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Toxicity studies of (+)-usnic acid administered in feed to F344/N Nctr rats and B6C3F1/Nctr mice. TOXICITY REPORT SERIES 2022:NTP-TOX-104. [PMID: 36240030 PMCID: PMC9638889 DOI: 10.22427/ntp-tox-104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
(+)-Usnic acid is a secondary metabolite of lichens belonging to the Usnea genus. Usnea lichens and purified usnic acids have been used historically in traditional herbal medicine as bactericidal and antimicrobial agents. (+)-Usnic acid exhibits membrane proton uncoupling activity, which not only forms the mechanistic basis of its bactericidal action, but also has provided a rationale for its use as a fat-burning, weight-loss agent. Purified (+)-usnic acid has been marketed in the United States for this purpose either alone or in combination with other chemical agents. Use of some of these fat-burning products that contain (+)-usnic acid has resulted in serious liver damage. This study investigated the potential toxicity of (+)-usnic acid in male and female F344/N Nctr rats and B6C3F1/Nctr mice that were exposed via feed for 3 months. F344/N Nctr rats were administered 0, 30, 60, 120, 360, or 720 ppm in feed, while B6C3F1/Nctr mice were administered 0, 15, 30, 60, 180, or 360 ppm in feed. (Abstract Abridged).
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Liu K, Zang Y, Guo X, Wei F, Yin J, Pang L, Chen D. The Δ133p53 Isoform Reduces Wtp53-induced Stimulation of DNA Pol γ Activity in the Presence and Absence of D4T. Aging Dis 2017; 8:228-239. [PMID: 28400988 PMCID: PMC5362181 DOI: 10.14336/ad.2016.0910] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/10/2016] [Indexed: 01/02/2023] Open
Abstract
The mitochondrial toxicity of nucleoside reverse transcriptase inhibitors (NRTIs) is due to the inhibition of mitochondrial DNA (mtDNA) polymerase γ (pol γ). Previous studies have shown that wild type p53 (wtp53) can interact with pol γ and mtDNA to enhance mitochondrial DNA base excision repair (mtBER) activity and increase the accuracy of DNA synthesis. The N-terminal transactivation domain and central specific DNA-binding domain of p53 play critical roles in the stimulation of BER. In this study, we identified the possible roles of wtp53, Δ40p53 and Δ133p53 in regulating mtDNA pol γ activity in cells with d4T treatment. The results show that Δ40p53 and Δ133p53 can exist in mitochondrial fragments and form polymers with themselves or wtp53. Unlike wtP53, Δ133p53 alone cannot increase DNA pol γ activity. More importantly, we found that Δ133p53 played a negative role in p53 stimulation of DNA pol γ activity when studied in d4T-treated and d4T-untreated mitochondrial extracts. Gel shift data also indicate that Δ40p53 and Δ133p53 cannot interact with APE. Wtp53 and Δ40p53 can act antagonize the effect of d4T inhibition of DNA pol γ activity. However, when wtp53 interacted with Δ133p53, DNA pol γ activity was significantly decreased. Conclusion: Δ133p53 negatively regulates p53’s stimulation of pol γ in the presence and absence of d4T.
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Affiliation(s)
- Kai Liu
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
| | - Yunjin Zang
- 2The Affiliated Hospital of Qingdao University, Organ Transplantation Center, Qingdao, Shandong 266003, China
| | - Xianghua Guo
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
| | - Feili Wei
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
| | - Jiming Yin
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
| | - Lijun Pang
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
| | - Dexi Chen
- 1Beijing Institute of Hepatology, Beijing You An Hospital, Capital Medical University, Beijing 100069, China
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Momot D, Nostrand TA, John K, Ward Y, Steinberg SM, Liewehr DJ, Poirier MC, Olivero OA. Role of nucleotide excision repair and p53 in zidovudine (AZT)-induced centrosomal deregulation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:719-726. [PMID: 25073973 PMCID: PMC7675294 DOI: 10.1002/em.21889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 07/10/2014] [Indexed: 06/03/2023]
Abstract
The nucleoside reverse transcriptase inhibitor zidovudine (AZT) induces genotoxic damage that includes centrosomal amplification (CA > 2 centrosomes/cell) and micronucleus (MN) formation. Here we explored these end points in mice deficient in DNA repair and tumor suppressor function to evaluate their effect on AZT-induced DNA damage. We used mesenchymal-derived fibroblasts cultured from C57BL/6J mice that were null and wild type (WT) for Xpa, and WT, haploinsufficient and null for p53 (6 different genotypes). Dose-responses for CA formation, in cells exposed to 0, 10, and 100 μM AZT for 24 hr, were observed in all genotypes except the Xpa((+/+)) p53((+/-)) cells, which had very low levels of CA, and the Xpa((-/-)) p53((-/-)) cells, which had very high levels of CA. For CA there was a significant three-way interaction between Xpa, p53, and AZT concentration, and Xpa((-/-)) cells had significantly higher levels of CA than Xpa((+/+)) cells, only for p53((+/-)) cells. In contrast, the MN and MN + chromosomes (MN + C) data showed a lack of AZT dose response. The Xpa((-/-)) cells, with p53((+/+)) or ((+/-)) genotypes, had levels of MN and MN + C higher than the corresponding Xpa((+/+)) cells. The data show that CA is a major event induced by exposure to AZT in these cells, and that there is a complicated relationship between AZT and CA formation with respect to gene dosage of Xpa and p53. The loss of both genes resulted in high levels of damage, and p53 haploinsufficicency strongly protected Xpa((+/+)) cells from AZT-induced CA damage.
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Affiliation(s)
- Dariya Momot
- Carcinogen-DNA Interactions Section, LCBG, National Cancer Institute, NIH, Bethesda, Maryland
| | - Terri A. Nostrand
- Carcinogen-DNA Interactions Section, LCBG, National Cancer Institute, NIH, Bethesda, Maryland
| | - Kaarthik John
- Carcinogen-DNA Interactions Section, LCBG, National Cancer Institute, NIH, Bethesda, Maryland
| | - Yvona Ward
- Cell and Cancer Biology Branch, National Cancer Institute, NIH, Bethesda, Maryland
| | - Seth M. Steinberg
- Biostatistics and Data Management Section, National Cancer Institute, NIH, Bethesda, Maryland
| | - David J. Liewehr
- Biostatistics and Data Management Section, National Cancer Institute, NIH, Bethesda, Maryland
| | - Miriam C. Poirier
- Carcinogen-DNA Interactions Section, LCBG, National Cancer Institute, NIH, Bethesda, Maryland
| | - Ofelia A. Olivero
- Carcinogen-DNA Interactions Section, LCBG, National Cancer Institute, NIH, Bethesda, Maryland
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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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Eastmond DA, Vulimiri SV, French JE, Sonawane B. The use of genetically modified mice in cancer risk assessment: challenges and limitations. Crit Rev Toxicol 2014; 43:611-31. [PMID: 23985072 DOI: 10.3109/10408444.2013.822844] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The use of genetically modified (GM) mice to assess carcinogenicity is playing an increasingly important role in the safety evaluation of chemicals. While progress has been made in developing and evaluating mouse models such as the Trp53⁺/⁻, Tg.AC and the rasH2, the suitability of these models as replacements for the conventional rodent cancer bioassay and for assessing human health risks remains uncertain. The objective of this research was to evaluate the use of accelerated cancer bioassays with GM mice for assessing the potential health risks associated with exposure to carcinogenic agents. We compared the published results from the GM bioassays to those obtained in the National Toxicology Program's conventional chronic mouse bioassay for their potential use in risk assessment. Our analysis indicates that the GM models are less efficient in detecting carcinogenic agents but more consistent in identifying non-carcinogenic agents. We identified several issues of concern related to the design of the accelerated bioassays (e.g., sample size, study duration, genetic stability and reproducibility) as well as pathway-dependency of effects, and different carcinogenic mechanisms operable in GM and non-GM mice. The use of the GM models for dose-response assessment is particularly problematic as these models are, at times, much more or less sensitive than the conventional rodent cancer bioassays. Thus, the existing GM mouse models may be useful for hazard identification, but will be of limited use for dose-response assessment. Hence, caution should be exercised when using GM mouse models to assess the carcinogenic risks of chemicals.
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Affiliation(s)
- David A Eastmond
- Department of Cell Biology & Neuroscience, University of California, Riverside, CA 92521, USA.
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Olivero OA, Torres LR, Gorjifard S, Momot D, Marrogi E, Divi RL, Liu Y, Woodward RA, Sowers MJ, Poirier MC. Perinatal exposure of patas monkeys to antiretroviral nucleoside reverse-transcriptase inhibitors induces genotoxicity persistent for up to 3 years of age. J Infect Dis 2013; 208:244-8. [PMID: 23559463 DOI: 10.1093/infdis/jit146] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Erythrocebus patas (patas) monkeys were used to model antiretroviral (ARV) drug in human immunodeficiency virus type 1-infected pregnant women. METHODS Pregnant patas dams were given human-equivalent doses of ARVs daily during 50% of gestation. Mesenchymal cells, cultured from bone marrow of patas offspring obtained at birth and at 1 and 3 years of age, were examined for genotoxicity, including centrosomal amplification, micronuclei, and micronuclei containing whole chromosomes. RESULTS Compared with controls, statistically significant increases (P < .05) in centrosomal amplification, micronuclei, and micronuclei containing whole chromosomes were found in mesenchymal cells from most groups of offspring at the 3 time points. CONCLUSIONS Transplacental nucleoside reverse-transcriptase inhibitor exposures induced fetal genotoxicity that was persistent for 3 years.
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Affiliation(s)
- Ofelia A Olivero
- Carcinogen-DNA Interactions Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD 20892-4255, USA
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Campos PB, Sartore RC, Ramalho BL, Costa ES, Rehen SK. Cycle arrest and aneuploidy induced by zidovudine in murine embryonic stem cells. Mutagenesis 2012; 27:431-6. [DOI: 10.1093/mutage/ger093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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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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Dertinger SD, Torous DK, Hayashi M, MacGregor JT. Flow cytometric scoring of micronucleated erythrocytes: an efficient platform for assessing in vivo cytogenetic damage. Mutagenesis 2010; 26:139-45. [DOI: 10.1093/mutage/geq055] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Incidence of cancer in children perinatally exposed to nucleoside reverse transcriptase inhibitors. AIDS 2008; 22:2165-77. [PMID: 18832880 DOI: 10.1097/qad.0b013e328311d18b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
CONTEXT Long-term studies of tolerance to perinatal exposure to antiretroviral nucleoside reverse transcriptase inhibitors are required, in view of the potential genotoxicity of some of these molecules. OBJECTIVE To evaluate the incidence of cancers in uninfected children born to HIV-infected mothers. METHOD Cancers were detected in a nationwide prospective cohort of children born to HIV-infected mothers by standardized questionnaire during the prospective follow-up period of 2 years; thereafter, they were detected by spontaneous pharmacovigilance declaration and by crosschecking data with the national registries of childhood cancer. Standardized incidence ratio for incidence comparisons with general population. RESULTS Ten cases of cancer were detected among the 9127 exposed HIV-uninfected children (median age: 5.4 years, 53 052 person-years of follow-up). The overall incidence did not differ significantly from that expected for the general population: 10 cases observed versus 8.9 and 9.6 expected depending on whether 1990-1999 or 2000-2004 national rates were used as reference [standardized incidence ratio of 1.1 (0.3-1.5) and 1.0 (0.5-1.9)]. Five cases of central nervous system cancer were observed (standardized incidence ratio of 3.1 [1.0-7.2] P = 0.05 and 2.4 [0.8-5.6], P = 0.12). The relative risk of cancer for children exposed to didanosine-lamivudine combination was higher than that for zidovudine monotherapy [hazard ratio: 13.6 (2.5-73.9)]. CONCLUSION This study did not evidence an overall increase in cancer risk in nucleoside reverse transcriptase inhibitor exposed children until 5 years of age. Results suggesting associations with specific nucleoside reverse transcriptase inhibitor combinations need further investigations. A longer surveillance, including differential analysis of the different cancer sites and various nucleoside reverse transcriptase inhibitors administered is warranted.
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