Gene Summary

Gene:EIF3E; eukaryotic translation initiation factor 3 subunit E
Aliases: INT6, EIF3S6, EIF3-P48, eIF3-p46
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:eukaryotic translation initiation factor 3 subunit E
Source:NCBIAccessed: 15 March, 2017


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: EIF3E (cancer-related)

Senfter D, Madlener S, Krupitza G, Mader RM
The microRNA-200 family: still much to discover.
Biomol Concepts. 2016; 7(5-6):311-319 [PubMed] Related Publications
In the last decade, microRNAs (miRs or miRNAs) became of great interest in cancer research due to their multifunctional and active regulation in a variety of vital cellular processes. In this review, we discuss the miR-200 family, which is composed of five members (miR-141, miR-200a/200b/200c and miR-429). Although being among the best investigated miRNAs in the field, there are still many open issues. Here, we describe the potential role of miR-200 as prognostic and/or predictive biomarker, its influence on motility and cell migration as well as its role in epithelial to mesenchymal transition (EMT) and metastasis formation in different tumour types. Recent studies also demonstrated the influence of miR-200 on drug resistance and described a correlation between miR-200 expression levels and overall survival of patients. Despite intense research in this field, the full role of the miR-200 family in cancer progression and metastasis is not completely understood and seems to differ between different tumour types and different cellular backgrounds. To elucidate these differences further, a finer characterisation of the role of the individual miRNA-200 family members is currently under investigation.

Wang M, Xiao X, Zeng F, et al.
Common and differentially expressed long noncoding RNAs for the characterization of high and low grade bladder cancer.
Gene. 2016; 592(1):78-85 [PubMed] Related Publications
Our study aimed to explore long non-coding RNAs (lncRNAs) contributing to the development of bladder cancer, as well as to identify more critical DEGs and lncRNAs that would characterize low- and high-grade bladder cancer. The microarray data of GSE55433 was downloaded from Gene Expression Omnibus database, including 57 urothelial cancer samples (23 low-grade NMI, 14 high-grade NMI and 20 invasive tumors) and 26 normal controls. The differentially expressed genes (DEGs) and differentially expressed lncRNAs were identified in 3 groups (low-grade NMI vs. normal, high-grade NMI vs. normal and invasive UC vs. normal). Functional enrichment analysis was performed upon the DEGs in different groups. Besides, protein-protein interaction (PPI) network was constructed based on common DEGs and remaining DEGs in each group. Co-expression analysis was performed to identify the co-expressed DEG-lncRNAs pairs. Different number of DEGs and differentially expressed lncRNAs were respectively identified from those 3 groups. NONHSAG013805 (down-regulated) and NONHSAG009271 (down-regulated) were common lncRNAs. NONHSAG013805 was connected with the down-regulated gene EIF3E and NONHSAG009271 was linked to MYL12A (down-regulated). Moreover, NONHSAG034203 (up-regulated) was co-expressed with ADM5 (up-regulated) in low-grade NMI cancer, while the down-regulated NONHSAG045391 was connected with the down-regulated DEGs DAD1 and STUB1 in high-grade NMI cancer and invasive bladder cancer. Our study indicates that NONHSAG013805 and NONHSAG009271 may play key roles in bladder cancer via co-expressing with EIF3E and MYL12A, respectively. Moreover, NONHSAG034203 may be involved in low-grade NMI bladder cancer via targeting ADM5, while NONHSAG045391 may contribute to high-grade NMI and invasive bladder cancer via targeting DAD1 and STUB1.

Pan XW, Chen L, Hong Y, et al.
EIF3D silencing suppresses renal cell carcinoma tumorigenesis via inducing G2/M arrest through downregulation of Cyclin B1/CDK1 signaling.
Int J Oncol. 2016; 48(6):2580-90 [PubMed] Related Publications
There are no effective therapies for advanced renal cell carcinoma (RCC), except for VEGFR inhibitors with only ~50% response rate. To identify novel targets and biomarkers for RCC is of great importance in treating RCC. In this study, we observed that eukaryotic initiation factor 3d (EIF3D) expression was significantly increased in RCC compared with paracarcinoma tissue using immunohistochemistry staining and western blot analysis. Furthermore, bioinformatics meta-analysis using ONCOMINE microarray datasets showed that EIF3D mRNA expressions in CCRCC tissue specimens were significantly higher than that in normal tissue specimens. In addition, RCC tissue microarray demonstrated that elevated EIF3D expression was positively correlated with TNM stage and tumor size. EIF3D silencing in human 786-O and ACHN CCRCC cell lines by RNA interference demonstrated that EIF3D knockdown obviously inhibited cell proliferation and colony formation, caused G2/M arrest through downregulation of Cyclin B1 and Cdk1 and upregulation of p21, and induced apoptosis shown by sub-G1 accumulation and RARP cleavage. Moreover, correlation analysis using ONCOMINE microarray datasets indicated that increased EIF3D mRNA expression was positively correlated to PCNA, Cyclin B1 and CDK1 mRNA expression in RCC. Collectively, these results provide reasonable evidences that EIF3D may function as a potential proto-oncogene that participates in the occurrence and progression of RCC.

Lee JY, Kim HJ, Rho SB, Lee SH
eIF3f reduces tumor growth by directly interrupting clusterin with anti-apoptotic property in cancer cells.
Oncotarget. 2016; 7(14):18541-57 [PubMed] Free Access to Full Article Related Publications
Clusterin is a secretory heterodimeric glycoprotein and the overexpression of secretory clusterin (sCLU) promotes cancer cell proliferation and reduces chemosensitivity. Therefore, sCLU might be an effective target for anticancer therapy. In the current study, we identified eIF3f as a novel CLU-interacting protein and demonstrated its novel function as a CLU inhibitor. The overexpression of eIF3f retarded cancer cell growth significantly and induced apoptosis. In addition, eIF3f interacted with the α-chain (1-227) of sCLU. This interaction blocked modification of psCLU, thereby decreasing the expression and secretion of α/β CLU. Consequently, the overexpression of eIF3f suppressed Akt and ERK signaling and subsequently depleted CLU expression. In addition, eIF3F stabilized p53, which increased the expression of p21 and Bax. Interestingly, the expression of Bax was increased without the activation of p53. eIF3f injected into a xenograft model of human cervical cancer in nude mice markedly inhibited tumor growth. The identification of this novel function of eIF3f as a sCLU inhibitor might open novel avenues for developing improved strategies for CLU-targeted anti-cancer therapies.

Zheng Q, Liu H, Ye J, et al.
Nuclear distribution of eIF3g and its interacting nuclear proteins in breast cancer cells.
Mol Med Rep. 2016; 13(4):2973-80 [PubMed] Free Access to Full Article Related Publications
Eukaryotic translation initiation factor 3 subunit g (eIF3g) is a core subunit of the eukaryotic translation initiation factor 3 complex, and is important in the initiation of translation. It is also involved in caspase-mediated apoptosis, and is upregulated in multidrug-resistant cancer cells. In the present study, the nuclear distribution of eIF3g was determined by performing co-immunoprecipitation of proteins that potentially interact with eIF3g in the nucleus. Mass spectrometry characterization showed that three proteins, heterogeneous nuclear ribonucleoprotein U/scaffold attachment factor A, HSZFP36/zinc finger protein 823 and β‑actin, were among the candidate eIF3g‑interacting proteins in the nucleus. The protein‑protein interaction was further confirmed by cross‑linking and a glutathione S‑transferase pull‑down assay, followed by western blotting. The co‑localization of these proteins was determined by confocal microscopy. These findings provide novel insight into the possible functions of eIF3g in the nucleus and serves as an important first step for further investigation of the roles of eIF3g in cancer development.

Fan Y, Guo Y
Knockdown of eIF3D inhibits breast cancer cell proliferation and invasion through suppressing the Wnt/β-catenin signaling pathway.
Int J Clin Exp Pathol. 2015; 8(9):10420-7 [PubMed] Free Access to Full Article Related Publications
eIF3D (eukaryotic translation initiation factor 3 subunit D) is one member of the eIF3 family and plays a critical role in translation initiation. Previous studies showed that it was involved in the development and progression of several tumors. However, the role of eIF3D in breast cancer and the underlying mechanism is still unclear. Therefore, this study set out to investigate the role of eIF3D in breast cancer. Our results demonstrated that eIF3D is up-regulated in breast cancer cells. Knockdown of eIF3D inhibited breast cancer cell proliferation and invasion. In addition, knockdown of eIF3D inhibited the expression of β-catenin, cyclin D1 and c-Myc in breast cancer cells. Taken together, our findings show that siRNA-eIF3D inhibits breast cancer cell proliferation and invasion through suppressing the Wnt/β-catenin signaling pathway. Therefore, eIF3D may be a good molecular target for the prevention and treatment of breast cancer.

Zhang Y, Yu JJ, Tian Y, et al.
eIF3a improve cisplatin sensitivity in ovarian cancer by regulating XPC and p27Kip1 translation.
Oncotarget. 2015; 6(28):25441-51 [PubMed] Free Access to Full Article Related Publications
The eukaryotic translation initiation factor 3a (eIF3a) is one of the core subunits of the translation initiation complex eIF3, responsible for ribosomal subunit joining and mRNA recruitment to the ribosome. Our previous study identified that it was correlated with platinum response in lung cancer. The current study aims to test the hypothesis that eIF3a may affect the drug response and prognosis of ovarian cancer patients receiving platinum-based chemotherapy by regulating xeroderma pigmentosum complementation group C (XPC) and p27(Kip1). Immunohistochemistry and western blot was used to determine the expression of eIF3a in 126 human ovarian cancer tissues followed by association analysis of eIF3a expression with patient's response and survival. Ectopic over-expression and RNA interference knockdown of eIF3a were carried out in A2780/cisplatin (DDP) and its parental A2780 cells, respectively, to determine the effect of altered eIF3a expression on cellular response to cisplatin by employing MTT assay. Western Blot analyses were also carried out to determine the regulation of eIF3a on XPC and p27(Kip1). eIF3a expression was associated with response of ovarian cancer patients to DDP-based chemotherapy and their survival. Overexpression and knockdown of eIF3a increased and decreased the cellular response to cisplatin in A2780/DDP and A2780 cells, respectively. In addition, XPC and p27(Kip1) were down regulated by eIF3a. eIF3a improves ovarian cancer patients' response to DDP-based chemotherapy via down regulating XPC and p27(Kip1).

Schipany K, Rosner M, Ionce L, et al.
eIF3 controls cell size independently of S6K1-activity.
Oncotarget. 2015; 6(27):24361-75 [PubMed] Free Access to Full Article Related Publications
All multicellular organisms require a life-long regulation of the number and the size of cells, which build up their organs. mTOR acts as a signaling nodule for the regulation of protein synthesis and growth. To activate the translational cascade, mTOR phosphorylates S6 kinase (S6K1), which is liberated from the eIF3-complex and mobilized for activation of its downstream targets. How S6K1 regulates cell size remains unclear. Here, we challenged cell size control through S6K1 by specifically depleting its binding partner eIF3 in normal and transformed cell lines. We show that loss of eIF3 leads to a massive reduction of cell size and cell number accompanied with an unexpected increase in S6K1-activity. The hyperactive S6K1-signaling was rapamycin-sensitive, suggesting an upstream mTOR-regulation. A selective S6K1 inhibitor (PF-4708671) was unable to interfere with the reduced size, despite efficiently inhibiting S6K1-activity. Restoration of eIF3 expression recovered size defects, without affecting the p-S6 levels. We further show that two, yet uncharacterized, cancer-associated mutations in the eIF3-complex, have the capacity to recover from reduced size phenotype, suggesting a possible role for eIF3 in regulating cancer cell size. Collectively, our results uncover a role for eIF3-complex in maintenance of normal and neoplastic cell size - independent of S6K1-signaling.

Gao Y, Teng J, Hong Y, et al.
The oncogenic role of EIF3D is associated with increased cell cycle progression and motility in prostate cancer.
Med Oncol. 2015; 32(7):518 [PubMed] Related Publications
EIF3 is the largest multi-protein complex, and several studies have revealed the oncogenic roles of its subunits in many human cancers. However, the roles of EIF3D in the development and progression of PCa remain uncovered. In the present study, the expression of EIF3D in prostate cancer and paracarcinoma tissues, as well as PCa cell lines, was examined. In PCa tissues, the expression of EIF3D was up-regulated compared to that in paracarcinoma tissues. In order to investigate whether EIF3D could serve as potential therapeutic target for prostate cancer, EIF3D was knocked down to verify its functional role in prostate cancer cells. After EIF3D knockdown in PC-3 and DU145 cells, cell proliferation, invasion and colony formation were significantly inhibited; meanwhile, cell cycle analysis revealed cell cycle arrest at G2/M phase. EIF3D is associated with PCa, and silencing EIF3D will result in decreased proliferation, and migration, as well as G2/M arrest in DU145 and PC-3 cells. These results suggest that EIF3D plays an oncogenic role in PCa development and progression.

Lee AS, Kranzusch PJ, Cate JH
eIF3 targets cell-proliferation messenger RNAs for translational activation or repression.
Nature. 2015; 522(7554):111-4 [PubMed] Free Access to Full Article Related Publications
Regulation of protein synthesis is fundamental for all aspects of eukaryotic biology by controlling development, homeostasis and stress responses. The 13-subunit, 800-kilodalton eukaryotic initiation factor 3 (eIF3) organizes initiation factor and ribosome interactions required for productive translation. However, current understanding of eIF3 function does not explain genetic evidence correlating eIF3 deregulation with tissue-specific cancers and developmental defects. Here we report the genome-wide discovery of human transcripts that interact with eIF3 using photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP). eIF3 binds to a highly specific program of messenger RNAs involved in cell growth control processes, including cell cycling, differentiation and apoptosis, via the mRNA 5' untranslated region. Surprisingly, functional analysis of the interaction between eIF3 and two mRNAs encoding the cell proliferation regulators c-JUN and BTG1 reveals that eIF3 uses different modes of RNA stem-loop binding to exert either translational activation or repression. Our findings illuminate a new role for eIF3 in governing a specialized repertoire of gene expression and suggest that binding of eIF3 to specific mRNAs could be targeted to control carcinogenesis.

Hao J, Wang Z, Wang Y, et al.
Eukaryotic initiation factor 3C silencing inhibits cell proliferation and promotes apoptosis in human glioma.
Oncol Rep. 2015; 33(6):2954-62 [PubMed] Related Publications
Eukaryotic initiation factor 3, subunit c (eIF3c), an oncogene overexpressed in human cancers, plays an important role in cell tumorigenesis and proliferation. However, studies assessing its function in gliomas are scarce. The present study evaluated for the first time, the role of eIF3c in gliomas. Immunohistochemistry was carried out to assess eIF3c expression in 95 human glioma samples and normal brain tissues. Then, the eIF3c mRNA levels were detected in tumor and normal brain specimens by quantitative RT-PCR. In addition, eIF3c mRNA levels were assessed in four glioma cell lines (U87, U251, A172 and U373) by semi-quantitative RT-PCR. The RNA interference (RNAi) technology was employed to knock down the eIF3c gene in the U251 cells. Western blot analysis, BrdU assay and flow cytometry were used to measure eIF3c protein levels, cell proliferation, cell apoptosis and cell cycle, respectively. The eIF3c protein was overexpressed in the human glioma specimens. In agreement, the eIF3c mRNA expression levels were significantly higher in the human glioma tissues compared with the normal brain samples (P<0.0001). In addition, eIF3c mRNA was detected in all the glioma cell lines. Silencing the eIF3c gene in the U251 cells by RNAi significantly suppressed cell proliferation (P<0.01) and increased apoptosis (P<0.01). Finally, a stark decrease was observed in the G1 phase cell number (P<0.01), while the S and G2 phase cells were significantly increased (P<0.01) after eIF3c knockdown. These findings suggest that eIF3c is overexpressed in human gliomas and essential for their proliferation and survival. Therefore, inhibiting eIF3c expression may constitute an effective therapy for human glioma.

Yin JY, Meng XG, Qian CY, et al.
Association of positively selected eIF3a polymorphisms with toxicity of platinum-based chemotherapy in NSCLC patients.
Acta Pharmacol Sin. 2015; 36(3):375-84 [PubMed] Free Access to Full Article Related Publications
AIM: Eukaryotic translation initiation factor 3 subunit A (eIF3a) plays critical roles in regulating the initiation of protein translation, and eIF3a is highly expressed in lung cancer. In this study, we investigated the association of the positively selected SNPs of eIF3a with the response to and toxicity of platinum-based chemotherapy in Chinese patients with non-small cell lung cancer (NSCLC).
METHODS: SNP data for eIF3a locus were downloaded from HapMap database. For each SNP, haplotype, LD profile and population differentiation were analyzed. The long-range haplotype (LRH) test was employed to identify positively selected SNPs of eIF3a. A total of 325 NSCLC patients were enrolled and genotyped for these SNPs.
RESULTS: Five positively selected (rs1409314, rs4752219, rs4752220, rs7091672 and rs10510050) and 5 non-positively selected SNPs (rs10886342, rs11198804, rs2275112, rs10787899 and rs4752269) were identified in the LRH test. However, none of them was correlated with the platinum-based chemotherapy response. In contrast, 4 of the positively selected SNPs (rs1409314, rs4752219, rs4752220 and rs7091672) were significantly correlated with the toxicities tested (neutropenia, anemia, thrombocytopenia, emesis and hepatotoxicity). In addition, rs10510050 was significantly correlated with thrombocytopenia, emesis and hepatotoxicity. None of the 5 non-positively selected SNPs was correlated with the 5 toxicities.
CONCLUSION: The positively selected SNPs of eIF3a are significantly correlated with platinum-based chemotherapy toxicities in Chinese NSCLC patients.

Ren M, Zhou C, Liang H, et al.
RNAi-Mediated Silencing of EIF3D Alleviates Proliferation and Migration of Glioma U251 and U87MG Cells.
Chem Biol Drug Des. 2015; 86(4):715-22 [PubMed] Related Publications
As the most common primary malignant brain tumors, gliomas cause more years of life lost than do any other tumors. Recently, abnormalities of the eukaryotic initiation factors (EIFs) have been reported in gliomas. Yet the role of EIF3D, which encodes a subunit of EIF3 multiprotein complex, remains poorly understood. In this study, we found EIF3D expression was positively correlated with WHO grades of gliomas. Furthermore, we employ lentivirus-mediated RNA interference (RNAi) to examine the physiological role of EIF3D in glioma cells. Decreased EIF3D expression in U251 and U87MG glioma cells caused a delay in cell growth and a disruption in colony formation. In addition, EIF3D knockdown induced G0/G1 phase cell cycle arrest and apoptosis. Cells with suppressed expression of EIF3D had a lower capacity to migrate in the transwell assay. These results suggest that EIF3D plays an important role in glioma development and may serve as a potential therapeutic target for human glioma.

Wang C, Jin G, Jin H, et al.
Clusterin facilitates metastasis by EIF3I/Akt/MMP13 signaling in hepatocellular carcinoma.
Oncotarget. 2015; 6(5):2903-16 [PubMed] Free Access to Full Article Related Publications
Clusterin (CLU) is a stress-induced chaperone that confers proliferative and survival advantages to cancer cells. However, effects and molecular mechanisms of CLU in hepatocellular carcinoma (HCC) metastasis are still unknown. In this study, HCC tissue array (n = 198) was utilized to investigate correlation between CLU expression and clinicopathological features. Overexpression of CLU in HCC tissues was correlated with shorter overall survival and higher tumor recurrence. In vitro and in vivo assays demonstrated that silencing CLU attenuated the invasion and metastasis of HCC cells, whereas ectopic overexpression of CLU resulted in the forced metastasis of HCC cells. We also revealed that CLU activated Akt signaling through complexing with eukaryotic translation initiation factor 3 subunit I (EIF3I), which in turn promoted matrix metalloproteinase 13 (MMP13) expression and HCC metastasis. Positive correlations between CLU and MMP13, p-Akt, or EIF3I were found in HCC tissues. We further observed that CLU knockdown using the CLU inhibitor OGX-011 significantly suppressed HCC metastasis in two metastatic models through inhibiting EIF3I/Akt/MMP13 signaling. These findings indicate that CLU is an independent predictive factor for prognosis of HCC and it facilitates metastasis through EIF3I/Akt/MMP13 signaling. CLU suppression using OGX-011 may represent a promising therapeutic option for suppressing HCC metastasis.

Gong X, Yi J, Carmon KS, et al.
Aberrant RSPO3-LGR4 signaling in Keap1-deficient lung adenocarcinomas promotes tumor aggressiveness.
Oncogene. 2015; 34(36):4692-701 [PubMed] Free Access to Full Article Related Publications
The four R-spondins (RSPO1-4) and their three related receptors LGR4, 5 and 6 (LGR4-6) have emerged as a major ligand-receptor system with critical roles in development and stem cell survival through modulation of Wnt signaling. Recurrent, gain-of-expression gene fusions of RSPO2 (to EIF3E) and RSPO3 (to PTPRK) occur in a subset of human colorectal cancer. However, the exact roles and mechanisms of the RSPO-LGR system in oncogenesis remain largely unknown. We found that RSPO3 is aberrantly expressed at high levels in approximately half of Keap1-mutated lung adenocarcinomas (ADs). This high RSPO3 expression is driven by a combination of demethylation of its own promoter region and deficiency in Keap1 instead of gene fusion as in colon cancer. Patients with RSPO3-high tumors (~9%, 36/412) displayed much poorer survival than the rest of the cohort (median survival of 28 vs 163 months, log-rank test P<0.0001). Knockdown (KD) of RSPO3, LGR4 or their signaling mediator IQGAP1 in lung cancer cell lines with Keap1 deficiency and high RSPO3-LGR4 expression led to reduction in cell proliferation and migration in vitro, and KD of LGR4 or IQGAP1 resulted in decrease in tumor growth and metastasis in vivo. These findings suggest that aberrant RSPO3-LGR4 signaling potentially acts as a driving mechanism in the aggressiveness of Keap1-deficient lung ADs.

Yu X, Zheng B, Chai R
Lentivirus-mediated knockdown of eukaryotic translation initiation factor 3 subunit D inhibits proliferation of HCT116 colon cancer cells.
Biosci Rep. 2014; 34(6):e00161 [PubMed] Free Access to Full Article Related Publications
Dysregulation of protein synthesis is emerging as a major contributory factor in cancer development. eIF3D (eukaryotic translation initiation factor 3 subunit D) is one member of the eIF3 (eukaryotic translation initiation factor 3) family, which is essential for initiation of protein synthesis in eukaryotic cells. Acquaintance with eIF3D is little since it has been identified as a dispensable subunit of eIF3 complex. Recently, eIF3D was found to embed somatic mutations in human colorectal cancers, indicating its importance for tumour progression. To further probe into its action in colon cancer, we utilized lentivirus-mediated RNA interference to knock down eIF3D expression in one colon cancer cell line HCT116. Knockdown of eIF3D in HCT116 cells significantly inhibited cell proliferation and colony formation in vitro. Flow cytometry analysis indicated that depletion of eIF3D led to cell-cycle arrest in the G2/M phase, and induced an excess accumulation of HCT116 cells in the sub-G1 phase representing apoptotic cells. Signalling pathways responsible for cell growth and apoptosis have also been found altered after eIF3D silencing, such as AMPKα (AMP-activated protein kinase alpha), Bad, PRAS40 [proline-rich Akt (PKB) substrate of 40 kDa], SAPK (stress-activated protein kinase)/JNK (c-Jun N-terminal kinase), GSK3β and PARP [poly(ADP-ribose) polymerase]. Taken together, these findings suggest that eIF3D might play an important role in colon cancer progression.

Li H, Zhou F, Wang H, et al.
Knockdown of EIF3D suppresses proliferation of human melanoma cells through G2/M phase arrest.
Biotechnol Appl Biochem. 2015 Sep-Oct; 62(5):615-20 [PubMed] Related Publications
Skin cancer is the most common malignancy with increasing incidence rates worldwide. The advanced form of skin cancer, melanoma, is resistant to conventional treatment methods, which motivated researchers to identify an alternative effective therapeutic approach. This study was designed to identify the effects of small interfering RNA (si-RNA) mediated silencing of eukaryotic translation initiation factor 3, subunit D (EIF3D) against melanoma cell survival. Briefly, a lentivirus-mediated RNA interference system was employed to knock down EIF3D expression in A375 and A431 melanoma cells. The cell proliferation was analyzed by methylthiazoletetrazolium (MTT) and colony formation assays. The cell cycle progression was investigated using flow cytometry. Results revealed that si-RNA-mediated knockdown of EIF3D significantly reduced the gene and protein expression levels of EIF3D in melanoma cells. Furthermore, knockdown of EIF3D led to a significant reduction in cell proliferation due to G2 /M phase cell cycle arrest. Apparently, the study demonstrated the critical involvement of EIF3D in the survival and progression of melanoma cells and depletion of EIF3D could be developed as a possible therapeutic option in the gene-targeted treatment of melanoma.

Hutt DM, Roth DM, Vignaud H, et al.
The histone deacetylase inhibitor, Vorinostat, represses hypoxia inducible factor 1 alpha expression through translational inhibition.
PLoS One. 2014; 9(8):e106224 [PubMed] Free Access to Full Article Related Publications
Hypoxia inducible factor 1α (HIF-1α) is a master regulator of tumor angiogenesis being one of the major targets for cancer therapy. Previous studies have shown that Histone Deacetylase Inhibitors (HDACi) block tumor angiogenesis through the inhibition of HIF-1α expression. As such, Vorinostat (Suberoylanilide Hydroxamic Acid/SAHA) and Romidepsin, two HDACis, were recently approved by the Food and Drug Administration (FDA) for the treatment of cutaneous T cell lymphoma. Although HDACis have been shown to affect HIF-1α expression by modulating its interactions with the Hsp70/Hsp90 chaperone axis or its acetylation status, the molecular mechanisms by which HDACis inhibit HIF-1α expression need to be further characterized. Here, we report that the FDA-approved HDACi Vorinostat/SAHA inhibits HIF-1α expression in liver cancer-derived cell lines, by a new mechanism independent of p53, prolyl-hydroxylases, autophagy and proteasome degradation. We found that SAHA or silencing of HDAC9 mechanism of action is due to inhibition of HIF-1α translation, which in turn, is mediated by the eukaryotic translation initiation factor--eIF3G. We also highlighted that HIF-1α translation is dramatically inhibited when SAHA is combined with eIF3H silencing. Taken together, we show that HDAC activity regulates HIF-1α translation, with HDACis such as SAHA representing a potential novel approach for the treatment of hepatocellular carcinoma.

Yuan Y, Zhang Y, Yao S, et al.
The translation initiation factor eIF3i up-regulates vascular endothelial growth factor A, accelerates cell proliferation, and promotes angiogenesis in embryonic development and tumorigenesis.
J Biol Chem. 2014; 289(41):28310-23 [PubMed] Free Access to Full Article Related Publications
Vascular endothelial growth factor A (VEGFA) is a critical proangiogenic factor that is activated by hypoxia at both the transcriptional and post-transcriptional levels. In hypoxia conditions, stabilized hypoxia-inducible factor 1α (HIF1A) is the key regulator for transcriptional activation of VEGFA. However, the post-transcriptional control of VEGFA expression remains poorly understood. Here, we report that the eukaryotic translation initiation factor 3i (eIF3i) is required for VEGFA protein expression in both normal embryonic and tumorigenic angiogenesis. eIF3i is dynamically expressed in the early stages of zebrafish embryogenesis and in human hepatocellular carcinoma tissues. eIF3i homozygous mutant zebrafish embryos show severe angiogenesis defects and human hepatocellular cancer cells with depletion of eIF3i to induce less angiogenesis in tumor models. Under hypoxia, the HIF1A protein can interact with its binding sequence in the eIF3i promoter and activate eIF3i transcription. The expression of VEGFA, which should rise in hypoxia, is significantly inhibited by eIF3i siRNA treatment. Moreover, eIF3i knockdown did not cause a general translation repression but specifically reduced the translation efficiency of the VEGFA mRNAs. Taken together, our results suggest that eIF3i is induced by HIF1A under hypoxia and controls normal and tumorigenic angiogenesis through regulating VEGFA protein translation.

Lin VC, Kuo PT, Lin YC, et al.
Penta-O-galloyl-β-D-glucose suppresses EGF-induced eIF3i expression through inhibition of the PI3K/AKT/mTOR pathway in prostate cancer cells.
J Agric Food Chem. 2014; 62(36):8990-6 [PubMed] Related Publications
Approximately 70% of prostate cancer patients will develop bone metastasis in axial and other regions of the skeleton. Epidermal growth factor (EGF) generated from bone tissue contributes to prostate cancer metastasis. In a previous study, penta-O-galloyl-β-D-glucose (PGG) suppressed androgen-independent prostate cancer bone metastasis by transcriptionally repressing EGF-induced MMP-9 expression. This study utilized proteomics to analyze the effects of PGG in EGF-induced prostate cancer bone metastasis. This study showed that PGG suppressed EGF-induced eIF3i expression in PC-3 cells. By transfection of eIF3i shRNA, it was observed that reduced eIF3i expression suppressed the invasion of PC-3 cells in vitro. PGG reduced EGF-induced eIF3i expression through inhibition of the PI3K/AKT/mTOR pathway. Therefore, PGG may be able to be used as a potential new therapeutic drug for prostate cancer bone metastasis.

Yong ZW, Zaini ZM, Kallarakkal TG, et al.
Genetic alterations of chromosome 8 genes in oral cancer.
Sci Rep. 2014; 4:6073 [PubMed] Free Access to Full Article Related Publications
The clinical relevance of DNA copy number alterations in chromosome 8 were investigated in oral cancers. The copy numbers of 30 selected genes in 33 OSCC patients were detected using the multiplex ligation-dependent probe amplification (MLPA) technique. Amplifications of the EIF3E gene were found in 27.3% of the patients, MYC in 18.2%, RECQL4 in 15.2% and MYBL1 in 12.1% of patients. The most frequent gene losses found were the GATA4 gene (24.2%), FGFR1 gene (24.2%), MSRA (21.2) and CSGALNACT1 (12.1%). The co-amplification of EIF3E and RECQL4 was found in 9% of patients and showed significant association with alcohol drinkers. There was a significant association between the amplification of EIF3E gene with non-betel quid chewers and the negative lymph node status. EIF3E amplifications did not show prognostic significance on survival. Our results suggest that EIF3E may have a role in the carcinogenesis of OSCC in non-betel quid chewers.

Spilka R, Ernst C, Bergler H, et al.
eIF3a is over-expressed in urinary bladder cancer and influences its phenotype independent of translation initiation.
Cell Oncol (Dordr). 2014; 37(4):253-67 [PubMed] Related Publications
PURPOSE: The eukaryotic translation initiation factor (eIF) 3a, the largest subunit of the eIF3 complex, is a key functional entity in ribosome establishment and translation initiation. In the past, aberrant eIF3a expression has been linked to the pathology of various cancer types but, so far, its expression has not been investigated in transitional cell carcinomas. Here, we investigated the impact of eIF3 expression on urinary bladder cancer (UBC) cell characteristics and UBC patient survival.
METHODS AND RESULTS: eIF3a expression was reduced through inducible knockdown in the UBC-derived cell lines RT112, T24, 5637 and HT1197. As a consequence of eIF3a down-regulation, UBC cell proliferation, clonogenic potential and motility were found to be decreased and, concordantly, UBC tumour cell growth rates were found to be impaired in xenotransplanted mice. Polysomal profiling revealed that reduced eIF3a levels increased the abundance of 80S ribosomes, rather than impairing translation initiation. Microarray-based gene expression and ontology analyses revealed broad effects of eIF3a knockdown on the transcriptome. Analysis of eIF3a expression in primary formalin-fixed paraffin embedded UBC samples of 198 patients revealed that eIF3a up-regulation corresponds to tumour grade and that high eIF3a expression corresponds to longer overall survival rates of patients with low grade tumours.
CONCLUSIONS: From our results we conclude that eIF3a expression may have a profound effect on the UBC phenotype and, in addition, may serve as a prognostic marker for low grade UBCs.

Shinmura K, Kahyo T, Kato H, et al.
RSPO fusion transcripts in colorectal cancer in Japanese population.
Mol Biol Rep. 2014; 41(8):5375-84 [PubMed] Related Publications
R-spondin (RSPO) gene fusions have recently been discovered in a subset of human colorectal cancer (CRC) in the U.S. population; however, whether the fusion is recurrent in CRC arising in patients from the other demographic areas and whether it is specific for CRC remain uncertain. In this study, we examined 75 primary CRCs and 121 primary lung cancers in the Japanese population for EIF3E-RSPO2 and PTPRK-RSPO3 fusion transcripts using RT-PCR and subsequent sequencing analyses. Although the expression of EIF3E-RSPO2 and PTPRK-RSPO3 was not detected in any of the lung carcinomas, RSPO fusions were detected in three (4%) of the 75 CRCs. Two CRCs contained EIF3E-RSPO2 fusion transcripts, and another CRC contained PTPRK-RSPO3 fusion transcripts. Interestingly, in one of the two EIF3E-RSPO2 fusion-positive CRCs, a novel fusion variant form of EIF3E-RSPO2 was identified: exon 1 of EIF3E was connected to exon 2 of RSPO2 by a 351-bp insertion. A quantitative RT-PCR analysis revealed that RSPO mRNA expression was upregulated in the three CRCs containing RSPO fusion transcripts, while it was downregulated in nearly all of the other CRCs. An immunohistochemical analysis and a mutational analysis revealed that the RSPO fusion-containing CRC had a CDX2 cell lineage, was positive for mismatch repair protein expression, and had the wild-type APC allele. Finally, the forced expression of RSPO fusion proteins were shown to endow colorectal cells with an increased growth ability. These results suggest that the expression of RSPO fusion transcripts is related to a subset of CRCs arising in the Japanese population.

Lei Z, Xu G, Wang L, et al.
MiR-142-3p represses TGF-β-induced growth inhibition through repression of TGFβR1 in non-small cell lung cancer.
FASEB J. 2014; 28(6):2696-704 [PubMed] Related Publications
TGFβR1 plays an important role in TGF-β signaling transduction and serves as a tumor suppressor. Our previous studies show that reduced expression of TGFβR1 is common in non-small cell lung cancer (NSCLC) and TGFβR1 variants confer risk of NSCLC. However, the epigenetic mechanisms underlying the role of TGFβR1 in NSCLC carcinogenesis are still elusive. We investigated the function and regulation of TGF-β signaling-based miRNAs in NSCLC. Computational algorithms predicted that the 3'-untranslated region (3'-UTR) of TGFβR1 is a target of miR-142-3p. Here a luciferase reporter assay confirmed that miR-142-3p can directly bind to 3'-UTR of TGFβR1. Overexpression of miR-142-3p in NSCLC A549 cells suppressed expression of TGFβR1 mRNA and protein, while knockdown of endogenous miR-142-3p led to increased expression of TGFβR1. On TGF-β1 stimulation, stable overexpression of miR-142-3p attenuated phosphorylation of SMAD3, an indispensable downstream effector in canonical TGF-β/Smad signaling, via repression of TGFβR1 in A549 cells. Furthermore, miR-142-3p-mediated down-regulation of TGFβR1 weakened TGF-β-induced growth inhibition effect, and this effect was reversed by stable knockdown of endogenous miR-142-3p in A549 cells. In NSCLC tissues, miR-142-3p expression was increased and inversely correlated with TGFβR1 expression. These data demonstrate that miR-142-3p influences the proliferation of NSCLC cells through repression of TGFβR1.

Sesen J, Cammas A, Scotland SJ, et al.
Int6/eIF3e is essential for proliferation and survival of human glioblastoma cells.
Int J Mol Sci. 2014; 15(2):2172-90 [PubMed] Free Access to Full Article Related Publications
Glioblastomas (GBM) are very aggressive and malignant brain tumors, with frequent relapses despite an appropriate treatment combining surgery, chemotherapy and radiotherapy. In GBM, hypoxia is a characteristic feature and activation of Hypoxia Inducible Factors (HIF-1α and HIF-2α) has been associated with resistance to anti-cancer therapeutics. Int6, also named eIF3e, is the "e" subunit of the translation initiation factor eIF3, and was identified as novel regulator of HIF-2α. Eukaryotic initiation factors (eIFs) are key factors regulating total protein synthesis, which controls cell growth, size and proliferation. The functional significance of Int6 and the effect of Int6/EIF3E gene silencing on human brain GBM has not yet been described and its role on the HIFs is unknown in glioma cells. In the present study, we show that Int6/eIF3e suppression affects cell proliferation, cell cycle and apoptosis of various GBM cells. We highlight that Int6 inhibition induces a diminution of proliferation through cell cycle arrest and increased apoptosis. Surprisingly, these phenotypes are independent of global cell translation inhibition and are accompanied by decreased HIF expression when Int6 is silenced. In conclusion, we demonstrate here that Int6/eIF3e is essential for proliferation and survival of GBM cells, presumably through modulation of the HIFs.

Magistri P, Leonard SY, Tang CM, et al.
The glypican 3 hepatocellular carcinoma marker regulates human hepatic stellate cells via Hedgehog signaling.
J Surg Res. 2014; 187(2):377-85 [PubMed] Related Publications
BACKGROUND: Hepatocellular carcinoma (HCC) frequently represents two diseases as it often arises in the setting of cirrhosis caused by the proliferation and activation of hepatic stellate cells (HSCs). Previously, we identified that Hedgehog (Hh) signaling regulates HSC viability and fibrinogenesis, as well as HCC tumorigenesis. Although it is increasingly recognized that HSCs and HCCs communicate via paracrine signaling, Hh's role in this process is just emerging. We hypothesized that a secreted HCC tumor marker and Hh mediator, glypican 3 (GPC3), may regulate HSC.
METHODS: Using three human HCC lines (Hep3B, PLC/PRF/5 and SK-Hep-1) and one Hh-responsive human HSC line (LX-2), we developed two in vitro models of HCC-to-HSC paracrine signaling using a Transwell coculture system and HCC-conditioned media. We then evaluated the effects of these models, as well as GPC3, on HSC viability and gene expression.
RESULTS: Using our coculture and conditioned media models, we demonstrate that the three HCC lines decrease HSC viability. Furthermore, we demonstrate that recombinant GPC3 dose-dependently decreases the LX-2 viability while inhibiting the expression of Hh target genes that regulate HSC viability. Finally, GPC3's inhibitory effects on cell viability and Hh target gene expression are partially abrogated by heparin, a competitor for GPC3 binding.
CONCLUSIONS: For the first time, we show that GPC3, an HCC biomarker and Hh mediator, regulates human HSC viability by regulating Hh signaling. This expands on existing data suggesting a role for tumor-stroma interactions in the liver and suggests that GPC3 plays a role in this process.

Lee YB, Kim HJ, Jung HY, et al.
Downregulation of erythroid differentiation regulator 1 as a novel marker of skin tumors.
Int J Dermatol. 2014; 53(6):723-30 [PubMed] Related Publications
BACKGROUND: Erythroid differentiation regulator 1 is decreased in malignant melanoma. However, the expression of erythroid differentiation regulator 1 has not been reported in normal epidermis, vessel, nerve, dermal adnexae, and various skin tumors.
METHODS: To investigate the expression of erythroid differentiation regulator 1 in normal skin and various skin tumors, immunohistochemical analysis of normal skin, epidermal tumors, sebaceous tumors, and eccrine tumors was performed. The image analysis was quantitatively performed using HistoQuant(™) software.
RESULTS: Erythroid differentiation regulator 1 was strongly expressed in the nuclei of normal epidermis, sebaceous gland, eccrine gland, vessel, and nerve. Expression of erythroid differentiation regulator 1 was weak in seborrheic keratosis, sebaceous hyperplasia, and eccrine spiradenoma. Erythroid differentiation regulator 1 was rarely observed in malignant skin tumors, including squamous cell carcinoma, basal cell carcinoma, malignant melanoma, sebaceous carcinoma, and eccrine porocarcinoma.
CONCLUSIONS: The expression of erythroid differentiation regulator 1 was negatively correlated with the malignant potential in various skin tumors. The results support the role of erythroid differentiation regulator 1 in cutaneous carcinogenesis and indicate its potential as a novel marker of skin tumors.

Qi J, Dong Z, Liu J, Zhang JT
EIF3i promotes colon oncogenesis by regulating COX-2 protein synthesis and β-catenin activation.
Oncogene. 2014; 33(32):4156-63 [PubMed] Free Access to Full Article Related Publications
Translational control of gene expression has recently been recognized as an important mechanism controlling cell proliferation and oncogenesis, and it mainly occurs in the initiation step of protein synthesis that involves multiple eukaryotic initiation factors (eIFs). Many eIFs have been found to have aberrant expression in human tumors and the aberrant expression may contribute to oncogenesis. However, how these previously considered house-keeping proteins are potentially oncogenic remains elusive. In this study, we investigated the expression of eIF3i in human colon cancers, tested its contribution to colon oncogenesis and determined the mechanism of eIF3i action in colon oncogenesis. We found that eIF3i expression was upregulated in both human colon adenocarcinoma and adenoma polyps as well as in model inducible colon tumorigenic cell lines. Overexpression of ectopic eIF3i in intestinal epithelial cells causes oncogenesis by directly upregulating the synthesis of cyclooxygenase-2 (COX-2) protein and activates the β-catenin/T-cell factor 4 signaling pathway that mediates the oncogenic function of eIF3i. Together, we conclude that eIF3i is a proto-oncogene that drives colon oncogenesis by translationally upregulating COX-2 and activating the β-catenin signaling pathway. These findings imply that proto-oncogenic eIFs likely exert their tumorigenic function by regulating/altering the synthesis level of downstream tumor suppressor or oncogenes.

Niknejad N, Gorn-Hondermann I, Ma L, et al.
Lovastatin-induced apoptosis is mediated by activating transcription factor 3 and enhanced in combination with salubrinal.
Int J Cancer. 2014; 134(2):268-79 [PubMed] Related Publications
We have previously demonstrated the ability of lovastatin, a potent inhibitor of mevalonate synthesis, to induce tumor-specific apoptosis. The apoptotic effects of lovastatin were regulated in part by the integrated stress response (ISR) that regulates cellular responses to a wide variety of stress inducers. A key regulator of the ISR apoptotic response is activating transcription factor 3 (ATF3) and its target gene CHOP/GADD153. In our study, we demonstrate that in multiple lovastatin-resistant clones of the squamous cell carcinoma (SCC) cell line SCC9, lovastatin treatment (1-25 μM, 24 hr) in contrast to the parental line failed to significantly induce ATF3 expression. Furthermore, the SCC-derived cell lines SCC25 and HeLa that are sensitive to lovastatin-induced apoptosis also preferentially induce ATF3 expression compared to resistant breast (MCF-7) and prostate carcinoma (PC3)-derived cell lines. In HeLa cells shRNA targeting ATF3 expression as well as in ATF3-deficient murine embryonic fibroblasts, lovastatin-induced cytotoxicity and apoptosis were attenuated. In ex vivo HNSCC tumors, lovastatin also induced ATF3 mRNA expression in two of four tumors evaluated. Salubrinal, an agent that can sustain the activity of a key regulator of the ISR eIF2α, further increased the expression of ATF3 and demonstrated synergistic cytotoxicity in combination with lovastatin in SCC cells. Taken together, our results demonstrate preferential induction of ATF3 in lovastatin-sensitive tumor-derived cell lines that regulate lovastatin-induced apoptosis. Importantly, combining lovastatin with salubrinal enhanced ATF3 expression and induced synergistic cytotoxicity in SCC cells.

Song N, Wang Y, Gu XD, et al.
Effect of siRNA-mediated knockdown of eIF3c gene on survival of colon cancer cells.
J Zhejiang Univ Sci B. 2013; 14(6):451-9 [PubMed] Free Access to Full Article Related Publications
Eukaryotic initiation factor subunit c (eIF3c) has been identified as an oncogene that is over-expressed in tumor cells and, therefore, is a potential therapeutic target for gene-based cancer treatment. This study was focused on investigating the effect of small interfering RNA (siRNA)-mediated eIF3c gene knockdown on colon cancer cell survival. The eIF3c gene was observed to be highly expressed in colon cancer cell models. The expression levels of the gene in eIF3c siRNA infected and control siRNA infected cells were compared via real-time polymerase chain reaction (PCR) and western blotting analysis. Cell proliferation levels were analyzed employing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays. Furthermore, the effects of eIF3c gene knockdown on the cell cycle and apoptosis were analyzed using flow cytometry. The results showed that suppression of eIF3c expression significantly (P<0.001) reduced cell proliferation and colony formation of RKO colon cancer cells. The cell cycle was arrested by decreasing the number of cells entering S phase. Further, apoptosis was induced as a result of eIF3c knockdown. Collectively, eIF3c deletion effectively reduced the survival of colon cancer cells and could be used as a therapeutic tool for colon cancer therapy.

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