Using haplotype analysis to elucidate significant associations between genes and Hodgkin lymphoma.

In this study, we estimated the association between the inferred haplotypes in the inflammation, DNA repair, and folate pathways, and developed risk models for Hodgkin lymphoma. The study population consisted of 200 Hodgkin lymphoma cases and 220 controls. A susceptible association was observed on the XPC gene with haplotype CT (rs2228001 and rs2228000), and a protective association was observed on the IL4R gene with haplotype TCA (rs1805012, rs1805015, and rs1801275). These results can provide the necessary tools to identify high-risk individuals after validation in large data sets.

Circadian aspects of hyperthermia in mice induced by Aconitum napellus.

BACKGROUND: Aconitum napellus (Acn) is used topically to relieve pain, itching and inflammation, and internally to reduce febrile states, among others. Any circadian time-related consequences of Acn administration are unknown. The objective of this study was to explore the effects of two doses of Acn on body temperature (BT) of mice treated at six different times over 24 hours. MATERIALS AND METHODS: BALB/c female mice were housed in six chambers (six mice each) with air temperature 24 ± 3°C, humidity 60 ± 4%, and a 12-hours light (L)/12-hours dark cycle, but with L-onset staggered by 4 hours between chambers so that study at one external test time resulted in six test times (02, 06, 10, 14, 18 and 22 hours [h] after light onset). Rectal temperature (RT; in °C) was measured at baseline (B) and 1 hour after oral treatment with placebo (P) or two doses of Acn (6C and 30C, two studies each) in six studies over an 8 day span. The difference in RT for each mouse from the respective B + P timepoint mean RT was computed following each Acn treatment, and data from each of the six studies (original RT and difference from B + P) were analyzed for time-effect by analysis of variance (ANOVA) and for circadian rhythm by 24-hour cosine fitting. RESULTS: A CIRCADIAN RHYTHM IN RT WAS FOUND AT B AND AFTER P (MEAN: 35.58°C vs. 35.69°C; peak: 15:31 h vs. 15:40 h) and after each Acn dose (30C or 6C). Acn induced hyperthermia and the overall change in BT was rhythmically significant for each dose (mean = +1.95°C vs. +1.70°C), with greatest hyperthermia observed during the L-span for each dose (peak = 08:56 h vs. 05:17 h). CONCLUSION: Acn administered around the clock induced hyperthermia overall and in a time-dependent manner, with greatest effects during the resting (L) span. Thus, time of day may significantly impact the outcome of Acn and other homeopathic treatments and should be considered in determining optimal dosing and treatment time(s) in order to increase the desired outcome and decrease undesired effects.

Hodgkin lymphoma risk: role of genetic polymorphisms and gene-gene interactions in DNA repair pathways.

DNA repair variants may play a potentially important role in an individual's susceptibility to developing cancer. Numerous studies have reported the association between genetic single nucleotide polymorphisms (SNPs) in DNA repair genes and different types of hematologic cancers. However, to date, the effects of such SNPs on modulating Hodgkin lymphoma (HL) risk have not yet been investigated. We hypothesized that gene-gene interaction between candidate genes in direct reversal, nucleotide excision repair (NER), base excision repair (BER) and double strand break (DSB) pathways may contribute to susceptibility to HL. To test this hypothesis, we conducted a study on 200 HL cases and 220 controls to assess associations between HL risk and 21 functional SNPs in DNA repair genes. We evaluated potential gene-gene interactions and the association of multiple polymorphisms in a chromosome region using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction and classification and regression tree approaches. We observed that, in combination, allelic variants in the XPC Ala499Val, NBN Glu185Gln, XRCC3 Thr241Me, XRCC1 Arg194Trp, and XRCC1 399Gln polymorphisms modify the risk for developing HL. Moreover, the cumulative genetic risk score revealed a significant trend where the risk for developing HL increases as the number of adverse alleles in BER and DSB genes increase. These findings suggest that DNA repair variants in BER and DSB pathways may play an important role in the development of HL.

Variants in folate pathway genes as modulators of genetic instability and lung cancer risk.

Genetic instability plays a crucial role in cancer development. The genetic stability of the cell as well as DNA methylation status could be modulated by folate levels. Several studies suggested associations between polymorphisms in folate genes and alterations in protein expression and variations in serum levels of the folate. The objective of this study was to investigate the effect of folate pathway polymorphisms on modulating genetic instability and lung cancer risk. Genotyping of 5 SNPs in folate pathway genes and cytokinesis-blocked micronucleus cytome assay analysis (to determine the genetic instability at baseline and following NNK treatment) was conducted on 180 lung cancer cases and 180 age-, gender-, and smoking-matched controls. Our results showed that individually, folate pathway SNPs were not associated with cytogenetic damage or lung cancer risk. However, in a polygenic disease such as lung cancer, gene-gene interactions are expected to play an important role in determining the phenotypic variability of the diseases. We observed that interactions between MTHFR677, MTHFR1298, and SHMT polymorphisms may have a significant impact on genetic instability in lung cancer patients. With regard to cytogenetic alterations, our results showed that lymphocytes from lung cancer patients exposed to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [NNK] had considerably increased frequency of cytogenetic damage in presence of MTHFR 677, MTHFR 1298, and SHMT allelic variants. These findings support the notion that significant interactions may potentially modulate the lung cancer susceptibility and alter the overall the repair abilities of lung cancer patients when exposed to tobacco carcinogens such as NNK.

Hodgkin disease risk: role of genetic polymorphisms and gene-gene interactions in inflammation pathway genes.

Inflammation is a critical component of cancer development. The clinical and pathological features of Hodgkin disease (HD) reflect an abnormal immunity that results from cytokines secreted by Reed-Sternberg cells and the surrounding tumor. Numerous studies have reported the association between genetic polymorphisms in cytokine genes and the susceptibility to different hematologic cancers. However, the effects of such SNPs on modulating HD risk have not yet been investigated. We hypothesized that gene-gene interactions between candidate genes in the anti- and pro-inflammatory pathways carrying suspicious polymorphisms may contribute to susceptibility to HD. To test this hypothesis, we conducted a study on 200 HD cases and 220 controls to assess associations between HD risk and 38 functional SNPs in inflammatory genes. We evaluated potential gene-gene interactions using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction, and classification and regression tree (CART) approaches. We observed that, in combination, allelic variants in the COX2, IL18, ILR4, and IL10 genes modify the risk for developing HD. Moreover, the cumulative genetic risk score (CGRS) revealed a significant trend where the risk for developing HD increases as the number of adverse alleles in the cytokine genes increase. These findings support the notion that epigenetic-interactions between these cytokines may influence pathogenesis of HD modulating the proliferation of regulatory T cells. In this way, the innate and adaptative immune responses may be altered and defy their usual functions in the host anti-tumor response. Our study is the first to report the association between polymorphisms in inflammation genes and HD susceptibility risk.

Rapid method for determination of DNA repair capacity in human peripheral blood lymphocytes amongst smokers.

BACKGROUND: DNA repair capacity is an important determinant of susceptibility to cancer. The hOGG1 enzyme is crucial for repairing the 8-oxoguanine lesion that occurs either as a byproduct of oxidative metabolism or as a result of exogenous sources such as exposure to cigarette smoke. It has been previously reported that smokers with low hOGG1 activity had significantly higher risk of developing lung cancer as compared to smokers with high hOGG1 activity. METHODS: In the current study we elucidate the association between plasma levels of 8-OHdG and the OGG1 repair capacity. We used the commercially available 8-OHdG ELISA (enzyme-linked immunosorbent assay), the Comet assay/FLARE hOGG1 (Fragment Length Analysis by Repair Enzymes) assay for quantification of the levels of 8-OHdG and measured the constitutive, induced and unrepaired residual damage, respectively. We compared the DNA repair capacity in peripheral blood lymphocytes following H2O2 exposure in 30 lung cancer patients, 30 non-, 30 former and 30 current smoker controls matched by age and gender. RESULTS: Our results show that lung cancer cases and current smoker controls have similar levels of 8-OHdG lesions that are significantly higher compared to the non-smokers controls. However, lung cancer cases showed significantly poorer repair capacity compared to all controls tested, including the current smokers controls. After adjustment for age, gender and family history of smoking-related cancer using linear regression, we observed a 5-fold increase in risk of lung cancer associated with high levels of residual damage/reduced repair capacity. Reduced OGG1 activity could be expected to be a risk factor in other smoking-related cancers. CONCLUSION: Our study shows that the Comet/FLARE assay is a relatively rapid and useful method for determination of DNA repair capacity. Using this assay we could identify individuals with high levels of residual damage and hence poor repair capacity who would be good candidates for intensive follow-up and screening.

Modulation of Radiation-Induced Genetic Damage by HCMV in Peripheral Blood Lymphocytes from a Brain Tumor Case-Control Study.

Human cytomegalovirus (HCMV) infection occurs early in life and viral persistence remains through life. An association between HCMV infection and malignant gliomas has been reported, suggesting that HCMV may play a role in glioma pathogenesis and could facilitate an accrual of genotoxic damage in the presence of g-radiation; an established risk factor for gliomas. We tested the hypothesis that HCMV infection modifies the sensitivity of cells to γ-radiation-induced genetic damage. We used peripheral blood lymphocytes (PBLs) from 110 glioma patients and 100 controls to measure the level of chromosome damage and cell death. We evaluated baseline, HCMV-, γ-radiation and HCMV + γ-radiation induced genetic instability with the comprehensive Cytokinesis-Blocked Micronucleus Cytome (CBMN-CYT). HCMV, similar to radiation, induced a significant increase in aberration frequency among cases and controls. PBLs infected with HCMV prior to challenge with γ-radiation led to a significant increase in aberrations as compared to baseline, γ-radiation and HCMV alone. With regards to apoptosis, glioma cases showed a lower percentage of induction following in vitro exposure to γ-radiation and HCMV infection as compared to controls. This strongly suggests that, HCMV infection enhances the sensitivity of PBLs to γ-radiation-induced genetic damage possibly through an increase in chromosome damage and decrease in apoptosis.

Genetic polymorphisms in DNA repair genes as modulators of Hodgkin disease risk.

BACKGROUND: Although the pathogenesis of Hodgkin disease (HD) remains unknown, the results of epidemiologic studies suggest that heritable factors are important in terms of susceptibility. Polymorphisms in DNA repair genes may contribute to individual susceptibility for development of different cancers. However, to the authors' knowledge, few studies to date have investigated the role of such polymorphisms as risk factors for development of HD. METHODS: The authors evaluated the relation between polymorphisms in 3 nucleotide excision repair pathway genes (XPD [Lys751Gln], XPC [Lys939Gln], and XPG [Asp1104His]), the base excision repair XRCC1 (Arg399Gln), and double-strand break repair XRCC3 (Thr241Met) in a population of 200 HD cases and 220 matched controls. Variants were investigated independently and in combination; odd ratios (OR) were calculated. RESULTS: A positive association was found for XRCC1 gene polymorphism Arg399Gln (OR, 1.77; 95% confidence interval [95% CI], 1.16-2.71) and risk of HD. The combined analysis demonstrated that XRCC1/XRCC3 and XRCC1/XPC polymorphisms were associated with a significant increase in HD risk. XRCC1 Arg/Arg and XRCC3 Thr/Met genotypes combined were associated with an OR of 2.38 (95% CI, 1.24-4.55). The XRCC1 Arg/Gln and XRCC3 Thr/Thr, Thr/Met, and Met/Met genotypes had ORs of 1.88 (95% CI, 1.02-4.10), 1.97 (95% CI, 1.05-3.73), and 4.13 (95% CI, 1.50-11.33), respectively. XRCC1 Gln/Gln and XRCC3 Thr/Thr variant led to a significant increase in risk, with ORs of 3.00 (95% CI, 1.15-7.80). Similarly, XRCC1 Arg/Gln together with XPC Lys/Lys was found to significantly increase the risk of HD (OR, 2.14; 95% CI, 1.09-4.23). CONCLUSIONS: These data suggest that genetic polymorphisms in DNA repair genes may modify the risk of HD, especially when interactions between the pathways are considered.

[Cytotoxicity and genotoxicity of human cells exposed in vitro to glyphosate]. / Citotoxicidad y genotoxicidad en células humanas expuestas in vitro a glifosato.

INTRODUCTION: Glyphosate is a broad-spectrum non-selective herbicide, used to eliminate unwanted weeds in agricultural and forest settings. Herbicide action is achieved through inhibition of aromatic amino acid biosynthesis in plant cells. Since this is not a conserved mechanism between human and plant cells, glyphosate is considered to be a low health risk substance for humans. However, the occurrence of possible harmful side effects of glyphosate use is not well documented and controversial. Toxicity and genotoxicity studies indicate that glyphosate is not harmful, although several investigations suggest that it can alter various cellular processes in animals. Therfore this has potential as a health and environmental risk factor in areas where glyphosate is widely used. OBJECTIVES: The present study evaluated glyphosate cytotoxic and genotoxic effects in normal human cells (GM38) and human fibrosarcoma (HT1080) cells. MATERIALS AND METHODS: Acute and chronic cytotoxicity were determined through the exposure of cultured cells to graded concentrations of glyphosate, and cell viability analysis was performed with crystal violet and Trypan blue staining. Genotoxicity was determined using the comet assay and data significance was evaluated with Dunnet's test. RESULTS: For chronic cytotoxicity a dose-dependent effect was observed in both GM38 and HT1080 cells after treatment with 5.2-8.5 mM and 0.9-3.0 mM glyphosate, respectively. In the acute cytotoxicity study, GM38 cells exposed to 4.0-7.0 mM glyphosate and HT1080 cells exposed to 4.5-5.8 mM glyphosate, had cell viability counts higher than 80%. Genotoxic effects were evidenced in GM38 cells at glyphosate concentrations of 4.0-6.5 mM and in HT1080 cells at glyphosate concentrations of 4.75 -5.75 mM. CONCLUSIONS: The levels of cytotoxicity and genotoxicity of glyphosate occurring in mammalian cells suggested that its mechanism of action is not limited to plant cells.

Citotoxicidad y genotoxicidad en células humanas expuestas in vitro a glifosato / Cytotoxicity and genotoxicity of human cells exposed in vitro to glyphosate

Introducción. El glifosato es un herbicida de amplio espectro, no selectivo, utilizado para eliminar malezas indeseables en ambientes agrícolas y forestales. La acción herbicida corresponde a la inhibición de la biosíntesis de aminoácidos aromáticos en las plantas. Al no ser este mecanismo compartido por los seres humanos es considerado como de bajo riesgo para la salud de los mismos. Sin embargo, investigaciones recientes indican que puede alterar otros procesos celulares en animales lo que puede presentar un factor de riesgo a nivel ambiental y de salud en las zonas donde se emplea este herbicida. Objetivo. El objetivo del presente estudio fue evaluar la citotoxicidad y la genotoxicidad del glifosato en células humanas normales (GM38) y en células humanas de fibrosarcoma (HT1080). Materiales y métodos. La citotoxicidad aguda y crónica se determinó al exponer las células en cultivo a diferentes concentraciones de glifosato, y se analizó la viabilidad celular con cristal violeta y colorante de exclusión azul de tripano, respectivamente. La genotoxicidad se determinó por medio del ensayo del cometa y los datos se analizaron usando la prueba de Dunnet. Resultados. En la citotoxicidad crónica las células GM38 y las HT1080 presentaron un efecto dependiente de la dosis después del tratamiento con glifosato en concentraciones de 5,2 a 8,5 mM y 0,9 a 3,0 mM, respectivamente. En la citotoxicidad aguda, las células GM38 y las HT1080 expuestas a un rango de concentraciones de 4,0 a 7,0 mM, 4,5 a 5,75 mM y 4,0 a 7,0 mM, respectivamente, presentaron una viabilidad mayor al 80 por ciento. Se evidenció daño en el ADN después del tratamiento con glifosato en concentraciones de 4,0 a 6,5 mM para las células GM38 y de 4,75 a 5,75 mM para las células HT1080. Conclusiones. Se sugiere que el mecanismo de acción del glifosato no se limita únicamente a las plantas sino que puede alterar la estructura del ADN en otros tipos de células como son las de los mamíferos