantly enhanced the VCR sensitivity. Moreover, eif5a-2 knockdown decreased the regulatory role of GC7 in increasing VCR sensitivity. Thus, our findings indicate that combined treatment with GC7 could enhance VCR sensitivity of ALL cells by regulating the eif5a-2/Mcl-1 axis. Together, our results highlight the potential clinical application of GC7 in VCR-based chemotherapy for the treatment of ALL.

Blocking Modification of Eukaryotic Initiation 5A2 Antagonizes Cervical Carcinoma via Inhibition of RhoA/ROCK Signal Transduction Pathway

Cervical carcinoma is one of the leading causes of cancer-related death for female worldwide. Eukaryotic initiation factor 5A2 belongs to the eukaryotic initiation factor 5A family and is proposed to be a key factor involved in the development of diverse cancers. In the current study, a series of in vivo and in vitro investigations were performed to characterize the role of eukaryotic initiation factor 5A2 in oncogenesis and metastasis of cervical carcinoma. The expression status of eukaryotic initiation factor 5A2 in 15 cervical carcinoma patients was quantified. Then, the effect of eukaryotic initiation factor 5A2 knockdown on in vivo tumorigenicity ability, cell proliferation, cell cycle distribution, and cell mobility of HeLa cells was measured. To uncover the mechanism driving the function of eukaryotic initiation factor 5A2 in cervical carcinoma, expression of members within RhoA/ROCK pathway was detected, and the results were further verified with an RhoA overexpression modification. The level of eukaryotic initiation factor 5A2 in cervical carcinoma samples was significantly higher than that in paired paratumor tissues ( P < .05). And the in vivo tumorigenic ability of HeLa cells was reduced by inhibition of eukaryotic initiation factor 5A2. Knockdown of eukaryotic initiation factor 5A2 in HeLa cells decreased the cell viability compared with normal cells and induced G1 phase cell cycle arrest ( P < .05). Moreover, the cell migration ability of eukaryotic initiation factor 5A2 knockdown cells was dramatically inhibited. Associated with alterations in phenotypes, RhoA, ROCK I, and ROCK II were downregulated. The above-mentioned changes in eukaryotic initiation factor 5A2 knockdown cells were alleviated by the overexpression of RhoA. The major findings outlined in the current study confirmed the potential of eukaryotic initiation factor 5A2 as a promising prognosis predictor and therapeutic target for cervical carcinoma treatment. Also, our data inferred that eukaryotic initiation factor 5A2 might function in carcinogenesis of cervical carcinoma through an RhoA/ROCK-dependent manner.

N1-guanyl-1, 7-diaminoheptane enhances the sensitivity of pancreatic ductal adenocarcinoma cells to gemcitabine via the inhibition of eukaryotic translation initiation factor 5A2

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy due to its broad resistance to chemotherapy. Gemcitabine is used as a standard chemotherapeutic drug for PDAC treatment, either alone or in combination with other chemotherapeutics. However, in patients with advanced disease, survival is rarely improved. This study aimed to investigate the therapeutic efficacy of N1-guanyl-1, 7-diaminoheptane (GC7) combined with gemcitabine in PDAC therapy. We measured eukaryotic translation initiation factor 5A2 (eIF5A2) expression and gemcitabine sensitivity in different PDAC cell lines (Panc-1, BxPC-3, and T3-M4). The synergistic cytotoxic effects of gemcitabine combined with GC7 were measured using Cell Counting Kit-8 assays. Western blots were performed to measure eIF5A2 and multi-drug resistance 1 (MDR1) protein expression in PDAC cells. The present findings demonstrated that combined treatment with GC7 and gemcitabine significantly inhibited PDAC cell line viability (P<0.05). EdU incorporation assays also indicated that GC7 co-treatment remarkably enhanced gemcitabine sensitivity in PDAC cells. Furthermore, downregulation of eIF5A2 diminished the regulatory role of GC7 in gemcitabine cytotoxicity. Western blotting data indicated that GC7 downregulated the expression of MDR1 while gemcitabine induced MDR1 upregulation. These findings showed that GC7 combination therapy may enhance the therapeutic efficacy of gemcitabine in PDAC by downregulating MDR1 expression.

Role of metastasis-associated protein 1 in prognosis of patients with digestive tract cancers: A meta-analysis

OBJECTIVES

Metastasis-associated protein 1 (MTA1) is a transcriptional regulator and significantly associated with prognosis of patients with cancer. However, its role as a potential prognostic marker in digestive tract cancer (DTC) is controversial. In this study, a meta-analysis was conducted to evaluate the MTA1 expression as a predictor of clinicopathology and survival of patients with DTC.

METHODS

We searched PubMed, Ovid, Web of Science and Cochrane databases using multiple search strategies for eligible studies. STATA 11.0 software was used to pool the data and analyze the association, odds ratios (ORs) and 95% confidence intervals (CIs) were used to measure the strength of the association. Furthermore, the Newcastle-Ottawa scale was used to evaluate the quality of eligible studies.

RESULTS

MTA1 overexpression was strongly associated with depth of invasion (OR = 1.88, 95%CI: 1.05-3.37, P = 0.03), lymph node metastasis (OR = 2.30, 95%CI: 1.76-3.01, P<0.001), vascular invasion (OR = 2.02, 95%CI: 1.40-2.91, P<0.001) and TNM stage (OR = 2.78, 95%CI: 1.63-4.74, P<0.001), and was related to 1- (RR = 1.84, 95%CI: 1.18-2.89, P = 0.008), 3- (RR = 1.74, 95%CI: 1.32-2.30, P<0.001) and 5-year (RR = 1.64, 95%CI: 1.18-2.27, P = 0.003) OS. Further, MTA1 was associated with 1- (RR = 4.16, 95%CI: 1.35-12.81, P = 0.01), 3- (RR = 1.90, 95%CI: 1.02-3.53, P = 0.04) and 5- (RR = 2.17, 95%CI: 1.41-3.32, P<0.001) year DFS. In subgroup analyses based on study quality and tumor type, MTA1 overexpression was obviously related to clinical parameters, such as lymph node metastasis and TNM stage, and was also associated with prognosis of patients with gastrointestinal or esophageal cancer.

CONCLUSIONS

MTA1 expression is strongly correlated with metastasis-related variables, and represents a promising prognostic factor in DTC.

Chromosomal Alterations and Gene Expression Changes Associated with the Progression of Leukoplakia to Advanced Gingivobuccal Cancer

We present an integrative genome-wide analysis that can be used to predict the risk of progression from leukoplakia to oral squamous cell carcinoma (OSCC) arising in the gingivobuccal complex (GBC). We find that the genomic and transcriptomic profiles of leukoplakia resemble those observed in later stages of OSCC and that several changes are associated with this progression, including amplification of 8q24.3, deletion of 8p23.2, and dysregulation of DERL3, EIF5A2, ECT2, HOXC9, HOXC13, MAL, MFAP5 and NELL2. Comparing copy number profiles of primary tumors with and without lymph-node metastasis, we identify alterations associated with metastasis, including amplifications of 3p26.3, 8q24.21, 11q22.1, 11q22.3 and deletion of 8p23.2. Integrative analysis reveals several biomarkers that have never or rarely been reported in previous OSCC studies, including amplifications of 1p36.33 (attributable to MXRA8), 3q26.31 (EIF5A2), 9p24.1 (CD274), and 12q13.2 (HOXC9 and HOXC13). Additionally, we find that amplifications of 1p36.33 and 11q22.1 are strongly correlated with poor clinical outcome. Overall, our findings delineate genomic changes that can be used in treatment management for patients with potentially malignant leukoplakia and OSCC patients with higher risk of lymph-node metastasis.

Targeting the polyamine-hypusine circuit for the prevention and treatment of cancer

The unique amino acid hypusine is present in only two proteins in eukaryotic cells, eukaryotic translation initiation factor 5A-1 (eIF5A1), and eIF5A2, where it is covalently linked to the lysine-50 residue of these proteins via a post-translational modification coined hypusination. This unique modification is directed by two highly conserved and essential enzymes, deoxyhypusine synthase (DHPS), and deoxyhypusine hydroxylase (DOHH), which selectively use the polyamine spermidine as a substrate to generate hypusinated eIF5A. Notably, elevated levels of polyamines are a hallmark of most tumor types, and increased levels of polyamines can also be detected in the urine and blood of cancer patients. Further, in-clinic agents that block the function of key biosynthetic enzymes in the polyamine pathway markedly impair tumor progression and maintenance of the malignant state. Thus, the polyamine pathway is attractive as a prognostic, prevention and therapeutic target. As we review, recent advances in our understanding of the specific functions of hypusinated eIF5A and its role in tumorigenesis suggest that the polyamine-hypusine circuit is a high priority target for cancer therapeutics.

Overexpression of eukaryotic initiation factor 5A2 (EIF5A2) is associated with cancer progression and poor prognosis in patients with early-stage cervical cancer

AIMS

As one of the only two isoforms of the eukaryotic initiation factor (EIF)5A family, EIF5A2 plays an important role in tumour progression and prognosis evaluation. The aim of this study was to investigate EIF5A2 expression in International Federation of Gynecology and Obstetrics (FIGO) stage I-II cervical cancer and to evaluate its clinical significance.

METHODS AND RESULTS

The mRNA and protein expression levels of EIF5A2 were analysed in 20 tissue samples of FIGO stage I-II cervical cancer and paired surrounding non-tumour cervical tissues by real-time polymerase chain reaction and western blot analysis. Immunohistochemistry was performed to examine EIF5A2 protein expression in paraffin-embedded tissues from 314 patients with cervical cancer. The mRNA and protein expression levels of EIF5A2 were significantly elevated in tumour tissues. The increased EIF5A2 expression was correlated with higher FIGO stage (P < 0.001), deep cervical stromal invasion (P = 0.026), lymphovascular space involvement (P = 0.002), pelvic lymph node metastasis (P < 0.001) and postoperative recurrence (P < 0.001) in patients with cervical cancer. Patients with tumours showing high EIF5A2 expression had a poorer survival time than those with normal EIF5A2 expression, especially the patients with negative pelvic lymph nodes and FIGO stage II. In addition, multivariate Cox analysis showed that high EIF5A2 expression was an independent prognostic factor for overall survival [hazard ratio 1.949; 95% confidence interval (CI) 1.116-3.404; P = 0.019] and disease-free survival (hazard ratio 1.980; 95% CI 1.189-3.297; P = 0.009).

CONCLUSIONS

EIF5A2 overexpression may contribute to cancer progression and poor prognosis. Therefore, EIF5A2 could be a novel potential prognostic marker for FIGO stage I-II cervical cancer.

Translation Initiation Factors: Reprogramming Protein Synthesis in Cancer

Control of mRNA translation plays a crucial role in the regulation of gene expression and is critical for cellular homeostasis. Dysregulation of translation initiation factors has been documented in several pathologies including cancer. Aberrant function of translation initiation factors leads to translation reprogramming that promotes proliferation, survival, angiogenesis, and metastasis. In such context, understanding how altered levels (and presumably activity) of initiation factors can contribute to tumor initiation and/or maintenance is of major interest for the development of novel therapeutic strategies. In this review we provide an overview of translation initiation mechanisms and focus on recent findings describing the role of individual initiation factors and their aberrant activity in cancer.

The Dysregulation of Polyamine Metabolism in Colorectal Cancer Is Associated with Overexpression of c-Myc and C/EBPβ rather than Enterotoxigenic Bacteroides fragilis Infection

Colorectal cancer is one of the most common cancers in the world. It is well known that the chronic inflammation can promote the progression of colorectal cancer (CRC). Recently, a number of studies revealed a potential association between colorectal inflammation, cancer progression, and infection caused by enterotoxigenic Bacteroides fragilis (ETBF). Bacterial enterotoxin activates spermine oxidase (SMO), which produces spermidine and H2O2 as byproducts of polyamine catabolism, which, in turn, enhances inflammation and tissue injury. Using qPCR analysis, we estimated the expression of SMOX gene and ETBF colonization in CRC patients. We found no statistically significant associations between them. Then we selected genes involved in polyamine metabolism, metabolic reprogramming, and inflammation regulation and estimated their expression in CRC. We observed overexpression of SMOX, ODC1, SRM, SMS, MTAP, c-Myc, C/EBPβ (CREBP), and other genes. We found that two mediators of metabolic reprogramming, inflammation, and cell proliferation c-Myc and C/EBPβ may serve as regulators of polyamine metabolism genes (SMOX, AZIN1, MTAP, SRM, ODC1, AMD1, and AGMAT) as they are overexpressed in tumors, have binding site according to ENCODE ChIP-Seq data, and demonstrate strong coexpression with their targets. Thus, increased polyamine metabolism in CRC could be driven by c-Myc and C/EBPβ rather than ETBF infection.

Eukaryotic translation initiation factor 5A2 regulates the migration and invasion of hepatocellular carcinoma cells via pathways involving reactive oxygen species

Eukaryotic translation initiation factor 5A2 (eIF5A2) has been identified as a critical gene in tumor metastasis. Research has suggested that reactive oxygen species (ROS) serve as signaling molecules in cancer cell proliferation and migration. However, the mechanisms linking eIF5A2 and ROS are not fully understood. Here, we investigated the effects of ROS on the eIF5A2-induced epithelial-mesenchymal transition (EMT) and migration in six hepatocellular carcinoma (HCC) cell lines. Western hybridization, siRNA transfection, transwell migration assays, wound-healing assays, and immunofluorescence analysis were used. The protein levels of eIF5A2 in tumor and adjacent tissue samples from 90 HCC patients with detailed clinical, pathological, and clinical follow-up data were evaluated. Overexpression of eIF5A2 was found in cancerous tissues compared with adjacent tissues. We found that eIF5A2 overexpression in HCC was associated with reduced overall survival. Knockdown of eIF5A2 and intracellular reduction of ROS significantly suppressed the invasion and metastasis of HCC cells. Interestingly, N1-guanyl-1, 7-diaminoheptane (GC7) suppressed the intracellular ROS levels. After blocking the EMT, administration of GC7 or N-acetyl-L-cysteine did not reduce cell migration further. Based on the experimental data, we concluded that inhibition of eIF5A2 alters progression of the EMT to decrease the invasion and metastasis of HCC cells via ROS-related pathways.

The chromosome 3q26 OncCassette: A multigenic driver of human cancer

Recurrent copy number variations (CNVs) are genetic alterations commonly observed in human tumors. One of the most frequent CNVs in human tumors involves copy number gains (CNGs) at chromosome 3q26, which is estimated to occur in >20% of human tumors. The high prevalence and frequent occurrence of 3q26 CNG suggest that it drives the biology of tumors harboring this genetic alteration. The chromosomal region subject to CNG (the 3q26 amplicon) spans from chromosome 3q26 to q29, a region containing ∼200 protein-encoding genes. The large number of genes within the amplicon makes it difficult to identify relevant oncogenic target(s). Whereas a number of genes in this region have been linked to the transformed phenotype, recent studies indicate a high level of cooperativity among a subset of frequently amplified 3q26 genes. Here we use a novel bioinformatics approach to identify potential driver genes within the recurrent 3q26 amplicon in lung squamous cell carcinoma (LSCC). Our analysis reveals a set of 35 3q26 amplicon genes that are coordinately amplified and overexpressed in human LSCC tumors, and that also map to a major LSCC susceptibility locus identified on mouse chromosome 3 that is syntenic with human chromosome 3q26. Pathway analysis reveals that 21 of these genes exist within a single predicted network module. Four 3q26 genes, SOX2, ECT2, PRKCI and PI3KCA occupy the hub of this network module and serve as nodal genes around which the network is organized. Integration of available genetic, genomic, biochemical and functional data demonstrates that SOX2, ECT2, PRKCI and PIK3CA are cooperating oncogenes that function within an integrated cell signaling network that drives a highly aggressive, stem-like phenotype in LSCC tumors harboring 3q26 amplification. Based on the high level of genomic, genetic, biochemical and functional integration amongst these 4 3q26 nodal genes, we propose that they are the key oncogenic targets of the 3q26 amplicon and together define a "3q26 OncCassette" that mediates 3q26 CNG-driven tumorigenesis. Genomic analysis indicates that the 3q26 OncCassette also operates in other major tumor types that exhibit frequent 3q26 CNGs, including head and neck squamous cell carcinoma (HNSCC), ovarian serous cancer and cervical cancer. Finally, we discuss how the 3q26 OncCassette represents a tractable target for development of novel therapeutic intervention strategies that hold promise for improving treatment of 3q26-driven cancers.

MiR-30b suppresses tumor migration and invasion by targeting EIF5A2 in gastric cancer

AIM

To elucidate the potential biological role of miR-30b in gastric cancer and investigate the underlying molecular mechanisms of miR-30b to inhibit metastasis of gastric cancer cells.

METHODS

The expression of miR-30b was detected in gastric cancer cell lines and samples by reverse transcription-polymerase chain reaction. CCK-8 assays were conducted to explore the impact of miR-30b overexpression on the proliferation of gastric cancer cells. Flow cytometry was used to examine the effect of miR-30b on the apoptosis. Transwell test was used for the migration and invasion assays. Luciferase reporter assays and Western blot were employed to validate regulation of putative target of miR-30b.

RESULTS

The results showed that miR-30b was downregulated in gastric cancer tissues and cancer cell lines and functioned as a tumor suppressor. Overexpression of miR-30b promoted cell apoptosis, and suppressed proliferation, migration and invasion of the gastric cancer cell lines AGS and MGC803. Bioinformatic analysis identified the 3'-untranslated region of eukaryotic translation initiation factor 5A2 (EIF5A2) as a putative binding site of miR-30b. Luciferase reporter assays and Western blot analysis confirmed the EIF5A2 gene as a target of miR-30b. Moreover, expression levels of the EIF5A2 targets E-cadherin and Vimentin were altered following transfection of miR-30b mimics.

CONCLUSION

Our findings describe a link between miR-30b and EIF5A2, which plays an important role in mediating epithelial-mesenchymal transition.

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.