Blinded by the Light: The Growing Complexity of p53

Circular RNAs in human diseases

Circular RNAs (circRNAs) are a unique class of RNA molecules formed through back-splicing rather than linear splicing. As an emerging field in molecular biology, circRNAs have garnered significant attention due to their distinct structure and potential functional implications. A comprehensive understanding of circRNAs' functions and potential clinical applications remains elusive despite accumulating evidence of their involvement in disease pathogenesis. Recent research highlights their significant roles in various human diseases, but comprehensive reviews on their functions and applications remain scarce. This review provides an in-depth examination of circRNAs, focusing first on their involvement in non-neoplastic diseases such as respiratory, endocrine, metabolic, musculoskeletal, cardiovascular, and renal disorders. We then explore their roles in tumors, with particular emphasis on exosomal circular RNAs, which are crucial for cancer initiation, progression, and resistance to treatment. By detailing their biogenesis, functions, and impact on disease mechanisms, this review underscores the potential of circRNAs as diagnostic biomarkers and therapeutic targets. The review not only enhances our understanding of circRNAs' roles in specific diseases and tumor types but also highlights their potential as novel diagnostic and therapeutic tools, thereby paving the way for future clinical investigations and potential therapeutic interventions.

The potential role of circular RNAs in regulating p53 in different types of cancers

P53 tumor suppressor is a major regulator of various cellular processes and functions. It has been reported that mutation or inactivation of p53 plays a crucial role in tumorigenesis in different types of cancers. Circular RNAs (circRNAs) are single-stranded non-coding RNAs that have significant post-transcriptional effects on the regulation of gene expression in various ways. These molecules can alter the expression and function of multiple genes and proteins. In the present study, we aimed to review circRNAs that regulate the expression, function, and stability of p53 and the possible interactions between these molecules and p53. Considering the importance of p53 in cancer and the network between p53 and circRNAs, future clinical trials targeting these circRNAs as therapeutic agents deserve worthy of attention.

Comparison of Anticancer, Antioxidant, Enzyme Inhibitory Effects and Phytochemical Contents Between Edible Lettuce (Lactuca sativa) and a New Wild Species (Lactuca anatolica)

In this study, the bioactive components, enzyme inhibitory, antioxidant and anticancer potentials of edible (L. sativa) and a new species (L. anatolica) of Lactuca were evaluated and compared. The quantitative analyzes of the bioactive components of L. sativa (LS) and L. anatolica (LA) were analyzed quantitatively by GC-MS and Orbitrab HPLC-HRMS. Antioxidant, enzyme inhibitory and anticancer properties were analyzed by various assays. In general, LA exhibited more stronger antioxidant properties compared to LS. The extracts showed similar inhibitory effects on these enzymes. It was determined that LS was dominant in terms of linoleic acid (23.71 %), while LA contained a high level of α-linolenic acid (31.70 %). LA and LS inhibited the viability of A549 and MCF-7 cells in a dose-dependent manner. IC50 values for LA, LS and cisplatin were determined as 120.3, 197.5, 4.3 μg/mL in A549 cell line and 286.2, 472.8, 7.2 μg/mL in MCF-7 cell line, respectively. It was revealed that LA and LS treatment at 50 μg/mL concentrations in A549 cells completely suppressed the colony forming capacity, and treatment with IC50 doses inhibited cell migration, and triggered apoptosis by regulating caspase-3, cPARP, p53 and p21. The findings of this study suggested that these species have significant pharmacological potential.

Geometric deep learning of protein-DNA binding specificity

Predicting protein-DNA binding specificity is a challenging yet essential task for understanding gene regulation. Protein-DNA complexes usually exhibit binding to a selected DNA target site, whereas a protein binds, with varying degrees of binding specificity, to a wide range of DNA sequences. This information is not directly accessible in a single structure. Here, to access this information, we present Deep Predictor of Binding Specificity (DeepPBS), a geometric deep-learning model designed to predict binding specificity from protein-DNA structure. DeepPBS can be applied to experimental or predicted structures. Interpretable protein heavy atom importance scores for interface residues can be extracted. When aggregated at the protein residue level, these scores are validated through mutagenesis experiments. Applied to designed proteins targeting specific DNA sequences, DeepPBS was demonstrated to predict experimentally measured binding specificity. DeepPBS offers a foundation for machine-aided studies that advance our understanding of molecular interactions and guide experimental designs and synthetic biology.

Reactive Oxygen Species Mechanisms that Regulate Protein-Protein Interactions in Cancer

Reactive oxygen species (ROS) are produced during cellular metabolism and in response to environmental stress. While low levels of ROS play essential physiological roles, excess ROS can damage cellular components, leading to cell death or transformation. ROS can also regulate protein interactions in cancer cells, thereby affecting processes such as cell growth, migration, and angiogenesis. Dysregulated interactions occur via various mechanisms, including amino acid modifications, conformational changes, and alterations in complex stability. Understanding ROS-mediated changes in protein interactions is crucial for targeted cancer therapies. In this review, we examine the role that ROS mechanisms in regulating pathways through protein-protein interactions.

The ribosomal protein L22 binds the MDM4 pre-mRNA and promotes exon skipping to activate p53 upon nucleolar stress

The tumor suppressor p53 and its antagonists MDM2 and MDM4 integrate stress signaling. For instance, dysbalanced assembly of ribosomes in nucleoli induces p53. Here, we show that the ribosomal protein L22 (RPL22; eL22), under conditions of ribosomal and nucleolar stress, promotes the skipping of MDM4 exon 6. Upon L22 depletion, more full-length MDM4 is maintained, leading to diminished p53 activity and enhanced cellular proliferation. L22 binds to specific RNA elements within intron 6 of MDM4 that correspond to a stem-loop consensus, leading to exon 6 skipping. Targeted deletion of these intronic elements largely abolishes L22-mediated exon skipping and re-enables cell proliferation, despite nucleolar stress. L22 also governs alternative splicing of the L22L1 (RPL22L1) and UBAP2L mRNAs. Thus, L22 serves as a signaling intermediate that integrates different layers of gene expression. Defects in ribosome synthesis lead to specific alternative splicing, ultimately triggering p53-mediated transcription and arresting cell proliferation.

Combination of transcriptomic and proteomic approaches helps unravel the mechanisms of luteolin in inducing liver cancer cell death via targeting AKT1 and SRC

Introduction

Luteolin, a natural compound commonly used in traditional Chinese medicine, shows clinical potential as an anti-liver cancer agent. The mechanisms underlying the anti-liver cancer effect of luteolin are limited versus those reported for other cancers. Accordingly, this study was conducted to bridge the existing knowledge gap.

Methods

Transcriptomic and proteomic analyses of the response of the hepatocellular carcinoma cell line HuH-7 to luteolin were conducted, and a possible pathway was elucidated using confocal laser scanning microscopy (CLSM), flow cytometry, western blotting, qRT-PCR and bio-layer interferometry assay to systematically explore the possible mechanisms underlying the inhibition of the proliferation of liver cancer cells by luteolin.

Results and Discussion

Results showed that luteolin significantly inhibited HuH-7 cell proliferation. Transcriptomic and proteomic analyses collectively revealed that luteolin could promote cell cycle arrest and apoptosis in HuH-7 cells through transcription factors p53, nuclear factor kappa B (NF-κB), FOXO, ATF2, and TCF/LEF via AKT1, as well as the KEAP-NRF and SRC-STAT3 pathways. Furthermore, AKT1 and SRC were identified as the 2 targets of luteolin. Nuclear translocation of transcription factors p53 and NF-κB were affected by luteolin administration. Additionally, AKT1 activity affected normal metabolism in HuH-7 cells and resulted in the accumulation of reactive oxygen species, which activated MOMP and further promoted apoptosis. Our results systematically elucidate the mechanism of luteolin in inhibiting the proliferation of liver cancer cells, mainly through cell cycle arrest and apoptosis via targeting AKT1 and SRC.

Hdm2 disrupts HdmX-mediated nuclear export of p53 by sequestering it in nucleus

Dysfunction of the tumor suppressor p53 occurs in most human cancers, Hdm2 and HdmX play critical roles in p53 inactivation and degradation. Under unstressed conditions, HdmX binds to p53 like Hdm2, but HdmX cannot directly induce p53 degradation. Moreover, HdmX has been reported to stimulate Hdm2-mediated ubiquitination and degradation of p53. Here we reported that HdmX promoted the nuclear export of p53 independent of Hdm2 in living cells using FRET technology. Whereas, Hdm2 impeded HdmX-mediated nuclear export of p53 by sequestering it in nucleus. Interestingly, the C-terminal RING domain mutant Hdm2C464A formed heterooligomers with p53 in nucleus, which was inhibited by HdmX. The heterooligomers were located near PML-NBs. This study indicate that the nuclear Hdm2-HdmX interaction aborts the HdmX-mediated nuclear export of p53.

Molecular mechanisms of sensitivity and resistance to radiotherapy

The molecular mechanisms underlying sensitivity and resistance to radiotherapy is an area of active investigation and discovery as its clinical applications have the potential to improve cancer patients' outcomes. In addition to the traditional pathways of radiation biology, our knowledge now includes molecular pathways of radiation sensitivity and resistance which have provided insights into potential targets for enhancing radiotherapy efficacy. Sensitivity to radiotherapy is influenced by the intricate interplay of various molecular mechanisms involved in DNA damage repair, apoptosis, cellular senescence, and epigenetics. Translationally, there have been several successful applications of this new knowledge into the clinic, such as biomarkers for improved response to chemo-radiation. New therapies to modify radiation response, such as the poly (ADP-ribose) polymerase (PARP) inhibitors, derived from research on DNA repair pathways leading to radiotherapy resistance, are being used clinically. In addition, p53-mediated pathways are critical for DNA damage related apoptosis, cellular senescence, and cell cycle arrest. As the understanding of genetic markers, molecular profiling, molecular imaging, and functional assays improve, these advances once translated clinically, will help propel modern radiation therapy towards more precise and individualized practices.

p53R172H and p53R245W Hotspot Mutations Drive Distinct Transcriptomes in Mouse Mammary Tumors Through a Convergent Transcriptional Mediator

Aggressive breast cancers harbor TP53 missense mutations. Tumor cells with TP53 missense mutations exhibit enhanced growth and survival through transcriptional rewiring. To delineate how TP53 mutations in breast cancer contribute to tumorigenesis and progression in vivo, we created a somatic mouse model driven by mammary epithelial cell-specific expression of Trp53 mutations. Mice developed primary mammary tumors reflecting the human molecular subtypes of luminal A, luminal B, HER2-enriched, and triple-negative breast cancer with metastases. Transcriptomic analyses comparing MaPR172H/- or MaPR245W/- mammary tumors to MaP-/- tumors revealed (1) differences in cancer-associated pathways activated in both p53 mutants and (2) Nr5a2 as a novel transcriptional mediator of distinct pathways in p53 mutants. Meta-analyses of human breast tumors corroborated these results. In vitro assays demonstrate mutant p53 upregulates specific target genes that are enriched for Nr5a2 response elements in their promoters. Co-immunoprecipitation studies revealed p53R172H and p53R245W interact with Nr5a2. These findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer.

SIGNIFICANCE

Our findings implicate NR5A2 as a novel mediator of mutant p53 transcriptional activity in breast cancer. NR5A2 may be an important therapeutic target in hard-to-treat breast cancers such as endocrine-resistant tumors and metastatic triple-negative breast cancers harboring TP53 missense mutations.

MIR193BHG inhibits the proliferation, migration and invasion of trophoblasts by upregulating p53

Aberrant expression of long non-coding RNAs (lncRNAs) serves a crucial role in the biological function of trophoblasts and contributes to preeclampsia (PE). lncRNA MIR193BHG expression is increased in PE placental tissues. In the present study, the effects of MIR193BHG on the function of trophoblasts were assessed to elucidate its underlying molecular mechanisms. The subcellular localization of MIR193BHG in HTR-8/SVneo human first-trimester extravillous trophoblast cells was determined using a fluorescent in situ hybridization assay and by conducting nucleocytoplasmic separation. The effect of MIR193BHG knockdown or overexpression on proliferation, migration, invasion and apoptosis was evaluated in vitro using Cell Counting Kit-8, wound healing, Transwell and flow cytometry assays. RNA-sequencing, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis and protein-protein interaction network construction were subsequently performed to screen the downstream molecules regulated by MIR193BHG. Finally, rescue experiments were conducted to ascertain whether MIR193BHG influenced the biological function of trophoblasts via p53. MIR193BHG was predominantly localized in the nucleus of HTR-8/SVneo cells and overexpression of MIR193BHG significantly inhibited proliferation, migration and invasion, while increasing the rate of apoptosis of HTR-8/SVneo cells. Knockdown of MIR193BHG had the opposite effect. Furthermore, overexpression of MIR193BHG led to increases in both mRNA and protein levels of p53 compared with the control group, and knockdown of p53 rescued the effects induced by overexpression of MIR193BHG on cell proliferation, migration and invasion, while partially counteracting its effects on apoptosis of HTR-8/SVneo cells. In conclusion, the findings of the present study suggested that MIR193BHG served a critical role in progression of PE by regulating the expression of p53, and may be a novel therapeutic target for PE.

JinLiDa granules alleviates cardiac hypertrophy and inflammation in diabetic cardiomyopathy by regulating TP53

BACKGROUND

JinLiDa granules (JLD) is a traditional Chinese medicine (TCM) used to treat type 2 diabetes mellitus with Qi and Yin deficiency. Clinical evidence has shown that JLD can alleviate diabetic cardiomyopathy, but the exact mechanism is not yet clear.

PURPOSE

The purpose of this study was to examine the potential role and mechanism of JLD in the treatment of diabetic cardiomyopathy through network pharmacological analysis and basic experiments.

METHODS

The targets of JLD associated with diabetic cardiomyopathy were examined by network pharmacology. Protein interaction analysis was performed on the targets, and the associated pathways were searched by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Diabetic mice were treated with low or high doses of JLD by gavage, and AC16 and H9C2 cardiomyocytes exposed to high-glucose conditions were treated with JLD. The analysis results were verified by various experimental techniques to examine molecular mechanisms.

RESULTS

Network pharmacological analysis revealed that JLD acted on the tumor suppressor p53 (TP53) during inflammation and fibrosis associated with diabetic cardiomyopathy. The results of basic experiments showed that after JLD treatment, ventricular wall thickening in diabetic mouse hearts was attenuated, cardiac hypertrophy and myocardial inflammation were alleviated, and the expression of cardiac hypertrophy- and inflammation-related factors in cardiomyocytes exposed to a high-glucose environment was decreased. Cardiomyocyte morphology also improved after JLD treatment. TP53 expression and the tumor necrosis factor (TNF) and transforming growth factor beta-1 (TGFβ1) signaling pathways were significantly altered, and inhibiting TP53 expression effectively alleviated the activation of the TNF and TGFβ1 signaling pathways under high glucose conditions. Overexpression of TP53 activated these signaling pathways.

CONCLUSIONS

JLD acted on TP53 to regulate the TNF and TGFβ1 signaling pathways, effectively alleviating cardiomyocyte hypertrophy and inflammation in high glucose and diabetic conditions. Our study provides a solid foundation for the future treatment of diabetic cardiomyopathy with JLD.

Multi-Omics Characterization of E3 Regulatory Patterns in Different Cancer Types

Ubiquitination, a post-translational modification, refers to the covalent attachment of ubiquitin molecules to substrates. This modification plays a critical role in diverse cellular processes such as protein degradation. The specificity of ubiquitination for substrates is regulated by E3 ubiquitin ligases. Dysregulation of ubiquitination has been associated with numerous diseases, including cancers. In our study, we first investigated the protein expression patterns of E3 ligases across 12 cancer types. Our findings indicated that E3 ligases tend to be up-regulated and exhibit reduced tissue specificity in tumors. Moreover, the correlation of protein expression between E3 ligases and substrates demonstrated significant changes in cancers, suggesting that E3-substrate specificity alters in tumors compared to normal tissues. By integrating transcriptome, proteome, and ubiquitylome data, we further characterized the E3-substrate regulatory patterns in lung squamous cell carcinoma. Our analysis revealed that the upregulation of the SKP2 E3 ligase leads to excessive degradation of BRCA2, potentially promoting tumor cell proliferation and metastasis. Furthermore, the upregulation of E3 ubiquitin-protein ligase TRIM33 was identified as a biomarker associated with a favorable prognosis by inhibiting the cell cycle. This work exemplifies how leveraging multi-omics data to analyze E3 ligases across various cancers can unveil prognosis biomarkers and facilitate the identification of potential drug targets for cancer therapy.

p53 at the crossroads of tumor immunity

The p53 tumor suppressor protein has a plethora of cell-intrinsic functions and consequences that impact diverse cell types and tissues. Recent studies are beginning to unravel how wild-type and mutant p53 work in distinct ways to modulate tumor immunity. This sets up a disequilibrium between tumor immunosurveillance and escape therefrom. The ability to exploit this emerging knowledge for translational approaches may shape immunotherapy and targeted therapeutics in the future, especially in combinatorial settings.

Nerve-tumor crosstalk in tumor microenvironment: From tumor initiation and progression to clinical implications

The autonomic nerve system (ANS) innervates organs and tissues throughout the body and maintains functional balance among various systems. Further investigations have shown that excessive activation of ANS not only causes disruption of homeostasis, but also may promote tumor formation. In addition, the dynamic interaction between nerve and tumor cells in the tumor microenvironment also regulate tumor progression. On the one hand, nerves are passively invaded by tumor cells, that is, perineural invasion (PNI). On the other hand, compared with normal tissues, tumor tissues are subject to more abundant innervation, and nerves can influence tumor progression through regulating tumor proliferation, metastasis and drug resistance. A large number of studies have shown that nerve-tumor crosstalk, including PNI and innervation, is closely related to the prognosis of patients, and contributes to the formation of cancer pain, which significantly deteriorates the quality of life for patients. These findings suggest that nerve-tumor crosstalk represents a potential target for anti-tumor therapies and the management of cancer pain in the future. In this review, we systematically describe the mechanism by which nerve-tumor crosstalk regulates tumorigenesis and progression.

The next decade of SET: from an oncoprotein to beyond

This year marks the fourth decade of research into the protein SET, which was discovered in 1992. SET was initially identified as an oncoprotein but later shown to be a multifaceted protein involved in regulating numerous biological processes under both physiological and pathophysiological conditions. SET dysfunction is closely associated with diseases, such as cancer and Alzheimer's disease. With the increasing understanding of how SET works and how it is regulated in cells, targeting aberrant SET has emerged as a potential strategy for disease intervention. In this review, we present a comprehensive overview of the advancements in SET studies, encompassing its biological functions, regulatory networks, clinical implications, and pharmacological inhibitors. Furthermore, we provide insights into the future prospects of SET research, with a particular emphasis on its promising potential in the realm of immune modulation.

Twenty years of Gendicine® rAd-p53 cancer gene therapy: The first-in-class human cancer gene therapy in the era of personalized oncology

Genetic mutations in TP53 contribute to human malignancies through various means. To date, there have been a variety of therapeutic strategies targeting p53, including gene therapy to restore normal p53 function, mutant p53 rescue, inhibiting the MDM2-p53 interaction, p53-based vaccines, and a number of other approaches. This review focuses on the functions of TP53 and discusses the aberrant roles of mutant p53 in various types of cancer. Recombinant human p53 adenovirus, trademarked as Gendicine, which is the first anti-tumor gene therapy drug, has made tremendous progress in cancer gene therapy. We herein discuss the biological mechanisms by which Gendicine exerts its effects and describe the clinical responses reported in clinical trials. Notably, the clinical studies suggest that the combination of Gendicine with chemotherapy and/or radiotherapy may produce more pronounced efficacy in slowing tumor growth and progression than gene therapy/chemotherapy alone. Finally, we summarize the methods of administration of recombinant human p53 adenovirus for different cancer types to provide a reference for future clinical trials.

P53 upregulation by USP7-engaging molecular glues

Molecular glues are typically small chemical molecules that act at the interface between a target protein and degradation machinery to trigger ternary complex formation. Identifying molecular glues is challenging. There is a scarcity of target-specific upregulating molecular glues, which are highly anticipated for numerous targets, including P53. P53 is degraded in proteasomes through polyubiquitination by specific E3 ligases, whereas deubiquitinases (DUBs) remove polyubiquitination conjugates to counteract these E3 ligases. Thus, small-molecular glues that enhance P53 anchoring to DUBs may stabilize P53 through deubiquitination. Here, using small-molecule microarray-based technology and unbiased screening, we identified three potential molecular glues that may tether P53 to the DUB, USP7, and elevate the P53 level. Among the molecular glues, bromocriptine (BC) is an FDA-approved drug with the most robust effects. BC was further verified to increase P53 stability via the predicted molecular glue mechanism engaging USP7. Consistent with P53 upregulation in cancer cells, BC was shown to inhibit the proliferation of cancer cells in vitro and suppress tumor growth in a xenograft model. In summary, we established a potential screening platform and identified potential molecular glues upregulating P53. Similar strategies could be applied to the identification of other types of molecular glues that may benefit drug discovery and chemical biology studies.

p53 Genetics and Biology in Lung Carcinomas: Insights, Implications and Clinical Applications

The TP53 gene is renowned as a tumor suppressor, playing a pivotal role in overseeing the cell cycle, apoptosis, and maintaining genomic stability. Dysregulation of p53 often contributes to the initiation and progression of various cancers, including lung cancer (LC) subtypes. The review explores the intricate relationship between p53 and its role in the development and progression of LC. p53, a crucial tumor suppressor protein, exists in various isoforms, and understanding their distinct functions in LC is essential for advancing our knowledge of this deadly disease. This review aims to provide a comprehensive literature overview of p53, its relevance to LC, and potential clinical applications.

MLIP and Its Potential Influence on Key Oncogenic Pathways

Muscle-enriched A-type lamin-interacting protein (MLIP) is an emerging protein involved in cellular homeostasis and stress adaptation. Eukaryotic cells regulate various cellular processes, including metabolism, DNA repair, and cell cycle progression, to maintain cellular homeostasis. Disruptions in this homeostasis can lead to diseases such as cancer, characterized by uncontrolled cell growth and division. This review aims to explore for the first time the unique role MLIP may play in cancer development and progression, given its interactions with the PI3K/Akt/mTOR pathway, p53, MAPK9, and FOXO transcription factors, all critical regulators of cellular homeostasis and tumor suppression. We discuss the current understanding of MLIP's involvement in pro-survival pathways and its potential implications in cancer cells' metabolic remodeling and dysregulated homeostasis. Additionally, we examine the potential of MLIP as a novel therapeutic target for cancer treatment. This review aims to shed light on MLIP's potential impact on cancer biology and contribute to developing innovative therapeutic strategies.

Suppression of P53 Pathway is an Important Factor Inducing Acute Graft-versus-Host Disease Through T Cell Activation Based on Bioinformatics Analysis

Purpose

Acute graft-versus-host disease (aGVHD) poses a significant impediment to achieving a more favourable therapeutic outcome in allogeneic hematopoietic stem cell transplantation (allo-HSCT). The tumour suppressor p53 plays a pivotal role in preventing aGVHD development. However, whether P53 pathway which contains p53 family members and other related genes participates in aGVHD development remains an unsolved question.

Patients and Methods

Transcriptomic data was obtained from Gene Expression Omnibus (GEO) database. Gene set enrichment analysis was applied to determine the enrichment degree of signaling pathways. CIBERSORT and ssGSVA were used to evaluate immune cell compositions. Univariate and multivariate logistic regression analysis were performed to examine the independent diagnostic variables. qRT-PCR was utilized to validate the genes expression levels in our cohort.

Results

A total number of 102 patients (42 aGVHD patients vs 60 non-aGVHD patients) were obtained after integrating two datasets in GEO database (GSE73809 and GSE4624). P53 pathway was remarkably suppressed in T cells from aGVHD patients and negatively associated with activated T cells as well as T cells activation related signaling pathways, including T-cell receptor (TCR), mTORC1, MYC and E2F target pathways. A risk model for aGVHD built by four genes (DDIT3, FBXW7, TPRKB and TOB1) in P53 pathway, exhibiting high differentiate and predictive value. DDIT3 and FBXW7 mRNA expression levels significantly decreased in peripheral blood mononuclear cells (PBMCs) from aGVHD patients compared with non-aGVHD group in our patient cohort, consisting with bioinformatics analysis.

Conclusion

P53 pathway plays a potential role in impeding T cell activation through suppressing its related signaling pathways, thereby preventing aGVHD development. P53 pathway may emerge as a promising therapeutic target in aGVHD treatment.

ESR1 and p53 interactome alteration defines mechanisms of tamoxifen response in luminal breast cancer

The canonical mechanism behind tamoxifen's therapeutic effect on estrogen receptor α/ESR1+ breast cancers is inhibition of ESR1-dependent estrogen signaling. Although ESR1+ tumors expressing wild-type p53 were reported to be more responsive to tamoxifen (Tam) therapy, p53 has not been factored into choice of this therapy and the mechanism underlying the role of p53 in Tam response remains unclear. In a window-of-opportunity trial on patients with newly diagnosed stage I-III ESR1+/HER2/wild-type p53 breast cancer who were randomized to arms with or without Tam prior to surgery, we reveal that the ESR1-p53 interaction in tumors was inhibited by Tam. This resulted in functional reactivation of p53 leading to transcriptional reprogramming that favors tumor-suppressive signaling, as well as downregulation of oncogenic pathways. These findings illustrating the convergence of ESR1 and p53 signaling during Tam therapy enrich mechanistic understanding of the impact of p53 on the response to Tam therapy.

Understanding the complexity of p53 in a new era of tumor suppression

p53 was discovered 45 years ago as an SV40 large T antigen binding protein, coded by the most frequently mutated TP53 gene in human cancers. As a transcription factor, p53 is tightly regulated by a rich network of post-translational modifications to execute its diverse functions in tumor suppression. Although early studies established p53-mediated cell-cycle arrest, apoptosis, and senescence as the classic barriers in cancer development, a growing number of new functions of p53 have been discovered and the scope of p53-mediated anti-tumor activity is largely expanded. Here, we review the complexity of different layers of p53 regulation, and the recent advance of the p53 pathway in metabolism, ferroptosis, immunity, and others that contribute to tumor suppression. We also discuss the challenge regarding how to activate p53 function specifically effective in inhibiting tumor growth without harming normal homeostasis for cancer therapy.

Modeling of Intracellular Taurine Levels Associated with Ovarian Cancer Reveals Activation of p53, ERK, mTOR and DNA-Damage-Sensing-Dependent Cell Protection

Taurine, a non-proteogenic amino acid and commonly used nutritional supplement, can protect various tissues from degeneration associated with the action of the DNA-damaging chemotherapeutic agent cisplatin. Whether and how taurine protects human ovarian cancer (OC) cells from DNA damage caused by cisplatin is not well understood. We found that OC ascites-derived cells contained significantly more intracellular taurine than cell culture-modeled OC. In culture, elevation of intracellular taurine concentration to OC ascites-cell-associated levels suppressed proliferation of various OC cell lines and patient-derived organoids, reduced glycolysis, and induced cell protection from cisplatin. Taurine cell protection was associated with decreased DNA damage in response to cisplatin. A combination of RNA sequencing, reverse-phase protein arrays, live-cell microscopy, flow cytometry, and biochemical validation experiments provided evidence for taurine-mediated induction of mutant or wild-type p53 binding to DNA, activation of p53 effectors involved in negative regulation of the cell cycle (p21), and glycolysis (TIGAR). Paradoxically, taurine's suppression of cell proliferation was associated with activation of pro-mitogenic signal transduction including ERK, mTOR, and increased mRNA expression of major DNA damage-sensing molecules such as DNAPK, ATM and ATR. While inhibition of ERK or p53 did not interfere with taurine's ability to protect cells from cisplatin, suppression of mTOR with Torin2, a clinically relevant inhibitor that also targets DNAPK and ATM/ATR, broke taurine's cell protection. Our studies implicate that elevation of intracellular taurine could suppress cell growth and metabolism, and activate cell protective mechanisms involving mTOR and DNA damage-sensing signal transducti.

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.

Discovery of potent small molecule ubiquitin-specific protease 10 inhibitors with anti-hepatocellular carcinoma activity through regulating YAP expression

High expression of ubiquitin-specific protease 10 (USP10) promote the proliferation of hepatocellular carcinoma (HCC), thus the development of USP10 inhibitors holds promise as a novel therapeutic approach for HCC treatment. However, the development of selective USP10 inhibitor is still limited. In this study, we developed a novel USP10 inhibitor for investigating the feasibility of targeting USP10 for the treatment of HCC. Due to high USP10 inhibition potency and prominent selectivity, compound D1 bearing quinolin-4(1H)-one scaffold was identified as a lead compound. Subsequent research revealed that D1 significantly inhibits cell proliferation and clone formation in HCC cells. Mechanistic insights indicated that D1 targets the ubiquitin pathway, facilitating the degradation of YAP (Yes-associated protein), thereby triggering the downregulation of p53 and its downstream protein p21. Ultimately, this cascade leads to S-phase arrest in HCC cells, followed by cell apoptosis. Collectively, our findings highlight D1 as a promising starting point for USP10-positive HCC treatment, underscoring its potential as a vital tool for unraveling the functional intricacies of USP10.

Systematic Characterization of p53-Regulated Long Noncoding RNAs across Human Cancers Reveals Remarkable Heterogeneity among Different Tumor Types

The p53 tumor suppressor protein, a sequence-specific DNA binding transcription factor, regulates the expression of a large number of genes, in response to various forms of cellular stress. Although the protein coding target genes of p53 have been well studied, less is known about its role in regulating long noncoding genes and their functional relevance to cancer. Here we report the genome-wide identification of a large set (>1,000) of long noncoding RNAs (lncRNA), which are putative p53 targets in a colon cancer cell line and in human patient datasets from five different common types of cancer. These lncRNAs have not been annotated by other studies of normal unstressed systems. In the colon cancer cell line, a high proportion of these lncRNAs are uniquely induced by different chemotherapeutic agents that activate p53, whereas others are induced by more than one agent tested. Further, subsets of these lncRNAs independently predict overall and disease-free survival of patients across the five different common cancer types. Interestingly, both genetic alterations and patient survival associated with different lncRNAs are unique to each cancer tested, indicating extraordinary tissue-specific variability in the p53 noncoding response. The newly identified noncoding p53 target genes have allowed us to construct a classifier for tumor diagnosis and prognosis.

IMPLICATIONS

Our results not only identify myriad p53-regulated long noncoding (lncRNA), they also reveal marked drug-induced, as well as tissue- and tumor-specific heterogeneity in these putative p53 targets and our findings have enabled the construction of robust classifiers for diagnosis and prognosis.

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.

miR-192 family in breast cancer: Regulatory mechanisms and diagnostic value

There is a growing interest in the role of the miRNA family in human cancer. The miRNA-192 family is a group of conserved small RNAs, including miR-192, miR-194, and miR-215. Recent studies have shown that the incidence and mortality of breast cancer have been increasing epidemiologically year by year, and it is urgent to clarify the pathogenesis of breast cancer and seek new diagnostic and therapeutic methods. There is increasing evidence that miR-192 family members may be involved in the occurrence and development of breast cancer. This review describes the regulatory mechanism of the miRNA-192 family affecting the malignant behavior of breast cancer cells and evaluates the value of the miRNA-192 family as a diagnostic and prognostic biomarker for breast cancer. It is expected that summarizing and discussing the relationship between miRNA-192 family members and breast cancer, it will provide a new direction for the clinical diagnosis and treatment of breast cancer and basic medical research.

Eliminating elevated p53 signaling fails to rescue skeletal muscle defects or extend survival in lamin A/C-deficient mice

Lamins A and C, encoded by the LMNA gene, are nuclear intermediate filaments that provide structural support to the nucleus and contribute to chromatin organization and transcriptional regulation. LMNA mutations cause muscular dystrophies, dilated cardiomyopathy, and other diseases. The mechanisms by which many LMNA mutations result in muscle-specific diseases have remained elusive, presenting a major hurdle in the development of effective treatments. Previous studies using striated muscle laminopathy mouse models found that cytoskeletal forces acting on mechanically fragile Lmna-mutant nuclei led to transient nuclear envelope rupture, extensive DNA damage, and activation of DNA damage response (DDR) pathways in skeletal muscle cells in vitro and in vivo. Furthermore, hearts of Lmna mutant mice have elevated activation of the tumor suppressor protein p53, a central regulator of DDR signaling. We hypothesized that elevated p53 activation could present a pathogenic mechanism in striated muscle laminopathies, and that eliminating p53 activation could improve muscle function and survival in laminopathy mouse models. Supporting a pathogenic function of p53 activation in muscle, stabilization of p53 was sufficient to reduce contractility and viability in wild-type muscle cells in vitro. Using three laminopathy models, we found that increased p53 activity in Lmna-mutant muscle cells primarily resulted from mechanically induced damage to the myonuclei, and not from altered transcriptional regulation due to loss of lamin A/C expression. However, global deletion of p53 in a severe muscle laminopathy model did not reduce the disease phenotype or increase survival, indicating that additional drivers of disease must contribute to the disease pathogenesis.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

MicroRNAs and angiosarcoma: are there promising reports?

In recent years, microRNAs (miRNAs) have garnered increasing attention for their potential implications in cancer pathogenesis, functioning either as oncogenes or tumor suppressors. Notably, angiosarcoma, along with various other cardiovascular tumors such as lipomas, rhabdomyomas, hemangiomas, and myxomas, has shown variations in the expression of specific miRNA subtypes. A substantial body of evidence underscores the pivotal involvement of miRNAs in the genesis of angiosarcoma and certain cardiovascular tumors. This review aims to delve into the current literature on miRNAs and their prospective applications in cardiovascular malignancies, with a specific focus on angiosarcoma. It comprehensively covers diagnostic methods, prognostic evaluations, and potential treatments while providing a recapitulation of angiosarcoma's risk factors and molecular pathogenesis, with an emphasis on the role of miRNAs. These insights can serve as the groundwork for designing randomized control trials, ultimately facilitating the translation of these findings into clinical applications. Moving forward, it is imperative for studies to thoroughly scrutinize the advantages and disadvantages of miRNAs compared to current diagnostic and prognostic approaches in angiosarcoma and other cardiovascular tumors. Closing these knowledge gaps will be crucial for harnessing the full potential of miRNAs in the realm of angiosarcoma and cardiovascular tumor research.

Detection of uridine diphosphate glucuronosyltransferase 1A1 for pancreatic cancer imaging and treatment via a "turn-on" fluorescent probe

Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) is expressed ubiquitously in cancer cells and can metabolize exogenous substances. Studies show higher UGT1A1 levels in pancreatic cancer cells than normal cells. Therefore, we need a method to monitor the activity level of UGT1A1 in pancreatic cancer cells and in vivo. Here, we report a fluorescent probe, BCy-panc, for UGT1A1 imaging in cells and in vivo. Compared with other molecular probes, this probe is readily prepared, with high selectivity and sensitivity for the detection of UGT1A1. Our results show that BCy-panc rapidly detects UGT1A1 in pancreatic cancer. In addition, there is an urgent need for evidence to clarify the relationship between UGT1A1 and pancreatic cancer development. The present investigation found that the increase of UGT1A1 by chrysin was effective in inducing apoptosis in pancreatic cancer cells. These results indicate that the synergistic effect of chrysin and cisplatin at the cellular level is superior to that of cisplatin alone. The UGT1A1 level may be a biomarker for early diagnosis of cancer. Meanwhile, UGT1A1 plays a crucial role in pancreatic cancer, and the combination of chrysin and cisplatin may provide effective ideas for pancreatic cancer treatment.

Prognostic Impact of TP53 Mutations in Metastatic Nonsquamous Non-small-cell Lung Cancer

BACKGROUND

The prognostic impact of TP53 mutations in advanced or metastatic nonsquamous non-small-cell lung cancer (nsNSCLC) patients treated with chemotherapy and/or immune checkpoint inhibitors (ICI) remains unclear.

MATERIALS AND METHODS

We retrospectively collected data from patients with nsNSCLC treated in the first line from January 2018 to May 2021. The patient was separated into 2 groups according to their TP53 mutation status (wt vs. mut). Survival was estimated through the Kaplan-Meier method and compared by log-rank test.

RESULTS

Of 220 patients included, 126 were in the mutTP53 group, and 94 were in the wtTP53wt group. Median OS (mOS) was not significantly different between the mutTP53 and wtTP53 groups [17.5 months (95% confidence interval (CI), 11.3-21.5) vs. 9.5 months (95% CI, 7.4-14.2), (P = .051)]. In subgroup analyses, the mutTP53 group treated with ICI had a significantly improved mOS compared to the wtTP53 group [(24.7 months (95% CI, 20.8-not reach) vs. 12.0 months (95% CI, 4.7-not reach), (P = .017)] and mPFS [(9.6 months (95% CI, 5.8-not reach) vs. 3.2 months (95% CI, 1.3-13.8) (P = .048)]. There was no difference in terms of mOS and mPFS between the mutTP53 and the wtTP53 group treated by chemotherapy alone or combined with ICI.

CONCLUSION

TP53 mutation had no survival impact in the overall population, but is associated with better outcomes with ICI alone. These results suggest that patients with TP53 mutations could be treated with ICI alone, and wild-type patients could benefit from the addition of chemotherapy.

HOPS/TMUB1 Enhances Apoptosis in TP53 Mutation-Independent Setting in Human Cancers

TP53 mutations are prevalent in various cancers, yet the complexity of apoptotic pathway deregulation suggests the involvement of additional factors. HOPS/TMUB1 is known to extend the half-life of p53 under normal and stress conditions, implying a regulatory function. This study investigates, for the first time, the potential modulatory role of the ubiquitin-like-protein HOPS/TMUB1 in p53-mutants. A comprehensive analysis of apoptosis in the most frequent p53-mutants, R175, R248, and R273, in SKBR3, MIA PaCa2, and H1975 cells indicates that the overexpression of HOPS induces apoptosis at least equivalent to that caused by DNA damage. Immunoprecipitation assays confirm HOPS binding to p53-mutant forms. The interaction of HOPS/TMUB1 with p53-mutants strengthens its effect on the apoptotic cascade, showing a context-dependent gain or loss of function. Gene expression analysis of the MYC and TP63 genes shows that H1975 exhibit a gain-of-function profile, while SKBR3 promote apoptosis in a TP63-dependent manner. The TCGA data further corroborate HOPS/TMUB1's positive correlation with apoptotic genes BAX, BBC3, and NOXA1, underscoring its relevance in patient samples. Notably, singular TP53 mutations inadequately explain pathway dysregulation, emphasizing the need to explore additional contributing factors. These findings illuminate the intricate interplay among TP53 mutations, HOPS/TMUB1, and apoptotic pathways, providing valuable insights for targeted cancer interventions.

Loss of the vitamin D receptor triggers senescence in chronic myeloid leukemia via DDIT4-mediated DNA damage

Chronic myeloid leukemia (CML) is a hematopoietic malignancy driven by the fusion gene BCR::ABL1. Drug resistance to tyrosine kinase inhibitors (TKIs), due to BCR::ABL1 mutations and residual leukemia stem cells (LSCs), remains a major challenge in CML treatment. Here, we revealed the requirement of the vitamin D receptor (VDR) in the progression of CML. VDR was upregulated by BCR::ABL1 and highly expressed in CML cells. Interestingly, VDR knockdown inhibited the proliferation of CML cells driven by both BCR::ABL1 and TKI-resistant BCR::ABL1 mutations. Mechanistically, VDR transcriptionally regulated DDIT4 expression; reduced DDIT4 levels upon VDR knockdown triggered DNA damage and senescence via p53 signaling activation in CML cells. Furthermore, VDR deficiency not only suppressed tumor burden and progression in primary CML mice but also reduced the self-renewal capacity of CML-LSCs. Together, our study demonstrated that targeting VDR is a promising strategy to overcome TKI resistance and eradicate LSCs in CML.

p53 Acetylation Exerts Critical Roles in Pressure Overload-Induced Coronary Microvascular Dysfunction and Heart Failure in Mice

BACKGROUND

Coronary microvascular dysfunction (CMD) has been shown to contribute to cardiac hypertrophy and heart failure (HF) with preserved ejection fraction. At this point, there are no proven treatments for CMD.

METHODS

We have shown that histone acetylation may play a critical role in the regulation of CMD. By using a mouse model that replaces lysine with arginine at residues K98, K117, K161, and K162R of p53 (p534KR), preventing acetylation at these sites, we test the hypothesis that acetylation-deficient p534KR could improve CMD and prevent the progression of hypertensive cardiac hypertrophy and HF. Wild-type and p534KR mice were subjected to pressure overload by transverse aortic constriction to induce cardiac hypertrophy and HF.

RESULTS

Echocardiography measurements revealed improved cardiac function together with a reduction of apoptosis and fibrosis in p534KR mice. Importantly, myocardial capillary density and coronary flow reserve were significantly improved in p534KR mice. Moreover, p534KR upregulated the expression of cardiac glycolytic enzymes and Gluts (glucose transporters), as well as the level of fructose-2,6-biphosphate; increased PFK-1 (phosphofructokinase 1) activity; and attenuated cardiac hypertrophy. These changes were accompanied by increased expression of HIF-1α (hypoxia-inducible factor-1α) and proangiogenic growth factors. Additionally, the levels of SERCA-2 were significantly upregulated in sham p534KR mice, as well as in p534KR mice after transverse aortic constriction. In vitro, p534KR significantly improved endothelial cell glycolytic function and mitochondrial respiration and enhanced endothelial cell proliferation and angiogenesis. Similarly, acetylation-deficient p534KR significantly improved coronary flow reserve and rescued cardiac dysfunction in SIRT3 (sirtuin 3) knockout mice.

CONCLUSIONS

Our data reveal the importance of p53 acetylation in coronary microvascular function, cardiac function, and remodeling and may provide a promising approach to improve hypertension-induced CMD and to prevent the transition of cardiac hypertrophy to HF.

p53 rapidly restructures 3D chromatin organization to trigger a transcriptional response

Activation of the p53 tumor suppressor triggers a transcriptional program to control cellular response to stress. However, the molecular mechanisms by which p53 controls gene transcription are not completely understood. Here, we uncover the critical role of spatio-temporal genome architecture in this process. We demonstrate that p53 drives direct and indirect changes in genome compartments, topologically associating domains, and DNA loops prior to one hour of its activation, which escort the p53 transcriptional program. Focusing on p53-bound enhancers, we report 340 genes directly regulated by p53 over a median distance of 116 kb, with 74% of these genes not previously identified. Finally, we showcase that p53 controls transcription of distal genes through newly formed and pre-existing enhancer-promoter loops in a cohesin dependent manner. Collectively, our findings demonstrate a previously unappreciated architectural role of p53 as regulator at distinct topological layers and provide a reliable set of new p53 direct target genes that may help designs of cancer therapies.

Review: Protein O-GlcNAcylation regulates DNA damage response: A novel target for cancer therapy

The DNA damage response (DDR) safeguards the stable genetic information inheritance by orchestrating a complex protein network in response to DNA damage. However, this mechanism can often hamper the effectiveness of radiotherapy and DNA-damaging chemotherapy in destroying tumor cells, causing cancer resistance. Inhibiting DDR can significantly improve tumor cell sensitivity to radiotherapy and DNA-damaging chemotherapy. Thus, DDR can be a potential target for cancer treatment. Post-translational modifications (PTMs) of DDR-associated proteins profoundly affect their activity and function by covalently attaching new functional groups. O-GlcNAcylation (O-linked-N-acetylglucosaminylation) is an emerging PTM associated with adding and removing O-linked N-acetylglucosamine to serine and threonine residues of proteins. It acts as a dual sensor for nutrients and stress in the cell and is sensitive to DNA damage. However, the explanation behind the specific role of O-GlcNAcylation in the DDR remains remains to be elucidated. To illustrate the complex relationship between O-GlcNAcylation and DDR, this review systematically describes the role of O-GlcNAcylation in DNA repair, cell cycle, and chromatin. We also discuss the defects of current strategies for targeting O-GlcNAcylation-regulated DDR in cancer therapy and suggest potential directions to address them.

p53: A tale of complexity and context

The story of p53 is illuminating. Despite widespread attention, the tumor-suppressive functions of wild-type p53 or the oncogenic activities of its cancer-associated mutants are still not fully understood, and our discoveries have not yet led to major therapeutic breakthroughs. There is still much to learn about this fascinating protein.

Xrp1 governs the stress response program to spliceosome dysfunction

Co-transcriptional processing of nascent pre-mRNAs by the spliceosome is vital to regulating gene expression and maintaining genome integrity. Here, we show that the deficiency of functional U5 small nuclear ribonucleoprotein particles (snRNPs) in Drosophila imaginal cells causes extensive transcriptome remodeling and accumulation of highly mutagenic R-loops, triggering a robust stress response and cell cycle arrest. Despite compromised proliferative capacity, the U5 snRNP-deficient cells increased protein translation and cell size, causing intra-organ growth disbalance before being gradually eliminated via apoptosis. We identify the Xrp1-Irbp18 heterodimer as the primary driver of transcriptional and cellular stress program downstream of U5 snRNP malfunction. Knockdown of Xrp1 or Irbp18 in U5 snRNP-deficient cells attenuated JNK and p53 activity, restored normal cell cycle progression and growth, and inhibited cell death. Reducing Xrp1-Irbp18, however, did not rescue the splicing defects, highlighting the requirement of accurate splicing for cellular and tissue homeostasis. Our work provides novel insights into the crosstalk between splicing and the DNA damage response and defines the Xrp1-Irbp18 heterodimer as a critical sensor of spliceosome malfunction and mediator of the stress-induced cellular senescence program.

Senescence: A DNA damage response and its role in aging and Neurodegenerative Diseases

Senescence is a complicated, multi-factorial, irreversible cell cycle halt that has a tumor-suppressing effect in addition to being a significant factor in aging and neurological diseases. Damaged DNA, neuroinflammation, oxidative stress and disrupted proteostasis are a few of the factors that cause senescence. Senescence is triggered by DNA damage which initiates DNA damage response. The DNA damage response, which includes the formation of DNA damage foci containing activated H2AX, which is a key factor in cellular senescence, is provoked by a double strand DNA break. Oxidative stress impairs cognition, inhibits neurogenesis, and has an accelerated aging effect. Senescent cells generate pro-inflammatory mediators known as senescence-associated secretory phenotype (SASP). These pro-inflammatory cytokines and chemokines have an impact on neuroinflammation, neuronal death, and cell proliferation. While it is tempting to think of neurodegenerative diseases as manifestations of accelerated aging and senescence, this review will present information on brain ageing and neurodegeneration as a result of senescence and DNA damage response.

Kielin/chordin-like protein deficiency aggravates pressure overload-induced cardiac dysfunction and remodeling via P53/P21/CCNB1 signaling in mice

Targeting cardiac remodeling is regarded as a key therapeutic strategy for heart failure. Kielin/chordin-like protein (KCP) is a secretory protein with 18 cysteine-rich domains and associated with kidney and liver fibrosis. However, the relationship between KCP and cardiac remodeling remains unclear. Here, we aimed to investigate the role of KCP in cardiac remodeling induced by pressure overload and explore its potential mechanisms. Left ventricular (LV) KCP expression was measured with real-time quantitative PCR, western blotting, and immunofluorescence staining in pressure overload-induced cardiac remodeling in mice. Cardiac function and remodeling were evaluated in wide-type (WT) mice and KCP knockout (KO) mice by echocardiography, which were further confirmed by histological analysis with hematoxylin and eosin and Masson staining. RNA sequence was performed with LV tissue from WT and KO mice to identify differentially expressed genes and related signaling pathways. Primary cardiac fibroblasts (CFs) were used to validate the regulatory role and potential mechanisms of KCP during fibrosis. KCP was down-regulated in the progression of cardiac remodeling induced by pressure overload, and was mainly expressed in fibroblasts. KCP deficiency significantly aggravated pressure overload-induced cardiac dysfunction and remodeling. RNA sequence revealed that the role of KCP deficiency in cardiac remodeling was associated with cell division, cell cycle, and P53 signaling pathway, while cyclin B1 (CCNB1) was the most significantly up-regulated gene. Further investigation in vivo and in vitro suggested that KCP deficiency promoted the proliferation of CFs via P53/P21/CCNB1 pathway. Taken together, these results suggested that KCP deficiency aggravates cardiac dysfunction and remodeling induced by pressure overload via P53/P21/CCNB1 signaling in mice.

GRWD1 Over-Expression Promotes Gastric Cancer Progression by Activating Notch Signaling Pathway via Up-Regulation of ADAM17

BACKGROUND

Glutamate-rich WD repeat containing 1 (GRWD1) is over-expressed in a variety of malignant tumors and is considered to be a potential oncogene. However, its mechanism of action in gastric cancer (GC) is still unclear.

METHODS

Data analysis, Immunohistochemistry, and Western Blot (WB) were performed to verify the expression of GRWD1 in GC and para-cancerous tissues. The association between GRWD1 expression and tumor size, tissue differentiation, lymph node metastasis, TNM stage, and prognosis was analyzed according to the high and low expression levels of GRWD1. The relationship between GRWD1 and Notch pathway was verified by data analysis and WB. The effects of GRWD1 on the proliferation, migration, and invasion of GC cells were verified by cell proliferation, migration, and invasion assays. We confirmed that the high expression of GRWD1 promoted the proliferation of GC cells in vivo through the tumor formation assay in nude mice.

RESULTS

The expression of GRWD1 was higher in GC tissues than in para-cancerous tissues, and its expression was positively correlated with tumor size, lymph node metastasis, and TNM stage, but negatively correlated with differentiation grade and prognosis. GRWD1 over-expression increased ADAM metallopeptidase domain 17 (ADAM17) expression and promoted Notch1 intracellular domain (NICD) release to promote GC cell proliferation, migration, and invasion in vitro. Results from animal studies have shown that high GRWD1 expression could promote GC cell proliferation in vivo by activating the Notch signaling pathway.

CONCLUSION

GRWD1 promotes GC progression through ADAM17-dependent Notch signaling, and GRWD1 may be a novel tumor marker and therapeutic target.

Translating p53-based therapies for cancer into the clinic

Inactivation of the most important tumour suppressor gene TP53 occurs in most, if not all, human cancers. Loss of functional wild-type p53 is achieved via two main mechanisms: mutation of the gene leading to an absence of tumour suppressor activity and, in some cases, gain-of-oncogenic function; or inhibition of the wild-type p53 protein mediated by overexpression of its negative regulators MDM2 and MDMX. Because of its high potency as a tumour suppressor and the dependence of at least some established tumours on its inactivation, p53 appears to be a highly attractive target for the development of new anticancer drugs. However, p53 is a transcription factor and therefore has long been considered undruggable. Nevertheless, several innovative strategies have been pursued for targeting dysfunctional p53 for cancer treatment. In mutant p53-expressing tumours, the predominant strategy is to restore tumour suppressor function with compounds acting either in a generic manner or otherwise selective for one or a few specific p53 mutations. In addition, approaches to deplete mutant p53 or to target vulnerabilities created by mutant p53 expression are currently under development. In wild-type p53 tumours, the major approach is to protect p53 from the actions of MDM2 and MDMX by targeting these negative regulators with inhibitors. Although the results of at least some clinical trials of MDM2 inhibitors and mutant p53-restoring compounds are promising, none of the agents has yet been approved by the FDA. Alternative strategies, based on a better understanding of p53 biology, the mechanisms of action of compounds and treatment regimens as well as the development of new technologies are gaining interest, such as proteolysis-targeting chimeras for MDM2 degradation. Other approaches are taking advantage of the progress made in immune-based therapies for cancer. In this Review, we present these ongoing clinical trials and emerging approaches to re-evaluate the current state of knowledge of p53-based therapies for cancer.

Cell fate regulation governed by p53: Friends or reversible foes in cancer therapy

Cancer is a leading cause of death worldwide. Targeted therapies aimed at key oncogenic driver mutations in combination with chemotherapy and radiotherapy as well as immunotherapy have benefited cancer patients considerably. Tumor protein p53 (TP53), a crucial tumor suppressor gene encoding p53, regulates numerous downstream genes and cellular phenotypes in response to various stressors. The affected genes are involved in diverse processes, including cell cycle arrest, DNA repair, cellular senescence, metabolic homeostasis, apoptosis, and autophagy. However, accumulating recent studies have continued to reveal novel and unexpected functions of p53 in governing the fate of tumors, for example, functions in ferroptosis, immunity, the tumor microenvironment and microbiome metabolism. Among the possibilities, the evolutionary plasticity of p53 is the most controversial, partially due to the dizzying array of biological functions that have been attributed to different regulatory mechanisms of p53 signaling. Nearly 40 years after its discovery, this key tumor suppressor remains somewhat enigmatic. The intricate and diverse functions of p53 in regulating cell fate during cancer treatment are only the tip of the iceberg with respect to its equally complicated structural biology, which has been painstakingly revealed. Additionally, TP53 mutation is one of the most significant genetic alterations in cancer, contributing to rapid cancer cell growth and tumor progression. Here, we summarized recent advances that implicate altered p53 in modulating the response to various cancer therapies, including chemotherapy, radiotherapy, and immunotherapy. Furthermore, we also discussed potential strategies for targeting p53 as a therapeutic option for cancer.

Dual-sgRNA CRISPRa System for Enhanced MK-7 Production and Salmonella Infection Mitigation in Bacillus subtilis natto Applied to Caco-2 Cells

This study optimized the menaquinone-7 (MK-7) synthetic pathways in Bacillus subtilis (B. subtilis) natto NB205, a strain that originated from natto, to enhance its MK-7 production. Utilizing mutation breeding, we developed NBMK308, a mutant strain that demonstrated a significant 117.23% increase in MK-7 production. A comprehensive transcriptome analysis identified two key genes, ispA and ispE, as being critical in MK-7 synthesis. The dual-sgRNA CRISPRa system was utilized to achieve precise regulation of ispA and ispE in the newly engineered strain, A3E3. This strategic modulation resulted in a significant enhancement of MK-7 production, achieving increases of 20.02% and 201.41% compared to traditional overexpression systems and the original strain NB205, respectively. Furthermore, the fermentation supernatant from A3E3 notably inhibited Salmonella invasion in Caco-2 cells, showcasing its potential for combating such infections. The safety of the dual-sgRNA CRISPRa system was confirmed through cell assays. The utilization of the dual-sgRNA CRISPRa system in this study was crucial for the precise regulation of key genes in MK-7 synthesis, leading to a remarkable increase in production and demonstrating additional therapeutic potential in inhibiting pathogenic infections. This approach effectively combined the advantages of microbial fermentation and biotechnology, addressing health and nutritional challenges.

Mutational landscape of TP53 and CDH1 in gastric cancer

In this editorial we comment on an article published in a recent issue of the World J Gastrointest Surg. A common gene mutation in gastric cancer (GC) is the TP53 mutation. As a tumor suppressor gene, TP53 is implicated in more than half of all tumor occurrences. TP53 gene mutations in GC tissue may be related with clinical pathological aspects. The TP53 mutation arose late in the progression of GC and aided in the final switch to malignancy. CDH1 encodes E-cadherin, which is involved in cell-to-cell adhesion, epithelial structure maintenance, cell polarity, differentiation, and intracellular signaling pathway modulation. CDH1 mutations and functional loss can result in diffuse GC, and CDH1 mutations can serve as independent prognostic indicators for poor prognosis. GC patients can benefit from genetic counseling and testing for CDH1 mutations. Demethylation therapy may assist to postpone the onset and progression of GC. The investigation of TP53 and CDH1 gene mutations in GC allows for the investigation of the relationship between these two gene mutations, as well as providing some basis for evaluating the prognosis of GC patients.

New Phenolic Glycosides from Coelogyne fuscescens Lindl. var. brunnea and Their Cytotoxicity against Human Breast Cancer Cells

The phytochemical investigation of the whole plants of Coelogyne fuscescens Lindl. var. brunnea led to the discovery of three new phenolic glycosides, i.e., coelofusides A-C (1-3) and 12 known compounds (4-15). For the first time, we reported the nuclear magnetic resonance (NMR) data of 4-O-(6'-O-glucosyl-4″-hydroxybenzoyl)-4-hydroxybenzyl alcohol (4) in this study. The identification of the structures of newly discovered compounds was done through the analysis of their spectroscopic data [NMR, mass spectrometry, ultraviolet, Fourier transform infrared, optical rotation, and circular dichroism (CD)]. In comparison to anticancer drugs (i.e., etoposide and carboplatin), we evaluated anticancer potential of the isolated compounds on two different breast cancer cell lines, namely, T47D and MDA-MB-231. Human fibroblast HaCaT cells were used as the control cells. After a 48 h incubation, flavidin (8), coelonin (10), 3,4-dihydroxybenzaldehyde (11), and oxoflavidin (12) showed significant cytotoxic effects against breast cancer cells. Among them, oxoflavidin (12) exhibited the most potent cytotoxicity on MDA-MB-231 with an IC50 value of 26.26 ± 4.33 μM. In the nuclear staining assay, oxoflavidin induced apoptosis after 48 h in both T47D and MDA-MB-231 cells in a dose-dependent manner. Furthermore, oxoflavidin upregulated the expression of apoptotic genes, such as p53, Bax, poly(ADP-ribose) polymerase, caspase-3, and caspase-9 genes while significantly decreasing antiapoptotic protein (Bcl-2) expression levels.