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PubMed2025

Pharmacologic activation of Δ133p53α reduces cellular senescence in progeria patients-derived cells.

BACKGROUND: Patients with Hutchinson-Gilford progeria syndrome (HGPS) show accelerated aging phenotypes and have shortened lifespan, with implications in physiological aging processes as well. While therapeutic approaches targeting the disease-causing abnormal protein, progerin, have been developed, further efforts to explore mechanistically distinct and complementary strategies are still critical to better treatment regimens. We previously showed that lentiviral vector-driven expression of Δ133p53α, a natural inhibitory isoform of p53, rescued HGPS patients-derived fibroblasts from early entry into cellular senescence, which is a downstream event of progerin-induced DNA damage. We also performed a quantitative high-throughput screen (qHTS) of approved drug and investigational agent libraries, leading to the identification of celastrol and AZD1981 as compounds that upregulate Δ133p53α protein levels. METHODS: To investigate whether celastrol and ADZ1981 upregulate endogenous Δ133p53α in HGPS-derived fibroblasts and reduce their senescence-associated phenotypes, we performed western blot assays (Δ133p53α, progerin, and p21WAF1, which mediates p53-induced senescence and is inhibited by Δ133p53α), senescence-associated β-galactosidase (SA-β-gal) staining, enzyme-linked immunosorbent assay (IL-6, which is a proinflammatory cytokine secreted from senescent cells), and qRT-PCR assays (p21WAF1 and IL-6). RESULTS: Treatment with celastrol (0.1 μM for 24 h) or AZD1981 (10 μM for 24 h) reproducibly increased Δ133p53α expression and decreased p21WAF1 expression in two strains of fibroblasts derived from HGPS patients. These compounds reduced the percentage of SA-β-gal-positive senescent cells and the secretion of IL-6 into culture medium in both of these fibroblast strains, irrespective of their different basal levels of senescence and IL-6 secretion. These compounds had no effect on the level of progerin. CONCLUSION: Celastrol and ADZ1981 upregulate endogenous Δ133p53α and, reproducing the effects of its vector-driven expression, inhibit cellular senescence and IL-6 secretion in HGPS-derived fibroblasts. Their progerin-independent action suggests that they may synergize with currently available progerin-targeting therapies. This study also warrants further investigation of these compounds for potential applications in other diseases and conditions in which Δ133p53α-regulated senescence plays a role.

Hutchinson-Gilford progeria syndrome↗
PubMed2026

Noise-Induced Hepatic Stress Is Associated with Transglutaminase Activation and TG7 Upregulation in Rats.

OBJECTIVE: Environmental noise is increasingly recognized as a systemic stressor capable of inducing oxidative and inflammatory responses beyond the auditory system. This study aimed to investigate the effects of chronic noise exposure on transglutaminase (TG) activation, particularly TG7, and its association with hepatic stress responses in rat liver tissue. METHODS: Thirty adult male Wistar albino rats were randomly assigned to control, short-term noise exposure (LT1), and long-term noise exposure (LT2) groups. Gene expression of TG isoforms (TG1, TG2, TG3, TG6, and TG7), inflammatory markers (IL6 and TNF-&#x3b1;), and apoptotic markers (CASP3 and P53) was evaluated using quantitative real-time PCR. Total TG enzymatic activity was assessed colorimetrically. TG7 protein expression and localization were examined by immunohistochemistry and immunofluorescence. DNA integrity was evaluated by agarose gel electrophoresis. Biochemical parameters, including serum malondialdehyde (MDA), interleukin-1 beta (IL1&#x3b2;), cortisone, aspartate aminotransferase, alanine aminotransferase, glucose, insulin, and total cholesterol, were also measured. RESULTS: Noise exposure induced selective upregulation of TG isoforms, with TG7 showing the highest increase (&#x223c;10-12-fold). Total transglutaminase enzymatic activity was significantly increased in both noise-exposed groups, with a higher increase in LT1 (*** P < 0.001) and a significant increase in LT2 (** P < 0.01) compared with control, while no significant difference was observed between LT1 and LT2. IL6 and TNF-&#x3b1; increased progressively, particularly in LT2, whereas CASP3 expression was elevated in LT1 but reduced in LT2. DNA analysis revealed mild alterations in genomic integrity without clear internucleosomal fragmentation. TG7 protein showed strong localization within hepatocyte cytoplasm and perisinusoidal regions. Biochemical analysis demonstrated significant increases in MDA (up to 61.28%), IL1&#x3b2;, cortisone, liver enzymes, glucose, insulin, and total cholesterol. CONCLUSION: Chronic noise exposure induces early TG activation, particularly TG7, accompanied by sustained oxidative stress and inflammatory responses in liver tissue. These findings identify TG7 as a potential stress-responsive mediator in noise-induced hepatic injury.

Animals↗
PubMed2026

Regulation of the lncRNA NEAT1 by p53-&#x394;Np63 crosstalk modulates the DNA damage response and therapeutic efficacy in HNSCC.

Head and neck squamous cell carcinomas (HNSCCs) are characterized by recurrent genetic alterations, including the inactivation of the tumor suppressor TP53 gene and dysregulation of the TP63 gene. The TP63 gene encodes multiple isoforms, among which the N-terminal truncated isoform &#x394;Np63 is fundamental for the integrity of stratified epithelial tissues. We previously demonstrated that &#x394;Np63 represses the expression of the lncRNA NEAT1. Here, we investigated the functional crosstalk between p53 and &#x394;Np63 in modulating NEAT1 expression following genotoxic stress. We found that upon genotoxic insults, p53 activation and the concomitant downregulation of &#x394;Np63 promote NEAT1 transcription. In p53-proficient HNSCC cells, NEAT1 targeting leads to increased DNA damage, highlighting its potential role in maintaining genomic stability and facilitating efficient DNA repair. Importantly, we showed that histone deacetylase inhibitors (HDACis) upregulate NEAT1 expression independently of p53, and NEAT1 silencing enhances HDACis-induced DNA damage. Overall, our findings establish NEAT1 as an early regulator of the DNA damage response in HNSCCs and suggest that combining NEAT1 targeting with HDAC inhibition may potentiate therapeutic efficacy, particularly in TP53-mutant HNSCCs.

DNA damage↗
PubMed2008

TAp73beta and DNp73beta activate the expression of the pro-survival caspase-2S.

p73, the p53 homologue, exists as a transactivation-domain-proficient TAp73 or deficient deltaN(DN)p73 form. Expectedly, the oncogenic DNp73 that is capable of inactivating both TAp73 and p53 function, is over-expressed in cancers. However, the role of TAp73, which exhibits tumour-suppressive properties in gain or loss of function models, in human cancers where it is hyper-expressed is unclear. We demonstrate here that both TAp73 and DNp73 are able to specifically transactivate the expression of the anti-apoptotic member of the caspase family, caspase-2(S). Neither p53 nor TAp63 has this property, and only the p73beta form, but not the p73alpha form, has this competency. Caspase-2 promoter analysis revealed that a non-canonical, 18 bp GC-rich Sp-1-binding site-containing region is essential for p73beta-mediated activation. However, mutating the Sp-1-binding site or silencing Sp-1 expression did not affect p73beta's transactivation ability. In vitro DNA binding and in vivo chromatin immunoprecipitation assays indicated that p73beta is capable of directly binding to this region, and consistently, DNA binding p73 mutant was unable to transactivate caspase-2(S). Finally, DNp73beta over-expression in neuroblastoma cells led to resistance to cell death, and concomitantly to elevated levels of caspase-2(S.) Silencing p73 expression in these cells led to reduction of caspase-2(S) expression and increased cell death. Together, the data identifies caspase-2(S) as a novel transcriptional target common to both TAp73 and DNp73, and raises the possibility that TAp73 may be over-expressed in cancers to promote survival.

Binding Sites↗
PubMed2026

The potential clinical benefit of routine comprehensive genomic profiling in non-small cell lung cancer for the detection of prognostic co-mutations - A multicenter next generation sequencing study.

INTRODUCTION: Non-driver mutations such as TP53, STK11 and KEAP1 are clinically relevant in determining immunotherapy efficacy in patients with non-small cell lung cancer (NSCLC). The aim of this study is to determine the prevalence and clinical relevance of variations in TP53, STK11 and KEAP1 in patients in the analysis of NSCLC, using targeted next-generation sequencing. METHODS: This real-life prospective multicenter cohort study from July 2022 until October 2023 utilized samples of patients in the analysis of NSCLC. The samples were subjected to a targeted DNA NGS panel and, if indicated, RNA sequencing. The outcome of the molecular diagnostics was retrieved, including driver alterations and more in-depth analysis of TP53, STK11 and KEAP1. RESULTS: In 134 of the 437 samples an actionable genomic alteration (AGA) was detected. Of the remaining samples, 213 carried a mutation in either TP53, STK11 and/or KEAP1, while 90 harbored either variants of unknown significance (VUS) (16) or no variant (74). In-depth analysis showed 77 alterations of STK11, with 56 pathogenic and 21 VUS. Most STK11 variants were identified in exon 1, which is hypothesized to be correlated to an oncogenic isoform. Moreover, variants in KEAP1 were mostly VUS, with 48 VUS and 24 mutations. Lastly, 264 TP53 alterations, of which 249 pathogenic and 15 VUS, occurred, with an even spread in the DNA-binding domain. CONCLUSION: This study demonstrated the broad spectrum of variants in STK11, KEAP1 and TP53 in routine panel-based DNA NGS, with 70.3% of the samples without AGA showing a potential clinically relevant mutation in TP53, STK11 and/or KEAP1.

Humans↗