RNAi-Mediated Silencing of EIF3D Alleviates Proliferation and Migration of Glioma U251 and U87MG Cells

Design, synthesis and biological evaluation of plant-derived miliusol derivatives achieve TNBC profound regression in vivo

Triple-negative breast cancer has become a major problem in clinical treatment due to its high heterogeneity, and Plant-derived drug discovery has been the focus of attention for novel anti-tumor therapeutics. In this study, Miliusol, a natural product isolated from the rarely reported plant Miliusa tenuistipitata, was identified as the lead compound, and 25 miliusol derivatives were designed and synthesized under antiproliferative activity guidance. The results revealed that ZMF-24 was demonstrated to have potent anti-TNBC proliferation with IC50 values of 0.22 μM and 0.44 μM in BT-549 cells and MDA-MB-231 cells respectively with low cytotoxicity to MCF10A cells, and could significantly downregulate proliferation and migration markers. Through RNAseq analysis, molecular docking and CETSA experiment, we found that ZMF-24 could inhibit Eukaryotic translation initiation factor 3 subunit D (EIF3D) that further disrupted the energy supply of TNBC by inhibiting glycolysis, induced profound TNBC apoptosis by stimulating persistent ER stress. Importantly, ZMF-24 exhibited remarkable anti-proliferation and anti-metastasis potential in nude mice xenograft TNBC model without obvious toxicity. Collectively, the findings demonstrate ZMF-24 has significant potential as a potent chemotherapy agent against triple-negative breast cancer.

Deciphering EIF3D's Role in Immune Regulation and Malignant Progression: A Pan-Cancer Analysis with a Focus on Colon Adenocarcinoma

Background

EIF3D, a key component of the eukaryotic translation initiation factor 3 (EIF3) complex, is critical in selectively translating mRNAs with atypical cap structures. Its relationship with colon adenocarcinoma (COAD) development and immune infiltration, however, remains under-explored. This study delves into EIF3D's role in COAD using bioinformatics and in vitro experimentation.

Materials and Methods

We analyzed EIF3D expression levels utilizing TCGA, GTEx, CPTAC, and TISIDB databases. The TISCH database and ssGSEA method helped in assessing EIF3D's link with the tumor immune microenvironment. EIF3D expression in CRC cells was gauged via real-time PCR. Cell proliferation was assessed using CCK8 and colony formation assays, while migration capabilities were tested through Transwell assays. Flow cytometry facilitated cell cycle distribution and apoptosis analysis. ChIP-qPCR identified transcription factors regulating EIF3D, and bulk sequencing explored EIF3D's pathways in promoting COAD.

Results

EIF3D upregulation is a common feature in various tumors, especially in COAD, correlating with poor prognosis in many cancer types. It showed significant associations with immune cell and cancer-associated fibroblast (CAF) infiltration across multiple tumors. Additionally, it is closely associated with molecular and immune subtypes of multiple tumors, including COAD. Single-cell analyses depicted EIF3D's distribution and proportion in CRC immune cells. In vitro findings indicated EIF3D knockdown curtailed proliferation and migration, inducing G0/G1 arrest in COAD cells. Moreover, bulk sequencing revealed EIF3D knockdown interferes with multiple cancer-related pathways, likely by curtailing cell cycle and DNA replication activities to regulate cell proliferation.

Conclusion

EIF3D emerges as a potential prognostic biomarker for tumor progression and immune infiltration, particularly in COAD, potentially predicting immunotherapy efficacy. Additionally, EIF3D represents a multifaceted target implicated in COAD's malignant progression.

EIF3B stabilizes PCNA by counteracting SYVN1-mediated ubiquitination to serve as a promotor in cholangiocarcinoma

Cholangiocarcinoma, a prevalent hepatic malignancy, exhibits a progressively rising incidence. While Eukaryotic translation initiation factor 3 subunit B (EIF3B) has been implicated in the occurrence and development of various cancers, its specific roles in cholangiocarcinoma remain unexplored. Immunohistochemical (IHC) analysis was employed to detect EIF3B/PCNA expression in cholangiocarcinoma. Cells were manipulated using short hairpin RNA (shRNA)-mediated lentiviruses or overexpression plasmids. Statistical significance was assessed using the Student's t-test and one-way ANOVA, with P < 0.05 considered statistically significant. EIF3B exhibited robust expression in cholangiocarcinoma, demonstrating a significant correlation with the pathological grade of cholangiocarcinoma patients. Furthermore, modulation of EIF3B expression, either depletion or elevation, demonstrated the ability to inhibit or enhance cholangiocarcinoma cell survival and migration in vitro. Mechanistically, we identified Proliferating Cell Nuclear Antigen (PCNA) as a downstream gene of EIF3B, driving cholangiocarcinoma. EIF3B stabilized PCNA by inhibiting PCNA ubiquitination, a process mediated by E3 ligase SYVN1. Similar to EIF3B, PCNA levels were also abundant in cholangiocarcinoma, and knocking down PCNA impeded cholangiocarcinoma development. Intriguingly, silencing PCNA attenuated the promotion induced by EIF3B overexpression. Furthermore, the elevated P21 protein level in shEIF3B RBE cells was partially attenuated after UC2288 (P21 signaling pathway inhibitor) treatment. Our findings underscored the potential of EIF3B as a therapeutic target for cholangiocarcinoma. Unraveling its functions holds promise for the development of more specific and effective targeted therapy strategies.

Emerging Roles and Mechanisms of RNA Modifications in Neurodegenerative Diseases and Glioma

Despite a long history of research, neurodegenerative diseases and malignant brain tumor gliomas are both considered incurable, facing challenges in the development of treatments. Recent evidence suggests that RNA modifications, previously considered as static components of intracellular RNAs, are in fact dynamically regulated across various RNA species in cells and play a critical role in major biological processes in the nervous system. Innovations in next-generation sequencing have enabled the accurate detection of modifications on bases and sugars within various RNA molecules. These RNA modifications influence the stability and transportation of RNA, and crucially affect its translation. This review delves into existing knowledge on RNA modifications to offer a comprehensive inventory of these modifications across different RNA species. The detailed regulatory functions and roles of RNA modifications within the nervous system are discussed with a focus on neurodegenerative diseases and gliomas. This article presents a comprehensive overview of the fundamental mechanisms and emerging roles of RNA modifications in these diseases, which can facilitate the creation of innovative diagnostics and therapeutics for these conditions.

Decreased eukaryotic initiation factors expression upon temozolomide treatment-potential novel implications for eIFs in glioma therapy

PURPOSE

Since glioma therapy is currently still limited until today, new treatment options for this heterogeneous group of tumours are of great interest. Eukaryotic initiation factors (eIFs) are altered in various cancer entities, including gliomas. The purpose of our study was to evaluate the potential of eIFs as novel targets in glioma treatment.

METHODS

We evaluated eIF protein expression and regulation in 22 glioblastoma patient-derived xenografts (GBM PDX) after treatment with established cytostatics and with regards to mutation profile analyses of GBM PDX.

RESULTS

We observed decreased expression of several eIFs upon temozolomide (TMZ) treatment independent from the phosphatidylinositol 3-kinase (PI3K)/ AKT/ mammalian target of the rapamycin (mTOR) signalling pathway. These effects of TMZ treatment were not present in TMZ-resistant PDX. Combination therapy of regorafenib and TMZ re- established the eIF/AKT/mTOR axis.

CONCLUSION

Our study provides novel insights into chemotherapeutic effects on eIF regulation in gliomas and suggests that eIFs are interesting candidates for future research to improve glioma therapy.

Breast cancer cell mesenchymal transition and metastasis directed by DAP5/eIF3d-mediated selective mRNA translation

Cancer cell plasticity enables cell survival in harsh physiological environments and fate transitions such as the epithelial-to-mesenchymal transition (EMT) that underlies invasion and metastasis. Using genome-wide transcriptomic and translatomic studies, an alternate mechanism of cap-dependent mRNA translation by the DAP5/eIF3d complex is shown to be essential for metastasis, EMT, and tumor directed angiogenesis. DAP5/eIF3d carries out selective translation of mRNAs encoding EMT transcription factors and regulators, cell migration integrins, metalloproteinases, and cell survival and angiogenesis factors. DAP5 is overexpressed in metastatic human breast cancers associated with poor metastasis-free survival. In human and murine breast cancer animal models, DAP5 is not required for primary tumor growth but is essential for EMT, cell migration, invasion, metastasis, angiogenesis, and resistance to anoikis. Thus, cancer cell mRNA translation involves two cap-dependent mRNA translation mechanisms, eIF4E/mTORC1 and DAP5/eIF3d. These findings highlight a surprising level of plasticity in mRNA translation during cancer progression and metastasis.

eIF3d: A driver of noncanonical cap-dependent translation of specific mRNAs and a trigger of biological/pathological processes

Eukaryotic initiation factor 3d (eIF3d), a known RNA-binding subunit of the eIF3 complex, is a 66 to 68-kDa protein with an RNA-binding motif and a cap-binding domain. Compared with other eIF3 subunits, eIF3d is relatively understudied. However, recent progress in studying eIF3d has revealed a number of intriguing findings on its role in maintaining eIF3 complex integrity, global protein synthesis, and in biological and pathological processes. It has also been reported that eIF3d has noncanonical functions in regulating translation of a subset of mRNAs by binding to 5'-UTRs or interacting with other proteins independent of the eIF3 complex and additional functions in regulating protein stability. The noncanonical regulation of mRNA translation or protein stability may contribute to the role of eIF3d in biological processes such as metabolic stress adaptation and in disease onset and progression including severe acute respiratory syndrome coronavirus 2 infection, tumorigenesis, and acquired immune deficiency syndrome. In this review, we critically evaluate the recent studies on these aspects of eIF3d and assess prospects in understanding the function of eIF3d in regulating protein synthesis and in biological and pathological processes.

The dark side of mRNA translation and the translation machinery in glioblastoma

Among the different types of cancer affecting the central nervous system (CNS), glioblastoma (GB) is classified by the World Health Organization (WHO) as the most common and aggressive CNS cancer in adults. GB incidence is more frequent among persons aged 45–55 years old. GB treatments are based on tumor resection, radiation, and chemotherapies. The current development of novel molecular biomarkers (MB) has led to a more accurate prediction of GB progression. Moreover, clinical, epidemiological, and experimental studies have established genetic variants consistently associated with the risk of suffering GB. However, despite the advances in these fields, the survival expectancy of GB patients is still shorter than 2 years. Thus, fundamental processes inducing tumor onset and progression remain to be elucidated. In recent years, mRNA translation has been in the spotlight, as its dysregulation is emerging as a key cause of GB. In particular, the initiation phase of translation is most involved in this process. Among the crucial events, the machinery performing this phase undergoes a reconfiguration under the hypoxic conditions in the tumor microenvironment. In addition, ribosomal proteins (RPs) have been reported to play translation-independent roles in GB development. This review focuses on the research elucidating the tight relationship between translation initiation, the translation machinery, and GB. We also summarize the state-of-the-art drugs targeting the translation machinery to improve patients’ survival. Overall, the recent advances in this field are shedding new light on the dark side of translation in GB.

Comprehensive analysis of 7-methylguanosine and immune microenvironment characteristics in clear cell renal cell carcinomas

Clear cell renal cell carcinoma (ccRCC) is one of the most common tumors in the urinary system. ccRCC has obvious immunological characteristics, and the infiltration of immune cells is related to the prognosis of ccRCC. The effect of immune checkpoint therapy is related to the dynamic changes of the tumor immune microenvironment (TIM). The 7-methylguanosine (m7G) is an additional mRNA modification ability besides m6A, which is closely related to the TIM and affects the occurrence and development of tumors. At present, the correlations between m7G and the immune microenvironment, treatment, and prognosis of ccRCC are not clear. As far as we know, there was no study on the relationship between m7G and the immune microenvironment and survival of clear cell renal cell carcinomas. A comprehensive analysis of the correlations between them and the construction of a prognosis model are helpful to improve the treatment strategy. Two different molecular subtypes were identified in 539 ccRCC samples by describing the differences of 29 m7G-related genes. It was found that the clinical features, TIM, and prognosis of ccRCC patients were correlated with the m7G-related genes. We found that there were significant differences in the expression of PD-1, CTLA4, and PD-L1 between high- and low-risk groups. To sum up, m7G-related genes play a potential role in the TIM, treatment, and prognosis of ccRCC. Our results provide new findings for ccRCC and help to improve the immunotherapy strategies and prognosis of patients.

The Roles and Regulation of m6A Modification in Glioblastoma Stem Cells and Tumorigenesis

Glioblastoma is the most common and most lethal primary malignant brain tumor. N6-methyladenosine (m6A) is a widespread and abundant internal messenger RNA (mRNA) modification found in eukaryotes. Accumulated evidence demonstrates that m6A modification is aberrantly activated in human cancers and is critical for tumorigenesis and metastasis. m6A modification is also strongly involved in key signaling pathways and is associated with prognosis in glioblastoma. Here, we briefly outline the functions of m6A and its regulatory proteins, including m6A writers, erasers, and readers of the fate of RNA. We also summarize the latest breakthroughs in this field, describe the underlying molecular mechanisms that contribute to the tumorigenesis and progression, and highlight the inhibitors targeting the factors in m6A modification in glioblastoma. Further studies focusing on the specific pathways of m6A modification could help identify biomarkers and therapeutic targets that might prevent and treat glioblastoma.

A Profound Basic Characterization of eIFs in Gliomas: Identifying eIF3I and 4H as Potential Novel Target Candidates in Glioma Therapy

Simple Summary

Gliomas are brain tumors with currently limited therapy options. Glioma growth and proliferation is regulated by the mTOR pathway together with eukaryotic initiation factors (eIFs). In this work we show a profound basic characterization of eIFs in human gliomas and demonstrate increased mRNA and protein expressions of several eIFs in gliomas compared to healthy control brain tissue. Moreover, increased eIF3I and eIF4H levels seem to have a negative influence on the survival of patients. Our work suggests eIF3I and eIF4H as potential targets for future glioma therapy.

Abstract

Glioblastoma (GBM) is an utterly devastating cerebral neoplasm and current therapies only marginally improve patients’ overall survival (OS). The PI3K/AKT/mTOR pathway participates in gliomagenesis through regulation of cell growth and proliferation. Since it is an upstream regulator of the rate-limiting translation initiation step of protein synthesis, controlled by eukaryotic initiation factors (eIFs), we aimed for a profound basic characterization of 17 eIFs to identify potential novel therapeutic targets for gliomas. Therefore, we retrospectively analyzed expressions of mTOR-related proteins and eIFs in human astrocytoma samples (WHO grades I–IV) and compared them to non-neoplastic cortical control brain tissue (CCBT) using immunoblot analyses and immunohistochemistry. We examined mRNA expression using qRT-PCR and additionally performed in silico analyses to observe the influence of eIFs on patients’ survival. Protein and mRNA expressions of eIF3B, eIF3I, eIF4A1, eIF4H, eIF5 and eIF6 were significantly increased in high grade gliomas compared to CCBT and partially in low grade gliomas. However, short OS was only associated with high eIF3I gene expression in low grade gliomas, but not in GBM. In GBM, high eIF4H gene expression significantly correlated with shorter patient survival. In conclusion, we identified eIF3I and eIF4H as the most promising targets for future therapy for glioma patients.

Genome-wide translation patterns in gliomas: An integrative view

Gliomas are the most frequent tumors of the central nervous system (CNS) and include the highly malignant glioblastoma (GBM). Characteristically, gliomas have translational control deregulation related to overactivation of signaling pathways such as PI3K/AKT/mTORC1 and Ras/ERK1/2. Thus, mRNA translation appears to play a dominant role in glioma gene expression patterns. The, analysis of genome-wide translated transcripts, together known as the translatome, may reveal important information for understanding gene expression patterns in gliomas. This review provides a brief overview of translational control mechanisms altered in gliomas with a focus on the current knowledge related to the translatomes of glioma cells and murine glioma models. We present an integrative meta-analysis of selected glioma translatome data with the aim of identifying recurrent patterns of gene expression preferentially regulated at the level of translation and obtaining clues regarding the pathological significance of these alterations. Re-analysis of several translatome datasets was performed to compare the translatomes of glioma models with those of their non-tumor counterparts and to document glioma cell responses to radiotherapy and MNK modulation. The role of recurrently altered genes in the context of translational control and tumorigenesis are discussed.

Genetic Profiles Playing Opposite Roles of Pathogenesis in Schizophrenia and Glioma

Background

Patients diagnosed with schizophrenia were found having lower risks to develop cancers, including glioma. Based on this epidemiology, we hypothesized that there were gene profiles playing opposite roles in pathogenesis of schizophrenia and glioma.

Methods

Based on GEO datasets and TCGA, key genes of schizophrenia genes on the opposite development of glioma were screened by different expressed genes (DEGs) screening, weighted gene coexpression network analysis (WGCNA), disease-specific survival (DSS), and glioma grading and verified by gene set enrichment analysis (GSEA).

Results

First, 612 DEGs were screened from schizophrenia and control brain samples. Second, 134 key genes more specific to schizophrenia were left by WGCNA, with 93 key genes having annotations in TCGA. Third, DSS of glioma helped to find 42 key gene expressions of schizophrenia oppositely associated with survival of glioma. Finally, 24 key genes showed opposite expression trends in schizophrenia and different glioma grading, i.e., the upregulated key genes in schizophrenia expressed increasingly in higher grade glioma, and vice versa. CAMK2D and MPC2 were taken as the examples and evaluated by GSEA, which indeed showed opposite trends in the same pathways of schizophrenia and glioma.

Conclusion

This workflow of selecting novel targeted genes which may have opposite roles in pathogenesis of two diseases was firstly and innovatively generated by our team. Some filtered key genes were indeed found by their potential effects in several mechanism studies, indicating our process could be effective to generate novel targeted genes. These 24 key genes may provide potential directions for future biochemical and pharmacotherapeutic research studies.

Relevance of Translation Initiation in Diffuse Glioma Biology and its Therapeutic Potential

Cancer cells are continually exposed to environmental stressors forcing them to adapt their protein production to survive. The translational machinery can be recruited by malignant cells to synthesize proteins required to promote their survival, even in times of high physiological and pathological stress. This phenomenon has been described in several cancers including in gliomas. Abnormal regulation of translation has encouraged the development of new therapeutics targeting the protein synthesis pathway. This approach could be meaningful for glioma given the fact that the median survival following diagnosis of the highest grade of glioma remains short despite current therapy. The identification of new targets for the development of novel therapeutics is therefore needed in order to improve this devastating overall survival rate. This review discusses current literature on translation in gliomas with a focus on the initiation step covering both the cap-dependent and cap-independent modes of initiation. The different translation initiation protagonists will be described in normal conditions and then in gliomas. In addition, their gene expression in gliomas will systematically be examined using two freely available datasets. Finally, we will discuss different pathways regulating translation initiation and current drugs targeting the translational machinery and their potential for the treatment of gliomas.

Combined Therapy Sensitivity Index Based on a 13-Gene Signature Predicts Prognosis for IDH Wild-type and MGMT Promoter Unmethylated Glioblastoma Patients

Glioblastoma (GBM) is one of the lethal tumors with poor prognosis. However, prognostic prediction approaches need to be further explored. Therefore, we developed an evaluation system that could be used for prognostic prediction of GBM patients. Published mRNA expression datasets from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and Chinese Glioma Genome Atlas (CGGA) were analyzed. Quantitative Realtime-PCR of signature genes and molecular aberrations of 178 Xiangya GBM patients were used for confirmation. Gene set enrichment analysis (GSEA) was performed for functional annotation. As a result, we established a 13-gene signature which named Combined Therapy Sensitivity Index (CTSI). Based on a cutoff point, we divided patients into high-risk group and low-risk group. Based on Kaplan-Meier analysis and multivariate Cox regression analysis, we found that patients in the high-risk group had a shorter overall survival time than patients in the low-risk group (p<0.001 in TCGA and CGGA datasets, p=0.047 in GSE4271 dataset, p=0.008 in Xiangya GBM cohort, HR: 1.65-3.42). By comparing the status of IDH mutation, TERT promoter mutation (TERTp-mut) and MGMT promoter methylation, CTSI was predictable in IDH wild-type (IDH-wt)/MGMT promoter unmethylated (MGMTp-unmeth) patients (p=0.037 in IDH-wt/TERTp-mut/MGMTp-unmeth subgroup, HR: 1.98; p=0.032 in IDH-wt/TERTp-wt/MGMTp-unmeth subgroup, HR: 2.09). Based on GESA, the Gene Ontology (GO) gene sets were enriched differently between CTSI high-risk and low-risk groups. Our results showed CTSI risk score can predict the prognosis of IDH-wt/MGMTp-unmeth GBM patients. Based on CTSI, combined with the status of IDH mutation, TERT promoter mutation and MGMT promoter methylation, a stepwise prognosis evaluation system which can provide precise prognosis prediction for GBM patients was established.

Cullin-3/KCTD10 complex is essential for K27-polyubiquitination of EIF3D in human hepatocellular carcinoma HepG2 cells

Eukaryotic translation initiation factor 3 subunit D (EIF3D) binds to the 5'-cap of specific mRNAs, initiating their translation into polypeptides. From a pathological standpoint, EIF3D has been observed to be essential for cell growth in various cancer types, and cancer patients with high EIF3D mRNA levels exhibit poor prognosis, indicating involvement of EIF3D in oncogenesis. In this study, we found, by mass spectrometry, that Cullin-3 (CUL3)/KCTD10 ubiquitin (Ub) ligase forms a complex with EIF3D. We also demonstrated that EIF3D is K27-polyubiquitinated at the lysine 153 and 275 residues in a KCTD10-dependent manner in human hepatocellular carcinoma HepG2 cells. Similar to other cancers, high expression of EIF3D significantly correlated with poor prognosis in hepatocellular carcinoma patients, and depletion of EIF3D drastically suppressed HepG2 cell proliferation. These results indicate that EIF3D is a novel substrate of CUL3/KCTD10 Ub ligase and suggest involvement of K27-polyubiquitinated EIF3D in the development of hepatocellular carcinoma.

The function and clinical significance of eIF3 in cancer

Abnormal regulation of gene expression is essential for tumorigenesis. Several studies indicate that regulation of oncogene expression and neoplastic transformation are controlled by subunits of eukaryotic translation initiation factors (eIFs). Eukaryotic translation initiation factor 3 (eIF3) is the largest (800 kDa) and the most complex mammalian initiation factor. It is composed of 13 non-identical polypeptides designated as eIF3a-m and plays a pivotal role in protein synthesis that bridges the 43S pre-initiation complex and eIF4F-bound mRNA. However, the functional roles of individual subunits are not yet very clear. This review presents on several of aberrant expressed eIF3 subunits which are detected in various human cancers and the associated mechanisms have been acknowledged or are still not sure. Finally, identifying novel targets and biomarkers for caner is of great importance in early diagnosis and treatment of cancer. eIF3 may be a novel target molecule in drug development for cancer treatment and prevention.

Proteomics analysis of bladder cancer invasion: Targeting EIF3D for therapeutic intervention

Patients with advanced bladder cancer have poor outcomes, indicating a need for more efficient therapeutic approaches. This study characterizes proteomic changes underlying bladder cancer invasion aiming for the better understanding of disease pathophysiology and identification of drug targets. High resolution liquid chromatography coupled to tandem mass spectrometry analysis of tissue specimens from patients with non-muscle invasive (NMIBC, stage pTa) and muscle invasive bladder cancer (MIBC, stages pT2+) was conducted. Comparative analysis identified 144 differentially expressed proteins between analyzed groups. These included proteins previously associated with bladder cancer and also additional novel such as PGRMC1, FUCA1, BROX and PSMD12, which were further confirmed by immunohistochemistry. Pathway and interactome analysis predicted strong activation in muscle invasive bladder cancer of pathways associated with protein synthesis e.g. eIF2 and mTOR signaling. Knock-down of eukaryotic translation initiation factor 3 subunit D (EIF3D) (overexpressed in muscle invasive disease) in metastatic T24M bladder cancer cells inhibited cell proliferation, migration, and colony formation in vitro and decreased tumor growth in xenograft models. By contrast, knocking down GTP-binding protein Rheb (which is upstream of EIF3D) recapitulated the effects of EIF3D knockdown in vitro, but not in vivo. Collectively, this study represents a comprehensive analysis of NMIBC and MIBC providing a resource for future studies. The results highlight EIF3D as a potential therapeutic target.

EIF3D silencing suppresses renal cell carcinoma tumorigenesis via inducing G2/M arrest through downregulation of Cyclin B1/CDK1 signaling

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.