Mutant p53 promotes tumor progression by the endoplasmic reticulum UDPase ENTPD5
Ontology highlight
ABSTRACT: Mutations in the p53 tumor suppressor gene are the most frequent genetic alteration in cancer and often associated with progression from benign to invasive, metastatic stages. Mutations inactivate tumor suppression by p53 and endow the protein with novel gain-of-function (GOF) activities that actively promote tumor progression, metastasis and therapy resistance. By comparative gene expression profiling of p53-mutated and p53-depleted cancer cells we identified ectonucleoside triphosphate diphosphohydrolase 5 (ENTPD5) as a mutant p53 (mutp53) target gene. A comprehensive pan-cancer analysis revealed a highly significant correlation between GOF p53 mutations and elevated expression of ENTPD5. Mechanistically, regulation of ENTPD5 by mutp53 is mediated by the histone H3 lysine 4 (H3K4) methyltransferase COMPASS complex. ENTPD5 has been shown to function in the endoplasmic reticulum as a UDPase to promote the N-glycosylation and folding of membrane proteins such as growth factor receptors and integrins. We show ENTPD5 to be a mediator of mutp53 GOF activity in clonogenic growth, architectural tissue remodeling, migration, invasion, and lung colonization in an experimental metastasis mouse model. Our study reveals N-glycosylation in the endoplasmic reticulum as a novel mechanism underlying the progression of tumors with mutp53 that could provide new possibilities for treating cancers driven by GOF p53 mutations.
Project description:Inactivating TP53 mutations lead to a loss of function of p53, but can also often result in oncogenic gain-of-function (GOF) of mutant p53 (mutp53) proteins which promote tumor development and progression. The GOF activities of TP53 mutations are well documented, but the mechanisms involved remain poorly understood. Here, we study the mutp53 interactome with IP-MS.
Project description:In the present study, we set out to explore mechanisms of mutp53 GOF by identifying new interaction partners of mutp53. Specifically, we focused on the DNA contact mutant p53R273H, one of the most common p53 hotspot mutants and the most frequent TP53 mutant in pancreatic cancer. We now report that p53R273H binds selectively to the polyubiquitin-binding protein SQSTM1/p62. The crosstalk between p53R273H and p62 leads to proteasomal degradation of several cell adhesion-associated proteins, apparently in conjunction with the Golgi apparatus, resulting in loss of cell-cell junctions and enhancement of cancer cell scattered migration and invasion. This new mechanism, which does not rely on transcriptional regulation by mutp53, is likely to contribute to mutp53 GOF in tumors whose spead is reliant on scattered cell migration.
Project description:Mutations in the DNA binding domain (DBD) of TP53 are often associated with the gain-of-function (GOF) of mutp53, resulting in pervasive transcription of chromatin regulatory genes that promote genome-wide histone methylation and acetylation. Efforts to target this tumor-promoting function of mutp53 remain elusive. Here, we therapeutically exploit the GOF mechanisms of p53 codon 158 mutation, a DBD mutant found to be prevalent in lung squamous cell carcinoma. Using high throughput compound screening and combination analyses, we uncovered that mutp53R158G exhibits strong synergistic cytotoxicity to cisplatin-induced DNA stress and belinostat, a histone deacetylase inhibitor. This treatment regime acetylates mutp53, alters DNA binding motifs and upregulates TRAIP, a RING domain-containing E3 ubiquitin ligase which dephosphorylates IĸB and impedes nuclear translocation of RelA (p65), thus repressing oncogenic nuclear factor kappa-B (NF-ĸB) signalling and inducing apoptosis. This mechanistic intervention was validated with other acetylators of mutp53 and in several cancer models. Given that this transcriptional modulation and cytotoxic vulnerability appears inapt in p53 wild-type (WT) or null cells, our work provides a novel therapeutic opportunity in Arg158 15 -mutp53 tumors utilizing a regimen consisting of DNA-damaging agents and mutp53 acetylators, which is currently being pursued clinically.
Project description:Mutations in the DNA binding domain (DBD) of TP53 are often associated with the gain-of-function (GOF) of mutp53, resulting in pervasive transcription of chromatin regulatory genes that promote genome-wide histone methylation and acetylation. Efforts to target this tumor-promoting function of mutp53 remain elusive. Here, we therapeutically exploit the GOF mechanisms of p53 codon 158 mutation, a DBD mutant found to be prevalent in lung squamous cell carcinoma. Using high throughput compound screening and combination analyses, we uncovered that mutp53R158G exhibits strong synergistic cytotoxicity to cisplatin-induced DNA stress and belinostat, a histone deacetylase inhibitor. This treatment regime acetylates mutp53, alters DNA binding motifs and upregulates TRAIP, a RING domain-containing E3 ubiquitin ligase which dephosphorylates IĸB and impedes nuclear translocation of RelA (p65), thus repressing oncogenic nuclear factor kappa-B (NF-ĸB) signalling and inducing apoptosis. This mechanistic intervention was validated with other acetylators of mutp53 and in several cancer models. Given that this transcriptional modulation and cytotoxic vulnerability appears inapt in p53 wild-type (WT) or null cells, our work provides a novel therapeutic opportunity in Arg158 15 -mutp53 tumors utilizing a regimen consisting of DNA-damaging agents and mutp53 acetylators, which is currently being pursued clinically
Project description:The human TP53 gene is frequently mutated in tumors and cell lines. Unlike other tumor suppressors that are commonly inactivated by deletions or nonsense mutations, the majority of p53-mutations are missense point mutations that result in the expression of a full-length protein with an altered amino acid that has lost sequence specific DNA-binding. Expression of mutant p53 (mutp53) confers advantages to tumor cells and transcriptional regulation of several genes mediating the beneficial effects has been shown to play a role. However, molecular mechanisms of transcriptional regulation by mutp53 are still poorly understood. We used the glioblastoma-derived U-251 MG human cell line endogenously expressing mutp53 protein (R273H mutation) to analyze gene expression profiles on Agilent Whole Human Genome Microarray after transient and stable depletion of mutp53 expression. Gene expression data was correlated with a ChIP study on a custom tiling array to understand the contribution of endogenously expressed mutp53 to transcriptional regulation. This series of microarray experiments contains the gene expression profiles of glioblastoma-derived U-251 MG human cell lines engineered to constitutively express a p53-specific shRNA or scrambled control shRNA. To reverse the effect of mutp53 depletion, stable clones were modified by stable integration of a mutp53-R273H expression construct or empty pCDNA3 vector as a control. In addition, we performed gene expression analysis of U-251 MG cells transiently transfected with p53-specific siRNA or control siRNA (3 biological replicates each).
Project description:Study of the effects of the VCP knockdown. VCP (p97, yeast cdc48) is a hexameric AAA ATPase involved in various cellular functions including degradation of proteins by the ubiquitin-proteasome system. We examine the consequences of the reduction of VCP levels after RNAi of VCP in HeLa cells. We find ~30 transcripts upregulated in a sequence independent manner. Those transcripts encode proteins involved in endoplasmic reticulum stress, apoptosis, and amino acid starvation.
Project description:The human TP53 gene is frequently mutated in tumors and cell lines. Unlike other tumor suppressors that are commonly inactivated by deletions or nonsense mutations, the majority of p53-mutations are missense point mutations that result in the expression of a full-length protein with an altered amino acid that has lost sequence specific DNA-binding. Expression of mutant p53 (mutp53) confers advantages to tumor cells and transcriptional regulation of several genes mediating the beneficial effects has been shown to play a role. However, molecular mechanisms of transcriptional regulation by mutp53 are still poorly understood. We used the glioblastoma-derived U-251 MG human cell line endogenously expressing mutp53 protein (R273H mutation) to analyze gene expression profiles on Agilent Whole Human Genome Microarray after transient and stable depletion of mutp53 expression. Gene expression data was correlated with a ChIP study on a custom tiling array to understand the contribution of endogenously expressed mutp53 to transcriptional regulation.
Project description:Missense mutations in the TP53 gene are frequent genetic alterations in human tumor tissue and cell lines. In contrast to wild-type p53, the mutant p53 (mutp53) protein has lost the transcriptional activity towards pro-apoptotic and growth arrest genes, but retained the property to interact with DNA in a structure-specific fashion. Expression of mutp53 is advantageous for tumor cells, however the molecular mechanism of mutp53 action is still not known. We used the glioblastoma-derived U-251 MG human cell line to analyze DNA binding of mutant p53 (R273H mutation) on a Nimblegen custom 135k tiling array and to correlate mutp53 binding regions with the epigenetic state and occupation by other transcription factors (ETS1 and SP1). We found that mutp53-binding regions are G/C-rich and are located around transcriptional start sites (TSS) of many protein-coding genes, which in most cases are active, but are not always regulated upon transient mutp53 depletion. We propose a model which does not only rely on interactions of mutp53 with diverse transcriptional regulators at active promoters, but primarily is based on a DNA binding activity of mutp53.
Project description:Using human U251 glioblastoma cells with endogenous mutp53 expression as a model, we performed a ChIP-chip analysis of mutp53 binding sites on a custom tiling array, coupled with global expression profiling and an analysis of the epigenetic status of mutp53 regulated promoters. Mutp53 binds preferentially, and independent of other transcription factors (e.g. ETS1 and SP1), to G/C-rich DNA stretches around transcriptional start sites (TSS) of many genes. Mutp53-bound regions are frequently located in CpG islands and are highly prone to adopt non-B DNA conformation(s). Analysis of the transcriptional status of mutp53-regulated genes demonstrated that mutp53 generally modulates transcription from active promoters marked by H3K4me3. Based on our data we propose a dual mode model of mutp53 GOF, which includes both stochastic and deterministic components. On a local scale, mutp53 acts as a basal transcriptional co-factor that has the potential to bind autonomously and selectively to non-B DNA structures around TSSs of active genes and to modulate transcription rates of many genes in a context and stimulus-dependent fashion. Resulting stochastic alterations generate transcriptional plasticity and enhance transcriptional competence on a global scale. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
Project description:Modern omics technologies allow us obtaining global information on different types of biological networks. However, integrating these different types of analyzes into a coherent framework for a comprehensive biological interpretation remains challenging. Here, we present a conceptual framework that integrates protein interaction, phosphoproteomics and transcriptomics data. Applying this method to analyze HRAS signaling from different subcellular compartments shows that spatially-defined networks contribute specific functions to HRAS signaling. Changes in HRAS protein interactions at different sites lead to different kinase activation patterns that differentially regulate gene transcription. HRAS mediated signaling is the strongest from the plasma membrane, but it regulates the largest number of genes from the endoplasmic reticulum. The integrated networks provide a topologically and functionally resolved view of HRAS signaling. They reveal new HRAS functions including the control of cell migration from the endoplasmic reticulum and p53 dependent cell survival when signaling from the Golgi apparatus.