Reply to "CRISPR screens are feasible in TP53 wild-type cells".
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ABSTRACT:
SUBMITTER: Haapaniemi E
PROVIDER: S-EPMC6686827 | biostudies-literature | 2019 Aug
REPOSITORIES: biostudies-literature
Publications
Reply to "CRISPR screens are feasible in TP53 wild-type cells".
Haapaniemi Emma E Botla Sandeep S Persson Jenna J Schmierer Bernhard B Taipale Jussi J
Molecular systems biology 20190801 8
Haapaniemi et al address the issues raised by Brown et al and discuss several differences between the analyses performed by the two groups. ...[more]
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Project description:A recent study by Haapaniemi et al (2018) reported that intact p53 signaling hampers CRISPR-based functional genomic screens. Brown et al report good performance of genome-scale screens in TP53 wild-type cells and reiterate best practices for CRISPR screening.
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Project description:CRISPR-Cas9 genome-wide screens were performed in retinal pigment epithelial cells (RPE1) with either wild-type TP53 gene, or a TP53-null background. Results show wild-type TP53 has minimal impact on the efficiency of CRISPR dropout screens.
2019-04-30 | GSE128210 | GEO
Project description:CRISPR screens are feasible in TP53 wild-type cells
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Project description:Tumor suppressor p53 (TP53) is frequently mutated in cancer, often resulting not only in loss of its tumor-suppressive function but also acquisition of dominant-negative and even oncogenic gain-of-function traits. While wild-type p53 levels are tightly regulated, mutants are typically stabilized in tumors, which is crucial for their oncogenic properties. Here, we systematically profiled the factors that regulate protein stability of wild-type and mutant p53 using marker-based genome-wide CRISPR screens. Most regulators of wild-type p53 also regulate p53 mutants, except for p53 R337H regulators, which are largely private to this mutant. Mechanistically, FBXO42 emerged as a positive regulator for a subset of p53 mutants, working with CCDC6 to control USP28-mediated mutant p53 stabilization. Additionally, C16orf72/HAPSTR1 negatively regulates both wild-type p53 and all tested mutants. C16orf72/HAPSTR1 is commonly amplified in breast cancer, and its overexpression reduces p53 levels in mouse mammary epithelium leading to accelerated breast cancer. This study offers a network perspective on p53 stability regulation, potentially guiding strategies to reinforce wild-type p53 or target mutant p53 in cancer.
| S-SCDT-10_1038-S44320-024-00032-X | biostudies-other
Project description:Ewing sarcoma is a pediatric cancer driven by EWS-ETS transcription factor fusion oncoproteins in an otherwise stable genomic background. The majority of tumors express wild-type TP53, and thus, therapies targeting the p53 pathway would benefit most patients. To discover targets specific for TP53 wild-type Ewing sarcoma, we used a genome-scale CRISPR-Cas9 screening approach and identified and validated MDM2, MDM4, USP7, and PPM1D as druggable dependencies. The stapled peptide inhibitor of MDM2 and MDM4, ATSP-7041, showed anti-tumor efficacy in vitro and in multiple mouse models. The USP7 inhibitor, P5091, and the Wip1/PPM1D inhibitor, GSK2830371, decreased the viability of Ewing sarcoma cells. The combination of ATSP-7041 with P5091, GSK2830371, and chemotherapeutic agents showed synergistic action on the p53 pathway. The effects of the inhibitors, including the specific USP7 inhibitor XL-188, were rescued by concurrent TP53 knockout, highlighting the essentiality of intact p53 for the observed cytotoxic activities.
| S-EPMC6080915 | biostudies-literature
Project description:Tumor protein p53 is a key regulator of several cellular pathways, including DNA repair, cell cycle and angiogenesis. Kevetrin exhibits p53‑dependent as well as‑independent activity in solid tumors, while its effects on leukemic cells remain unknown. The aim of the present study was to analyze the response of acute myeloid leukemia (AML) cell lines (TP53 wild‑type: OCI‑AML3 and MOLM‑13; and TP53‑mutant: KASUMI‑1 and NOMO‑1) to kevetrin at a concentration range of 85‑340 µM. The cellular and molecular effects of the treatment were analyzed in terms of cell growth, viability [Annexin V‑propidium iodide (PI) staining] and cell cycle alterations (PI staining). Gene expression profiling, western blotting and immunofluorescence were performed to elucidate the pathways underlying kevetrin activity. Pulsed exposure exerted no effect on the wild‑type cells, but was effective on mutant cells. After continuous treatment, significant cell growth arrest and apoptosis were observed in all cell lines, with TP53‑mutant models displaying a higher sensitivity and p53 induction. Kevetrin also displayed efficacy against TP53 wild‑type and mutant primary AML, with a preferential cytotoxic activity against blast cells. Gene expression profiling revealed a common core transcriptional program altered by drug exposure and the downregulation of glycolysis, DNA repair and unfolded protein response signatures. These findings suggest that kevetrin may be a promising therapeutic option for patients with both wild‑type and TP53‑mutant AML.
| S-EPMC7448420 | biostudies-literature
Project description:Immortalised HaCaT keratinocytes were transduced with Cas9 and the CRISPR-KO v1.1 genome-wide gRNA library. The gRNA library was prepared from genomic DNA isolated 14 days post library transduction. gRNA representation will be compared to the original CRISPR-KO v1.1 library to reveal genes essential for HaCaT survival and growth.
| EGAS00001002714 | EGA
Project description:The objective of this study is to investigate whether wild-type TP53 status in high-grade serous ovarian carcinoma is associated with poorer survival.Clinical and genomic data of 316 sequenced samples from The Cancer Genome Atlas (TCGA) ovarian high-grade serous carcinoma study were downloaded from TCGA data portal. Association between wild-type TP53 and survival was analyzed with Kaplan Meier method and Cox regression. The diagnosis of high-grade serous carcinomas was evaluated by reviewing pathological reports and high-resolution hematoxylin and eosin (H&E) images from frozen sections. The authenticity of wild-type TP53 in these tumor samples was assessed by analyzing SNP array data with ASCAT algorithm, reverse phase protein array (RPPA) data and RNAseq data.Fifteen patients with high grade serous ovarian carcinomas were identified to have wild-type TP53, which had significantly shorter survival and higher chemoresistance than those with mutated TP53. The authenticity of wild-type TP53 status in these fifteen patients was supported by SNP array, RPPA, and RNAseq data. Except four cases with mixed histology, the classification as high grade serous carcinomas was supported by pathological reports and H&E images. Using RNAseq data, it was found that EDA2R gene, a direct target of wild-type TP53, was highly up-regulated in samples with wild-type TP53 in comparison to samples with either nonsense or missense TP53 mutations.Although patients with wild-type TP53 ovarian cancer were rare in the TCGA high grade ovarian serous carcinomas cohort, these patients appeared to have a poorer survival and were more chemoresistant than those with mutated TP53. Differentially expressed genes in these TP53 wild-type tumors may provide insight in the molecular mechanism in chemotherapy resistance.
| S-EPMC4059202 | biostudies-literature
Project description: Not available
| S-EPMC6187090 | biostudies-literature
Project description:BackgroundTargeted drugs have greatly improved the therapeutic outcome of non-small cell lung cancer (NSCLC) patients compared with conventional chemotherapy, whereas about one-third of patients are so far not suitable for targeted therapy due to lack of known driver oncogenes such as a mutated receptor tyrosine kinase (RTK) genes. In this study, we aimed to identify therapeutic targets for this subgroup of NSCLC patients.MethodsWe performed genome-wide CRISPR/Cas9 screens in two NSCLC cell lines carrying wild-type TP53 and receptor tyrosine kinase (wtTP53-RTK) genes using a GeCKO v2.0 lentiviral library (containing 123411 sgRNAs and targeting 19050 genes). MAGeCKFlute was used to analyse and identify candidate genes. Genetic perturbation and pharmacological inhibition were used to validate the result in vitro and in vivo.ResultsThe Genome-wide CRISPR/Cas9 screening identified MDM2 as a potential therapeutic target for wtTP53-RTK NSCLC. Genetic and pharmacological inhibition of MDM2 reduced cell proliferation and impaired tumour growth in the xenograft model, thus confirming the finding of the CRISPR/Cas9 screening. Moreover, treatment by a selective MDM2 inhibitor RG7388 triggered both cell cycle arrest and apoptosis in several NSCLC cell lines. Additionally, RG7388 and pemetrexed synergistically blocked the cell proliferation and growth of wtTP53-RTK tumours but had limited effects for other genotypes.ConclusionsWe identified MDM2 as an essential gene and a potential therapeutic target in wtTP53-RTK NSCLC via a genome-wide CRISPR/Cas9 screening. For this subgroup, treatment by RG7388 alone or by its combination with pemetrexed resulted in significant tumour inhibition.
| S-EPMC9189421 | biostudies-literature