Cell Triggering Research Articles

Comparison of Different Keratinocyte Cell Line Models for Analysis of NLRP1 Inflammasome Activation

The NLRP1 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-1) inflammasome is the most important inflammasome in human keratinocytes. It plays a crucial role in regulating innate immunity in the skin. This study aimed to evaluate NLRP1 inflammasome activation and the corresponding levels of detection in different keratinocyte cell lines to identify a suitable in vitro model for analyzing inflammasome activation in keratinocytes. We compared NLRP1 inflammasome activation, expression, and cell death among primary keratinocytes and immortalized keratinocyte cell lines HaCaT, HaSKpw, and SVTERT upon stimulation with ultraviolet B (UVB) irradiation or talabostat. The effects of both NLRP1 inducers on cell death and the modification of NLRP1 molecules were examined using fluorescence-activated cell sorting analysis, Western blotting, and an enzyme-linked immunosorbent assay. The key inflammasome components had varied expression levels among the keratinocyte cell models, with the highest expression observed in primary keratinocytes. Moreover, our data showed that both UVB and talabostat triggered cell death, and NLRP1 inflammasome activation was readily detected in primary keratinocytes but not in the analyzed immortalized keratinocyte cell lines. Therefore, we do not recommend the use of the immortalized keratinocyte cell lines HaCaT, HaSKpw, and SVTERT for analyzing inflammasome activation in keratinocytes; we strongly recommend the use of primary keratinocytes for these studies.

Transient HR enhancement by RAD51-stimulatory compound confers protection on intestinal rather than hematopoietic tissue against irradiation in mice

DNA double-strand breaks (DSBs) are cytotoxic lesions that compromise genomic integrity and trigger cell death. Homologous recombination (HR) is a major pathway for repairing DSBs in cycling cells. However, it remains unclear whether transient modulation of HR could confer protection to adult stem cells against lethal irradiation exposure. In this study, we investigated the radio-protective effect of the RAD51-stimulatory compound RS-1 on adult stem cells and progenitor cells with varying cycling rates in intestinal and hematopoietic tissues. Treatment with RS-1 even at high doses did not induce noticeable cell death or proliferation of intestinal crypt cells in vivo. Pretreatment with RS-1 before irradiation significantly decreased mitotic death, promoted DNA repair and enhanced the survival of intestinal stem cells and progenitor cells and increased the number of regenerative crypt colonies thereby mitigating IR-induced gastrointestinal syndrome. Moreover, RS1 pretreatment could increase the survival and regeneration of irradiated intestinal organoid in vitro, which can be rescued by RAD51 inhibitor. However, pretreatment with RS-1 in vivo did not elevate nucleated cell count or HSPCs in bone marrow after 6Gy irradiation. Additionally, there was no impact on mouse survival due to drug treatment observed. Thus, our data suggest that targeting HR as a strategy to prevent tissue damage from acute irradiation exposure may depend on cell cycling rates and intrinsic DNA repair mechanisms.

Recognition of a salivary effector by the TNL protein RCSP promotes effector-triggered immunity and systemic resistance in Nicotiana benthamiana.

Insects secret chemosensory proteins (CSPs) into plant cells as potential effector proteins during feeding. The molecular mechanisms underlying how CSPs activate plant immunity remain largely unknown. We show that CSPs from six distinct insect orders induce dwarfism when overexpressed in Nicotiana benthamiana. Agrobacterium-mediated transient expression of Nilaparvata lugens CSP11 (NlCSP11) triggered cell death and plant dwarfism, both of which were dependent on ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), neuregulin 1 (NRG1) and SENESCENCE-ASSOCIATED GENE 101 (SAG101), indicating the activation of effector-triggered immunity (ETI) in N. benthamiana. Overexpression of NlCSP11 led to stronger systemic resistance against Pseudomonas syringae DC3000 lacking effector HopQ1-1 and tobacco mosaic virus, and induced higher accumulation of salicylic acid (SA) in uninfiltrated leaves compared to another effector XopQ that is recognized by a Toll-interleukin-1 receptor (TIR) domain nucleotide-binding leucine-rich repeat receptor (TNL) called ROQ1 in N. benthamiana. Consistently, NlCSP11-induced dwarfism and systemic resistance, but not cell death, were abolished in N. benthamiana transgenic line expressing the SA-degrading enzyme NahG. Through large-scale virus-induced gene silencing screening, we identified a TNL protein that mediates the recognition of CSPs (RCSP), including aphid effector MP10 that triggers resistance against aphids in N. benthamiana. Co-immunoprecipitation, bimolecular fluorescence complementation and AlphaFold2 prediction unveiled an interaction between NlCSP11 and RCSP. Interestingly, RCSP does not contain the conserved catalytic glutamic acid in the TIR domain, which is required for TNL function. Our findings point to enhanced ETI and systemic resistance by a TNL protein via hyperactivation of the SA pathway. Moreover, RCSP is the first TNL identified to recognize an insect effector.

Oxidative stress mechanism by gold compounds: a close look at total ROS increase and the inhibition of antioxidant enzymes.

The antitumor activity of various gold compounds is a promising field of investigation, attracting researchers seeking potential clinical candidates. To advance this research, they explore the complex mechanisms of action of these compounds. Since the discovery of the strong inhibition of thioredoxin reductase by auranofin, the primary mechanism explored has been the inhibition of this enzyme. This inhibition disrupts the redox balance in cells, promoting oxidative stress and triggering cell death. In this review, we analyzed studies from the past decade that measured cellular ROS increase and examined the coordination structures of gold compounds. We also correlate ROS increase with the inhibition of redox-regulating enzymes, thioredoxin reductase and glutathione reductase, to elucidate the relationship between these cellular effects and chemical structures. Our data compilation reveals that different structures exhibit varying efficacy: some significantly increase ROS production and inhibit thioredoxin reductase or glutathione reductase, while others elevate ROS levels without affecting these target enzymes, suggesting alternative mechanisms of action. This review consolidates critical evidence, enhancing our understanding of the mechanisms by which these gold complexes act and providing valuable insights for developing new therapeutic strategies against tumor cells.

AN ATYPICAL E3 LIGASE SAFEGUARDS THE RIBOSOME DURING NUTRIENT STRESS.

Metabolic stress must be effectively mitigated for the survival of cells and organisms. Ribosomes have emerged as signaling hubs that sense metabolic perturbations and coordinate responses that either restore homeostasis or trigger cell death. As yet, the mechanisms governing these cell fate decisions are not well understood. Here, we report an unexpected role for the atypical E3 ligase HOIL-1 in safeguarding the ribosome. We find HOIL-1 mutations associated with cardiomyopathy broadly sensitize cells to nutrient and translational stress. These signals converge on the ribotoxic stress sentinel ZAKα. Mechanistically, mutant HOIL-1 excludes a ribosome quality control E3 ligase from its functional complex and remodels the ribosome ubiquitin landscape. This quality control failure renders glucose starvation ribotoxic, precipitating a ZAKα-ATF4-xCT-driven noncanonical cell death. We further show HOIL-1 loss exacerbates cardiac dysfunction under pressure overload. These data reveal an unrecognized ribosome signaling axis and a molecular circuit controlling cell fate during nutrient stress.

Tetramerization-dependent activation of the Sir2-associated short prokaryotic Argonaute immune system

Eukaryotic Argonaute proteins (eAgos) utilize short nucleic acid guides to target complementary sequences for RNA silencing, while prokaryotic Agos (pAgos) provide immunity against invading plasmids or bacteriophages. The Sir2-domain associated short pAgo (SPARSA) immune system defends against invaders by depleting NAD+ and triggering cell death. However, the molecular mechanism underlying SPARSA activation remains unknown. Here, we present cryo-EM structures of inactive monomeric, active tetrameric and active NAD+-bound tetrameric SPARSA complexes, elucidating mechanisms underlying SPARSA assembly, guide RNA preference, target ssDNA-triggered SPARSA tetramerization, and tetrameric-dependent NADase activation. Short pAgos form heterodimers with Sir2-APAZ, favoring short guide RNA with a 5′-AU from ColE-like plasmids. RNA-guided recognition of the target ssDNA triggers SPARSA tetramerization via pAgo- and Sir2-mediated interactions. The resulting tetrameric Sir2 rearrangement aligns catalytic residue H186 for NAD+ hydrolysis. These insights advance our understanding of Sir2-domain associated pAgos immune systems and should facilitate the development of a short pAgo-associated biotechnological toolbox.

Lung‐Targeted Lipid Nanoparticle‐Delivered siUSP33 Attenuates SARS‐CoV‐2 Replication and Virulence by Promoting Envelope Degradation

AbstractAs a structural protein of SARS‐CoV‐2, the envelope (E) protein not only plays a key role in the formation of viral particles, but also forms ion channels and has pathogenic functions, including triggering cell death and inflammatory responses. The stability of E proteins is controlled by the host ubiquitin‐proteasome system. By screening human deubiquitinases, it is found that ubiquitin‐specific protease 33 (USP33) can enhance the stability of E proteins depending on its deubiquitinase activity, thereby promoting viral replication. In the absence of USP33, E proteins are rapidly degraded, leading to a reduced viral load and inflammation. Using lipid nanoparticle (LNP) encapsulation of siUSP33 by adjusting the lipid components (ionizable cationic lipids), siUSP33 is successfully delivered to mouse lung tissues, rapidly reducing USP33 expression in the lungs and maintaining knockdown for at least 14 days, effectively suppressing viral replication and virulence. This method of delivery allows efficient targeting of the lungs and a response to acute infections without long‐term USP33 deficiency. This research, based on the deubiquitination mechanism of USP33 on the E protein, demonstrates that LNP‐mediated siRNA delivery targeting USP33 plays a role in antiviral and anti‐inflammatory responses, offering a novel strategy for the prevention and treatment of SARS‐CoV‐2.

Exosomal miR-142-3p from M1-polarized macrophages suppresses cell growth and immune escape in glioblastoma through regulating HMGB1-mediated PD-1/PD-L1 checkpoint.

Glioblastoma (GBM) is one of the most prevalent cancerous brain tumors. Former studies have reported that exosomes derived from M1-polarized macrophages (M1 exosomes) inhibit tumor occurrence and development through delivery of tumor suppressor genes. Also, microRNA-142-3p (miR-142-3p) has been verified to function as a tumor suppressor. GBM cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8), colony formation assay and 5-ethynyl-2'-deoxyuridine (EdU) assay; cell apoptosis was determined by flow cytometry analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Mechanism investigations were conducted for analyzing the molecular mechanism by which miR-142-3p and M1 exosomes affect GBM progression. Upregulation of miR-142-3p expression was detected in M1-polarized macrophages and M1 exosomes. M1 exosomes inhibit GBM cell proliferation and trigger cell apoptosis. Functionally, miR-142-3p silencing promotes the proliferation and inhibits the apoptosis of GBM cells treated with M1 exosomes. As for molecular mechanism, miR-142-3p inhibits GBM cell growth via targeting high-mobility group box1 (HMGB1). In addition, miR-142-3p/HMGB1 axis affects GBM cell immune escape through modulation of programmed death-1/programmed death ligand-1 (PD-1/PD-L1) checkpoint. Our study demonstrated that exosomal miR-142-3p from M1-polarized macrophages suppresses cell growth and immune escape in GBM through regulating HMGB1-mediated PD-1/PD-L1 checkpoint.

Novel inhibitors of bromodomain and extra-terminal domain trigger cell death in breast cancer cell lines

Small molecule inhibitors targeting the bromodomain and extra-terminal domain (BET) family proteins have emerged as a promising class of anti-cancer drugs. Nevertheless, the clinical advancement of these agents has been significantly hampered by challenges related to their potency, oral bioavailability, or toxicity. In this study, virtual screening approaches were employed to discover novel inhibitors of the bromodomain-containing protein 4 (BRD4) by analyzing their comparable chemical structural features to established BRD4 inhibitors. Several of these compounds exhibited inhibitory effects on BRD4 activity ranging from 60 % to 70 % at 100 µM concentrations, while one compound also exhibited an 84 % inhibition of Sirtuin 2 (SIRT2) activity. Furthermore, a subset of structurally diverse compounds from the BRD4 inhibitors was selected to investigate their anti-cancer properties in both 2D and 3D cell cultures. These compounds exhibited varying effects on cell numbers depending on the specific cell line, and some of them induced cell cycle arrest in the G0/G1 phase in breast cancer (MDA-MB-231) cells. Moreover, all the compounds studied reduced the sizes of spheroids, and the most potent compound exhibited a 90 % decrease in growth at a concentration of 10 µM in T47D cells. These compounds hold potential as epigenetic regulators for future studies.

Application of external voltage-applied enhances surface adhesion of Shewanella oneidensis MR-1

Electroactive bacteria play a crucial role in electrocatalytic oxidation and reduction reactions within bioelectrochemical systems (BES). However, the influence of BES startup modes on the adhesion of electroactive bacteria and the underlying mechanisms remains elusive. We hypothesize that startup mode-induced microniches trigger changes in bacterial motility, which mediate bacterial adhesion on anodic surface. To test this hypothesis, we employed Shewanella oneidensis MR-1 as a model strain and launched investigations in single-chambered BES under both external voltage-free (EVF) and external voltage-applied (EVA) modes. Our results showed that the EVA mode facilitated MR-1 adhesion up to fourfold compared to the EVF mode. Surface chemistry analysis revealed that EVA mode, with proper external voltages (400–600 mV), enhanced substrate adsorption onto anodic surfaces by up to 410 %, significantly promoting bacterial cell movement and chemotactic migration towards anodic surfaces, thereby facilitating bacterial adhesion. Principal component analysis and structural equation modeling indicated that lactate adsorption capacity was the determining factor for bacterial adhesion under EVF mode, whereas external voltage diminished the effect of lactate on triggering cell motility and subsequent bacterial adhesion in the EVA mode. Our findings provide valuable insights into the initiation and enhancement of electrochemically active biofilm on electrode surfaces in BES.

Transcriptome analysis provides new insight into the mechanism of Bombyx mori under zinc exposure

Zinc is a significant source of heavy metal pollution that poses risks to both human health and biodiversity. Excessive concentrations of zinc can hinder the growth and development of insects and trigger cell death through oxidative damage. The midgut is the main organ affected by exposure to heavy metals. The silkworm, a prominent insect species belonging to the Lepidoptera class and widely used in China, serves as a model for studying the genetic response to heavy metal stress. In this study, high-throughput sequencing technology was employed to investigate detoxification-related genes in the midgut that are induced by zinc exposure. A total of 11,320 unigenes and 14,723 transcripts were identified, with 553 differentially expressed genes (DEGs) detected, among which 394 were up-regulated and 159 were down-regulated. The Gene Ontology (GO) analysis revealed that 452 DEGs were involved in 18 biological process subclasses, 14 cellular component subclasses and 8 molecular functional subclasses. Furthermore, the KEGG analysis demonstrated enrichment in pathways such as Protein digestion, absorption and Lysosome. Validation of the expression levels of 9 detoxification-related DEGs through qRT-PCR confirmed the accuracy of the RNA-seq results. This study not only contributes new insights into the detoxification mechanisms mechanism of silkworms against zinc contamination, but also serves as a foundation basis for understanding the molecular detoxification processes in lepidopteran insects.

Kigelia pinnata fruit extract mediated green synthesis of Ce11O20/CeCu/CuO nanocomposites and their anticancer and antibacterial properties

In the current study, we used green synthesis techniques to conjugate additional metals into native nanoparticles, with an emphasis on how this altered its surface morphology and biological capabilities. It is an important turning point in the field of nanotechnology since it opens up new, dependable, environmentally friendly and manageable ways to prepare nanocomposites. This work employs a green synthetic technique to synthesize CuO nanparticles (KpCuO NPs), Ce11O20/CeCu/CuO nanocomposites (KpCe@CuO-5 and KpCe@CuO-10 NCs) using aqueous extract of Kigelia pinnata fruit. The materials were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), surface area and porosity of nanocomposites analyzed with the Scanning Electronic Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), UV-visible spectroscopy (UV–visible), X-ray Powder Diffraction (XDR), XPS (X-ray photoelectron spectroscopy), and High-Resolution Transmission Electron Microscopy (HRTEM). The synthesized KpCuO NPs, KpCe@CuO-5 and KpCe@CuO-10 nanocomposites exhibited anticancerous activity against MDA-MB-231, HEK-293 and antimicrobial properties against E. Coli bacteria. These samples also demonstrated their bio-potency by preventing the migration and proliferation of cells, decreasing the number of colonies, and triggering cell cycle arrest and programmed cell death. All of these findings suggest that KpCuO NPs and KpCe@CuO NCs have therapeutic potential to treat triple negative breast cancer (TNBC).

CGAS-activated endothelial cell-T cell cross-talk initiates tertiary lymphoid structure formation.

Aberrant activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway causes autoimmunity in humans and mice; however, the exact mechanism by which the cGAS-STING pathway initiates adaptive immunity and tissue pathology is still not fully understood. Here, we used a cGAS knockin (KI) mouse model that develops systemic autoimmunity. In the lungs of cGAS-KI mice, blood vessels were enclosed by organized lymphoid tissues that resemble tertiary lymphoid structures (TLSs). Cell-intrinsic cGAS induction promoted up-regulation of CCR5 in CD8+ T cells and led to CCL5 production in vascular endothelial cells. Peripheral CD8+ T cells were recruited to the lungs and produced CXCL13 and interferon-γ. The latter triggered endothelial cell death, potentiated CCL5 production, and was essential for TLS establishment. Blocking CCL5 or CCR5, or depleting CD8+ T cells, impaired TLS formation. cGAS-mediated TLS formation also enhanced humoral and antitumor responses. These data demonstrate that cGAS signaling drives a specialized lymphoid structure that underlies autoimmune tissue pathology.

Characterization of Clostridioides difficile Persister Cells and Their Role in Antibiotic Tolerance.

Clostridioides difficile is a Gram-positive pathogen known for its toxin production and spore formation. It is primarily responsible for most cases of antibiotic-associated diarrhea. Bacterial persisters are a small subset of the population that exhibits transient tolerance to bactericidal substances, and they are of significant medical concern due to their association with the emergence of antibiotic resistance and difficult-to-treat chronic or recurrent infections. Vancomycin, the predominant antibiotic utilized in the management of C. difficile infection, is extensively applied in the realm of clinical practice. Previous studies have demonstrated a persister-like phenotype with treatments involving this antibiotic. However, the mechanism in C. difficile remains largely unknown, primarily due to the challenge of isolating this small population at any given time. To better characterize C. difficile persister cells, we present a study that enables the enrichment and characterization of persister cells from bacterial cultures in both the exponential and stationary phases. Moreover, we could differentiate between triggered (induced using antibiotics such as vancomycin) and spontaneous (stochastic) persister cells. Additionally, we observed the involvement of toxin-antitoxin systems and Clp proteases in persister cell formation.

Regulation of RIPK1 Phosphorylation: Implications for Inflammation, Cell Death, and Therapeutic Interventions.

Receptor-interacting protein kinase 1 (RIPK1) plays a crucial role in controlling inflammation and cell death. Its function is tightly controlled through post-translational modifications, enabling its dynamic switch between promoting cell survival and triggering cell death. Phosphorylation of RIPK1 at various sites serves as a critical mechanism for regulating its activity, exerting either activating or inhibitory effects. Perturbations in RIPK1 phosphorylation status have profound implications for the development of severe inflammatory diseases in humans. This review explores the intricate regulation of RIPK1 phosphorylation and dephosphorylation and highlights the potential of targeting RIPK1 phosphorylation as a promising therapeutic strategy for mitigating human diseases.

A prognostic impact of interleukin 32 (IL-32) as an immune marker in patients with bladder cancer

Background. Urinary bladder cancer is a prevalent global health concern. IL-32 is a cytokine that promotes inflammation and has been shown in multiple studies to suppress the development of cancer cells and trigger cell death in different types of cancer cells. Materials and methods. Expression of 32 interleukins was determined using an immunohistochemistry technique, which uses analysis of the exact concentrations and locations of specific compounds in tissues. This is done by using antibodies (antibodies) that react with the target protein (in this case IL-32), then identifying the sites where the active protein is located. The study included 114 diagnosed bladder cancer samples and 10 healthy controls. Results. By analyzing the expression of IL-32 using IHC technology on both bladder tissue from cancer patients and healthy bladder tissue that was considered a control, the results of evaluating IL-32 levels in bladder tissue from cancer patients showed a high level. Conclusion. High levels of IL-32 indicate disease progression or a poor outcome, while low levels can indicate an improvement or a good outcome. This is consistent with the fundamental aim of this study: the possibility of using IL-32 as a diagnostic or prognostic marker for disease progression and outcome prediction in cancer patients.

Physicochemical Properties of Different Sulfated Polysaccharide Components from Laetiporus sulphureus and Their Anti-Proliferative Effects on MDA-MB-231 Breast Cancer Cells.

Laetiporus sulphureus is an edible and medicinal mushroom widely used in folk medicine for treating cancer and gastric diseases. This study aimed to investigate the physicochemical properties of different sulfated polysaccharide (SPS) components (F1, F2, and F3) isolated from L. sulphureus and evaluate their activity against MDA-MB-231 breast cancer cell proliferation. Compared with F1 and F3, the results showed that F2 exhibited the most potent anti-proliferative activity on MDA-MB-231 cells, which could be attributed to the sulfate and protein contents, molecular weight, and monosaccharide composition. F2 inhibited breast cancer cell proliferation by blocking the cell cycle at the G0/G1 phase but not triggering cell apoptosis. In addition, F2 also showed selective cytotoxicity on breast cancer cells. It modulated the expression of proteins involved in G0/G1 phase progression, cell cycle checkpoints, DNA replication, and the TGFβ signaling pathway in MDA-MB-231 cells. This study demonstrated that F2, the medium-molecular-weight SPS component of L. sulphureus, possessed the most potent inhibitory effect on MDA-MB-231 cell proliferation by arresting the cell cycle at the G0/G1 phase. The main factors contributing to the differences in the potency of anti-breast cancer activity between F1, F2, and F3 could be the sulfate and protein contents, molecular weight, and monosaccharide composition of SPS.

A comprehensive review of soybean RNL and TIR domain proteins.

Both prokaryotic and eukaryotic organisms use the nucleotide-binding domain/leucine-rich repeat (NBD/LRR)-triggered immunity (NLR-triggered immunity) signaling pathway to defend against pathogens. Plant NLRs are intracellular immune receptors that can bind to effector proteins secreted by pathogens. Dicotyledonous plants express a type of NLR known as TIR domain-containing NLRs (TNLs). TIR domains are enzymes that catalyze the production of small molecules that are essential for immune signaling and lead to plant cell death. The activation of downstream TNL signaling components, such as enhanced disease susceptibility 1 (EDS1), phytoalexin deficient 4 (PAD4), and senescence-associated gene 101 (SAG101), is facilitated by these small molecules. Helper NLRs (hNLRs) and the EDS1-PAD4/SAG101 complex associate after activation, causing the hNLRs to oligomerize, translocate to the plasma membrane (PM), and produce cation-selective channels. According to a recent theory, cations enter cells through pores created by oligomeric hNLRs and trigger cell death. Occasionally, TNLs can self-associate to create higher-order oligomers. Here, we categorized soybean TNLs based on the protein domains that they possess. We believe that TNLs may help soybean plants effectively fight pathogens by acting as a source of genetic resistance. In summary, the purpose of this review is to elucidate the range of TNLs that are expressed in soybean.

Exploring the Pharmacological Potential of Chlorogenic acid as an Anti-Cancer Agent and a Call for Advance Research.

Chlorogenic acid (CHA) is a phenolic substance found in various edible plants, such as tea and green coffee extracts. This chemical has demonstrated significant efficacy in reducing the probability of many diseases in preclinical and clinical environments. Chlorogenic acid (CHA) possesses several pharmacological attributes, such as anticancer, hepatoprotective, antimicrobial, immune-suppressant, antioxidant, and antidiabetic activities. Its applications extend to multiple industries, such as food, chemicals, medicine, and healthcare. Studies have shown that CHA can exert its anticancer effects through numerous mechanisms. It can hinder the process of cell division, trigger cell apoptosis, and suppress an increase in cancerous cell growth. The literature research conducted for this study revealed a variety of molecular and cellular processes influencing distinct signaling pathways. These mechanisms include angiogenesis, invasion and migration, oxidative stress, inflammation, cell cycle arrest, and proliferation.However, significant issues surround the use of CHA, primarily due to its limited bioavailability in animal models. This review focuses on the chemistry, natural sources, pharmacokinetics, and underlying mechanisms of action of CHA and its clinical utility in treating life-threatening diseases, such as cancer. The manuscript provides insight into novel formulation approaches.

APR-246 as a radiosensitization strategy for mutant p53 cancers treated with alpha-particles-based radiotherapy

Radiation therapy (RT) remains a common treatment for cancer patients worldwide, despite the development of targeted biological compounds and immunotherapeutic drugs. The challenge in RT lies in delivering a lethal dose to the cancerous site while sparing the surrounding healthy tissues. Low linear energy transfer (low-LET) and high linear energy transfer (high-LET) radiations have distinct effects on cells. High-LET radiation, such as alpha particles, induces clustered DNA double-strand breaks (DSBs), potentially inducing cell death more effectively. However, due to limited range, alpha-particle therapies have been restricted. In human cancer, mutations in TP53 (encoding for the p53 tumor suppressor) are the most common genetic alteration. It was previously reported that cells carrying wild-type (WT) p53 exhibit accelerated senescence and significant rates of apoptosis in response to RT, whereas cells harboring mutant p53 (mutp53) do not. This study investigated the combination of the alpha-emitting atoms RT based on internal Radium-224 (224Ra) sources and systemic APR-246 (a p53 reactivating compound) to treat tumors with mutant p53. Cellular models of colorectal cancer (CRC) or pancreatic ductal adenocarcinoma (PDAC) harboring mutant p53, were exposed to alpha particles, and tumor xenografts with mutant p53 were treated using 224Ra source and APR-246. Effects on cell survival and tumor growth, were assessed. The spread of alpha emitters in tumors was also evaluated as well as the spatial distribution of apoptosis within the treated tumors. We show that mutant p53 cancer cells exhibit radio-sensitivity to alpha particles in vitro and to alpha-particles-based RT in vivo. APR-246 treatment enhanced sensitivity to alpha radiation, leading to reduced tumor growth and increased rates of tumor eradication. Combining alpha-particles-based RT with p53 restoration via APR-246 triggered cell death, resulting in improved therapeutic outcomes. Further preclinical and clinical studies are needed to provide a promising approach for improving treatment outcomes in patients with mutant p53 tumors.