Project description:To compare the impact of several TP53 mutant variants in an isogenic setting, different TP53 mutations were introduced in HCT116 colorectal carcinoma cells. This parental cell line is wild-type for TP53 and shows a prototypical p53 response. To ensure unambigous genotype-phenotype correlations, the cell were haploidized prior to CRISPR-editing by introducing inactivating deletions of intronic splicing into one of the two TP53 alleles, leaving only one functional copy of TP53. The remaining TP53 allele was altered by inserting a LoxP-flanked transcriptional stop cassette (Lox-Stop-Lox, LSL) into intron 4, which allowed reversible silencing of TP53 expression. The LSL cassette was then specifically targeted with CRISPR/Cas9 to introduce a variety of different mutant p53 alleles. The competency of the mutated p53 allele to induce a p53 response upon activation using Nutlin-3a was then assessed in an RNAseq experiment.
Project description:Background: Although TP53 gain-of-function (GOF) mutations promote cancer survival, its effect on EGFR-TKI efficacy remains unclear. We established EGFR-mutant lung cancer cell lines expressing various TP53 genotypes using CRISPR-Cas9 technology and found that TP53-GOF mutant cells develop an early resistance to EGFR-TKI osimertinib.The goal of this study is to elucidate the mechanisms underlying resistance to osimertinib treatment in TP53 GOF mutations through comprehensive gene analysis using ChIP-seq.
Project description:To compare the impact of CRISPR-egineered R175 TP53 mutant variants in HCT116 and H460 cells, mutations at the amino acid position 175 were generated systematically by CRISP/Cas9 editing. Here, genomic amplicon regions covering the TP53 Exons 5 were sequenced via targeted sequencing.
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.
Project description:Background: Although TP53 gain-of-function (GOF) mutations promote cancer survival, its effect on EGFR-TKI efficacy remains unclear. We established EGFR-mutant lung cancer cell lines expressing various TP53 genotypes using CRISPR-Cas9 technology and found that TP53-GOF mutant cells develop an early resistance to EGFR-TKI osimertinib.The goal of this study is to elucidate the mechanisms underlying resistance to osimertinib treatment in TP53 GOF mutations through comprehensive gene analysis using RNA-seq with next-generation sequencing (NGS). Methods: Total RNA was isolated from PC-9 cells overexpressing TP53 R248Q mutation (PC9/p53R248Q: TP53 GOF mutation) and PC-9 cells overexpressing empty vector plasmid (PC9/p53EV: TP53 null) treated with DMSO or osimertinib for 24hours, using the RNeasy Micro Kit , in accordance with the manufacturer’s instructions. RNA samples were quantified by NanoDrop-2000 spectrophotometer, and the quality was confirmed with a 2200 TapeStation. rRNA was removed using MGI Easy rRNA Depletion Kit according to manufacturer's instructions followed by library construction using MGIEasy RNA Directional Library Prep Set (MGI). MGI DNBseq-G400 FAST was used to perform the amplicons deep sequencing following the standard operation protocol. The sequence format was 150bp pair read for all samples. All sequencing reads were trimmed low-quality bases and adapters with Trimmomatic (v.0.38) , and RNA sequencing reads were mapped to hg38 using HISAT2 software . Raw counts for each gene were estimated in each sample using RSEM version 1.3.0 and Bowtie 2. Calculation of the log fold-change (log FC) and p-value were performed using edgeR. Results: We explored the functions of specifically upregulated genes in TP53 GOF mutation after osimertinib treatment by KEGG pathway-enrichment analysis and found that the cytokine-cytokine receptor interaction was the most significantly altered pathway. Hallmark pathway analysis identified the TNF-α/NF-κB pathway was significantly enriched. Furthermore, TRRUST analysis showed enhanced activity of transcription factors especially RELA (p65) and NF-kB1. Conclusions: TP53 GOF mutaion induces osimertinib resistance by activating TNF-α/NF-κB pathway.
Project description:High-grade serous ovarian cancer originates in the fallopian tube and is characterized by ubiquitous mutations in TP53. Here, we generated TP53 single-, TP53/BRCA1 and TP53/MYC double- and TP53/BRCA1/MYC triple-mutant subclones of the fallopian tube-derived cell line FNE1 using CRISPR/Cas9. These mutant subclones were subsequently subjected to RNA sequencing to determine the impact of these oncogenic mutations on signaling pathways.
Project description:Comparison of the TP53 wild-type myeloma cell line AMO1 with the CRISPR/Cas9 engineered AMO1 cell line named UMC901. UMC901 harbors bi-allelic alterations to TP53: TP53 del/mut. Analysis of impact of TP53 alterations on gene transcription and identification of affected pathways by transcriptome-wide differential gene expression analysis.
Project description:Genome-wide copy number variation was measured in TP53 mutation negative ovarian tumours. Analysis described in "Driver mutations in TP53 are ubiquitous in high grade serous carcinoma of the ovary" (Ahmed et al., 2010)
Project description:Background: Gene expression profiling of breast carcinomas has increased our understanding of the heterogeneous biology of this disease and promises to impact clinical care. The aim of this study was to evaluate the prognostic value of gene expression-based classification along with established prognostic markers and mutation status of the TP53 gene, in a group of breast cancer patients with long-term (12-16 years) follow-up. Methods: The clinical and histopathological parameters of 200 breast cancer patients were studied for their effects on clinical outcome using univariate/multivariate Cox regression. The prognostic impact of mutations in the TP53 gene, identified using TTGE and sequencing, was also evaluated. Eighty of the samples were analyzed for gene expression using 42K cDNA microarrays and the patients were assigned to five previously defined molecular expression groups. The strength of the gene expression based classification versus standard markers was evaluated by adding this variable to the Cox regression model used to analyze all samples. Results: Both univariate and multivariate analysis showed that TP53 mutation status, tumor size and lymph node status were the strongest predictors of breast cancer survival for the whole group of patients. Analyses of the patients with gene expression data showed that TP53 mutation status, gene expression based classification, tumor size and lymph node status were significant predictors of survival. The TP53 mutation status showed strong association with the ?basal-like? and ?ERBB2+? gene expression subgroups, and tumors with mutation had a characteristic gene expression pattern. Conclusions: TP53 mutation status and gene-expression based groups are important survival markers of breast cancer, and these molecular markers may provide prognostic information that complements clinical variables. The study adds experience and knowledge to an ongoing characterization and classification of the disease. Experiment set consisting of 80 primary breast carcinomas collected at Ulleval University Hospital (ULL-samples), Oslo, Norway from 1990-94, and one normal sample from breast reduction surgery.