Eukaryotic translation initiation factors (eIFs) constitute a new class of therapeutic cancer targets. EIF3b is the major scaffold protein of eIF3 (the largest core of eIFs). We sought to define the role played by and the mechanism of action of eIF3b in patients with clear cell renal cell carcinoma (ccRCC). We found that high-level eIF3b expression in tumors was not only associated with an aggressive tumor phenotype, but was also independently prognostic for patients with ccRCC. Knockdown of eIF3b impaired the action of the Akt pathway, thus inhibiting cell proliferation by disrupting the cell cycle and triggering apoptosis. Furthermore, the epithelial-to-mesenchymal transition was impaired after eIF3b depletion, via suppression of cell migration and invasion. Additionally, eIF3b knockdown significantly inhibited the growth of subcutaneous xenografts in mice. Together, these data show that eIF3b is both a promising prognostic biomarker and a potential therapeutic target for patients with ccRCC.

BackgroundBladder cancer (BC) is the most common urological malignant tumor. In BC, aberrant DNA methylation is believed to be associated with carcinogenesis. Therefore, the identification of key genes and pathways could help determine the potential molecular mechanisms of BC development.Material/MethodsMicroarray data on gene expression and gene methylation were downloaded from the Gene Expression Omnibus (GEO) database. Abnormal methylated/expressed genes were analyzed by GEO2R and statistical software R. Gene Ontology term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed using the DAVID database and KOBAS 3.0. STRING and Cytoscape software were used to construct protein–protein interaction (PPI) networks and analyze modules of the PPI network.ResultsA total of 71 hypomethylated/upregulated genes were significantly enriched in cell–cell adhesion and blood vessel development. KEGG pathway analysis highlighted p53 signaling and metabolic pathways. Five core genes in the PPI network were determined: CDH1, DDOST, CASP8, DHX15, and PTPRF. Additionally, 89 hypermethylated/downregulated genes were found. These genes were enriched mostly in cell adhesion and signal transduction. KEGG pathway analysis revealed enrichment in focal adhesion. The top 5 core genes in the PPI network were GNG4, ADCY9, NPY, ADRA2B, and PENK. We found most of the core genes were also significantly altered in the Cancer Genome Atlas database.ConclusionsAbnormal methylated/expressed genes and key signaling pathways involved in BC were identified through integrated bioinformatics analysis. In the future, these genes may serve as biomarkers for diagnosis and therapeutic targets in BC.

Renal cell carcinoma (RCC) is the most lethal of all genitourinary malignancies. Distant metastasis represents the major cause of death in patients with RCC. Recent studies have implicated the AAA+ ATPase pontin in many cellular activities that are highly relevant to carcinogenesis. In this study, we demonstrate for the first time that pontin was up-regulated in RCC, and plays a previously unknown pro-invasive role in the metastatic progression of RCC through epithelial-to-mesenchymal transition (EMT) pathway. 28 pairs of freshly frozen clear cell RCC samples and the matched normal renal tissues analyzed by quantitative RT-PCR and western blotting demonstrated that pontin was up-regulated in clear cell RCC tissues than in normal renal tissues. In addition, immunohistochemistry was used to evaluate subcellular pontin expression in 95 RCC patients, and found that overexpression of pontin in cytoplasm positively correlated with the metastatic features, predicting unfavorable outcomes of RCC patients. Furthermore, in vitro experiments show pontin was predominantly expressed in cytoplasm of RCC cell lines, and a significant suppression of cell migration and invasion in pontin siRNA treated RCC cell lines was observed. Mechanistic studies show that pontin depletion up-regulated the E-cadherin protein and down-regulated vimentin protein, and decreased nuclear β-catenin expression, suggesting the involvement of EMT in pontin induced metastatic progression. Together, our data suggest pontin as a potential prognostic biomarker in RCC, and provide new promising therapeutic targets for clinical intervention of kidney cancers.

Background Hypopharyngeal squamous cell carcinoma (HSCC) is among the most lethal tumors encountered in the head and neck, and currently lacks satisfactory therapeutic targets. Platelet activating factor acetylhydrolase 1B3 (PAFAH1B3), a cancer-relevant metabolic driver, is reported to play a critical role in controlling tumorigenesis and aggressiveness in several types of cancers. However, the role of PAFAH1B3 in HSCC progression has not yet been identified. Methods The expression pattern of PAFAH1B3 was examined using immunohistochemistry in 83 HSCC tumor tissues and 44 paired adjacent non-tumor samples. Univariate and multivariate analyses were conducted to explore its association with prognosis of HSCC. In vitro loss-of-function assays were performed to explore the impact of PAFAH1B3 knockdown on the biological phenotype of the human HSCC cell line, ie, FaDu cells. Results PAFAH1B3 was overly expressed in the HSCC tumor tissues compared with the adjacent non-tumor samples. Moreover, high expression of PAFAH1B3 was positively correlated with cervical lymph node metastasis. PAFAH1B3 overexpression was associated with poor outcome in HSCC, but it was not an independent prognostic indicator. Furthermore, in vitro loss-of function experiments demonstrated that PAFAH1B3 knockdown suppressed cell proliferation by inducing apoptosis and disrupting cell cycle process, and the migratory and invasive capacities were also attenuated in the absence of PAFAH1B3. Conclusion This study for the first time demonstrated the clinical value and the role of PAFAH1B3 in the biological function of HSCC. This work suggested that PAFAH1B3 might serve as a potential therapeutic target for HSCC patients.

Background: Increasing evidence indicates that the dysregulation of circular RNAs (circRNAs) plays important roles in tumor progressions. Methods: In this study, we first analyzed circ-FOXO3 level in bladder cancers (BCs), and then BC cell lines were transfected with circ-FOXO3 expression vector, and cell proliferation, migration, and invasion abilities were analyzed. We also used bioinformatics tools to predict potential-binding miRNAs for circ-FOXO3, and luciferase reporter assay was used for the verification of binding miRNAs. For the further study, we analyzed potential downstream-binding mRNA for miRNA, and cell proliferation, migration and invasion abilities of it were also studied. Results: We found that circ-FOXO3 was significantly down-regulated in bladder cancer (BC) tissues compared to normal bladder tissues. We also found that circ-FOXO3 overexpression inhibited cell proliferation, migration and invasion in BC cell lines. Moreover, we demonstrated that TGFBR2 was regulated by circ-FOXO3 through sponging miR-9-5p, the knockdown of TGFBR2 or the overexpression of miR-9-5p all related to the increased BC cell proliferation, migration, and invasion. Discussion: In summary, our data showed that circ-FOXO3 was significantly downregulated in bladder cancers. circ-FOXO3 overexpression inhibits BC cell progression and metastasis. Furthermore, circ-FOXO3 regulates TGFBR2 expression through sponging miR-9-5p in BC cell lines.