Search Results (856)

The ataxia–telangiectasia-mutated (ATM) protein plays a crucial role in the DNA damage response, particularly in the homologous recombination (HR) pathway. This study aimed to assess the impact of deleterious ATM variants on homologous recombination deficiency (HRD) and response to PARP inhibitors (PARPi) in melanoma patients, using a cell line established from melanoma tissue of a patient carrying the c.5979_5983del germline ATM variant. Despite proven loss of heterozygosity, lack of ATM activation, and HRD, our model did not show sensitivity to PARPi. We assessed the potential contribution of the Schlafen family member 11 (SLFN11) helicase, whose expression is inversely correlated with PARPi sensitivity in other cancers, to the observed resistance. The ATM mutant cell line lacked SLFN11 expression and featured hypermethylation-mediated silencing of the SLFN11 promoter. While sensitive to the ATR inhibitor (ATRi), the addition of ATRi to PARPi was unable to overcome the resistance. Our findings suggest that ATM mutational status and HRD alone do not adequately account for variations in sensitivity to PARPi in our model. A comprehensive approach is essential for optimizing the exploitation of DNA repair defects and ultimately improving clinical outcomes for melanoma patients. Full article

Cadmium (CAD) is a prevalent environmental contaminant that poses serious cardiotoxic risks. The heart, kidney, liver, and brain are just a few of the essential organs that can sustain serious harm from CAD, a very poisonous heavy metal. The cardiotoxic mechanism of CAD is linked to oxidative damage and inflammation. A trace element with anti-inflammatory, anti-apoptotic, and antioxidant qualities, selenium (SEL) can be taken as a dietary supplement. The biotoxicity of heavy metal CAD is significantly inhibited by SEL, a mineral that is vital to human and animal nutrition. Through ROS-induced PARP-1/ADPR/TRPM2 pathways, this study seeks to assess the preventive benefits of selenium against cardiovascular damage caused by CAD. The SEL showed encouraging results in reducing inflammatory and oxidative reactions. Rats were given 0.5 mg/kg SEL and 3 mg/kg 2-Aminoethyl diphenylborinate (2-APB) intraperitoneally for five days, in addition to 25 mg/kg CAD given via gavage. Histopathological examination findings revealed that the morphologic changes in the hearts of the CAD group rats were characterised by marked necrosis and the degeneration of myocytes and congestion of vessels. Compared to the rats in the CAD group, the hearts of the SEL, 2-APB and SEL+2-APB groups showed fewer morphological alterations. Moreover, in rats given CAD, there was an increase in cardiac malondialdehyde (MDA), total oxidant (TOS), reactive oxygen species (ROS), caspase (Casp-3-9), and TNF-α, whereas glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and total antioxidant (TAS) decreased. SEL improved antioxidants, avoided tissue damage, and reduced cardiac MDA, TOS, and ROS. In rats given CAD, SEL decreased cardiac PARP-1, TRPM2, TNF-α, and caspase. In summary, by reducing oxidative stress and cardiac damage and modifying the ROS/PARP-1/TRPM2 pathway, SEL protected against CAD cardiotoxicity. Full article

Advanced renal cell carcinoma (RCC) has a poor prognosis; this drives the exploration of alternative systemic therapies to identify more effective treatment options. Recent research has revealed that crebanine, an alkaloid derivative of the Stephania genus, induces apoptotic effects in various cancers; however, a thorough investigation of the role of crebanine in RCC has not been conducted thus far. For this study, we evaluated tumor cell viability, clonogenicity, cell-cycle distributions, morphological changes, and cell mortality with the aim of exploring the antitumor effects of crebanine in RCC. Furthermore, we compared gene and protein expressions using RNA sequencing analysis and Western blotting. The findings indicated that crebanine significantly inhibited RCC colonies and caused G1-phase cell-cycle arrest with sub-G1-phase accumulation, thus leading to suppressed cell proliferation and cell death. In addition, Hoechst 33342 staining was used to observe apoptotic cells, which revealed chromatin condensation and a reduction in the nuclear volume associated with apoptosis. Further, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that differentially expressed genes are involved in the initiation of DNA replication, centrosome duplication, chromosome congression, and mitotic processes in the cell cycle along with signaling pathways, such as I-kappaB kinase/NF-kappaB signaling, Hippo signaling, and intrinsic apoptotic pathways. Consistent with GO and KEGG analyses, increased levels of cleaved caspase-3, cleaved caspase-7, and cleaved PARP, and decreased levels of cIAP1, BCL2, survivin, and claspin were observed. Finally, the expressions of G1/S phase transition cyclin D1, cyclin E/CDK2, and cyclin A2/CDK2 complexes were downregulated. Overall, these findings supported the potential of crebanine as an adjuvant therapy in RCC. Full article

Triple-negative breast cancer (TNBC) is a highly aggressive subtype known for its rapid metastatic potential. Despite its severity, treatment options for TNBC remain limited. Olaparib, an FDA-approved PARP inhibitor, has been used to treat germline BRCA-mutated TNBC in both metastatic and high-risk early-stage settings. However, acquired resistance to PARP inhibitors and their limited applicability in non-BRCA TNBCs are now two major growing clinical problems. Activation of the IL-6/STAT3 signaling cascade has been implicated in therapeutic resistance. In this study, we evaluated the combined effects of the PARP inhibitor olaparib and the STAT3 inhibitor LLL12B in human TNBC cell lines with both BRCA mutations and wild-type BRCA status. Our results demonstrate that the PARP inhibitor olaparib can induce increased interleukin-6 (IL-6) in TNBC cells, with ELISA showing a 2- to 39-fold increase across five cell lines. MTT assays revealed that knocking down or inhibiting STAT3, a key downstream effector of the IL-6/GP130 pathway, sensitizes TNBC cells to olaparib. Treatment with either olaparib or LLL12B alone reduced TNBC cell viability, migration, and invasion. Notably, their combined administration produced a markedly enhanced inhibitory effect compared to individual treatments, regardless of BRCA mutation status. These findings highlight the potential of dual PARP and STAT3 inhibition as a novel targeted therapeutic strategy for both BRCA-mutant and BRCA-proficient TNBC. Full article

Ultraviolet A (UVA) radiation has been identified as a significant factor contributing to skin photoaging and skin diseases, operating through the excessive generation of reactive oxygen species (ROS) and the subsequent induction of DNA damage. Plant-derived antioxidants have demonstrated efficacy in mitigating UVA-induced damage; nevertheless, their instability limits their therapeutic potential. This study investigates the mechanisms of antioxidant and cytoprotective effects of squalane (Sq), a stable, plant-derived triterpene, in human dermal fibroblasts (HDFs) exposed to UVA radiation. Sq was administered at concentrations ranging from 0.005% to 0.015% prior to UVA exposure (10 J/cm²). It has been found that Sq counteracted UVA-induced ROS formation, decreased the level of reduced thiol groups, activated apoptosis, and inhibited DNA biosynthesis. Immunofluorescence analysis revealed that Sq suppressed the UVA-induced expression of p53, caspase-3, caspase-9, and PARP, while restoring the activity of the pro-survival p-Akt/mTOR pathway. The findings indicate that Sq exerts protective effects on UVA-induced fibroblast damage through a combination of antioxidant and anti-apoptotic mechanisms. Full article

BGP-15, a poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor exerts cardioprotective effects; however, the underlying mechanisms remain unclear. Therefore, our study aimed to investigate the effects of BGP-15 on the imatinib (Imtb)-induced cardiac inflammation at the biochemical level. Male rats were divided to control, Imtb-treated (60 mg/kg/day for 14 days), and Imtb + BGP-15-treated animals. In this group Imtb was co-administered with BGP-15 at the dose of 10 mg/kg/day. At the end of the experiment, nuclear factor-kappa B/p65 (NF-κB/p65), nuclear transcription factor erythroid-2 related factor (Nrf2), heme oxygenase-1 (HO-1), high mobility group box 1 (HMGB1), and myeloperoxidase (MPO) were measured by Western blot. Chemokine and interleukins (ILs) were determined by Legendplex. Additionally, cardiac specific changes were visualized by immunohistochemistry. We demonstrated that Imtb increased NF-κB/p65, IL-6, IL-1β, IL-18, MCP-1, HMGB1, as well as the expression and activity of MPO. Conversely, the expressions of antioxidant Nrf2 and HO-1 were decreased. Administration of BGP-15 effectively mitigated these inflammatory alterations by significantly reducing pro-inflammatory cytokines and MPO activity, while simultaneously restoring and enhancing the levels of Nrf2 and HO-1, thereby promoting antioxidant defenses. The immunohistochemical staining further supported these biochemical changes. Our study provides new and comprehensive biochemical insight for managing Imtb-induced inflammatory responses via BGP-15-induced PARP1 inhibition. Full article

Poly(ADP-ribosyl)ation is a crucial posttranslational modification that governs gene expression, chromatin remodeling, and cellular homeostasis. This dynamic process is mediated by the opposing activities of poly(ADP-ribose) polymerases (PARPs), which synthesize poly(ADP-ribose) (pADPr), and poly(ADP-ribose) glycohydrolase (PARG), which degrades it. While PARP function has been extensively studied, the structural and mechanistic basis of PARG-mediated pADPr degradation remain incompletely understood. To investigate the role of PARG in pADPr metabolism, we employed CRISPR/Cas9-based genome editing to generate a novel Parg^29b mutant mouse embryonic stem cell (ESC) line carrying a precise deletion within the PARG catalytic domain. This deletion completely abolished pADPr hydrolytic activity, resulting in massive nuclear pADPr accumulation, yet ESC viability, proliferation, and cell cycle progression remained unaffected. Using Drosophila melanogaster as a model system, we demonstrated that this mutation completely disrupted the pADPr pathway and halted developmental progression, highlighting the essential role of PARG and pADPr turnover in organismal development. Our results define a critical structural determinant of PARG catalytic function, underscore the distinct requirements for pADPr metabolism in cellular versus developmental contexts, and provide a genetically tractable model for studying the regulation of poly(ADP-ribose) dynamics and therapeutic responses to PARP inhibition in vivo. Full article

Urolithin A, which is a natural gut microbial metabolite, exerts multiple beneficial effects upon supplementation, including prolonging lifespan, mitigating diseases, restoring the quality of aged oocytes and alleviating drug toxicity. The study aims to investigate the ovarian protective role of Urolithin A using a neonatal mouse ovarian in vitro culture and chemotherapy model, with a particular focus on its mechanisms for inhibiting primordial follicle activation and mitigating cyclophosphamide (CY) or 4-hydroperoxy (4-HC)-induced follicle apoptosis. The results showed that Urolithin A significantly decreased the number of growing follicles and downregulated the expression of oocyte growth-related genes (Gdf9 and Zp3) and protein (DDX4), as well as Ki-67 and BrdU-positive signals. Further studies revealed that Urolithin A significantly downregulated the levels of phosphorylated Akt and FOXO3a and decreased the percentage of oocytes with FOXO3a nuclear export. Molecular docking showed a strong binding ability between Urolithin A and its downregulated gene Pik3cg. Moreover, Urolithin A significantly decreased CY- and 4-HC-induced increases in cleaved Caspase-3- and PARP1-positive signals. Meanwhile, RNA-seq analysis indicated that Urolithin A significantly downregulated CY-induced expression of DNA damage-related genes (Trp73 and Trim29). In short, Urolithin A inhibits primordial follicle activation by reducing PI3K/Akt signaling reactivity. Furthermore, Urolithin A prevents CY-induced follicle apoptosis. The study provides valuable insights into Urolithin A treatment for chemotherapy-induced infertility. Full article

Fatty acid synthase (FASN) is frequently overexpressed in human breast cancer and has emerged as a potential therapeutic target. Resveratrol has been shown to inhibit FASN activity in vitro through both fast-reversible and slow-irreversible mechanisms. In this study, resveratrol reduced intracellular fatty acid levels by inhibiting FASN activity and downregulating its expression across various breast cancer subtypes, including SK-BR-3, MCF-7, and MDA-MB-231 cells. Knockdown of FASN via small interfering RNA (siRNA) further enhanced resveratrol-induced cytotoxicity. Resveratrol significantly suppressed cell viability and triggered apoptosis, as evidenced by increased cleavage of poly(ADP-ribose) polymerase (PARP) and disruption of Bcl-2 family protein balance. Furthermore, resveratrol inhibited key signaling pathways involved in cell proliferation and survival, notably FAK, AKT, and ERK1/2. FASN silencing by siRNA also modulated the activation states of these signaling proteins. Collectively, these findings support resveratrol as a promising anti-cancer candidate that induces apoptosis in diverse breast cancer subtypes via FASN inhibition. Full article

Janus kinase 2 (JAK2) inhibitors have gained regulatory approval for treating various human diseases. While the JAK2/signal tranducer and activator of transcription 3 (STAT3) pathway plays a role in tumorigenesis, JAK2/STAT3 inhibitors have shown limited therapeutic efficacy in triple-negative breast cancer (TNBC). In this study, we assessed the antiproliferative effects of clinically approved JAK2 inhibitors in TNBC cell lines (MDA-MB-231 and HS578T) using the MTT assay. Among the four JAK2 inhibitors evaluated (fedratinib, cerdulatinib, peficitinib, and filgotinib), fedratinib significantly inhibited the proliferation of TNBC cells with IC₅₀ values below 2 μM. Fedratinib also demonstrated superior efficacy in inhibiting long-term colony formation compared to other JAK2 inhibitors. Western blot analyses showed that fedratinib uniquely inhibits the phosphoinositide 3-kinase (PI3K)/AKT pathway and moderately affects the MAP kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, in addition to targeting JAK2/STAT3 signaling. Moreover, fedratinib distinctly decreased MYC and cyclin D1 protein levels while inducing poly (ADP-ribose) polymerase (PARP) cleavage and apoptotic cell death more effectively than other JAK2 inhibitors. We next investigated the effects of simultaneously inhibiting JAK2/STAT3 together with the MEK/ERK or PI3K/AKT pathways, as well as the impact of triple pathway inhibition. Notably, combining ceduratinib with either cobimetinib (MEK inhibitor) and ipatasertib (AKT inhibitor) or trametinib (MEK inhibitor) and alpelisib (PI3K inhibitor) mimicked the effects of fedratinib on the cell proliferation, MYC and cyclin D1 suppression, and pro-apoptotic protein induction. These finding suggest that JAK2 inhibition enhances the anticancer effects of concurrent MEK/ERK and PI3K/AKT pathway inhibition, while JAK2 inhibition alone shows minimal efficacy in TNBC cells. Full article

Poly(ADP-ribose) polymerases (PARP) are a family of enzymes that were proven to play an essential role in the initiation and activation of DNA repair processes in the case of DNA single-strand breaks. The inhibition of PARP enzymes might be a promising option for the treatment of several challenging types of cancers, including triple-negative breast cancer (TNBC) and non-small cell lung carcinoma (NSCLC). This study utilizes several techniques to screen the compound collection of the Leibniz Institute of Plant Biochemistry (IPB) to identify novel hPARP-1 inhibitors. First, an in silico pharmacophore-based docking study was conducted to virtually screen compounds with potential inhibitory effects. To evaluate these compounds in vitro, a cell-free enzyme assay was developed, optimized, and employed to identify hPARP-1 inhibitors, resulting in the discovery of two novel scaffolds represented by compounds 54 and 57, with the latter being the most active one from the compound library. Furthermore, fluorescence microscopy and synergism assays were performed to investigate the cellular and nuclear pathways of hPARP-1 inhibitor 57 and its potential synergistic effect with the DNA-damaging agent temozolomide. The findings suggest that the compound requires further lead optimization to enhance its ability to target the nuclear PARP enzyme effectively. Nonetheless, this new scaffold demonstrated a five-fold higher PARP inhibitory activity at the enzyme level compared to the core structure of olaparib (OLP), phthalazin-1(2H)-one. Full article

Background/Objectives: PARP inhibitors (PARPis) currently play frontline roles in the management of prostate, pancreatic, ovarian and breast cancers, but their roles in colorectal cancer (CRC) management have yet to be clarified. Importantly, the specific predictive biomarkers for PARPis in CRC are still matters of investigations. The aim of this study is to identify the potential predictive biomarkers of PARP inhibition in CRC. Methods: Gene set enrichment analyses (GSEAs) and drug ontology enrichment analyses (DOEAs) of PARPi response gene sets were applied as the surrogates of PARPi response to two CRC cohorts in order to compare the predictive capacities of TP53 mutation status, MSI status, as well as PARP1 and PARP2 expression for PARP inhibition to those of a homologous repair deficiency surrogate, and large-scale state transition (LST). Differential enrichment score (ES) and ontology enrichment (OE) analyses were used to interrogate the differential correlation of the predictive biomarkers with PARPi response, relative to LST. Results: The results demonstrated that LST-low, rather than LST-high, CRC subsets exhibited an enrichment of the PARPi response, in contrast to what has been established for other cancers. Furthermore, CRC subsets with wild-type TP53, positive MSI, as well as high PARP1 and PARP2 expression exhibited an enrichment of the PARPi response gene sets. Moreover, there was no differential enrichment of the PARPi response between LST and each of the MSI statuses, PARP1 expression and PARP2 expression. Furthermore, the preliminary differential enrichment observed between the LST-based and TP53 mutation status-based PARPi responses could not be validated with further testing. Conclusions: MSI status, TP53 mutation status as well as PARP1 and PARP2 expression may be substitutes for low LST as predictive biomarkers of PARPi response in CRC. Full article

Background/Objectives: Currently, there is limited knowledge on the molecular mechanisms of the “non-canonical” Hippo signaling pathway in hematopoietic tumor cells. We have shown that targeting the MST1/2 kinases, which are the key molecules in this signaling pathway, may be an effective approach to the treatment of hematologic tumors. Methods: The methods used in this study include cell growth assays, caspase assays, Western blot hybridizations, flow cytometry, and whole-transcriptome analyses. These methods allowed us to better understand the molecular pathways at play. Results: Our results showed that XMU-MP-1, an inhibitor of MST1/2 kinase, specifically reduces the viability of hematopoietic cancer cells but not breast cancer cells. It effectively inhibits the growth of the tumor B- and T-cell lines by blocking cell cycle progression, mainly during the G2/M phase, inducing apoptosis and autophagy. XMU-MP-1 treatment led to increased caspase 3/7 activity and increased levels of the cleaved PARP protein. Levels of the LC3-II protein were also shown to be increased, while the level of p62 decreased. These changes are associated with apoptosis and autophagy, respectively. RNA-seq analysis has demonstrated that XMU-MP-1 suppressed the expression of cell cycle regulators, such as E2F, and cell division cycle genes CDC6,7,20,25,45; cyclins A2,B1,B2, and cyclin-dependent kinases. At the same time, it increased the expression of genes involved in apoptosis, autophagy, and necroptosis. Conclusions: Combinations of growth assays, caspase assays, Western blotting, and RNA-seq have shown that the dramatic reduction in the number of hematopoietic tumor cells after treatment with XMU-MP-1 is due to both cytostatic and cytotoxic effects. The use of MST1/2 kinase inhibitors could be highly promising for complex therapy of hematological tumors. Full article

Background/Objectives: Inflammatory disorders contribute to the pathogenesis of numerous diseases and are known to markedly reduce quality of life. Although anti-inflammatory drugs approved by the Food and Drug Administration are available, their prolonged use is frequently associated with adverse effects. In this study, we evaluated the pharmacological properties of araliadiol, a naturally occurring polyacetylene compound, as a novel anti-inflammatory agent. Methods: An in vitro hyperinflammatory model was established by stimulating RAW 264.7 cells with lipopolysaccharide (LPS). Dexamethasone (DEX) was used as a positive control to compare anti-inflammatory efficacy. The protective effects of araliadiol against LPS-induced cytotoxicity were assessed using adenosine triphosphate content and crystal violet staining assays. The anti-inflammatory activity was further examined by quantitative reverse transcriptase–polymerase chain reaction, Western blotting, cell fractionation, immunofluorescence staining, a nitric oxide assay, and an enzyme-linked immunosorbent assay. Results: Araliadiol significantly attenuated cytotoxicity and cell death in LPS-stimulated RAW 264.7 cells. It suppressed the expression of cell death markers Cleaved caspase-3 and Cleaved PARP-1. In addition, araliadiol downregulated key pro-inflammatory mediators, including inflammasome-related genes, cytokines, chemokines, and inducible nitric oxide synthase. It also reduced the expression of Cox-2 and PGE₂, indicating potential anti-hyperalgesic effects. Moreover, araliadiol inhibited the activation of Nfκb and Stat1 signaling pathways in LPS-stimulated macrophages. Conclusions: Araliadiol demonstrated robust anti-cytotoxic, anti-inflammatory, and anti-hyperalgesic activities in LPS-induced RAW 264.7 cells, with efficacy comparable to DEX. These findings support its potential as a plant-derived therapeutic candidate for the management of inflammatory conditions. Full article

Heart failure represents the terminal stage in the development of many cardiovascular diseases, and its pathological mechanisms are closely related to disturbances in energy metabolism and mitochondrial dysfunction in cardiomyocytes. In recent years, nicotinamide adenine dinucleotide (NAD⁺), a core coenzyme involved in cellular energy metabolism and redox homeostasis, has been shown to potentially ameliorate heart failure through the regulation of mitochondrial function. This review systematically investigates four core mechanisms of mitochondrial dysfunction in heart failure: imbalance of mitochondrial dynamics, excessive accumulation of reactive oxygen species (ROS) leading to oxidative stress injury, dysfunction of mitochondrial autophagy, and disturbance of Ca²⁺ homeostasis. These abnormalities collectively exacerbate the progression of heart failure by disrupting ATP production and inducing apoptosis and myocardial fibrosis. NAD⁺ has been shown to regulate mitochondrial biosynthesis and antioxidant defences through the activation of the deacetylase family (e.g., silent information regulator 2 homolog 1 (SIRT1) and SIRT3) and to increase mitochondrial autophagy to remove damaged mitochondria, thus restoring energy metabolism and redox balance in cardiomyocytes. In addition, the inhibition of NAD⁺-degrading enzymes (e.g., poly ADP-ribose polymerase (PARP), cluster of differentiation 38 (CD38), and selective androgen receptor modulators (SARMs)) increases the tissue intracellular NAD⁺ content, and supplementation with NAD⁺ precursors (e.g., β-nicotinamide mononucleotide (NMN), nicotinamide riboside, etc.) also significantly elevates myocardial NAD⁺ levels to ameliorate heart failure. This study provides a theoretical basis for understanding the central role of NAD⁺ in mitochondrial homeostasis and for the development of targeted therapies for heart failure. Full article