The p53 pathway: positive and negative feedback loops

Single molecular profile of proteins sensing by nanopore technology

The characterization of biological macromolecules such as proteins and their interactions are crucial to understanding biological processes, disease diagnosis, and drug design. With the rapid development of proteomics, nanopore technology has emerged potentially as a single-molecule profile for huge amounts of peptides and proteins defined in the biological system, particularly for protein sequencing. This review focuses on recent advances in nanopore sensing of proteins and peptides, involving protein dynamic interactions, protein fingerprinting, and protein sequencing. These progresses will provide new perspectives to decipher the mechanisms of protein structure and function, and serve much more possible applications.

Analysis of germline-somatic mutational connections in colorectal cancer reveals differential tumorigenic patterns and a novel predictive marker for germline mutation carriers

Colorectal cancer (CRC) genetic testing of regions beyond clinical guidelines has revealed a substantial number of likely pathogenic germline mutations (GMs). It remains largely undetermined whether and how these GMs, typically located in non-mismatch repair (non-MMR) genes, are associated with the tumorigenesis of CRC. This study aimed to identify CRC-predisposing GMs among 93 cancer susceptibility genes and investigate their potential influences on CRC somatic mutational features. We secondarily aimed to investigate whether somatic ERBB2 amplification contributes to identifying GM carriers. This study incorporated a total of 3,240 Chinese CRC patients and 10,588 control individuals. CRC patients were subjected to paired tumor-normal sequencing with a 1,021-gene panel. A case-control analysis was conducted to profile the GM-associated CRC risk. A comprehensive germline-somatic association analysis was performed among 2,405 patients, with key findings subsequently validated in an independent 835-patient cohort and the TCGA CRC cohort. The case-control results supported CRC-predisposing effects of GMs in certain homologous recombination repair (HRR) and DNA damage checkpoint factor (CPF) genes, such as BRCA1/2, RecQ helicase genes, ATM, and CHEK2. HRR GMs were associated with an increased copy number alteration burden, more TP53 clonal mutations, and a higher probability of carrying somatic ERBB2 amplification. CPF GMs were inferred to have synergistic effects with ARID1A and KDM6A somatic mutations in CRC tumorigenesis. Among patients with onset age ≥55 years, stable microsatellites, and no cancer family history, ERBB2 amplification was significantly predictive of GM carriers. Our findings elucidate different germline tumorigenic patterns not driven by deficient MMR. Somatic ERBB2 amplification in CRC can serve as an indicator for germline genetic testing when traditional risk features are absent.

Nanopollutants (nZnO) amplify hypoxia-induced cellular stress in a keystone marine bivalve, Mytilus edulis

Zinc oxide nanoparticles (nZnO) are increasingly utilized in industrial, medical, and personal care products, particularly as the main ingredient in sunscreens, raising concerns about their environmental impact, especially in coastal ecosystems. The Baltic Sea, experiencing severe eutrophication, faces persistent hypoxia due to excessive nutrient runoff and limited water exchange. Simultaneously, coastal pollution from industrial and urban activities introduces nZnO, a highly biotoxic nanopollutant. The combined effects of hypoxia and nZnO contamination may amplify environmental stress, yet their interactions remain insufficiently studied. This study investigates the combined effects of nZnO exposure and fluctuating dissolved oxygen regimes (specifically short- and long-term hypoxia and subsequent reoxygenation) on Mytilus edulis, a sentinel species in these ecosystems. By assessing a range of cellular and molecular markers, including oxidative stress, oxygen sensing, protein quality control, stress response, apoptosis, and inflammation, we show that nZnO exacerbates hypoxia-induced oxidative stress, delaying redox recovery and prolonging oxidative damage during reoxygenation. Specifically, nZnO exposure maintains elevated LPO and PC levels after reoxygenation, indicating prolonged oxidative imbalance. While M. edulis typically recovers from hypoxia-induced stress, nZnO disrupts this process by impairing antioxidant defenses, prolonging HIF-1α activation, and dysregulating p53, JNK, and p38 expression, thereby interfering with normal hypoxia-reoxygenation response. Additionally, nZnO alters HSP70, Lon protease, and caspase-3 regulation, disrupting protein-folding and apoptotic pathways. These findings suggest a synergistic interaction between nZnO and hypoxia, heightening the organism's vulnerability to environmental stress and suggesting risks for marine organisms in nanoparticle-polluted, hypoxia-prone coastal regions.

Innovative prototype for the mitigation of water pollution from microplastics to safeguard the environment and health

Microplastics (MPs) are ubiquitary environmental pollutants facilitated by anthropic activities as wastewaters (WWs) not properly treated or dispersed. Our study focused on the validation of an innovative prototype filter for its future applications in WWs Treatment Plants (WWTPs) to reduce the release of MPs in the environment. The aims of the study were: The WWTPs resulted in catching 85 % and 73 % of MPs >10 and MPs <10 μm, respectively; instead, the WWTPs-prototype treated outputs showed a further reduction of 99 % and 92 % of the uncaught MPs. The mussel haemolymphs analysis showed a decrease of 100 % and 95 %, respectively, for both MPs <10 and >10 μm in filtering treatment against the normal WWTPs outputs. We revealed longer LMS times in mussels exposed to prototype-filtered WWs (29-41 min) compared to the raw output of WWTPs (18-24 min). MF and q-PCR of all studied genes revealed a reduced genotoxicity in mussels exposed to prototype-treated WWs. Hence, the results demonstrated the prototype efficacy, and it will be tested in real WWTPs at a field scale in the next study.

MTA1-DT promotes endometrial cancer growth by modulating G2/M-related gene transcription via PURα

In recent years, patients with early endometrial cancer (EC) can achieve a good prognosis through surgery. However, advanced and recurrent cases have still posed significant therapeutic challenges. This study aimed to investigate the biological function of long non-coding RNAs (lncRNAs) in EC and elucidate its underlying molecular mechanism. Through quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis, functional assays in cell lines, and bioinformatics approaches, we identified lncRNA MTA1-DT as a novel oncogenic factor in EC progression. RNA-seq and RT-qPCR analysis demonstrated that MTA1-DT was significantly upregulated with a 5-fold increase in EC cell lines compared to normal controls. Functional studies revealed that MTA1-DT promoted cell proliferation and migration. Mechanistically, we demonstrated that MTA1-DT physically interacted with purine-rich element binding protein-alpha (PURα) and facilitated its nuclear translocation, thereby enhancing its transcription factor activity. This nuclear accumulation of PURα promoted the transcription of downstream G2/M related genes, particularly EGF, leading to accelerated tumor growth. Thus, these results indicate that MTA1-DT exerts its oncogenic effects in EC through regulation of the cell cycle. Our findings establish MTA1-DT as a promising therapeutic target for EC treatment and provide new insights into the molecular mechanisms underlying EC progression.

Somatic mosaicism in the buccal mucosa reflects lifestyle and germline risk factors for esophageal squamous cell carcinoma

Clones harboring cancer driver mutations can expand in normal tissues, known as somatic mosaicism, and can be influenced by age and environmental and germline factors. Somatic mosaicism in the blood predicts the risk of hematological malignancies; however, the relevance of somatic mosaicism to solid tumors remains unclear, in part because of limited sample availability. Lifestyle habits, including alcohol consumption and tobacco smoking, and pathogenic germline variants increase the risk of developing esophageal squamous cell carcinoma (ESCC). Because somatic mosaicism in the esophagus is known to be associated with aging and lifestyle habits and considering the contiguity of squamous epithelium from the esophagus to the oral cavity, we noninvasively collected buccal mucosa samples from patients with and without ESCC using swabs of different sizes and conducted deep error-corrected sequencing of 26 cancer driver genes to obtain comprehensive landscapes of tissue remodeling by driver-mutant clones. We found that the number of mutations increased with drinking, but only in individuals with germline risks. Moreover, across positively selected genes in the buccal mucosa, mutations increased with age and smoking regardless of germline risks, whereas drinking affected only those with germline risks. The buccal mucosa of patients with ESCC was extensively remodeled, and models predicting the presence of ESCC demonstrated high accuracy with smaller swab sizes, possibly because of their higher sensitivity in detecting small mutant clones. In conclusion, we showed that buccal mucosal remodeling reflects lifestyle and germline risks, as well as age, which might be exploited for noninvasive risk assessment of ESCC.

Fingerprint of ubiquitin coupled enzyme UBC13 in health and disease

Ubiquitination is one of the most well-known post-translational modifications in eukaryotes. UBC13 is an E2 ubiquitin coupling enzyme, which interacts with different E3 ligases and exerts ubiquitination activity to assemble and synthesize lysine-63-linked (Lys63) ubiquitin strands, thus playing an important role in cell homeostasis, various diseases caused by inflammation, and the occurrence and development of cancer. In this paper, we review the structure and function of UBC13, summarize the diverse pathways it mediates, and discuss its involvement in bacterial and non-bacterial inflammatory diseases. Additionally, we explore UBC13's role in physiological damage repair mechanisms, cancer development, DNA damage repair, immune cell maturation, and function. Furthermore, We also elucidate the progress of the discovery of small molecule inhibitors targeting UBC13 and summarize their structure, which suggests that targeting UBC13 may be a potential disease treatment strategy.

Safety profile of sikamat virus and its oncolytic potential in leukemic cells and cancer stem cells

Leukaemia remains a global health concern. The oncotherapy resistance of leukaemia might be due to the existence of cancer stem cell populations. This study investigated the therapeutic potential of Sikamat virus (PRV7S), a Pteropine orthoreovirus, as an oncolytic virus against acute myeloid leukaemia (AML) and chronic myeloid leukaemia (CML). Using AML and CML cell lines (THP-1 and K562), as well as an AML-M5-derived cancer stem cell (CSC) model, PRV7S was shown to infect these leukaemic cells, replicate within them, and reduce their viability. PRV7S-induced cell death was associated with caspase-mediated apoptosis without significant cell cycle arrest. Transcriptomic and proteomic analyses revealed that PRV7S infection altered several cell death pathways, including apoptosis and necroptosis, highlighting its complex cell death mechanisms. PRV7S replicated efficiently in infected cells, though it did not cause persistent infection. An in vivo safety evaluation in immunocompetent mice demonstrated that PRV7S was well-tolerated, showing no adverse effects on survival, body weight, or histopathology, and no evidence of viral persistence. These findings suggest PRV7S as a promising oncolytic candidate for myeloid leukaemia, with potential efficacy against CSCs and a favourable safety profile. In conclusion, the study provides new insights into the cellular pathways involved in PRV7S-mediated oncolysis and supports further exploration of PRV7S's potential against resistant leukaemic and solid tumours.

Enhanced apoptosis in damaged laminar tissue of acute laminitis induced by oligofructose overload in dairy cows

Dairy cow laminitis leads to massive financial losses and animal health issues in the worldwide dairy sector. Apoptosis may be an important factor in the epidermal attachment failure. This study explored the laminar tissue apoptotic-related gene and protein status with oligofructose (OF)-induced laminitis in dairy cows. Twelve clinically healthy, non-pregnant Chinese Holstein cows were randomly divided into two groups of six cows each: the control group and the oligofructose overload group (OF group), respectively. At 0 h, 17 g/kg BW of OF dissolved in 20 mL/kg BW of warm deionized water was gavaged to the OF dairy cows through a stomach tube, while the control cows were given the same dose of deionized water in the same way. After 72 h, laminar tissue samples in both groups were collected to express genes and proteins. Compared with the control cows, the gene expression of Bcl2 significantly reduced in the OF cows laminar tissue. The gene expression of Bax and P53 significantly enhanced in the laminar tissue of OF cows compared to the control cows. The expression of Bcl2 protein significantly decreased, whereas the expression of Bax and Bif1, caspase3, caspase8, and caspase9/9p proteins significantly increased in the OF cows' laminar tissues than in the control cows. However, the distribution of Bax and P53 proteins significantly enhanced in the OF cows' laminar tissues relative to the control cows. In conclusion, imbalanced gene and protein status may represent the primary cause of the epidermal attachment failure, which confirmed the increased apoptosis in laminar tissue of sick cows.

Understanding Merkel Cell Carcinoma: Pathogenic Signaling, Extracellular Matrix Dynamics, and Novel Treatment Approaches

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer, driven by either Merkel cell polyomavirus (MCPyV) integration or ultraviolet (UV)-induced mutations. In MCPyV-positive tumors, viral T antigens inactivate tumor suppressors pRb and p53, while virus-negative MCCs harbor UV-induced mutations that activate similar oncogenic pathways. Key signaling cascades, including PI3K/AKT/mTOR and MAPK, support tumor proliferation, survival, and resistance to apoptosis. Histologically, MCC consists of small round blue cells with neuroendocrine features, high mitotic rate, and necrosis. The tumor microenvironment (TME) plays a central role in disease progression and immune escape. It comprises a mix of tumor-associated macrophages, regulatory and cytotoxic T cells, and elevated expression of immune checkpoint molecules such as PD-L1, contributing to an immunosuppressive niche. The extracellular matrix (ECM) within the TME is rich in proteoglycans, collagens, and matrix metalloproteinases (MMPs), facilitating tumor cell adhesion, invasion, and interaction with stromal and immune cells. ECM remodeling and integrin-mediated signaling further promote immune evasion and therapy resistance. Although immune checkpoint inhibitors targeting PD-1/PD-L1 have shown promise in treating MCC, resistance remains a major hurdle. Therapeutic strategies that concurrently target the TME-through inhibition of ECM components, MMPs, or integrin signaling-may enhance immune responses and improve clinical outcomes.

Involvement of the ubiquitin-proteasome system in the regulation of the tumor microenvironment and progression

The tumor microenvironment is a complex environment comprising tumor cells, non-tumor cells, and other critical non-cellular components. Some studies about tumor microenvironment have recently achieved remarkable progress in tumor treatment. As a substantial part of post-translational protein modification, ubiquitination is a crucial player in maintaining protein stability in cell signaling, cell growth, and a series of cellular life activities, which are also essential for regulating tumor cells or other non-tumor cells in the tumor microenvironment. This review focuses on the role and function of ubiquitination and deubiquitination modification in the tumor microenvironment while discussing the prospect of developing inhibitors targeting ubiquity-related enzymes, thereby providing ideas for future research in cancer therapy.

Tonabersat enhances temozolomide-mediated cytotoxicity in glioblastoma by disrupting intercellular connectivity through connexin 43 inhibition

Glioblastoma cells rely on connexin 43 (Cx43)-based gap junctions (GJs) for intercellular communication, enabling them to integrate into a widely branched malignant network. Although there are promising prospects for new targeted therapies, the lack of clinically feasible GJ inhibitors has impeded their adoption in clinical practice. In the present study, we investigated tonabersat (TO), a blood-brain-barrier-penetrating drug with GJ-inhibitory properties, in regard to its potential to disassemble intercellular connectivity in glioblastoma networks. Fluorescence-guided measurements of calcein cell-to-cell transfer were used to study functional intercellular connectivity. Specific DNA fragmentation rates of propidium iodide-stained nuclei were measured as a surrogate readout for cell death using flow cytometry. CRISPR/Cas9-mediated gene editing of Cx43 served as a validation tool of cellular effects related to Cx43 GJ inhibition. 3' mRNA sequencing was performed for molecular downstream analysis. We found that TO reduced intercellular GJ-mediated cytosolic traffic and yielded a significant reduction of tumor microtube (TM) length. TO-mediated inhibition of cellular tumor networks was accompanied by a synergistic effect for temozolomide-induced cell death. CRISPR/Cas9 Cx43-knockout revealed similar results, indicating that TO-mediated inhibitory effects rely on the inhibition of Cx43-based GJs. Gene set enrichment analyses found that GJ-mediated synergistic cytotoxic effects were linked to a significant upregulation of cell death signaling pathways. In conclusion, TO disrupts TM-based network connectivity via GJ inhibition and renders glioblastoma cells more susceptible to cytotoxic therapy. Given its previous use in clinical trials for migraine therapy, TO might harbor the potential of bridging the idea of a GJ-targeted therapeutic approach from bench to bedside.

Wip1 phosphatase activator QGC-8-52 specifically sensitizes p53-negative cancer cells to chemotherapy while protecting normal cells

PP2C serine-threonine phosphatase Wip1 plays an important role in normal tissue homeostasis, stress signaling and pathogenesis of various human diseases. It is an attractive drug target for cancer treatment and inhibition of its expression or activity constitute a novel therapeutic intervention strategy to prevent the development of various cancers. However, previous strategies for Wip1 suppression may be ineffective in cancers lacking p53. Here, we have characterized the activity of a novel Wip1 phosphatase activator, QGC-8-52, in preclinical models of breast malignancies. QGC-8-52 significantly sensitizes the cancer cell lines with p53 deletion to chemotherapeutic agents. This effect was mediated by the Wip1-FOXO3a interaction and subsequent dephosphorylation of Thr487 that resulted, in response to anticancer treatment, in enhancing the transcription activity of FOXO3a on the proapoptotic TRAIL gene. The sensitizing effect of Wip1 activation on chemotherapeutic drugs only targeted cancer cells lacking p53. The activation of Wip1 in normal cells provided protection from anticancer drug-induced apoptosis by reducing the strength of upstream signaling to p53. Therefore, during the treatment of anticancer drugs, the activated Wip1 phosphatase boosts the apoptosis of p53-negative tumors and protects normal tissues. Our findings may represent an effective and safe therapeutic strategy for cancers with p53 deletion.

Exploiting the Anticancer, Antimicrobial and Antiviral Potential of Naphthoquinone Derivatives: Recent Advances and Future Prospects

Cancer remains a primary cause of mortality, with over 18.1 million new cases and 9.6 million deaths globally in 2018. Chemotherapy, which utilizes a spectrum of cytotoxic drugs targeting the rapidly dividing cancer cells, is a predominant treatment modality. However, the tendency of chemotherapeutics to induce drug resistance and exhibit non-specific cytotoxicity necessitates the development of new anticancer agents with heightened efficacy and minimized toxicity. In recent years, the discovery of safe and effective antibacterial/antiviral agents has also been a hot spot in medicinal chemistry. This paper comprehensively reviews the synthesis, anticancer/antibacterial/antiviral activity, and structure-activity relationships of natural 1,4-naphthoquinones and their derivatives. It highlights their potential as efficient and low-toxicity antitumor and anti-infectious drug candidates.

Celastrol promotes DNA damage and apoptosis in uterine corpus endometrial carcinoma via promotion of KAT2B-mediated RBPJ acetylation and repression of MCM4 transcription

BACKGROUND

Uterine corpus endometrial carcinoma (UCEC) is one of the most frequent female genital malignant tumors. Targeting DNA damage and cell apoptosis are regarded as effective ways for UCEC therapy. Celastrol is a natural anti-cancer product from the Celastraceae plant family, while its role in UCEC has not been investigated.

METHODS

UCEC cell lines Ishikawa and HEC-1-A were applied and treated with different concentrations of Celastrol. The appropriate and nontoxic concentrations were used for the subsequent experiments. Functional experiments analyzed the cell viability, cell cycle distribution, DNA damage, apoptosis and the expression of related proteins. We determined tumor growth in xenograft nude mice. Bioinformatic analysis, protein coimmunoprecipitation (Co-IP), luciferase assay, cell experiments were performed to reveal the relationship of Celastrol/KAT2B/RBPJ/MCM4 in UCEC.

RESULTS

Treatment of Celastrol inhibited cell viability in a dose-dependent manner, and caused cell cycle arrest, accompanied by the downregulation of CDK2 and cyclin E expression and the upregulation of p21. Celastrol treatment resulted DNA damage and apoptosis in cultured cells, as demonstrated by increased number of TUNEL-positive cells, activity of caspase-3 and expression of cleaved-caspase-9, cleaved PARP1 and γ-H2AX. In xenograft nude mice, Celastrol also repressed tumor growth. Furthermore, lysine acetyltransferase KAT2B was a putative target of Celastrol, and its expression was upregulated by Celastrol in vitro and in vivo. Overexpression of KAT2B in UCEC inhibited cell proliferation and increased DNA damage and apoptosis. KAT2B knockdown overcame the anti-proliferative and pro-apoptotic roles of Celastrol. Moreover, Co-IP demonstrated that KAT2B bound to RBPJ, a transcriptional repressor, and increased the acetylation of RBPJ. RBPJ could bind to the MCM4 promoter to suppress the luciferase activity. Further functional analysis revealed that the functions of KAT2B in UCEC cell proliferation, DNA damage and apoptosis were mediated by MCM4, and Celastrol enhanced RBPJ acetylation and reduced MCM4 expression.

CONCLUSIONS

These results underscore that Celastrol is a promising anti-cancer agent in UCEC with preferential anti-proliferative, pro-apoptotic and DNA damage effects through the KAT2B/RBPJ/MCM4 axis, and KAT2B is a promising therapeutic target for UCEC.

Harnessing p53 for targeted cancer therapy: new advances and future directions

The transcription factor p53 is the most frequently impaired tumor suppressor in human cancers. In response to various stress stimuli, p53 activates transcription of genes that mediate its tumor-suppressive functions. Distinctive characteristics of p53 outlined here enable a well-defined program of genes involved in cell cycle arrest, apoptosis, senescence, differentiation, metabolism, autophagy, DNA repair, anti-viral response, and anti-metastatic functions, as well as facilitating autoregulation within the p53 network. This versatile, anti-cancer network governed chiefly by a single protein represents an immense opportunity for targeted cancer treatment, since about half of human tumors retain unmutated p53. During the last two decades, numerous compounds have been developed to block the interaction of p53 with the main negative regulator MDM2. However, small molecule inhibitors of MDM2 only induce a therapeutically desirable apoptotic response in a limited number of cancer types. Moreover, clinical trials of the MDM2 inhibitors as monotherapies have not met expectations and have revealed hematological toxicity as a characteristic adverse effect across this drug class. Currently, combination treatments are the leading strategy for enhancing efficacy and reducing adverse effects of MDM2 inhibitors. This review summarizes efforts to identify and test therapeutics that work synergistically with MDM2 inhibitors. Two main types of drugs have emerged among compounds used in the following combination treatments: first, modulators of the p53-regulated transcriptome (including chromatin modifiers), translatome, and proteome, and second, drugs targeting the downstream pathways such as apoptosis, cell cycle arrest, DNA repair, metabolic stress response, immune response, ferroptosis, and growth factor signaling. Here, we review the current literature in this field, while also highlighting overarching principles that could guide target selection in future combination treatments.

Nicotinamide: A Multifaceted Molecule in Skin Health and Beyond

Nicotinamide (NAM), the amide form of vitamin B3, is a precursor to essential cofactors nicotinamide adenine dinucleotide (NAD⁺) and NADPH. NAD⁺ is integral to numerous cellular processes, including metabolism regulation, ATP production, mitochondrial respiration, reactive oxygen species (ROS) management, DNA repair, cellular senescence, and aging. NAM supplementation has demonstrated efficacy in restoring cellular energy, repairing DNA damage, and inhibiting inflammation by suppressing pro-inflammatory cytokines release. Due to its natural presence in a variety of foods and its excellent safety profile-even at high doses of up to 3 g/day-NAM is extensively used in the chemoprevention of non-melanoma skin cancers and the treatment of dermatological conditions such as blistering diseases, atopic dermatitis, rosacea, and acne vulgaris. Recently, its anti-aging properties have elevated NAM's prominence in skincare formulations. Beyond DNA repair and energy replenishment, NAM significantly impacts oxidative stress reduction, cell cycle regulation, and apoptosis modulation. Despite these multifaceted benefits, the comprehensive molecular mechanisms underlying NAM's actions remain not fully elucidated. This review consolidates recent research to shed light on these mechanisms, emphasizing the critical role of NAM in cellular health and its therapeutic potential. By enhancing our understanding, this work underscores the importance of continued exploration into NAM's applications, aiming to inform future clinical practices and skincare innovations.

The underlying mechanisms of the association of bone health with depression - an experimental study

BACKGROUND

Depression constitutes a risk factor for osteoporosis, but underlying molecular and cellular mechanisms are not fully understood. MiRNAs influence gene expression and are carried by extracellular vesicles (EV), affecting cell-cell communication.

AIMS

(1) Identify the difference in miRNA expression between depressed patients and healthy controls; (2) Analyze associations of these miRNAs with bone turnover markers; (3) Analyze target genes of differentially regulated miRNAs and predict associated pathways regarding depression and bone metabolism.

METHODS AND RESULTS

Blood samples from depressed patients (n = 11) were obtained from a previous study and healthy controls (n = 9) were recruited. Sociodemographic, depression diagnosis and depressive symptom (BDI-II) data were collected through questionnaires. Blood plasma was collected from each participant and real-time-quantitative PCR was performed on isolated plasma EVs; differences in miRNA expression between groups were analyzed using qbase+. Regression models assessed the associations of differentially regulated miRNAs with bone turnover markers procollagen-1 N-terminal-peptide, osteocalcin, and crosslaps; enriched pathways and miRNA target gene networks were analyzed. 19 miRNAs were differentially expressed between groups (p < 0.05). MiR-26b-5p and miR-106a-5p showed an association with procollagen-1 N-terminal-peptide; miR-330-5p and miR-377-3p were associated with osteocalcin, and miR-26b-5p, miR-34c-3p and miR-145 with crosslaps. Pathway analysis including the differentially expressed miRNAs predicted enriched pathways, including the FoxO signaling and p53 signaling pathway. Seven target genes were identified.

CONCLUSIONS

MiRNAs (e.g. miR-26b-5p, miR-377-3p), genes (TNRC6B, HSPA8), and pathways (FoxO- and Hippo-signaling pathway) are identified which could be mediators between the influence of depression on bone health and could possibly serve as biomarkers in the treatment of bone diseases among people with mental disorders.

Discovery of Rezatapopt (PC14586), a First-in-Class, Small-Molecule Reactivator of p53 Y220C Mutant in Development

p53 is a potent transcription factor that is crucial in regulating cellular responses to stress. Mutations in the TP53 gene are found in >50% of human cancers, predominantly occurring in the DNA-binding domain (amino acids 94-292). The Y220C mutation accounts for 1.8% of all of the TP53 mutations and produces a thermally unstable protein. Rezatapopt (also known as PC14586) is the first small-molecule p53 Y220C reactivator being evaluated in clinical trials. Rezatapopt was specifically designed to tightly bind to a pocket created by the TP53 Y220C mutation. By stabilization of the p53 protein structure, rezatapopt restores p53 tumor suppressor functions. In mouse models with established human tumor xenografts harboring the TP53 Y220C mutation, rezatapopt demonstrated tumor inhibition and regression at well-tolerated doses. In Phase 1 clinical trials, rezatapopt demonstrated a favorable safety profile within the efficacious dose range and showed single-agent efficacy in heavily pretreated patients with various TP53 Y220C mutant solid tumors.

Anticancer Potential of Pineapple and its Bioactive Compound Bromelain

Various ailments have been treated with pineapple (Ananas comosus (L.) Merr.) throughout medicinal history. Pineapple and its bioactive compound bromelain possess health-promoting benefits. Detailed information on the chemotherapeutic activities of pineapple and its bioactive compound bromelain is provided in this review, which analyses the current literature regarding their therapeutic potential in cancer. Research on disease models in cell cultures is the focus of much of the existing research. Several studies have demonstrated the benefits of pineapple extract and bromelain for in vitro and in vivo cancer models. Preliminary animal model results show promise, but they must be translated into the clinical setting. Research on these compounds represents a promising future direction and may be well-tolerated.

The importance of TP53 status in cancer therapy: The example of chronic lymphocytic leukemia

The TP53 gene encodes the tumor suppressor protein p53, which plays a critical role in genomic stability and cell cycle regulation. TP53 mutations are prevalent in approximately half of all human malignancies and are associated with poor clinical outcomes, including increased genomic instability, chemoresistance, and reduced survival rates. However, the prognostic and predictive value of TP53 status remains inconsistent across cancer types. Chronic lymphocytic leukemia (CLL) stands out as a disease where TP53 alterations have a well-established clinical significance, influencing treatment decisions and patient prognosis. In CLL, TP53 mutations and 17p deletions are strongly correlated with advanced disease stages, resistance to chemo-immunotherapy, and poor overall survival. The European Research Initiative for CLL (ERIC) has recognized TP53 status as a crucial prognostic biomarker, advocating for its routine assessment in clinical practice. Given the limitations of traditional therapies in TP53-mutated CLL, novel targeted therapies, including BCL2 and BTK inhibitors, as well as CAR-T cell therapy, are being explored to improve patient outcomes. This review provides an in-depth analysis of the evolving role of TP53 status in CLL, with a particular focus on emerging therapeutic strategies, including CAR-T cell therapy, and their potential to overcome TP53-driven treatment resistance.

Differentially expressed miRNA profiles of serum derived extracellular vesicles from patients with acute ischemic stroke

BACKGROUND

MicroRNAs (miRNAs) participate in diverse cellular changes following acute ischemic stroke (AIS). Circulating miRNAs, stabilized and delivered to target cells via extracellular vesicles (EVs), are potential biomarkers to facilitate diagnosis, prognosis, and therapeutic modulation. We aimed to identify distinctive expression patterns of circulating EV-miRNAs in AIS patients.

METHODS

miRNA profiles from EVs, isolated from plasma samples collected within 24 h following AIS diagnosis, were examined between a dataset of 10 age-, gender- and existing comorbidities-matched subjects (5 AIS and 5 healthy controls, HC). We measured 2578 miRNAs and identified differentially expressed miRNAs between AIS and HC. An enrichment analysis was conducted to delineate the networks and biological pathways implicated by differentially expressed microRNAs. An enrichment analysis was conducted to delineate the networks and biological pathways implicated by differentially expressed microRNAs.

RESULTS

Five miRNAs were differentially expressed between stroke (AIS) versus control (HC). hsa-let-7b-5p, hsa-miR-16-5p, and hsa-miR-320c were upregulated, whereas hsa-miR-548a-3p and hsa-miR-6808-3p, with no previously reported changes in stroke were downregulated. The target genes of these miRNAs affect various cellular pathways including, RNA transport, autophagy, cell cycle progression, cellular senescence, and signaling pathways like mTOR, PI3K-Akt, and p53. Key hub genes within these networks include TP53, BCL2, Akt, CCND1, and NF-κB. These pathways are crucial for cellular function and stress response, and their dysregulation can have significant implications for the disease processes.

CONCLUSION

Our findings reveal distinct circulating EV-miRNA expression patterns in AIS patients from Qatar, highlighting potential biomarkers that could aid in stroke diagnosis and therapeutic strategies. The identified miRNAs are involved in critical cellular pathways, offering novel insights into the molecular mechanisms underlying stroke pathology. Circulating EV-miRNAs differentially expressed in AIS may have a pathophysiological role and may guide further research to elucidate their precise mechanisms.

Nucleo-cytoplasmic environment modulates spatiotemporal p53 phase separation

Liquid-liquid phase separation of various transcription factors into biomolecular condensates plays an essential role in gene regulation. Here, using cellular models and in vitro studies, we show the spatiotemporal formation and material properties of p53 condensates that might dictate its function. In particular, p53 forms liquid-like condensates in the nucleus of cells, which can bind to DNA and perform transcriptional activity. However, cancer-associated mutations promote misfolding and partially rigidify the p53 condensates with impaired DNA binding ability. Irrespective of wild-type and mutant forms, the partitioning of p53 into cytoplasm leads to the condensate formation, which subsequently undergoes rapid solidification. In vitro studies show that abundant nuclear components such as RNA and nonspecific DNA promote multicomponent phase separation of the p53 core domain and maintain their liquid-like property, whereas specific DNA promotes its dissolution into tetrameric functional p53. This work provides mechanistic insights into how the life cycle and DNA binding properties of p53 might be regulated by phase separation.

Alternative isoforms and phase separation of Ref1 repress morphogenesis in Cryptococcus

Cryptococcus neoformans, the causative agent of cryptococcosis and a representative of the Basidiomycota phylum of Fungi, is a valuable model for our understanding of eukaryotic/fungal biology. Negative feedback is a well-documented mechanism across Eukarya to regulate developmental transitions. Here, we describe a repressor of the yeast-to-hypha transition, Ref1, which completes a negative feedback loop driven by the master regulator of hyphal morphogenesis, Znf2, during sexual development. Alternative transcription of Ref1, driven by Znf2, produces a functionally distinct Ref1 isoform. Isoform-specific capacity for phase separation imparts this functional distinction, making Ref1 a stronger repressor and more vulnerable to proteolytic degradation. The multimodal nature of Ref1 provides versatility that allows cells to fine-tune Ref1 activity to suit developmental context. This work reveals a mechanism by which phase separation allows a transcriptional program to tailor its own repression to guide an organism through morphological transition.

Interaction of p53 with the Δ133p53α and Δ160p53α isoforms regulates p53 conformation and transcriptional activity

The TP53 gene encodes p53, a transcription factor involved in tumor suppression. However, TP53 also encodes other protein isoforms, some of which can disrupt the tumor suppressor functions of p53 even in the absence of TP53 mutations. In particular, elevated levels of the Δ133TP53 mRNA are detected in many cancer types and can be associated with poorer disease-free survival. We investigated the mechanisms of action of the two proteins translated from the Δ133TP53 mRNA: the Δ133p53α and Δ160p53α isoforms, both of which retain the oligomerization domain of p53. We discovered that the Δ133p53α and Δ160p53α isoforms adopt an altered conformation compared to full-length p53, exposing the PAb240 epitope (RHSVVV), which is inaccessible to the PAb240 antibody in the functional conformation of p53 (reactive to PAb1620). The Δ133p53α and/or Δ160p53α isoforms form hetero-oligomers with p53, regulating the stability, the conformation and the transcriptional activity of the p53 hetero-oligomers. Under basal conditions, Δ133p53α and Δ160p53α, in complex with p53, prevent proteasome-dependent degradation leading to the accumulation of PAb240 reactive Δ133p53α/Δ160p53α/p53 hetero-oligomers without increasing p53 transcriptional activity. Conversely, depletion of endogenous Δ133p53α isoforms in human fibroblasts is sufficient to restore p53 transcriptional activity, towards p53-target genes involved in cell cycle arrest. In the DNA damage response (DDR), PAb240 reactive Δ133p53α/Δ160p53α/p53 hetero-oligomers are highly phosphorylated at Ser15 compared to PAb1620-reactive p53 complexes devoid of Δ133p53α and Δ160p53α. This suggests that PAb240-reactive p53 hetero-oligomers integrate DNA damage signals. Δ133p53α accumulation is a late event in the DDR that depends on p53, but not on its transcriptional activation. The formation of Δ133p53α and p53 complexes increases at later DDR stages. We propose that Δ133p53α isoforms regulate p53 conformation as part of the normal p53 biology, modulating p53 activity and thereby adapting the cellular response to the cell signals.

Gene regulatory network inference from CRISPR perturbations in primary CD4+ T cells elucidates the genomic basis of immune disease

The effects of genetic variation on complex traits act mainly through changes in gene regulation. Although many genetic variants have been linked to target genes in cis, the trans-regulatory cascade mediating their effects remains largely uncharacterized. Mapping trans-regulators based on natural genetic variation has been challenging due to small effects, but experimental perturbations offer a complementary approach. Using CRISPR, we knocked out 84 genes in primary CD4+ T cells, targeting inborn error of immunity (IEI) disease transcription factors (TFs) and TFs without immune disease association. We developed a novel gene network inference method called linear latent causal Bayes (LLCB) to estimate the network from perturbation data and observed 211 regulatory connections between genes. We characterized programs affected by the TFs, which we associated with immune genome-wide association study (GWAS) genes, finding that JAK-STAT family members are regulated by KMT2A, an epigenetic regulator. These analyses reveal the trans-regulatory cascades linking GWAS genes to signaling pathways.

Targeted protein degradation: advances in drug discovery and clinical practice

Targeted protein degradation (TPD) represents a revolutionary therapeutic strategy in disease management, providing a stark contrast to traditional therapeutic approaches like small molecule inhibitors that primarily focus on inhibiting protein function. This advanced technology capitalizes on the cell's intrinsic proteolytic systems, including the proteasome and lysosomal pathways, to selectively eliminate disease-causing proteins. TPD not only enhances the efficacy of treatments but also expands the scope of protein degradation applications. Despite its considerable potential, TPD faces challenges related to the properties of the drugs and their rational design. This review thoroughly explores the mechanisms and clinical advancements of TPD, from its initial conceptualization to practical implementation, with a particular focus on proteolysis-targeting chimeras and molecular glues. In addition, the review delves into emerging technologies and methodologies aimed at addressing these challenges and enhancing therapeutic efficacy. We also discuss the significant clinical trials and highlight the promising therapeutic outcomes associated with TPD drugs, illustrating their potential to transform the treatment landscape. Furthermore, the review considers the benefits of combining TPD with other therapies to enhance overall treatment effectiveness and overcome drug resistance. The future directions of TPD applications are also explored, presenting an optimistic perspective on further innovations. By offering a comprehensive overview of the current innovations and the challenges faced, this review assesses the transformative potential of TPD in revolutionizing drug development and disease management, setting the stage for a new era in medical therapy.

The crosstalk of Wnt/β-catenin signaling and p53 in acute kidney injury and chronic kidney disease

Wnt/β-catenin is a signaling pathway associated with embryonic development, organ formation, cancer, and fibrosis. Its activation can repair kidney damage during acute kidney injury (AKI) and accelerate the occurrence of renal fibrosis after chronic kidney disease (CKD). Interestingly, p53 has also been found as a key modulator in AKI and CKD in recent years. Meantime, some studies have found crosstalk between Wnt/β-catenin signaling pathways and p53, but more evidence is required on whether they have synergistic effects in renal disease progression. This article reviews the role and therapeutic targets of Wnt/β-catenin and p53 in AKI and CKD and proposes for the first time that Wnt/β-catenin and p53 have a synergistic effect in the treatment of renal injury.

Cellular senescence and its pathogenic and therapeutic implications in autoimmune hepatitis

INTRODUCTION

Senescent cells are characterized by replicative arrest and phenotypes that produce diverse pro-inflammatory and pro-oxidant mediators. The senescence of diverse hepatic cell types could constitute an unrecognized pathogenic mechanism and prognostic determinant in autoimmune hepatitis. The impact of cellular senescence in autoimmune hepatitis is unknown, and it may suggest adjunctive management strategies.

AREAS COVERED

This review describes the molecular mechanisms of cellular senescence, indicates its diagnostic features, suggests its consequences, presents possible therapeutic interventions, and encourages investigations of its pathogenic role and management in autoimmune hepatitis. Treatment prospects include elimination or reversal of senescent cells, generation of ectopic telomerase, reactivation of dormant telomerase, neutralization of specific pro-inflammatory secretory products, and mitigation of the effects of mitochondrial dysfunction.

EXPERT OPINION

The occurrence, nature, and consequences of cellular senescence in autoimmune hepatitis must be determined. The senescence of diverse hepatic cell types could affect the outcome of autoimmune hepatitis by impairing hepatic regeneration, intensifying liver inflammation, and worsening hepatic fibrosis. Cellular senescence could contribute to suboptimal responses during conventional glucocorticoid-based therapy. Interventions that target specific pro-inflammatory products of the senescent phenotype or selectively promote apoptosis of senescent cells may be preferred adjunctive treatments for autoimmune hepatitis depending on the cancer risk.

Protein profile at newly restored implants compared to contralateral teeth over 12-months: a pilot study

OBJECTIVES

To determine crevicular fluid alterations in protein expression of newly restored implants during their first year of function and associate them with those of contralateral teeth.

MATERIALS AND METHODS

In ten non-smokers, successfully treated for periodontitis, one newly restored implant (baseline-T0) and one corresponding tooth were followed for 12-months (T1). Oral hygiene was monitored during the study. Periodontal clinical indices and crevicular fluid were collected from an implant-site (PICF) and a tooth-site (GCF). Total proteomic profiles of PICF and GCF were investigated using label-free quantitative proteomics.

RESULTS

Clinical recordings remained stable at 12-months on the tooth-/implant-site basis. The comparative analysis of protein enrichment between teeth and implants at T0 revealed 664 human proteins, with 93 found only in teeth and 217 exclusively in implants. Among the 354 overlapping proteins, 46 were upregulated (log2FC > 1) in teeth, while 61 in implants. At T1, 569 human proteins were exclusively identified, with 67 found only in teeth and 193 exclusively in implants. Of the 309 overlapping proteins, 22 were upregulated in teeth, while 48 were in implants. The over-representation enrichment analysis identified "interferon-alpha response" and "allograft rejection" pathways, as significantly regulated categories at T0, with the latter being over-represented at T1.

CONCLUSIONS

Peri-implant tissue maturation was evident during the study. Proteins expressed in crevicular fluid reflected unique patterns between implants and teeth that are worth studying.

CLINICAL RELEVANCE

Different proteomic patterns were observed at the implant-site compared to the contralateral tooth-site towards inflammatory processes that prevail within otherwise clinically healthy peri-implant tissues.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID: NCT06379022.

Predicting p53-dependent cell transitions from thermodynamic models

A cell's fate involves transitions among its various states, each defined by a distinct gene expression profile governed by the topology of gene regulatory networks, which are affected by 3D genome organization. Here, we develop thermodynamic models to determine the fate of a malignant cell as governed by the tumor suppressor p53 signaling network, taking into account long-range chromatin interactions in the mean-field approximation. The tumor suppressor p53 responds to stress by selectively triggering one of the potential transcription programs that influence many layers of cell signaling. These range from p53 phosphorylation to modulation of its DNA binding affinity, phase separation phenomena, and internal connectivity among cell fate genes. We use the minimum free energy of the system as a fundamental property of biological networks that influences the connection between the gene network topology and the state of the cell. We constructed models based on network topology and equilibrium thermodynamics. Our modeling shows that the binding of phosphorylated p53 to promoters of target genes can have properties of a first order phase transition. We apply our model to cancer cell lines ranging from breast cancer (MCF-7), colon cancer (HCT116), and leukemia (K562), with each one characterized by a specific network topology that determines the cell fate. Our results clarify the biological relevance of these mechanisms and suggest that they represent flexible network designs for switching between developmental decisions.

Molecular Imaging of p53 in Mouse Models of Cancer Using a Radiolabeled Antibody TAT Conjugate with SPECT

Mutations of p53 protein occur in over half of all cancers, with profound effects on tumor biology. We present the first-to our knowledge-method for noninvasive visualization of p53 in tumor tissue in vivo, using SPECT, in 3 different models of cancer. Methods: Anti-p53 monoclonal antibodies were conjugated to the cell-penetrating transactivator of transcription (TAT) peptide and a metal ion chelator and then radiolabeled with 111In to allow SPECT imaging. 111In-anti-p53-TAT conjugates were retained longer in cells overexpressing p53-specific than non-p53-specific 111In-mIgG (mouse IgG from murine plasma)-TAT controls, but not in null p53 cells. Results: In vivo SPECT imaging showed enhanced uptake of 111In-anti-p53-TAT, versus 111In-mIgG-TAT, in high-expression p53R175H and medium-expression wild-type p53 but not in null p53 tumor xenografts. The results were confirmed in mice bearing genetically engineered KPC mouse-derived pancreatic ductal adenocarcinoma tumors. Imaging with 111In-anti-p53-TAT was possible in KPC mice bearing spontaneous p53R172H pancreatic ductal adenocarcinoma tumors. Conclusion: We demonstrate the feasibility of noninvasive in vivo molecular imaging of p53 in tumor tissue using a radiolabeled TAT-modified monoclonal antibody.

Gliomedin drives gastric cancer cell proliferation and migration, correlating with a poor prognosis

Gastric cancer (GC) is a prevalent global malignancy, often diagnosed at advanced stage due to a lack of early symptoms and reliable markers. Previous research has identified gliomedin (GLDN) as a potential predictive marker for poor prognosis in cancer patients. However, the specific relationship between GLDN expression and GC prognosis has been unclear. Using the Tumor-Immune System Interaction Database (TISIDB), we examined GLDN expression in GC tissues and found a positive correlation with advanced clinical stages. Kaplan-Meier Plotter analysis further demonstrated that elevated GLDN levels were closely associated with poor prognosis in GC patients. To explore the functional significance of GLDN in GC, we conducted experiments involving GLDN overexpression and knockdown in GC cell lines, as well as subcutaneous tumor formation in nude mice. Our findings provided compelling evidence that GLDN promotes GC cell proliferation, viability, and migration, significantly enhancing tumor growth in vivo. Mechanistically, RNA-sequencing (RNA-seq) combined with bioinformatics analysis revealed that GLDN influences genes enriched in the p53 signaling pathway. Our data suggest that GLDN likely regulates cell proliferation through the p53-p21-CyclinD/CDK4 signaling axis. In conclusion, our study underscores GLDN's critical role in regulating GC cell proliferation and migration, and proposes its potential as a prognostic marker for GC patients.

Hepatitis B Virus X Protein Induces Reactive Oxygen Species Generation via Activation of p53 in Human Hepatoma Cells

Hepatitis B virus (HBV), particularly through the HBx protein, induces oxidative stress during liver infections. This study reveals that HBx increases reactive oxygen species (ROS) via two distinct mechanisms. The first mechanism is p53-independent, likely involving mitochondrial dysfunction, as demonstrated by elevated ROS levels in p53-deficient Hep3B cells and p53-knocked-down HepG2 cells after HBx expression or HBV infection. The increase in ROS persisted even when p53 transcriptional activity was inhibited by pifithrin-α (PFT-α), a p53 inhibitor. The second mechanism is p53-dependent, wherein HBx activates p53, which then amplifies ROS production through a feedback loop involving ROS and p53. The ability of HBx to elevate ROS levels was higher in HepG2 than in Hep3B cells. Knocking down p53 in HepG2 cells lowered ROS levels, while ectopic p53 expression in Hep3B cells raised ROS. HBx-activated p53 downregulated catalase and upregulated manganese-dependent superoxide dismutase, contributing to ROS amplification. The transcriptional activity of p53 was crucial for these effects, as cells with a p53 R175H mutation or those treated with PFT-α generated less ROS. Additionally, HBx variants with Ser-101 increased p53 and ROS levels, whereas variants with Pro-101 did not. These dual mechanisms of HBx-induced ROS generation are likely significant in the pathogenesis of HBV and may contribute to liver diseases, including hepatocellular carcinoma.

Novel circular RNA hsa_circ_0036683 suppresses proliferation and migration by mediating the miR-4664-3p/CDK2AP2 axis in non-small cell lung cancer

BACKGROUND

The aim of the present study was to investigate the function of novel circular RNA hsa_circ_0036683 (circ-36683) in non-small cell lung cancer (NSCLC).

METHODS

RNA sequencing was used to screen out differentially expressed miRNAs. Expression levels of miR-4664-3p and circ-36683 were evaluated in lung carcinoma cells and tissues by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The effects of miR-4664-3p and circ-36683 on proliferation and migration were assessed using cell counting kit-8 (CCK-8), wound healing and transwell migration assays and xenograft experiments. The targeting relationship of circ-36683/miR-4664-3p/CDK2AP2 was assessed by luciferase reporter assays, western blot, qRT-PCR and argonaute2-RNA immunoprecipitation (AGO2 RIP). Co-immunoprecipitation (Co-IP), 5-ethynyl-2'-deoxyuridine (EdU) staining and CCK-8 were used to validate the indispensable role of CDK2AP2 in suppressing cell proliferation as a result of CDK2AP1 overexpression.

RESULTS

By RNA sequencing, miR-4664-3p was screened out as an abnormally elevated miRNA in NSCLC tissues. Transfection of miR-4664-3p could promote cell proliferation, migration and xenograft tumor growth. As a target of miR-4664-3p, CDK2AP2 expression was downregulated by miR-4664-3p transfection and CDK2AP2 overexpression could abolish the proliferation promotion resulting from miR-4664-3p elevation. Circ-36683, derived from back splicing of ABHD2 pre-mRNA, was attenuated in NSCLC tissue and identified as a sponge of miR-4664-3p. The functional study revealed that circ-36683 overexpression suppressed cell proliferation, migration and resulted in G0/G1 phase arrest. More importantly, the antioncogenic function of circ-36683 was largely dependent on the miR-4664-3p/CDK2AP2 axis, through which circ-36683 could upregulate the expression of p53/p21/p27 and downregulate the expression of CDK2/cyclin E1.

CONCLUSION

The present study revealed the antioncogenic role of circ-36683 in suppressing cell proliferation and migration and highlighted that targeting the circ-36683/miR-4664-3p/CDK2AP2 axis is a promising strategy for the intervention of NSCLC.

Transcriptomic and developmental effects of persistent organic pollutants in sentinel fishes collected near an arctic formerly used defense site

Alaska contains over 600 formerly used defense (FUD) sites, many of which serve as point sources of pollution. These sites are often co-located with rural communities that depend upon traditional subsistence foods, especially lipid-rich animals that bioaccumulate and biomagnify persistent organic pollutants (POPs). Many POPs are carcinogenic and endocrine-disrupting compounds that are associated with adverse health outcomes. Therefore, elevated exposure to POPs from point sources of pollution may contribute to disproportionate incidence of disease in arctic communities. We investigated PCB concentrations and the health implications of POP exposure in sentinel fishes collected near the Northeast Cape FUD site on Sivuqaq (St. Lawrence Island), Alaska. Sivuqaq residents are almost exclusively Yupik and rely on subsistence foods. At the request of the Sivuqaq community, we examined differential gene expression and developmental pathologies associated with exposure to POPs originating at the Northeast Cape FUD site. We found significantly higher levels of PCBs in Alaska blackfish (Dallia pectoralis) collected from contaminated sites downstream of the FUD site compared to fish collected from upstream reference sites. We compared transcriptomic profiles and histopathologies of these same blackfish. Blackfish from contaminated sites overexpressed genes involved in ribosomal and FoxO signaling pathways compared to blackfish from reference sites. Contaminated blackfish also had significantly fewer thyroid follicles and smaller pigmented macrophage aggregates. Conversely, we found that ninespine stickleback (Pungitius pungitius) from contaminated sites exhibited thyroid follicle hyperplasia. Despite our previous research reporting transcriptomic and endocrine differences in stickleback from contaminated vs. reference sites, we did not find significant differences in kidney or gonadal histomorphologies. Our results demonstrate that contaminants from the Northeast Cape FUD site are associated with altered gene expression and thyroid development in native fishes. These results are consistent with our prior work demonstrating disruption of the thyroid hormone axis in Sivuqaq residents.

GRK2-mediated AKT activation controls cell cycle progression and G2 checkpoint in a p53-dependent manner

Cell cycle checkpoints, activated by stressful events, halt the cell cycle progression, and prevent the transmission of damaged DNA. These checkpoints prompt cell repair but also trigger cell death if damage persists. Decision-making between these responses is multifactorial and context-dependent, with the tumor suppressor p53 playing a central role. In many tumor cells, p53 alterations lead to G1/S checkpoint loss and the weakening of the G2 checkpoint, rendering cell viability dependent on the strength of the latter through mechanisms not fully characterized. Cells with a strong pro-survival drive can evade cell death despite substantial DNA lesions. Deciphering the integration of survival pathways with p53-dependent and -independent mechanisms governing the G2/M transition is crucial for understanding G2 arrest functionality and predicting tumor cell response to chemotherapy. The serine/threonine kinase GRK2 emerges as a signaling node in cell cycle modulation. In cycling cells, but not in G2 checkpoint-arrested cells, GRK2 protein levels decline during G2/M transition through a process triggered by CDK2-dependent phosphorylation of GRK2 at the S670 residue and Mdm2 ubiquitination. We report now that this downmodulation in G2 prevents the unscheduled activation of the PI3K/AKT pathway, allowing cells to progress into mitosis. Conversely, higher GRK2 levels lead to tyrosine phosphorylation by the kinase c-Abl, promoting the direct association of GRK2 with the p85 regulatory subunit of PI3K and AKT activation in a GRK2 catalytic-independent manner. Hyperactivation of AKT is conditioned by p53's scaffolding function, triggering FOXO3a phosphorylation, impaired Cyclin B1 accumulation, and CDK1 activation, causing a G2/M transition delay. Upon G2 checkpoint activation, GRK2 potentiates early arrest independently of p53 through AKT activation. However, its ability to overcome the G2 checkpoint in viable conditions depends on p53. Our results suggest that integrating the GRK2/PI3K/AKT axis with non-canonical functions of p53 might confer a survival advantage to tumor cells.

Integrative RNA-seq and ChIP-seq analysis unveils metabolic regulation as a conserved antiviral mechanism of chicken p53

The tumor suppressor p53, primarily functioning as a transcription factor, has exhibited antiviral capabilities against various viruses in chickens, including infectious bursal disease virus (IBDV), avian leukosis virus subgroup J (ALV-J), and avian infectious laryngotracheitis virus (ILTV). Nevertheless, the existence of a universal antiviral mechanism employed by chicken p53 (chp53) against these viruses remains uncertain. This study conducted a comprehensive comparison of molecular networks involved in chp53's antiviral function against IBDV, ALV-J, and ILTV. This was achieved through an integrated analysis of ChIP-seq data, examining chp53's genome-wide chromatin occupancy, and RNA-seq data from chicken cells infected with these viruses. The consistent observation of chp53 target gene enrichment in metabolic pathways, confirmed via ChIP-qPCR, suggests a ubiquitous regulation of host cellular metabolism by chp53 across different viruses. Further genome binding motif conservation analysis and transcriptional co-factor prediction suggest conserved transcriptional regulation mechanism by which chp53 regulates host cellular metabolism during viral infection. These findings offer novel insights into the antiviral role of chp53 and propose that targeting the virus-host metabolic interaction through regulating p53 could serve as a universal strategy for antiviral therapies in chickens.IMPORTANCEThe current study conducted a comprehensive analysis, comparing molecular networks underlying chp53's antiviral role against infectious bursal disease virus (IBDV), avian leukosis virus subgroup J (ALV-J), and avian infectious laryngotracheitis virus (ILTV). This was achieved through a combined assessment of ChIP-seq and RNA-seq data obtained from infected chicken cells. Notably, enrichment of chp53 target genes in metabolic pathways was consistently observed across viral infections, indicating a universal role of chp53 in regulating cellular metabolism during diverse viral infections. These findings offer novel insights into the antiviral capabilities of chicken p53, laying a foundation for the potential development of broad-spectrum antiviral therapies in chickens.

A first-in-human phase I study of a novel MDM2/p53 inhibitor alrizomadlin in advanced solid tumors

BACKGROUND

The mouse double minute 2 homolog (MDM2) oncogene exerts oncogenic activities in many cancers and represents a potential therapeutic target. This trial evaluated the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of alrizomadlin (APG-115), a novel MDM2/p53 inhibitor, in patients with advanced solid tumors.

PATIENTS AND METHODS

Patients with histologically confirmed advanced solid tumors who had progressed to standard treatment or lacked effective therapies were recruited. Alrizomadlin was administered once daily every other day for 21 days of a 28-day cycle until disease progression or intolerable toxicity.

RESULTS

A total of 21 patients were enrolled and treated with alrizomadlin; 57.1% were male and the median age was 47 (25-60) years. The maximum tolerated dose of alrizomadlin was 150 mg and the recommended phase II dose was 100 mg. One patient in the 200-mg cohort experienced dose-limiting toxicity of thrombocytopenia and febrile neutropenia. The most common grade 3/4 treatment-related adverse events were thrombocytopenia (33.3%), lymphocytopenia (33.3%), neutropenia (23.8%), and anemia (23.8%). Alrizomadlin demonstrated approximately linear pharmacokinetics (dose range 100-200 mg) and was associated with increased plasma macrophage inhibitory cytokine-1, indicative of p53 pathway activation. Of the 20 assessable patients, 2 [10%, 95% confidence interval (CI) 1.2% to 31.7%] patients achieved partial response and 10 (50%, 95% CI 27.2% to 72.8%) showed stable disease. The median progression-free survival was 6.1 (95% CI 1.7-10.4) months, which was significantly longer in patients with wild-type versus mutant TP53 (7.9 versus 2.2 months, respectively; P < 0.001). Among patients with MDM2 amplification and wild-type TP53, the overall response rate was 25% (2/8) and the disease control rate was 100% (8/8).

CONCLUSIONS

Alrizomadlin had an acceptable safety profile and demonstrated promising antitumor activity in MDM2-amplified and TP53 wild-type tumors. This study supports further exploration of alrizomadlin with recommended doses of 100 mg q.o.d. in 21 days on and 7 days off regimen.

ARTS and small-molecule ARTS mimetics upregulate p53 levels by promoting the degradation of XIAP

Mutations resulting in decreased activity of p53 tumor suppressor protein promote tumorigenesis. P53 protein levels are tightly regulated through the Ubiquitin Proteasome System (UPS). Several E3 ligases were shown to regulate p53 stability, including MDM2. Here we report that the ubiquitin E3 ligase XIAP (X-linked Inhibitors of Apoptosis) is a direct ligase for p53 and describe a novel approach for modulating the levels of p53 by targeting the XIAP pathway. Using in vivo (live-cell) and in vitro (cell-free reconstituted system) ubiquitylation assays, we show that the XIAP-antagonist ARTS regulates the levels of p53 by promoting the degradation of XIAP. XIAP directly binds and ubiquitylates p53. In apoptotic cells, ARTS inhibits the ubiquitylation of p53 by antagonizing XIAP. XIAP knockout MEFs express higher p53 protein levels compared to wild-type MEFs. Computational screen for small molecules with high affinity to the ARTS-binding site within XIAP identified a small-molecule ARTS-mimetic, B3. This compound stimulates apoptosis in a wide range of cancer cells but not normal PBMC (Peripheral Blood Mononuclear Cells). Like ARTS, the B3 compound binds to XIAP and promotes its degradation via the UPS. B3 binding to XIAP stabilizes p53 by disrupting its interaction with XIAP. These results reveal a novel mechanism by which ARTS and p53 regulate each other through an amplification loop to promote apoptosis. Finally, these data suggest that targeting the ARTS binding pocket in XIAP can be used to increase p53 levels as a new strategy for developing anti-cancer therapeutics.

The dose disrupts the pathway: application of Paracelsus principle to mechanistic toxicology

Arguably the most famous principle of toxicology is "The dose makes the poison" formulated by Paracelsus in the 16th century. Application of the Paracelsus's principle to mechanistic toxicology may be challenging as one compound may affect many molecular pathways at different doses with different and often nonlinear dose-response relationships. As a result, many mechanistic studies of environmental and occupational compounds use high doses of xenobiotics motivated by the need to see a clear signal indicating disruption of a particular molecular pathway. This approach ignores the possibility that the same xenobiotic may affect different molecular mechanism(s) at much lower doses relevant to human exposures. To amend mechanistic toxicology with a simple and concise guiding principle, I suggest recontextualization of Paracelsus's following its letter and spirit: "The dose disrupts the pathway". Justification of this statement includes observations that many environmental and occupational xenobiotics affect a broad range of molecular cascades, that most molecular pathways are sensitive to chemical exposures, and that different molecular pathways are sensitive to different doses of a chemical compound. I suggest that this statement may become a useful guidance and educational tool in a range of toxicological applications, including experimental design, comparative analysis of mechanistic hypotheses, evaluation of the quality of toxicological studies, and risk assessment.

Prognostic and Therapeutic Implications of Cell Division Cycle 20 Homolog in Breast Cancer

Cell division cycle 20 homolog (CDC20) is a well-known regulator of cell cycle progression. Abnormal expression of CDC20 leads to mitotic defects, which play a significant role in cancer development. In breast cancer (BC), CDC20 has been identified as a biomarker that has been linked to poor patient outcomes. In this study, we investigated the association of CDC20 with BC prognosis and immune cell infiltration by using multiple online databases, including UALCAN, KM plotter, TIMER2.0, HPA, TNM-plot, bc-GenExMiner, LinkedOmics, STRING, and GEPIA. The results demonstrate that BC patients have an elevated CDC20 expression in tumor tissues compared with the adjacent normal tissue. In addition, BC patients with overexpressed CDC20 had a median survival of 63.6 months compared to 169.2 months in patients with low CDC20 expression. Prognostic analysis of the examined data indicated that elevated expression of CDC20 was associated with poor prognosis and a reduction of overall survival in BC patients. These findings were even more prevalent in chemoresistance triple-negative breast cancer (TNBC) patients. Furthermore, the Gene Set Enrichment Analysis tool indicated that CDC20 regulates BC cells' cell cycle and apoptosis. CDC20 also significantly correlates with increased infiltrating B cells, CD4+ T cells, neutrophils, and dendritic cells in BC. In conclusion, the findings of this study suggest that CDC20 may be involved in immunomodulating the tumor microenvironment and provide evidence that CDC20 inhibition may serve as a potential therapeutic approach for the treatment of BC patients. In addition, the data indicates that CDC20 can be a reliable prognostic biomarker for BC.

Comparative Proteomic Analysis of Huh7 Cells Transfected with Sub-Saharan African Hepatitis B Virus (Sub)genotypes Reveals Potential Oncogenic Factors

In sub-Saharan Africa (SSA), the (sub)genotypes A1, D3, and E of the hepatitis B virus (HBV) prevail. Individuals infected with subgenotype A1 have a 4.5-fold increased risk of HCC compared to those infected with other (sub)genotypes. The effect of (sub)genotypes on protein expression and host signalling has not been studied. Mass spectrometry was used to analyse the proteome of Huh7 cells transfected with replication-competent clones. Proteomic analysis revealed significantly differentially expressed proteins between SSA (sub)genotypes. Different (sub)genotypes have the propensity to dysregulate specific host signalling pathways. Subgenotype A1 resulted in dysregulation within the Ras pathway. Ras-associated protein, RhoC, was significantly upregulated in cells transfected with subgenotype A1 compared to those transfected with other (sub)genotypes, on both a proteomic (>1.5-fold) and mRNA level (p < 0.05). Two of the main cellular signalling pathways involving RHOC, MAPK and PI3K/Akt/mTOR, regulate cell growth, motility, and survival. Downstream signalling products of these pathways have been shown to increase MMP2 and MMP9 expression. An extracellular MMP2 and MMP9 ELISA revealed a non-significant increase in MMP2 and MMP9 in the cells transfected with A1 compared to the other (sub)genotypes (p < 0.05). The upregulated Ras-associated proteins have been implicated as oncoproteins in various cancers and could contribute to the increased hepatocarcinogenic potential of A1.

Interleukin-10 induces TNF-driven apoptosis and ROS production in salivary gland cancer cells

Treatment resistance after chemo-/immunotherapy occurs in patients with head and neck squamous cell cancers (HNSCs), including salivary gland cancers (SGCs). Interleukin-10 (IL-10), a cytokine with pro- and anti-cancer effects, has an unclear impact on HNSC/SGC cells. We show that HNSC patients exhibiting high expression of IL-10 and its receptor IL-10Rα experience have prolonged overall survival. Immunoreactive IL-10 was low in ductal cells of human SGC biopsies. Human (A253) and murine WR21-SGC cells expressed IL-10Rβ, but only A253 cells expressed IL-10 and IL-10Rα. The addition of recombinant IL-10 impaired SGC cell proliferation and induced apoptosis in vitro. N-acetylcysteine restored IL-10-induced reactive oxygen species (ROS) production but did not prevent IL-10-mediated viability loss. Mechanistically, recIL-10 delayed cell cycle progression from G0/G1 to the S phase with cyclin D downregulation and upregulation of NF-kB. IL-10 increased tumor necrosis factor-α (TNF-α) in A253 and WR21 and FasL in WR21 cells. Neutralizing antibodies against TNF-α and NF-kB inhibition restored SGC proliferation after IL-10 treatment, emphasizing the critical role of TNF-α and NF-kB in IL-10-mediated anti-tumor effects. These findings underscore the potential of IL-10 to impede SGC cell growth through apoptosis induction, unraveling potential therapeutic targets for intervention in salivary gland carcinomas.

Reactive Oxygen Species Induction by Hepatitis B Virus: Implications for Viral Replication in p53-Positive Human Hepatoma Cells

Hepatitis B virus (HBV) infects approximately 300 million people worldwide, causing chronic infections. The HBV X protein (HBx) is crucial for viral replication and induces reactive oxygen species (ROS), leading to cellular damage. This study explores the relationship between HBx-induced ROS, p53 activation, and HBV replication. Using HepG2 and Hep3B cell lines that express the HBV receptor NTCP, we compared ROS generation and HBV replication relative to p53 status. Results indicated that HBV infection significantly increased ROS levels in p53-positive HepG2-NTCP cells compared to p53-deficient Hep3B-NTCP cells. Knockdown of p53 reduced ROS levels and enhanced HBV replication in HepG2-NTCP cells, whereas p53 overexpression increased ROS and inhibited HBV replication in Hep3B-NTCP cells. The ROS scavenger N-acetyl-L-cysteine (NAC) reversed these effects. The study also found that ROS-induced degradation of the HBx is mediated by the E3 ligase Siah-1, which is activated by p53. Mutations in p53 or inhibition of its transcriptional activity prevented ROS-mediated HBx degradation and HBV inhibition. These findings reveal a p53-dependent negative feedback loop where HBx-induced ROS increases p53 levels, leading to Siah-1-mediated HBx degradation and HBV replication inhibition. This study offers insights into the molecular mechanisms of HBV replication and identifies potential therapeutic targets involving ROS and p53 pathways.

An update on the molecular mechanisms of ZFAS1 as a prognostic, diagnostic, or therapeutic biomarker in cancers

Zinc finger antisense 1 (ZFAS1), a newly discovered long noncoding RNA, is expressed in various tissues and organs and has been introduced an oncogenic gene in human malignancies. In various cancers, ZFAS1 regulates apoptosis, cell proliferation, the cell cycle, migration, translation, rRNA processing, and spliceosomal snRNP assembly; targets signaling cascades; and interacts with transcription factors via binding to key proteins and miRNAs, with conflicting findings on its effect on these processes. ZFAS1 is elevated in different types of cancer, like colorectal, colon, osteosarcoma, and gastric cancer. Considering the ZFAS1 expression pattern, it also has the potential to be a diagnostic or prognostic marker in various cancers. The current review discusses the mode of action of ZFAS1 in various human cancers and its regulation function related to chemoresistance comprehensively, as well as the potential role of ZFAS1 as an effective and noninvasive cancer-specific biomarker in tumor diagnosis, prognosis, and treatment. We expected that the current review could fill the current scientific gaps in the ZFAS1-related cancer causative mechanisms and improve available biomarkers.

Molecular Subtypes and the Role of TP53 in Diffuse Large B-Cell Lymphoma and Richter Syndrome

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoid malignancy and a heterogeneous entity comprised of several biologically distinct subtypes. Recently, novel genetic classifications of DLBCL have been resolved based on common mutational patterns indicative of distinct pathways of transformation. However, the complicated and costly nature of the novel classifiers has precluded their inclusion into routine practice. In view of this, the status of the TP53 gene, which is mutated or deleted in 20-30% of the cases, has emerged as an important prognostic factor for DLBCL patients, setting itself apart from other predictors. TP53 genetic lesions are particularly enriched in a genetic subtype of DLBCL that shares genomic features with Richter Syndrome, highlighting the possibility of a subset of DLBCL arising from the transformation of an occult chronic lymphocytic leukemia-like malignancy, such as monoclonal B-cell lymphocytosis. Patients with TP53-mutated DLBCL, including those with Richter Syndrome, have a particularly poor prognosis and display inferior responses to standard chemoimmunotherapy regimens. The data presented in this manuscript argue for the need for improved and more practical risk-stratification models for patients with DLBCL and show the potential for the use of TP53 mutational status for prognostication and, in prospect, treatment stratification in DLBCL.

Patterns of structural variants within TP53 introns and relocation of the TP53 promoter: a commentary†

Gene disruption from double-strand DNA breaks within introns is a mechanism of inactivating the tumor suppressor TP53. This occurs more frequently in osteosarcoma and biliary adenocarcinoma compared with other cancer types. The patterns of intron breakpoints within TP53 do not correlate with prevalence, intron length, or overall genome-wide levels of rearrangements. Therefore, these breakpoints appear to be selected for reasons other than to disrupt TP53. A recent article published by Saba et al in The Journal of Pathology illustrates a benefit to having breakpoints within intron 1 using high-quality matched genomic and transcriptomic osteosarcoma sequencing data as well as in vitro validation. The authors describe how the rearrangement results in relocation of the TP53 promoter region to regions upstream of genes that encode members of cartilage, growth plate development, osteoclast formation, and other TP53-related pathways. The upregulation of these genes by the TP53 promoter are gain-of-function events that are likely to promote tumor development and growth. Therefore, this article presents a potential new paradigm in which a single mutation would result in both the loss of a tumor suppressor and the gain of an oncogenic program. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Working title: Molecular involvement of p53-MDM2 interactome in gastrointestinal cancers

The interaction between murine double minute 2 (MDM2) and p53, marked by transcriptional induction and feedback inhibition, orchestrates a functional loop dictating cellular fate. The functional loop comprising p53-MDM2 axis is made up of an interactome consisting of approximately 81 proteins, which are spatio-temporally regulated and involved in DNA repair mechanisms. Biochemical and genetic alterations of the interactome result in dysregulation of the p53-mdm2 axis that leads to gastrointestinal (GI) cancers. A large subset of interactome is well known and it consists of proteins that either stabilize p53 or MDM2 and proteins that target the p53-MDM2 complex for ubiquitin-mediated destruction. Upstream signaling events brought about by growth factors and chemical messengers invoke a wide variety of posttranslational modifications in p53-MDM2 axis. Biochemical changes in the transactivation domain of p53 impact the energy landscape, induce conformational switching, alter interaction potential and could change solubility of p53 to redefine its co-localization, translocation and activity. A diverse set of chemical compounds mimic physiological effectors and simulate biochemical modifications of the p53-MDM2 interactome. p53-MDM2 interactome plays a crucial role in DNA damage and repair process. Genetic aberrations in the interactome, have resulted in cancers of GI tract (pancreas, liver, colorectal, gastric, biliary, and esophageal). We present in this article a review of the overall changes in the p53-MDM2 interactors and the effectors that form an epicenter for the development of next-generation molecules for understanding and targeting GI cancers.