EIF4EBP1 is transcriptionally upregulated by MYCN and associates with poor prognosis in neuroblastoma

Identification of new targets for glioblastoma therapy based on a DNA expression microarray

This study provides a comprehensive perspective on the deregulated pathways and impaired biological functions prevalent in human glioblastoma (GBM). In order to characterize differences in gene expression between individuals diagnosed with GBM and healthy brain tissue, we have designed and manufactured a specific, custom DNA microarray. The results obtained from differential gene expression analysis were validated by RT-qPCR. The datasets obtained from the analysis of common differential expressed genes in our cohort of patients were used to generate protein-protein interaction networks of functionally enriched genes and their biological functions. This network analysis, let us to identify 16 genes that exhibited either up-regulation (CDK4, MYC, FOXM1, FN1, E2F7, HDAC1, TNC, LAMC1, EIF4EBP1 and ITGB3) or down-regulation (PRKACB, MEF2C, CAMK2B, MAPK3, MAP2K1 and PENK) in all GBM patients. Further investigation of these genes and enriched pathways uncovered in this investigation promises to serve as a foundational step in advancing our comprehension of the molecular mechanisms underpinning GBM pathogenesis. Consequently, the present work emphasizes the critical role that the unveiled molecular pathways likely play in shaping innovative therapeutic approaches for GBM management. We finally proposed in this study a list of compounds that target hub of GBM-related genes, some of which are already in clinical use, underscoring the potential of those genes as targets for GBM treatment.

mTORC1 regulates cell survival under glucose starvation through 4EBP1/2-mediated translational reprogramming of fatty acid metabolism

Energetic stress compels cells to evolve adaptive mechanisms to adjust their metabolism. Inhibition of mTOR kinase complex 1 (mTORC1) is essential for cell survival during glucose starvation. How mTORC1 controls cell viability during glucose starvation is not well understood. Here we show that the mTORC1 effectors eukaryotic initiation factor 4E binding proteins 1/2 (4EBP1/2) confer protection to mammalian cells and budding yeast under glucose starvation. Mechanistically, 4EBP1/2 promote NADPH homeostasis by preventing NADPH-consuming fatty acid synthesis via translational repression of Acetyl-CoA Carboxylase 1 (ACC1), thereby mitigating oxidative stress. This has important relevance for cancer, as oncogene-transformed cells and glioma cells exploit the 4EBP1/2 regulation of ACC1 expression and redox balance to combat energetic stress, thereby supporting transformation and tumorigenicity in vitro and in vivo. Clinically, high EIF4EBP1 expression is associated with poor outcomes in several cancer types. Our data reveal that the mTORC1-4EBP1/2 axis provokes a metabolic switch essential for survival during glucose starvation which is exploited by transformed and tumor cells.

Exploration of the molecular mechanism of intercellular communication in paediatric neuroblastoma by single-cell sequencing

Neuroblastoma (NB) is an embryonic tumour that originates in the sympathetic nervous system and occurs most often in infants and children under 2 years of age. Moreover, it is the most common extracranial solid tumour in children. Increasing studies suggest that intercellular communication within the tumour microenvironment is closely related to tumour development. This study aimed to construct a prognosis-related intercellular communication-associated genes model by single-cell sequencing and transcriptome sequencing to predict the prognosis of patients with NB for precise management. Single-cell data from patients with NB were downloaded from the gene expression omnibus database for comprehensive analysis. Furthermore, prognosis-related genes were screened in the TARGET database based on epithelial cell marker genes through a combination of Cox regression and Lasso regression analyses, using GSE62564 and GSE85047 for external validation. The patients' risk scores were calculated, followed by immune infiltration analysis, drug sensitivity analysis, and enrichment analysis of risk scores, which were conducted for the prognostic model. I used the Lasso regression feature selection algorithm to screen characteristic genes in NB and developed a 21-gene prognostic model. The risk scores were highly correlated with multiple immune cells and common anti-tumour drugs. Furthermore, the risk score was identified as an independent prognostic factor for NB. In this study, I constructed and validated a prognostic signature based on epithelial marker genes, which may provide useful information on the development and prognosis of NB.

The long non-coding RNA PVT1 promotes tumorigenesis of cutaneous squamous cell carcinoma via interaction with 4EBP1

The long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) plays an oncogenic role in multiple cancers due to its high expression. However, the expression and associated regulatory mechanisms of PVT1 in cutaneous squamous cell carcinoma (cSCC) remain unclear. Our results revealed that PVT1 was highly upregulated in cSCC tissues and cSCC cell lines. To determine the functional role of PVT1 in cSCC, we constructed a stable knockdown cell model of PVT1 in the A431 and COLO16 cell lines using a lentiviral approach. Xenograft tumor experiments of nude mice in vivo, and colony formation, CCK-8, and EdU assays in vitro demonstrated that knockdown of PVT1 could widely suppress cell proliferation in vivo and in vitro. In addition, PVT1 knockdown induced cell cycle arrest and promoted apoptosis, as detected by flow cytometry analysis. Wound healing and transwell assays revealed that PVT1 knockdown significantly inhibited the migration and invasion of CSCC cell lines. To gain insight into the tumorigenic mechanism and explore the potential target molecules of PVT1, we employed label-free quantitative proteomic analysis. The GO, KEGG enrichment, and protein-protein interaction (PPI) networks suggested that 4E-binding protein 1 (4EBP1) is the possible downstream target effector of PVT1, which was validated by western blot analysis. PVT1 silencing markedly decreased 4EBP1 protein expression levels and directly bound 4EBP1 in the cytoplasm of cSCC cells. 4EBP1 overexpression counteracted the effects of PVT1 knockdown on tumorigenesis in cSCC cells, including cell proliferation, apoptosis, migration, and invasion. Our findings provide strong evidence that PVT1 is an oncogene which plays a role in tumorigenesis of cSCC, that PVT1 may interact with 4EBP1 in the cytoplasm as an underlying mechanism in cSCC carcinogenesis, and that PVT1 combined with 4EBP1 may serve as a potential new therapeutic target for cSCC.