OBJECTIVES: To investigate the effects and mechanisms of deubiquitinating enzyme Josephin domain containing 2 (JOSD2) on susceptibility of non-small cell lung carcinoma (NSCLC) cells to anti-cancer drugs. METHODS: The transcriptome expression and clinical data of NSCLC were downloaded from the Gene Expression Omnibus. Principal component analysis and limma analysis were used to investigate the deubiquitinating enzymes up-regulated in NSCLC tissues. Kaplan-Meier analysis was used to investigate the relationship between the expression of deubiquitinating enzymes and overall survival of NSCLC patients. Gene ontology enrichment and gene set enrichment analysis (GSEA) were used to analyze the activation of signaling pathways in NSCLC patients with high expression of JOSD2. Gene set variation analysis and Pearson correlation were used to investigate the correlation between JOSD2 expression levels and DNA damage response (DDR) pathway. Western blotting was performed to examine the expression levels of JOSD2 and proteins associated with the DDR pathway. Immunofluorescence was used to detect the localization of JOSD2. Sulforhodamine B staining was used to examine the sensitivity of JOSD2-knock-down NSCLC cells to DNA damaging drugs. RESULTS: Compared with adjacent tissues, the expression level of JOSD2 was significantly up-regulated in NSCLC tissues (P<0.05), and was significantly correlated with the prognosis in NSCLC patients (P<0.05). Compared with the tissues with low expression of JOSD2, the DDR-related pathways were significantly upregulated in NSCLC tissues with high expression of JOSD2 (all P<0.05). In addition, the expression of JOSD2 was positively correlated with the activation of DDR-related pathways (all P<0.01). Compared with the control group, overexpression of JOSD2 significantly promoted the DDR in NSCLC cells. In addition, DNA damaging agents significantly increase the nuclear localization of JOSD2, whereas depletion of JOSD2 significantly enhanced the sensitivity of NSCLC cells to DNA damaging agents (all P<0.05). CONCLUSIONS Deubiquitinating enzyme JOSD2 may regulate the malignant progression of NSCLC by promoting DNA damage repair pathway, and depletion of JOSD2 significantly enhances the sensitivity of NSCLC cells to DNA damaging agents.
Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Antineoplastic Agents/pharmacology* ; Lung Neoplasms/genetics* ; DNA Damage ; DNA ; Deubiquitinating Enzymes/genetics*

Eukaryotic organisms constantly face a wide range of internal and external factors that cause damage to their DNA. Failure to accurately and efficiently repair these DNA lesions can result in genomic instability and the development of tumors (Canela et al., 2017). Among the various forms of DNA damage, DNA double-strand breaks (DSBs) are particularly harmful. Two major pathways, non-homologous end joining (NHEJ) and homologous recombination (HR), are primarily responsible for repairing DSBs (Katsuki et al., 2020; Li and Yuan, 2021; Zhang and Gong, 2021; Xiang et al., 2023). NHEJ is an error-prone repair mechanism that simply joins the broken ends together (Blunt et al., 1995; Hartley et al., 1995). In contrast, HR is a precise repair process. It involves multiple proteins in eukaryotic cells, with the RAD51 recombinase being the key player, which is analogous to bacterial recombinase A (RecA) (Shinohara et al., 1992). The central event in HR is the formation of RAD51-single-stranded DNA (ssDNA) nucleoprotein filaments that facilitate homology search and DNA strand invasion, ultimately leading to the initiation of repair synthesis (Miné et al., 2007; Hilario et al., 2009; Ma et al., 2017).
Recombinational DNA Repair ; DNA-Binding Proteins/metabolism* ; DNA Repair ; DNA Damage ; DNA

Animals ; Mice ; DNA Repair ; DNA Breaks, Double-Stranded ; DNA/metabolism* ; DNA Damage

Objectives: To study the association between metals mixture exposure and DNA oxidative damage using mixture analysis methods, and to explore the most significant exposure factors that cause DNA oxidative damage. Methods: Workers from steel enterprises were recruited in Shandong Province. Urinary metals were measured by using the inductively coupled plasma mass spectrometry method. The level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was determined by using the ultra-high performance liquid chromatography-mass spectrometry method. Bayesian kernel machine regression (BKMR), elastic net regression and quantile g-computation regression were used to analyze the association between urinary metals and urinary 8-OHdG. Results: A total of 768 subjects aged (36.15±7.40) years old were included in the study. BKMR, elastic net regression and quantile g-computation all revealed an overall positive association between the mixture concentration and increased urinary 8-OHdG. The quantile g-computation results showed that with a 25% increase in metal mixtures, the urinary 8-OHdG level increased by 77.60%. The elastic net regression showed that with a 25% increase in exposure risk score, the urinary 8-OHdG level increased by 26%. The BKMR summarized the contribution of individual exposures to the response, and selenium, zinc, and nickel were significant contributors to the urinary 8-OHdG elevation. Conclusion: Exposure to mixed metals causes elevated levels of DNA oxidative damage, and selenium, zinc, and nickel are significant exposure factors.
Humans ; Adult ; Nickel/toxicity* ; Selenium ; Bayes Theorem ; Metals/toxicity* ; 8-Hydroxy-2'-Deoxyguanosine ; Oxidative Stress/physiology* ; Zinc ; DNA Damage

OBJECTIVE: The study aimed to estimate the benchmark dose (BMD) of coke oven emissions (COEs) exposure based on mitochondrial damage with the mitochondrial DNA copy number (mtDNAcn) as a biomarker. METHODS: A total of 782 subjects were recruited, including 238 controls and 544 exposed workers. The mtDNAcn of peripheral leukocytes was detected through the real-time fluorescence-based quantitative polymerase chain reaction. Three BMD approaches were used to calculate the BMD of COEs exposure based on the mitochondrial damage and its 95% confidence lower limit (BMDL). RESULTS: The mtDNAcn of the exposure group was lower than that of the control group (0.60 ± 0.29 vs. 1.03 ± 0.31; P < 0.001). A dose-response relationship was shown between the mtDNAcn damage and COEs. Using the Benchmark Dose Software, the occupational exposure limits (OELs) for COEs exposure in males was 0.00190 mg/m ³. The OELs for COEs exposure using the BBMD were 0.00170 mg/m ³ for the total population, 0.00158 mg/m ³ for males, and 0.00174 mg/m ³ for females. In possible risk obtained from animal studies (PROAST), the OELs of the total population, males, and females were 0.00184, 0.00178, and 0.00192 mg/m ³, respectively. CONCLUSION Based on our conservative estimate, the BMDL of mitochondrial damage caused by COEs is 0.002 mg/m ³. This value will provide a benchmark for determining possible OELs.
Male ; Female ; Animals ; Coke ; Polycyclic Aromatic Hydrocarbons ; DNA Copy Number Variations ; Benchmarking ; Occupational Exposure/analysis* ; DNA, Mitochondrial/genetics* ; DNA Damage

Objective: To investigate the correlation between adjuvant chemotherapy with platinum-containing regimens and DNA damage repair (DDR) defects in early-stage triple negative breast cancer (TNBC), and to provide a basis for precise treatment of TNBC. Methods: Next-generation sequencing (NGS) testing was performed on postoperative breast cancer specimens selected from the Cancer Hospital of Chinese Academy of Medical Sciences from June 2009 to October 2015 to analyze the correlation between DDR gene variants and the efficacy of adjuvant chemotherapy with TNBC platinum-containing regimens, and thus to screen the superior population for adjuvant chemotherapy with TNBC platinum-containing regimens. The study used t-test, χ(2) test, Fisher's exact test, rank sum test and multifactorial logistic analysis to assess the associations between mutated genes and clinicopathological characteristics and prognosis, and Log-rank test and Cox proportional risk model were used for survival and correlation analysis. Results: NGS results were successfully obtained in 149 patients (74 in the platinum-containing group and 75 in the platinum-free group), with a 97.3% (145/149) DDR gene mutation rate and a median number of 4 mutations in all patients. 5-year disease-free survival (DFS) was 85.4% and 75.0% for patients with DDR gene mutations and DDR gene wild-type, respectively, without statistical difference (P=0.825). The 5-year DFS rates of patients with homologous recombination repair (HRR) pathway mutation were 84.6% in platinum-containing (TCb) group and 84.9% in platinum-free (EC-T) group (P=0.554), respectively. The 5-year DFS rates of patients with and without mutations in the platinite-containing HRR pathway were 84.9% and 85.0%, respectively (P=0.751). The number of DDR pathways with mutations and the number of DDR gene mutations were not associated with prognosis (both P>0.05). PIK3CA mutation patients in TCb group had a worse prognosis than wild-type patients (5-year DFS were 71.4% and 88.1%, P=0.037), and KMT2D mutation patients in EC-T group had a worse prognosis than wild-type patients (5-year DFS were 76.9% and 86.8%, P=0.039). Conclusions: DDR gene variation is common in TNBC, more clinical studies are needed to prove whether DDR variation can serve as effective biomarkers for treatment with platinum.
Humans ; Triple Negative Breast Neoplasms/pathology* ; DNA Repair ; Mutation ; Combined Modality Therapy ; DNA Damage

Objective: To investigate the correlation between adjuvant chemotherapy with platinum-containing regimens and DNA damage repair (DDR) defects in early-stage triple negative breast cancer (TNBC), and to provide a basis for precise treatment of TNBC. Methods: Next-generation sequencing (NGS) testing was performed on postoperative breast cancer specimens selected from the Cancer Hospital of Chinese Academy of Medical Sciences from June 2009 to October 2015 to analyze the correlation between DDR gene variants and the efficacy of adjuvant chemotherapy with TNBC platinum-containing regimens, and thus to screen the superior population for adjuvant chemotherapy with TNBC platinum-containing regimens. The study used t-test, χ(2) test, Fisher's exact test, rank sum test and multifactorial logistic analysis to assess the associations between mutated genes and clinicopathological characteristics and prognosis, and Log-rank test and Cox proportional risk model were used for survival and correlation analysis. Results: NGS results were successfully obtained in 149 patients (74 in the platinum-containing group and 75 in the platinum-free group), with a 97.3% (145/149) DDR gene mutation rate and a median number of 4 mutations in all patients. 5-year disease-free survival (DFS) was 85.4% and 75.0% for patients with DDR gene mutations and DDR gene wild-type, respectively, without statistical difference (P=0.825). The 5-year DFS rates of patients with homologous recombination repair (HRR) pathway mutation were 84.6% in platinum-containing (TCb) group and 84.9% in platinum-free (EC-T) group (P=0.554), respectively. The 5-year DFS rates of patients with and without mutations in the platinite-containing HRR pathway were 84.9% and 85.0%, respectively (P=0.751). The number of DDR pathways with mutations and the number of DDR gene mutations were not associated with prognosis (both P>0.05). PIK3CA mutation patients in TCb group had a worse prognosis than wild-type patients (5-year DFS were 71.4% and 88.1%, P=0.037), and KMT2D mutation patients in EC-T group had a worse prognosis than wild-type patients (5-year DFS were 76.9% and 86.8%, P=0.039). Conclusions: DDR gene variation is common in TNBC, more clinical studies are needed to prove whether DDR variation can serve as effective biomarkers for treatment with platinum.
Humans ; Triple Negative Breast Neoplasms/pathology* ; DNA Repair ; Mutation ; Combined Modality Therapy ; DNA Damage

DNA ; DNA Damage ; DNA Repair ; Fanconi Anemia/genetics* ; Humans

Objective: SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase (KMT) that monomethylates lysine 20 of histone H4 (H4K20me1). SET8 has been implicated in many essential cellular processes, including cell cycle regulation, DNA replication, DNA damage response, and carcinogenesis. There is no conclusive evidence, however, regarding the effect of SET8 on radiotherapy. In the current study we determined the efficacy of SET8 inhibition on radiotherapy of tumors and the underlying mechanism. Methods: First, we explored the radiotherapy benefit of the SET8 expression signature by analyzing clinical data. Then, we measured a series of biological endpoints, including the xenograft tumor growth in mice and apoptosis, frequency of micronuclei, and foci of 53BP1 and γ-H2AX in cells to detect the SET8 effects on radiosensitivity. RNA sequencing and subsequent experiments were exploited to verify the mechanism underlying the SET8 effects on radiotherapy. Results: Low expression of SET8 predicted a better benefit to radiotherapy in lung adenocarcinoma (LUAD) and invasive breast carcinoma (BRCA) patients. Furthermore, genetic deletion of SET8 significantly enhanced radiation treatment efficacy in a murine tumor model, and A549 and MCF7 cells; SET8 overexpression decreased the radiosensitivity. SET8 inhibition induced more apoptosis, the frequency of micronuclei, and blocked the kinetics process of DNA damage repair as 53BP1 and γ-H2AX foci remained in cells. Moreover, RNF8 was positively correlated with the SET8 impact on DNA damage repair. Conclusion Our results demonstrated that SET8 inhibition enhanced radiosensitivity by suppressing DNA damage repair, thus suggesting that SET8 potentiated radiotherapy of carcinomas. As new inhibitors of SET8 are synthesized and tested in preclinical and clinical settings, combining SET8 inhibitors with radiation warrants consideration for precise radiotherapy.
Animals ; Apoptosis ; Carcinogenesis ; Carcinoma/radiotherapy* ; Cell Cycle ; Cell Line, Tumor ; DNA Damage ; DNA Replication ; HeLa Cells ; Histone-Lysine N-Methyltransferase ; Humans ; Mice ; Radiotherapy

Objective: To investigate the protective effect of diallyl sulfide (DAS) , against benzene-induced genetic damage in rat. Methods: In September 2018, Sixty adult male adaptive feeding 5 days, were randomly divided into six groups according to their weight. Control groups, DAS control groups, benzene model groups, benzene+low DAS groups, benzene+middle DAS groups, benzene+High DAS group, 10 in each group. Rats in the DAS and DAS control group were orally given DAS at 40, 80, 160, 160 mg/kg, blank control and benzene model groups were given corn oil in the same volume. 2 h later, the rats in the benzene model and DAS treatment groups were given gavage administration of benzene (1.3 g/kg) mixed with corn oil (50%, V/V) , blank and DAS control groups were given corn oil in the same volume. Once a day, for 4 weeks. Samples were collected for subsequent testing. Results: Compared with the blank control group, In benzene treated rat, peripheral WBC count was reduced 65.06% (P=0.003) , lymphocyte ratiowas reduced (P=0.000) , micronucleus rate was increased (P=0.000) , Mean fluorescent intensity and relative fluorescence intensity of γH2AX in BMCs were increased 32.69%、32.64% (P=0.001、0.008) , Mean fluorescent intensity and relative fluorescence intensity of γH2AX in PBLs were increased 397.70%、396.26% (P=0.000、P=0.003) respectively. Compared with the benzene model group, the WBC count increased respectively (P=0.000、0.003、0.006) and the micronucleus rate decreased (P=0.000、0.000、0.000) in the DAS groups, Mean fluorescent intensity and relative fluorescence intensity ofγH2AX in BMCs were significantly reduced in the high DAS groups (P=0.000、0.000) , Mean fluorescent intensity and relative fluorescence intensity ofγH2AX in PBLs were significantly reduced in the low, middle, high DAS groups (P=0.000、0.000) . Conclusion: DAS can effectively suppress benzene induced genotoxic damage in rats.
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid/analogs & derivatives* ; Allyl Compounds/pharmacology* ; Animals ; Benzene/toxicity* ; Corn Oil ; DNA Damage ; Male ; Rats ; Sulfides/pharmacology*