-
Biochimica Et Biophysica Acta. Reviews... Dec 2021Temozolomide (TMZ) is a first-choice alkylating agent inducted as a gold standard therapy for glioblastoma multiforme (GBM) and astrocytoma. A majority of patients do... (Review)
Review
Temozolomide (TMZ) is a first-choice alkylating agent inducted as a gold standard therapy for glioblastoma multiforme (GBM) and astrocytoma. A majority of patients do not respond to TMZ during the course of their treatment. Activation of DNA repair pathways is the principal mechanism for this phenomenon that detaches TMZ-induced O-6-methylguanine adducts and restores genomic integrity. Current understanding in the domain of oncology adds several other novel mechanisms of resistance such as the involvement of miRNAs, drug efflux transporters, gap junction's activity, the advent of glioma stem cells as well as upregulation of cell survival autophagy. This review describes a multifaceted account of different mechanisms responsible for the intrinsic and acquired TMZ-resistance. Here, we summarize different strategies that intensify the TMZ effect such as MGMT inhibition, development of novel imidazotetrazine analog, and combination therapy; with an aim to incorporate a successful treatment and increased overall survival in GBM patients.
Topics: Antineoplastic Agents, Alkylating; Drug Resistance, Neoplasm; Glioblastoma; Glioma; Humans; Temozolomide
PubMed: 34419533
DOI: 10.1016/j.bbcan.2021.188616 -
Science (New York, N.Y.) Jul 2022Approximately half of glioblastoma and more than two-thirds of grade II and III glioma tumors lack the DNA repair protein O-methylguanine methyl transferase (MGMT)....
Approximately half of glioblastoma and more than two-thirds of grade II and III glioma tumors lack the DNA repair protein O-methylguanine methyl transferase (MGMT). MGMT-deficient tumors respond initially to the DNA methylation agent temozolomide (TMZ) but frequently acquire resistance through loss of the mismatch repair (MMR) pathway. We report the development of agents that overcome this resistance mechanism by inducing MMR-independent cell killing selectively in MGMT-silenced tumors. These agents deposit a dynamic DNA lesion that can be reversed by MGMT but slowly evolves into an interstrand cross-link in MGMT-deficient settings, resulting in MMR-independent cell death with low toxicity in vitro and in vivo. This discovery may lead to new treatments for gliomas and may represent a new paradigm for designing chemotherapeutics that exploit specific DNA repair defects.
Topics: Antineoplastic Agents, Alkylating; Brain Neoplasms; Cell Line, Tumor; DNA Methylation; DNA Modification Methylases; DNA Repair; DNA Repair Enzymes; Dacarbazine; Drug Design; Drug Resistance, Neoplasm; Glioblastoma; Humans; Temozolomide; Tumor Suppressor Proteins
PubMed: 35901163
DOI: 10.1126/science.abn7570 -
Neuro-oncology May 2023Temozolomide (TMZ) resistance has become an important obstacle affecting its therapeutic benefits. O6-methylguanine DNA methyltransferase (MGMT) is primarily responsible...
BACKGROUND
Temozolomide (TMZ) resistance has become an important obstacle affecting its therapeutic benefits. O6-methylguanine DNA methyltransferase (MGMT) is primarily responsible for the TMZ resistance in Glioblastoma multiforme (GBM) patients. In addition, active DNA damage repair pathways can also lead to TMZ resistance. Here, we reported a novel small-molecule inhibitor EPIC-0412 that improved the therapeutic efficacy of TMZ by inhibiting the DNA damage repair pathway and MGMT in GBM via epigenetic pathways.
METHODS
The small-molecule compound EPIC-0412 was obtained through high-throughput screening. RNA immunoprecipitation (RIP), chromatin isolation by RNA purification (ChIRP), and chromatin immunoprecipitation (ChIP) assays were used to verify the effect of EPIC-0412. Co-immunoprecipitation (Co-IP) was used to elucidate the interactions of transcription factors at the MGMT promoter region. Animal experiments using a mouse model were performed to verify the efficacy of EPIC-0412 in sensitizing GBM cells to TMZ.
RESULTS
EPIC-0412 physically interrupts the binding of HOTAIR and EZH2, leading to the upregulation of CDKN1A and BBC3, causing cell cycle arrest and apoptosis in GBM cells. EPIC-0412 inhibits DNA damage response in GBM cells through the p21-E2F1 DNA damage repair axis. EPIC-0412 epigenetically silences MGMT through its interaction with the ATF3-p-p65-HADC1 axis at the MGMT promoter region. The application of EPIC-0412 restored the TMZ sensitivity in GBM in vivo experiments.
CONCLUSION
This study discovered a small-molecule inhibitor EPIC-0412, which enhanced the chemotherapeutic effect of TMZ by acting on the p21-E2F1 DNA damage repair axis and ATF3-p-p65-MGMT axis, providing evidence for combining epigenetic drugs to increase the sensitization toward TMZ in GBM patients.
Topics: Animals; Temozolomide; Glioblastoma; Antineoplastic Agents, Alkylating; DNA Repair; DNA Repair Enzymes; Drug Resistance, Neoplasm; DNA Modification Methylases; RNA; Cell Line, Tumor
PubMed: 36272139
DOI: 10.1093/neuonc/noac242 -
Neuro-oncology Jul 2023Efficient DNA repair in response to standard chemo and radiation therapies often contributes to glioblastoma (GBM) therapy resistance. Understanding the mechanisms of...
BACKGROUND
Efficient DNA repair in response to standard chemo and radiation therapies often contributes to glioblastoma (GBM) therapy resistance. Understanding the mechanisms of therapy resistance and identifying the drugs that enhance the therapeutic efficacy of standard therapies may extend the survival of GBM patients. In this study, we investigated the role of KDM1A/LSD1 in DNA double-strand break (DSB) repair and a combination of KDM1A inhibitor and temozolomide (TMZ) in vitro and in vivo using patient-derived glioma stem cells (GSCs).
METHODS
Brain bioavailability of the KDM1A inhibitor (NCD38) was established using LS-MS/MS. The effect of a combination of KDM1A knockdown or inhibition with TMZ was studied using cell viability and self-renewal assays. Mechanistic studies were conducted using CUT&Tag-seq, RNA-seq, RT-qPCR, western blot, homologous recombination (HR) and non-homologous end joining (NHEJ) reporter, immunofluorescence, and comet assays. Orthotopic murine models were used to study efficacy in vivo.
RESULTS
TCGA analysis showed KDM1A is highly expressed in TMZ-treated GBM patients. Knockdown or knockout or inhibition of KDM1A enhanced TMZ efficacy in reducing the viability and self-renewal of GSCs. Pharmacokinetic studies established that NCD38 readily crosses the blood-brain barrier. CUT&Tag-seq studies showed that KDM1A is enriched at the promoters of DNA repair genes and RNA-seq studies confirmed that KDM1A inhibition reduced their expression. Knockdown or inhibition of KDM1A attenuated HR and NHEJ-mediated DNA repair capacity and enhanced TMZ-mediated DNA damage. A combination of KDM1A knockdown or inhibition and TMZ treatment significantly enhanced the survival of tumor-bearing mice.
CONCLUSIONS
Our results provide evidence that KDM1A inhibition sensitizes GBM to TMZ via attenuation of DNA DSB repair pathways.
Topics: Animals; Mice; Temozolomide; Glioblastoma; Lysine; DNA Breaks, Double-Stranded; Tandem Mass Spectrometry; Cell Line, Tumor; Glioma; DNA Repair; DNA; Histone Demethylases; Drug Resistance, Neoplasm; Antineoplastic Agents, Alkylating; Brain Neoplasms; Xenograft Model Antitumor Assays
PubMed: 36652263
DOI: 10.1093/neuonc/noad018 -
Cancer Discovery Jul 2022The majority of metastatic colorectal cancers (mCRC) are mismatch repair (MMR) proficient and unresponsive to immunotherapy, whereas MMR-deficient (MMRd) tumors often... (Clinical Trial)
Clinical Trial
UNLABELLED
The majority of metastatic colorectal cancers (mCRC) are mismatch repair (MMR) proficient and unresponsive to immunotherapy, whereas MMR-deficient (MMRd) tumors often respond to immune-checkpoint blockade. We previously reported that the treatment of colorectal cancer preclinical models with temozolomide (TMZ) leads to MMR deficiency, increased tumor mutational burden (TMB), and sensitization to immunotherapy. To clinically translate these findings, we designed the ARETHUSA clinical trial whereby O6-methylguanine-DNA-methyltransferase (MGMT)-deficient, MMR-proficient, RAS-mutant mCRC patients received priming therapy with TMZ. Analysis of tissue biopsies and circulating tumor DNA (ctDNA) revealed the emergence of a distinct mutational signature and increased TMB after TMZ treatment. Multiple alterations in the nucleotide context favored by the TMZ signature emerged in MMR genes, and the p.T1219I MSH6 variant was detected in ctDNA and tissue of 94% (16/17) of the cases. A subset of patients whose tumors displayed the MSH6 mutation, the TMZ mutational signature, and increased TMB achieved disease stabilization upon pembrolizumab treatment.
SIGNIFICANCE
MMR-proficient mCRCs are unresponsive to immunotherapy. We provide the proof of concept that inactivation of MMR genes can be achieved pharmacologically with TMZ and molecularly monitored in the tissue and blood of patients with mCRC. This strategy deserves additional evaluation in mCRC patients whose tumors are no longer responsive to standard-of-care treatments. See related commentary by Willis and Overman, p. 1612. This article is highlighted in the In This Issue feature, p. 1599.
Topics: Antineoplastic Agents, Alkylating; Brain Neoplasms; Cell Line, Tumor; Colorectal Neoplasms; DNA Mismatch Repair; DNA-Binding Proteins; Dacarbazine; Humans; Mutation; O(6)-Methylguanine-DNA Methyltransferase; Temozolomide
PubMed: 35522273
DOI: 10.1158/2159-8290.CD-21-1434 -
International Journal of Molecular... Feb 2023Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as... (Review)
Review
Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as impurities in various drugs. This is of particular concern as nitrosamines are alkylating agents that are genotoxic and carcinogenic. We first summarize the current knowledge on the different sources and chemical nature of alkylating agents with a focus on relevant nitrosamines. Subsequently, we present the major DNA alkylation adducts induced by nitrosamines upon their metabolic activation by CYP450 monooxygenases. We then describe the DNA repair pathways engaged by the various DNA alkylation adducts, which include base excision repair, direct damage reversal by MGMT and ALKBH, as well as nucleotide excision repair. Their roles in the protection against the genotoxic and carcinogenic effects of nitrosamines are highlighted. Finally, we address DNA translesion synthesis as a DNA damage tolerance mechanism relevant to DNA alkylation adducts.
Topics: Nitrosamines; DNA Damage; Alkylation; DNA Repair; Alkylating Agents; DNA Adducts
PubMed: 36902118
DOI: 10.3390/ijms24054684 -
Applied Microbiology and Biotechnology May 2023Alkylated bases in DNA created in the presence of endogenous and exogenous alkylating agents are either cytotoxic or mutagenic, or both to a cell. Currently, cells have... (Review)
Review
Alkylated bases in DNA created in the presence of endogenous and exogenous alkylating agents are either cytotoxic or mutagenic, or both to a cell. Currently, cells have evolved several strategies for repairing alkylated base. One strategy is a base excision repair process triggered by a specific DNA glycosylase that is used for the repair of the cytotoxic 3-methyladenine. Additionally, the cytotoxic and mutagenic O-methylguanine (O-meG) is corrected by O-methylguanine methyltransferase (MGMT) via directly transferring the methyl group in the lesion to a specific cysteine in this protein. Furthermore, oxidative DNA demethylation catalyzed by DNA dioxygenase is utilized for repairing the cytotoxic 3-methylcytosine (3-meC) and 1-methyladenine (1-meA) in a direct reversal manner. As the third domain of life, Archaea possess 3-methyladenine DNA glycosylase II (AlkA) and MGMT, but no DNA dioxygenase homologue responsible for oxidative demethylation. Herein, we summarize recent progress in structural and biochemical properties of archaeal AlkA and MGMT to gain a better understanding of archaeal DNA alkylation repair, focusing on similarities and differences between the proteins from different archaeal species and between these archaeal proteins and their bacterial and eukaryotic relatives. To our knowledge, it is the first review on archaeal DNA alkylation repair conducted by DNA glycosylase and methyltransferase. KEY POINTS: • Archaeal MGMT plays an essential role in the repair of O -meG • Archaeal AlkA can repair 3-meC and 1-meA.
Topics: Methyltransferases; DNA, Archaeal; Alkylation; DNA Glycosylases; DNA; Dioxygenases
PubMed: 37036526
DOI: 10.1007/s00253-023-12506-3 -
Journal of Oncology Practice Oct 2017Glioblastoma is the most common and most aggressive form of primary brain tumor in adults and contributes to high social and medical burden as a result of its incurable... (Review)
Review
Glioblastoma is the most common and most aggressive form of primary brain tumor in adults and contributes to high social and medical burden as a result of its incurable nature and significant neurologic morbidity. Despite ongoing research, there has not been improvement in survival in glioblastoma. This review discusses recent advances in clinically significant molecular profiling, including IDH mutation status and O-methylguanine-DNA methyltransferase ( MGMT) promoter methylation. We review updates in management of newly diagnosed and recurrent glioblastoma, as well as common difficulties in management, such as pseudoprogression and pseudoresponse. Ongoing translational research in targeted therapy and immunotherapy is briefly discussed.
Topics: Aftercare; Age Factors; Angiogenesis Inhibitors; Antineoplastic Agents, Alkylating; Bevacizumab; Brain Neoplasms; Chemoradiotherapy, Adjuvant; Chemotherapy, Adjuvant; Cranial Irradiation; Cytoreduction Surgical Procedures; DNA Methylation; DNA Modification Methylases; DNA Repair Enzymes; Dacarbazine; Glioblastoma; Humans; Isocitrate Dehydrogenase; Magnetic Resonance Imaging; Mutation; Neoplasm Recurrence, Local; Neurosurgical Procedures; Promoter Regions, Genetic; Radiotherapy, Adjuvant; Temozolomide; Tumor Suppressor Proteins
PubMed: 29020535
DOI: 10.1200/JOP.2017.025536 -
Methods in Molecular Biology (Clifton,... 2022On-DNA reductive amination (on-DNA aldehyde with amine building blocks) and alkylation (on-DNA amine with aldehyde building blocks) are robust ways to form C-N bond. The...
On-DNA reductive amination (on-DNA aldehyde with amine building blocks) and alkylation (on-DNA amine with aldehyde building blocks) are robust ways to form C-N bond. The large sets of commercially available aldehyde and amine building blocks make reductive amination and alkylation widely used in DEL synthesis.
Topics: Aldehydes; Alkylation; Amination; Amines; DNA
PubMed: 36083540
DOI: 10.1007/978-1-0716-2545-3_5 -
Journal of Clinical Oncology : Official... Aug 2018Purpose Both temozolomide (TMZ) and poly (ADP-ribose) polymerase (PARP) inhibitors are active in small-cell lung cancer (SCLC). This phase II, randomized, double-blind... (Randomized Controlled Trial)
Randomized Controlled Trial
Randomized, Double-Blind, Phase II Study of Temozolomide in Combination With Either Veliparib or Placebo in Patients With Relapsed-Sensitive or Refractory Small-Cell Lung Cancer.
Purpose Both temozolomide (TMZ) and poly (ADP-ribose) polymerase (PARP) inhibitors are active in small-cell lung cancer (SCLC). This phase II, randomized, double-blind study evaluated whether addition of the PARP inhibitor veliparib to TMZ improves 4-month progression-free survival (PFS). Patients and Methods A total of 104 patients with recurrent SCLC were randomly assigned 1:1 to oral veliparib or placebo 40 mg twice daily, days 1 to 7, and oral TMZ 150 to 200 mg/m/day, days 1 to 5, of a 28-day cycle until disease progression, unacceptable toxicity, or withdrawal of consent. Response was determined by imaging at weeks 4 and 8, and every 8 weeks thereafter. Improvement in PFS at 4 months was the primary end point. Secondary objectives included overall response rate (ORR), overall survival (OS), and safety and tolerability of veliparib with TMZ. Exploratory objectives included PARP-1 and SLFN11 immunohistochemical expression, MGMT promoter methylation, and circulating tumor cell quantification. Results No significant difference in 4-month PFS was noted between TMZ/veliparib (36%) and TMZ/placebo (27%; P = .19); median OS was also not improved significantly with TMZ/veliparib (8.2 months; 95% CI, 6.4 to 12.2 months; v 7.0 months; 95% CI, 5.3 to 9.5 months; P = .50). However, ORR was significantly higher in patients receiving TMZ/veliparib compared with TMZ/placebo (39% v 14%; P = .016). Grade 3/4 thrombocytopenia and neutropenia more commonly occurred with TMZ/veliparib: 50% versus 9% and 31% versus 7%, respectively. Significantly prolonged PFS (5.7 v 3.6 months; P = .009) and OS (12.2 v 7.5 months; P = .014) were observed in patients with SLFN11-positive tumors treated with TMZ/veliparib. Conclusion Four-month PFS and median OS did not differ between the two arms, whereas a significant improvement in ORR was observed with TMZ/veliparib. SLFN11 expression was associated with improved PFS and OS in patients receiving TMZ/veliparib, suggesting a promising biomarker of PARP-inhibitor sensitivity in SCLC.
Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Biomarkers, Tumor; DNA Methylation; DNA Modification Methylases; DNA Mutational Analysis; DNA Repair Enzymes; Double-Blind Method; Female; Humans; Immunohistochemistry; Lung Neoplasms; Male; Middle Aged; Neoplastic Cells, Circulating; Nuclear Proteins; Placebos; Poly (ADP-Ribose) Polymerase-1; Promoter Regions, Genetic; Small Cell Lung Carcinoma; Temozolomide; Tumor Suppressor Proteins
PubMed: 29906251
DOI: 10.1200/JCO.2018.77.7672