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Waters MD, Warren S, Hughes C, Lewis P, Zhang F. Human genetic risk of treatment with antiviral nucleoside analog drugs that induce lethal mutagenesis: The special case of molnupiravir. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2022; 63:37-63. [PMID: 35023215 DOI: 10.1002/em.22471] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/28/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
This review considers antiviral nucleoside analog drugs, including ribavirin, favipiravir, and molnupiravir, which induce genome error catastrophe in SARS-CoV or SARS-CoV-2 via lethal mutagenesis as a mode of action. In vitro data indicate that molnupiravir may be 100 times more potent as an antiviral agent than ribavirin or favipiravir. Molnupiravir has recently demonstrated efficacy in a phase 3 clinical trial. Because of its anticipated global use, its relative potency, and the reported in vitro "host" cell mutagenicity of its active principle, β-d-N4-hydroxycytidine, we have reviewed the development of molnupiravir and its genotoxicity safety evaluation, as well as the genotoxicity profiles of three congeners, that is, ribavirin, favipiravir, and 5-(2-chloroethyl)-2'-deoxyuridine. We consider the potential genetic risks of molnupiravir on the basis of all available information and focus on the need for additional human genotoxicity data and follow-up in patients treated with molnupiravir and similar drugs. Such human data are especially relevant for antiviral NAs that have the potential of permanently modifying the genomes of treated patients and/or causing human teratogenicity or embryotoxicity. We conclude that the results of preclinical genotoxicity studies and phase 1 human clinical safety, tolerability, and pharmacokinetics are critical components of drug safety assessments and sentinels of unanticipated adverse health effects. We provide our rationale for performing more thorough genotoxicity testing prior to and within phase 1 clinical trials, including human PIG-A and error corrected next generation sequencing (duplex sequencing) studies in DNA and mitochondrial DNA of patients treated with antiviral NAs that induce genome error catastrophe via lethal mutagenesis.
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Affiliation(s)
- Michael D Waters
- Michael Waters Consulting USA, Hillsborough, North Carolina, USA
| | | | - Claude Hughes
- Duke University Medical Center, Durham, North Carolina, USA
| | | | - Fengyu Zhang
- Global Clinical and Translational Research Institute, Bethesda, Maryland, USA
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Antiretroviral Therapy Initiation Alters the Redox System of Asymptomatic HIV-Infected Individuals: A Longitudinal Study. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:9834803. [PMID: 28421130 PMCID: PMC5379093 DOI: 10.1155/2017/9834803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 02/15/2017] [Accepted: 02/20/2017] [Indexed: 01/11/2023]
Abstract
Background. The combination antiretroviral therapy (cART) increases the oxidative stress in HIV-infected people, which in turn favors the onset and aggravation of non-AIDS comorbidities, a common situation affecting these individuals. We aimed to evaluate the influence of cART initiation on oxidative stress parameters. This is a longitudinal study including 30 asymptomatic patients divided according to their CD4+ T cell count (G1: <500 cell/mL; G2: >500 cell/mL) before (M0) and after (M1) cART initiation. We analyzed total antioxidant capacity (TAC), fat-soluble vitamins, malondialdehyde, 8-isoprostane, and DNA damage. Results. Results showed a decrease in TAC, retinol, α-tocopherol, and some carotenoids, in addition to a significant increase in DNA damage at M1. These changes were more evident in G2 subjects. Moreover, there was a significant 8-isoprostane increase at M1 in individuals belonging to G1. Conclusion. The results indicate that cART interfered in the redox system, mainly by reducing the antioxidant defenses. In addition, patients who had CD4+ T counts higher than 500 cells/mm3 showed more susceptibility to genotoxicity, while patients with less CD4+ T counts displayed more damage triggered by lipoperoxidation. Considering the early beginning of cART, its chronic use, and its capacity to alter the redox status, further long-term studies on larger cohorts are needed to define the best time to initiate therapy and to investigate new strategies to delay the development of non-AIDS diseases.
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Pediatric Human Immunodeficiency Virus infection and cancer in the Highly Active Antiretroviral Treatment (HAART) era. Cancer Lett 2014; 347:38-45. [DOI: 10.1016/j.canlet.2014.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/13/2014] [Accepted: 02/03/2014] [Indexed: 12/18/2022]
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Noguera Julian A, De José MI. [Recommendations issued by the Spanish Society of Pediatric Infectious Diseases for the follow-up of the child exposed to the human immunodeficiency virus and to antiretroviral drugs during pregnancy and the neonatal period]. An Pediatr (Barc) 2012; 76:360.e1-9. [PMID: 22406157 DOI: 10.1016/j.anpedi.2012.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/05/2012] [Indexed: 10/28/2022] Open
Abstract
Human immunodeficiency virus vertical transmission in developed countries has dramatically decreased to less than 2% over the last 15 years due to the consecutive implementation of different prophylactic measures, including the use of antiretrovirals, elective cesarean section and refraining from breastfeeding. The follow-up of these otherwise healthy children is, by far, the most common situation related to HIV infection that general pediatricians currently face in routine clinical care in Spain. These recommendations issued by the Spanish Society of Pediatric Infectious Diseases attempt to summarize the main aspects of this follow-up, including birth management, type of feeding, neonatal antiretroviral prophylaxis, HIV infection diagnosis, common early comorbidities, short- and mid-term toxicities, vaccination and other prophylactic measures and long-term follow-up.
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Affiliation(s)
- A Noguera Julian
- Unitat d'Infectologia, Servei de Pediatria, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain.
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Liu Y, Nguyen P, Baris TZ, Poirier MC. Molecular Analysis of Mitochondrial Compromise in Rodent Cardiomyocytes Exposed Long Term to Nucleoside Reverse Transcriptase Inhibitors (NRTIs). Cardiovasc Toxicol 2011; 12:123-34. [DOI: 10.1007/s12012-011-9148-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Ross AC, Leong T, Avery A, Castillo-Duran M, Bonilla H, Lebrecht D, Walker UA, Storer N, Labbato D, Khaitan A, Tomanova-Soltys I, McComsey GA. Effects of in utero antiretroviral exposure on mitochondrial DNA levels, mitochondrial function and oxidative stress. HIV Med 2011; 13:98-106. [PMID: 22103263 DOI: 10.1111/j.1468-1293.2011.00945.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES HIV and antiretroviral (ART) exposure in utero may have deleterious effects on the infant, but uncertainty still exists. The objective of this study was to evaluate aspects of mitochondrial DNA (mtDNA) content, mitochondrial function and oxidative stress simultaneously in placenta, umbilical cord blood and infant blood in HIV/ART-exposed infants compared with uninfected controls. METHODS HIV-1-infected pregnant women and HIV-1-uninfected healthy pregnant controls were enrolled in the study prospectively. Placenta and umbilical cord blood were obtained at delivery and infant blood was obtained within 48 h of delivery. mtDNA content was determined for each specimen. Nuclear [subunit IV of cytochrome c-oxidase (COX IV)]- and mitochondrial (COX II)-encoded polypeptides of the oxidative phosphorylation enzyme cytochrome c-oxidase were quantified in cord and infant blood. Placental mitochondria malondialdehyde (MDA) concentrations were measured as a marker of oxidative stress. RESULTS Twenty HIV-positive/HIV-exposed and 26 control mother-infant pairs were enrolled in the study. All HIV-infected women and their infants received ART. Placental MDA concentration and mtDNA content in placenta and cord blood were similar between groups. The cord blood COX II:IV ratio was lower in the HIV-positive group than in the controls, whereas the infant peripheral blood mtDNA content was higher in the HIV-exposed infants, but the infant peripheral blood COX II:IV ratio was similar. No infant had clinical evidence of mitochondrial disease or acquired HIV infection. In multivariable regression analyses, the significant findings in cord and infant blood were both most associated with HIV/ART exposure. CONCLUSIONS HIV-exposed infants showed reduced umbilical cord blood mitochondrial enzyme expression with increased infant peripheral blood mitochondrial DNA levels, the latter possibly reflecting a compensatory mechanism to overcome HIV/ART-associated mitochondrial toxicity.
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Affiliation(s)
- A C Ross
- Emory University School of Medicine, Atlanta, GA, USA.
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Guimarães NN, de Andrade HHR, Lehmann M, Dihl RR, Cunha KS. The genetic toxicity effects of lamivudine and stavudine antiretroviral agents. Expert Opin Drug Saf 2011; 9:771-81. [PMID: 20377473 DOI: 10.1517/14740331003702384] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
IMPORTANCE OF THE FIELD The nucleoside reverse transcriptase inhibitors (NRTIs) are used in antiretroviral therapy worldwide for the treatment of HIV infections. These drugs act by blocking reverse transcriptase enzyme activity, causing pro-viral DNA chain termination. As a consequence, NRTIs could cause genomic instability and loss of heterozygosity. AREAS COVERED IN THIS REVIEW This review highlights the toxic and genotoxic effects of NRTIs, particularly lamivudine (3TC) and stavudine (d4T) analogues. In addition, a battery of short-term in vitro and in vivo systems are described to explain the potential genotoxic effects of these NRTIs as a single drug or a complexity of highly active antiretroviral therapy. WHAT THE READER WILL GAIN The readers will gain an understanding of a secondary effect that could be induced by 3TC and d4T treatments. TAKE HOME MESSAGE Considering that AIDS has become a chronic disease, more comprehensive toxic genetic studies are needed, with particular attention to the genetic alterations induced by NRTIs. These alterations play a primary role in carcinogenesis and are also involved in secondary and subsequent steps of carcinogenesis.
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Affiliation(s)
- Nilza Nascimento Guimarães
- Laboratório de Genética Toxicológica, Departamento de Bioquímica e Biologia Molecular (DBBM), Instituto de Ciências Biológicas (ICB), Universidade Federal de Goiás (UFG), Goiânia, GO, Brasil
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Abstract
PURPOSE OF REVIEW This review summarizes recent developments regarding the unique clinical pharmacologic profile of nucleoside analog reverse transcriptase inhibitors for management of HIV. RECENT FINDINGS First, intracellular data in patients suggest that nucleoside reverse transcriptase inhibitor-triphosphates are compartmentalized in different cell types. Additionally, intracellular drug-drug interactions were identified, which were undetectable in plasma. Second, extracellular data illustrate multiple bidirectional plasma drug-drug interactions between renally eliminated tenofovir and liver-metabolized drugs. Definitive mechanistic details for these interactions are lacking but they appear to involve renal and/or enteric drug transporters. Furthermore, the plasma versus female genital tract disposition of these agents was recently elucidated, which is important for currently investigated indications for pre-exposure and post-exposure prophylaxis. Finally, tenofovir/emtricitabine and abacavir (using a promising human leukocyte antigen-B*5701 genetic test for hypersensitivity)/lamivudine have emerged as common first-line nucleoside analog reverse transcriptase inhibitors because of co-formulations, once-daily dosing, and favorable tolerability and adverse effect profiles. Nevertheless, elucidating the long-term safety profile for all nucleoside analog reverse transcriptase inhibitors remains a priority. SUMMARY Knowledge of nucleoside analog reverse transcriptase inhibitor disposition intracellularly and extracellularly has expanded. This provides a basis for rational use of these agents clinically and adds new perspectives for future research.
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Walker DM, Kajon AE, Torres SM, Carter MM, McCash CL, Swenberg JA, Upton PB, Hardy AW, Olivero OA, Shearer GM, Poirier MC, Walker VE. WR1065 mitigates AZT-ddI-induced mutagenesis and inhibits viral replication. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:460-72. [PMID: 19334055 PMCID: PMC3197270 DOI: 10.1002/em.20482] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The success of nucleoside reverse transcriptase inhibitors (NRTIs) in treating HIV-1 infection and reducing mother-to-child transmission of the virus during pregnancy is accompanied by evidence that NRTIs cause long-term health risks for cancer and mitochondrial disease. Thus, agents that mitigate toxicities of the current combination drug therapies are needed. Previous work had shown that the NRTI-drug pair zidovudine (AZT)-didanosine (ddI) was highly cytotoxic and mutagenic; thus, we conducted preliminary studies to investigate the ability of the active moiety of amifostine, WR1065, to protect against the deleterious effects of this NRTI-drug pair. In TK6 cells exposed to 100 muM AZT-ddI (equimolar) for 3 days with or without 150 muM WR1065, WR1065 enhanced long-term cell survival and significantly reduced AZT-ddI-induced mutations. Follow-up studies were conducted to determine if coexposure to AZT and WR1065 abrogated the antiretroviral efficacy of AZT. In human T-cell blasts infected with HIV-1 in culture, inhibition of p24 protein production was observed in cells treated with 10 muM AZT in the absence or presence of 5-1,000 muM WR1065. Surprisingly, WR1065 alone exhibited dose-related inhibition of HIV-1 p24 protein production. WR1065 also had antiviral efficacy against three species of adenovirus and influenza A and B. Intracellular levels of unbound WR1065 were measured following in vitro/in vivo drug exposure. These pilot study results indicate that WR1065, at low intracellular levels, has cytoprotective and antimutagenic activities against the most mutagenic pair of NRTIs and has broad spectrum antiviral effects. These findings suggest that the activities have a possible common mode of action that merits further investigation.
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Affiliation(s)
- Dale M. Walker
- BioMosaics, Inc., Burlington, Vermont
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Adriana E. Kajon
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Salina M. Torres
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
- College of Pharmacy, University of New Mexico, Albuquerque, New Mexico
| | - Meghan M. Carter
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | | | - James A. Swenberg
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Patricia B. Upton
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Andrew W. Hardy
- AMRV, CCR, National Cancer Institute, NIH, Bethesda, Maryland
| | - Ofelia A. Olivero
- CDI Section, LCBG, CCR, National Cancer Institute, NIH, Bethesda, Maryland
| | - Gene M. Shearer
- AMRV, CCR, National Cancer Institute, NIH, Bethesda, Maryland
| | - Miriam C. Poirier
- CDI Section, LCBG, CCR, National Cancer Institute, NIH, Bethesda, Maryland
| | - Vernon E. Walker
- BioMosaics, Inc., Burlington, Vermont
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
- College of Pharmacy, University of New Mexico, Albuquerque, New Mexico
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Fang JL, Beland FA. Long-term exposure to zidovudine delays cell cycle progression, induces apoptosis, and decreases telomerase activity in human hepatocytes. Toxicol Sci 2009; 111:120-30. [PMID: 19541796 DOI: 10.1093/toxsci/kfp136] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Zidovudine (3'-azido-3'-deoxythymidine; AZT), which is currently used in the treatment of acquired immunodeficiency syndrome, has been shown to have anticancer properties. In the present study, we examined the mechanisms contributing to increased sensitivity of cancer cells to the growth-inhibitory effects of AZT. This was accomplished by incubating a hepatoma cell line (HepG2) and a normal liver cell line (THLE2) with AZT in continuous culture for up to 4 weeks and evaluating the number of viable and necrotic cells, the induction of apoptosis, cell cycle alterations, and telomerase activity. In HepG2 cells, AZT (2-100 microM) caused significant dose-dependent decreases in the number of viable cells at exposures > 24 h. During a 1-week recover period, there was only a slight increase in the number of viable cells treated with AZT. The decrease in viable cells was associated with an induction of apoptosis, a decrease in telomerase activity, and S and G2/M phase arrest of the cell cycle. During the recovery period, the extent of apoptosis and telomerase activity returned to control levels, whereas the disruption of cell cycle progression persisted. Western blot analysis indicated that AZT caused a decrease in checkpoint kinase 1 (Chk1) and kinase 2 (Chk2) and an increase in phosphorylated Chk1 (Ser345) and Chk2 (Thr68). Similar effects, to lesser extent, were observed in THLE2 cells given much higher concentrations of AZT (50-2500 microM). These data show that HepG2 cells are much more sensitive than THLE2 cells to AZT. They also indicate that a combination of a delay of cell cycle progression, an induction of apoptosis, and a decrease in telomerase activity is contributing to the decrease in the number of viable cells from AZT treatment, and that checkpoint enzymes Chk1 and Chk2 may play an important role in the delay of cell cycle progression.
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Affiliation(s)
- Jia-Long Fang
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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Mutagenic and recombinagenic effects of lamivudine and stavudine antiretrovirals in somatic cells of Drosophila melanogaster. Food Chem Toxicol 2009; 47:578-82. [DOI: 10.1016/j.fct.2008.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 11/18/2008] [Accepted: 12/15/2008] [Indexed: 11/21/2022]
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Torres SM, Walker DM, McCash CL, Carter MM, Ming J, Cordova EM, Pons RM, Cook DL, Seilkop SK, Copeland WC, Walker VE. Mutational analysis of the mitochondrial tRNA genes and flanking regions in umbilical cord tissue from uninfected infants receiving AZT-based therapies for prophylaxis of HIV-1. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:10-26. [PMID: 19031409 PMCID: PMC3191876 DOI: 10.1002/em.20433] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A sensitive vertical denaturing gradient gel electrophoresis (DGGE) method, using 13 unipolar psoralen-clamped PCR primer pairs, was developed for detecting sequence variants in the 22 tRNA genes and flanking regions (together spanning approximately 21%) of the human mitochondrial genome. A study was conducted to determine (i) if mitochondrial DNA (mtDNA) polymorphisms and/or mutations were detectable in healthy newborns and (ii) if prepartum 3'-azido-2',3'-dideoxythymidine (AZT) based HIV-1 prophylaxis was associated with significant increases in mtDNA mutations and changes in the degree of heteroplasmy of sequence variants in uninfected infants born to HIV-1-infected mothers. DGGE analysis of umbilical cord tissue (where vascular endothelium and smooth muscle cells are the major source of mtDNA) showed that mtDNA sequence variants were significantly elevated by threefold in AZT-treated infants compared with unexposed controls (P < 0.001), with 24 changes observed in 19/52 (37%) treated newborns (averaging 0.46 changes/subject) versus only eight changes found in 7/55 (13%) unexposed newborns (averaging 0.15 changes/subject). Six distinct sequence variants occurring in unexposed controls were predominately synonymous and homoplasmic, representing previously reported polymorphisms. Uninfected infants exposed to a combination of AZT and 2',3'-dideoxy-3'-thiacytidine and "maternal HIV-1" had a significant shift in the spectrum of mutations (P = 0.04) driven by increases in nonsynonymous heteroplasmic sequence variants at polymorphic sites (10 distinct variants) and novel sites (four distinct variants). While the weight of evidence suggests that prepartum AZT-based prophylaxis produces mtDNA mutations, additional research is needed to determine the degree to which fetal responses to maternal HIV-1 infection, in the absence of antiretroviral treatment, contribute to prenatal mtDNA mutagenesis.
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Affiliation(s)
- Salina M. Torres
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Dale M. Walker
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
- BioMosaics, Inc., Burlington, Vermont
| | | | - Meghan M. Carter
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Jessica Ming
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | | | - Rachel M. Pons
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Dennis L. Cook
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | | | - William C. Copeland
- Laboratory of Molecular Genetics, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina
| | - Vernon E. Walker
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
- BioMosaics, Inc., Burlington, Vermont
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Kline ER, Bassit L, Hernandez-Santiago BI, Detorio MA, Liang B, Kleinhenz DJ, Walp ER, Dikalov S, Jones DP, Schinazi RF, Sutliff RL. Long-term exposure to AZT, but not d4T, increases endothelial cell oxidative stress and mitochondrial dysfunction. Cardiovasc Toxicol 2008; 9:1-12. [PMID: 19067249 DOI: 10.1007/s12012-008-9029-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 11/18/2008] [Indexed: 12/01/2022]
Abstract
Nucleoside reverse transcriptase inhibitors (NRTIs), such as zidovudine (AZT) and stavudine (d4T), cause toxicities to numerous tissues, including the liver and vasculature. While much is known about hepatic NRTI toxicity, the mechanism of toxicity in endothelial cells is incompletely understood. Human aortic endothelial and HepG2 liver cells were exposed to 1 muM AZT or d4T for up to 5 weeks. Markers of oxidative stress, mitochondrial function, NRTI phosphorylation, mitochondrial DNA (mtDNA) levels, and cytotoxicity were monitored over time. In endothelial cells, AZT significantly oxidized glutathione redox potential, increased total cellular and mitochondrial-specific superoxide, decreased mitochondrial membrane potential, increased lactate release, and caused cell death from weeks 3 through 5. Toxicity occurred in the absence of di- and tri-phosphorylated AZT and mtDNA depletion. These data show that oxidative stress and mitochondrial dysfunction in endothelial cells occur with a physiologically relevant concentration of AZT, and require long-term exposure to develop. In contrast, d4T did not induce endothelial oxidative stress, mitochondrial dysfunction, or cytotoxicity despite the presence of d4T-triphosphate. Both drugs depleted mtDNA in HepG2 cells without causing cell death. Endothelial cells are more susceptible to AZT-induced toxicity than HepG2 cells, and AZT caused greater endothelial dysfunction than d4T because of its pro-oxidative effects.
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Affiliation(s)
- Erik R Kline
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University School of Medicine/Atlanta VA Medical Center, Atlanta, GA 30033, USA
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Koujitani T, Ton TVT, Lahousse SA, Hong HHL, Wakamatsu N, Sills RC. K-ras cancer gene mutations in lung tumors from female Swiss (CD-1) mice exposed transplacentally to 3'-azido-3'-deoxythymidine. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:720-726. [PMID: 18800350 DOI: 10.1002/em.20420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A transplacental carcinogenicity study was conducted by exposing pregnant Swiss (CD-1) mice to 0, 50, 100, 200, or 300 mg 3'-azido-3'-deoxythymidine (AZT)/kg body weight (BW) daily for the duration of gestation (18-19 days) [National Toxicology Program,2006]. The incidence of alveolar/bronchiolar adenomas and carcinomas in the 200 and 300 mg/kg groups was significantly higher (P = 0.027 and 0.007, respectively) in male offspring, but not in females (P = 0.338 and 0.315, respectively). The purpose of the present study was to evaluate K-ras mutation status in lung tumors from the female offspring in AZT exposed groups and to determine whether at the molecular level there were signature K-ras mutations in lung tumors that were different from spontaneous tumors. K-ras mutation was detected by cycle sequencing of polymerase chain reaction (PCR)-amplified DNA, isolated from formalin-fixed, paraffin-embedded lung tumors. K-ras mutations were detected in 17 of 28 (61%) lung tumors from the female offspring in AZT exposed groups. No K-ras mutations were detected in the 8 tumors examined from the female control group. The predominant mutations were Codon 12 G-->T transversions in the 50, 100, and 300 mg/kg groups, and Codon 12 G-->C transversions in the 200 and 300 mg/kg groups. K-ras Codon 12 G-->T transversions (TGT mutations) may be induced by oxidative DNA damage and 8-oxoguanine (8-oxoG), while K-ras Codon 12 G-->C transversions (CGT mutations) may be due to further oxidative lesions of guanine and 8-oxoG.
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Affiliation(s)
- Takatoshi Koujitani
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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Valentine CR, Rainey HF, Farrell JM, Shaddock JG, Dobrovolsky VN, Delongchamp RR. Frequency and spectrum of ENU-induced mutation in the X174 transgene in mouse splenic lymphocytes and their significance to spontaneous transgenic rodent mutation frequencies. Mutagenesis 2008; 23:383-97. [DOI: 10.1093/mutage/gen026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Bayram S, Topaktaş M. Confirmation of the chromosome damaging effects of lamivudine in in vitro human peripheral blood lymphocytes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:328-333. [PMID: 18366100 DOI: 10.1002/em.20393] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The aim of this study was to investigate genotoxic effects of lamivudine (an analogue of cytidine) using in vitro sister chromatid exchange (SCE), chromosome aberration (CA), and micronucleus (MN) tests in human peripheral lymphocytes. The cells were treated with 75, 100, 125, and 150 microg/ml concentrations of lamivudine (roughly 30-60 times higher than plasma levels achieved in patients receiving this drug) for two (24- and 48-hr) treatment periods. Lamivudine induced SCEs at the highest concentration (150 microg/ml) in the 24-hr treatment, and at 125 and 150 microg/ml in the 48-hr treatment, when compared to the solvent control. During both treatment periods, structural chromosome aberrations were significantly increased at 100, 125, and 150 microg/ml lamivudine concentrations. However, the increases of SCEs (22%) and CAs (50%) were weak. In addition, lamivudine reduced both the proliferation index (PI) and the mitotic index (MI) significantly at all concentrations for the two treatment periods. The MI was reduced by lamivudine in a dose-dependent manner during both the 24- and 48-hr treatment periods. In contrast, the PI was reduced by lamivudine only during the 48-hr treatment period. A weak but significant increase in MN formation was observed following lamivudine treatment at 100, 125, and 150 microg/ml for 48 hr, but no significant increase in micronuclei were observed following 24-hr treatment. In conclusion, lamivudine has a weak genotoxic effect at elevated doses on human peripheral lymphocytes.
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Affiliation(s)
- Süleyman Bayram
- Department of Biology, Natural and Applied Science Institute, Cukurova University, Adana, Turkey
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Nucleoside reverse transcriptase inhibitors (NRTIs)-induced expression profile of mitochondria-related genes in the mouse liver. Mitochondrion 2008; 8:181-95. [PMID: 18313992 DOI: 10.1016/j.mito.2008.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 01/09/2008] [Accepted: 01/18/2008] [Indexed: 11/24/2022]
Abstract
Mitochondrial dysfunction has been implicated in the adverse effects of nucleoside reverse transcriptase inhibitors (NRTIs) used to treat HIV-1 infections. To gain insight into the mechanism by which NRTIs alter mitochondrial function, the expression level of 542 genes associated with mitochondrial structure and functions was determined in the livers of p53 haplodeficient (+/-) C3B6F1 female mouse pups using mouse mitochondria-specific oligonucleotide microarray. The pups were transplacentally exposed to zidovudine (AZT) at 240 mg/kg bw/day or a combination of AZT and lamivudine (3TC) at 160 and 100mg/kg bw/day, respectively, from gestation day 12 through 18, followed by continuous treatment by oral administration from postnatal day 1-28. In addition, AZT/3TC effect was investigated in wild-type (+/+) C3B6F1 female mice. The genotype did not significantly affect the gene expression profile induced by AZT/3TC treatment. However, the transcriptional level of several genes associated with oxidative phosphorylation, mitochondrial tRNAs, fatty acid oxidation, steroid biosynthesis, and a few transport proteins were significantly altered in pups treated with AZT and AZT/3TC compared to their vehicle counterparts. Interestingly, AZT/3TC altered the expression level of 153 genes with false discovery rate of less than 0.05, in contrast to only 20 genes by AZT alone. These results suggest that NRTI-related effect on expression level of genes associated with mitochondrial functions was much greater in response to AZT/3TC combination treatment than AZT alone.
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Walker DM, Malarkey DE, Seilkop SK, Ruecker FA, Funk KA, Wolfe MJ, Treanor CP, Foley JF, Hahn FF, Hardisty JF, Walker VE. Transplacental carcinogenicity of 3'-azido-3'-deoxythymidine in B6C3F1 mice and F344 rats. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:283-98. [PMID: 17358026 DOI: 10.1002/em.20297] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The prophylactic use of zidovudine (3'-azido-3'-deoxythymidine, AZT) during pregnancy greatly reduces transmission of HIV-1 from infected mothers to their infants; however, the affinity of host cell DNA polymerases for AZT also allows for its incorporation into host cell DNA, predisposing to cancer development. To expand upon previous transplacental carcinogenesis assays performed in CD-1 mice, the transplacental carcinogenicity of AZT was evaluated in a second mouse strain and a second rodent species. Date-mated female mice and rats were gavaged daily with 0, 80, 240, or 480 mg AZT/kg bw during the last 7 days of gestation. At 2 years postpartum, male and female B6C3F1 mouse and F344 rat offspring (n = 44-46 of each sex and species/treatment group) were necropsied for gross and microscopic tissue examinations. Under the conditions of these two-year studies, there was clear evidence of carcinogenic activity based upon significant dose-related trends and increases in the incidences of hemangiosarcoma in male mice and mononuclear cell leukemia in female rats. There was some evidence of carcinogenic activity in the livers of male mice based upon a positive trend and an increased incidence of hepatic carcinoma in the high-dose AZT group. The incidence of gliomas in female rats exceeded the historical background rates for gliomas in F344 rats. P53 overexpression was detected in some AZT-treated mouse neoplasms. These and other cancer-related findings confirm and extend those of previous transplacental carcinogenicity studies of AZT in mice, support the need for long-term follow-up of nucleoside reverse transcriptase inhibitor (NRTI)-exposed children, and indicate the necessity for effective protective strategies against NRTI-induced side effects.
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Affiliation(s)
- Dale M Walker
- Experimental Pathology Laboratories, Inc., Herndon, Virginia, USA
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