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Biomedicine & Pharmacotherapy =... Apr 2024Peiminine, the primary biologically active compound from Fritillaria thunbergii Miq., has demonstrated significant pharmacological activities. Doxorubicin is one of the...
Peiminine, the primary biologically active compound from Fritillaria thunbergii Miq., has demonstrated significant pharmacological activities. Doxorubicin is one of the most potent chemotherapeutic agents for breast cancer (BC). This study was designed to investigate the efficacy and underlying mechanisms of Peiminine combined with Doxorubicin in treating BC. Our results demonstrated that the combination of Peiminine and 1 mg/kg Doxorubicin exhibited more significant suppression of tumor growth compared with the monotherapy in MDA-MB-231 xenograft nude mice model, which is comparable to the effect of 3 mg/kg Doxorubicin in vivo. Notably, the 3 mg/kg Doxorubicin monotherapy resulted in organ toxicity, specifically in the liver and heart, whereas no toxicity was observed in the combination group. In vitro, this combined treatment exhibited a synergistic reduction on the viability of BC cells. Peiminine enhanced the cell cycle arrest and DNA damage induced by Doxorubicin. Furthermore, the combination treatment effectively blocked DNA repair by inhibiting the MAPKs signaling pathways. And ZEB1 knockdown attenuated the combined effect of Peiminine and Doxorubicin on cell viability and DNA damage. In conclusion, our study found that the combination of Peiminine and Doxorubicin showed synergistic inhibitory effects on BC both in vivo and in vitro through enhancing Doxorubicin-induced DNA damage. These findings support that their combination is a novel and promising therapeutic strategy for treating BC.
Topics: Mice; Animals; Humans; Female; Breast Neoplasms; Mice, Nude; Doxorubicin; DNA Adducts; Cell Line, Tumor; Apoptosis; Zinc Finger E-box-Binding Homeobox 1; Cevanes
PubMed: 38432128
DOI: 10.1016/j.biopha.2024.116353 -
JACS Au Feb 2024Peptide-based covalent inhibitors targeted to nucleophilic protein residues have recently emerged as new modalities to target protein-protein interactions (PPIs) as they...
Peptide-based covalent inhibitors targeted to nucleophilic protein residues have recently emerged as new modalities to target protein-protein interactions (PPIs) as they may provide some benefits over more classic competitive inhibitors. Covalent inhibitors are generally targeted to cysteine, the most intrinsically reactive amino acid residue, and to lysine, which is more abundant at the surface of proteins but much less frequently to histidine. Herein, we report the structure-guided design of targeted covalent inhibitors (TCIs) able to bind covalently and selectively to the bacterial sliding clamp (SC), by reacting with a well-conserved histidine residue located on the edge of the peptide-binding pocket. SC is an essential component of the bacterial DNA replication machinery, identified as a promising target for the development of new antibacterial compounds. Thermodynamic and kinetic analyses of ligands bearing different mild electrophilic warheads confirmed the higher efficiency of the chloroacetamide compared to Michael acceptors. Two high-resolution X-ray structures of covalent inhibitor-SC adducts were obtained, revealing the canonical orientation of the ligand and details of covalent bond formation with histidine. Proteomic studies were consistent with a selective SC engagement by the chloroacetamide-based TCI. Finally, the TCI of SC was substantially more active than the parent noncovalent inhibitor in an in vitro SC-dependent DNA synthesis assay, validating the potential of the approach to design covalent inhibitors of protein-protein interactions targeted to histidine.
PubMed: 38425897
DOI: 10.1021/jacsau.3c00572 -
EJNMMI Research Mar 2024Cisplatin- based chemoradiotherapy is a crucial pillar in the treatment of HNSCC. The use of cisplatin comes with high toxicity rates as 35% of patients cannot sustain...
BACKGROUND
Cisplatin- based chemoradiotherapy is a crucial pillar in the treatment of HNSCC. The use of cisplatin comes with high toxicity rates as 35% of patients cannot sustain the planned dose while response is unpredictable. Unfortunately, there are no clinically applicable biomarkers to predict response. Based on the association of response with the number of DNA adducts and the involved molecular pathway to resolve cisplatin-induced DNA crosslinks in HNSCC, [195mPt]cisplatin (CISSPECT®) might have potential to monitor drug uptake and retention before treatment, and predict cisplatin response. The aim of this study is to investigate this concept by analyzing uptake, retention and biodistribution of [195mPt]cisplatin between known cisplatin-sensitive (VU-SCC-1131) and -resistant (VU-SCC-OE) HNSCC cell lines in vitro and xenografted in mice in vivo.
RESULTS
By a variety of experiments in vitro, including cell cycle analyses, and in vivo, the sensitivity of cell line VU-SCC-1131 and resistance of cell line VU-SCC-OE for cisplatin was demonstrated. VU-SCC-OE was able to accumulate more [195mPt]cisplatin in the DNA, and showed an increased capability to repair [195mPt]cisplatin crosslinks compared to VU-SCC-1131. Notably, DNA binding of cisplatin increased even when cisplatin was removed from the medium, likely from intracellular sources. In vivo, [195mPt]cisplatin showed a rapid biodistribution to the large organs such as the liver, with no differences between intravenous and intraperitoneal administration. Most circulating [195mPt]cisplatin was cleared by renal filtration, and accumulation in kidney and liver remained high. Uptake in xenografts was rapid (blood:tumor ratio; 1:1) and highest after 1 h, while decreasing after 6 h in line with the concentration in the blood. Remarkably, there was no significant difference in uptake or retention between xenografts of the cisplatin-sensitive and -resistant cell line.
CONCLUSION
VU-SCC-1131 with a known FA deficiency and VU-SCC-OE displayed a significant difference in sensitivity to and recovery from cisplatin treatment, due to S-phase problems in VU-SCC-1131 at low doses, in line with the genetic defect. Using Pt-195m radioactivity analysis, we demonstrated the limited capability of cisplatin crosslink repair in VU-SCC-1131. Unexpectedly, we were not able to translate these findings to a mouse model for sensitivity prediction based on the biodistribution in the tumor, most likely as other factors such as influx counterbalanced repair. These data do not support response prediction by [195mPt]cisplatin, and applications to predict the toxic side-effects of cisplatin and to tailor dosing schemes seem more feasible.
PubMed: 38424294
DOI: 10.1186/s13550-024-01082-w -
International Journal of Hygiene and... Apr 2024Several aromatic amines (AA) are classified as human carcinogens, and tobacco smoke is one of the main sources of exposure. Once in the human body, they undergo...
Several aromatic amines (AA) are classified as human carcinogens, and tobacco smoke is one of the main sources of exposure. Once in the human body, they undergo different metabolic pathways which lead to either their excretion or ultimately to the formation of DNA and protein adducts. The aim of this study was to investigate AA in 68 urine samples (aged 29-79, 47% female), including 10 smokers (S), 28 past-smokers (PS) and 30 never-smokers (NS), and to study if there was a relation between the smoking status and the amount of the AA present. GCxGC-MS was used to analyze AA in complex urine samples due to its high peak capacity and the fact that it provides two sets of retention times and structural information, which facilitates the separation and identification of the target analytes. First, a qualitative comparison of an example set of a NS, PS and S sample was carried out, in which 38, 45 and 46 AA, respectively, could be tentatively identified. Afterwards, seven AA were successfully quantified in the samples. Of these, 4-ethylaniline (4EA, p = 0.015), 2,4,6-trimethylaniline (2,4,6TMA, p = 0.030), 2-naphthylamine (2NA, p = 0.014) and the sum of 2,4- and 2,6-dimethylaniline (DMA, p = 0.017) were found in significantly different (α = 0.05) concentrations for the S, 29 ± 14, 87 ± 49, 41 ± 26, and 105 ± 57 ng/L respectively, compared to the NS, 15 ± 6, 42 ± 30, 16 ± 6, and 48 ± 28 ng/L. And 2,4,6TMA (39 ± 26, p = 0.022), 2NA (18 ± 9, p = 0.025) and DMA (53 ± 46, p = 0.030), were also found at significantly higher concentrations in samples from S when compared to PS. However, some samples had AA concentrations outside the calibration curve and could not be taken into account, especially for 2-methylaniline (2MA). Therefore, all the samples were evaluated using a quantitative screening approach, by which the intensities of 4EA (p = 0.019), 2,4,6TMA (p = 0.048), 2NA (p = 0.016), DMA (p = 0.019) and 2MA (p = 0.006) in S were found to be significantly (α = 0.05) higher than in the NS, and 2MA (p = 0.019) and 4EA (p = 0.023) in S were found to be significantly higher than in the PS. An association between the smoking status and the amount of certain AA present could therefore be found. This information could be used to study the relation between the smoking status, the amount of AA present, and smoking related diseases like bladder cancer.
Topics: Humans; Female; Male; Gas Chromatography-Mass Spectrometry; Amines; Smoking; Carcinogens; 2-Naphthylamine
PubMed: 38422601
DOI: 10.1016/j.ijheh.2024.114343 -
Biochemistry Mar 2024Urea lesions in DNA arise from thymine glycol (Tg) or 8-oxo-dG; their genotoxicity is thought to arise in part due to their potential to accommodate the insertion of all...
Urea lesions in DNA arise from thymine glycol (Tg) or 8-oxo-dG; their genotoxicity is thought to arise in part due to their potential to accommodate the insertion of all four dNTPs during error-prone replication. Replication bypass with human DNA polymerase η (hPol η) confirmed that all four dNTPs were inserted opposite urea lesions but with purines exhibiting greater incorporation efficiency. X-ray crystal structures of ternary replication bypass complexes in the presence of Mg ions with incoming dNTP analogs dAMPnPP, dCMPnPP, dGMPnPP, and dTMPnPP bound opposite urea lesions (hPol η·DNA·dNMPnPP complexes) revealed all were accommodated by hPol η. In each, the Watson-Crick face of the dNMPnPP was paired with the urea lesion, exploiting the ability of the amine and carbonyl groups of the urea to act as H-bond donors or acceptors, respectively. With incoming dAMPnPP or dGMPnPP, the distance between the imino nitrogen of urea and the N9 atoms of incoming dNMPnPP approximated the canonical distance of 9 Å in B-DNA. With incoming dCMPnPP or dTMPnPP, the corresponding distance of about 7 Å was less ideal. Improved base-stacking interactions were also observed with incoming purines vs pyrimidines. Nevertheless, in each instance, the α-phosphate of incoming dNMPnPPs was close to the 3'-hydroxyl group of the primer terminus, consistent with the catalysis of nucleotidyl transfer and the observation that all four nucleotides could be inserted opposite urea lesions. Preferential insertion of purines by hPol η may explain, in part, why the urea-directed spectrum of mutations arising from Tg vs 8-oxo-dG lesions differs.
Topics: Humans; 8-Hydroxy-2'-Deoxyguanosine; DNA-Directed DNA Polymerase; DNA Damage; DNA; DNA Replication; Nucleotides; DNA Adducts
PubMed: 38413007
DOI: 10.1021/acs.biochem.3c00569 -
BioRxiv : the Preprint Server For... Feb 2024Mitomycin C (MMC) repair factor A () and factor B (), encode a conserved helicase and exonuclease that repair DNA damage in the soil-dwelling bacterium . Here we have...
Mitomycin C (MMC) repair factor A () and factor B (), encode a conserved helicase and exonuclease that repair DNA damage in the soil-dwelling bacterium . Here we have focused on the characterization of MrfB, a DEDDh exonuclease in the DnaQ superfamily. We solved the structure of the exonuclease core of MrfB to a resolution of 2.1 Å, in what appears to be an inactive state. In this conformation, a predicted α-helix containing the catalytic DEDDh residue Asp172 adopts a random coil, which moves Asp172 away from the active site and results in the occupancy of only one of the two catalytic Mg ions. We propose that MrfB resides in this inactive state until it interacts with DNA to become activated. By comparing our structure to an AlphaFold prediction as well as other DnaQ-family structures, we located residues hypothesized to be important for exonuclease function. Using exonuclease assays we show that MrfB is a Mg-dependent 3'-5' DNA exonuclease. We show that Leu113 aids in coordinating the 3' end of the DNA substrate, and that a basic loop is important for substrate binding. This work provides insight into the function of a recently discovered bacterial exonuclease important for the repair of MMC-induced DNA adducts.
PubMed: 38405983
DOI: 10.1101/2024.02.15.580553 -
International Journal of Molecular... Feb 2024Excessive consumption of food rich in saturated fatty acids and carbohydrates can lead to metabolic disturbances and cardiovascular disease. Hyperlipidemia is a...
Excessive consumption of food rich in saturated fatty acids and carbohydrates can lead to metabolic disturbances and cardiovascular disease. Hyperlipidemia is a significant risk factor for acute cardiac events due to its association with oxidative stress. This leads to arterial wall remodeling, including an increase in the thickness of the intima media complex (IMT), and endothelial dysfunction leading to plaque formation. The decreased nitric oxide synthesis and accumulation of lipids in the wall result in a reduction in the vasodilating potential of the vessel. This study aimed to establish a clear relationship between markers of endothelial dysfunction and the activity of repair enzymes in cardiac tissue from a pig model of early atherosclerosis. The study was conducted on 28 female Polish Landrace pigs, weighing 40 kg (approximately 3.5 months old), which were divided into three groups. The control group ( = 11) was fed a standard, commercial, balanced diet (BDG) for 12 months. The second group ( = 9) was fed an unbalanced, high-calorie Western-type diet (UDG). The third group ( = 8) was fed a Western-type diet for nine months and then switched to a standard, balanced diet (regression group, RG). Control examinations, including blood and urine sampling, were conducted every three months under identical conditions with food restriction for 12 h and water restriction for four hours before general anesthesia. The study analyzed markers of oxidative stress formed during lipid peroxidation processes, including etheno DNA adducts, ADMA, and NEFA. These markers play a crucial role in reactive oxygen species analysis in ischemia-reperfusion and atherosclerosis in mammalian tissue. Essential genes involved in oxidative-stress-induced DNA demethylation like OGG1 (8-oxoguanine DNA glycosylase), MPG (N-Methylpurine DNA Glycosylase), TDG (Thymine-DNA glycosylase), APEX (apurinic/apirymidinic endodeoxyribonuclease 1), PTGS2 (prostaglandin-endoperoxide synthase 2), and ALOX (Arachidonate Lipoxygenase) were measured using the Real-Time RT-PCR method. The data suggest that high oxidative stress, as indicated by TBARS levels, is associated with high levels of DNA repair enzymes and depends on the expression of genes involved in the repair pathway. In all analyzed groups of heart tissue homogenates, the highest enzyme activity and gene expression values were observed for the OGG1 protein recognizing the modified 8oxoG. Conclusion: With the long-term use of an unbalanced diet, the levels of all DNA repair genes are increased, especially (significantly) Apex, Alox, and Ptgs, which strongly supports the hypothesis that an unbalanced diet induces oxidative stress that deregulates DNA repair mechanisms and may contribute to genome instability and tissue damage.
Topics: Female; Animals; Swine; DNA Glycosylases; DNA Repair; Atherosclerosis; Oxidative Stress; DNA Adducts; Thymine DNA Glycosylase; DNA Damage; Mammals
PubMed: 38396961
DOI: 10.3390/ijms25042282 -
Nature Communications Feb 2024Most genotoxic anticancer agents fail in tumors with intact DNA repair. Therefore, trabectedin, anagent more toxic to cells with active DNA repair, specifically...
Most genotoxic anticancer agents fail in tumors with intact DNA repair. Therefore, trabectedin, anagent more toxic to cells with active DNA repair, specifically transcription-coupled nucleotide excision repair (TC-NER), provides therapeutic opportunities. To unlock the potential of trabectedin and inform its application in precision oncology, an understanding of the mechanism of the drug's TC-NER-dependent toxicity is needed. Here, we determine that abortive TC-NER of trabectedin-DNA adducts forms persistent single-strand breaks (SSBs) as the adducts block the second of the two sequential NER incisions. We map the 3'-hydroxyl groups of SSBs originating from the first NER incision at trabectedin lesions, recording TC-NER on a genome-wide scale. Trabectedin-induced SSBs primarily occur in transcribed strands of active genes and peak near transcription start sites. Frequent SSBs are also found outside gene bodies, connecting TC-NER to divergent transcription from promoters. This work advances the use of trabectedin for precision oncology and for studying TC-NER and transcription.
Topics: Humans; Trabectedin; Excision Repair; Neoplasms; Transcription, Genetic; Precision Medicine; DNA Repair; DNA Damage; DNA; Nucleotides; DNA Breaks
PubMed: 38360910
DOI: 10.1038/s41467-024-45664-7 -
Nutrients Jan 2024The PHYTOME study investigated the effect of consuming processed meat products on outcomes related to colorectal cancer risk without testing the impact of genetic...
Genetic Variability Impacts Genotoxic and Transcriptome Responses in the Human Colon after the Consumption of Processed Red Meat Products and Those with Added Phytochemical Extracts.
The PHYTOME study investigated the effect of consuming processed meat products on outcomes related to colorectal cancer risk without testing the impact of genetic variability on these responses. This research aims to elucidate the genetic impact on apparent total N-nitroso compound (ATNC) excretion, colonic DNA adduct formation, ex vivo-induced DNA damage, and gene expression changes in colon biopsies of healthy participants. Through a systematic literature review, candidate polymorphisms were selected and then detected using TaqMan and PCR analysis. The effect of genotype on study outcomes was determined via a linear mixed model and analysis of variance. Machine learning was used to evaluate relative allele importance concerning genotoxic responses, which established a ranking of the most protective alleles and a combination of genotypes (gene scores). Participants were grouped by GSTM1 genotype and differentially expressed genes (DEGs), and overrepresented biological pathways were compared between groups. Stratifying participants by ten relevant genes revealed significant variations in outcome responses. After consumption of processed red meat, variations in NQO1 and COMT impacted responses in ATNC levels (µmol/L) (+9.56 for wildtype vs. heterozygous) and DNA adduct levels (pg/µg DNA) (+1.26 for variant vs. wildtype and +0.43 for variant vs. heterozygous), respectively. After phytochemicals were added to the meat, GSTM1 variation impacted changes in DNA adduct levels (-6.12 for deletion vs. wildtype). The gene scores correlated with these responses and DEGs were identified by GSTM1 genotype. The altered pathways specific to the GSTM1 wildtype group included 'metabolism', 'cell cycle', 'vitamin D receptor', and 'metabolism of water-soluble vitamins and co-factors'. Genotype impacted both the potential genotoxicity of processed red meat and the efficacy of protective phytochemical extracts.
Topics: Humans; Meat Products; DNA Adducts; Transcriptome; DNA Damage; Meat; Red Meat; Nitroso Compounds; Colon
PubMed: 38337709
DOI: 10.3390/nu16030425 -
Heliyon Jan 2024Aflatoxin B (AFB) is a secondary metabolite produced principally by and . It is one of the most potent and commonly occurring dietary carcinogen with its carcinogenic...
Aflatoxin B (AFB) is a secondary metabolite produced principally by and . It is one of the most potent and commonly occurring dietary carcinogen with its carcinogenic potential being linked to the formation of DNA adducts and reactive oxygen species (ROS). Plant extracts contain a plethora of biologically active phytochemicals that act against ROS. This study aimed to assess the phytochemical content and antioxidant activity of methanolic extracts of some medicinal plants and investigate their detoxification potentials against AFB. Phytochemical screening together with total phenolic content (TPC), total flavonoid content (TFC), and antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)) assays) were performed on nine methanolic plant extracts. Extracts were incubated with AFB for 24 and 48 h and liquid chromatography mass spectrometry (LC-MS) analysis done to assess their AFB detoxification activities. The TPC of the extracts ranged from 88.92 ± 6.54 to 210.19 ± 7.90 mg GAE/g, while TFC ranged between 4.01 ± 0.94 and 32.48 ± 1.02 mg QE/g. Radical scavenging activities of extracts varied from 4.18 ± 1.37 to 251.53 ± 9.30 μg/mL and 8.36 ± 1.65 to 279.22 ± 8.33 μg/mL based on DPPH and ABTS assays, respectively. Six of the plant extracts showed a time-dependent detoxification activity against AFB after 48 h ranging from 20.17 to 38.13 %. bark extract showed the highest percentage of AFB reduction, with mean percentages of 43.57 and 70.96 % at 24 and 48 h, respectively. This was followed by leaves and seeds with a maximum of 40.81 and 38.13 %, respectively after 48 h. These extracts also possessed high TPC, TFC, and antioxidant activities compared to all the other extracts. Findings from this study demonstrate the abundance of bioactive compounds with antioxidant activity playing a role in potent AFB detoxification activity.
PubMed: 38312698
DOI: 10.1016/j.heliyon.2024.e24435