Arsenic Trioxide Rescues Structural p53 Mutations through a Cryptic Allosteric Site

Design, synthesis, and activity evaluation of indole derivatives as potential stabilizers for p53 Y220C

The p53 Y220C mutation is frequently observed in human cancers. This mutation renders the p53 Y220C unstable at physiological temperatures, leading to a loss of its normal function and promoting tumor development. In this study, a total of eight compounds were designed and synthesized based on the active compound C8. The protein thermal shift assay revealed that both C8-3b and C8-6 exhibited similar activity of C8, with a ΔTm value of +0.5 °C. Compounds C8-1a, C8-1b, and C8-2b were found to enhance the thermostability of p53 Y220C (ΔTm: + 1.0 °C), the melting temperature exhibits an enhancement of 0.5 °C over the C8, indicating that these compounds possess the ability to stabilize p53 Y220C. The results of the cell viability assay revealed that C8-1b exhibited selective inhibitory effects on the proliferation of tumor cells harboring the p53 Y220C mutation. Furthermore, we utilized molecular docking and two-dimensional interaction analysis to elucidate the binding mode and key interactions of these compounds with p53 Y220C. Our study suggests that these compounds could potentially serve as lead compounds for enhancing the stability of p53 Y220C, thus providing a rational approach for designing small molecule stabilizers against p53 mutations.

Nuclear AGO2 supports influenza A virus replication through type-I interferon regulation

The role of Argonaute (AGO) proteins and the RNA interference (RNAi) machinery in mammalian antiviral response has been debated. Therefore, we set out to investigate how mammalian RNAi impacts influenza A virus (IAV) infection. We reveal that IAV infection triggers nuclear accumulation of AGO2, which is directly facilitated by p53 activation. Mechanistically, we show that IAV induces nuclear AGO2 targeting of TRIM71and type-I interferon-pathway genes for silencing. Accordingly, Tp53-/- mice do not accumulate nuclear AGO2 and demonstrate decreased susceptibility to IAV infection. Hence, the RNAi machinery is highjacked by the virus to evade the immune system and support viral replication. Furthermore, the FDA-approved drug, arsenic trioxide, prevents p53 nuclear translocation, increases interferon response and decreases viral replication in vitro and in a mouse model in vivo. Our data indicate that targeting the AGO2:p53-mediated silencing of innate immunity may offer a promising strategy to mitigate viral infections.

The outcast of medicine: metals in medicine--from traditional mineral medicine to metallodrugs

Metals have long held a significant role in the human body and have been utilized as mineral medicines for thousands of years. The modern advancement of metals in pharmacology, particularly as metallodrugs, has become crucial in disease treatment. As the machanism of metallodurgsare increasingly uncovered, some metallodrugs are already approved by FDA and widely used in treating antitumor, antidiabetes, and antibacterial. Therefore, a thorough understanding of metallodrug development is essential for advancing future study. This review offers an in-depth examination of the evolution of mineral medicines and the applications of metallodrugs within contemporary medicine. We specifically aim to summarize the historical trajectory of metals and mineral medicines in Traditional Chinese Mineral Medicine by analyzing key historical texts and representative mineral medicines. Additionally, we discuss recent advancements in understanding metallodrugs' mechanisms, such as protein interactions, enzyme inhibition, DNA interactions, reactive oxygen species (ROS) generation, and cellular structure targeting. Furthermore, we address the challenges in metallodrug development and propose potential solutions. Lastly, we outline future directions for metallodrugs to enhance their efficacy and effectiveness. The progression of metallodrugs has broadened their applications and contributed significantly to patient health, creating good healthcare solutions for the global population.

Phase Separation and Prion-Like Aggregation of p53 Family Tumor Suppressors: From Protein Evolution to Cancer Treatment

Biomolecular condensates, formed through phase separation (PS), are essential in various physiological processes, but they can also transition into amyloid-like structures, contributing to diseases like cancer and neurodegenerative disorders. This review centers on the tumor suppressor protein p53 and its paralogs, p63 and p73, which play significant roles in cancer biology. Mutations in the TP53 gene, present in over half of all malignant tumors, disrupt the function of p53 and contribute to cancer progression. Mutant p53 not only misfolds but also forms biomolecular condensates and amyloid-like aggregates, like the toxic amyloids seen in neurodegenerative diseases. These amyloid-like structures, characteristic of mutant p53, might be associated with its gain of function (GoF) in cancer. Recent in vitro and in cell studies demonstrate that mutant p53 can exert a prion-like effect on its paralogs, p63 and p73, which typically do not form amyloids under physiological conditions. Heparin inhibits the prion-like effect of mutant p53 on p63 and p73. These findings underscore the critical role of mutant p53 in promoting the aggregation of p63 and p73, and likely of other transcription factors, suggesting new therapeutic targets. The amyloid-like aggregation of mutant p53 is an excellent candidate target for cancer, as evidenced by recent studies. By understanding the phase transitions and amyloid formation of mutant p53, innovative diagnostic and treatment strategies have been explored to reveal and disrupt these processes, offering hope for improved cancer therapies.

Pharmacological rescue of mutant p53 triggers spontaneous tumor regression via immune responses

Tumor suppressor p53 is the most frequently mutated protein in cancer, possessing untapped immune-modulating capabilities in anticancer treatment. Here, we investigate the efficacy and underlying mechanisms of pharmacological reactivation of mutant p53 in treating spontaneous tumors in mice. In the p53 R279W (equivalent to the human hotspot R282W) mouse model developing spontaneous tumors, arsenic trioxide (ATO) treatment through drinking water significantly prolongs the survival of mice, dependent on p53-R279W reactivation. Transient regressions of spontaneous T-lymphomas are observed in 70% of the ATO-treated mice, accompanied by interferon (IFN) response. In allograft models, the tumor-suppressive effect of reactivated p53-R279W is detectably reduced in both immunodeficient Rag1-/- and CD8+ T cell-depleted mice. ATO also activates the IFN pathway in human cancer cells harboring various p53 mutations, as well as in primary samples derived from the p53-mutant patient treated with ATO. Together, p53 could serve as an alternative therapeutic target for the development of immunotherapies.

Pestones A and B from a Fungus Pestalotiopsis sp. Bound to Mutant p53 and Changed Its Conformation

Oncogenic mutant p53 is one of the targets for cancer therapy, and the development of anticancer drugs that reactivate mutant p53 is a promising strategy. The extract of fungus Pestalotiopsis sp. changed mutant p53 to wild-type-like p53 in Saos-2 (p53R175H) cells, as shown by fluorescent immunostaining, and bioassay-guided purification of the extract afforded new dimeric epoxyquinoids, pestones A and B (1 and 2), and a known compound, rosnecatrone (3). The relative and absolute configurations of 1 and 2 were determined based on the spectroscopic data and semisynthesis from 3. Compounds 1 and 2 altered the conformation of mutant p53 in Saos-2 (p53R175H) cells, as shown by immunofluorescence staining. The cellular thermal shift assay analysis showed that 1 increased the thermostability of mutant p53 in Saos-2 (p53R175H) cells, suggesting the direct binding of 1 to mutant p53. Compounds 1 and 2 exhibited cytotoxic activities against Saos-2 (p53R175H) cells with IC50 values of 1.0 and 1.1 μM, respectively. Compound 1 was found to induce apoptosis in Saos-2 (p53R175H) cells by flow cytometry analysis and decreased tumor growth in vivo using a mouse model with HuCCT1 (p53R175H) cells.

An FDA-approved drug structurally and phenotypically corrects the K210del mutation in genetic cardiomyopathy models

Dilated cardiomyopathy (DCM) due to genetic disorders results in decreased myocardial contractility, leading to high morbidity and mortality rates. There are several therapeutic challenges in treating DCM, including poor understanding of the underlying mechanism of impaired myocardial contractility and the difficulty of developing targeted therapies to reverse mutation-specific pathologies. In this report, we focused on K210del, a DCM-causing mutation, due to 3-nucleotide deletion of sarcomeric troponin T (TnnT), resulting in loss of Lysine210. We resolved the crystal structure of the troponin complex carrying the K210del mutation. K210del induced an allosteric shift in the troponin complex resulting in distortion of activation Ca2+-binding domain of troponin C (TnnC) at S69, resulting in calcium discoordination. Next, we adopted a structure-based drug repurposing approach to identify bisphosphonate risedronate as a potential structural corrector for the mutant troponin complex. Cocrystallization of risedronate with the mutant troponin complex restored the normal configuration of S69 and calcium coordination. Risedronate normalized force generation in K210del patient-induced pluripotent stem cell-derived (iPSC-derived) cardiomyocytes and improved calcium sensitivity in skinned papillary muscles isolated from K210del mice. Systemic administration of risedronate to K210del mice normalized left ventricular ejection fraction. Collectively, these results identify the structural basis for decreased calcium sensitivity in K210del and highlight structural and phenotypic correction as a potential therapeutic strategy in genetic cardiomyopathies.

Statins Diversity Revealed by the Deep-Sea-Derived Fungus Penicillium viridicatum

Seven new (1-7) and six known (8-13) statin derivatives were obtained from the deep-sea-derived fungus Penicillium viridicatum MCCC 3A00265. The structures assigned to the new compounds were based on a comprehensive analysis of the spectroscopic data, with absolute configurations established by Mosher analysis and biogenetic consideration. Most of the new compounds (1-5 and 7) share an octohydronaphthalene backbone, except that viridecalin F (6) possesses an uncommon naphthalene core. Viridecalins C (3) and F (6) and the two known compounds 9 and 11 exhibit considerable ability in reactivating mutant p53 protein at 10 μM, while viridecalin C showcases the most potent reactivation activity, indicating the potential of application in cancer therapy.

Quinazolinone nitriles and related metabolites from the deep-sea-derived fungus Penicillium viridicatum MCCC 3A00265

Two new quinazolinone nitriles (1 and 2) and one new indole alkaloid (3), together with 13 known compounds, were isolated from the deep-sea-derived Penicillium viridicatum MCCC 3A00265. Their structures were determined by extensive spectroscopic analysis, with the absolute configurations established by comparing experimental and calculated electronic circular dichroism (ECD) and optical rotation (OR) data as well as biogenetic considerations. Viricyanoamides A and B (1 and 2) are the sole representatives of quinazolinones featuring a nitrile group, while solitumidine F (3) incorporates a rare pyrrolidinedione unit as an indole terpenoid. In particular, compounds 2 and 10 exhibit significant activity in reactivating mutant p53 at 10 μM, indicating their potential for application in cancer therapy.

Targeting secretory autophagy in solid cancers: mechanisms, immune regulation and clinical insights

Secretory autophagy is a classical form of unconventional secretion that integrates autophagy with the secretory process, relying on highly conserved autophagy-related molecules and playing a critical role in tumor progression and treatment resistance. Traditional autophagy is responsible for degrading intracellular substances by fusing autophagosomes with lysosomes. However, secretory autophagy uses autophagy signaling to mediate the secretion of specific substances and regulate the tumor microenvironment (TME). Cytoplasmic substances are preferentially secreted rather than directed toward lysosomal degradation, involving various selective mechanisms. Moreover, substances released by secretory autophagy convey biological signals to the TME, inducing immune dysregulation and contributing to drug resistance. Therefore, elucidating the mechanisms underlying secretory autophagy is essential for improving clinical treatments. This review systematically summarizes current knowledge of secretory autophagy, from initiation to secretion, considering inter-tumor heterogeneity, explores its role across different tumor types. Furthermore, it proposes future research directions and highlights unresolved clinical challenges.

Modification Effects of Homologous Recombination Repair Gene Polymorphisms on the Associations Between Urinary Metals and Breast Cancer Risk

Metals are recognized as important factors related to breast cancer (BC) risk. Homologous recombination repair (HRR) genes might modify the toxicity of metals by influencing the distribution and metabolism of metal compounds. This study aims to investigate the modification effects of single nucleotide polymorphisms (SNPs) in HRR genes on the associations between urinary metals and BC risk. A total of 685 BC cases and 741 controls were recruited from October 2009 to December 2012. Twenty-one metals were analyzed in urine samples using inductively coupled plasma mass spectrometry (ICP-MS), and three SNPs (LIG3 rs1052536, RFC1 rs6829064, and RAD54L rs17102086) were genotyped. We identified significant interactions between four metals and two SNPs on the risk of BC. For LIG3 rs1052536 C/T variant, participants with CT/TT genotypes exposed to higher cobalt (Co) levels had higher BC risk compared to those with CC genotype (Pinteraction = 0.048). For RAD54L rs17102086 T/C variant, participants with TT genotype who were exposed to higher levels of zinc (Zn), Co, arsenic (As), and strontium (Sr) had more pronounced BC risk than the CC/TC genotypes (all Pinteraction < 0.05). This study showed compelling evidence for the interaction between genetic variants within the HRR system and urinary metals on BC risk. Our findings highlight the need to consider genetic makeup when evaluating the carcinogenic or protective potential of metals.

Reprogramming of Glucose Metabolism for Revisiting Hepatocellular Carcinoma Resistance to Transcatheter Hepatic Arterial Chemoembolization

Hepatocellular carcinoma (HCC) is recognized globally as one of the most lethal tumors, presenting a significant menace to patients' lives owing to its exceptional aggressiveness and tendency to recur. Transcatheter hepatic arterial chemoembolization (TACE) therapy, as a first-line treatment option for patients with advanced HCC, has been proven effective. However, it is disheartening that nearly 40 % of patients exhibit resistance to this therapy. Consequently, this review delves into the metabolic aspects of glucose metabolism to explore the underlying mechanisms behind TACE treatment resistance and to propose potentially fruitful therapeutic strategies. The ultimate objective is to present novel insights for the development of personalized treatment methods targeting HCC.

Heavy metals: toxicity and human health effects

Heavy metals are naturally occurring components of the Earth's crust and persistent environmental pollutants. Human exposure to heavy metals occurs via various pathways, including inhalation of air/dust particles, ingesting contaminated water or soil, or through the food chain. Their bioaccumulation may lead to diverse toxic effects affecting different body tissues and organ systems. The toxicity of heavy metals depends on the properties of the given metal, dose, route, duration of exposure (acute or chronic), and  extent of bioaccumulation. The detrimental impacts of heavy metals on human health are largely linked to their capacity to interfere with antioxidant defense mechanisms, primarily through their interaction with intracellular glutathione (GSH) or sulfhydryl groups (R-SH) of antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and other enzyme systems. Although arsenic (As) is believed to bind directly to critical thiols, alternative hydrogen peroxide production processes have also been postulated. Heavy metals are known to interfere with signaling pathways and affect a variety of cellular processes, including cell growth, proliferation, survival, metabolism, and apoptosis. For example, cadmium can affect the BLC-2 family of proteins involved in mitochondrial death via the overexpression of antiapoptotic Bcl-2 and the suppression of proapoptotic (BAX, BAK) mechanisms, thus increasing the resistance of various cells to undergo malignant transformation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of antioxidant enzymes, the level of oxidative stress, and cellular resistance to oxidants and has been shown to act as a double-edged sword in response to arsenic-induced oxidative stress. Another mechanism of significant health threats and heavy metal (e.g., Pb) toxicity involves the substitution of essential metals (e.g., calcium (Ca), copper (Cu), and iron (Fe)) with structurally similar heavy metals (e.g., cadmium (Cd) and lead (Pb)) in the metal-binding sites of proteins. Displaced essential redox metals (copper, iron, manganese) from their natural metal-binding sites can catalyze the decomposition of hydrogen peroxide via the Fenton reaction and generate damaging ROS such as hydroxyl radicals, causing damage to lipids, proteins, and DNA. Conversely, some heavy metals, such as cadmium, can suppress the synthesis of nitric oxide radical (NO·), manifested by altered vasorelaxation and, consequently, blood pressure regulation. Pb-induced oxidative stress has been shown to be indirectly responsible for the depletion of nitric oxide due to its interaction with superoxide radical (O2·-), resulting in the formation of a potent biological oxidant, peroxynitrite (ONOO-). This review comprehensively discusses the mechanisms of heavy metal toxicity and their health effects. Aluminum (Al), cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), and chromium (Cr) and their roles in the development of gastrointestinal, pulmonary, kidney, reproductive, neurodegenerative (Alzheimer's and Parkinson's diseases), cardiovascular, and cancer (e.g. renal, lung, skin, stomach) diseases are discussed. A short account is devoted to the detoxification of heavy metals by chelation via the use of ethylenediaminetetraacetic acid (EDTA), dimercaprol (BAL), 2,3-dimercaptosuccinic acid (DMSA), 2,3-dimercapto-1-propane sulfonic acid (DMPS), and penicillamine chelators.

TP53 gene status can promote sensitivity and resistance to chemotherapeutic drugs and small molecule signal transduction inhibitors

TP53 is normally a tumor suppressor. However, it is mutated in at least 50% of human cancers. Usually, we assume that mutation of the TP53 is associated with loss of sensitivity to various drugs as in most cases wild type (WT) TP53 activity is lost. This type of mutations is often dominant-negative (DN) mutations as they can interfere with the normal functions of WT-TP53 which acts as a tetramer. These mutations can result in altered gene expression patterns. There are some TP53 mutations which may lack some of the normal functions of TP53 but have additional functions; these types of mutations are called gain of function (GOF) mutations. There is another class of TP53 mutations, they are TP53 null mutations as the cells have deleted the TP53 gene (TP53-null). Although TP53 mutations were initially considered undruggable, other approaches have been developed to increase TP53 activity. One approach was to develop mouse double minute 2 homolog (MDM2) inhibitors as MDM2 suppresses TP53 activity. In addition, there have been mutant TP53 reactivators created, which will at least partially restore some of the critical growth suppressing effects of TP53. Some of these mutant TP53 reactivators have shown promise in clinical trial in certain types of cancer patients, especially myelodysplastic syndrome (MDS). In this review, we summarize the development of novel TP53 reactivators and MDM2 inhibitors. Both approaches are aimed at increasing or restoring TP53 activity. Attempts to increase TP53 activity in various TP53 mutant tumors could increase therapy of multiple deadly diseases.

Deep CRISPR mutagenesis characterizes the functional diversity of TP53 mutations

The mutational landscape of TP53, a tumor suppressor mutated in about half of all cancers, includes over 2,000 known missense mutations. To fully leverage TP53 mutation status for personalized medicine, a thorough understanding of the functional diversity of these mutations is essential. We conducted a deep mutational scan using saturation genome editing with CRISPR-mediated homology-directed repair to engineer 9,225 TP53 variants in cancer cells. This high-resolution approach, covering 94.5% of all cancer-associated TP53 missense mutations, precisely mapped the impact of individual mutations on tumor cell fitness, surpassing previous deep mutational scan studies in distinguishing benign from pathogenic variants. Our results revealed even subtle loss-of-function phenotypes and identified promising mutants for pharmacological reactivation. Moreover, we uncovered the roles of splicing alterations and nonsense-mediated messenger RNA decay in mutation-driven TP53 dysfunction. These findings underscore the power of saturation genome editing in advancing clinical TP53 variant interpretation for genetic counseling and personalized cancer therapy.

Mechanisms of p53 core tetramer stability mediated by multi-interface interactions: A molecular dynamics study

p53 is a tumor suppressor protein for impeding cancer development and maintaining genetic integrity. The formation of the p53 core tetramer is regulated by multiple cooperative interaction interfaces. To investigate the internal mechanisms of tetramer stability, we performed all-atom molecular dynamics simulations. Our findings indicate that the symmetric interface maintains highly conserved interactions, while the dimer-dimer interface displays notable flexibility. Additionally, we identified a novel salt bridge at the dimer-dimer interface that significantly contributes to the interaction energy. Moreover, the affinity of p53 for DNA is more than twice that of protein-protein interactions, driven primarily by five key residues that form multiple hydrogen bonds. Through independent simulations of the two dimeric models, we provide a theoretical explanation for why only the symmetric dimeric structure has been observed experimentally. The study identifies key regions and residues that contribute to stability at the inter-molecular interaction interfaces within the p53 tetramer, and highlight the important roles of each contact surface in the formation and stability of the tetramer.

Harnessing Arsenic Derivatives and Natural Agents for Enhanced Glioblastoma Therapy

Glioblastoma (GBM) is the most common and lethal intracranial tumor in adults. Despite advances in the understanding of the molecular events responsible for disease development and progression, survival rates and mortality statistics for GBM patients have been virtually unchanged for decades and chemotherapeutic drugs used to treat GBM are limited. Arsenic derivatives, known as highly effective anticancer agents for leukemia therapy, has been demonstrated to exhibit cytocidal effects toward GBM cells by inducing cell death, cell cycle arrest, inhibition of migration/invasion, and angiogenesis. Differentiation induction of glioma stem-like cells (GSCs) and inhibition of neurosphere formation have also been attributed to the cytotoxicity of arsenic derivatives. Intriguingly, similar cytotoxic effects against GBM cells and GSCs have also been observed in natural agents such as anthocyanidins, tetrandrine, and bufadienolides. In the current review, we highlight the available data on the molecular mechanisms underlying the multifaceted anticancer activity of arsenic compounds and natural agents against cancer cells, especially focusing on GBM cells and GCSs. We also outline possible strategies for developing anticancer therapy by combining natural agents and arsenic compounds, as well as temozolomide, an alkylating agent used to treat GBM, in terms of improvement of chemotherapy sensitivity and minimization of side effects.

Essential thrombocytosis transformed AML with TP53 mutations and its clinical implications

Essential thrombocytosis (ET) is a chronic myeloproliferative neoplasm. There is a rare possibility of its transformation from ET into acute myeloid leukemia (AML). While the TP53 mutation is a well-known risk factor for AML, limited research exists regarding ET patients who develop AML with TP53 mutations. Among three ET transformed AML patients, two exhibited TP53 mutations, with an increased number of AML cells. Conversely, the third ET patient who transformed to AML without TP53 mutations had a lower burden of AML cells. The patients with TP53 mutations had shorter survival times compared to that without mutations, in response to decitabine treatment. In contrast, the patient with ET transformed AML without TP53 mutations showed a better response to decitabine. The ET transformed AML without TP53 mutations patient exhibited a survival period exceeding 20 months. ET patients who develop AML with a high allelic burden of TP53 mutations may experience a more aggressive disease progression and severe complications compared to AML patient without TP53 mutations. Our report sheds light on the distinct clinical presentations of ET patients who develop AML, characterized by different TP53 mutations and varying therapeutic outcomes when treated with decitabine. However, further studies that include a larger quantity of samples are needed to elucidate the precise underlying molecular mechanisms involved in this process.

Mutant p53-Mediated Tumor Secretome: Bridging Tumor Cells and Stromal Cells

The tumor secretome comprises the totality of protein factors secreted by various cell components within the tumor microenvironment, serving as the primary medium for signal transduction between tumor cells and between tumor cells and stromal cells. The deletion or mutation of the p53 gene leads to alterations in cellular secretion characteristics, contributing to the construction of the tumor microenvironment in a cell non-autonomous manner. This review discusses the critical roles of mutant p53 in regulating the tumor secretome to remodel the tumor microenvironment, drive tumor progression, and influence the plasticity of cancer-associated fibroblasts (CAFs) as well as the dynamics of tumor immunity by focusing on both secreted protein expression and secretion pathways. The aim is to provide new insights for targeted cancer therapies.

Synthesis and structural characterization of the heavy tricysteinylpnictines, models of protein-bound As(III), Sb(III), and Bi(III)

The heavier group 15 elements As, Sb, and Bi are more restricted in their biochemistry than the nearly ubiquitous lighter congeners N and P, but organisms do encounter compounds of these elements as environmental toxins, starting materials for secondary metabolite biosynthesis, substrates for primary metabolism, or exogenously applied medicines. Under many physiological conditions, these compounds are transformed into pnictogen(III) species, the soft Lewis acidic character of which leads them to interact strongly with biologically relevant soft Lewis bases such as small-molecule thiols or cysteine residues of proteins and peptides. The archetypal complexes As(Cys)3, Sb(Cys)3, and Bi(Cys)3 have been studied in the past but a lack of detailed information about their molecular structures has hampered the analysis of protein structures featuring As(III), Sb(III), and Bi(III) bound to cysteine thiolate residues. In many cases, the formation of such protein adducts is proposed to play a key role in the mechanism of action of inorganic drugs that feature these elements. Here, we refine synthetic strategies to access As(Cys)3, Sb(Cys)3, and Bi(Cys)3, describe their crystal structures, analyze structural trends across the series and across Pn(SR)3 compounds deposited in the Cambridge Structural Database, and compare their features to the structures of proteins with these centers bound to Cys3 motifs. Significant differences were noted for many of the protein structures.

Unraveling the Guardian: p53's Multifaceted Role in the DNA Damage Response and Tumor Treatment Strategies

DNA damage can lead to mutations that can alter the function of oncogenes or tumor suppressor genes, thus promoting the development of cancer. p53 plays a multifaceted and complex role in the DNA damage response and cancer progression and is known as the 'guardian of the gene'. When DNA damage occurs, p53 is activated through a series of post-translational modifications, which stabilize the protein and enhance its function as a transcription factor. It regulates processes including cell cycle checkpoints, DNA repair and apoptosis, thereby preventing the spread of damaged DNA and maintaining genome integrity. On the one hand, p53 can initiate cell cycle arrest and induce cells to enter the G1/S and G2/M checkpoints, preventing cells with damaged DNA from continuing to proliferate and gaining time for DNA repair. At the same time, p53 can promote the activation of DNA repair pathways, including base excision repair, nucleotide excision repair and other repair pathways, to ensure the integrity of genetic material. If the damage is too severe to repair, p53 will trigger the apoptosis process to eliminate potential cancer risks in time. p53 also plays a pivotal role in cancer progression. Mutations in the p53 gene are frequently found in many cancers, and the mutated p53 not only loses its normal tumor suppressor function but may even acquire pro-cancer activity. Therefore, we also discuss therapeutic strategies targeting the p53 pathway, such as the use of small-molecule drugs to restore the function of wild-type p53, the inhibition of negative regulatory factors and synthetic lethality approaches for p53-deficient tumors. This review therefore highlights the important role of p53 in maintaining genomic stability and its potential in therapeutic strategies for cancer.

Case report: TP53 c.848G>A germline mutation as a possible screening target at initial diagnosis for acute lymphoblastic leukemia

BACKGROUD

Li-Fraumeni syndrome is a hereditary tumor syndrome characterized by an elevated risk of malignancy, particularly acute lymphoblastic leukemia (ALL), which can be caused by the heterozygous germline mutation. TP53 gene germline mutation is considered a potential risk factor and crucial prognostic parameter for acute leukemia development and diagnosis, but rarely occurs in adults, and its specific pathogenic significance in acute leukemia is unclear.

CASE PRESENTATION

We describes a case of a 45-year-old woman diagnosed with ALL. Whole-exome sequencing approach identified one of the TP53 germline mutations from her bone marrow sample with possible pathogenic significance, c.848G>A (p.Arg283His) heterozygous missense mutation located on exon 8, which was further verified in her hair, oral mucous and nail samples. Family pedigree screening revealed that the same TP53 genetic variant was present in the patient's father and non-donor son, whereas not in the donor. Digital PCR observed that this point mutation frequency dropped post-transplantation but remained low during maintenance therapy when the patient was leukemia-free.

CONCLUSION

This suspected Li-Fraumeni syndrome case report with a likely pathogenic heterozygous TP53 variant expands the cancer genetic spectrum. Screening her family members for mutations facilitates identifying the optimal relative donor and avoids unnecessary treatment by monitoring TP53 germline mutations for minimal residual disease following hematopoietic stem cell transplantation. Its potential roles in hematological malignant tumor development and clinical pathogenic implications necessitate further probing.

Necroptosis and autophagy in cisplatinum-triggered nephrotoxicity: Novel insights regarding their prognostic and diagnostic potential

Necroptosis is an innovative class of programmed autophagy (Atg) and necrosis; considered as a type of homeostatic housekeeping machinery that have observed an escalating concern due to its power in alleviating Cisplatinum-induced nephrotoxicity. This article elucidated in details the prospective role of both autophagy and necroptosis on Cisplatinum-triggered nephrotoxicity and investigating more potent therapy via lactoferrin and Ti-NPS conjugation. Cisplatinum is a commonly used chemotherapeutic drug; one of the limiting adverse actions of cisplatinum is renal toxicity. Upon cisplatinum administration, autophagy is highly stimulated in the kidney to shield against nephrotoxicity. Atg is a lysosomal degradation process which discards detorirated proteins to retain cell homeostasis. This article summarizes necroptosis progress in reconizing cisplatinum nephrotoxicity and debates how this progress can help in discovering more potent therapy via lactoferrin and Ti-NPS conjugation via monitoring autophagy and apoptotic biomarkers X-box-binding protein 1 (XBP), C/EBP homologous protein (CHOP), hypoxanthine phosphoribosyltransferase-1 (HPRT), FKBP prolyl isomerase 1B (FKBP), Cellular myelocytomatosis oncogene (C-myc), tumor suppressor gene (P53) and tumor necrosis factor (TNF-α). Cisplatinum nephrotoxicity was conducted in rat model via an oral dose of (2 mg/kg BW) for one month furthermore a comparative study was conducted among TiNPs-loaded Cisplatinum and Lactoferrin loaded Cisplatinum. Loaded drug delivery system counteracted Cisplatinum triggered nephrotoxicity via controlling autophagy and apoptotic XBP, CHOP, HPRT, FKBP, C-myc, P53 and TNF-α signaling pathway.

Development of Oral, Potent, and Selective CK1α Degraders for AML Therapy

Molecular glue degraders (MGDs) are proximity-inducing agents that mediate the cooperative interaction between a target protein and an E3 ligase, introducing an additional layer of specificity beyond that afforded by traditional small molecules. Historically, molecular glues that stabilize protein-protein interactions were often discovered serendipitously. In this study, we leveraged the reprogramming potential of cereblon (CRBN)-based ligands and conducted a CRBN-dependent proliferation screen to identify CRBN-based MGDs capable of inducing the degradation of proteins essential for cell viability. Through our screening and subsequent medicinal chemistry optimization, we identified dCK1α-1 as a potent and selective CK1α-targeting molecular glue degrader. Furthermore, we synthesized an orally active derivative, dCK1α-2, with enhanced pharmacokinetic properties, which exhibited pronounced degradation activity and demonstrated efficacy in mouse models following oral gavage. These findings indicate that phenotypic drug discovery campaigns, in combination with chemically distinct CRBN ligand libraries, can accelerate the development of therapeutically relevant MGDs. Furthermore, the development of dCK1α-1 and dCK1α-2 provides new therapeutic options for cancers with functional p53 signaling and offers valuable chemical tools for future investigations into the role of CK1α.

From regulation to deregulation of p53 in hematologic malignancies: implications for diagnosis, prognosis and therapy

The p53 protein, encoded by the TP53 gene, serves as a critical tumor suppressor, playing a vital role in maintaining genomic stability and regulating cellular responses to stress. Dysregulation of p53 is frequently observed in hematological malignancies, significantly impacting disease progression and patient outcomes. This review aims to examine the regulatory mechanisms of p53, the implications of TP53 mutations in various hematological cancers, and emerging therapeutic strategies targeting p53. We conducted a comprehensive literature review to synthesize recent findings related to p53's multifaceted role in hematologic cancers, focusing on its regulatory pathways and therapeutic potential. TP53 mutations in hematological malignancies often lead to treatment resistance and poor prognosis. Current therapeutic strategies, including p53 reactivation and gene therapy, show promise in improving treatment outcomes. Understanding the intricacies of p53 regulation and the consequences of its mutations is essential for developing effective diagnostic and therapeutic strategies in hematological malignancies, ultimately enhancing patient care and survival.

Designed Cell-Penetrating Peptide Constructs for Inhibition of Pathogenic Protein Self-Assembly

Peptides possess a number of pharmacologically desirable properties, including greater chemical diversity than other biomolecule classes and the ability to selectively bind to specific targets with high potency, as well as biocompatibility, biodegradability, and ease and low cost of production. Consequently, there has been considerable interest in developing peptide-based therapeutics, including amyloid inhibitors. However, a major hindrance to the successful therapeutic application of peptides is their poor delivery to target tissues, cells or subcellular organelles. To overcome these issues, recent efforts have focused on engineering cell-penetrating peptide (CPP) antagonists of amyloidogenesis, which combine the attractive intrinsic properties of peptides with potent therapeutic effects (i.e., inhibition of amyloid formation and the associated cytotoxicity) and highly efficient delivery (to target tissue, cells, and organelles). This review highlights some promising CPP constructs designed to target amyloid aggregation associated with a diverse range of disorders, including Alzheimer's disease, transmissible spongiform encephalopathies (or prion diseases), Parkinson's disease, and cancer.

Drugging p53: Barriers, Criteria, and Prospects

Pharmacologically targeting tumor suppressors necessitates an unprecedented strategy of restoring, rather than conventionally inhibiting, protein function, and p53, the most commonly mutated protein in cancer, has thus remained undruggable. In this study, we address long-standing misconceptions in the field and gaps in the scientific logic for a p53 function-restoration strategy, identify four barriers for drugging mutant p53, and accordingly propose effectiveness evaluation criteria, clinical-translating norms, and prospects for mutant p53 rescue compounds.

Synergistic rescue of temperature-sensitive p53 mutants by hypothermia and arsenic trioxide

The p53 tumor suppressor is inactivated by mutations in about 50% of tumors. Rescuing the transcriptional function of mutant p53 has potential therapeutic benefits. Approximately 15% of p53 mutants are temperature sensitive (TS) and regain maximal activity at 32°C. Proof of concept study showed that induction of 32°C hypothermia in mice restored TS mutant p53 activity and inhibited tumor growth. However, 32°C is the lower limit of therapeutic hypothermia procedures for humans. Higher temperatures are preferable but result in suboptimal TS p53 activation. Recently, arsenic trioxide (ATO) was shown to rescue the conformation of p53 structural mutants by stabilizing the DNA binding domain. We examined the responses of 17 frequently observed p53 TS mutants to functional rescue by temperature shift and ATO. The results showed that ATO only rescued mild p53 TS mutants with high basal activity at 37°C. Mild TS mutants showed a common feature of regaining significant activity at the semi-permissive temperature of 35°C and could be further stimulated by ATO at 35°C. TS p53 rescue by ATO was antagonized by the cellular redox mechanism and was rapidly reversible. Inhibition of glutathione (GSH) biosynthesis enhanced ATO rescue efficiency and sustained p53 activity after ATO washout. The results suggest that mild TS p53 mutants are uniquely responsive to functional rescue by ATO due to small thermostability deficits and inherent potential to regain active conformation. Combining mild hypothermia and ATO may provide an effective and safe procedure for targeting tumors with p53 TS mutations.

Study on the Hepatotoxicity of Emodin and Its Application in the Treatment of Liver Fibrosis

Emodin (EMO) is an anthraquinone compound derived from Rheum palmatum L., which has rich pharmacological activity. However, studies have shown that EMO may cause hepatotoxicity. In this study, EMO was combined with tetrandrine and prepared as lipid nanoparticles (E-T/LNPs). The anti-liver fibrosis activity of EMO before and after formulation was evaluated by zebrafish and mice. In addition, the toxicity of EMO and E-T/LNPs was compared and the toxicity-efficacy concentrations of E-T/LNPs in zebrafish were verified. E-T/LNPs are morphologically stable (particle size within 100 nm), have high encapsulation efficiency and good stability, and are capable of long-lasting slow release in vitro. The combination and preparation can reduce the toxicity and enhance the effect of EMO, and increase the toxicity and effect concentration of E-T/LNPs in vivo. In a short period, low doses of E-T/LNPs can be used for the treatment of liver fibrosis; high doses of E-T/LNPs cause toxicity in vivo. Immunohistochemistry showed that E-T/LNPs inhibited hepatic fibrosis by downregulating the levels of IL-1β and TGF-β. Based on the advantages of combination therapy and nanotechnology, it can play a role in reducing the toxicity and increasing the efficacy of EMO in the treatment of liver fibrosis.

Mechanisms and therapeutic target of anti-tumour treatment-related Ferroptosis: How to improve cancer therapy?

Recently, increased attention has been focused on the regulatory mechanism and potential clinical application of ferroptosis in cancer cells, especially therapy-related ferroptosis. However, the mechanism of treatment-related ferroptosis and the application prospects and strategies for future treatment still require further clarification. This review highlights the molecular relationships between different clinical antitumour drugs, including commonly used chemotherapy drugs, radiation therapy and vitamins, and ferroptosis. This review also proposes strategies for future treatments that involve ferroptosis, with an aim to develop a new strategy for the transformative potential of the emerging field of ferroptosis to improve cancer therapy.

Salvage chemotherapy regimens with arsenic trioxide for relapsed or refractory neuroblastoma: a promising approach

In patients with relapsed or refractory neuroblastoma (NB), the limited efficacy of conventional chemotherapies necessitates the exploration of new treatment options. Previous studies have highlighted the anti-tumor properties of arsenic trioxide (ATO) in high-risk NB (HR-NB). This study aims to assess the effectiveness and safety of ATO combined with salvage chemotherapy regimens, featuring cyclophosphamide and topotecan, as a foundational treatment for children with relapsed or refractory NB. Eleven patients (four relapsed, seven refractory NB) were retrospectively analyzed for efficacy and treatment relevance. Salvage treatments, incorporating ATO (0.18 mg/kg daily for 8 h intravenously on days 1 to 10), were administered upon disease progression or relapse, with assessments conducted every two cycles. Treatments had 63.6% efficacy, with six cases of partial response, one case of stable disease, and four cases of disease progression. The overall response rate was 54.5%, and the disease control rate was 63.6%. Importantly, the systemic toxicity experienced by patients following salvage chemotherapy with ATO was mild. Salvage chemotherapy regimens featuring ATO demonstrated potential for prolonging disease stabilization for relapsed or refractory HR-NB patients, exhibiting both favorable efficacy and safety profiles. This suggests further clinical exploration and promotion of this therapeutic approach in the treatment of NB.

p53-Mediated Mitochondrial Translocation of EI24 Triggered by ER Stress Plays an Important Role in Arsenic-Induced Liver Damage via Activating Mitochondrial Apoptotic Pathway

Chronic arsenic poisoning is a public health problem worldwide. In addition to skin lesions, the detrimental effect of arsenic poisoning on liver damage is one of the major issues. Our previous studies demonstrated that endoplasmic reticulum (ER) stress and p53 were associated with arsenic-induced liver damage. Literature has shown that EI24 is involved in hepatocyte hypertrophy; however, the underlying role and mechanism in arsenic-induced liver damage have not been fully elucidated. In this study, we explored the role of ER stress, p53, and EI24 as well as the regulatory relationship in arsenic poisoning populations and L-02 cells treated with distinct concentration NaAsO2 (2.5, 5, 10, and 20 μM). Results showed that as with arsenic dose increment, expression levels of ER stress key proteins GRP78, ATF4, and CHOP were significantly enhanced. Additionally, p53 expression in nucleus, p53 phosphorylation at Ser15 and Ser1392, and p53 acetylation at lys382 were significantly increased in NaAsO2-treated L-02 cells. ER stress inhibitor 4-phenylbutyric acid (4-PBA) decreased the expression of p53 phosphorylation at Ser 392, p53 acetylation at lys382, and p53 expression in nucleus. Additionally, in 5 μM NaAsO2 condition, p53 inhibitor pifithrin-α (PFT-α) aggravated 5 μM NaAsO2-induced GRP78, ATF4, and CHOP expressions, cell apoptosis, and protein-SH consumption. But in 20 μM NaAsO2 condition, PFT-α attenuated NaAsO2-induced cell apoptosis. Further results showed that 20 μM NaAsO2 facilitated translocation of EI24 from ER to mitochondrion and interaction with VDAC2, leading to activate mitochondrial apoptotic pathway, but not observed in the 5-μM NaAsO2 group. Moreover, PFT-α and 4-PBA inhibited 20 μM NaAsO2-induced EI24 expression in mitochondrion. Collectively, our results indicated that arsenic induced p53 activation via ER stress, under relatively low NaAsO2 concentration, NaAsO2-triggered p53 activation protected cells from apoptosis by alleviating ER stress. Another finding was that under relatively high NaAsO2 concentration, NaAsO2-activated p53 facilitated EI24 mitochondrial translocation and caused mitochondrial permeability increase, which represented a switch of p53 from a benefit role to pro-apoptosis function in NaAsO2-treated cells. The study contributed to in-depth understanding the mechanism of arsenic-induced liver damage and providing potential clues for following study.

The value of protein allostery in rational anticancer drug design: an update

INTRODUCTION

Allosteric drugs are advantageous. However, they still face hurdles, including identification of allosteric sites that will effectively alter the active site. Current strategies largely focus on identifying pockets away from the active sites into which the allosteric ligand will dock and do not account for exactly how the active site is altered. Favorable allosteric inhibitors dock into sites that are nearby the active sites and follow nature, mimicking diverse allosteric regulation strategies.

AREAS COVERED

The following article underscores the immense significance of allostery in drug design, describes current allosteric strategies, and especially offers a direction going forward. The article concludes with the authors' expert perspectives on the subject.

EXPERT OPINION

To select a productive venue in allosteric inhibitor development, we should learn from nature. Currently, useful strategies follow this route. Consider, for example, the mechanisms exploited in relieving autoinhibition and in harnessing allosteric degraders. Mimicking compensatory, or rescue mutations may also fall into such a thesis, as can molecular glues that capture features of scaffolding proteins. Capturing nature and creatively tailoring its mimicry can continue to innovate allosteric drug discovery.

Pyrimidine Triones as Potential Activators of p53 Mutants

p53 is a crucial tumor suppressor in vertebrates that is frequently mutated in human cancers. Most mutations are missense mutations that render p53 inactive in suppressing tumor initiation and progression. Developing small-molecule drugs to convert mutant p53 into an active, wild-type-like conformation is a significant focus for personalized cancer therapy. Prior research indicates that reactivating p53 suppresses cancer cell proliferation and tumor growth in animal models. Early clinical evidence with a compound selectively targeting p53 mutants with substitutions of tyrosine 220 suggests potential therapeutic benefits of reactivating p53 in patients. This study identifies and examines the UCI-1001 compound series as a potential corrector for several p53 mutations. The findings indicate that UCI-1001 treatment in p53 mutant cancer cell lines inhibits growth and reinstates wild-type p53 activities, including DNA binding, target gene activation, and induction of cell death. Cellular thermal shift assays, conformation-specific immunofluorescence staining, and differential scanning fluorometry suggest that UCI-1001 interacts with and alters the conformation of mutant p53 in cancer cells. These initial results identify pyrimidine trione derivatives of the UCI-1001 series as candidates for p53 corrector drug development.

Targeting mutant p53 with arsenic trioxide: A preclinical study focusing on triple negative breast cancer

New treatments are urgently required for triple-negative breast cancer (TNBC). As TP53 is mutated in approximately 80% of TNBC, it is theoretically an attractive target for new drugs for this disease. Arsenic trioxide (ATO), which is used to treat promyelocytic leukaemia, was recently shown to reactivate mutant p53 and restore wild-type functionality. The aim of this study was to evaluate ATO as a potential new treatment for TNBC. Using a panel of 20 cell lines, we found that TNBC cell lines were more sensitive to ATO than non-TNBC cell lines (P = 0.045). Consistent with its ability to reactivate mutant p53, ATO was a more potent inhibitor of proliferation in cell lines with mutant TP53 than the wildtype TP53 (P = 0.027). Direct evidence of mutant p53 reactivation was the induction of multiple wild-type p53 canonical target genes such as CDKN1A, SLC7A11, BBC3, PMAIP1, SESN2, SRXN1 and TXNRD1. Our findings support the activation of mutant p53 by ATO and, furthermore, the possible repurposing of ATO to treat TP53-mutated TNBC.

Oncogenic R248W mutation induced conformational perturbation of the p53 core domain and the structural protection by proteomimetic amyloid inhibitor ADH-6

The involvement of p53 aggregation in cancer pathogenesis emphasizes the importance of unraveling the mechanisms underlying mutation-induced p53 destabilization. And understanding how small molecule inhibitors prevent the conversion of p53 into aggregation-primed conformations is pivotal for the development of therapeutics targeting p53-aggregation-associated cancers. A recent experimental study highlights the efficacy of the proteomimetic amyloid inhibitor ADH-6 in stabilizing R248W p53 and inhibiting its aggregation in cancer cells by interacting with the p53 core domain (p53C). However, it remains mostly unclear how R248W mutation induces destabilization of p53C and how ADH-6 stabilizes this p53C mutant and inhibits its aggregation. Herein, we conducted all-atom molecular dynamics simulations of R248W p53C in the absence and presence of ADH-6, as well as that of wild-type (WT) p53C. Our simulations reveal that the R248W mutation results in a shift of helix H2 and β-hairpin S2-S2' towards the mutation site, leading to the destruction of their neighboring β-sheet structure. This further facilitates the formation of a cavity in the hydrophobic core, and reduces the stability of the β-sandwich. Importantly, two crucial aggregation-prone regions (APRs) S9 and S10 are disturbed and more exposed to solvent in R248W p53C, which is conducive to p53C aggregation. Intriguingly, ADH-6 dynamically binds to the mutation site and multiple destabilized regions in R248W p53C, partially inhibiting the shift of helix H2 and β-hairpin S2-S2', thus preventing the disruption of the β-sheets and the formation of the cavity. ADH-6 also reduces the solvent exposure of APRs S9 and S10, which disfavors the aggregation of R248W p53C. Moreover, ADH-6 can preserve the WT-like dynamical network of R248W p53C. Our study elucidates the mechanisms underlying the oncogenic R248W mutation induced p53C destabilization and the structural protection of p53C by ADH-6.

An engineered DNA aptamer-based PROTAC for precise therapy of p53-R175H hotspot mutant-driven cancer

Targeting oncogenic mutant p53 represents an attractive strategy for cancer treatment due to the high frequency of gain-of-function mutations and ectopic expression in various cancer types. Despite extensive efforts, the absence of a druggable active site for small molecules has rendered these mutants therapeutically non-actionable. Here we develop a selective and effective proteolysis-targeting chimera (PROTAC) for p53-R175H, a common hotspot mutant with dominant-negative and oncogenic activity. Using a novel iterative molecular docking-guided post-SELEX (systematic evolution of ligands by exponential enrichment) approach, we rationally engineer a high-performance DNA aptamer with improved affinity and specificity for p53-R175H. Leveraging this resulting aptamer as a binder for PROTACs, we successfully developed a selective p53-R175H degrader, named dp53m. dp53m induces the ubiquitin-proteasome-dependent degradation of p53-R175H while sparing wildtype p53. Importantly, dp53m demonstrates significant antitumor efficacy in p53-R175H-driven cancer cells both in vitro and in vivo, without toxicity. Moreover, dp53m significantly and synergistically improves the sensitivity of these cells to cisplatin, a commonly used chemotherapy drug. These findings provide evidence of the potential therapeutic value of dp53m in p53-R175H-driven cancers.

DNA-delivered monoclonal antibodies targeting the p53 R175H mutant epitope inhibit tumor development in mice

The tumor suppressor p53 is the most common mutated gene in cancer, with the R175H as the most frequent p53 missense mutant. However, there are currently no approved targeted therapies or immunotherapies against mutant p53. Here, we characterized and investigated a monoclonal antibody (mAb) that recognizes the mutant p53-R175H for its affinity, specificity, and activity against tumor cells in vitro. We then delivered DNA plasmids expressing the anti-R175H mAb or a bispecific antibody (BsAb) into mice to evaluate their therapeutic effects. Our results showed that the anti-R175H mAb specifically bound to the p53-R175H antigen with a high affinity and recognized the human mutant p53-R175H antigen expressed on HEK293T or MC38 cells, with no cross-reactivity with wild-type p53. In cultured cells, the anti-R175H mAb showed higher cytotoxicity than the control but did not induce antibody-dependent cellular cytotoxicity. We made a recombinant MC38 mouse cell line (MC38-p53-R175H) that overexpressed the human p53-R175H after knocking out the endogenous mutant p53 alleles. In vivo, administration of the anti-R175H mAb plasmid elicited a robust anti-tumor effect against MC38-p53-R175H in mice. The administration of the anti-R175H BsAb plasmid showed no therapeutic effects, yet potent anti-tumor activity was observed in combination with the anti-PD-1 antibody. These results indicate that targeting specific mutant epitopes using DNA-delivered mAbs or BsAbs presents a form of improved natural immunity derived from tumor-infiltrating B cells and plasma cells against intracellular tumor antigens.

Design and Synthesis of Thiourea-Conjugating Organic Arsenic D-Glucose with Anticancer Activities

Organic arsenic compounds such as p-aminophenylarsine oxide (p-APAO) are easier for structural optimization to improve drug-like properties such as pharmacokinetic properties, therapeutic efficacy, and target selectivity. In order to strengthen the selectivity of 4-(1,3,2-dithiarsinan-2-yl) aniline 7 to tumor cell, a thiourea moiety was used to strengthen the anticancer activity. To avoid forming a mixture of α/β anomers, the strategy of 2-acetyl's neighboring group participation was used to lock the configuration of 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate from 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide. 1-(4-(1,3,2-dithiarsinan-2-yl) aniline)-2-N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranos-1-yl)-thiourea 2 can increase the selectivity of human colon cancer cells HCT-116 (0.82 ± 0.06 μM vs. 1.82 ± 0.07 μM) to human embryonic kidney 293T cells (1.38 ± 0.01 μM vs. 1.22 ± 0.06 μM) from 0.67 to 1.68, suggesting a feasible approach to improve the therapeutic index of arsenic-containing compounds as chemotherapeutic agents.

Structural basis of p53 inactivation by cavity-creating cancer mutations and its implications for the development of mutant p53 reactivators

The cavity-creating p53 cancer mutation Y220C is an ideal paradigm for developing small-molecule drugs based on protein stabilization. Here, we have systematically analyzed the structural and stability effects of all oncogenic Tyr-to-Cys mutations (Y126C, Y163C, Y205C, Y220C, Y234C, and Y236C) in the p53 DNA-binding domain (DBD). They were all highly destabilizing, drastically lowering the melting temperature of the protein by 8-17 °C. In contrast, two non-cancerous mutations, Y103C and Y107C, had only a moderate effect on protein stability. Differential stabilization of the mutants upon treatment with the anticancer agent arsenic trioxide and stibogluconate revealed an interesting proximity effect. Crystallographic studies complemented by MD simulations showed that two of the mutations, Y234C and Y236C, create internal cavities of different size and shape, whereas the others induce unique surface lesions. The mutation-induced pockets in the Y126C and Y205C mutant were, however, relatively small compared with that of the already druggable Y220C mutant. Intriguingly, our structural studies suggest a pronounced plasticity of the mutation-induced pocket in the frequently occurring Y163C mutant, which may be exploited for the development of small-molecule stabilizers. We point out general principles for reactivating thermolabile cancer mutants and highlight special cases where mutant-specific drugs are needed for the pharmacological rescue of p53 function in tumors.

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.

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.

PML restrains p53 activity and cellular senescence in clear cell renal cell carcinoma

Clear-cell renal cell carcinoma (ccRCC), the major subtype of RCC, is frequently diagnosed at late/metastatic stage with 13% 5-year disease-free survival. Functional inactivation of the wild-type p53 protein is implicated in ccRCC therapy resistance, but the detailed mechanisms of p53 malfunction are still poorly characterized. Thus, a better understanding of the mechanisms of disease progression and therapy resistance is required. Here, we report a novel ccRCC dependence on the promyelocytic leukemia (PML) protein. We show that PML is overexpressed in ccRCC and that PML depletion inhibits cell proliferation and relieves pathologic features of anaplastic disease in vivo. Mechanistically, PML loss unleashed p53-dependent cellular senescence thus depicting a novel regulatory axis to limit p53 activity and senescence in ccRCC. Treatment with the FDA-approved PML inhibitor arsenic trioxide induced PML degradation and p53 accumulation and inhibited ccRCC expansion in vitro and in vivo. Therefore, by defining non-oncogene addiction to the PML gene, our work uncovers a novel ccRCC vulnerability and lays the foundation for repurposing an available pharmacological intervention to restore p53 function and chemosensitivity.

Influence of TP53 mutation on efficacy and survival in advanced EGFR-mutant non-small cell lung cancer patients treated with third-generation EGFR tyrosine kinase inhibitors

TP53 comutation is related to poor prognosis of non-small cell lung cancer. However, there is limited study focusing on the structural influence of TP53 mutation on third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. We retrospectively analyzed the clinical and molecular data of patients treated with third-generation EGFR-TKIs in two independent cohorts. A total of 117 patients from the Sun Yat-sen University Cancer Center (SYSUCC) and 141 patients from the American Association for Cancer Research Project GENIE database were included. In the SYSUCC cohort, TP53 comutations were found in 59 patients (50.4%) and were associated with poor median progress-free survival (mPFS) and median overall survival (mOS). The additional subtype analysis found that TP53 mutation in the alpha-helix region had shorter mOS compared with those with TP53 mutations in other regions in the SYSUCC cohort (mOS, 12.2 vs. 21.7 months; p = 0.027). Similar findings were confirmed in the GENIE cohort. Specifically, the presence of TP53 mutation in the alpha-helix region was an independent negative predictive factor for PFS [hazard ratio (HR) 2.05(1.01-4.18), p = 0.048] and OS [HR 3.62(1.60-8.17), p = 0.002] in the SYSUCC cohort. TP53 mutation in alpha-helix region was related to inferior clinical outcomes in patients treated with third-generation EGFR-TKIs.

TP53 in MDS and AML: Biological and clinical advances

Recently, the WHO-5 and the ICC 2022 criteria have emphasized poor prognosis in AML/MDS patients with multi-hit TP53 mutations, whereas mutated TP53 plays a critical role in tumorigenesis, drawing substantial interest in exploring its biological behaviors. Diverse characteristics of TP53 mutations, including types, VAF, CNVs, allelic status, karyotypes, and concurrent mutations have been extensively studied. Novel potential targets and comprehensive treatment strategies nowadays are under swift development, owing to great advances in technology. However, accurately predicting prognosis of patients with TP53-mutated myeloid neoplasms remains challenging. And there is still a lack of effective treatment for those patients.

Hepatocellular Carcinoma: Current Drug Therapeutic Status, Advances and Challenges

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, accounting for ~90% of liver neoplasms. It is the second leading cause of cancer-related deaths and the seventh most common cancer worldwide. Although there have been rapid developments in the treatment of HCC over the past decade, the incidence and mortality rates of HCC remain a challenge. With the widespread use of the hepatitis B vaccine and antiviral therapy, the etiology of HCC is shifting more toward metabolic-associated steatohepatitis (MASH). Early-stage HCC can be treated with potentially curative strategies such as surgical resection, liver transplantation, and radiofrequency ablation, improving long-term survival. However, most HCC patients, when diagnosed, are already in the intermediate or advanced stages. Molecular targeted therapy, followed by immune checkpoint inhibitor immunotherapy, has been a revolution in HCC systemic treatment. Systemic treatment of HCC especially for patients with compromised liver function is still a challenge due to a significant resistance to immune checkpoint blockade, tumor heterogeneity, lack of oncogenic addiction, and lack of effective predictive and therapeutic biomarkers.

Reinvent Aliphatic Arsenicals as Reversible Covalent Warheads toward Targeted Kinase Inhibition and Non-acute Promyelocytic Leukemia Cancer Treatment

The success of arsenic in acute promyelocytic leukemia (APL) treatment is hardly transferred to non-APL cancers, mainly due to the low selectivity and weak binding affinity of traditional arsenicals to oncoproteins critical for cancer survival. We present herein the reinvention of aliphatic trivalent arsenicals (As) as reversible covalent warheads of As-based targeting inhibitors toward Bruton's tyrosine kinase (BTK). The effects of As warheads' valency, thiol protection, methylation, spacer length, and size on inhibitors' activity were studied. We found that, in contrast to the bulky and rigid aromatic As warhead, the flexible aliphatic As warheads were well compatible with the well-optimized guiding group to achieve nanomolar inhibition against BTK. The optimized As inhibitors effectively blocked the BTK-mediated oncogenic signaling pathway, leading to elevated antiproliferative activities toward lymphoma cells and xenograft tumor. Our study provides a promising strategy enabling rational design of new aliphatic arsenic-based reversible covalent inhibitors toward non-APL cancer treatment.

Decitabine induces IRF7-mediated immune responses in p53-mutated triple-negative breast cancer: a clinical and translational study

p53 is mutated in half of cancer cases. However, no p53-targeting drugs have been approved. Here, we reposition decitabine for triple-negative breast cancer (TNBC), a subtype with frequent p53 mutations and extremely poor prognosis. In a retrospective study on tissue microarrays with 132 TNBC cases, DNMT1 overexpression was associated with p53 mutations (P = 0.037) and poor overall survival (OS) (P = 0.010). In a prospective DEciTabinE and Carboplatin in TNBC (DETECT) trial (NCT03295552), decitabine with carboplatin produced an objective response rate (ORR) of 42% in 12 patients with stage IV TNBC. Among the 9 trialed patients with available TP53 sequencing results, the 6 patients with p53 mutations had higher ORR (3/6 vs. 0/3) and better OS (16.0 vs. 4.0 months) than the patients with wild-type p53. In a mechanistic study, isogenic TNBC cell lines harboring DETECT-derived p53 mutations exhibited higher DNMT1 expression and decitabine sensitivity than the cell line with wild-type p53. In the DETECT trial, decitabine induced strong immune responses featuring the striking upregulation of the innate immune player IRF7 in the p53-mutated TNBC cell line (upregulation by 16-fold) and the most responsive patient with TNBC. Our integrative studies reveal the potential of repurposing decitabine for the treatment of p53-mutated TNBC and suggest IRF7 as a potential biomarker for decitabine-based treatments.