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

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.

MicroRNA-577/EIF5A2 axis suppressed the proliferation of DDP-resistant nasopharyngeal carcinoma cells by blocking TGF-β signaling pathway

Diaminodichoroplatinum (DDP) resistance of tumor cells is the culprit of nasopharyngeal carcinoma (NPC) treatment failure. MicroRNA-577 is lowly expressed in NPC tissues, but relevant mechanism is poorly studied. Therefore, this study investigated the role of microRNA-577 in NPC cells with DDP resistance and its mechanism. DDP-resistant NPC cells were established by treatment with DDP at increased concentrations (2, 4, 6, 8, or 10 μg/mL). MicroRNA-577 and EIF5A2 mRNA expressions were detected by qRT-PCR. Cell biological behaviors were assessed via cell function experiments. Expressions of epithelial mesenchymal transformation (EMT)-related proteins were quantified by western blot. The targeting relationship between eukaryotic translation initiation factor 5A2 (EIF5A2) and microRNA-577 was verified through dual-luciferase reporter assay. The tumor volume and weight were measured after subcutaneous tumorigenesis in mice. As observed from the results, microRNA-577 expression was reduced in NPC cells and DDP-resistant NPC cells. Up-regulated microRNA-577 suppressed the malignant behaviors and EMT of DDP-resistant NPC cells, and facilitated cell apoptosis. MicroRNA-577 targeted EIF5A2, and overexpressed EIF5A2 reversed the above effects of up-regulated microRNA-577 on DDP-resistant NPC cells. Besides, EIF5A2 positively regulated TGF-β signaling pathway, and TGF-β treatment offset the promoting effects of EIF5A2 silencing on apoptosis of DDP-resistant NPC cells. Up-regulated microRNA-577 suppressed the proliferation of DDP-resistant NPC cells, and down-regulated the levels of EIF5A2 and TGF-β as well as EMT in vivo. Collectively, microRNA-577/EIF5A2 axis hinders the EMT progression through the blockage of TGF-β signaling pathway, so as to inhibit the proliferation of DDP-resistant NPC.

High levels of hypusinated eIF5A in leiomyoma and leiomyosarcoma pathologies: a possible novel therapeutic target

RESEARCH QUESTION

Is the hypusinated form of the eukaryotic translation initiation factor 5A (EIF5A) present in human myometrium, leiomyoma and leiomyosarcoma, and does it regulate cell proliferation and fibrosis?

DESIGN

The hypusination status of eIF5A in myometrial and leiomyoma patient-matched tissues was evaluated by immunohistochemistry and Western blotting as well as in leiomyosarcoma tissues by immunohistochemistry. Myometrial, leiomyoma and leiomyosarcoma cell lines were treated with N1-guanyl-1,7-diaminoheptane (GC-7), responsible for the inhibition of the first step of eIF5A hypunization, and the proliferation rate was determined by MTT assay; fibronectin expression was analysed by Western blotting. Finally, expression of fibronectin in leiomyosarcoma tissues was detected by immunohistochemistry.

RESULTS

The hypusinated form of eIF5A was present in all tissues examined, with an increasing trend of hypusinated eIF5A levels from normal myometrium to neoplastic benign leiomyoma up to neoplastic malignant leiomyosarcoma. The higher levels in leiomyoma compared with myometrium were confirmed by Western blotting (P = 0.0046). The inhibition of eIF5A hypusination, with GC-7 treatment at 100 nM, reduced the cell proliferation in myometrium (P = 0.0429), leiomyoma (P = 0.0030) and leiomyosarcoma (P = 0.0044) cell lines and reduced the expression of fibronectin in leiomyoma (P = 0.0077) and leiomyosarcoma (P = 0.0280) cells. The immunohistochemical staining of leiomyosarcoma tissue revealed that fibronectin was highly expressed in the malignant aggressive (central) part of the leiomyosarcoma lesion, where hypusinated eIF5A was also highly represented.

CONCLUSIONS

These data support the hypothesis that eIF5A may be involved in the pathogenesis of myometrial benign and malignant pathologies.

New K50R mutant mouse models reveal impaired hypusination of eif5a2 with alterations in cell metabolite landscape

The eukaryotic translation initiation factor 5A1 (eIF5A1) and 5A2 (eIF5A2) are important proteins in a variety of physiological and pathophysiological processes and their function has been linked to neurodevelopmental disorders, cancer, and viral infections. Here, we report two new genome-edited mouse models, generated using a CRISPR-Cas9 approach, in which the amino acid residue lysine 50 is replaced with arginine 50 (K50R) in eIF5A1 or in the closely related eIF5A2 protein. This mutation prevents the spermidine-dependent post-translational formation of hypusine, a unique lysine derivative that is necessary for activation of eIF5A1 and eIF5A2. Mouse brain lysates from homozygous eif5a2-K50R mutant mice (eif5a2K50R/K50R) confirmed the absence of hypusine formation of eIF5A2, and metabolomic analysis of primary mouse dermal fibroblasts revealed significant alterations in the metabolite landscape compared to controls including increased levels of tryptophan, kyrunenine, pyridoxine, nicotinamide adenine dinucleotide, riboflavin, flavin adenine dinucleotide, pantothenate, and coenzyme A. Further supported by new publicly available bioinformatics data, these new mouse models represent excellent in vivo models to study hypusine-dependent biological processes, hypusination-related disorders caused by eIF5A1 and eIF5A2 gene aberrations or mRNA expression dysregulation, as well as several major human cancer types and potential therapies.

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 interface stiffness and topographic feature dictate interfacial invasiveness of cancer spheroids

During cancer metastasis, tumor cells likely navigate, in a collective manner, discrete tissue spaces comprising inherently heterogeneous extracellular matrix microstructures where interfaces may be frequently encountered. Studies have shown that cell migration modes can be determined by adaptation to mechanical/topographic cues from interfacial microenvironments. However, less attention has been paid to exploring the impact of interfacial mechnochemical attributes on invasive and metastatic behaviors of tumor aggregates. Here, we excogitated a collagen matrix-solid substrate interface platform to investigate the afore-stated interesting issue. Our data revealed that stiffer interfaces stimulated spheroid outgrowth by motivating detachment of single cells and boosting their motility and velocity. However, stronger interfacial adhesive strength between matrix and substrate led to the opposite outcomes. Besides, this interfacial parameter also affected the morphological switch between migration modes of the detached cells and their directionality. Mechanistically, myosin II-mediated cell contraction, compared to matrix metalloproteinases-driven collagen degradation, was shown to play a more crucial role in the invasive outgrowth of tumor spheroids in interfacial microenvironments. Thus, our findings highlight the importance of heterogeneous interfaces in addressing and combating cancer metastasis.

High eukaryotic initiation factor 5A2 expression predicts poor prognosis and may participate in the SNHG16/miR-10b-5p/EIF5A2 regulatory axis in head and neck squamous cell carcinoma

BACKGROUND

This study attempted to investigate the significance of eukaryotic initiation factor 5A2 (EIF5A2) in the prognosis and regulatory network of head and neck squamous cell carcinoma (HNSCC).

METHODS

EIF5A2 expression, prognostic information, and methylation levels of HNSCC were collected from the Cancer Genome Atlas (TCGA) database. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to determine EIF5A2 levels in HNSCC and normal tissue samples. R software was employed for expression analysis and prognosis assessment of EIF5A2 in HNSCC. A competing endogenous RNA (ceRNA) network was generated with the starBase database. Gene set enrichment analysis (GSEA) was used to determine the enriched physiological functions and network related to high expression of EIF5A2 in HNSCC. Immune infiltration-related outcomes were acquired from the CIBERSORT and Tumor Immune Estimation Resource (TIMER) database.

RESULTS

EIF5A2 overexpression was observed in HNSCC and linked to poor progression-free survival and overall survival time. Cox regression analyses showed that EIF5A2 level was a stand-alone indicator of HNSCC patients' prognosis. A ceRNA network analysis highlighted the SNHG16/miR-10b-5p/EIF5A2 axis in EIF5A2 regulation. The GSEA results indicated that EIF5A2 was involved in complex signaling pathways. The CIBERSORT and TIMER databases revealed significant associations between EIF5A2 expression and immune cell infiltration.

CONCLUSION

EIF5A2 overexpression may be a risk factor for prognosis in HNSCC and may be regulated by the SNHG16/miR-10b-5p/EIF5A2 axis.

Eukaryotic initiation factor 5A2 mediates hypoxia-induced autophagy and cisplatin resistance

Hypoxia-induced cisplatin resistance is a major challenge during non-small cell lung cancer (NSCLC) treatment. Based on previous studies, we further explored the effect of eukaryotic initiation factor 5A2 (eIF5A2) in hypoxia-induced cisplatin resistance. In this study, we found that autophagy and cisplatin resistance were increased under hypoxic conditions in three different NSCLC cell lines. Compared with that under normoxic conditions, dramatic upregulation of eIF5A2 and hypoxia inducible factor 1 subunit alpha (HIF-1α) levels were detected under hypoxia exposure. Small interfering RNA silencing of HIF-1α resulted in decreased expression of eIF5A2, indicating that eIF5A2 acts downstream of HIF-1α. In addition, the expression of eIF5A2 was significantly higher in NSCLC tumors compared with that in normal tissues. RNA silencing-mediated downregulation of eIF5A2 decreased hypoxia-induced autophagy, thereby reducing hypoxia-induced cisplatin resistance in NSCLC cells. The roles of eIF5A2 in cisplatin resistance were further validated in vivo. Combined treatment using eIF5A2-targeted downregulation together with cisplatin significantly inhibited tumor growth compared with cisplatin alone in the subcutaneous mouse model. In conclusions, eIF5A2 overexpression is involved in hypoxia-induced autophagy during cisplatin resistance. We suggest that a combination of eIF5A2 targeted therapy and cisplatin chemotherapy is probably an effective strategy to reverse hypoxia-induced cisplatin resistance and inhibit NSCLC development.

Eukaryotic Initiation Factor 5A2 Regulates Expression of Antiviral Genes

Translation factors are essential for regulation of protein synthesis. The eukaryotic translation initiation factor 5A (eIF5A) family is made up of two paralogues - eIF5A1 and eIF5A2 - which display high sequence homology but distinct tissue tropism. While eIF5A1 directly binds to the ribosome and regulates translation initiation, elongation, and termination, the molecular function of eIF5A2 remains poorly understood. Here, we engineer an eIF5A2 knockout allele in the SW480 colon cancer cell line. Using ribosome profiling and RNA-Sequencing, we reveal that eIF5A2 is functionally distinct from eIF5A1 and does not regulate transcript-specific or global protein synthesis. Instead, eIF5A2 knockout leads to decreased intrinsic antiviral gene expression, including members of the IFITM and APOBEC3 family. Furthermore, cells lacking eIF5A2 display increased permissiveness to virus infection. Our results uncover eIF5A2 as a factor involved regulating the antiviral transcriptome, and reveal an example of how gene duplications of translation factors can result in proteins with distinct functions.

Epigenetic activation of RBM15 promotes clear cell renal cell carcinoma growth, metastasis and macrophage infiltration by regulating the m6A modification of CXCL11

Clear cell renal cell carcinoma (ccRCC) is a common kidney malignancy that is characterized by poor prognosis. RNA-binding motif protein 15 (RBM15) has been identified as an oncogene in multiple tumors. Nevertheless, the function and mechanism of RBM15 in ccRCC are not clear. In this study, RBM15 was found to be upregulated in ccRCC cells and tissues. RBM15 enhanced the proliferation, clone formation, migration, invasion and epithelial-interstitial transition of ccRCC cells. Enhanced RBM15 was caused by the abundant histone 3 acetylation modification of the RBM15 promoter induced by EP300/CBP. RBM15 enhanced the stability of CXCL11 mRNA in an m6A-dependent manner. Moreover, RBM15 was found to promote macrophage infiltration and M2 polarization by promoting the secretion of CXCL11 in ccRCC cells in vitro and in vivo. Our findings highlight the function of RBM15 in ccRCC and reveal a novel identified EP300/CBP-RBM15-CXCL11 signaling axis, which promotes ccRCC progression and provides new insight into ccRCC therapy.

Androgen receptor regulates eIF5A2 expression and promotes prostate cancer metastasis via EMT

Androgen receptor (AR) is an androgen-activated transcription factor of the nuclear receptor superfamily. AR plays a role in the development and progression of prostate cancer (PCa). However, the exact role of AR in PCa metastasis remains unclear. In the present study, we aimed to elucidate the function of AR in PCa. We found that eukaryotic translation initiation factor (EIF) 5A2, an elongation factor that induces epithelial-to-mesenchymal transition (EMT) in PCa cells, was significantly upregulated after 5α-dihydrotestosterone (DHT) stimulation and downregulated after anti‐androgen bicalutamide treatment in PCa cells with high AR expression, but not in cells with low AR expression. Moreover, eIF5A2 knockdown could eliminate DHT-induced invasion and migration of AR-positive PCa cells. DHT treatment decreased epithelial expression of E‐cadherin and β-catenin but increased the expression of the mesenchymal marker proteins Vimentin and N-cadherin. DHT therefore induced EMT, and knockdown of eIF5A2 inhibited DHT-induced EMT. Moreover, in vivo study, Luciferase signals from the lungs of the eIF5A2 plasmid group indicated higher metastasis ability, and the eIF5A2 siRNA group had lower metastasis ability. Our results suggest that AR positively regulates eIF5A2 expression in androgen-dependent cells, and stimulation of AR expression and signaling in prostate tumors promotes PCa metastasis by EMT induction and upregulation of eIF5A2.

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.

EIF5A2 controls ovarian tumor growth and metastasis by promoting epithelial to mesenchymal transition via the TGFβ pathway

BACKGROUND

Epithelial to mesenchymal transition (EMT) contributes to tumor metastasis and chemoresistance. Eukaryotic initiation factor 5A2 (EIF5A2) is highly expressed in a variety of human cancers but rarely expressed in normal tissues. While EIF5A2 has oncogenic activity in several cancers and contributes to tumor metastasis, its role in ovarian cancer is unknown. In this study, we investigate whether EIF5A2 contributes to ovarian tumor metastasis by promoting EMT.

METHODS

To investigate the role of EIF5A2, we knocked out (KO) EIF5A2 using lentiviral CRISPR/Cas9 nickase in high invasive SKOV3 and OVCAR8 cells and overexpressed EIF5A2 in low invasive OVCAR3 cells using lentiviral vector. Cell proliferation, migration and invasion was examined in vitro ovarian cancer cells and tumor metastasis was evaluated in vivo using orthotopic ovarian cancer mouse models.

RESULTS

Here we report that EIF5A2 is highly expressed in ovarian cancers and associated with patient poor survival. Lentiviral CRISPR/Cas9 nickase vector mediated knockout (KO) of EIF5A2 inhibits epithelial to mesenchymal transition (EMT) in SKOV3 and OVCAR8 ovarian cancer cells that express high levels of EIF5A2. In contrast, overexpression of EIF5A2 promotes EMT in OVCAR3 epithelial adenocarcinoma cells that express relatively low EIF5A2 levels. KO of EIF5A2 in SKOV3 and OVCAR8 cells inhibits ovarian cancer cell migration and invasion, while its overexpression promotes cell migration and invasion in OVCAR3 adenocarcinoma cells. We further demonstrate that EIF5A2 promotes EMT by activating the TGFβ pathway and KO of EIF5A2 inhibits ovarian tumor growth and metastasis in orthotopic ovarian cancer mouse models.

CONCLUSION

Our results indicate that EIF5A2 is an important controller of ovarian tumor growth and metastasis by promoting EMT and activating the TGFβ pathway.

EIF5A2 Is Highly Expressed in Anaplastic Thyroid Carcinoma and Is Associated With Tumor Growth by Modulating TGF- Signals

Anaplastic thyroid carcinoma (ATC) is resistant to standard therapies and has no effective treatment. Eukaryotic translation initiation factor 5A2 (EIF5A2) has shown to be upregulated in many malignant tumors and proposed to be a critical gene involved in tumor metastasis. In this study, we aimed to investigate the expression status of EIF5A2 in human ATC tissues and to study the role and mechanisms of EIF5A2 in ATC tumorigenesis in vitro and in vivo. Expression of EIF5A2 protein was analyzed in paraffin-embedded human ATC tissues and adjacent nontumorous tissues (ANCT) (n=24) by immunochemistry. Expressions of EIF5A2 mRNA and protein were analyzed in fresh-matched ATC and ANCT (n=23) and ATC cell lines by real-time polymerase chain reaction (PCR) and Western blotting. The effect of targeting EIF5A2 with short hairpin RNA (shRNA) or EIF5A2 overexpression on the ATC tumorigenesis and TGF-/Smad2/3 signals in vitro and in vivo was investigated. Expression of EIF5A2 was significantly upregulated in ATC tissues and cell lines compared with ANCT and normal follicular epithelial cell line. Functional studies found that targeting EIF5A2 induced SW1736 cell death in vitro and in vivo, followed by significantly downregulated phosphorylation of Smad2/3 (p-Smad2/3) in SW1736 cells at the protein level. Ectopic expression of EIF5A2 could promote 8505C cell growth in vitro and in vivo, followed by significantly upregulated p-Smad3 at the protein level. Recombinant human TGF-1 (hTGF-1) treatment decreased the antiproliferative activity of the EIF5A2 downexpressing 8505C cells through reversing pSmad2/3. Using the specific inhibitor SB431542 to block TGF- pathway or Smad3 siRNA to knock down Smad3 increased the antiproliferative activity of the EIF5A2-overexpressing 8505C cells through inhibiting pSmad2/3. Our findings indicated that EIF5A2 controled cell growth in ATC cells, and EIF5A/TGF-/Smad2/3 signal may be a potential therapeutic target for ATC 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.

Role of JAK/STAT3 Signaling in the Regulation of Metastasis, the Transition of Cancer Stem Cells, and Chemoresistance of Cancer by Epithelial-Mesenchymal Transition

The JAK/STAT3 signaling pathway plays an essential role in various types of cancers. Activation of this pathway leads to increased tumorigenic and metastatic ability, the transition of cancer stem cells (CSCs), and chemoresistance in cancer via enhancing the epithelial–mesenchymal transition (EMT). EMT acts as a critical regulator in the progression of cancer and is involved in regulating invasion, spread, and survival. Furthermore, accumulating evidence indicates the failure of conventional therapies due to the acquisition of CSC properties. In this review, we summarize the effects of JAK/STAT3 activation on EMT and the generation of CSCs. Moreover, we discuss cutting-edge data on the link between EMT and CSCs in the tumor microenvironment that involves a previously unknown function of miRNAs, and also discuss new regulators of the JAK/STAT3 signaling pathway.

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.

Targeting eIF5A2 inhibits prostate carcinogenesis, migration, invasion and metastasis in vitro and in vivo

Overexpression of eukaryotic initiation factor- 5A2 (eIF5A2) has been implicated in promoting tumor cell migration and invasion in many cancers. However, whether eIF5A2 could be as the target for prostate cancer (PCa) treatment is still unknown. In this study, small interfering RNA specific for eIF5A2 (eIF5A2 siRNA) and lentivector for eIF5A2 shRNA (Lv-eIF5A2 shRNA) was performed to down-regulate eIF5A2 expression in PCa PC-3 M IE8 cells and in animal tumor model, respectively. The biological function of eIF5A2 siRNA or Lv-eIF5A2 shRNA on PC-3 M IE8 cell growth, apoptosis, migration, invasion and lung metastasis were explored. The results showed that targeting eIF5A2 inhibited PC-3 M IE8 cell invasion, migration, proliferation and increased cell apoptosis in vitro, and inhibited tumor growth and lung metastasis in vivo. Analysis of eIF5A2 signaling pathways in the clonal derivatives showed a decrease in MMP-2 and MMP-9 activation and increase in bcl-2 expression. We therefore concluded that therapies targeting the eIF5A2 signaling pathway may be more effective to prevent organ metastasis and primary tumor formation.

TGF-β and microRNA Interplay in Genitourinary Cancers

Genitourinary cancers (GCs) include a large group of different types of tumors localizing to the kidney, bladder, prostate, testis, and penis. Despite highly divergent molecular patterns, most GCs share commonly disturbed signaling pathways that involve the activity of TGF-β (transforming growth factor beta). TGF-β is a pleiotropic cytokine that regulates key cancer-related molecular and cellular processes, including proliferation, migration, invasion, apoptosis, and chemoresistance. The understanding of the mechanisms of TGF-β actions in cancer is hindered by the "TGF-β paradox" in which early stages of cancerogenic process are suppressed by TGF-β while advanced stages are stimulated by its activity. A growing body of evidence suggests that these paradoxical TGF-β actions could result from the interplay with microRNAs: Short, non-coding RNAs that regulate gene expression by binding to target transcripts and inducing mRNA degradation or inhibition of translation. Here, we discuss the current knowledge of TGF-β signaling in GCs. Importantly, TGF-β signaling and microRNA-mediated regulation of gene expression often act in complicated feedback circuits that involve other crucial regulators of cancer progression (e.g., androgen receptor). Furthermore, recently published in vitro and in vivo studies clearly indicate that the interplay between microRNAs and the TGF-β signaling pathway offers new potential treatment options for GC patients.

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.

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.

MicroRNA-9 enhances sensitivity to cetuximab in epithelial phenotype hepatocellular carcinoma cells through regulation of the eukaryotic translation initiation factor 5A-2

Hepatocellular carcinoma (HCC) is one of the most widespread malignant human tumors worldwide. Treatment options include radiotherapy, surgical intervention and chemotherapy; however, drug resistance is an ongoing treatment concern. In the present study, the effects of a microRNA (miR/miRNA), miR-9, on the sensitivity of HCC cell lines to the epidermal growth factor receptor inhibitor, cetuximab, were examined. miR-9 has been proposed to serve a role in tumorigenesis and tumor progression. In the present study, bioinformatics analyses identified the eukaryotic translation initiation factor 5A2 (eIF-5A-2) as a target of miR-9. The expression levels of miR-9 and eIF-5A-2 were examined by reverse transcription-quantitative polymerase chain reaction and HCC cell lines were transfected with miR-9 mimics and inhibitors to determine the effects of the miRNA on cell proliferation and viability. The miR-9 mimic was revealed to significantly increase the sensitivity of epithelial phenotype HCC cells (Hep3B and Huh7) to cetuximab, while the miR-9 inhibitor triggered the opposite effect. There were no significant differences in sensitivity to cetuximab observed in mesenchymal phenotype HCC cells (SNU387 and SNU449). Cells lines displaying high expression levels of eIF-5A-2 were more resistant to cetuximab. Transfection of cells with a miR-9 mimic resulted in downregulation of the expression of eIF-5A-2 mRNA, while an miR-9 inhibitor increased expression. When expression of eIF-5A-2 was knocked down with siRNA, the effects of miR-9 on cetuximab sensitivity were no longer observed. Taken together, these data support a role for miR-9 in enhancing the sensitivity of epithelial phenotype HCC cells to cetuximab through regulation of eIF-5A-2.

RIN1 promotes renal cell carcinoma malignancy by activating EGFR signaling through Rab25

We previously identified the important role of RIN1 expression in the prognosis of clear cell renal cell carcinoma (ccRCC). The role of RIN1 in ccRCC malignancy and underlying molecular mechanisms remain unclear. Here we report that ccRCC cells and tissues expressed more RIN1 than normal controls. Gain‐of‐function and loss‐of‐function studies demonstrated that RIN1 enhanced ccRCC cell growth, migration and invasion abilities in vitro and promoted tumor growth and metastasis in vivo. Mechanistic studies revealed that RIN1 has an activating effect on EGFR signaling in ccRCC. In addition, we unveil Rab25, a critical GTPase in ccRCC malignancy, as a functional RIN1 interacting partner. Knockdown of Rab25 eliminated the augmentation of carcinoma cell proliferation, migration and invasion by ectopic RIN1. We also confirmed that RIN1 and Rab25 expression correlates with the overall‐survival of ccRCC patients from TCGA. These findings suggest that RIN1 plays an important oncogenic role in ccRCC malignancy by activation of EGFR signaling through interacting with Rab25, and RIN1 could be employed as an effective therapeutic target for ccRCC.

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.

Role of STAT3 and FOXO1 in the Divergent Therapeutic Responses of Non-metastatic and Metastatic Bladder Cancer Cells to miR-145

Although miR-145 is the most frequently downregulated miRNA in bladder cancer, its exact stage association and downstream effector have not been defined. Here, we found that miR-145 was upregulated in human patients with bladder cancer with lymph node metastasis and in metastatic T24T cell line. Forced expression of miR-145 promoted anchorage-independent growth of T24T cells accompanied by the downregulation of forkhead box class O1 (FOXO1). In contrast, in non-metastatic T24 cells, miR-145 overexpression inhibited cell growth with upregulation of FOXO1, and the knockdown of FOXO1 abolished the miR-145-mediated inhibition of cell growth. Mechanistic studies revealed that miR-145 directly bound to and attenuated 3'-untranslated region (UTR) activity of foxo1 mRNA in both T24 and T24T cells. Interestingly, miR-145 suppressed STAT3 phosphorylation at Tyr705 and increased foxo1 promoter transcriptional activity in T24 cells, but not in T24T cells, suggesting a role of STAT3 in the divergent responses to miR-145. Supporting this was our finding that STAT3 knockdown mimicked miR-145-mediated upregulation of FOXO1 in T24T cells and inhibition of anchorage-independent growth. Consistently, ectopic expression of miR-145 promoted tumor formation of xenograft T24T cells, whereas such promoting effect became inhibitory due to specific knockdown of STAT3. Together, our findings demonstrate the stage-specific association and function of miR-145 in bladder cancers and provide novel insights into the therapeutic targeting of miR-145. Mol Cancer Ther; 16(5); 924-35. ©2017 AACR.

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.

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.

Understanding the biology of urothelial cancer metastasis

Management of unresectable urothelial cancer (UC) has been a clinical challenge for decades. While drug resistance is a key issue, precise understanding of biology of UC metastasis is another challenge for the improvement of treatment outcome of UC patients. Introduction of the cell biology concepts including epithelial-mesenchymal transition (EMT) and cancer stemness seems to explain UC metastasis. Molecular genetics based on gene expression profiling, next generation sequencing, and explosion of non-coding RNA world has opened the door to intrinsic molecular subtyping of UC. Next steps include, based on the recently accumulated understanding, the establishment of novel disease models representing UC metastasis in various experimental platforms, particularly in vivo animal systems. Indeed, novel knowledge molecular genetics has not been fully linked to the modeling of UC metastasis. Further understanding of bladder carcinogenesis is needed particularly with regard to cell of origin related to tumor characteristics including driver gene alterations, pathological differentiations, and metastatic ability. Then we will be able to establish better disease models, which will consequently lead us to further understanding of biology and eventually the development of novel therapeutic strategies for UC metastasis.

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.

Expression of EIF5A2 associates with poor survival of nasopharyngeal carcinoma patients treated with induction chemotherapy

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a type of head-neck cancer with a distinguishable geographic and racial distribution worldwide. Increasing evidence supports that the accumulation of additional genetic and epigenetic abnormalities is important in driving the NPC tumorigenic process. In this study, we aim to investigate the association between EIF5A2 (Eukaryotic translation initiation factor 5A2) expression status and NPC clinical outcomes.

METHODS

The expression status of EIF5A2 was investigated in the NPC tissue microarray. Tissues were from 166 NPC patients staging II-IV, collected between 1999 and 2005. All patients were administered 2-3 cycles of DDP (cisplatin) + 5-Fu (5-fluorouracil) induction therapy and then treated with a uniform conventional two-dimensional radiotherapy. Cell motility assay, tumor growth assay and cytotoxicity assay were performed on the EIF5A2 overexpressed cells and control cells. siRNA was also used in the in vitro studies.

RESULTS

Positive staining of EIF5A2 was observed in 85.4 % (105/123) informative tumor cases. Multivariate analyses demonstrated that EIF5A2 was an independent prognostic marker of poor overall survival (OS) (P = 0.041), failure-free survival (FFS) (P = 0.029), and distant failure-free survival (D-FFS) (P = 0.043) in patients with locoregionally advanced NPC patients treated with cisplatin + 5-Fu chemoradiotherapy. The forced expression of EIF5A2 in NPC cells enhanced the cells' motility and growth ability. Knock-down of EIF5A2 in NPC cells decreased the cell's motility and growth ability. Our results also demonstrated that EIF5A2 overexpression induced chemoresistance of NPC cells to 5-Fu.

CONCLUSIONS

Our findings suggested that EIF5A2 expression, as examined by immunohistochemistry, could function as an independent prognostic factor of outcomes in NPC patients with cisplatin + 5-Fu chemoradiotherapy. EIF5A2 might be a novel therapeutic target for the inhibition of NPC progress.

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.

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.

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 hypusine cascade promotes cancer progression and metastasis through the regulation of RhoA in squamous cell carcinoma

Metastasis is a critical factor contributing to poor prognosis in cancer, but the underlying mechanisms of metastasis are still poorly understood. We established a highly metastatic cell subline (HOC313-LM) derived from an oral squamous cell carcinoma cell line (HOC313) for uncovering the mechanisms of metastasis, and identified deoxyhypusine synthase (DHPS) as a metastasis-associated gene within the specific amplification at 19p13.2-p13.13 in HOC313-LM. DHPS-mediated hypusine-modification of eukaryotic translation factor 5A facilitated the translation of RhoA, resulting in the activation of the RhoA signaling pathway and leading to not only increased cell motility, invasion and metastasis of cancer cells in vitro, but also increased tumor growth in vivo. Moreover, the use of N1-Guanyl-1,7-diaminoheptane, a DHPS inhibitor, resulted in a significant decrease in tumor formation in vivo. In patients with esophageal squamous cell carcinoma (ESCC), overexpression of DHPS in ESCC tumors was significantly associated with worse recurrence-free survival, and correlated with distant metastasis. The elucidation of these molecular mechanisms within the hypusine cascade suggests opportunities for novel therapeutic targets in SCC.

A comprehensive characterization of cell cultures and xenografts derived from a human verrucous penile carcinoma

This study aimed to establish and characterize primary cell cultures and xenografts derived from penile carcinoma (PeCa) in order to provide experimental models for cellular processes and efficacy of new treatments. A verrucous squamous cell carcinoma (VSCC) was macrodissected, dissociated, and cultivated in KSFM/DF12 medium. Cell cultures were evaluated at passage 5 (P5) using migration and invasion assays and were serially propagated, in vivo, in BALB/c nude mice until passage 3 (X1-X3). Immunophenotypic characterization of cultures and xenografts was performed. Genomic (CytoScan HD, Affymetrix) and transcriptomic profiles (HTA 2.0 platform, Affymetrix) for VSCC, cell cultures, and xenografts were assessed. P5 cells were able to migrate, invade the Matrigel, and produce tumors in immunodeficient mice, demonstrating their malignant potential. The xenografts unexpectedly presented a sarcomatoid-like carcinoma phenotype. Genomic analysis revealed a high similarity between the VSCC and tumor-derived xenograft, confirming its xenograft origin. Interestingly, a subpopulation of P5 cells presented stem cell-related markers (CD44(+)CD24(-) and ALDH1(high)) and sphere-forming capacity, suggesting their potential xenograft origin. Cell cultures and xenografts retained the genomic alterations present in the parental tumor. Compared to VSCC, differentially expressed transcripts detected in all experimental conditions were associated with cellular morphology, movement, and metabolism and organization pathways. Malignant cell cultures and xenografts derived from a verrucous penile carcinoma were established and fully characterized. Nevertheless, xenograft PeCa models must be used with caution, taking into consideration the selection of specific cell populations and anatomical sites for cell/tumor implantation.

Mg(II)-Catechin nanoparticles delivering siRNA targeting EIF5A2 inhibit bladder cancer cell growth in vitro and in vivo

Emerging evidence indicates that combination of two or more therapeutic strategies can synergistically enhance antitumor activity in cancer therapy. Here, we established a green method of generating nanocomposite particles that can be fabricated using catechin, a natural anti-cancer compound from green tea, and Mg(2+) in an easy one-step approach at room temperature. We show that Mg(II)-Catechin nanocomposite particles (Mg(II)-Cat NPs) have good biocompatibility and high cellular uptake also can load and effectively deliver small interfering RNA (siRNA) into cells in vitro and to tumor site in vivo. Mg(II)-Cat NPs by themselves had tumor-suppression effects. When complexed with siRNA that targets oncogene eukaryotic translation initiation factor 5A2 (EIF5A2), Mg(II)-Cat/siEIF5A2 complex had further enhanced anti-tumor activity. Mechanistically, we show that Mg(II)-Cat/siEIF5A2 inhibits oncogenic PI3K/Akt signal pathway. More importantly, Mg(II)-Cat/siEIF5A2 had tumor suppression effect in a clinically-relevant rat in-situ bladder cancer model. Our studies demonstrated that combination of Mg(II)-Cat NPs and siRNA is a promising therapeutic modality of combining chemotherapy with gene therapy in order to afford higher therapeutic efficacy and provided a proof of principle for such modality in a pre-clinical setting.

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.

Key signaling pathways in the muscle-invasive bladder carcinoma: Clinical markers for disease modeling and optimized treatment

In this review, we evaluate key molecular pathways and markers of muscle-invasive bladder cancer (MIBC). Overexpression and activation of EGFR, p63, and EMT genes are suggestive of basal MIBC subtype generally responsive to chemotherapy. Alterations in PPARγ, ERBB2/3, and FGFR3 gene products and their signaling along with deregulated p53, cytokeratins KRT5/6/14 in combination with the cellular proliferation (Ki-67), and cell cycle markers (p16) indicate the need for more radical treatment protocols. Similarly, the "bell-shape" dynamics of Shh expression levels may suggest aggressive MIBC. A panel of diverse biological markers may be suitable for simulation studies of MIBC and development of an optimized treatment protocol. We conducted a critical evaluation of PubMed/Medline and SciFinder databases related to MIBC covering the period 2009-2015. The free-text search was extended by adding the following keywords and phrases: bladder cancer, metastatic, muscle-invasive, basal, luminal, epithelial-to-mesenchymal transition, cancer stem cell, mutations, immune response, signaling, biological markers, molecular markers, mathematical models, simulation, epigenetics, transmembrane, transcription factor, kinase, predictor, prognosis. The resulting selection of ca 500 abstracts was further analyzed in order to select the latest publications relevant to MIBC molecular markers of immediate clinical significance.

Eukaryotic translation initiation factor 5A2 (eIF5A2) regulates chemoresistance in colorectal cancer through epithelial mesenchymal transition

BACKGROUND

Chemoresistance is a major obstacle to successful chemotherapy for colorectal cancer. Eukaryotic translation initiation factor 5A2 (eIF5A2), one of the two isoforms in the eIF5A family, has been reported to be a new oncogene in many types of human cancer. In the present study, we aimed to investigate whether eIF5A2 was involved in the chemoresistance to doxorubicin in colorectal cancer.

METHODS

Cell viability was measured by CCK-8 assay with or without doxorubicin treatment. Protein expression was detected by western blot. Tumor cells were transfected with eIF5A2 siRNA or plasmid encoding eIF5A2 to down- or up regulate the expression of eIF5A2.

RESULTS

We found that eIF5A2-negtive colon cancer cells (HCT116 and HT29) were more sensitive to doxorubicin compare with the eIF5A2-positive cells (LOVO and SW480). Downregulation of eIF5A2 in LOVO and SW480 cells enhanced the chemosensitivity to doxorubicin. On the contrary, overexpression of eIF5A2 reduced doxorubicin sensitivity in colon cancer cells. In addition, eIF5A2 knockdown increased the protein level of E-cadherin and reduced vimentin expression in LOVO and SW480 cells. Meanwhile, upregulation of eIF5A2 potentiated epithelial mesenchymal transition (EMT) in colon cancer cells. Moreover, blockade of EMT with Twist siRNA abolished eIF5A2-regulated chemoresistance in colon cancer cells.

CONCLUSION

Our present study demonstrated that eIF5A2 promoted the chemoresistance to doxorubicin via regulation of EMT in colon cancer cells. Therefore, eIF5A2 inhibition may be a new potential strategy for the reversal of drug resistance in colorectal cancer therapy.

Sonic Hedgehog-GLI Family Zinc Finger 1 Signaling Pathway Promotes the Growth and Migration of Pancreatic Cancer Cells by Regulating the Transcription of Eukaryotic Translation Initiation Factor 5A2

OBJECTIVES

The Hh (hedgehog) signaling pathway is still waiting for further studies because its downstream molecular mechanism remains elusive. Because EIF5A2 (eukaryotic translation initiation factor 5A2) gene was up-regulated upon Gli1 (GLI family zinc finger 1) in pancreatic cancer (PC) cells, we speculated that this pathway might promote tumor progression through regulating EIF5A2.

METHODS

We investigated regulation effect of Hh signaling pathway to EIF5A2 gene transcription by Gli1 knockdown or overexpression in PC cell lines first. Then, the regulation mechanism of Gli1 to EIF5A2 gene was studied at transcription level. Finally, we studied cancer-promoting effects of Gli1-dependent EIF5A2 in PC cells.

RESULTS

The data showed that Gli1 up-regulated expression of EIF5A2 by promoting transcription via cis-acting elements in PC cells. Moreover, vimentin gene was up-regulated significantly by sonic hedgehog (SHh)/Gli1 expression increasing, and E-cadherin was significantly reduced. The EIF5A2 knockdown partially reversed cell proliferation and migration induced by artificial SHh overexpression and inhibited epithelial mesenchymal transition process in PC cells with SHh overexpression (P < 0.05).

CONCLUSIONS

Our data establish a novel transcription mechanism of Gli1 to EIF5A2 gene in cis-regulatory manner in PC cells. Thus, EIF5A2 oncogene effect could be incorporated into cancer-promoting molecular network upon Hh signaling pathway.

Stemness and chemotherapeutic drug resistance induced by EIF5A2 overexpression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies of the digestive tract in East Asian countries. Multimodal therapies, including adjuvant chemotherapy and neo-adjuvant chemotherapy, have become more often used for patients with advanced ESCC. However, the chemotherapy effect is often limited by patients' drug resistance. This study demonstrated that EIF5A2 (eukaryotic translation initiation factor 5A2) overexpression induced stemness and chemoresistance in ESCC cells. We showed that EIF5A2 overexpression in ESCC cells resulted in increased chemoresistance to 5-fluorouracil (5-FU), docetaxel and taxol. In contrast, shRNAs suppressing eIF5A2 increased tumor sensitivity to these chemotherapeutic drugs. In addition, EIF5A2 overexpression was correlated with a poorer overall survival in patients with ESCC who underwent taxane-based chemotherapy after esophagectomy (P < 0.05). Based on these results, we suggest that EIF5A2 could be a predictive biomarker for selecting appropriate chemo-treatment for ESCC patients and EIF5A2 inhibitors might be considered as combination therapy to enhance chemosensitivity in patients with ESCC.

Evaluation of Su Fu'ning Lotion's Inhibitory Effects on Bladder Cancer Cells In Vitro and In Vivo by Intravesical Instillation

BACKGROUND

Bladder cancer is a common malignant tumor with a very high recurrence rate after surgery. Intravesical instillation can help clear up the residual tumor cells after surgery and thereby reduce the recurrence rate.

OBJECTIVE

To establish a bladder tumor transplantation animal model and to evaluate the inhibitory effects of a novel perfusate, Su Fu'ning Lotion (SFN), on bladder tumor.

METHODS

SFN was compared with several commonly used chemotherapy drugs, including mitomycin (MMC) and pirarubicin (THP) for anticancer effects on the bladder cancer cell lines T24, BTT, and BIU-87 and SFN half inhibitory concentrations (IC50) were determined after 48 hours of treatment. In addition, bladder cancer orthotopic transplantation tumor models were established in BALB/C nude mice and T739 mice, and SFN anticancer effects were assessed in vivo, with normal saline and MMC as negative and positive controls, respectively.

RESULTS

SFN, MMC, and THP were all lethal to bladder cancer cells, in vitro, with SFN and THP significantly superior to MMC. IC50 values for SFN were 13.22, 11.22, and 12.5 µg/mL on T24, BTT, and BIU-87 cells, respectively. In vivo, SFN significantly reduced the mouse bladder wet weight and prolonged the animal survival compared with controls (P < .05), suggesting that SFN significantly inhibited T24/BTT cell growth in mice.

CONCLUSION

SFN inhibited the bladder cancer cell proliferation in vitro and in vivo and significantly prolonged the survival of mice with bladder cancer xenografts, indicating that SFN could be used as a perfusate after surgery for removal of residual bladder cancers cells.

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.