Project description:Hyperactivated glycolysis is a metabolic hallmark of most cancer cells. Although sporadic information has revealed that glycolytic metabolites possess non-metabolic functions as signaling molecules, it remains largely elusive how these metabolites interact with and functionally regulate their binding targets. Here we introduce a Target Responsive Accessibility Profiling (TRAP) approach that measures ligand binding-induced accessibility changes for target identification through globally labeling reactive proteinaceous lysines. With TRAP, we mapped 913 responsive target candidates and 2,487 interactions for 10 major glycolytic metabolites in a model cancer cell line. The wide targetome depicted by TRAP unveils diverse regulatory modalities of glycolytic metabolites involving direct perturbation of carbohydrate metabolism enzymes, intervention of an orphan transcriptional protein’s activity, and modulation of targetome-level acetylation. These results deepen our understanding of how glycolysis orchestrates signaling pathways in cancer cells in support of their survival and inspire future exploitation of the glycolytic targetome for cancer therapy development.
Project description:we report a Target Responsive Accessibility Profiling (TRAP) approach for the global and quantitative analysis of glycolytic metabolites targetome in native cancer cell milieu.
Project description:In this work, we showed that the re-expression of miR-26a in DU-145 prostate cancer cells restored the tumor suppressor activity of miR-26a. To discover the genes and pathways elicited by miR-26a re-expression, we used the miRNA pull out assay to capture and the Next Generation Sequencing to identify the miR-26a targets. Data showed that: i) miR-26a captured both non-coding and coding RNAs; ii) 46% of transcripts were putative miR-26a targets according to target prediction algorithms; iii) 21 pathways were significantly enriched and the “Pathway in Cancer” was among those comprising the largest number of genes, including BIRC5 that we experimentally validated. Accordingly, the detection of cell proliferation-related events showed that miR-26a exerted its tumor suppressor activity at several levels, by decreasing the survival, impairing the migration of tumor cells and by inducing both apoptosis and cell cycle block. In conclusion, we showed that the collection of miR-26a interacting transcripts (miR-26a/targetome) represented a fruitful platform to decipher the miR-26a-dependent gene expression networks. In perspective the availability of miRNA-specific and tumor-specific targetomes will allow the discovery of new druggable tumor genes and pathways.
Project description:Abnormal tumor vessels promote metastasis and impair chemotherapy. Hence, tumor vessel normalization (TVN) by targeting endothelial cells (ECs) is emerging as anti-cancer treatment. Here, we show that tumor ECs (TECs) have a hyper-glycolytic metabolism, shunting glycolytic intermediates to nucleotide synthesis. EC haplo-deficiency or blockade of the glycolytic activator PFKFB3 did not affect tumor growth, but reduced cancer cell intra- and extravasation and metastasis by normalizing tumor vessels, which improved vessel maturation and perfusion. Mechanistically, PFKFB3 inhibition tightened the vascular barrier by reducing VE-cadherin endocytosis in ECs and rendering glycolytic pericytes more quiescent; it also lowered the expression of cancer cell adhesion molecules in ECs. Additionally, PFKFB3-blockade treatment improved chemotherapy. Considering TEC metabolism for anti-cancer treatment might thus merit further attention.
Project description:miR-28-5p is downregulated in some tumor tissues in which it has been demonstrated to have a tumor suppressor (TS) activity. Here, we demonstrate that miR-28-5p acts as a TS in prostate cancer (PCa) cells affecting cell proliferation/survival as well as migration and invasion. Using the miRNA pull out assay and next generation sequencing we collected the complete repertoire of miR-28-5p targets obtaining a data set (miR-28-5p targetome) of 191 mRNAs. Filtering the targetome with TargetScan 7, PITA and RNA22 we found that the 61% of the transcripts had miR-28-5p binding sites. To assign a functional value to the captured transcripts, we grouped the miR-28-5p targets into gene families with annotated function and showed that six transcripts belong to the transcription factor category. Among them we selected SREBF2, a gene with increasing importance in PCa. We validated miR-28-5p/SREBF2 interaction demonstrating that SREBF2 inhibition affects almost all the tumor processes affected by the miR-28-5p re-expression, suggesting that SREBF2 is an important mediator of miR-28-5p TS activity. Our findings support the identification of the targetome of cancer-related miRNAs as a tool to discover genes and pathways fundamental for tumor development and potential new targets for anti-tumor therapy.
Project description:To elucidate miRNA-mediated temporal crosstalk during productive infection, we identified genome-wide miRNA target sites using Argonaute-crosslinking and immunoprecipitation followed by high-throughput sequencing (AGO-CLIPseq) in human cytomegalovirus (HCMV)-infected cells and evaluated the targeting efficacy by applying our new AGO-CLIPseq enrichment (ACE)-scoring algorithm. To uncover the miRNA targetome in uninfected or infected human foreskin fibroblasts with HCMV (24, 48 and 72 post-infection hour) were subjected to take AGO-CLIPseq as well as mRNAseq/smallRNAseq.
Project description:The metabolic adaptation of eukaryotic cells to hypoxia involves increasing dependence upon glycolytic ATP production, an event with consequences for both cell bioenergetics and cell fate. This response is regulated at the transcriptional level by HIF-1-dependent transcriptional upregulation of all ten glycolytic enzymes. However, this response alone does not account for the levels of ATP produced in hypoxia. Here, we investigated additional mechanisms of regulating glycolysis in hypoxia. We found that both intestinal epithelial cells treated with inhibitors of transcription and translation and human platelets (which lack nuclei) maintained the capacity for hypoxia-induced glycolysis, suggesting the involvement of a non-transcriptional component to the hypoxia-induced metabolic switch to a highly glycolytic phenotype. Mass spectrometric analysis of the interactome of immunoprecipitated rate-limiting glycolytic enzymes identified hypoxia-sensitive complexes comprising multiple glycolytic enzymes and glucose transporters in intestinal epithelial cells. Surprisingly, the formation of glycolytic complexes, though not dependent upon transcription, occurs via a HIF-1?-dependent mechanism, suggesting that HIF-1? may play a moonlighting role in the formation / maintenance of glycolytic complexes. Furthermore, we provide evidence for the presence of HIF-1? in cytosolic fractions of hypoxic cells which physically associated with the glucose transporter GLUT1 and the glycolytic enzyme PFKP in a hypoxia-sensitive manner. In conclusion, we hypothesize that HIF-1? plays a role in initiation and/or maintenance of glycolytic complexes in intestinal epithelial cells under hypoxic conditions in a manner which optimizes catalytic efficiency of the pathway by facilitating substrate channeling of glycolytic intermediates between sequential pathway enzymes. In hypoxia, cells undergo a metabolic switch to increased glycolysis. This has important implications for cell behavior, phenotype, and fate in both healthy and cancerous cells. Here we describe a mechanism by which HIF-1, in addition to increasing glycolytic enzyme expression, promotes glycolysis via the formation of a metabolic complex.