Search Results (1,050)

Chemotherapeutic agents and radiotherapy are highly effective in treating malignancies. However, they carry a significant risk of harming the gonads and may lead to endocrine dysfunction and reproductive issues. This review outlines the molecular mechanisms of gonadotoxic therapies, focusing on radiation, alkylating agents, and platinum compounds. It discusses the loss of PMFs due to gonadotoxic exposure, including DNA double-strand breaks, oxidative stress, and dysregulated signaling pathways like PI3K/PTEN/Akt/mTOR and TAp63-mediated apoptosis. Furthermore, it explores strategies to mitigate gonadal damage, including GnRH agonists, AMH, imatinib, melatonin, sphingolipid metabolites, G-CSF, mTOR inhibitors, AS101, and LH. These therapies, paired with existing fertility preservation methods, could safeguard reproductive and hormonal functions and improve the quality of life for young cancer patients. Despite the progress made in recent years in understanding gonadotoxic mechanisms, gaps remain due to questionable reliance on mouse models and the lack of models replicating human ovarian dynamics. Long-term studies are vital for wider analyses and exploration of protective strategies based on various animal models and clinical trials. It is essential to verify that these substances do not hinder the anti-cancer effectiveness of treatments or cause lasting DNA changes in granulosa cells, raising the risk of miscarriages and infertility. Full article

Replication timing (RT), the temporal order of DNA replication during S phase, influences regional mutation rates, yet the mechanistic basis for RT-associated mutagenesis remains incompletely defined. To identify drivers of RT-dependent mutation biases, we analyzed whole-genome sequencing data from cells with disruptions in DNA replication/repair genes or exposed to mutagenic compounds. Mutation distributions between early- and late-replicating regions were compared using bootstrapping and statistical modeling. We identified 14 genes that exhibit differential effects in early- or late-replicating regions, encompassing multiple DNA repair pathways, including mismatch repair (MLH1, MSH2, MSH6, PMS1, and PMS2), trans-lesion DNA synthesis (REV1) and double-strand break repair (DCLRE1A and PRKDC), DNA polymerases (POLB, POLE3, and POLE4), and other genes central to genomic instability (PARP1 and TP53). Similar analyses of mutagenic compounds revealed 19 compounds with differential effects on replication timing. These results establish replication timing as a critical modulator of mutagenesis, with distinct DNA repair pathways and exogenous agents exhibiting replication timing-specific effects on genomic instability. Our systematic bioinformatics approach identifies new DNA repair genes and mutagens that exhibit differential activity during the S phase. These findings pave the way for further investigation of factors that contribute to genome instability during cancer transformation. Full article

Background: Often, neoadjuvant therapy, which relies on the induction of double-strand breaks (DSBs), is used prior to surgery to shrink tumors by inducing cancer cell apoptosis. However, recent studies have suggested that this treatment may also induce a fluctuating state between senescence and stemness in PA-1 embryonal carcinoma cells, potentially affecting therapeutic outcomes. Thus, the respective epigenetic pathways are up or downregulated over a time period of days. These fluctuations go hand in hand with changes in spatial DNA organization. Methods: By means of Single-Molecule Localization Microscopy in combination with mathematical evaluation tools for pointillist data sets, we investigated the organization of euchromatin and heterochromatin at the nanoscale on the third and fifth day after etoposide treatment. Results: Using fluorescently labeled antibodies against H3K9me3 (heterochromatin tri-methylation sites) and H3K4me3 (euchromatin tri-methylation sites), we found that the induction of DSBs led to the de-condensation of heterochromatin and compaction of euchromatin, with a peak effect on day 3 after the treatment. On day 3, we also observed the co-localization of euchromatin and heterochromatin, which have marks that usually occur in exclusive low-overlapping network-like compartments. The evaluation of the SMLM data using topological tools (persistent homology and persistent imaging) and principal component analysis, as well as the confocal microscopy analysis of H3K9me3- and H3K4me3-stained PA-1 cells, supported the findings that distinct shifts in euchromatin and heterochromatin organization took place in a subpopulation of these cells during the days after the treatment. Furthermore, by means of flow cytometry, it was shown that the rearrangements in chromatin organization coincided with the simultaneous upregulation of the stemness promotors OCT4A and SOX2 and senescence promotors p21Cip1 and p27. Conclusions: Our findings suggest potential applications to improve cancer therapy by inhibiting chromatin remodeling and preventing therapy-induced senescence. Full article

Nanoceria is a multifaceted enzyme-like catalyst of ROS-mediated (reactive oxygen species) reactions, which results in its multiple biomedical applications. Biodegradable polysaccharide coatings improve biocompatibility, while the effects of these coatings on the ROS-related activity of nanoceria in cells need thorough studies. Here, we used human embryonic lung fibroblasts to study the effects of maltodextrin and chitosan coatings on cellular oxidative metabolism of nanoceria by examining cell viability, mitochondrial potential, accumulation of nanoparticles in cells, intracellular ROS, expression of NOX4 (NADPH oxidase 4), NRF2 (nuclear factor erythroid 2-related factor 2), NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), and STAT3 (signal transducer and activator of transcription 3) proteins as well as the expression of biomarkers of DNA damage/repair, cell proliferation, and autophagy. Both types of polysaccharide-coated nanoceria were non-toxic up to millimolar concentrations. For maltodextrin-coated nano-CeO₂, in contrast to bare nanoparticles, there was no oxidative DNA damage/repair with moderate activation of NOX4 expression. Like bare nanoceria, maltodextrin-coated nanoparticles demonstrate the proliferative impact and do not activate autophagy. However, maltodextrin-coated nanoparticles have an activating impact on mitochondrial potential and the NF-κB pathway. Chitosan-coated nanoceria causes short-term intracellular oxidative stress, activation of the expression of NOX4, STAT3, and NRF2, oxidative DNA damage, and double-strand breaks accompanied by activation of DNA repair systems. In contrast to maltodextrin-coated nanoparticles, chitosan-coated nanoceria inhibits the NF-κB pathway and activates autophagy. These findings would be useful in the development of advanced nanoceria-based pharmaceuticals and contribute to the understanding of the biochemical properties of nanoceria as a modulator of ROS-dependent signaling pathways. Full article

Modified oligonucleotides (oligos) are widely used as convenient tools in many scientific fields, including biomedical applications and therapies. In particular, oligos with lipophilic groups attached to the backbone ensure penetration of the cell membrane without the need for transfection. This study examines the interaction between amphiphilic DNA duplexes, in which one of the chains contains a lipophilic substituent, and several DNA repair proteins, particularly DNA-damage-dependent PARPs, using various biochemical approaches. DNA with a lipophilic substituent (LS-DNA) demonstrates more efficient binding with DNA damage activated poly(AD-ribose) polymerases 1-3 (PARP1, PARP2, PARP3) and DNA polymerase β. Chemically reactive LS-DNA derivatives containing a photoactivatable nucleotide (photo-LS-DNAs) or a 5′ deoxyribose phosphate (dRP) group in the vicinity of double-strand breaks (DSBs) are used for the affinity labelling of PARPs and other proteins in several whole-cell extracts of human cells. In particular, photo-LS-DNAs are used to track the level of Ku antigen in the extracts of neuron-like differentiated SH-SY5Y, undifferentiated SH-SY5Y, and olfactory epithelial cells. In vitro, PARP1–PARP3 are shown to be able to slowly excise the 5′ dRP group at DSBs. LS-DNAs can activate PARP1 and PARP2 for autoPARylation, albeit less effectively than regular DNA duplexes. Full article

Background/Objectives: Radiotherapy (RT) is a mainstay of clinical cancer therapy that causes broad immune responses. The complement system is a pivotal effector mechanism in the innate immune response, but the impact of RT is less well understood. This study investigates the interaction between RT and the complement system as a possible approach to improve immune responses in cancer treatment. Methods: Human solid cancer (lung, prostate, liver, breast cancer), lymphoma, and leukemia cells were irradiated using X-rays and treated with polyclonal antibodies or anti-CD20 monoclonal antibodies, respectively. Chromium release assay was applied to measure cell lysis after radiation with or without complement-activating antibody treatment. The expression of membrane-bound complement regulatory proteins (mCRPs; CD46, CD55, CD59), which confer resistance against complement activation, CD20 expression, apoptosis, and radiation-induced DNA double-strand breaks (γH2AX), was measured by flow cytometry. The radiosensitivity of tumor cells was assessed by colony-forming assay. Results: We demonstrate that RT profoundly impacts complement function by upregulating the expression of membrane-bound complement regulatory proteins (mCRPs) on tumor cells in a dose- and time-dependent manner. Impaired complement-mediated tumor cell lysis could thus potentially contribute to radiotherapeutic resistance. We also observed RT-induced upregulation of CD20 expression on lymphoma and leukemic cells. Notably, complement activation prior to RT proved more effective in inducing RT-dependent early apoptosis compared to post-irradiation treatment. While complement modulation does not significantly alter RT-induced DNA-damage repair mechanisms or intrinsic radiosensitivity in cancer cells, our results suggest that combining RT with complement-based anti-cancer therapy may enhance complement-dependent cytotoxicity (CDC) and apoptosis in tumor cells. Conclusions: This study sheds light on the complex interplay between RT and the complement system, offering insights into potential novel combinatorial therapeutic strategies and a potential sequential structure for certain tumor types. Full article

The incidence of sperm DNA fragmentation (SDF) in the ejaculate has garnered increasing attention in recent years due to its negative impact on reproductive outcomes. SDF involves two primary types of damage to the canonical double helix of DNA: single-strand breaks and double-strand breaks. Both of these can occur throughout the entire process of gametogenesis. Determining the precise causes of elevated SDF remains challenging, as it is influenced by a wide range of physiological processes and environmental factors. This review comprehensively explores the mechanisms underlying SDF, with a particular emphasis on the critical role of deoxyribonucleases (DNases) across different stages of male gamete development, as well as their relevance in assisted reproductive technologies (ART). Full article

Objectives: Beta-emitting radionuclide therapy, exemplified by ¹⁷⁷Lu-Oxodotreotide (Lutathera^®), enables targeted treatment of neuroendocrine tumors by delivering β-radiation to tumor cells. However, the dose-dependent molecular mechanisms underlying cellular damage remain insufficiently characterized. This study aimed to investigate the phenotypic changes in IMR-32 human neuroblastoma cells following Lutathera exposure, with a focus on the dose-dependent relationship between radiation and cellular damage. Methods: IMR-32 cells were allocated to control, low- (0.05 MBq/mL), medium- (0.5 MBq/mL), and high-dose (5 MBq/mL) groups and treated with ¹⁷⁷Lu-Oxodotreotide for 24 h. Flow cytometry was employed to assess cell viability, apoptosis, mitochondrial membrane potential, γ-H2AX expression (a marker of DNA damage), and proliferation. Results: Lutathera induced dose-dependent cytotoxic effects. Cell viability declined linearly with increasing dose (control: 100% vs. high-dose: 13.48%; r = −0.955, p < 0.001). Apoptosis was significantly elevated (control: 35.34% vs. high-dose: 88.12%; r = 0.999), accompanied by increased γ-H2AX levels (control: 5.26 × 10⁴ vs. high-dose: 13.13 × 10⁴; r = 0.930), indicating DNA double-strand breaks. Mitochondrial membrane potential decreased (control: 6.06 × 10⁴ vs. high-dose: 46.27 × 10⁴; r = 0.999), and proliferation was suppressed (control: 91.10 × 10⁴ vs. high-dose: 103.84 × 10⁴; r = 0.954), both showing strong dose correlations (p < 0.001). Conclusions: ¹⁷⁷Lu-Oxodotreotide exerts dose-dependent cytotoxicity in IMR-32 cells via DNA damage, mitochondrial dysfunction, and apoptosis induction. These findings underscore the necessity of optimizing dosing regimens to balance therapeutic efficacy and safety in clinical settings, providing a foundation for personalized β-emitter therapies. Full article

Stereotactic body radiotherapy (SBRT) delivers ablative radiation doses with sub-millimeter precision. Radiogenomic studies, meanwhile, provide insights into how tumor-intrinsic genetic factors influence responses to such high-dose treatments. This review explores the radiobiological mechanisms underpinning SBRT efficacy, emphasizing the roles of DNA damage response (DDR) pathways, tumor suppressor gene alterations, and inflammatory signaling in shaping tumor radiosensitivity or resistance. SBRT induces complex DNA double-strand breaks (DSBs) that robustly activate DDR signaling cascades, particularly via the ATM and ATR kinases. Tumors with proficient DNA repair capabilities often resist SBRT, whereas deficiencies in key repair genes can render them more susceptible to radiation-induced cytotoxicity. Mutations in tumor suppressor genes may impair p53-dependent apoptosis and disrupt cell cycle checkpoints, allowing malignant cells to evade radiation-induced cell death. Furthermore, SBRT provokes the release of pro-inflammatory cytokines and activates innate immune pathways, potentially leading to immunogenic cell death and reshaping the tumor microenvironment. Radiogenomic profiling has identified genomic alterations and molecular signatures associated with differential responses to SBRT and immune activation. These insights open avenues for precision radiotherapy approaches, including the use of genomic biomarkers for patient selection, the integration of SBRT with DDR inhibitors or immunotherapies, and the customization of treatment plans based on individual tumor genotypes and immune landscapes. Ultimately, these strategies aim to enhance SBRT efficacy and improve clinical outcomes through biologically tailored treatment. This review provides a comprehensive summary of current knowledge on the genetic determinants of response to stereotactic radiotherapy and discusses their implications for personalized cancer treatment. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder marked by the degeneration of dopaminergic neurons in the substantia nigra, leading to decreased dopamine levels in the striatum and causing a range of motor and non-motor impairments. Although the molecular mechanisms driving PD progression remain incompletely understood, emerging evidence suggests that the buildup of nuclear DNA damage, especially DNA double-strand breaks (DDSBs), plays a key role in contributing neurodegeneration, promoting senescence and neuroinflammation. Despite the pathogenic role for DDSB in neurodegenerative disease, targeting DNA repair mechanisms in PD is largely unexplored as a therapeutic approach. Ataxia telangiectasia mutated (ATM), a key kinase in the DNA damage response (DDR), plays a crucial role in neurodegeneration. In this study, we evaluated the therapeutic potential of AZD1390, a highly selective and brain-penetrant ATM inhibitor, in reducing neuroinflammation and improving behavioral outcomes in a mouse model of α-synucleinopathy. Four-month-old C57BL/6J mice were unilaterally injected with either an empty AAV1/2 vector (control) or AAV1/2 expressing human A53T α-synuclein to the substantia nigra, followed by daily AZD1390 treatment for six weeks. In AZD1390-treated α-synuclein mice, we observed a significant reduction in the protein level of γ-H2AX, a DDSB marker, along with downregulation of senescence-associated markers, such as p53, Cdkn1a, and NF-κB, suggesting improved genomic integrity and attenuation of cellular senescence, indicating enhanced genomic stability and reduced cellular aging. AZD1390 also significantly dampened neuroinflammatory responses, evidenced by decreased expression of key pro-inflammatory cytokines and chemokines. Interestingly, mice treated with AZD1390 showed significant improvements in behavioral asymmetry and motor deficits, indicating functional recovery. Overall, these results suggest that targeting the DDR via ATM inhibition reduces genotoxic stress, suppresses neuroinflammation, and improves behavioral outcomes in a mouse model of α-synucleinopathy. These findings underscore the therapeutic potential of DDR modulation in PD and related synucleinopathy. Full article

Purpose: The development of acquired resistance to arginine deprivation therapy (ADT) is a major barrier to its efficacy. This study aimed to elucidate the possible mechanisms underlying the resistance to ADT. Methods: We applied repeated ADT and established a subline SAS-R9 of the human head and neck squamous cell carcinoma (HNSCC) cells semi-resistant to arginine (Arg) deprivation in vitro. This subline was compared to the parental SAS cell lines for its relative clonogenic proliferation, aggregation, adhesion, and migration capacities. The transcriptomic changes were assessed by RNA sequencing. Signaling pathway alterations were confirmed by RT-PCR and Western blotting. Relative cell radioresistance was analyzed by radiobiological clonogenic survival assay. DNA double-strand break (DSB) repair was assessed by γH2A.X foci analysis. Results: SAS-R9 cells showed higher survival in response to ADT and radiotherapy, elevated clonogenic proliferation rate, cell–cell aggregation, and cell–matrix adhesion, along with increased epithelial–mesenchymal transition (EMT) markers and enhanced DNA DSB repair, potentially related to a more aggressive and therapy-resistant phenotype. Conclusions: While acute ADT has radiosensitizing potential, this new study suggests that long-term, repeated ADT is associated with cell selection and reprogramming, resulting in resistance to radiotherapy-induced DNA damage and higher tumor cell aggressiveness. Full article

In this study, the chemopreventive effects of rosmarinic acid (RA), a major phenolic acid of the plant Rosmarinus officinalis L., against the carcinogenic naturally occurring mycotoxin aflatoxin B1 (AFB1) were investigated using both in silico and in vitro approaches. The in silico investigation of the chemical reactions between rosmarinic acid and the carcinogenic metabolite of AFB1, aflatoxin B1 exo-8,9-epoxide (AFBO), was conducted by activation free energies calculations with DFT functionals M11-L and MN12-L, in conjunction with the 6-311++G(d,p) flexible basis set and implicit solvation model density (SMD), according to a newly developed quantum mechanics-based protocol for the evaluation of carcinogen scavenging activity (QM-CSA). Following the computational analyses, the chemoprotective effects of RA were further studied in vitro in human hepatocellular carcinoma HepG2 cells by analyzing its influence on AFB1-induced genotoxicity using a comet assay, γH2AX, and p-H3, while its impact on cell proliferation and cell cycle modulation was assessed using flow cytometry. Our computational results revealed that the activation free energy required for the reaction of RA with AFBO (14.86 kcal/mol) is significantly lower than the activation free energy for the competing reaction of AFBO with guanine (16.88 kcal/mol), which indicates that RA acts as an efficient natural scavenger of AFBO, potentially preventing AFB1-specific DNA adduct formation. The chemoprotective activity of RA was confirmed through in vitro experiments, which demonstrated a statistically significant (p < 0.05) reduction in AFB1-induced single- and double-strand breaks in HepG2 cells exposed to a mixture of AFB1 and RA at non-cytotoxic concentrations. In addition, RA reversed the AFB1-induced reduction in cell proliferation. Full article

A myriad of biological effects can be stimulated by ultrasound (US) for the treatment of cancer. The objective of our research was to investigate the effect of ultrasound alone and in combination with chemotherapeutic drugs such as doxorubicin (DOX) and temozolomide (TMZ) on human glioblastoma (GBM) and the human epidermoid carcinoma cancer 2D and 3D cell cultures. The results indicated that the US 96-probe device could induce tumour sphere cytotoxicity in a dosage- and time-dependent manner, with multiple treatments augmenting this cytotoxic effect. With enhanced cytotoxicity, US decreased tumour sphere growth metabolic activity, disrupted spheroid integrity, and heightened the occurrence of DNA double strand breaks, resulting in damage to tumour spheres and an inability to rebuild tumour spheres after multiple US treatments. The combination of US and TMZ/DOX enhanced the efficiency of treatment for GBM and epidermoid carcinoma by enhancing induced cytotoxicity in 3D tumour spheres compared to 2D monolayer cells and also by increasing the incubation time, which is the most crucial way to differentiate between the effectiveness of drug treatment with and without US. In conclusion, our data demonstrate that US enhances drug diffusion, uptake, and cytotoxicity using 3D spheroid models when compared with 2D cultures. They also demonstrate the significance of 3D cell culture models in drug delivery and discovery research. Full article

The genome is continuously exposed to different harmful factors whose activity causes different types of lesions. On the other hand, during the DNA replication process, a ribonucleoside (rN) can be inserted more frequently than the occurrence of DNA damage in the genome. Notably, it can be expected that their presence and chemical lability change the electronic properties of the double helix. In this study, a short ds-oligo with a single rN was taken into consideration. The ground-state molecular geometry was obtained at the M06-2x/D95* level of theory in the aqueous phase, while the energy and vertical and adiabatic electron affinity and ionisation potential were obtained at M06-2x/6-31++G**. The obtained results indicate that the 3′,5′-phosphodiester bond cleavage is favourable after the adiabatic cation and anion states are achieved by ds-DNA. Moreover, the lowest ionisation potential and highest electron affinity of 2.76 and 5.55 eV, respectively, which make it a suitable endpoint for electrons and holes, have been found for the final product that contains a single-strand break. Additionally, after the internucleotide 3′,5′→2′,5′ bond migration process, proton-coupled electron transfer was found to occur. In this article, the electronic properties of short ds-DNA fragments with ribonucleoside inserts are reported for the first time. The obtained results suggest that rNs can play a significant role in the communication of repair and replication proteins via electron transfer, especially after rearrangement. Moreover, the discussed internucleotide bond stability changes after one-electron oxidation or reduction and can support new radiotherapy strategies that are safer and more effective. Further theoretical and experimental studies are highly warranted. Full article

HSP110 is a ubiquitous chaperone contributing to proteostasis. It has a disaggregation activity and can refold denatured proteins. It can regulate fundamental signaling pathways involved in oncogenesis, such as Wnt/β-catenin, NF-κB and STAT3 signaling pathways. In gastric and colorectal cancer, HSP110 has been detected in the nucleus, and nuclear expression has been associated with the resistance of cells to 5-FU chemotherapy. Nuclear translocation of HSP110 is promoted by the exposure of cells to DNA-damaging agents. In a previous work, we demonstrated that nuclear HSP110 participates in the NHEJ DNA repair pathway by facilitating the recruitment of DNA-PKcs to Ku70/80 heterodimers at the site of DNA double-strand breaks. In the present work, analysis of HSP110s’ nuclear interactome revealed an enrichment of components from SWI/SNF chromatin remodeling complexes. We demonstrate that HSP110 is strongly associated with chromatin in temozolomide- and oxaliplatin-treated cells and directly interacts with the core subunit SMARCC2, thereby facilitating the assembly of SWI/SNF complexes. This work expands upon the role of HSP110, which regulates not only proteostasis but also the assembly of critical nuclear macromolecular complexes involved in the adaptive stress response. Full article