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Project description:Gain of function (GOF) DNA binding domain (DBD) mutations of TP53 upregulate chromatin regulatory genes that promote genome-wide histone methylation and acetylation. Here, we therapeutically exploit the oncogenic GOF mechanisms of p53 codon 158 (Arg158) mutation, a DBD mutant found to be prevalent in lung carcinomas. Using high throughput compound screening and combination analyses, we uncover that acetylating mutp53R158G could render cancers susceptible to cisplatin-induced DNA stress. Acetylation of mutp53R158G alters DNA binding motifs and upregulates TRAIP, a RING domain-containing E3 ubiquitin ligase which dephosphorylates I?B and impedes nuclear translocation of RelA (p65), thus repressing oncogenic nuclear factor kappa-B (NF-?B) signaling and inducing apoptosis. Given that this mechanism of cytotoxic vulnerability appears inapt in p53 wild-type (WT) or other hotspot GOF mutp53 cells, our work provides a therapeutic opportunity specific to Arg158-mutp53 tumors utilizing a regimen consisting of DNA-damaging agents and mutp53 acetylators, which is currently being pursued clinically.
| S-EPMC7190866 | biostudies-literature
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
2020-02-26 | GSE129026 | GEO
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.
2020-02-26 | GSE128673 | GEO
Project description:Targeting codon 158 p53-mutant cancers via the induction of p53 acetylation
| PRJNA529799 | ENA
Project description:Targeting codon 158 p53-mutant cancers via the induction of p53 acetylation [RNA-seq]
| PRJNA529802 | ENA
Project description:Targeting codon 158 p53-mutant cancers via the induction of p53 acetylation [ChIP-seq]
| PRJNA528475 | ENA
Project description:Transcription factor and oncosuppressor protein p53 is considered as one of the most promising molecular targets that remains a high-hanging fruit in cancer therapy. TP53 gene encoding the p53 protein is known to be the most frequently mutated gene in human cancers. The loss of transcriptional functions caused by mutations in p53 protein leads to deactivation of intrinsic tumor suppressive responses associated with wild-type (WT) p53 and acquisition of new pro-oncogenic properties such as enhanced cell proliferation, metastasis and chemoresistance. Hotspot mutations of p53 are often immunogenic and elicit intratumoral T cell responses to mutant p53 neoantigens, thus suggesting this protein as an attractive candidate for targeted anti-cancer immunotherapies. In this review we discuss the possible use of p53 antigens as molecular targets in immunotherapy, including the application of T cell receptor mimic (TCRm) monoclonal antibodies (mAbs) as a novel powerful approach.
| S-EPMC8411701 | biostudies-literature
Project description:BackgroundThe mechanisms that can restore biological activity of mutant p53 are an area of high interest given that mutant p53 expression is observed in one third of prostate cancer. Here we demonstrate that Id4, an HLH transcriptional regulator and a tumor suppressor, can restore the mutant p53 transcriptional activity in prostate cancer cells.MethodsId4 was over-expressed in prostate cancer cell line DU145 harboring mutant p53 (P223L and V274F) and silenced in LNCaP cells with wild type p53. The cells were used to quantitate apoptosis, p53 localization, p53 DNA binding and transcriptional activity. Immuno-precipitation/-blot studies were performed to demonstrate interactions between Id4, p53 and CBP/p300 and acetylation of specific lysine residues within p53.ResultsEctopic expression of Id4 in DU145 cells resulted in increased apoptosis and expression of BAX, PUMA and p21, the transcriptional targets of p53. Mutant p53 gained DNA binding and transcriptional activity in the presence of Id4 in DU145 cells. Conversely, loss of Id4 in LNCaP cells abrogated wild type p53 DNA binding and transactivation potential. Gain of Id4 resulted in increased acetylation of mutant p53 whereas loss of Id4 lead to decreased acetylation in DU145 and LNCaP cells respectively. Id4 dependent acetylation of p53 was in part due to a physical interaction between Id4, p53 and acetyl-transferase CBP/p300.ConclusionsTaken together, our results suggest that Id4 regulates the activity of wild type and mutant p53. Id4 promoted the assembly of a macromolecular complex involving CBP/P300 that resulted in acetylation of p53 at K373, a critical post-translational modification required for its biological activity.
| S-EPMC3866570 | biostudies-literature
Project description:TP53 mutants (mutp53) are involved in the pathogenesis of most human cancers. Specific mutp53 proteins gain oncogenic functions (GOFs) distinct from the tumor suppressor activity of the wild-type protein. Tumor-associated macrophages (TAMs), a hallmark of solid tumors, are typically correlated with poor prognosis. Here, we report a non-cell-autonomous mechanism, whereby human mutp53 cancer cells reprogram macrophages to a tumor supportive and anti-inflammatory state. The colon cancer cells harboring GOF mutp53 selectively shed miR-1246-enriched exosomes. Uptake of these exosomes by neighboring macrophages triggers their miR-1246-dependent reprogramming into a cancer-promoting state. Mutp53-reprogammed TAMs favor anti-inflammatory immunosuppression with increased activity of TGF-β. These findings, associated with poor survival in colon cancer patients, strongly support a microenvironmental GOF role for mutp53 in actively engaging the immune system to promote cancer progression and metastasis.
| S-EPMC5823939 | biostudies-literature
Project description:The tumor suppressor p53 is lost or mutated in approximately half of human cancers. Mutant p53 not only loses its anti-tumor transcriptional activity, but also often acquires oncogenic functions to promote tumor proliferation, invasion, and drug resistance. Traditional strategies have been taken to directly target p53 mutants through identifying small molecular compounds to deplete mutant p53, or to restore its tumor suppressive function. Accumulating evidence suggest that cancer cells with mutated p53 often exhibit specific functional dependencies on secondary genes or pathways to survive, providing alternative targets to indirectly treat p53-mutant cancers. Targeting these genes or pathways, critical for survival in the presence of p53 mutations, holds great promise for cancer treatment. In addition, mutant p53 often exhibits novel gain-of-functions to promote tumor growth and metastasis. Here, we review and discuss strategies targeting mutant p53, with focus on targeting the mutant p53 protein directly, and on the progress of identifying genes and pathways required in p53-mutant cells.
| S-EPMC5664959 | biostudies-literature