Correction: A Screen Identifies the Oncogenic Micro-RNA miR-378a-5p as a Negative Regulator of Oncogene-Induced Senescence.
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ABSTRACT:
SUBMITTER: Kooistra SM
PROVIDER: S-EPMC9302827 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Oncogene-induced senescence (OIS) can occur in response to hyperactive oncogenic signals and is believed to be a fail-safe mechanism protecting against tumorigenesis. To identify new factors involved in OIS, we performed a screen for microRNAs that can overcome or inhibit OIS in human diploid fibroblasts. This screen led to the identification of miR-378a-5p and in addition several other miRNAs that have previously been shown to play a role in senescence. We show that ectopic expression of miR-378a-5p reduces the expression of several senescence markers, including p16(INK4A) and senescence-associated β-galactosidase. Moreover, cells with ectopic expression of miR-378a-5p retain proliferative capacity even in the presence of an activated Braf oncogene. Finally, we identified several miR-378a-5p targets in diploid fibroblasts that might explain the mechanism by which the microRNA can delay OIS. We speculate that miR-378a-5p might positively influence tumor formation by delaying OIS, which is consistent with a known pro-oncogenic function of this microRNA.
| S-EPMC3961217 | biostudies-literature
Project description:BACKGROUND:Functional characterization of non-coding elements in the human genome is a major genomic challenge and the maturation of genome-editing technologies is revolutionizing our ability to achieve this task. Oncogene-induced senescence, a cellular state of irreversible proliferation arrest that is enforced following excessive oncogenic activity, is a major barrier against cancer transformation; therefore, bypassing oncogene-induced senescence is a critical step in tumorigenesis. Here, we aim at further identification of enhancer elements that are required for the establishment of this state. RESULTS:We first apply genome-wide profiling of enhancer-RNAs (eRNAs) to systematically identify enhancers that are activated upon oncogenic stress. DNA motif analysis of these enhancers indicates AP-1 as a major regulator of the transcriptional program induced by oncogene-induced senescence. We thus constructed a CRISPR-Cas9 sgRNA library designed to target senescence-induced enhancers that are putatively regulated by AP-1 and used it in a functional screen. We identify a critical enhancer that we name EnhAP1-OIS1 and validate that mutating the AP-1 binding site within this element results in oncogene-induced senescence bypass. Furthermore, we identify FOXF1 as the gene regulated by this enhancer and demonstrate that FOXF1 mediates EnhAP1-OIS1 effect on the senescence phenotype. CONCLUSIONS:Our study elucidates a novel cascade mediated by AP-1 and FOXF1 that regulates oncogene-induced senescence and further demonstrates the power of CRISPR-based functional genomic screens in deciphering the function of non-coding regulatory elements in the genome.
| S-EPMC6097335 | biostudies-literature
Project description:Evaluating the expression levels of miR-378a-5p both in a large melanoma patient cohort from The Cancer Genome Atlas database and in melanoma patients from our Institute, we found that miR-378a-5p is upregulated in metastatic melanoma specimens. miR-378a-5p expression was also increased in melanoma cells resistant to target therapy, and decreased in response to drug treatment. We also demonstrated that overexpression of miR-378a-5p enhances in vitro cell invasion and migration, and facilitates the ability of melanoma cells to form de novo vasculogenic structures. While performing downstream targeting studies, we confirmed the ability of miR-378a-5p to modulate the expression of known target genes, such as SUFU, FUS-1, and KLF9. Luciferase-3'UTR experiments also identified STAMBP and HOXD10 as new miR-378a-5p target genes. MMP2 and uPAR, two HOXD10 target genes, were positively regulated by miR-378a-5p. Genetic and pharmacologic approaches inhibiting uPAR expression and activity evidenced that the in vitro tumor-promoting functions of miR-378a-5p, were in part mediated by uPAR. Of note miR-378a-5p was also able to increase VEGF, as well as in vitro and in vivo angiogenesis. Finally, genetic and pharmacologic modulation of Bcl-2 evidenced Bcl-2 ability to regulate miR-378a-5p expression. In conclusion, to the best of our knowledge, this is the first study demonstrating that miR-378a-5p acts as an oncogenic microRNA in melanoma.
| S-EPMC7021836 | biostudies-literature
Project description:During this last decade, the development of prosenescence therapies has become an attractive strategy as cellular senescence acts as a barrier against tumour progression. In this context, CDK4/6 inhibitors induce senescence and reduce tumour growth in breast cancer patients. However, even though cancer cells are arrested after CDK4/6 inhibitor treatment, genes regulating senescence in this context are still unknown limiting their antitumour activity. Here, using a functional genome-wide CRISPR/Cas9 genetic screen we found several genes that participate in the proliferation arrest induced by CDK4/6 inhibitors. We find that downregulation of the coagulation factor IX (F9) using sgRNA and shRNA prevents the cell cycle arrest and senescent-like phenotype induced in MCF7 breast tumour cells upon Palbociclib treatment. These results were confirmed using another breast cancer cell line, T47D, and with an alternative CDK4/6 inhibitor, Abemaciclib, and further tested in a panel of 22 cancer cells. While F9 knockout prevents the induction of senescence, treatment with a recombinant F9 protein was sufficient to induce a cell cycle arrest and senescence-like state in MCF7 tumour cells. Besides, endogenous F9 is upregulated in different human primary cells cultures undergoing senescence. Importantly, bioinformatics analysis of cancer datasets suggest a role for F9 in human tumours. Altogether, these data collectively propose key genes involved in CDK4/6 inhibitor response that will be useful to design new therapeutic strategies in personalised medicine in order to increase their efficiency, stratify patients and avoid drug resistance.
| S-EPMC8858321 | biostudies-literature
Project description:We carried out CRISPR-Cas9 functional screen focused on AP-1 bound enhancers that are activated upon oncogenic stress. The screen discovered Enh.AP1.OIS1 - an enhancer bound by AP1 that is required for activation of oncogene-induced senescence (OIS) response. We applied RNA-seq analysis to RASG12V-activated BJ cells transduced with either sgRNAs targeting AP-1 bound enhancer (sgRNA-69 or sgRNA71), or sgRNA targeting the target gene FOXF1 or non-targeting control sgRNA (sgNT)
2018-07-15 | GSE112458 | GEO
Project description: Not available
| S-EPMC8101183 | biostudies-literature
Project description:Senescence stimuli activate multiple tumor suppressor pathways to initiate cycle arrest and a differentiation program characteristic of senescent cells. We performed a two-stage, gain-of-function screen to select for the genes whose enhanced expression can bypass replicative senescence. We uncovered multiple genes known to be involved in p53 and Rb regulation and ATM regulation, two components of the CST (CTC1-STN1-TEN1) complex involved in preventing telomere erosion, and genes such as REST and FOXO4 that have been implicated in aging. Among the new genes now implicated in senescence, we identified DLX2, a homeobox transcription factor that has been shown to be required for tumor growth and metastasis and is associated with poor cancer prognosis. Growth analysis showed that DLX2 expression led to increased cellular replicative life span. Our data suggest that DLX2 expression reduces the protein components of the TTI1/TTI2/TEL2 complex, a key complex required for the proper folding and stabilization of ATM and other members of the PIKK (phosphatidylinositol 3-kinase-related kinase) family kinase, leading to reduced ATM-p53 signaling and senescence bypass. We also found that the overexpression of DLX2 exhibited a mutually exclusive relationship with p53 alterations in cancer patients. Our functional screen identified novel players that may promote tumorigenesis by regulating the ATM-p53 pathway and senescence.
| S-EPMC4743059 | biostudies-literature
Project description:New therapeutic targets for advanced colorectal cancer (CRC) are critically needed. Our laboratory recently performed an insertional mutagenesis screen in mice to identify novel CRC driver genes and, thus, potential drug targets. Here, we define Transmembrane 9 Superfamily 2 (TM9SF2) as a novel CRC oncogene. TM9SF2 is an understudied protein, belonging to a well conserved protein family characterized by their nine putative transmembrane domains. Based on our transposon screen we found that TM9SF2 is a candidate progression driver in digestive tract tumors. Analysis of The Cancer Genome Atlas (TCGA) data revealed that approximately 35% of CRC patients have elevated levels of TM9SF2 mRNA, data we validated using an independent set of CRC samples. RNAi silencing of TM9SF2 reduced CRC cell growth in an anchorage-independent manner, a hallmark of cancer. Furthermore, CRISPR/Cas9 knockout of TM9SF2 substantially diminished CRC tumor fitness in vitro and in vivo. Transcriptome analysis of TM9SF2 knockout cells revealed a potential role for TM9SF2 in cell cycle progression, oxidative phosphorylation, and ceramide signaling. Lastly, we report that increased TM9SF2 expression correlates with disease stage and low TM9SF2 expression correlate with a more favorable relapse-free survival. Taken together, this study provides evidence that TM9SF2 is a novel CRC oncogene.
| S-EPMC6193042 | biostudies-literature
Project description:An apical component of the cell cycle checkpoint and DNA damage repair response is the ataxia-telangiectasia mutated (ATM) Ser/Thr protein kinase. A variant of ATM, Ser49Cys (rs1800054; minor allele frequency = 0.011), has been associated with an elevated risk of melanoma development; however, the functional consequence of this variant is not defined. ATM-dependent signalling in response to DNA damage has been assessed in a panel of patient-derived lymphoblastoid lines and primary human melanocytic cell strains heterozygous for the ATM Ser49Cys variant allele. The ATM Ser49Cys allele appears functional for acute p53-dependent signalling in response to DNA damage. Expression of the variant allele did reduce the efficacy of oncogene expression in inducing senescence. These findings demonstrate that the ATM 146C>G Ser49Cys allele has little discernible effect on the acute response to DNA damage but has reduced function observed in the chronic response to oncogene over-expression. Analysis of melanoma, naevus and skin colour genomics and GWAS analyses have demonstrated no association of this variant with any of these outcomes. The modest loss of function detected suggest that the variant may act as a modifier of other variants of ATM/p53-dependent signalling.
| S-EPMC10855307 | biostudies-literature
Project description:Cells from patients with genomic instability syndromes have high predisposition to cancer. However, little is known about whether these mutant cells have high susceptibility to oncogenic transformation. We have tested the hypothesis that a defect in maintaining genome integrity is necessary but not sufficient alone for oncogenic transformation and needs to collaborate with other signals in order to produce full oncogenic transformation. Using genetically matched primary cells deficient for the Fanconi complementation group C gene (Fancc) and the ataxia telangiectasia mutated gene (Atm), we found that certain forms of oncogenic activation and cooperation require a combination of genomic instability with increased expression of nucleophosmin (NPM) to prevent oncogenic stress-induced apoptosis or senescence. Intriguingly, co-expression of c-Myc and NPM leads to a synergistic increase in the proliferation rate in Fancc-/- or Atm-/- cells. Analysis of p53 stabilization and activation by c-Myc demonstrates that over-expression of NPM significantly reduces the accumulation of the activated p53 but not the stability of p53. Moreover, NPM is shown to enhance transforming activity of co-expressed Myc and Ras in wild-type and, to a greater degree, in Fancc-/- or Atm-/- cells, suggesting a role in oncogenic cooperation. Finally, a partial knockdown of NPM is sufficient to cause massive apoptosis in Fancc-/- or Atm-/- cells co-expressing c-Myc and Ras while sparing untransformed cells. Our study demonstrates a novel mechanism of NPM tumorigenesis by establishing NPM as a crucial inhibitor of oncogene-induced apoptosis and senescence.
| S-EPMC2850567 | biostudies-literature