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Cells Oct 2023Sulfur mustard (SM) and its derivatives are potent genotoxic agents, which have been shown to trigger the activation of poly (ADP-ribose) polymerases (PARPs) and the...
Sulfur mustard (SM) and its derivatives are potent genotoxic agents, which have been shown to trigger the activation of poly (ADP-ribose) polymerases (PARPs) and the depletion of their substrate, nicotinamide adenine dinucleotide (NAD). NAD is an essential molecule involved in numerous cellular pathways, including genome integrity and DNA repair, and thus, NAD supplementation might be beneficial for mitigating mustard-induced (geno)toxicity. In this study, the role of NAD depletion and elevation in the genotoxic stress response to SM derivatives, i.e., the monofunctional agent 2-chloroethyl-ethyl sulfide (CEES) and the crosslinking agent mechlorethamine (HN2), was investigated with the use of NAD booster nicotinamide riboside (NR) and NAD synthesis inhibitor FK866. The effects were analyzed in immortalized human keratinocytes (HaCaT) or monocyte-like cell line THP-1. In HaCaT cells, NR supplementation, increased NAD levels, and elevated PAR response, however, did not affect ATP levels or DNA damage repair, nor did it attenuate long- and short-term cytotoxicities. On the other hand, the depletion of cellular NAD via FK866 sensitized HaCaT cells to genotoxic stress, particularly CEES exposure, whereas NR supplementation, by increasing cellular NAD levels, rescued the sensitizing FK866 effect. Intriguingly, in THP-1 cells, the NR-induced elevation of cellular NAD levels did attenuate toxicity of the mustard compounds, especially upon CEES exposure. Together, our results reveal that NAD is an important molecule in the pathomechanism of SM derivatives, exhibiting compound-specificity. Moreover, the cell line-dependent protective effects of NR are indicative of system-specificity of the application of this NAD booster.
Topics: Humans; Alkylating Agents; NAD; Protective Factors; Poly(ADP-ribose) Polymerases; DNA
PubMed: 37830610
DOI: 10.3390/cells12192396 -
Chembiochem : a European Journal of... May 2017The cationic porphyrin 5,10,15,20-tetrakis (diisopropyl-guanidine)-21H,23H-porphine (DIGPor) selectively binds to DNA containing O -methylguanine (O -MeG) and inhibits...
The cationic porphyrin 5,10,15,20-tetrakis (diisopropyl-guanidine)-21H,23H-porphine (DIGPor) selectively binds to DNA containing O -methylguanine (O -MeG) and inhibits the DNA repair enzyme O -methylguanine-DNA methyltransferase (MGMT). The O -MeG selectivity and MGMT inhibitory activity of DIGPor were improved by incorporating Zn into the porphyrin. The resulting metal complex (Zn-DIGPor) potentiated the activity of the DNA-alkylating drug temozolomide in an MGMT-expressing cell line. To the best of our knowledge, this is the first example of DNA-targeted MGMT inhibition.
Topics: Antineoplastic Agents, Alkylating; Apoptosis; Brain Neoplasms; DNA; DNA Modification Methylases; DNA Repair Enzymes; Dacarbazine; Glioma; Guanine; Humans; Temozolomide; Tumor Cells, Cultured; Tumor Suppressor Proteins
PubMed: 28177192
DOI: 10.1002/cbic.201600652 -
Journal For Immunotherapy of Cancer May 2020Temozolomide (TMZ) chemotherapy is a current standard of care for glioblastoma (GBM), however it has only extended overall survival by a few months. Because it also...
BACKGROUND
Temozolomide (TMZ) chemotherapy is a current standard of care for glioblastoma (GBM), however it has only extended overall survival by a few months. Because it also modulates the immune system, both beneficially and negatively, understanding how TMZ interacts with immunotherapeutics is important. Oncolytic herpes simplex virus (oHSV) is a new class of cancer therapeutic with both cytotoxic and immunostimulatory activities. Here, we examine the combination of TMZ and an oHSV encoding murine interleukin 12, G47Δ-mIL12, in a mouse immunocompetent GBM model generated from non-immunogenic 005 GBM stem-like cells (GSCs.
METHODS
We first investigated the cytotoxic effects of TMZ and/or G47Δ-IL12 treatments in vitro, and then the antitumor effects of combination therapy in vivo in orthotopically implanted 005 GSC-derived brain tumors. To improve TMZ sensitivity, O-methylguanine DNA methyltransferase (MGMT) was inhibited. The effects of TMZ on immune cells were evaluated by flow cytometery and immunohistochemistry.
RESULTS
The combination of TMZ+G47Δ-IL12 kills 005 GSCs in vitro better than single treatments. However, TMZ does not improve the survival of orthotopic tumor-bearing mice treated with G47Δ-IL12, but rather can abrogate the beneficial effects of G47Δ-IL12 when the two are given concurrently. TMZ negatively affects intratumor T cells and macrophages and splenocytes. Addition of MGMT inhibitor O-benzylguanine (O6-BG), an inactivating pseudosubstrate of MGMT, to TMZ improved survival, but the combination with G47Δ-IL12 did not overcome the antagonistic effects of TMZ treatment on oHSV therapy.
CONCLUSIONS
These results illustrate that chemotherapy can adversely affect oHSV immunovirotherapy. As TMZ is the standard of care for GBM, the timing of these combined therapies should be taken into consideration when planning oHSV clinical trials with chemotherapy for GBM.
Topics: Animals; Antineoplastic Agents, Alkylating; Brain Neoplasms; Glioblastoma; Humans; Mice; Oncolytic Virotherapy; Temozolomide
PubMed: 32457126
DOI: 10.1136/jitc-2019-000345 -
Nucleic Acids Research Oct 2015Alkylated DNA-protein alkyltransferases repair alkylated DNA bases, which are among the most common DNA lesions, and are evolutionary conserved, from prokaryotes to...
Alkylated DNA-protein alkyltransferases repair alkylated DNA bases, which are among the most common DNA lesions, and are evolutionary conserved, from prokaryotes to higher eukaryotes. The human ortholog, hAGT, is involved in resistance to alkylating chemotherapy drugs. We report here on the alkylated DNA-protein alkyltransferase, SsOGT, from an archaeal species living at high temperature, a condition that enhances the harmful effect of DNA alkylation. The exceptionally high stability of SsOGT gave us the unique opportunity to perform structural and biochemical analysis of a protein of this class in its post-reaction form. This analysis, along with those performed on SsOGT in its ligand-free and DNA-bound forms, provides insights in the structure-function relationships of the protein before, during and after DNA repair, suggesting a molecular basis for DNA recognition, catalytic activity and protein post-reaction fate, and giving hints on the mechanism of alkylation-induced inactivation of this class of proteins.
Topics: Alkyl and Aryl Transferases; Alkylation; Archaeal Proteins; DNA; DNA Repair; Enzyme Stability; Models, Molecular; Mutation; Structure-Activity Relationship; Sulfolobus solfataricus
PubMed: 26227971
DOI: 10.1093/nar/gkv774 -
Redox Biology May 2022Overproduction of reactive oxygen species (ROS) drives inflammation and mutagenesis. However, the role of the DNA damage response in immune responses remains largely...
Overproduction of reactive oxygen species (ROS) drives inflammation and mutagenesis. However, the role of the DNA damage response in immune responses remains largely unknown. Here we found that stabilization of the mismatch repair (MMR) protein MSH6 in response to alkylation damage requires interactions with the molybdopterin synthase associating complex (MPTAC) and Ada2a-containing histone acetyltransferase complex (ATAC). Furthermore, MSH6 promotes sterol biosynthesis via the mevalonate pathway in a MPTAC- and ATAC-dependent manner. MPTAC reduces the source of alkylating agents (ROS). Therefore, the association between MMR proteins, MPTAC, and ATAC promotes anti-inflammation response and reduces alkylating agents. The inflammatory responses measured by xanthine oxidase activity are elevated in Lymphoblastoid Cell Lines (LCLs) from some Fragile X-associated disorders (FXD) patients, suggesting that alkylating agents are increased in these FXD patients. However, MPTAC is disrupted in LCLs from some FXD patients. In LCLs from other FXD patients, interaction between MSH6 and ATAC was lost, destabilizing MSH6. Thus, impairment of MPTAC and ATAC may cause alkylation damage resistance in some FXD patients.
Topics: Alkylating Agents; Alkylation; DNA Damage; DNA Repair; DNA-Binding Proteins; Humans; Reactive Oxygen Species; Sterols
PubMed: 35189552
DOI: 10.1016/j.redox.2022.102270 -
Cells Apr 2022Glioblastoma is a highly aggressive, invasive and treatment-resistant tumour. The DNA damage response (DDR) provides tumour cells with enhanced ability to activate cell...
Glioblastoma is a highly aggressive, invasive and treatment-resistant tumour. The DNA damage response (DDR) provides tumour cells with enhanced ability to activate cell cycle arrest and repair treatment-induced DNA damage. We studied the expression of DDR, its relationship with standard treatment response and patient survival, and its activation after treatment. The transcriptomic profile of DDR pathways was characterised within a cohort of isocitrate dehydrogenase (IDH) wild-type glioblastoma from The Cancer Genome Atlas (TCGA) and 12 patient-derived glioblastoma cell lines. The relationship between DDR expression and patient survival and cell line response to temozolomide (TMZ) or radiation therapy (RT) was assessed. Finally, the expression of 84 DDR genes was examined in glioblastoma cells treated with TMZ and/or RT. Although distinct DDR cluster groups were apparent in the TCGA cohort and cell lines, no significant differences in OS and treatment response were observed. At the gene level, the high expression of , and independently associated with poor prognosis in glioblastoma patients. Finally, we observed a substantial upregulation of DDR genes after treatment with TMZ and/or RT, particularly in RT-treated glioblastoma cells, peaking within 24 h after treatment. Our results confirm the potential influence of DDR genes in patient outcome. The observation of DDR genes in response to TMZ and RT gives insight into the global response of DDR pathways after adjuvant treatment in glioblastoma, which may have utility in determining DDR targets for inhibition.
Topics: Antineoplastic Agents, Alkylating; DNA Damage; Glioblastoma; Humans; Temozolomide; Transcriptome
PubMed: 35406779
DOI: 10.3390/cells11071215 -
Journal of Controlled Release :... Oct 2022Temozolomide (TMZ), an imidazotetrazine, is a second-generation DNA alkylating agent used as a first-line treatment of glioblastoma multiforme (GBM). It was approved by... (Review)
Review
Temozolomide (TMZ), an imidazotetrazine, is a second-generation DNA alkylating agent used as a first-line treatment of glioblastoma multiforme (GBM). It was approved by FDA in 2005 and declared a blockbuster drug in 2008. Although TMZ has shown 100% oral bioavailability and crosses the blood-brain barrier effectively, however it suffers from limitations such as a short half-life (∼1.8 h), rapid metabolism, and lesser accumulation in the brain (∼10-20%). Additionally, development of chemoresistance has been associated with its use. Since it is a potential chemotherapeutic agent with an unmet medical need, advanced delivery strategies have been explored to overcome the associated limitations of TMZ. Nanocarriers including liposomes, solid lipid nanoparticles (SLNs), nanostructure lipid carriers (NLCs), and polymeric nanoparticles have demonstrated their ability to improve its circulation time, stability, tissue-specific accumulation, sustained release, and cellular uptake. Because of the appreciable water solubility of TMZ (∼5 mg/mL), the physical loading of TMZ in these nanocarriers is always challenging. Alternatively, the conjugation approach, wherein TMZ has been conjugated to polymers or small molecules, has been explored with improved outcomes in vitro and in vivo. This review emphasized the practical evidence of the conjugation strategy to improve the therapeutic potential of TMZ in the treatment of glioblastoma multiforme.
Topics: Alkylating Agents; Antineoplastic Agents, Alkylating; Brain Neoplasms; Cell Line, Tumor; Delayed-Action Preparations; Drug Resistance, Neoplasm; Glioblastoma; Humans; Lipids; Liposomes; Nanoparticles; Polymers; Temozolomide; Water
PubMed: 35985493
DOI: 10.1016/j.jconrel.2022.08.024 -
Biochimica Et Biophysica Acta.... Jun 2022PIMREG expression strongly correlates with cellular proliferation in both malignant and normal cells. Throughout embryo development, PIMREG expression is prominent in...
PIMREG expression strongly correlates with cellular proliferation in both malignant and normal cells. Throughout embryo development, PIMREG expression is prominent in the central nervous system. Recent studies have described elevated PIMREG expression in different types of tumors, which correlates with patient survival and tumor aggressiveness. Given the emerging significance of PIMREG in carcinogenesis and its putative role in the context of the nervous system, we investigated the expression and function of PIMREG in gliomas, the most common primary brain tumors. We performed an extensive analysis of PIMREG expression in tumors samples from glioma patients. We then assessed the effects of PIMREG silencing and overexpression on the sensitivity of glioblastoma cell lines treated with genotoxic agents commonly used for treating patients and assessed for treatment response, proliferation and migration. Our analysis shows that glioblastoma exhibits the highest levels of PIMREG expression among all cancers analyzed and that elevated PIMREG expression is a biomarker for glioma progression and patient outcome. Moreover, PIMREG is induced by genotoxic agents, and its silencing renders glioblastoma cells sensitive to temozolomide treatment and affects ATR- and ATM-dependent signaling. Our data demonstrate that PIMREG is involved in DNA damage response and temozolomide resistance of glioblastoma cells and further supports a role for PIMREG in tumorigenesis.
Topics: Antineoplastic Agents, Alkylating; Cell Line, Tumor; DNA Damage; Glioblastoma; Humans; Temozolomide
PubMed: 35301087
DOI: 10.1016/j.bbadis.2022.166382 -
DNA Repair Mar 2023Alkylating agents are genotoxic chemicals that can induce and treat various types of cancer. This occurs through covalent bonding with cellular macromolecules, in... (Review)
Review
Alkylating agents are genotoxic chemicals that can induce and treat various types of cancer. This occurs through covalent bonding with cellular macromolecules, in particular DNA, leading to the loss of functional integrity under the persistence of modifications upon replication. O-alkylguanine (O-AlkylG) adducts are proposed to be the most potent DNA lesions induced by alkylating agents. If not repaired correctly, these adducts can result, at the molecular level, in DNA point mutations, chromosome aberrations, recombination, crosslinking, and single- and double-strand breaks (SSB/DSBs). At the cellular level, these lesions can result in malignant transformation, senescence, or cell death. O-methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein capable of removing the alkyl groups from O-AlkylG adducts in a damage reversal process that can prevent the adverse biological effects of DNA damage caused by guanine O-alkylation. MGMT can thereby defend normal cells against tumor initiation, however it can also protect tumor cells against the beneficial effects of chemotherapy. Hence, MGMT can play an important role in both the prevention and treatment of cancer; thus, it can be considered as a double-edged sword. From a clinical perspective, MGMT is a therapeutic target, and it is important to explore the rational development of its clinical exploitation.
Topics: Humans; Alkylating Agents; DNA; DNA Damage; DNA Modification Methylases; DNA Repair; DNA Repair Enzymes; Neoplasms; O(6)-Methylguanine-DNA Methyltransferase; Tumor Suppressor Proteins
PubMed: 36680944
DOI: 10.1016/j.dnarep.2023.103449 -
The Journal of Biological Chemistry Jun 2018Endogenous metabolism, environmental exposure, and cancer chemotherapy can lead to alkylation of DNA. It has been well documented that, among the different DNA...
Endogenous metabolism, environmental exposure, and cancer chemotherapy can lead to alkylation of DNA. It has been well documented that, among the different DNA alkylation products, minor-groove -alkylthymidine (-alkyldT) lesions are inefficiently repaired. In the present study, we examined how seven -alkyldT lesions, with the alkyl group being a Me, Et, Pr, Pr, Bu, Bu, or Bu, are recognized by the DNA replication machinery in human cells. We found that the replication bypass efficiencies of these lesions decrease with increasing length of the alkyl chain, and that these lesions induce substantial frequencies of T→A and T→G mutations. Replication experiments using isogenic cells deficient in specific translesion synthesis (TLS) DNA polymerases revealed that the absence of polymerase η or polymerase ζ, but not polymerase κ or polymerase ι, significantly decreased both the bypass efficiencies and the mutation frequencies for those -alkyldT lesions carrying a straight-chain alkyl group. Moreover, the mutagenic properties of the -alkyldT lesions were influenced by the length and topology of the alkyl chain and by TLS polymerases. Together, our results provide important new knowledge about the cytotoxic and mutagenic properties of -alkyldT lesions, and illustrate the roles of TLS polymerases in replicative bypass of these lesions in human cells.
Topics: Alkylation; CRISPR-Cas Systems; DNA; DNA Damage; DNA Replication; DNA-Directed DNA Polymerase; Gene Editing; HEK293 Cells; Humans; Mutagenesis; Thymidine
PubMed: 29685891
DOI: 10.1074/jbc.RA118.003133