Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis最新文献

Apiole (1-allyl-2,5-dimethoxy-3,4-methylenedioxybenzene) and parsley leaves ethanolic extract containing it inhibit the rat liver microsomal ethoxy- and methoxyresorufin-O-deacetylase activities associated with cytochrome P450 (CYP) 1A1 and 1A2, respectively. Cytochrome P4501A subfamily metabolizes environmental mutagens and several drugs, leading to the formation of mutagenic metabolites. Docking analysis showed that residue Phe123 within the active site of the CYP1A1 enzyme is bound to apiole through a π/π stacking of its benzene ring. In the case of 1A2, its Phe226 interacts with the dioxolane ring of apiole. Furthermore, apiole behaves as a mixed-type inhibitor of bacterial human recombinant CYP1A1. To explore one of the possible biological implications of this inhibitory effect, we tested the capacity of apiole and the parsley ethanolic extract to interfere with the mutagenicity of the promutagen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) metabolized by CYP1A subfamily. As expected, both apiole and the plant extract reduced the number of revertant colonies of Salmonella typhimurium TA98 Ames strain after exposure to MeIQx, reaching a 78 % and 100 % reduction, respectively. Neither apiol nor parsley extract were mutagenic to the TA98 strain. We speculate that consuming apiole, a constituent of edible herbs, in conjunction with the utilization of pharmaceuticals metabolized by the CYP1A subfamily, may result in herb-drug interactions. Furthermore, the consumption of apiole by individuals who regularly ingest fresh vegetables may contribute to the low incidence of cancer observed in those who adhere to such a dietary regimen.

Homologous recombination (HR) is essential for repair of DNA double-strand breaks (DSBs) and restart of stalled or collapsed replication forks. Most cancers are characterized by mutations in components of the DSB repair pathways. Redundant DSB repair pathways exist in eukaryotes from yeast to humans and recent evidence has shown that complete loss of HR function appears to be lethal. Recent evidence has also shown that cancer cells with mutations in one DSB repair pathway can be killed by inhibiting one or more parallel pathways, a strategy that is currently aggressively explored as a cancer therapy. KDM4B is a histone demethylase with pleiotropic functions, which participates in preparing DSBs for repair by contributing to chromatin remodeling. In this report we carried out a pan-cancer analysis of KDM4B mutations with the goal of understanding their distribution and interaction with other DSB genes. We find that although KDM4B mutations co-occur with DSB repair genes, most KDM4B mutations are not drivers or pathogenic. A sequence conservation analysis from yeast to humans shows that highly conserved residues are resistant to mutation. Finally, all mutations occur in a heterozygous state. A single mutation, R986L, was predicted to significantly affect protein structure using computational modeling. This analysis suggests that KDM4B makes contributions to DSB repair but is not a key player.

Objective

This study aimed to explore the role of heat shock protein family E member 1 (HSPE1) in the metabolism of lung adenocarcinoma (LUAD) cells.

Methods

Bioinformatics analysis was applied to examine the expression of HSPE1 in LUAD and its correlation with patient survival. Single-gene Gene Set Enrichment Analysis was conducted for HSPE1. LUAD cell lines or mouse models with up-regulated/down-regulated HSPE1 were constructed. The expression level of HSPE1 was detected by qRT-PCR or immunohistochemical staining. We used CCK-8 assay to measure cell viability and flow cytometry to detect apoptosis levels. Transwell assay was performed to evaluate migration and invasion characteristics. Extracellular Flux Analyzer was employed to detect oxygen consumption rate and extracellular acidification rate. Glucose consumption, adenosine triphosphate production, and lactate levels were measured by Reagent kits. Western blot analysis was conducted to examine the expression levels of GLUT1, HK2, and LDHA.

Results

HSPE1 promoted proliferative, migratory, and invasive abilities, and inhibited apoptosis of LUAD cells through the aerobic glycolysis pathway. Specifically, LUAD cells with HSPE1 knockdown exhibited significantly decreased proliferation, migration, and invasion abilities, along with an increased apoptosis rate. Additionally, the expression levels of aerobic glycolysis-related proteins HK2, LADH, and GLUT1 were downregulated, while their levels were increased in LUAD cells with high HSPE1 expression. Suppression of aerobic glycolysis by 2-DG attenuated the promoting effects of HSPE1 overexpression on the proliferation, migration, and invasion of LUAD cells. HSPE1 knockdown inhibited tumor growth and decreased expression levels of HK2, LADH, and GLUT1 in vivo.

Conclusion

HSPE1 regulated the proliferation, migration, and invasion of LUAD cells through the aerobic glycolysis pathway, thus facilitating malignant development of LUAD. The study suggested that HSPE1 could be useful as a therapeutic target for LUAD.

Background

Ovarian cancer (OC) is a frequent malignancy of the female reproductive system. Recently, the aberrant expression of numerous lncRNAs has been confirmed as a key factor for cancer development. The regulatory role of PAX8-AS1 in some cancers has been investigated, but its role in OC progression remains unclear. This study focuses on the role and molecular mechanism of PAX8-AS1 in the malignant progression of OC.

Methods

Bioinformatics means were adopted to analyze the expression of PAX8-AS1, microRNA-25–3p, and LATS2 in OC tissues and the binding sites between the three. qRT-PCR was employed to determine the expression of these genes in OC cells. CCK-8, colony formation, scratch healing, and Transwell assays were used to see cell viability, proliferation, migration, and invasion, respectively. Fluorescence in situ Hybridization was performed to probe the subcellular localization of PAX8-AS1. Western blot was applied to evaluate the expression and phosphorylation levels of YAP and TAZ, and an immunofluorescence assay was used to detect the translocation of them. Dual luciferase assay was applied to validate the binding relationship between PAX8-AS1 and microRNA-25–3p, as well as between microRNA-25–3p and LATS2.

Results

PAX8-AS1 and LATS2 were lowly expressed. MicroRNA-25–3p was highly expressed in OC. PAX8-AS1 was expressed in cytoplasm and regulated LATS2 expression by sponging microRNA-25–3p. Overexpressing PAX8-AS1 can suppress the malignant behaviors of OC cells, whereas treatment with microRNA-mimic can reverse these results. In addition, the phosphorylation levels of YAP and TAZ increased upon oe-LATS2 treatment, and oe-LATS2 could promote YAP and TAZ translocate from the nucleus to cytoplasm. Rescue experiments demonstrated that sh-PAX8-AS1 fostered malignant progression of OC, which was reversed by simultaneous oe-LATS2.

Conclusion

In summary, PAX8-AS1/microRNA-25–3p/LATS2 regulated the malignant progression of OC through Hippo signaling, which suggested that PAX8-AS1/microRNA-25–3p/LATS2 axis may be a novel target for OC treatment.

Environmental and occupational exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with adverse health effects in humans. Uncertainty exists regarding the causation of urinary bladder cancer by benzo[a]pyrene (B[a]P) due to a lack of sufficient data. In this work, we focused on in-vitro DNA damage and the formation of micronuclei and chromosomal aberrations as predictors of cancer risk, applying a wide range of dosages and time periods to quantify the onset, intensity, and duration of the response. We chose two urothelial cell types to compare susceptibility and the ability to increase the malignity of a pre-existing bladder cancer: a cancer cell line (T24) and a pooled sample of primary urinary bladder epithelia cells (PUBEC) from pigs. The highest level of DNA damage assessed by comet assay was observed following 24-h treatment in both cell types, whereas PUBEC cells were clearly more susceptible. Even 4-h treatment induced DNA damage in PUBEC cells with benchmark doses of 0.0027 µM B[a]P and 0.00023 µM after 4-h and 24-h exposure, respectively. Nearly no effect was observed for periods of 48 h. The frequency of micronucleus formation increased more markedly in T24 cells, particularly with 24-h treatment. In PUBEC cells, 48-h exposure notably induced the formation of nucleoplasmic bridges and nuclear buds. Even though only one biological replicate was studied due to the sophisticated study design, our results give a strong indication of the potential of B[a]P to induce and increase malignity in human-relevant cell types.

In vitro mutation breeding in vegetatively propagated crops like banana offers a benefit in screening for beneficial variants in plant cells or cultured tissues. An attempt was made to induce mutants and determine the lethal dose, as it is the prerequisite to optimize the concentration and duration of the mutagen used to recover a larger population in mutation research. Shoot tip cultures were treated for 2 and 4 h at six different EMS concentrations ranging from 80 mM to 160 mM, whereas proliferating multiple shoots were exposed for 30 and 60 min at six different EMS concentrations ranging from 8 mM to 40 mM. Survival percentage, shoot length, and number of shoots reduced linearly and significantly as concentration and duration increased in both shoot tips and proliferating multiple buds. The probit curve-based analysis of mortality of treated explants revealed that the LD₅₀ was 155.83 mM for 2 h and 113.72 mM for 4 h, respectively for shoot tip cultures, whereas for proliferating multiple buds, the LD₅₀ value was adjusted to 39.11 mM for 30 min and 30.41 mM for 60 min. 160 mM EMS for 4 h resulted in a shorter shoot, a longer rooting duration, a lesser number of roots, and decreased root development. In proliferating multiple shoots, the smallest shoot, longest rooting duration, least number of roots, and shortest root were observed in 40 mM EMS for 60 min. Similar reductions in growth parameters were observed in proliferating multiple shoots at higher exposure to EMS for a longer duration.

Lung cancer is the one of the most prevalent cancer in the world. It kills more people from cancer than any other cause and is especially common in underdeveloped nations. With 1.2 million instances, it is also the most prevalent cancer in men worldwide, making about 16.7% of the total cancer burden. Surgery is the main form of curative treatment for early-stage lung cancer. However, the majority of patients had incurable advanced non-small cell lung cancer (NSCLC) recurrence after curative purpose surgery, which is indicative of the aggressiveness of the illness and the dismal outlook. The gold standard of treatment for NSCLC patients includes drug targeting of specific mutated genes drive in development of lung cancer. Furthermore, patients with advanced NSCLC and those with early-stage illness needing adjuvant therapy should use cisplatin as it is the more active platinum drug. So, this review encompasses the non-small cell lung cancer microenvironment, treatment approaches, and use of cisplatin as a first-line regimen for NSCLC, its mechanism of action, cisplatin resistance in NSCLC and also the prevention strategies to revert the drug resistance.

Inhaled anesthetics, such as isoflurane, may cause side effects, including short-term immunosuppression and DNA damage. In contrast, low molecular weight fucoidan (LMF), derived from brown seaweed, exhibits promising immunomodulatory effects. In this study, we determined the effect of isoflurane on telomeres and examined the potential of LMF to ameliorate the harmful effects of isoflurane. Male Lewis rats, the mouse lymphoma cell line YAC-1, and the human nature killer cell line NK-92 MI were exposed to isoflurane. The relative telomere length (T/S) ratio and mRNA expression were determined by quantitative PCR. The viability assay was used to assess cell viability. In vivo, 2% isoflurane exposure, which is a clinically relevant concentration, reduced telomere length, and correlated with exposure frequency and duration. Isoflurane concentrations above 2% shortened YAC-1 telomeres, with minimal impact on cell viability. LMF pre-treatment enhanced NK-92 MI cell survival resulting from isoflurane exposure and exerted superior telomere protection compared with LMF post-treatment. Furthermore, adding LMF during isoflurane exposure resulted in a significant increase in IFN-γ, TNF-α, and IL-10 mRNA compared with the untreated group. LMF protected against isoflurane-induced telomere shortening, enhanced NK cell viability, and modulated cytokine expression, thus mitigating postoperative immune suppression and risk of tumor metastasis.

Background/objective

H. pylori is a recognized bacterial carcinogen in the world to cause gastric cancer (GC). However, the molecular mechanism of H. pylori infection-induced GC is not completely clear. Thus, there is an urgent need to reveal the precise mechanisms regulating cancer development due to H. pylori infection.

Methods

GEO microarray databases and TCGA databases were extracted for the analysis of different expression genes (DEGs). Then, Kaplan-Meier Plotter was used for prognostic analysis. Functional enrichment analysis of TRIP13 was performed by metascape database and TIMER database. Specific role of TRIP13 in GC with H. pylori infection was confirmed by CCK8, cell cycle analysis and WB.

Results

A total 10 DEGs were substantially elevated in GC and H. pylori+ tissues and might be associated with H. pylori infection in GC and only the highly expressed TRIP13 was statistically associated with poor prognosis in GC patients. Meanwhile, TRIP13 were upregulated in both CagA-transfected epithelial cells and GC cells. And TRIP13 deficiency inhibited cell proliferation and arrested the cell cycle at the G1 phase.

Conclusion

Our study suggested that high expression of TRIP13 can promote the proliferation, cell cycle in GC cells, which could be used as a biomarker for H. pylori infection GC.

The widespread use of chemicals and the presence of chemical and metal residues in various foods, beverages, and other consumables have raised concerns about the potential for enhanced toxicity. This study assessed the cytotoxic effects of Piperonyl butoxide (PBO) and its enhancement by combination with major contamination chemicals including Imidacloprid and metals, using different cytotoxic and genotoxic assays in Chinese hamster ovary (CHO) cells. PBO exhibited elevated cytotoxic effects in poly (ADP-ribose) polymerase (PARP) deficient CHO mutants but not in Glutathione S-transferase deficient CHO mutants. PBO cytotoxicity was enhanced by PARP inhibitor, Olaparib. PBO cytotoxicity was also enhanced with co-exposure to Imidacloprid, Lead Chloride, or Sodium Selenite. PBO induces γH2AX foci formation and apoptosis. The induction of DNA damage markers was elevated with PARP deficiency and co-exposure to Imidacloprid, Lead Chloride, or Sodium Selenite. Moreover, PBO triggers to form etch pits on plastic surfaces. These results revealed novel mechanisms of PBO cytotoxicity associated with PARP and synergistic effects with other environmental pollutants. The toxicological mechanisms underlying exposure to various combinations at different concentrations, including concentrations below the permitted limit of intake or the level of concern, require further study.