Number Of Micronuclei Research Articles

THE EFFECT OF PANORAMIC RADIOGRAPHY ON THE NUMBER OF MICRONUCLUES IN PERIODONTITIS

Background: Periodontitis is a periodontal disease that can cause an increase in Reactive Oxygen Species (ROS). The increase in ROS concentration will cause oxidative stress which has a role in DNA damage. In the case of periodontitis, panoramic radiography plays an important role in showing generalized horizontal bone loss. Radiation on panoramic radiography may cause DNA damage. DNA damage that occurs due to periodontitis or panoramic radiographic radiation exposure is characterized by the formation of micronuclei in gingival epithelial cells. Objective: To determine the effect of panoramic radiography on the number of micronuclei in Wistar rats with periodontitis. Method: This study was true experimental with post-test only and control group design. This study used 15 male Wistar rats which divided into 5 groups. Result: The average number of micronuclei in the normal group and 1 time exposures was 4 compared to the periodontitis group without exposure was 1.67, periodontitis and 1 time exposures was 8, periodontitis and 2 times the exposure was 15.67, and in the periodontitis and 3 times the exposure was 42.67. Result of One-Way Annova test and Post Hoc Bonferroni test indicated that signigicant changes in the number of micronuclei was seen between the normal group with 1 time exposure to the periodontitis group with 2 times and 3 times exposure and int the periodontitis group without exposure to the periodontitis group with 2 times and 3 times exposure. Conclusion: Panoramic radiograph X ray radiation and periodontitis can cause changes in the number of micronuclei in wistar rats. Keywords: , Micronucleus, Panoramic Radiography, Periodontitis.

Potential use of distinct biomarkers (trace metals, micronuclei, and nuclear abnormalities) in a heterogeneous sample of birds in southern Brazil.

The analysis of metal concentrations in bird feathers and genotoxicity tests are tools used to evaluate anthropogenic impacts on ecosystems. We investigated the response of birds, used as bioindicators, to disturbances observed in three areas with distinctive environmental characteristics (natural, agricultural, and urban) in southern Brazil. For this purpose, we quantified metals (Mn, Cu, Cr, and Zn) in feathers and determined the number of micronuclei (MN) and other nuclear abnormalities (NA) in 108 birds from 25 species and 17 families captured in the study area. No significant differences was found in the metal concentrations and the number of MN and NA between the sampling areas. Zn and Cu concentrations were significantly higher in insectivorous than those in omnivorous birds. The Zn concentration was significantly different between some species, and the Cu concentration was significantly higher in juveniles than that in adults. The best generalized linear models showed that omnivorous birds had more MN and NA and that juveniles and birds with better body condition index had increased NA numbers. This study demonstrates that the analyzed variables contribute in different ways to the result of each biomarker, mainly due to particular ecological and physiological characteristics of each species. We conclude that wild birds have the potential to be used as environmental bioindicators in the study area, but future studies should focus on one or a few species whose ecological and physiological habits are well known.

Genotoxicity of advanced glycation end products in vitro is influenced by their preparation temperature, purification and cell exposure time.

Advanced glycation end products (AGEs) are formed via non-enzymatic reactions between amino groups of proteins and the carbonyl groups of reducing sugars. Previous studies have shown that highly glycated albumin prepared using a glucose-bovine serum albumin (Glu-BSA) model system incubated at 60°C for 6 weeks induces genotoxicity in WIL2-NS cells at 9 days of exposure measured by the cytokinesis-block micronucleus cytome (CBMNcyt) assay. However, this AGE model system is not physiologically relevant as normal body temperature is 37°C and the degree of glycation may exceed the extent of albumin modification in vivo. We hypothesised that the incubation temperature and purification method used in these studies may cause changes to the chemical profile of the glycated albumin and may influence the extent of genotoxicity observed at 3, 6 and 9 days of exposure. We prepared AGEs generated using Glu-BSA model systems incubated at 60°C or 37°C purified using trichloroacetic acid (TCA) precipitation or ultrafiltration (UF) and compared their chemical profile (glycation, oxidation, and aggregation) and genotoxicity in WIL2-NS cells using the CBMNcyt assay after 3, 6 and 9 days of exposure. The number of micronuclei (MNi) was significantly higher for cells treated with Glu-BSA incubated at 60°C and purified via TCA (12 ± 1 MNi/1000 binucleated cells) compared to Glu-BSA incubated at 37°C and purified using UF (6 ± 1 MNi/1000 binucleated cells) after 9 days (P < 0.0001). The increase in genotoxicity observed could be explained by a higher level of protein glycation, oxidation, and aggregation of the Glu-BSA model system incubated at 60°C relative to 37°C. This study highlighted that the incubation temperature, purification method and cell exposure time are important variables to consider when generating AGEs in vitro and will enable future studies to better reflect in vivo situations of albumin glycation.

Colchicum Ritchii flower: a new molluscicidal plant for Biomphalaria alexandrina snails and the infective stages of Schistosoma mansoni

ABSTRACT Schistosomiasis is considered a neglected disease, but it is the cause of many social and economic problems in many developing countries. The aim of the present study was to find an alternative molluscicide of botanical origin to decrease the spread of this disease. The investigation studied the effect of the methanolic extract of Colchicum ritchii flowers on Biomphalaria alexandrina snails, larvae of Schistosoma mansoni, and the freshwater cladoceran Daphnia magna. The preliminary phytochemical screening test confirmed the presence of tannins and saponins that might be responsible for cytotoxic effects. The methanolic extract had a molluscicidal activity on B. alexandrina snails with an LC50 of 35.1 mg L−1 after 24 h of exposure. The LC50 of D. magna after 24 h was 63.5 mg L−1. The extract also had a larvicidal activity and caused alterations in the haemocytes of B. alexandrina snails. Aggregations of both hyalinocytes and granulocytes were formed after exposure for 24 h to LC25. Both the mean number of micronuclei per slide and the olive tail moment of snails exposed to LC10 and LC25 of the extract were increased compared to control snails. In conclusion, C. ritchii extract potentially could be used as a molluscicide and larvicide.

Evaluation of Radiosensitive Effect of Tolmetin in Radiotherapy on Human Colonic Carcinoma Cell Line HT-29

Background: Radiotherapy is one of the cancer treatment methods. Although radioresistance and normal tissue toxicity limit the radiation therapy in certain anatomical locations, using some substances can be useful to increase radiosensitivity on cancer cells without cytotoxicity effect on normal cells. Objective: This study aimed to evaluate the radiosensitizing effect of tolmetin in radiotherapy treatment on human colon cancer cell line HT-29. Methods In this study, human colon cancer cells HT-29 in different groups were irradiated with 4 Gy x-ray, and tolmetin was administered in different concentrations (75, 100, and 150 μM). Then, the groups were compared with each other and with the control group by Micronucleus Assay (MN) and Nuclear Division Index (NDI). NDI investigated the cytotoxicity, and MN indicated the genotoxicity. Results: In the group receiving radiation, micronuclei increased significantly compared to the control group. In the group receiving tolmetin with a concentration of 75 and 100 μM, the number of micronuclei also increased compared to the control group. In all groups treated with tolmetin that also received radiation, a significant increase in micronuclei was observed, which was more noticeable at concentrations of 100 and 150 μM. At the same time, tolmetin at the studied concentrations did not change the NDI index. Conclusion: The present study demonstrates that tolmetin has a radiosensitizing effect on HT-29 colon cancer cells, which depends on the tolmetin concentration. In addition, tolmetin has no cytotoxic effect on this cell line.

Bats are an excellent sentinel model for the detection of genotoxic agents. Study in a Colombian Caribbean region

Wildlife animals have been affected by human activities and the diminution of the areas needed to develop wildlife. In Colombia, artisanal and industrial mining focuses on gold extraction, which uses mercury and causes contamination in water sources. Bats may be susceptible to chemical contamination and primarily to bioaccumulated heavy metal contaminants in the food chain. The primary source of exposure is contaminated food and water ingest, followed by dermic exposition and inhalation. The objective was to evaluategenotoxic damage and mercury concentration in bats. Forty-five samples of blood and organs of bats captured in Ayapel and Majagual were collected. Erythrocytes were searched for micronuclei by peripheral blood smear. Mercury concentration in 45 liver and spleen samples was determined by atomic absorption spectroscopy (DMA80 TRICELL, Milestone Inc, Italy). Bats from four families were studied: Phyllostomidae (6 species), Molossidae (3 species), Vespertilionidae (1 species), and Emballonuridae (1 species). Mercury was found in all bat species from the different dietary guilds. Insectivores had the highest concentration of mercury in the liver (0,23 µg/g) and spleen (0,25 µg/g) and the highest number of micronuclei (260 micronuclei/10,000). The specimens captured in Majagual had the highest frequency of micronuclei (677 micronuclei/10,000), and those captured in Ayapel had the highest mercury concentration (0,833 µg/g). This is the first study in Colombia to report that bats could act as sentinels to the environment's genotoxic chemical agents. Mercury and a high frequency of micronuclei were found in the tissues of captured bats. In addition to mercury contamination, there could also be other contaminants affecting Chiroptera.

Quantitative assessment of micronuclei in oral exfoliative buccal squamous cells in smokers, chewers and healthy individuals using Giemsa Stain and Papainicolous Stain

Context: The main reason for oral cancer is tobacco consumption in various forms, such as chewing and smoking. Micronuclei in oral exfoliated cells are markers of chromosomal damage caused by toxic genetic agents from tobacco-related substances, alcohol, etc. The number of micronuclei indicates the cell's genotoxic effect and can be used as a biomarker to assess the changes in the cellular changes. Recently research is focused on determining early genotoxicity changes using exfoliative cytology in human buccal epithelial cells. Aim: Quantitative analysis of micronuclei in oral exfoliated oral, buccal mucosal cells using Papainicolous stain with Giemsa stain in tobacco users in the form of chewing and smoking in comparison with healthy individuals. Materials and methods: A total of seventy-five cases were selected for this study. Among seventy-five participants divided into three groups based on habits tobacco smokers (n=25), tobacco chewers (n=25), and healthy individuals (n=25). Results: The mean number of micronuclei in Giemsa stain was 255.2 ± 78 compared with PAP stain155.12 ± 78.5. The increased mean number of micronuclei in chewers 273.24 ± 80.7, and different stain comparison Giemsa stain showed highest in chewers. A mean number of micronuclei showed statistically highly significant (p≤0.05). Pair-wise comparison of micronuclei inter and intra groups in all three groups, smokers and chewers showed highly statistically substantial (p≤ 0.0001) compared with healthy individuals. Conclusion: Micronuclei provide evidence that consumption of smokeless tobacco may be developing oral cancer, and micronuclei assay can be used as biomarkers of genotoxicity and carcinogenesis progression. Key word: Cytological smear, Genotoxicity, Micronuclei, Oral cancer, Tobacco chewers

In vivo genotoxic and cytotoxic evaluation of venom obtained from the species of the snake ophryacus, cope, viperidae

The present study was made to determine the mouse in vivo micronuclei induction capacity of the venom obtained from three Mexican endemic snakes: Ophryacus undulatus, Ophryacus smaragdinus, and Ophryacus sphenophrys. A second aim was to determine their capacity to induce bone marrow cytotoxicity in the same animals. Results obtained in mouse peripheral blood showed that O. undulatus venom moderately increased the number of micronuclei and produced cytotoxic damage. The venom of O. smaragdinus was also a moderate micronuclei and cytotoxic inducer, and the venom of O. sphenophrys showed neither genotoxic nor cytotoxic effect.

A MATLAB-based program for three-dimensional quantitative analysis of micronuclei reveals that neuroinflammation induces micronuclei formation in the brain

The micronucleus is known to be a biomarker for genomic instability, which is a hallmark of tumors and aging. Normally, micronuclei are produced by segregation errors and mechanical stresses arising from dividing or migrating cells, leading to activation of the innate immune response pathway. Although micronuclei often emerge in damaged tissues, the quantitative procedure for analyzing micronuclei accurately has been problematic. Here, we introduce a novel MATLAB-based program for quantifying micronuclei (CAMDi: calculating automatic micronuclei distinction) in vitro and in vivo. CAMDi is adaptable to various experimental imaging techniques and is useful for obtaining reproducible data. CAMDi enables us to measure the accurate size of micronuclei from the three-dimensional images. Using CAMDi, we revealed a novel link between the emergence of micronuclei and neuroinflammation. We found that inflammatory stimulation does not increase the number of micronuclei in primary neurons. On the other hand, the administration of lipopolysaccharide into mice slightly increases micronuclei formation in neurons of the hippocampus region. These findings demonstrate that neuronal micronuclei formations are induced by an inflammatory response in a non-cell-autonomous manner. We provide a novel tool, CAMDi, to quantify micronuclei and demonstrate that neuronal micronuclei are produced not only by the cell-autonomous process but also by the intercellular communication associated with neuroinflammation in vivo.

The role of dosimetry and biological effects in metastatic castration\u2013resistant prostate cancer (mCRPC) patients treated with 223Ra: first in human study

Background223Ra is currently used for treatment of metastatic castration resistant prostate cancer patients (mCRPC) bone metastases with fixed standard activity. Individualized treatments, based on adsorbed dose (AD) in target and non-target tissue, are absolutely needed to optimize efficacy while reducing toxicity of α-emitter targeted therapy. This is a pilot first in human clinical trial aimed to correlate dosimetry, clinical response and biological side effects to personalize 223Ra treatment.MethodsOut of 20 mCRPC patients who underwent standard 223Ra treatment and dosimetry, in a subset of 5 patients the AD to target and non-target tissues was correlated with clinical effects and radiation-induced chromosome damages. Before each 223Ra administrations, haematological parameters, PSA and ALP values were evaluated. Additional blood samples were obtained baseline (T0), at 7 days (T7), 30 days (T30) and 180 days (T180) to evaluate chromosome damage. After administration WB planar 223Ra images were obtained at 2–4 and 18–24 h. Treatment response and toxicity were monitored with clinical evaluation, bone scan, 18F-choline-PET/CT, PSA value and ALP while haematological parameters were evaluated weekly after 223Ra injection and 2 months after last cycle.Results1. a correlation between AD to target and clinical response was evidenced with threshold of 20 Gy as a cut-off to obtain tumor control; 2. the AD to red marrow was lower than 2 Gy in all the patients with no apparently correlation between dosimetry and clinical toxicity. 3. a high dose dependent increase of the number of dicentrics and micronuclei during the course of 223Ra therapy was observed and a linear correlation has been found between blood AD (BAD) and number of dicentrics.ConclusionsThis study provides some interesting preliminary evidence to be further investigated: dosimetry may be useful to identify a more appropriate 223Ra administered activity predicting AD to target tissue; a dose dependent complex chromosome damage occurs during 223Ra administration and this injury is more evident in heavily pre-treated patients; dosimetry could be used for radioprotection purpose.Trial registrationThe pilot study has been approved from the Ethics Committee of Regina Elena National Cancer Institute (N:RS1083/18–2111).

Evaluation of the Role of Vitamin C and Melatonin on the Genetic Disorder of Human Blood Lymphocytes in the Presence of Vincristine and Permethrin

Introduction: Various studies have shown that vincristine and permethrin have genetic toxicity on the body's normal cells. Due to the widespread use of these drugs, preventing their toxicity is essential; therefore, in this study, the protective effects of vitamin C and melatonin on the genetic toxicity induced by vincristine and permethrin in peripheral blood lymphocytes were investigated.&#x0D; Material and Methods: The protective effects of vitamin C and melatonin (doses of 50, 100 and 200 µm) on the toxicity of vincristine and permethrin induced by micronucleus test on peripheral blood lymphocytes were evaluated ,and in statistical tests P &lt;0.05 as the significant level was considered.&#x0D; Results: According to the results vincristine and permethrin caused genetic disorder by 28.80 ± 1.92 and 34±1.58 micronucleus respectively (p&lt;0.0001). However, by exposing vitamin c and melatonin with permethrin at concentrations of 100 μM and 200 μM, the number of micronuclei was significantly decreased by 24.80 ±2.91, 18.00±1.58 (Vit C) and 22.20±3.34, 15.40±1.14 (melatonin) respectively. In contrast, exposure of these two substances together with vincristine in similar concentrations reduced the micronucleus by 16.60± 2.07 ,10.80± 0.83 (Vit C) and 13.00± 1.58, 6.40± 1.14 (melatonin) respectively.&#x0D; Conclusion: As the results of this study showed, permethrin and vincristine both caused genetic toxicity. Melatonin can protect against DNA damage by purifying reactive oxygen species or stimulating the DNA repair system. Vitamin C plays an essential protective role in many toxic reactions of the body. Both antioxidants have been shown to reduce the genetic toxicity of permethrin and vincristine.

The effect of X-ray irradiation to the formation of polychromatic erythrocyte cell micronucleus in Wistar rats (Rattus norvegicus)

Background: Panoramic and cephalometric radiography is very important for diagnosis, treatment plan, and evaluation of orthodontic treatment results. Panoramic and cephalometric radiography are frequently performed at the same time, causing DNA damage and chromosome aberration. Purpose: This study aims to analyse the effect of X-ray exposure in panoramic and cephalometric radiography on micronuclei cell numbers. Methods: Laboratory-based analytical study with 60 healthy-male Wistar rats weighing 200–300 grams divided into 6 treatment groups (n=10). The control group: without radiographic exposure, the treatment group 2: using panoramic radiographic exposure followed by cephalometric, and the treatment group 3: using panoramic radiographic exposure and 24 hours later performed cephalometric radiographic. The unit of analysis was the polychromatic erythrocytes of mice cell, were examined 24 hours and 48 hours after irradiation had been finished. The polychromatic erythrocytes were examined using May-Gruenwald-Giemsa staining and 100x magnification under a microscope with 2000 cells per view. Data obtained were analysed using the SPSS 20 version software. The mean and standard deviations were calculated for each clinical parameter, and a one‐way ANOVA statistical test of significance was used. Statistical significance was set at p&lt;0.05. Results: The analysis showed a significant increase (p&lt;0.05) in the number of micronucleus in groups that used panoramic radiographic exposure followed by cephalometric. Conclusion: X-ray radiation can increase the number of micronucleus in polychromatic erythrocyte cells in rats.

Hesperidin prevents the combined toxicity of decabromodiphenyl ether and sodium nitrite in vitro

Decabromodiphenyl ether (BDE-209) and Sodium nitrite (SN) coexist in the processing meat and fish foods, but there is no research considering them together. The present study aimed to investigate the binary mixture's toxicity of BDE-209 and SN and explore the protective effect of hesperidin (Hsp) on the combined toxicity. Results showed that compared with the impact of BDE-209 or SN alone, the binary mixture had a synergistic toxic effect on impairing the viability of HepG2 cells, accompanied by oxidative stress, Ca2+ accumulation, mitochondrial dysfunction. The increase of γ-H2AX fluorescent foci and micronuclei number also indicated its genotoxicity. Pretreatment of Hsp could significantly alleviate the above damage caused by the binary combination. These findings revealed the toxicological interaction of BDE-209 and SN and highlighted that food containing abundant natural flavonoids, as hesperidin, could reduce this toxicological risk.

Assessment of Unstimulated Whole Salivary Tumor Necrosis Factor Alpha (TNF-α) and Cellular Micronuclei Levels in Snuff (Naswar) Users and Non-Users for Early Diagnosis of Oral Squamous Cell Carcinoma.

The aim of the study was to investigate the unstimulated whole saliva (UWS) tumor necrosis factor alpha (TNF-α) and cellular micronuclei in snuff dippers (Naswar) compared to healthy control subjects. The case control study was conducted over 9 months at a tertiary care center. Sixty patients were divided into two groups: Snuff dippers (SD) (Naswar) and non-snuff dippers (NSD) (control subjects). The included self-reported SD used Snuff twice daily for more than 12 months. UWS was collected and salivary TNF-α assessment was performed using enzyme-linked immunosorbent assay (ELISA). For cellular micronuclei, buccal mucosa was brushed to obtain cells in Naswar users, fixed with a dibutylphthalate polystyrene xylene (DPX) mounting to view micronuclei. Means and standard deviations were compared using the t-test and outcomes were related using Pearson correlation, considering p ≤ 0.05 as significant. The mean age of participants was 38.85 ± 11.56 years. The mean duration of snuff use was 20.43 ± 12.79 years and the common site for Naswar placement was the lower vestibule (n = 19, 63.3%). TNF-α levels among SD were 9.6 ± 3.3 pg/mL, which were significantly higher than levels in NSD, 5.2 ± 3 pg/mL (p < 0.05). The number of cellular micronuclei in SD was 30.7 ± 7.8, which was comparatively higher than in NSD, which was 9.2 ± 3.3 (p < 0.05). The duration of snuff use was positively correlated to TNF-α levels (p = 0.048) rather than the micronuclei number (p = 0.97). SD showed higher levels of TNF-α and cellular micronuclei compared with NSD (control subjects); a positive correlation was shown with the duration of snuff use. We conclude that TNF-α and micronuclei are potential salivary biomarkers for an oral biological effect in snuff (Naswar) users.

Depletion of DNA Polymerase Theta Inhibits Tumor Growth and Promotes Genome Instability through the cGAS-STING-ISG Pathway in Esophageal Squamous Cell Carcinoma.

Simple SummaryDNA polymerase theta, encoded by the human POLQ gene, is upregulated in several cancers and is associated with poor clinical outcomes. The importance of POLQ, however, has yet to be elucidated in esophageal cancer. In this study, we explored the functional impacts of POLQ and looked into its underlying mechanisms. POLQ was overexpressed in esophageal squamous cell carcinoma (ESCC) tumors associated with unfavorable prognosis and contributed to malignant phenotypes by promoting genome stability, suggesting that targeting polymerase theta may provide a potential therapeutic approach for improving ESCC management.Overexpression of the specialized DNA polymerase theta (POLQ) is frequent in breast, colon and lung cancers and has been correlated with unfavorable clinical outcomes. Here, we aimed to determine the importance and functional role of POLQ in esophageal squamous cell carcinoma (ESCC). Integrated analysis of four RNA-seq datasets showed POLQ was predominantly upregulated in ESCC tumors. High expression of POLQ was also observed in a cohort of 25 Hong Kong ESCC patients and negatively correlated with ESCC patient survival. POLQ knockout (KO) ESCC cells were sensitized to multiple genotoxic agents. Both rH2AX foci staining and the comet assay indicated a higher level of genomic instability in POLQ-depleted cells. Double KO of POLQ and FANCD2, known to promote POLQ recruitment at sites of damage, significantly impaired cell proliferation both in vitro and in vivo, as compared to either single POLQ or FANCD2 KOs. A significantly increased number of micronuclei was observed in POLQ and/or FANCD2 KO ESCC cells. Loss of POLQ and/or FANCD2 also resulted in the activation of cGAS and upregulation of interferon-stimulated genes (ISGs). Our results suggest that high abundance of POLQ in ESCC contributes to the malignant phenotype through genome instability and activation of the cGAS pathway.

Immune Microenvironment Contributes to Dysregulation of Aid/Apobec Expression and Genomic Instability in Multiple Myeloma

Multiple myeloma (MM) is a plasma cell malignancy with marked genomic instability. Using whole genome sequencing, we have previously demonstrated that myeloma cells display heterogeneity in mutational spectrum and diverse patterns of clonal evolution. We have also identified AID/APOBEC-driven signature as one of 2 biologically distinct mutational signatures responsible for the majority of observed mutations. Our data show that several members of APOBEC family (including 3A, B, C, and G) are up regulated in patient MM cells and cell lines. Using SNP array and whole genome sequencing, we have also confirmed that elevated expression of APOBECs (3B, C, and G) contributes to genomic instability in MM cells. Since genomic instability and associated clonal evolution could also be driven by pressures from microenvironment, in this study we investigated the role of microenvironment in dysregulation of AID/APOBECs in MM cells.In normal cellular environment, AID and APOBECs are expressed by B and T cells and play a key role in adaptive and innate immunity. However, their expression is tightly regulated in order to prevent nonspecific damage to cellular DNA. We hypothesized that abnormal immune components and soluble factors in the bone marrow microenvironment can induce APOBEC expression in MM cells and can contribute to genomic instability. As we have previously shown that pDCs, MDSCs, Th17cells and B1/B2 cell ratio were significantly elevated in peripheral blood and bone marrow of MM patients, we evaluated the role of these immune cells (iDC, pDC, B, B1, and T cells), and soluble components (IL6, IL-17, IL-27, IFNa, and IFNb) on APOBEC expression and activity in myeloma cells. We used purified immune cells from healthy donors and co-cultured them with MM cells. Following a 3 day co-culture, MM cells were purified and analyzed. APOBEC expression by RT-qPCR. Co-culture with immune cells caused increased expression (range: 2-100 fold) of several APOBEC family genes in myeloma cells. Among different immune cells, iDC and pDC induced the expression of AID, A3A, A3G, and A3H; TLR9 activated B cells induced the expression of AID and A3G; B1 cells induced expression of AID, A3A and A3G; and, IL-17 activated T cells induced the expression of AID, A3A and A3G. Among soluble components of immune microenvironment, interferon a and β induced APOBEC expression (A3A, A3G, and A3H; range: 4-15 fold) in myeloma cells after treatment. Interestingly, none of the interleukins tested showed any impact on APOBEC gene expression in these cells. We then tested if IRF9, a downstream effector of type-1 interferons is involved in the interferon-mediated induction of APOBECs. IRF9-siRNA significantly inhibited interferon-mediated induction of APOBECs (by 50%) in myeloma cells suggesting that interferon mediated up-regulation of APOBECs in MM cells is mediated at least in part by IRF9. We also used a functional assay and demonstrated that increased expression of APOBEC genes was associated with increased APOBEC deaminase activity in MM cells. To investigate the genomic impact of interferon induced APOBEC activity, we treated MM cells with IFN-β and evaluated its impact on abasic sites (that could directly result from APOBEC deaminase activity) and micronuclei assay (a marker of genomic instability). The number of abasic sites and micronuclei were increased by 2 and 4 fold respectively, in cells treated with IFN-β. Overall, these results suggest that BM microenvironment can induce APOBEC expression/activity and associated genomic instability in MM cells. DisclosuresNo relevant conflicts of interest to declare.

Cytotoxicity and genotoxicity of salicylate- and calcium silicate-based root canal sealers on primer human periodontal ligament fibroblasts.

The aim of this study was to evaluate the biocompatibility of epoxy-resin-based AHPlus, salicylate-based MTA-Fillapex and calcium silicate-based iRootSP root canal sealers. Cytotoxicity was assessed by XTT test. The extracts from sealers of different setting times were serially diluted. Cell viability was calculated as the percentage of the control group (100%). The optimal concentration of each sealer was used at genotoxicity test, and micronuclei formations were detected. Statistical analyses were done by using Kruskal-Wallis and Dunn post hoc test with Bonferroni correction. AHPlus and MTA-Fillapex showed the lowest percentage of cell viability at higher concentrations (1:1, 1:2, 1:4), especially at first 12 h. iRootSP showed higher viability at all concentrations and times than AHPlus and MTA-Fillapex. At genotoxicity assay, AHPlus increased the number of micronuclei. MTA-Fillapex slightly induced micronucleus formation (not significant) and iRootSP was not increased. In conclusion, calcium silicate-based iRootSP had lowest cytotoxic and genotoxic potential and can be considered as a highly biocompatible material.

Evaluation of Micronuclei and Cytomorphometric Changes in Patients with Different Tobacco Related Habits Using Exfoliated Buccal Cells.

Background:Tobacco is one of the main reasons behind the occurrence of oral cancer. Oral cancer, even though being the tenth most common cancer in the world, gets diagnosed at an advanced stage and ends up with poor prognosis. So early diagnosis is the need of the hour. Our study aimed to evaluate the genotoxic changes in patients with different tobacco habits using buccal exfoliated cells. Methods:Buccal smears were taken from smokers (30), smokeless tobacco users (30), combined tobacco users (30) and controls (30) with clinically normal oral mucosa. All the smears were stained with Papanicolaou stain and Feulgen stain and viewed under light microscope for the evaluation of mean number of micronuclei, mean micronuclei per cell, frequency of cells showing micronuclei, nuclear area, cytoplasmic area, nuclear-cytoplasmic ratio. Results:Mean number of micronuclei, mean micronuclei per cell, frequency of cells showing micronuclei, and nuclear area were significantly increased in tobacco users than controls, especially in combined tobacco users. Nuclear-cytoplasmic ratio was increased and cytoplasmic area was decreased in tobacco users than controls. Conclusion:Tobacco in any consumable form is genotoxic. Smoking and smokeless tobacco, when consumed together, synergistically causes higher genetic damage. Different tobacco habits have different deleterious effects on oral mucosa, and these effects are more pronounced when the patients have combined habits. So, detecting the genotoxic changes through exfoliative cytology can be used as a simple yet reliable marker for early detection of carcinogenesis.

The Genotoxic and Pro-Apoptotic Activities of Advanced Glycation End-Products (MAGE) Measured with Micronuclei Assay Are Inhibited by Their Low Molecular Mass Counterparts.

An association between the cancer invasive activities of cells and their exposure to advanced glycation end-products (AGEs) was described early in some reports. An incubation of cells with BSA–AGE (bovine serum albumin–AGE), BSA–carboxymethyllysine and BSA–methylglyoxal (BSA–MG) resulted in a significant increase in DNA damage. We examined the genotoxic activity of new products synthesized under nonaqueous conditions. These were high molecular mass MAGEs (HMW–MAGEs) formed from protein and melibiose and low molecular mass MAGEs (LMW–MAGEs) obtained from the melibiose and N-α-acetyllysine and N-α-acetylarginine. We have observed by measuring of micronuclei in human lymphocytes in vitro that the studied HMW–MAGEs expressed the genotoxicity. The number of micronuclei (MN) in lymphocytes reached 40.22 ± 5.34 promille (MN/1000CBL), compared to 28.80 ± 6.50 MN/1000 CBL for the reference BSA–MG, whereas a control value was 20.66 ± 1.39 MN/1000CBL. However, the LMW–MAGE fractions did not induce micronuclei formation in the culture of lymphocytes and partially protected DNA against damage in the cells irradiated with X-ray. Human melanoma and all other studied cells, such as bronchial epithelial cells, lung cancer cells and colorectal cancer cells, are susceptible to the genotoxic effects of HMW–MAGEs. The LMW–MAGEs are not genotoxic, while they inhibit HMW–MAGE genotoxic activity. With regard to apoptosis, it is induced with the HMW–MAGE compounds, in the p53 independent way, whereas the low molecular mass product inhibits the apoptosis induction. Further investigations will potentially indicate beneficial apoptotic effect on cancer cells.

Investigation of genetic toxicity and oxidative stress of Clostridium perfringens epsilon toxin type D on human peripheral blood lymphocytes

Epsilon toxin (Etx) is an enormously potent pore-forming toxin and a category B biological agent. Etx is the main virulence determinant of Clostridiumperfringens types B and D toxin. It has a cytotoxic effect on distal and collecting kidney tubules. Also, Etx crosses the blood-brain barrier, binds to myelin structures, and destroys oligodendrocytes.The main purpose of this study was to investigate the toxic effects of Etx on human blood lymphocytes, which we examined for the first time for the genetic toxicity of this bacterial toxin. In this study, after taking blood and dividing into nine groups and putting in contact with different dilutions of Etx (1,5,10,25,50,100 and 200 μM), methotrexate (750 μM), and normal saline by Cytokinesis blocked micronucleus (CBMN) assay, we looked at genetic toxicity and the level of oxidative stress created in the under study lymphocytes.The results of this study showed that Etx has significant oxidative stress effects on human lymphocytes at doses above 25 μM, and also this bacterial toxin significantly increases the number of micronuclei formed in lymphocytes.The results of this study indicate that Etx has toxic effects it is genetic and interferes with cell division processes. Thus, human lymphocytes can be used extensively in future studies on Etx.