Micronucleus Research Articles

RAPID ON-SITE EVALUATION AND MICRONUCLEUS SCORING IN BREAST LESIONS FINE NEEDLE ASPIRATION CYTOPATHOLOGY BY NEW IAC YOKOHAMA SYSTEM OF REPORTING

Objective: The objective of the study is to report all fine needle aspiration cytopathology (FNAC) cases of lump breast as per New Yokohama classification 2016, to highlight the importance of rapid onsite evaluation (ROSE) in breast cytology at the time of FNAC, and to assess the relationship between micronucleus (MN) scoring and various breast lesions in cytology. Methods: The study was conducted on 70 patients with breast lumps in the Department of Pathology in Government Medical College, Patiala, and comprised evaluation of ROSE and MN scoring in breast FNAC by the use of New Yokohama system of reporting. Results: On ROSE, 11 out of 70 patients were categorized under category I according to the Yokohama system of reporting and on the same sitting with repeat FNAC after performing the ROSE; nine cases were upgraded for cytological reporting and two remained in category I. According to as per the International Academy of Cytology (IAC) Yokohama system of reporting (2016) cases were categorized as category I – 2 (2.9%), category II – 46 (65.7%), category III – 7 (10.1%), category IV – 5 (7.1%), and category V – 10 (14.2%). In MN scoring, MN with the highest score of 14–17/1000 epithelial cells was in category V (malignant), and the lowest score was 0–1/1000 epithelial cells in category II (benign). Conclusion: ROSE is an easy, safe, and cost-effective method. IAC Yokohama system for reporting (2016) provides a comprehensive way of categorizing various breast lesions on FNAC with clinical correlation. MN score is a good biomarker in differentiating benign, atypical, and malignant breast lesions.

Controlled dual activity of an organometallic antibiotic through micelle formulation

Sodium Lauryl Sulphate (SLS) and Cetyltrimethylammonium bromide (CTAB) were employed to create micelles (SLS@CIPTIN and CTAB@CIPTIN) of the organometallic antibiotic Ph2Sn(CIP)2 (CIPTIN) (where HCIP= ciprofloxacin). The characterization of the micelles was conducted in the solid-state using melting point, Attenuated Total Reflectance-Fourier Transform Infra-Red (ATR-FTIR), 119Sn Mössbauer and X-ray Fluorescence (XRF) spectroscopies, and Thermogravimetry/Differential Thermal Analysis (TG-DTA), while in solution, by Ultra violet-Visible (UV–Vis) and Nucleus Magnetic Resonance (1HNMR ) spectroscopic techniques were employed. The compounds were tested for their antiproliferative activity against human breast adenocarcinoma cells: MCF-7 (hormone depended (HD)) and MDA-MB-231 (hormone independent (HI)). The in vitro and in vivo non-genotoxicity was confirmed with micronucleus (MN) and Artemia salina assay. The antiproliferative mechanism of action of SLS@CIPTIN and CTAB@CIPTIN was studied by cell morphology and cell cycle arrest. The antibacterial activity was evaluated using Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Inhibition Zones (IZ) against Minimum Bactericidal Concentration (MBC) against Gram-negative strains P. aeruginosa, E. coli, as well as Gram-positive strains S. epidermidis and S. aureus. The results indicate that both the investigated CIPTIN and its supramolecular assembly (SLS@CIPTIN) exhibit activity. Therefore, the encapsulation of antimicrobial compounds can indeed be regarded as an attractive strategy for the development of new dual-active agents. These agents offer concurrent anticancer and antibacterial attributes without inducing toxicity.

Genotoxicity and Cytotoxicity Activities of Stembark Extract of Mammea africana

Mammea africana, a medicinal plant, used in ethnomedicine for the treatment of malaria, diabetes, poisoning and inflammatory diseases was investigated for cytotoxic and genotoxic effects on the root meristem cells of Allium cepa. Onion bulbs were exposed to 2.5 mg/mL, 5mg/mL, and 10 mg/mL concentrations of the stembark extract for macroscopic and microscopic analysis. Tap water was used as a negative control and Methotrexate (0.1 mg/mL) as a positive control. There was statistically significant (p< 0.05) inhibition of root growth depending on concentration by the extract when compared with the negative control group. All the tested concentrations of the extract were observed to have cytotoxic effect on cell division in A. cepa. When compared to the control group, the extract-induced chromosomal abnormalities and micronuclei (MNC) forms in A. cepa root tip cells were substantial (p<0.05). Further inducing cell death, ghost cells, membrane damage, and binucleated cells was the extract treatment. These findings imply that the phytochemical components of Mammea africana root extract exert their cytotoxic and genotoxic actions on A. cepa.

RebL1 is required for macronuclear structure stability and gametogenesis in Tetrahymena thermophila

Histone modification and nucleosome assembly play important roles in chromatin-related processes. Histone chaperones form different complexes and coordinate histone transportation and assembly. Various histone chaperone complexes have been identified in different organisms. The ciliate protozoa (ciliates) have various chromatin structures and different nuclear morphology. However, histone chaperone components and functions of different subunits remain unclear in ciliates. Tetrahymema thermophila contains a transcriptionally active macronucleus (MAC) and a transcriptionally inactive micronucleus (MIC) which exhibit multiple replication and various chromatin remodeling progresses during vegetative growth and sexual developmental stages. Here, we found histone chaperone RebL1 not only localized evenly in the transcriptionally active MAC but also dynamically changed in the MIC during vegetative growth and sexual developmental stages. REBL1 knockdown inhibited cellular proliferation. The macronuclear morphology became bigger in growing mutants. The abnormal macronuclear structure also occurred in the starvation stage. Furthermore, micronuclear meiosis was disturbed during sexual development, leading to a failure to generate new gametic nuclei. RebL1 potentially interacted with various factors involved in histone-modifying complexes and chromatin remodeling complexes in different developmental stages. REBL1 knockdown affected expression levels of the genes involved in chromatin organization and transcription. Taken together, RebL1 plays a vital role in maintaining macronuclear structure stability and gametogenesis in T. thermophila.

Effect of maternal diet on the frequency of micronuclei in pregnant women and newborns: A protocol for systematic review and meta-analysis.

The effects of diet on maternal and child genetic levels have been previously reported. Diet-associated DNA damage, such as the presence of micronuclei (MN), may be related to an increased risk of developing chronic diseases, such as cancer. Such damage is particularly concerning during pregnancy as it can affect the newborn. This review will aim to summarize the primary evidence of the impact of diet during pregnancy on micronucleus frequency in the maternal-newborn population. This protocol was developed based on the Preferred Reporting Items guidelines for Systematic Reviews and Meta-analyses Protocol. The review was registered with the International Register of Prospective Systematic Reviews on February 17, 2022 (registration number: CRD42022302401). We will use PubMed, Embase, Web of Science, Scopus, Science direct, and Google databases to search for observational studies. This review will include studies that investigate the diet consumed by pregnant women and its effect on the frequency of MN in mothers and newborns without any time or language limitations. For data extraction, researchers will independently review the full text and collect information that characterizes the study and its findings. We will analyze the results by calculating the odds ratio for each type of diet evaluated, accompanied by a 95% confidence interval. We will perform a quantitative synthesis of homogeneous studies to perform a meta-analysis. Micronucleus frequency quantifies the effect and will be presented as the mean and standard deviation or median and interquartile range. This review will aim to identify which dietary patterns during pregnancy may be associated with an increase in the frequency of MN in mothers and their newborns. Understanding the impact of diet on the frequency of MN is essential to deepen studies and to propose strategies that aim to protect the health of the public through food.

Exogenous application of mycotoxin fusaric acid improve the morphological, cytogenetic, biochemical and anatomical parameters in salt (NaCl) stressed Allium cepa L.

Salinity is one of the most important abiotic stress factors that negatively affect plant growth and development. In contrast, fusaric acid (FA), a mycotoxin produced by Fusarium and Giberella fungal genera, has biological and metabolic effects in various plants. In this study, it was aimed to investigate the protective effect of externally applied FA (0.1 nM) against the damage caused by salt (0.15 M NaCl) stress in onion (Allium cepa L.) plant. Salt stress resulted in an increase in the chromosomal aberrations (CAs) and micronucleus (MN) frequency, a decrease in the mitotic index (MI), fresh weight, root number, germination percentage, and root length. It promoted CAs such as irregular mitosis, bilobulated nuclei, chromosome loss, bridge, unequal seperation of chromosome, vagrant chromosome and polar slip in root meristem cells. In addition, salt stress caused a enhancement in free proline (PR), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) contents in the roots of onion plant. Moreover, it revealed damage and changes that include the accumulation of some chemical substances such as proline and sugars in epidermis and cortex layer cells, epidermal cell injury, flattening of the cell nucleus, wall thickening in cortex cells, necrotic areas and indistinct transmission tissue in the anatomical structure of onion roots. On the other hand, FA application promoted bulb germination and mitotic activity, strengthened the antioxidant defense system, and reduced chromosome and anatomical structure damages. In conclusion; it has been revealed that exogenous FA application may have a positive effect on increasing the resistance of onion plants to salt stress.

Abstract 1260: Collapse of cancer cell micronuclei from oxidative damage

Abstract Chromosomal instability, a hallmark of aggressive cancers, disrupts genome integrity through multiple hits by ongoing missegregation of chromosomes. These chromosomes, inherited only by one daughter cell, are subsequently encapsulated in micronuclei (MNi). Micronucleation is detrimental for replication fidelity not only because it sustains chromosomal missegregation, but also because MNi frequently undergo irreversible collapse during interphase exposing their enclosed chromatin to the cytosol. This exposure catalyzes chromosomal rearrangements and heritable epigenetic abnormalities that have been shown to further bolster cancer evolution and therapeutic resistance. Moreover, MNi collapse is known to promote distant metastasis and poor prognosis through eliciting a non-canonical response of otherwise inflammatory signaling pathways. Despite the fundamental role played by MNi catastrophe in compromising genome integrity and sustaining cancer progression, and the subsequent therapeutic potential of targeting this process, the mechanisms underlying MNi collapse are poorly understood. Here, we identify mitochondria-derived reactive oxygen species (ROS) as the main cause of MNi rupture. Notably, we observe that MNi that locate closer to mitochondria are more prone to rupture. Accordingly, increasing ROS chemically and by H2O2 addition increment rupture in a panel of 5 different tumor cell lines, while decreasing ROS using pan-cellular or mitochondrial specific scavengers reduce the frequency of ruptured MNi. By using a combination of advanced super-resolution microscopy, proteomics, transcriptomics, in vitro biochemistry assays, and extensive mutagenesis, we reveal the exact pathway leading to MNi collapse. We demonstrate that ROS promote a noncanonical function of the membrane repair ESCRT-III complex scaffolding protein, CHMP7. ROS reduce CHMP7 interaction with ESCRT-III promoting CHMP7 oligomerization and its binding to the inner nuclear membrane protein, LEMD2. CHMP7, while aggregating, physically pulls the micronuclear envelope together with the LEMD2-associated lamina, thereby disrupting MNi integrity. Finally, we show that hypoxic conditions promote ROS-dependent CHMP7-LEMD2 interaction, inducing MNi rupture and inflammatory signaling. Thus, we observe that human tumors characterized by hypoxia have a significantly increased predominance of ruptured MNi, providing a mechanistic link between tumor hypoxia and downstream processes that drive cancer progression. Citation Format: Melody Di Bona, Yanyang Chen, Albert Agustinus, Matthew Deyell, Mercedes A. Duran, Christy Hong, James Hickling, Daniel Bronder, Sara Martin, Nadeem Riaz, Bill Diplas, Manisha Jalan, Nancy Lee, Alban Ordureau, Benjamin Izar, Ashley Laughney, Simon Powell, Stefano Santaguida, John Maciejowski, Thomas Jeitner, Samuel Bakhoum. Collapse of cancer cell micronuclei from oxidative damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1260.

Abstract 4400: Transcriptional dysregulation of chromosomes localized into the micronucleus

Abstract Chromosomal Instability (CIN) is a characteristic of the most aggressive and drug-resistant cancers. Chromosomally unstable cells form micronuclei (MN), a structure with an unstable nuclear membrane that spontaneously surrounds missegregating chromosomes upon mitotic exit. Several studies have demonstrated that CIN drives drug resistance and metastasis through the karyotypic diversity caused by copy number alterations. Beyond facilitating karyotypic diversity, CIN has recently been demonstrated to cause durable epigenetic alterations including reduction of the activating histone H3K27ac mark in chromosomes localized to micronuclei. This reduction in histone H3K27 acetylation persists after the relocalization of the missegregated chromosome to the primary nucleus (PN). Given the loss of transcription-associated epigenetic modifications, we hypothesized that MN would exhibit transcriptional impairment. Indeed, by using nascent RNA assays and immunofluorescence, we found that chromosomes localized into the MN are less transcriptionally active and exhibit lower levels of active RNA polymerase II (RNAP2). Transcriptional inhibitors targeting RNAP2 largely abrogate MN transcription. Conversely, class-specific histone deacetylase inhibitors (HDACi) cause increased hyperacetylation of the MN relative to the PN, which persists beyond MN reincorporation into the PN. We also hypothesized that transcription in MN depends on the manner of MN biogenesis. Preliminary data shows that MN formed from breakage-fusion-bridge (BFB) events may cause less transcriptionally active MN than ones generated from treatment with the MPS1 inhibitor, reversine. To better understand the mechanisms that regulate transcription in the MN, our ongoing work is focused on an unbiased investigation of the micronuclear transcriptome. Citation Format: Danguole Norkunaite, Duaa Al-Rawi, Samuel Bakhoum. Transcriptional dysregulation of chromosomes localized into the micronucleus [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4400.

Abstract 2704: cGAS-STING drives myeloid inflammation in chromosomally unstable esophageal cancer

Abstract Esophageal adenocarcinoma (EAC) is an aggressive disease characterized by chromosomal instability (CIN), whereby cells continuously acquire chromosomal abnormalities that promote therapeutic resistance, immune evasion and metastasis. CIN in cancers also fuels the misplacement of genomic DNA in the form of structural abnormalities of the nucleus, such as micronuclei (MN), that lead to chronic activation of the cytosolic DNA sensing cGAS-STING pathway. However, how chronic cGAS-STING pathway activation is tolerated and shapes the tumor landscape of CINhigh EAC cancers is poorly understood. Using publicly available RNA-seq and genome sequencing data of EAC tumours and esophageal cancer cell lines as well as a panel of EAC cell lines, we demonstrate that the core cGAS-STING pathway machinery is rarely inactivated in EAC despite high levels of baseline CIN and aneuploidy. Through transcriptomic profiling of an isogenic EAC precursor cell line model of variable CIN and cGASKO/WT EAC cell lines we show that both chronic and transient CIN-driven cGAS-STING activation converge on the expression of CXCR1/2 ligands and other pro-inflammatory cytokines and chemokines rather than typical anti-tumor type I interferon signalling in EAC cells. Indeed, a novel transcriptional signature of cGAS+ micronuclear burden-correlated genes correlates with orthogonal measures of CIN in EAC tumours and esophagogastric cancer cell lines and is associated with an enrichment in myeloid-derived cells as well as poor prognosis. Correspondingly, using multiplexed immunofluorescence (IF) we find that a high preponderance of cGAS+MN and STING expression in human EAC samples is associated with decreased tumor purity, increased myeloid cell and macrophage infiltration, and increased peripheral blood neutrophil counts, indicative of tumor-promoting myeloid inflammation. Ongoing multiplexed IF and single-nuclei RNAseq analysis of cGAS+MNhigh and cGAS+MNlow EAC tumors will further help characterise the components that comprise the CIN EAC tumor microenvironment (TME) and the CIN- and cGAS-STING-dependent cell-cell interactions that govern it. Taken together, our findings provide an explanation for the observed maintenance of cGAS and STING in EAC and identify disruption of cGAS-STING-dependent myeloid cell inflammation and recruitment as a potential therapeutic target for CINhigh EAC. Citation Format: Bruno Beernaert, Erkin Erdal, Rose Clark, Tong Liu, Ester M. Hammond, Eileen E. Parkes. cGAS-STING drives myeloid inflammation in chromosomally unstable esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2704.

Abstract 1069: Interrogating the role of the cGAS/STING pathway fallopian tube transformation

Abstract Ovarian Cancer is the deadliest gynecologic malignancy. Despite recent advances in cancer diagnostics, it is a cancer that is often detected late and the vast majority of patients are diagnosed at Stage III and Stage IV. After treatment with debulking surgery and chemotherapy, 80% of patients have tumor relapse with increasing resistance. Early detection efforts have been largely unsuccessful and the only effective prevention strategy in high risk patients is surgical removal of the fallopian tube and ovaries. Careful pathologic studies of prophylactic risk reducing bilateral salpingo-oophorectomy (RRSO) has demonstrated that HGSC originates in the fallopian tube. Within the fallopian tube, secretory cells within the fimbriae are believed to be the origin of HGSC based on numerous lines of correlative evidence including the identification of histologically and molecularly abnormal regions in the fallopian tube called serous tubal intraepithelial cancer (STIC) in 3-5% of patients undergoing RRSO, and the presence of STIC in approximately half of patients undergoing debulking surgeries for HGSC. Finally, p53 mutations have been found to be identical in STIC and in the concurrent invasive disease indicating that HGSC and the STIC likely arise from the same clone. TCGA analysis has demonstrated that HCSC is a disease characterized by genomic and chromosomal instability harboring copy number alteration, including amplifications, deletions and more complex chromosomal rearrangements which impact multiple genes and pathways. Aberrantly segregating chromosomes that lag behind the spindle apparatus fail to become part of the primary nucleus (PN) and are instead enclosed by a self-assembled nuclear membrane, creating a structure called the micronucleus (MN). Spontaneous breakdown of the MN causes cytoplasmic DNA sensing and activation of the cGAS-STING pathway, an important innate cellular defense mechanism to foreign cytoplasmic DNA. To better understand the early genomic and signaling events in the development of HGSC, we are interrogating tissue from our archives from MSKCC patients who have undergone RRSO, hormone ablation surgeries or surgical debulking and were found to have benign fallopian tube, STIC lesions or invasive HGSC with STIC. We have performed a pilot experiment of 20 patient samples of different germline genetic backgrounds. Intriguingly, cGAS signaling was observed only rarely in the STICs indicating low rates of CIN in STICs we have evaluated, however we note that even in early invasive disease, we observe cGAS positivity. Taken together, these data are consistent with a model where CIN and subsequent cGAS/STING pathway activation drives the transition from pre-invasive to invasive disease. Citation Format: Duaa Hassan Al-Rawi, Danguole Norkunaite, Samuel Bakhoum, Sohrab Shah. Interrogating the role of the cGAS/STING pathway fallopian tube transformation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1069.

Induction of micronuclei in blood and histopathological alterations in gill, kidney and liver of Channa punctatus (Bloch, 1793) exposed to copper sulphate

Copper is one of the most toxic metals to fish and causes cytotoxic, mutagenic and carcinogenic effects. The accumulation of copper in an aquatic environment directly impacts man and the aquatic ecosystem. The present study aimed to determine the effect of copper sulphate (CuSO4) accumulation on the induction of micronuclei in blood and histological changes in kidney and liver of the fish Channa punctatus. The test chemical LC50 was determined after 96 hours during the first experiment. Later in the second experiment, the test animal was exposed to three sub-lethal concentrations of CuSO4 [0.1 mg/l (96 h-LC50/40), 0.2 mg/l (96 h-LC50/20) and 0.4 mg/l (96 h-LC50/10)]. Physico chemical parameters of the test medium, such as pH, temperature, hardness, alkalinity, and dissolved oxygen, were observed throughout the experiment, and all values were within the ranges necessary for the fish's survival. At intervals of 7, 14, 21, and 28 days, the control (without any test chemical) and copper sulphate exposed Groups' blood, liver, kidney, and gill tissues were taken to evaluate changes in genotoxic and histological parameters. Micronuclei (MN) induction and nuclear abnormalities (NAs) were observed at regular intervals. After 28 days, the MN frequency in Groups 1, 2, 3, and 4 was 0.78±0.006, 8.40±0.052, 10.37±0.098 and 10.90±0.024 respectively. A significant (P< 0.05) rise in MN frequencies and NAs indicated fish erythrocytes' DNA damage. Histological analysis of the liver, kidney, and gills revealed serious tissue injury such as necrosis, vacuolization, and degeneration after 28 days in the exposed Groups. The present study observed changes due to genotoxicity and histology, giving the most comprehensive understanding of CuSO4 stress on the fish C. punctatus and its risks to human health.

Evaluation of Genotoxic and Cytotoxic Activities of Leaf and Seed Extracts of Telfairia occidentalis

Telfairia occidentalis Hook (cucurbitaceae) leaves and seeds, which are used as vegetable in the preparation of soups and as medicine traditionally to treat various diseases by the Ibibios were investigated for genotoxic and cytotoxic effects using Allium cepa test. The effects of the leaves and seeds extracts on the root meristem cells of Allium cepa were investigated using onion bulbs exposed to 2.5 mg/mL, 5 mg/mL, and 10 mg/mL concentrations of the extracts for macroscopic and microscopic analysis. Tap water was used as a negative control and Methotrexate (0.1 mg/ml) was used as a positive control. There was statistically significant (p< 0.05) inhibition of root growth depending on concentration by the extracts when compared with the negative control group. All the tested extracts were observed to have cytotoxic effects on cell division in A. cepa. The extracts-induced chromosomal aberrations and micronuclei (MNC) formations in A. cepa root tip cells were significant (p<0.05) when compared with control group. The extracts treatment further induced cell death, ghost cells, cells membrane damage, and binucleated cells. The seed extract was found to have a higher cytotoxic and genotoxic effects than the leaf extract. These results suggest that the leaf and seeds extract of Telfairia occidentalis possess cytotoxic and genotoxic effects on A. cepa.

Exploring cytokinesis block micronucleus assay in Croatia: A journey through the past, present, and future in biomonitoring of the general population

In this study, we used the cytokinesis-block micronucleus (CBMN) assay to evaluate the background frequency of cytogenetic damage in peripheral blood lymphocytes of the general population concerning different anthropometric data and lifestyle factors. The background frequency of CBMN assay parameters was analysed in 850 healthy, occupationally non-exposed male and female subjects (average age, 38±11 years) gathered from the general Croatian population from 2000 to 2023. The mean background values for micronuclei (MNi) in the whole population were 5.3±4.3 per 1000 binucleated cells, while the mean frequency of nucleoplasmic bridges (NPBs) was 0.7±1.3 and of nuclear buds (NBUDs) 3.1±3.2. The cut-off value, which corresponds to the 95th percentile of the distribution of 850 individual values, was 14 MNi, 3 NPBs, and 9 NBUDs. Results from our database also showed an association of the tested genomic instability parameters with age and sex but also with other lifestyle factors. These findings underscore the importance of considering several anthropometric and lifestyle factors when conducting biomonitoring studies. Overall, the normal and cut-off values attained here present normal values for the general population that can later serve as baseline values for further human biomonitoring studies either in Croatia or worldwide.

Repression of the SUMO-conjugating enzyme UBC9 is associated with lowered double minutes and reduced tumor progression

ABSTRACT Double minutes (DMs), extrachromosomal gene fragments found within certain tumors, have been noted to carry onco- and drug resistance genes contributing to tumor pathogenesis and progression. After screening for SUMO-related molecule expression within various tumor sample and cell line databases, we found that SUMO-conjugating enzyme UBC9 has been associated with genome instability and tumor cell DM counts, which was confirmed both in vitro and in vivo. Karyotyping determined DM counts post-UBC9 knockdown or SUMOylation inhibitor 2-D08, while RT-qPCR and Western blot were used to measure DM-carried gene expression in vitro. In vivo, fluorescence in situ hybridization (FISH) identified micronucleus (MN) expulsion. Western blot and immunofluorescence staining were then used to determine DNA damage extent, and a reporter plasmid system was constructed to detect changes in homologous recombination (HR) and non-homologous end joining (NHEJ) pathways. Our research has shown that UBC9 inhibition is able to attenuate DM formation and lower DM-carried gene expression, in turn reducing tumor growth and malignant phenotype, via MN efflux of DMs and lowering NHEJ activity to increase DNA damage. These findings thus reveal a relationship between heightened UBC9 activity, increased DM counts, and tumor progression, providing a potential approach for targeted therapies, via UBC9 inhibition.

ATR signaling controls the bystander responses of human chondrosarcoma cells by promoting RAD51-dependent DNA repair

Purpose Radiation-induced bystander effect (RIBE) frequently is seen as DNA damage in unirradiated bystander cells, but the repair processes initiated in response to that DNA damage are not well understood. RIBE-mediated formation of micronuclei (MN), a biomarker of persistent DNA damage, was previously observed in bystander normal fibroblast (AG01522) cells, but not in bystander human chondrosarcoma (HTB94) cells. The molecular mechanisms causing this disparity are not clear. Herein, we investigate the role of DNA repair in the bystander responses of the two cell lines. Methods Cells were irradiated with X-rays and immediately co-cultured with un-irradiated cells using a trans-well insert system in which they share the same medium. The activation of DNA damage response (DDR) proteins was detected by immunofluorescence staining or Western blotting. MN formation was examined by the cytokinesis-block MN assay, which is a robust method to detect persistent DNA damage. Results Immunofluorescent foci of γH2AX and 53BP1, biomarkers of DNA damage and repair, revealed a greater capacity for DNA repair in HTB94 cells than in AG01522 cells in both irradiated and bystander populations. Autophosphorylation of ATR at the threonine 1989 site was expressed at a greater level in HTB94 cells compared to AG01522 cells at the baseline and in response to hydroxyurea treatment or exposure to 1 Gy of X-rays. An inhibitor of ATR, but not of ATM, promoted MN formation in bystander HTB94 cells. In contrast, no effect of either inhibitor was observed in bystander AG01522 cells, indicating that ATR signaling might be a pivotal pathway to preventing the MN formation in bystander HTB94 cells. Supporting this idea, we found an ATR-dependent increase in the fractions of bystander HTB94 cells with pRPA2 S33 and RAD51 foci. A blocker of RAD51 facilitated MN formation in bystander HTB94 cells. Conclusion Our results indicate that HTB94 cells were likely more efficient in DNA repair than AG01522 cells, specifically via ATR signaling, which inhibited the bystander signal-induced MN formation. This study highlights the significance of DNA repair efficiency in bystander cell responses.

Phytochemical Profile and Evaluation of the Antioxidant, Cyto-Genotoxic, and Antigenotoxic Potential of Salvia verticillata Hydromethanolic Extract.

This study comprises the phytochemical characterization, the evaluation of the total phenolic content (TPC) and antioxidant activity (AA), and the investigation of the cyto-genotoxic and antigenotoxic potential of hydromethanolic extract derived from Salvia verticillata L. leaves. HPLC-DAD-ESI-MS and HPLC-DAD were used for the characterization of the extract and determination of the major ingredients. Afterwards, the TPC and AA were determined. The cytotoxic and genotoxic effect of the extract on cultured human lymphocytes at concentrations of 10, 25, and 50 μg mL-1 was investigated via the Cytokinesis Block MicroNucleus (CBMN) assay. Moreover, its antigenotoxic potential against the mutagenic agent mitomycin C (MMC) was assessed using the same assay. The hydromethanolic extract comprises numerous metabolites, with rosmarinic acid being the major compound. It had a high value of TPC and exerted significant AA as shown by the results of the Ferric Reducing Antioxidant Power (FRAP) and Radical Scavenging Activity by DPPH• assays. A dose-dependent cytotoxic potential was recorded, with the highest dose (50 μg mL-1) exhibiting statistically significant cytotoxicity. None of the tested concentrations induced significant micronuclei (MN) frequencies, indicating a lack of genotoxicity. All tested concentrations reduced the MMC-mediated genotoxic effects, with the two lowest showing statistically significant antigenotoxic potential.

Evaluation of micronuclei, cytomorphometric and cytologic changes of the oral mucosa in hookah and cigarette smokers

To analyze the effect of hookah and cigarettes on the oral mucosa of smokers through the use of exfoliative cytology. Smear samples were collected by exfoliative cytology from the tongue of 33 hookah smokers, 22 cigarette smokers, and 30 non-smokers. The selected analyses include micronuclei (MN), metanuclear anomalies, epithelial maturation, and cytomorphology (nuclear area [NA], cytoplasmic area [CA], and NA/CA ratio). The largest differences observed for MN and metanuclear anomalies were between cigarette smokers and the control group (notably 1 MN P = .04; total cells with MN P = .039; total MN P = .042; karyorrhexis and binucleation, P = .0001). The hookah group, compared with the control group, showed the greatest differences for karyolysis (P = .0023), binucleation (P = .0003), and broken egg (P = .008). Significant differences were found between the smokers and the control groups regarding changes in the superficial cell without nucleus, perinuclear halo, vacuolization, color change, mucus, and keratohyalin granules. There was a significant increase in the NA and NA/CA ratio in the smoker groups. This study showed that a combined analysis of exfoliative cytology associated with other diagnostic methods is a useful tool for studying oral carcinogenesis. Hookah and cigarettes showed similar effects in terms of displaying substantial cytogenetic and cytotoxic damage.

The proteomic landscape of genotoxic stress-induced micronuclei

Micronuclei (MN) are induced by various genotoxic stressors and amass nuclear- and cytoplasmic-resident proteins, priming the cell for MN-driven signaling cascades. Here, we measured the proteome of micronuclear, cytoplasmic, and nuclear fractions from human cells exposed to a panel of six genotoxins, comprehensively profiling their MN protein landscape. We find that MN assemble a proteome distinct from both surrounding cytoplasm and parental nuclei, depleted of spliceosome and DNA damage repair components while enriched for a subset of the replisome. We show that the depletion of splicing machinery within transcriptionally active MN contributes to intra-MN DNA damage, a known precursor to chromothripsis. The presence of transcription machinery in MN is stress-dependent, causing a contextual induction of MN DNA damage through spliceosome deficiency. This dataset represents a unique resource detailing the global proteome of MN, guiding mechanistic studies of MN generation and MN-associated outcomes of genotoxic stress.

Effect of the Neonicotinoid Insecticide Thiacloprid on Oxidative Stress, Genotoxic, and Immunotoxic Biomarkers in Greater Wax Moth, Galleria mellonella

The aim of this study was to investigate the effect of the neonicotinoid insecticide Thiacloprid on oxidative stress, genotoxic, and immunotoxic biomarkers in Galleria mellonella. The effects of neonicotinoid insecticide thiacloprid on antioxidant enzyme activities, malondialdehyde (MDA) levels, hemocyte number, micronucleus frequency of greater wax moth (Galleria mellonella) larvae at different doses (5, 10, 15, 20, 25, and 30 µg) and periods (24, 48, 72, and 96 hrs) were explored. Superoxide dismutase (SOD) activity increased significantly at 5, 10, and 15 µg thiacloprid doses compared to the control and negative control in all periods tested, while significantly decreased at 20, 25, and 30 µg doses. Catalase (CAT) activity showed significant increases at 5, 10 and 15 µg thiacloprid doses at 24 and 96h compared to the control and negative control. MDA concentrations showed significant increases in all periods compared to the control and negative control. At 24th, 48th, 72nd and 96th, total hemocyte count (THC) decreased significantly at all doses except 5 µg thiacloprid concentration. During all the tested periods, there was a significant increase in the number of micronuclei, particularly at high doses of thiacloprid (20, 25, and 30 µg) compared to both the control and negative control. Additionally, a positive correlation was observed between MDA and the number of micronuclei, while other markers showed a negative correlation with micronucleus (MN). These results suggest that high doses of thiacloprid induce significant increases in micronuclei formation and are positively correlated with MDA levels, indicating oxidative damage and genotoxicity caused by thiacloprid exposure in the tested organism. Overall, our findings suggest that the measured parameters can be considered reliable biomarkers to demonstrate oxidative damage from thiacloprid exposure.

Safety assessment of high fructose corn syrup and fructose used as sweeteners in foods

High Fructose Corn Syrup (HFCS) and Fructose (FR) are widely used sweeteners in many foods and beverages. This study aimed at investigating the cytotoxic effects of HFCS (5%–30%) and FR (62.5–2000 μg/mL) using MTT assay in Human Hepatocellular Carcinoma (HepG2) cells, and genotoxic effects of using Chromosome Aberrations (CAs), Sister Chromatid Exchanges (SCEs), Micronuclei (MN) and comet assays in human lymphocytes. HFCS significantly reduced the cell viability in HepG2 cells at between 7.5% and 30% for 24 and 48 h. 30% HFCS caused a very significant toxic effect. FR had a cytotoxic effect in HepG2 cells at all treatments. However, as fructose concentration decreased, the cell viability decreased. HFCS (10%–20%) and FR (250–2000 μg/mL) decreased the mitotic index at higher concentrations. IC50 value was found to be a 15% for 48 h. IC50 value of FR was detected as 62.5 μg/mL for 24 h and 48 h. HFCS significantly increased CAs frequency at 15% and 20%. FR significantly increased the frequency of CAs at 250, 1000, and 2000 μg/mL for 48 h. Both sweeteners increased the frequency of SCEs at all concentrations. HFCS (15% and 20%) and FR (250, 1000, and 2000 μg/mL) induced MN frequency at higher concentrations. HFCS caused DNA damage in comet assay at 10% −30%. FR increased tail intensity and moment at 125-2000 μg/mL and tail length at 62.5, 250 and 500 μg/mL. Therefore, HFCS and FR are clearly seen to be cytotoxic and genotoxic, especially at higher concentrations.