ABSTRACT
Glufosinate-ammonium (GLA), an organophosphate herbicide, is released at high concentrations in the environment, leading to concerns over its potential genotoxic effects. However, few articles are available in the literature reporting the possible cellular and nuclear effects of this compound. We assessed, by in vitro and in vivo micronucleus assays, the genotoxicity of GLA on cultured human lymphocytes and Lymnaea stagnalis hemocytes at six concentrations: 0.010 (the established acceptable daily intake value), 0.020, 0.050, 0.100, 0.200, and 0.500 µg/mL. In human lymphocytes, our results reveal a significant and concentration-dependent increase in micronuclei frequency at concentrations from 0.100 to 0.500 µg/mL, while in L. stagnalis hemocytes, significant differences were found at 0.200 and 0.500 µg/mL. A significant reduction in the proliferation index was observed at all tested concentrations, with the only exception of 0.010 µg/mL, indicating that the exposure to GLA could lead to increased cytotoxic effects. In L. stagnalis, a significant reduction in laid eggs and body growth was also observed at all concentrations. In conclusion, we provided evidence of the genomic and cellular damage induced by GLA on both cultured human lymphocytes and a model organism's hemocytes; in addition, we also demonstrated its effects on cell proliferation and reproductive health in L. stagnalis.
Subject(s)
Aminobutyrates , Genomic Instability , Hemocytes , Herbicides , Lymphocytes , Herbicides/toxicity , Aminobutyrates/pharmacology , Humans , Animals , Genomic Instability/drug effects , Lymphocytes/drug effects , Lymphocytes/metabolism , Hemocytes/drug effects , Micronucleus Tests , Cell Proliferation/drug effectsABSTRACT
Indoor air pollution is becoming a rising public health problem and is largely resulting from the burning of solid fuels and heating in households. Burning these fuels produces harmful compounds, such as particulate matter regarded as a major health risk, particularly affecting the onset and exacerbation of respiratory diseases. As exposure to polluted indoor air can cause DNA damage including DNA sd breaks as well as chromosomal damage, in this paper, we aim to provide an overview of the impact of indoor air pollution on DNA damage and genome stability by reviewing the scientific papers that have used the comet, micronucleus, and γ-H2AX assays. These methods are valuable tools in human biomonitoring and for studying the mechanisms of action of various pollutants, and are readily used for the assessment of primary DNA damage and genome instability induced by air pollutants by measuring different aspects of DNA and chromosomal damage. Based on our search, in selected studies (in vitro, animal models, and human biomonitoring), we found generally higher levels of DNA strand breaks and chromosomal damage due to indoor air pollutants compared to matched control or unexposed groups. In summary, our systematic review reveals the importance of the comet, micronucleus, and γ-H2AX assays as sensitive tools for the evaluation of DNA and genome damaging potential of different indoor air pollutants. Additionally, research in this particular direction is warranted since little is still known about the level of indoor air pollution in households or public buildings and its impact on genetic material. Future studies should focus on research investigating the possible impact of indoor air pollutants in complex mixtures on the genome and relate pollutants to possible health outcomes.
Subject(s)
Air Pollutants , Air Pollution, Indoor , DNA Damage , Micronucleus Tests , Air Pollution, Indoor/adverse effects , Air Pollution, Indoor/analysis , Humans , Animals , Air Pollutants/toxicity , Chromosomal Instability/drug effects , Comet Assay , Particulate Matter/toxicity , Particulate Matter/analysis , Histones/metabolism , Environmental Monitoring/methods , Genomic Instability/drug effects , Biological Monitoring/methodsABSTRACT
Ovarian cancer is the leading cause of gynecologic cancer death. Among the most innovative anti-cancer approaches, the genetic concept of synthetic lethality is that mutations in multiple genes work synergistically to effect cell death. Previous studies found that although vaccinia-related kinase-1 (VRK1) associates with DNA damage repair proteins, its underlying mechanisms remain unclear. Here, we found high VRK1 expression in ovarian tumors, and that VRK1 depletion can significantly promote apoptosis and cell cycle arrest. The effect of VRK1 knockdown on apoptosis was manifested by increased DNA damage, genomic instability, and apoptosis, and also blocked non-homologous end joining (NHEJ) by destabilizing DNA-PK. Further, we verified that VRK1 depletion enhanced sensitivity to a PARP inhibitor (PARPi), olaparib, promoting apoptosis through DNA damage, especially in ovarian cancer cell lines with high VRK1 expression. Proteins implicated in DNA damage responses are suitable targets for the development of new anti-cancer therapeutic strategies, and their combination could represent an alternative form of synthetic lethality. Therefore, normal protective DNA damage responses are impaired by combining olaparib with elimination of VRK1 and could be used to reduce drug dose and its associated toxicity. In summary, VRK1 represents both a potential biomarker for PARPi sensitivity, and a new DDR-associated therapeutic target, in ovarian cancer.
Subject(s)
DNA Damage , DNA-Activated Protein Kinase , Intracellular Signaling Peptides and Proteins , Ovarian Neoplasms , Protein Serine-Threonine Kinases , Female , Humans , Apoptosis/drug effects , Cell Line, Tumor , DNA Damage/drug effects , DNA-Activated Protein Kinase/metabolism , DNA-Activated Protein Kinase/genetics , Gene Expression Regulation, Neoplastic/drug effects , Genomic Instability/drug effects , Intracellular Signaling Peptides and Proteins/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Ovarian Neoplasms/metabolism , Phthalazines/pharmacology , Piperazines/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/geneticsABSTRACT
DNA double-strand breaks (DSBs) are functionally linked to genomic instability in spermatocytes and to male infertility. The heavy metal cadmium (Cd) is known to induce DNA damage in spermatocytes by unknown mechanisms. Here, we showed that Cd ions impaired the canonical non-homologous end-joining (NHEJ) repair pathway, but not the homologous recombination (HR) repair pathway, through stimulation of Ser2056 and Thr2609 phosphorylation of DNA-PKcs at DSB sites. Hyper-phosphorylation of DNA-PKcs led to its premature dissociation from DNA ends and the Ku complex, preventing recruitment of processing enzymes and further ligation of DNA ends. Specifically, this cascade was initiated by the loss of PP5 phosphatase activity, which results from the dissociation of PP5 from its activating ions (Mn), that is antagonized by Cd ions through a competitive mechanism. In accordance, in a mouse model Cd-induced genomic instability and consequential male reproductive dysfunction were effectively reversed by a high dosage of Mn ions. Together, our findings corroborate a protein phosphorylation-mediated genomic instability pathway in spermatocytes that is triggered by exchange of heavy metal ions.
Subject(s)
Cadmium , Genomic Instability , Infertility, Male , Spermatocytes , Animals , Humans , Male , Mice , Cadmium/toxicity , DNA/metabolism , DNA End-Joining Repair , DNA Repair , Genomic Instability/drug effects , Infertility, Male/genetics , Infertility, Male/metabolism , Ions/metabolism , Phosphorylation , Recombinational DNA Repair , Spermatocytes/drug effectsABSTRACT
Fanconi Anemia (FA) is a rare, genome instability-associated disease characterized by a deficiency in repairing DNA crosslinks, which are known to perturb several cellular processes, including DNA transcription, replication, and repair. Formaldehyde, a by-product of metabolism, is thought to drive FA by generating DNA interstrand crosslinks (ICLs) and DNA-protein crosslinks (DPCs). However, the impact of formaldehyde on global cellular pathways has not been investigated thoroughly. Herein, using a pangenomic CRISPR-Cas9 screen, we identify EXO1 as a critical regulator of formaldehyde-induced DNA lesions. We show that EXO1 knockout cell lines exhibit formaldehyde sensitivity leading to the accumulation of replicative stress, DNA double-strand breaks, and quadriradial chromosomes, a typical feature of FA. After formaldehyde exposure, EXO1 is recruited to chromatin, protects DNA replication forks from degradation, and functions in parallel with the FA pathway to promote cell survival. In vitro, EXO1-mediated exonuclease activity is proficient in removing DPCs. Collectively, we show that EXO1 limits replication stress and DNA damage to counteract formaldehyde-induced genome instability.
Subject(s)
CRISPR-Cas Systems , Drug Tolerance , Exodeoxyribonucleases , Fanconi Anemia , Formaldehyde , Humans , DNA , DNA Damage/drug effects , DNA Damage/genetics , DNA Repair/drug effects , DNA Repair/genetics , DNA Repair Enzymes/genetics , DNA Repair Enzymes/metabolism , DNA Replication/drug effects , DNA Replication/genetics , Exodeoxyribonucleases/genetics , Exodeoxyribonucleases/metabolism , Fanconi Anemia/chemically induced , Fanconi Anemia/genetics , Formaldehyde/toxicity , Genomic Instability/drug effects , Genomic Instability/genetics , Drug Tolerance/geneticsABSTRACT
The DNA damage response (DDR) pathway generally protects against genome instability, and defects in DDR have been exploited therapeutically in cancer treatment. We have reported that histone demethylase PHF8 demethylates TOPBP1 K118 mono-methylation (K118me1) to drive the activation of ATR kinase, one of the master regulators of replication stress. However, whether dysregulation of this physiological signalling is involved in tumorigenesis remains unknown. Here, we showed PHF8-promoted TOPBP1 demethylation is clinically associated with breast tumorigenesis and patient survival. Mammary gland tumors from Phf8 knockout mice grow slowly and exhibit higher level of K118me1, lower ATR activity, and increased chromosomal instability. Importantly, we found that disruption of PHF8-TOPBP1 axis suppresses breast tumorigenesis and creates a breast tumor-specific vulnerability to PARP inhibitor (PARPi) and platinum drug. CRISPR/Cas9 mutation modelling of the deleted or truncated mutation of PHF8 in clinical tumor samples demonstrated breast tumor cells expressing the mimetic variants are more vulnerable to PARPi. Together, our study supports the pursuit of PHF8-TOPBP1 signalling pathway as promising avenues for targeted therapies of PHF8-TOPBP1 proficient tumors, and provides proof-of-concept evidence for loss-of-function of PHF8 as a therapeutic indicator of PARPis.
Subject(s)
Breast Neoplasms/metabolism , Carrier Proteins/metabolism , DNA-Binding Proteins/metabolism , Histone Demethylases/metabolism , Nuclear Proteins/metabolism , Transcription Factors/metabolism , Animals , Breast Neoplasms/drug therapy , Carcinogenesis/drug effects , Carcinogenesis/metabolism , Cell Line , Cell Line, Tumor , Cell Transformation, Neoplastic/drug effects , Cell Transformation, Neoplastic/metabolism , Female , Genomic Instability/drug effects , Genomic Instability/physiology , HEK293 Cells , HeLa Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Signal Transduction/drug effects , Signal Transduction/physiologyABSTRACT
Glioblastoma (GBM) is associated with a very dismal prognosis, and current therapeutic options still retain an overall unsatisfactorily efficacy in clinical practice. Therefore, novel therapeutic approaches and effective medications are highly needed. Since the development of new drugs is an extremely long, complex and expensive process, researchers and clinicians are increasingly considering drug repositioning/repurposing as a valid alternative to the standard research process. Drug repurposing is also under active investigation in GBM therapy, since a wide range of noncancer and cancer therapeutics have been proposed or investigated in clinical trials. Among these, a remarkable role is played by the antipsychotic drugs, thanks to some still partially unexplored, interesting features of these agents. Indeed, antipsychotic drugs have been described to interfere at variable incisiveness with most hallmarks of cancer. In this review, we analyze the effects of antipsychotics in oncology and how these drugs can interfere with the hallmarks of cancer in GBM. Overall, according to available evidence, mostly at the preclinical level, it is possible to speculate that repurposing of antipsychotics in GBM therapy might contribute to providing potentially effective and inexpensive therapies for patients with this disease.
Subject(s)
Antipsychotic Agents/therapeutic use , Drug Repositioning , Glioblastoma/drug therapy , Glioblastoma/genetics , Animals , Antipsychotic Agents/pharmacology , Cell Line, Tumor , Genomic Instability/drug effects , Humans , NeurogenesisABSTRACT
The SARS-CoV-2 coronavirus is the causal agent of the current global pandemic. SARS-CoV-2 belongs to an order, Nidovirales, with very large RNA genomes. It is proposed that the fidelity of coronavirus (CoV) genome replication is aided by an RNA nuclease complex, comprising the non-structural proteins 14 and 10 (nsp14-nsp10), an attractive target for antiviral inhibition. Our results validate reports that the SARS-CoV-2 nsp14-nsp10 complex has RNase activity. Detailed functional characterization reveals nsp14-nsp10 is a versatile nuclease capable of digesting a wide variety of RNA structures, including those with a blocked 3'-terminus. Consistent with a role in maintaining viral genome integrity during replication, we find that nsp14-nsp10 activity is enhanced by the viral RNA-dependent RNA polymerase complex (RdRp) consisting of nsp12-nsp7-nsp8 (nsp12-7-8) and demonstrate that this stimulation is mediated by nsp8. We propose that the role of nsp14-nsp10 in maintaining replication fidelity goes beyond classical proofreading by purging the nascent replicating RNA strand of a range of potentially replication-terminating aberrations. Using our developed assays, we identify drug and drug-like molecules that inhibit nsp14-nsp10, including the known SARS-CoV-2 major protease (Mpro) inhibitor ebselen and the HIV integrase inhibitor raltegravir, revealing the potential for multifunctional inhibitors in COVID-19 treatment.
Subject(s)
Antiviral Agents/pharmacology , Drug Evaluation, Preclinical , Exoribonucleases/metabolism , Genome, Viral/genetics , Genomic Instability , SARS-CoV-2/enzymology , SARS-CoV-2/genetics , Viral Nonstructural Proteins/metabolism , Viral Regulatory and Accessory Proteins/metabolism , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Exoribonucleases/antagonists & inhibitors , Genome, Viral/drug effects , Genomic Instability/drug effects , Genomic Instability/genetics , HIV Integrase Inhibitors/pharmacology , Isoindoles/pharmacology , Multienzyme Complexes/antagonists & inhibitors , Multienzyme Complexes/metabolism , Organoselenium Compounds/pharmacology , RNA, Viral/biosynthesis , RNA, Viral/genetics , Raltegravir Potassium/pharmacology , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Regulatory and Accessory Proteins/antagonists & inhibitors , Virus Replication/drug effects , Virus Replication/geneticsABSTRACT
Genotoxic agents are widely used anti-cancer therapies because of their ability to interfere with highly proliferative cells. An important outcome of these interventions is the induction of a state of permanent arrest also known as cellular senescence. However, senescent cancer cells are characterized by genomic instability and are at risk of escaping the growth arrest to eventually facilitate cancer relapse. The tumor necrosis factor related apoptosis inducing ligand (TRAIL) signals extrinsic apoptosis via Death Receptors (DR) 4 and 5, while Decoy Receptors (DcR) 1 and 2, and Osteoprotegerin (OPG) are homologous to death receptors but incapable of transducing an apoptotic signal. The use of recombinant TRAIL as an anti-cancer strategy in combination with chemotherapy is currently in development, and a major question remains whether senescent cancer cells respond to TRAIL. Here, we show variable sensitivity of cancer cells to TRAIL after senescence induction, and upregulation of both pro-apoptotic and anti-apoptotic receptors in therapy-induced senescent cancer cells. A DR5-selective TRAIL variant (DHER), unable to bind to DcR1 or OPG, was more effective in inducing apoptosis of senescent cancer cells compared to wild-type TRAIL. Importantly, no apoptosis induction was observed in non-cancerous cells, even at the highest concentrations tested. Our results suggest that targeting DR5 can serve as a novel therapeutic strategy for the elimination of therapy-induced senescent cancer cells.
Subject(s)
Breast Neoplasms/drug therapy , Osteoprotegerin/genetics , Ovarian Neoplasms/drug therapy , Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics , TNF-Related Apoptosis-Inducing Ligand/genetics , Apoptosis/genetics , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cellular Senescence/drug effects , Cellular Senescence/genetics , Doxorubicin/pharmacology , Female , GPI-Linked Proteins/genetics , Gene Expression Regulation, Neoplastic/drug effects , Genomic Instability/drug effects , Humans , MCF-7 Cells , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Receptors, Tumor Necrosis Factor, Member 10c/genetics , Signal Transduction/drug effects , Tumor Necrosis Factor Decoy Receptors/geneticsABSTRACT
Inspired by natural saccharide-protein complexes, a stimuli-responsive biodegradable and branched glycopolymer-pyropheophorbide-a (Ppa) conjugate (BSP) with saccharide units for cancer therapy is constructed. A linear glycopolymeric conjugate (LSP), a branched glycopolymeric conjugate (BShP) from Ppa with long carbon chains, and a branched conjugate (BHSP) based on poly[N-(2-hydroxypropyl) methacrylamide] (polyHPMA) without saccharide units are prepared as controls. Through structure-activity relationship studies, BSP with a 3D network structure forms stable nanostructures via weak intermolecular interactions, regulating the stacking state of Ppa to improve the singlet oxygen quantum yield and the corresponding photodynamic therapy (PDT) effect. BSP shows high loading of olaparib, and are further coated with tumor cell membranes, resulting in a biomimetic nanomedicine (CM-BSPO). CM-BSPO shows highly efficient tumor targeting and cellular internalization properties. The engulfment of CM-BSPO accompanied with laser irradiation results in a prominent antitumor effect, evidenced by disruption of cell cycles in tumor cells, increased apoptosis and DNA damage, and subsequent inhibition of repair for damaged DNA. The mechanism for the synergistic effect from PDT and olaparib is unveiled at the genetic and protein level through transcriptome analysis. Overall, this biodegradable and branched glycopolymer-drug conjugate could be effectively optimized as a biomimetic nanomedicine for cancer therapy.
Subject(s)
Biomimetic Materials/chemistry , Genomic Instability , Nanomedicine , Polysaccharides/chemistry , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Apoptosis/drug effects , Cell Line, Tumor , Chlorophyll/analogs & derivatives , Chlorophyll/chemistry , DNA Damage/drug effects , Drug Carriers/chemistry , Genomic Instability/drug effects , Humans , Light , Mice , Nanostructures/chemistry , Neoplasms/drug therapy , Photochemotherapy/methods , Phthalazines/chemistry , Phthalazines/metabolism , Phthalazines/pharmacology , Phthalazines/therapeutic use , Piperazines/chemistry , Piperazines/metabolism , Piperazines/pharmacology , Piperazines/therapeutic use , Polymethacrylic Acids/chemistry , Reactive Oxygen Species/metabolismABSTRACT
Telomere instability is one of the main sources of genome instability and may result from chromosome end loss (due to chromosome breakage at one or both ends) or, more frequently, telomere dysfunction. Dysfunctional telomeres arise when they lose their end-capping function or become critically short, which causes chromosomal termini to behave like a DNA double-strand break. Telomere instability may occur at the chromosomal or at the molecular level, giving rise, respectively, to telomere-related chromosomal aberrations or the loss or modification of any of the components of the telomere (telomere DNA, telomere-associated proteins, or telomere RNA). Since telomeres play a fundamental role in maintaining genome stability, the study of telomere instability in cells exposed to mutagens is of great importance to understand the telomere-driven genomic instability present in those cells. In the present review, we will focus on the current knowledge about telomere instability induced by physical, chemical, and biological mutagens in human cells.
Subject(s)
Chromosomal Instability/drug effects , Genomic Instability/drug effects , Mutagens/toxicity , Telomere/drug effects , Animals , Cellular Senescence/drug effects , Cellular Senescence/genetics , Chromosomal Instability/genetics , DNA/genetics , DNA Breaks, Double-Stranded/drug effects , Genomic Instability/genetics , Humans , Telomere/geneticsABSTRACT
The present study investigated the protective effect of methanolic leaf extract of Morinda tinctoria. Roxb (MEMT) (200 mg/kg) via feed in supplementation with standard compound silymarin (400 mg/kg). M. tinctoria (Roxb.) belonging to Rubiaceae, is an evergreen shrub indigenous to unfarmed lands of tropical countries. It is considered as an essential traditional medicine attributing for the potential antioxidant and anti-inflammatory properties. The enhancements of antioxidant and antigenotoxic status in different tissues of cadmium (Cd) intoxicated Pangasius sutchi were evaluated by using various antioxidant assays (superoxide dismutase (SOD) and catalase (CAT) and lipid peroxidation) in addition to micronuclei (MN), binuclei (BN) and comet assay. The cadmium toxicated fish showed a significant (p < 0.001) increase in lipid peroxidation (LPO) activities in liver, gills, muscle and kidney whereas significant (p < 0.001) decline were observed in superoxide dismutase (SOD) and catalase (CAT) contents in all fish tissues. The results also revealed that, Cd exposure induced the formation of genotoxic endpoints like MN, BN, notched nuclei, kidney shaped nuclei and DNA damage in the fish erythrocytes. Maximum of 26.8% MN frequencies and maximum of 66.74% tail DNA damage were observed on the 7th day of Cd exposure. A time-dependent significant increase (p < 0.001) in the frequencies of MN, BN and tail DNA damage were observed in all treated groups against the control which started to decline from 14th day onwards. There was a decline in the LPO content, frequencies of MN, BN and percentage of tail DNA in contrast to significant elevation in SOD and CAT content in all tissues due to the combined treatment of M. tinctoria feed and water borne Cd exposure. It can be concluded from our observations that, supplementation of M. tinctoria leaf extract through feed alone produced enhanced antioxidant and antigenotoxic status in cadmium treated fish by diminishing oxidative stress and genotoxicity effects in a time dependent manner.
Subject(s)
Antioxidants/pharmacology , Cadmium/toxicity , Catfishes , Morinda/chemistry , Plant Extracts/pharmacology , Animals , Antioxidants/metabolism , Cadmium/administration & dosage , Cadmium/analysis , Cadmium/pharmacokinetics , Catalase/metabolism , Catfishes/physiology , DNA Damage , Dietary Supplements , Fish Proteins/metabolism , Genomic Instability/drug effects , Lethal Dose 50 , Lipid Peroxidation/drug effects , Micronucleus Tests , Plant Extracts/chemistry , Plant Leaves/chemistry , Superoxide Dismutase/metabolism , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicityABSTRACT
Developing novel targeted anticancer therapies is a major goal of current research. The use of poly(ADP-ribose) polymerase (PARP) inhibitors in patients with homologous recombination-deficient tumours provides one of the best examples of a targeted therapy that has been successfully translated into the clinic. The success of this approach has so far led to the approval of four different PARP inhibitors for the treatment of several types of cancers and a total of seven different compounds are currently under clinical investigation for various indications. Clinical trials have demonstrated promising response rates among patients receiving PARP inhibitors, although the majority will inevitably develop resistance. Preclinical and clinical data have revealed multiple mechanisms of resistance and current efforts are focused on developing strategies to address this challenge. In this Review, we summarize the diverse processes underlying resistance to PARP inhibitors and discuss the potential strategies that might overcome these mechanisms such as combinations with chemotherapies, targeting the acquired vulnerabilities associated with resistance to PARP inhibitors or suppressing genomic instability.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Drug Resistance, Neoplasm , Neoplasms/drug therapy , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Clinical Trials as Topic , Drug Resistance, Neoplasm/drug effects , Drug Therapy , Genomic Instability/drug effects , Humans , Neoplasms/geneticsABSTRACT
Platinum-based chemotherapy remains the cornerstone of treatment for most non-small cell lung cancer (NSCLC) cases either as maintenance therapy or in combination with immunotherapy. However, resistance remains a primary issue. Our findings point to the possibility of exploiting levels of cell division cycle associated protein-3 (CDCA3) to improve response of NSCLC tumours to therapy. We demonstrate that in patients and in vitro analyses, CDCA3 levels correlate with measures of genome instability and platinum sensitivity, whereby CDCA3high tumours are sensitive to cisplatin and carboplatin. In NSCLC, CDCA3 protein levels are regulated by the ubiquitin ligase APC/C and cofactor Cdh1. Here, we identified that the degradation of CDCA3 is modulated by activity of casein kinase 2 (CK2) which promotes an interaction between CDCA3 and Cdh1. Supporting this, pharmacological inhibition of CK2 with CX-4945 disrupts CDCA3 degradation, elevating CDCA3 levels and increasing sensitivity to platinum agents. We propose that combining CK2 inhibitors with platinum-based chemotherapy could enhance platinum efficacy in CDCA3low NSCLC tumours and benefit patients.
Subject(s)
Carcinoma, Non-Small-Cell Lung/metabolism , Drug Resistance, Neoplasm/genetics , Antigens, CD/metabolism , Biomarkers, Pharmacological/blood , Cadherins/metabolism , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Casein Kinase II/antagonists & inhibitors , Casein Kinase II/metabolism , Cell Cycle/genetics , Cell Cycle Proteins/analysis , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cell Proliferation/genetics , Databases, Genetic , Drug Resistance, Neoplasm/physiology , Drug Therapy/methods , Genomic Instability/drug effects , Genomic Instability/genetics , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Platinum/therapeutic useABSTRACT
The increased life expectancy of people living with HIV (PLWH) receiving antiretroviral treatment (ART) has transformed HIV infection into a chronic disease. However, patients may be at risk of accelerated aging and the accumulation of cellular damage, which may trigger the development of cancer. We evaluated genomic instability in HIV-positive individuals with different viral loads receiving antiretroviral treatment (ART) and in HIV ART-naïve individuals. We included 67 participants divided into four groups: group 1 (n = 24) HIV patients receiving reverse-transcriptase inhibitors (tenofovir/ emtricitabine/ efavirenz and abacavir/ lamivudine/ efavirenz), group 2 (n = 22) HIV patients receiving protease inhibitors combined with other antiretroviral drugs (tenofovir/ emtricitabine with ritonavir/ atazanavir or lopinavir/ ritonavir, and darunavir/ ritonavir/ raltegravir), group 3 (n = 13) HIV ART-naïve patients, and group 4 (n = 8) healthy individuals (controls). Nuclear abnormalities in buccal mucosal samples (micronuclei, binucleated cells, nuclear buds, karyorrhexis, karyolysis, and pyknosis) were quantified. Simultaneously, blood samples were taken to quantify CD4+, CD8+, and HIV viral load. There was a significant age difference between HIV ART-naïve patients and receiving ART groups. Infection time was longer in HIV patients with ART than in ART-naïve patients. There were no differences in sex, smoking, alcohol consumption, or number of micronucleated cells between the study groups. We found higher frequencies of binucleated cells and nuclear buds in HIV patients, HIV ART-naïve, and HIV ART patients compared to the control group. We found a positive correlation between nuclear buds and CD4/CD8 ratio in the HIV ART-naïve group. In conclusion, PLWH showed increased genomic instability. The CD4/CD8 ratio affects the numbers of nuclear buds and binucleated cells. These findings are pertinent to mechanisms of damage and possible strategies to mitigate carcinogenesis in PLWH.
Subject(s)
Genomic Instability , HIV Infections/genetics , Adult , Anti-HIV Agents/adverse effects , Anti-HIV Agents/therapeutic use , CD4 Lymphocyte Count , CD4-CD8 Ratio , Female , Genomic Instability/drug effects , HIV/drug effects , HIV/physiology , HIV Infections/drug therapy , HIV Infections/immunology , HIV Infections/pathology , Humans , Male , Middle Aged , Reverse Transcriptase Inhibitors/adverse effects , Reverse Transcriptase Inhibitors/therapeutic use , Viral Load/drug effects , Viral Load/physiology , Young AdultABSTRACT
In the situation of radiation triage, accidental exposure to uranium, or uranium contamination in food or water; haematopoietic decline or bone marrow sickness is observed in the aftermath followed by other systemic effects. Most studies done previously have been on cytogenetic analysis in blood lymphocytes of uranium miners wherein causal relationship was difficult to be established. This study provides new insights into the minimum risk level of uranium to human lymphocytes, DNA damage induced and alterations in the cell cycle progression through 96-h acute toxicity study. Cytotoxicity studies by MTT assay and flow cytometry showed that uranyl nitrate concentration of 1280 µM lead to 50% cell death, 640 µM caused 25% death, 250 µM caused 10% cell death and 5 µM was the NOAEL. Uranium caused DNA damages in a dose dependent manner as evident from comet and CBMN assays. A marked increase in G2/M phase cells was observed in the test culture groups. Halting of cell cycle at G2/M checkpoint also signified the extent of double strand breaks and genetic instability with increasing uranium dose in this study. Better cell cycle responses and lower genetic damage index observed in lower dosage of exposure, suggests adaptability and repair responses in human lymphocytes. Together these results advance our understanding of uranium effects on mammalian cells.
Subject(s)
Lymphocytes/drug effects , Radioactive Pollutants/toxicity , Uranyl Nitrate/toxicity , Cell Cycle/drug effects , Cells, Cultured , Comet Assay , DNA Damage , Genomic Instability/drug effects , Humans , Micronucleus Tests , Toxicity Tests, Acute , UraniumABSTRACT
Cancer development is a multistep process that may be induced by a variety of compounds. Environmental substances, such as pesticides, have been associated with different human diseases. Organophosphorus pesticides (OPs) are among the most commonly used insecticides. Despite the fact that organophosphorus has been associated with an increased risk of cancer, particularly hormonemediated cancer, few prospective studies have examined the use of individual insecticides. Reported results have demonstrated that OPs and estrogen induce a cascade of events indicative of the transformation of human breast epithelial cells. In vitro studies analyzing an immortalized nontumorigenic human breast epithelial cell line may provide us with an approach to analyzing cell transformation under the effects of OPs in the presence of estrogen. The results suggested hormonemediated effects of these insecticides on the risk of cancer among women. It can be concluded that, through experimental models, the initiation of cancer can be studied by analyzing the steps that transform normal breast cells to malignant ones through certain substances, such as pesticides and estrogen. Such substances cause genomic instability, and therefore tumor formation in the animal, and signs of carcinogenesis in vitro. Cancer initiation has been associated with an increase in genomic instability, indicated by the inactivation of tumorsuppressor genes and activation of oncogenes in the presence of malathion, parathion, and estrogen. In the present study, a comprehensive summary of the impact of OPs in human and rat breast cancer, specifically their effects on the cell cycle, signaling pathways linked to epidermal growth factor, drug metabolism, and genomic instability in an MCF10F estrogen receptornegative breast cell line is provided.
Subject(s)
Breast Neoplasms/chemically induced , Breast/pathology , Cell Transformation, Neoplastic/chemically induced , Estrogens/metabolism , Insecticides/toxicity , Animals , Breast/cytology , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/pathology , Epithelial Cells , Female , Genomic Instability/drug effects , Humans , Malathion/toxicity , Parathion/toxicity , Rats , Signal Transduction/drug effectsABSTRACT
Activation of autophagy plays a critical role in DNA repair, especially for the process of homologous recombination. Despite upregulation of autophagy promotes both the survival and the death of cells, the pathways that govern the pro-cell death effects of autophagy are still incompletely understood. YM155 is originally developed as an expression suppressant of BIRC5 (an anti-apoptotic molecule) and it has reached Phase I/II clinical trials for the treatment of variety types of cancer. However, the target-specificity of YM155 has recently been challenged as several studies reported that YM155 exhibits direct DNA damaging effects. Recently, we discovered that BIRC5 is an autophagy negative-modulator. Using function-comparative analysis, we found in the current study that YM155 and BIRC5 siRNA both induced early "autophagy-dependent ROS production-mediated" DNA damage/strand breaks and concurrently downregulated the expression of RAD54L, RAD51, and MRE11, which are molecules known for their important roles in homologous recombination, in human cancer (MCF7, MDA-MB-231, and SK-BR-3) and mouse embryonic fibroblast (MEF) cells. Similar to the effects of YM155 and BIRC5 siRNA, downregulation of RAD54L and RAD51 by siRNA induced autophagy and DNA damage/strand breaks in cells, suggesting YM155/BIRC5 siRNA might also induce autophagy partly through RAD54L and RAD51 downregulations. We further observed that prolonged YM155 and BIRC5 siRNA treatment induced autophagic vesicle formation proximal to the nucleus and triggered DNA leakage. In conclusion, our findings reveal a novel mechanism of action of YM155 (i.e. induces autophagy-dependent ROS production-mediated DNA damage) in cancer cells and show the functional complexity of BIRC5 and autophagy involving the modulation of genome stability, highlighting that upregulation of autophagy is not always beneficial to the DNA repair process. Our findings can aid the development of a variety of BIRC5-directly/indirectly targeted anticancer therapies that are currently under pre-clinical and clinical investigations.
Subject(s)
Antineoplastic Agents/pharmacology , DNA Repair/drug effects , Genomic Instability/drug effects , Imidazoles/pharmacology , Naphthoquinones/pharmacology , Neoplasms/drug therapy , Survivin/genetics , Autophagy/drug effects , Cell Line, Tumor , Down-Regulation/drug effects , Humans , Neoplasms/genetics , Neoplasms/metabolism , Reactive Oxygen Species/metabolismABSTRACT
DNA helicases have risen to the forefront as genome caretakers. Their prominent roles in chromosomal stability are demonstrated by the linkage of mutations in helicase genes to hereditary disorders with defects in DNA repair, the replication stress response, and/or transcriptional activation. Conversely, accumulating evidence suggests that DNA helicases in cancer cells have a network of pathway interactions such that codeficiency of some helicases and their genetically interacting proteins results in synthetic lethality (SL). Such genetic interactions may potentially be exploited for cancer therapies. We discuss the roles of RECQ DNA helicases in cancer, emphasizing some of the more recent developments in SL.