Splice-altering TP53 missense mutations: Drivers of functional loss and therapeutic targets via RNA modulation
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE297670 | GEO | 2026/05/31
REPOSITORIES: GEO
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Project description:Splice-altering TP53 missense mutations: Drivers of functional loss and therapeutic targets via RNA modulation
| PRJNA1265660 | ENA
Project description:Mutational inactivation of TP53 is a common event in cancer. Germline mutations in TP53 that inactivate this protein also occur in Li Fraumeni syndrome, which predisposes to early-onset cancer. In addition, there are dozens of other germline variants in TP53 that do not completely inactivate the function of this protein. In many cases studies have shown strong support for an impact of these lesser-functioning hypomorphs with increased cancer risk in humans and mouse models; however, the majority of these hypomorphs have yet to be categorized as pathogenic in clinical genetics databases. There is thus need for a functional assay to distinguish lesser-functioning hypomorphic p53 variants from wild type p53, or benign, fully-functional, variants. We report the surprising finding that two different African-centric genetic hypomorphs of p53, which occur in distinct functional domains of the protein, share common activities. We show that the Pro47Ser variant in the transactivation domain and the Tyr107His variant in the DNA binding domain both share increased propensity to misfold into a conformation specific for mutant p53. Moreover, cells and tissues with these variants show increased NF-B activity. We have identified a common gene signature from unstressed lymphocyte cell lines that is shared between these two, and other, genetic missense hypomorphs of TP53. We show that this gene signature successfully distinguishes wild type p53 and a benign p53 variant from lesser-functioning hypomorphic variants. These findings should allow us to better understand how hypomorphic variants contribute to cancer risk, and to better inform cancer risk in hypomorph carriers.
2023-03-01 | GSE209837 | GEO
Project description:Li-Fraumeni syndrome (LFS) is a rare, clinically and genetically heterogeneous inherited cancer syndrome. Most cases are due to mutations in TP53. CHK2 is a minor predisposing locus; we recently mapped a third locus to 1q23. In both TP53 and non-TP53 LFS, there is evidence for risk heterogeneity within and between kindreds, suggesting additional risk modifiers. Using BAC- and SNP-based microarrays, we performed genomic profiling of primary soft tissue sarcomas, osteosarcomas and matching constitutive samples of 10 LFS patients (6 with and 4 without TP53 mutations), to identify genome-wide patterns of copy number changes and loss-of-heterozygosity (LOH). Our complementing global approaches revealed several interesting patterns for TP53 and non-TP53 LFS tumors, including positive (1q/7, 3p/15, 4q/9q, 8q/19p, 9p/10q, 13/14 and 15q/18q) and negative (2q/9q, 3q/14q and 4q/6q) associations between chromosomal regions. The region containing the oncogene TWIST1 (7p21.1) was the most common gain independent of TP53 status and tumor type, while LOH of 8q11.2 with the tumor suppressor ST18 was the only region exclusively associated with non-TP53 soft tissue sarcomas. We resequenced known mutations in BRAF, KRAS and NRAS and identified somatic NRAS mutations in 2 of 10 tumors. TP53 and non-TP53 LFS tumors shared multiple hits in genes of the p53 and overlapping pathways. Although common dogma in cancer genetics holds that multiple hits in the same pathway are redundant and thus unlikely, we show that different combinations of genetic alterations in both TP53 and non-TP53 LFS tumors appear to act together in the p53 network in LFS tumorigenesis Keywords: Comparative genomic hybridization Using the Spectral Genomics dye-swap BAC arrays we studied 10 Li Fraumeni syndrome tumor cases
2008-07-16 | E-GEOD-8798 | biostudies-arrayexpress
Project description:The adaptor protein LNK (SH2B3) has emerged as an important protein in regulating B cell development B cell leukemia. Loss-of-function mutations in LNK (SH2B3) are found in Philadelphia chromosomeâlike acute lymphoblastic leukemia (Ph-like ALL), but how LNK regulates normal B cell development or promotes leukemogenesis remains unclear. We found that combined loss of Lnk and tumor suppressors Tp53 in mice triggers a highly aggressive and transplantable precursor B-ALL. This study aims to investigate the molecular mechanism by which LNK regulates B-ALL development. We performed expression profiling of bone marrow proB progenitors from WT, Tp53-/-, Lnk-/- and preleukemic healthy Tp53/Lnk double knockout (DKO) mice, as well as leukemic bone marrow cells from DKO mice that have developed B-ALL. Results suggest that Tp53-/-Lnk-/- B-ALLs display similar gene expression profiles to human Ph-like B-ALLs, suggesting this model for preclinical and molecular studies. B220+CD19+CD43+AA4.1+IgM-NK1.1-Ly6c- bone marrow proB cells were double sorted from WT, Tp53-/-, Lnk-/- and preleukemic healthy Tp53/Lnk double knockout (DKO) mice, as well as leukemic bone marrow cells from DKO mice that have developed B-ALL. RNA was isolated using miRNeasy kit from QIAGEN and processed using the NuGEN Pico kit. The microarray analysis was performed at the PENN Molecular Profiling/Genomics Facility using GeneChip Mouse Gene 2.0ST array (Affymetrix).
2016-04-01 | E-GEOD-76940 | biostudies-arrayexpress
Project description:Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with a highly penetrant and diverse tumor spectrum characterized by germline mutations in the TP53 tumor suppressor gene. To better understand how TP53 mutations predispose individuals with LFS to cancer development, we characterized tp53 R217H and R242H zebrafish lines as the first zebrafish p53 hotspot mutants (human R248 and R273H). These mutants have lost several key wildtype p53 functions and recapitulate many LFS phenotypes. Specifically, we have shown that the R217H and R242H alleles result in partial-to-no activation of key p53 target genes, are resistant to apoptosis in a dominant negative manner and exhibit a defective G1 cell-cycle checkpoint in vivo. The loss of these wildtype p53 functions predisposed the fish to develop spontaneous tumors as early as 6 months of age. Tumor histology resembles human sarcomas, a predominant LFS tumor type. tp53 R242H mutants developed tumors earlier with a higher lifetime incidence than tp53 null or R217H mutants, suggesting it is a more aggressive mutation, while the R217H allele may be hypomorphic. Additionally, we observed mutation-specific differences both in the tumor type and sex bias across tp53 null, R217H, and R242H genotypes with associated diverse transcriptomic and DNA methylome profiles, impacting metabolism, cell signalling, and biological macromolecule synthesis and degradation. These tp53 zebrafish mutants demonstrate fidelity to their human counterparts and provide new insights into underlying tumorigenesis mechanisms and kinetics, which may inform more tailored tumor surveillance approaches and novel therapeutic targets in LFS.
2024-05-29 | GSE268283 | GEO
Project description:Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with a highly penetrant and diverse tumor spectrum characterized by germline mutations in the TP53 tumor suppressor gene. To better understand how TP53 mutations predispose individuals with LFS to cancer development, we characterized tp53 R217H and R242H zebrafish lines as the first zebrafish p53 hotspot mutants (human R248 and R273H). These mutants have lost several key wildtype p53 functions and recapitulate many LFS phenotypes. Specifically, we have shown that the R217H and R242H alleles result in partial-to-no activation of key p53 target genes, are resistant to apoptosis in a dominant negative manner and exhibit a defective G1 cell-cycle checkpoint in vivo. The loss of these wildtype p53 functions predisposed the fish to develop spontaneous tumors as early as 6 months of age. Tumor histology resembles human sarcomas, a predominant LFS tumor type. tp53 R242H mutants developed tumors earlier with a higher lifetime incidence than tp53 null or R217H mutants, suggesting it is a more aggressive mutation, while the R217H allele may be hypomorphic. Additionally, we observed mutation-specific differences both in the tumor type and sex bias across tp53 null, R217H, and R242H genotypes with associated diverse transcriptomic and DNA methylome profiles, impacting metabolism, cell signalling, and biological macromolecule synthesis and degradation. These tp53 zebrafish mutants demonstrate fidelity to their human counterparts and provide new insights into underlying tumorigenesis mechanisms and kinetics, which may inform more tailored tumor surveillance approaches and novel therapeutic targets in LFS.
2024-05-22 | GSE267760 | GEO
Project description:Mutations in the TP53 gene are the most common genetic alterations in breast cancer. To investigate at a single cell level what is the gene expression network that is regulated by mutant p53 at a non-tumoral stage, we employed a pre-neoplastic mouse model harboring the germline hotspot missense mutation R172H. We thus performed scRNAseq of cells derived from the normal mammary glands of mice harboring wt or mutant p53.
2023-10-06 | GSE239706 | GEO
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.
2021-09-28 | GSE182487 | GEO
Project description:Li-Fraumeni syndrome (LFS) is a rare, clinically and genetically heterogeneous inherited cancer syndrome. Most cases are due to mutations in TP53. CHK2 is a minor predisposing locus; we recently mapped a third locus to 1q23. In both TP53 and non-TP53 LFS, there is evidence for risk heterogeneity within and between kindreds, suggesting additional risk modifiers. Using BAC- and SNP-based microarrays, we performed genomic profiling of primary soft tissue sarcomas, osteosarcomas and matching constitutive samples of 10 LFS patients (6 with and 4 without TP53 mutations), to identify genome-wide patterns of copy number changes and loss-of-heterozygosity (LOH). Our complementing global approaches revealed several interesting patterns for TP53 and non-TP53 LFS tumors, including positive (1q/7, 3p/15, 4q/9q, 8q/19p, 9p/10q, 13/14 and 15q/18q) and negative (2q/9q, 3q/14q and 4q/6q) associations between chromosomal regions. The region containing the oncogene TWIST1 (7p21.1) was the most common gain independent of TP53 status and tumor type, while LOH of 8q11.2 with the tumor suppressor ST18 was the only region exclusively associated with non-TP53 soft tissue sarcomas. We resequenced known mutations in BRAF, KRAS and NRAS and identified somatic NRAS mutations in 2 of 10 tumors. TP53 and non-TP53 LFS tumors shared multiple hits in genes of the p53 and overlapping pathways. Although common dogma in cancer genetics holds that multiple hits in the same pathway are redundant and thus unlikely, we show that different combinations of genetic alterations in both TP53 and non-TP53 LFS tumors appear to act together in the p53 network in LFS tumorigenesis Keywords: Comparative genomic hybridization
2008-07-16 | GSE8798 | GEO
Project description:Mutations and deletions in TP53 are associated with adverse outcome in patients with myeloid malignancies and developing improved therapies for TP53-mutant leukemias is of urgent need. Here we identify mutations in TET2 as the most commonly co-existing mutation in TP53 mutant acute myeloid leukemia (AML) patients. Combined hematopoietic-specific deletion of TET2 and TP53 in mice enhanced self-renewal compared to deletion of either gene alone. Tet2/Tp53 double knockout mice developed serially transplantable AML. Both mice as well as patients with AML and combined TET2/TP53 alterations upregulated innate immune signaling in malignant cells. Mice with TET2/TP53 loss had expansion of monocytic myeloid-derived suppressor cells which impaired T cell proliferation. Moreover, patients and mice with TP53/TET2 double mutant AML upregulated TIGIT ligands CD155 on malignant cells. TIGIT blocking antibodies augmented the ability of NK cells to kill Tet2/Tp53 double mutant AML cells, reduced leukemic burden, and extended the survival of TET2/TP53 double knockout mice. These data thereby identify a previously unexplored link between TET2 and TP53 mutations and highlight therapeutic means to overcome the immunosuppressive bone marrow environment in this adverse subtype of AML.
2025-05-12 | GSE285355 | GEO