scholarly journals Cytotoxicity and Mutagenicity of Narrowband UVB to Mammalian Cells

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 646
Author(s):  
Dylan J. Buglewicz ◽  
Jacob T. Mussallem ◽  
Alexis H. Haskins ◽  
Cathy Su ◽  
Junko Maeda ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Skin Diseases ◽  
Excision Repair ◽  
Chinese Hamster ◽  
Ultraviolet B ◽  
Pyrimidine Dimer ◽  
Ros Generation ◽  
Narrowband Uvb ◽  
The Difference ◽  
Uvb Exposure

Phototherapy using narrowband ultraviolet-B (NB-UVB) has been shown to be more effective than conventional broadband UVB (BB-UVB) in treating a variety of skin diseases. To assess the difference in carcinogenic potential between NB-UVB and BB-UVB, we investigated the cytotoxicity via colony formation assay, genotoxicity via sister chromatid exchange (SCE) assay, mutagenicity via hypoxanthine phosphoribosyltransferase (HPRT) mutation assay, as well as cyclobutane pyrimidine dimer (CPD) formation and reactive oxygen species (ROS) generation in Chinese hamster ovary (CHO) and their NER mutant cells. The radiation dose required to reduce survival to 10% (D10 value) demonstrated BB-UVB was 10 times more cytotoxic than NB-UVB, and revealed that NB-UVB also induces DNA damage repaired by nucleotide excision repair. We also found that BB-UVB more efficiently induced SCEs and HPRT mutations per absorbed energy dosage (J/m2) than NB-UVB. However, SCE and HPRT mutation frequencies were observed to rise in noncytotoxic dosages of NB-UVB exposure. BB-UVB and NB-UVB both produced a significant increase in CPD formation and ROS formation (p < 0.05); however, higher dosages were required for NB-UVB. These results suggest that NB-UVB is less cytotoxic and genotoxic than BB-UVB, but can still produce genotoxic effects even at noncytotoxic doses.

scholarly journals Repair of abasic sites by mammalian cell extracts

1994 ◽  
Vol 304 (3) ◽  
pp. 699-705 ◽  
Author(s):  
G Frosina ◽  
P Fortini ◽  
O Rossi ◽  
F Carrozzino ◽  
A Abbondandolo ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Excision Repair ◽  
Chinese Hamster ◽  
Pyrimidine Dimer ◽  
Repair Synthesis ◽  
Repair Patch ◽  
Cell Extracts ◽  
Pyrimidine Dimers ◽  
Ap Sites ◽  
Ap Site

Hamster cell extracts that perform repair synthesis on covalently closed circular DNA containing pyrimidine dimers, were used to study the repair of apurinic/apyrimidinic (AP) sites and methoxyamine (MX)-modified AP sites. Plasmid molecules were heat-treated at pH 5 and incubated with MX when required. The amount of damage introduced ranged from 0.2 to 0.9 AP sites/kb. Extracts were prepared from the Chinese hamster ovary CHO-9 cell line and from its derivative, 43-3B clone which is mutated in the nucleotide excision repair (NER) ERCC1 gene. AP and MX-AP sites stimulated repair synthesis by CHO-9 cell extracts. The level of synthesis correlated with the number of lesions and was of similar magnitude to the repair stimulated by 4.3 u.v. photoproducts/kb. Repair of AP and MX-AP sites was faster than the repair of u.v. damage and was independent of ERCC1 gene product. The high level of repair replication was due to a very efficient and rapid incision of plasmids carrying AP or MX-AP sites, performed by abundant AP endonucleases present in the extract. The calculated average repair patch sizes were: 7 nucleotides per AP site; 10 nucleotides per MX-AP site; 28 nucleotides per (6-4) u.v. photoproduct or cyclobutane pyrimidine dimer. The data indicate that AP and MX-AP sites are very efficiently repaired by base-excision repair in mammalian cells and suggest that MX-AP sites may also be processed via alternative repair mechanisms.

scholarly journals An interaction between the mammalian DNA repair protein XRCC1 and DNA ligase III.

1994 ◽  
Vol 14 (1) ◽  
pp. 68-76 ◽  
Author(s):  
K W Caldecott ◽  
C K McKeown ◽  
J D Tucker ◽  
S Ljungquist ◽  
L H Thompson
Keyword(s):  
Dna Repair ◽  
Affinity Chromatography ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Affinity Purification ◽  
Alkylating Agents ◽  
Chinese Hamster ◽  
Dna Ligase ◽  
Base Excision ◽  
Dna Ligase Iii

XRCC1, the human gene that fully corrects the Chinese hamster ovary DNA repair mutant EM9, encodes a protein involved in the rejoining of DNA single-strand breaks that arise following treatment with alkylating agents or ionizing radiation. In this study, a cDNA minigene encoding oligohistidine-tagged XRCC1 was constructed to facilitate affinity purification of the recombinant protein. This construct, designated pcD2EHX, fully corrected the EM9 phenotype of high sister chromatid exchange, indicating that the histidine tag was not detrimental to XRCC1 activity. Affinity chromatography of extract from EM9 cells transfected with pcD2EHX resulted in the copurification of histidine-tagged XRCC1 and DNA ligase III activity. Neither XRCC1 or DNA ligase III activity was purified during affinity chromatography of extract from EM9 cells transfected with pcD2EX, a cDNA minigene that encodes untagged XRCC1, or extract from wild-type AA8 or untransfected EM9 cells. The copurification of DNA ligase III activity with histidine-tagged XRCC1 suggests that the two proteins are present in the cell as a complex. Furthermore, DNA ligase III activity was present at lower levels in EM9 cells than in AA8 cells and was returned to normal levels in EM9 cells transfected with pcD2EHX or pcD2EX. These findings indicate that XRCC1 is required for normal levels of DNA ligase III activity, and they implicate a major role for this DNA ligase in DNA base excision repair in mammalian cells.

scholarly journals A Role for DNA Polymerase β in Mutagenic UV Lesion Bypass

2002 ◽  
Vol 277 (51) ◽  
pp. 50046-50053 ◽  
Author(s):  
Laurence Servant ◽  
Christophe Cazaux ◽  
Anne Bieth ◽  
Shigenori Iwai ◽  
Fumio Hanaoka ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Genetic Instability ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Pyrimidine Dimer ◽  
Dna Polymerase Β ◽  
Lesion Bypass ◽  
Base Excision

We report here that DNA polymerase β (pol β), the base excision repair polymerase, is highly expressed in human melanoma tissues, known to be associated with UV radiation exposure. To investigate the potential role of pol β in UV-induced genetic instability, we analyzed the cellular and molecular effects of excess pol β. We firstly demonstrated that mammalian cells overexpressing pol β are resistant and hypermutagenic after UV irradiation and that replicative extracts from these cells are able to catalyze complete translesion replication of a thymine-thymine cyclobutane pyrimidine dimer (CPD). By usingin vitroprimer extension reactions with purified pol β, we showed that CPD as well as, to a lesser extent, the thymine-thymine pyrimidine-pyrimidone (6-4) photoproduct, were bypassed. pol β mostly incorporates the correct dATP opposite the 3′-terminus of both CPD and the (6-4) photoproduct but can also misinsert dCTP at a frequency of 32 and 26%, respectively. In the case of CPD, efficient and error-prone extension of the correct dATP was found. These data support a biological role of pol β in UV lesion bypass and suggest that deregulated pol β may enhance UV-induced genetic instability.

scholarly journals Echinacoside Alleviates UVB Irradiation-Mediated Skin Damage via Inhibition of Oxidative Stress, DNA Damage, and Apoptosis

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Di Zhang ◽  
Chengtao Lu ◽  
Zhe Yu ◽  
Xiayin Wang ◽  
Li Yan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Histopathological Examination ◽  
Ultraviolet B ◽  
Ros Generation ◽  
Antioxidant Enzyme Activities ◽  
Skin Damage ◽  
Uvb Irradiation ◽  
Uvb Exposure

Ultraviolet B (UVB) irradiation has been known to cause skin damage, which is associated with oxidative stress, DNA damage, and apoptosis. Echinacoside is a phenylethanoid glycoside isolated from Herba Cistanches, which exhibits strong antioxidant activity. In this study, we evaluate the photoprotective effect of echinacoside on UVB-induced skin damage and explore the potential molecular mechanism. BALB/c mice and HaCaT cells were treated with echinacoside before UVB exposure. Histopathological examination was used to evaluate the skin damage. Cell viability, lactate dehydrogenase (LDH) levels, antioxidant enzyme activities, reactive oxygen species (ROS) generation, DNA damage, and apoptosis were measured as well. Western blot was used to measure the expression of related proteins. The results revealed that pretreatment of echinacoside ameliorated the skin injury; attenuated oxidative stress, DNA damage, and apoptosis caused by UVB exposure; and normalized the protein levels of ATR, p53, PIAS3, hnRNP K, PARP, and XPA. To summarize, echinacoside is beneficial in the prevention of UVB-induced DNA damage and apoptosis of the skin in vivo and in vitro.

scholarly journals Tryptophan Photoproduct FICZ Upregulates IL1A, IL1B, and IL6 Expression via Oxidative Stress in Keratinocytes

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yuka Tanaka ◽  
Hiroshi Uchi ◽  
Akiko Hashimoto-Hachiya ◽  
Masutaka Furue
Keyword(s):  
Proinflammatory Cytokine ◽  
Protein Product ◽  
Ultraviolet B ◽  
Ros Generation ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Hacat Keratinocytes ◽  
Uvb Irradiation ◽  
Aryl Hydrocarbon ◽  
Uvb Exposure

Ultraviolet B (UVB) irradiation activates the aryl hydrocarbon receptor (AHR), generates the reactive oxygen species (ROS), and induces the production of proinflammatory cytokines such as IL1A, IL1B, and IL6. 6-Formylindolo[3,2-b]carbazole (FICZ) is a tryptophan-derived photoproduct that is induced by UVB irradiation and activates the AHR. However, its role in upregulating proinflammatory cytokine expression has never been investigated. Here, we demonstrated that FICZ enhanced ROS generation in human HaCaT keratinocytes in an AHR-dependent manner. FICZ also upregulated the expression of IL1A and IL1B, as well as the expression of IL6 and the production of its protein product, in an AHR- and ROS-dependent fashion. Here, we demonstrate that the actions of FICZ can substitute for the hazardous effects of UVB exposure, contributing to the further understandings of the mechanisms which UVB harms organisms.

An interaction between the mammalian DNA repair protein XRCC1 and DNA ligase III

1994 ◽  
Vol 14 (1) ◽  
pp. 68-76
Author(s):  
K W Caldecott ◽  
C K McKeown ◽  
J D Tucker ◽  
S Ljungquist ◽  
L H Thompson
Keyword(s):  
Dna Repair ◽  
Affinity Chromatography ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Affinity Purification ◽  
Alkylating Agents ◽  
Chinese Hamster ◽  
Dna Ligase ◽  
Base Excision ◽  
Dna Ligase Iii

XRCC1, the human gene that fully corrects the Chinese hamster ovary DNA repair mutant EM9, encodes a protein involved in the rejoining of DNA single-strand breaks that arise following treatment with alkylating agents or ionizing radiation. In this study, a cDNA minigene encoding oligohistidine-tagged XRCC1 was constructed to facilitate affinity purification of the recombinant protein. This construct, designated pcD2EHX, fully corrected the EM9 phenotype of high sister chromatid exchange, indicating that the histidine tag was not detrimental to XRCC1 activity. Affinity chromatography of extract from EM9 cells transfected with pcD2EHX resulted in the copurification of histidine-tagged XRCC1 and DNA ligase III activity. Neither XRCC1 or DNA ligase III activity was purified during affinity chromatography of extract from EM9 cells transfected with pcD2EX, a cDNA minigene that encodes untagged XRCC1, or extract from wild-type AA8 or untransfected EM9 cells. The copurification of DNA ligase III activity with histidine-tagged XRCC1 suggests that the two proteins are present in the cell as a complex. Furthermore, DNA ligase III activity was present at lower levels in EM9 cells than in AA8 cells and was returned to normal levels in EM9 cells transfected with pcD2EHX or pcD2EX. These findings indicate that XRCC1 is required for normal levels of DNA ligase III activity, and they implicate a major role for this DNA ligase in DNA base excision repair in mammalian cells.

Preferential repair of damage in actively transcribed DNA sequences in vivo

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 605-611 ◽  
Author(s):  
Philip C. Hanawalt
Keyword(s):  
Dna Repair ◽  
Dna Sequences ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Chinese Hamster ◽  
Human Cells ◽  
Dhfr Gene ◽  
Pyrimidine Dimers ◽  
Cross Links

My colleagues and I have discovered intragenomic heterogeneity in DNA repair in mammalian cells. Consequences of unrepaired DNA damage depend upon the precise location of the damage with respect to relevant genes. It is therefore important to understand rules governing accessibility of specific DNA sequences in chromatin to damage and repair. The efficiency of removal of pyrimidine dimers has been determined in the active dihydrofolate reductase (DHFR) gene in Chinese hamster ovary (CHO) cells. Repair within the gene was shown to be much more efficient than that in nontranscribed downstream sequences or in the genome overall. Preferential repair of active and essential genes such as DHFR may account for the fact that rodent cells are as uv-resistant as human cells in spite of their much lower overall repair efficiencies. In repair-proficient human cells the rate of repair in the DHFR gene is greater than that in the overall genome or in nontranscribed α-DNA sequences. The efficiency of removal of pyrimidine dimers is much higher in the transcribed than the nontranscribed DNA strands of the DHFR gene in both CHO and human cells. An excision–repair complex may be directly coupled to the transcription machinery to ensure early removal of transcription-blocking lesions in active genes. Sequences in the active c-abl proto-oncogene are repaired much more efficiently than are sequences containing the inactive c-mos proto-oncogene in Swiss mouse 3T3 cells. Tissue-specific and cell-specific differences in the coordinate regulation of proto-oncogene expression and DNA repair may account for corresponding differences in the carcinogenic response. Efficient replicative bypass of persisting psoralen monoadducts, but not interstrand cross-links, was demonstrated in the human DHFR gene. It is likely that most bulky lesions in mammalian DNA, other than cross-links, do not pose insurmountable problems for replication in vivo, but they must be removed from essential transcribed sequences to maintain cellular viability.Key words: DNA repair, chromatin, transcription, mammalian cells, pyrimidine dimers, ultraviolet light, DNA cross-links.

scholarly journals Ectopic Expression of DNA Repair Enzymes Modulates Survival following Ultraviolet Irradiation Challenge

2017 ◽  
Author(s):  
Stuti P. Garg ◽  
Irina G. Minko ◽  
Erdem Coskun ◽  
Onur Erdem ◽  
Pawel Jaruga ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Excision Repair ◽  
Uv Light ◽  
Ectopic Expression ◽  
Pyrimidine Dimer ◽  
Biologically Relevant ◽  
E Coli ◽  
Pyrimidine Dimers ◽  
Uvb Exposure ◽  
Base Excision

AbstractIn Escherichia coli, the nucleotide excision repair (NER) pathway removes ultraviolet (UV) light-induced cyclobutane pyrimidine dimers (CPDs) and 6-4 dipyrimidine photoproducts (6-4 PPs). Activation of alternative repair pathways, such as base excision repair (BER) and nucleotide incision repair (NIR), is inoperative because this organism lacks both the necessary BER DNA glycosylase and NIR UV endonuclease to initiate repair of these lesions. To determine if initiation of either pathway would enhance survival to biologically-relevant UV irradiation, the BER and NIR pathways were activated by expression of Chlorella virus-1 pyrimidine dimer glycosylase (cv-pdg) and Schizosaccharomyces pombe UV endonuclease (UVDE), respectively. The substrate specificity of cv-pdg includes CPDs and ring-fragmented purines, 4,6-diamino-5-formamidopyrimidine and 2,6-diamino-4-hydroxy-5-formamidopyrimidine, but not 6-4 PPs. In contrast, while UVDE incises DNA containing CPDs and 6-4 PPs, it was not previously known if the substrate specificity of UVDE included DNA containing ring-fragmented purines. Mass spectrometry was used to establish that these oxidatively-induced lesions were not substrates for UVDE. Expression of either cv-pdg or UVDE in NER-deficient E. coli significantly enhanced survival following UVB irradiation, but not to the levels of wild type (WT) cells. Survival of NER-proficient, homologous recombination-deficient cells could also be significantly enhanced by expression of either enzyme, suggesting that in response to UVB exposure, interactions between NER and activated BER or NIR pathways could be additive. Further, expression of cv-pdg or UVDE in WT E. coli enhanced survival following solar-simulated light (SSL) exposures.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

Efficacy and Safety of Oral Ivermectin and Topical Permethrin in the Treatment of Scabies

2020 ◽  
Vol 33 (1) ◽  
pp. 41-47
Author(s):  
Mohsena Akhter ◽  
Ishrat Bhuiyan ◽  
Zulfiqer Hossain Khan ◽  
Mahfuza Akhter ◽  
Gulam Kazem Ali Ahmad ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Close Contact ◽  
Randomized Study ◽  
Sarcoptes Scabiei ◽  
Efficacy And Safety ◽  
Common Skin ◽  
Group A ◽  
The Mean ◽  
The Difference ◽  
Group B

Background: Scabies is one of the most common skin diseases in our country. It is caused by the mite Sarcoptes scabiei var hominis, which is an ecto-parasite infesting the epidermis. Scabies is highly contagious. Prevalence is high in congested or densely populated areas. Individuals with close contact with an affected person should be treated with scabicidal which is available in both oral and topical formulations. The only oral but highly effective scabicidal known to date is Ivermectin. Amongst topical preparations, Permethrin 5 % cream is the treatment of choice. Objective: To evaluate the efficacy & safety of oral Ivermectin compared to topical Permethrin in the treatment of scabies. Methodology: This prospective, non-randomized study was conducted at the out-patient department of Dermatology and Venereology of Shaheed Suhrawardy Medical College & Hospital over a period of 6 months, from August 2016 to January 2017. The study population consisted of one hundred patients having scabies, enrolled according to inclusion criteria. They were divided into two groups. group A was subjected to oral Ivermectin and the group B to Permethrin 5% cream. Patients were followed up on day 7 and 14 for assessment of efficacy and safety. Result: The mean scoring with SD in group A (Ivermectin) and group B (Permethrin) were 8.26 ± 2.22 and 7.59 ± 2.01 respectively at the time of observation. The difference between the mean score of the two group is not significant (p=0.117) the mean scoring with SD in group A and group B were 4.54 ± 2.05 and 1.64 ± 1.84 respectively at 7thdays. The difference between the mean score of the two group is significant (p<0.001). The mean scoring with SD in group A and group B were 2.68± 2.35 and .36± 1.10 respectively at 14th day difference between the mean score of the group is significant (p<0.001). Conclusion: Topical application of permethrin 5% cream is more effective and safer than oral Ivermectin in the treatment of scabies. TAJ 2020; 33(1): 41-47

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