ABSTRACT
Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T. cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.
O reparo por excisão de nucleotídeos (NER) atua reparando danos no DNA, como lesões causadas por cisplatina. A proteína Xeroderma Pigmentosum complementation group C (XPC) está envolvida no reconhecimento de danos pela via de reparação global do genoma pelo NER (GG-NER) e tem sido estudada em diferentes organismos devido à sua importância em outros processos celulares. Neste trabalho, estudamos proteínas do NER em Trypanosoma cruzi e Trypanosoma evansi, parasitos de humanos e animais, respectivamente. Modelos tridimensionais das proteínas XPC de T. cruzi e T. evansi foram feitos e observou-se poucas diferenças estruturais entre estas proteínas. Durante testes, a inserção do gene XPC de T. evansi (TevXPC) em T. cruzi resultou em crescimento celular mais lento em condições normais. Após o tratamento com cisplatina, T. cruzi superexpressando seu próprio gene XPC (TcXPC) foi capaz de recuperar as taxas de divisão celular mais rapidamente do que T. cruzi expressando o gene TevXPC. Com base nesses testes, sugere-se que TevXPC (sendo uma proteína exógena em T. cruzi) interfere negativamente nos processos celulares em que TcXPC (a proteína endógena) está envolvida. Isso provavelmente ocorreu pois TevXPC é capaz de interagir com algumas moléculas ou proteínas endógenas de T. cruzi, mas é incapaz de interagir com outras. Isso reforça a importância do correto funcionamento de XPC dentro da célula.
Subject(s)
Animals , Crosses, Genetic , DNA Damage , Gene Expression , Trypanosoma cruzi/geneticsABSTRACT
Abstract Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T.cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.
Resumo O reparo por excisão de nucleotídeos (NER) atua reparando danos no DNA, como lesões causadas por cisplatina. A proteína Xeroderma Pigmentosum complementation group C (XPC) está envolvida no reconhecimento de danos pela via de reparação global do genoma pelo NER (GG-NER) e tem sido estudada em diferentes organismos devido à sua importância em outros processos celulares. Neste trabalho, estudamos proteínas do NER em Trypanosoma cruzi e Trypanosoma evansi, parasitos de humanos e animais, respectivamente. Modelos tridimensionais das proteínas XPC de T. cruzi e T. evansi foram feitos e observou-se poucas diferenças estruturais entre estas proteínas. Durante testes, a inserção do gene XPC de T. evansi (TevXPC) em T. cruzi resultou em crescimento celular mais lento em condições normais. Após o tratamento com cisplatina, T. cruzi superexpressando seu próprio gene XPC (TcXPC) foi capaz de recuperar as taxas de divisão celular mais rapidamente do que T. cruzi expressando o gene TevXPC. Com base nesses testes, sugere-se que TevXPC (sendo uma proteína exógena em T. cruzi) interfere negativamente nos processos celulares em que TcXPC (a proteína endógena) está envolvida. Isso provavelmente ocorreu pois TevXPC é capaz de interagir com algumas moléculas ou proteínas endógenas de T.cruzi, mas é incapaz de interagir com outras. Isso reforça a importância do correto funcionamento de XPC dentro da célula.
ABSTRACT
Abstract Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T.cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.
Resumo O reparo por excisão de nucleotídeos (NER) atua reparando danos no DNA, como lesões causadas por cisplatina. A proteína Xeroderma Pigmentosum complementation group C (XPC) está envolvida no reconhecimento de danos pela via de reparação global do genoma pelo NER (GG-NER) e tem sido estudada em diferentes organismos devido à sua importância em outros processos celulares. Neste trabalho, estudamos proteínas do NER em Trypanosoma cruzi e Trypanosoma evansi, parasitos de humanos e animais, respectivamente. Modelos tridimensionais das proteínas XPC de T. cruzi e T. evansi foram feitos e observou-se poucas diferenças estruturais entre estas proteínas. Durante testes, a inserção do gene XPC de T. evansi (TevXPC) em T. cruzi resultou em crescimento celular mais lento em condições normais. Após o tratamento com cisplatina, T. cruzi superexpressando seu próprio gene XPC (TcXPC) foi capaz de recuperar as taxas de divisão celular mais rapidamente do que T. cruzi expressando o gene TevXPC. Com base nesses testes, sugere-se que TevXPC (sendo uma proteína exógena em T. cruzi) interfere negativamente nos processos celulares em que TcXPC (a proteína endógena) está envolvida. Isso provavelmente ocorreu pois TevXPC é capaz de interagir com algumas moléculas ou proteínas endógenas de T.cruzi, mas é incapaz de interagir com outras. Isso reforça a importância do correto funcionamento de XPC dentro da célula.
Subject(s)
Humans , Animals , Trypanosoma cruzi/genetics , Xeroderma Pigmentosum , DNA Damage/genetics , Computational Biology , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , DNA Repair/geneticsABSTRACT
Objective:To summarize the clinical manifestations and gene mutation features of patients with nucleotide excision repair (NER) disorders.Methods:A retrospective analysis was made on clinical data of patients with NER disorders who were admitted to the Chinese People′s Liberation Army General Hospital from October 2008 to February 2022 and diagnosed in the Outpatient Department of Beijing Children′s Hospital, Capital Medical University from October 2015 to February 2022.Literature on previously reported Chinese patients with NER disorders was reviewed.Results:(1)A total of 16 patients with NER disorders were enrolled, including 6 males and 10 females.The onset age was 7.5 (4.0, 12.0) months and the age at diagnosis was 42.0 (21.5, 77.0) months.There were 3 types of NER disorders: Cockayne syndrome (CS) in 13 cases, Xeroderma Pigmentosum (XP) in 2 cases and Cerebro-Oculo-Facio-Skeletal syndrome (COFS) in 1 case.Four disease-causing genes were detected: CSA gene in 11 cases, CSB gene in 3 cases, XPG gene in 1 case, and XPD gene in 1 case.The first symptoms of the 16 patients were photosensitivity and developmental delay, and neurological symptoms were observed in all the 3 NER disorder types.XP and CS patients had skin symptoms.CS patients presented typical facial features, visual and auditory impairment, microcephaly and changes in neuroimaging features.COFS patients showed intrauterine growth retardation.(2)Results of literature review: a total of 96 Chinese patients reported were retrieved, involving 6 disease types, including CS in 45 cases, XP in 44 cases, trichothiodystrophy in 4 cases, COFS in 1 case, XP-CS in 1 case, and ultraviolet sensitive syndrome in 1 case.Nine mutated genes were identified: CSA in 33 cases, XPA in 15 cases, CSB in 13 cases, XPV in 10 cases, XPC in 9 cases, XPG in 7 cases, XPD in 7 cases, XPF in 1 case, and MPLKIP in 1 case.The common symptoms were growth failure (62 cases), skin photosensitivity (61 cases), typical facial features (52 cases), mental retardation (49 cases) and microcephaly (48 cases). Among 36 cases had imaging data 33 cases(91.7%)had calcification of basal nucleus or globus pallidus.Three cases had intrauterine growth retardation and microcephaly during pregnancy. Conclusions:Patients with such prenatal manifestations as intrauterine growth retardation and microcephaly or with typical symptoms like skin photosensitivity, typical facial features, growth failure, mental retardation, hypertonia, and calcifications of basal ganglia should be suspected of NER disorders.Early genetic testing is recommended to confirm the diagnosis.
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Aim: To examine the possible role of nucleotide excision repair (NER) in affecting the ultimate mutagenic potency of 2,6- and 3,5-dimethylaniline (DMA) and their metabolites.Methodology: Two cell lines, nucleotide excision repair (NER)-proficient AA8 and deficient UV5 cells were treated with 50, 100, 250, 500 and 1000 μM of 2,6- and 3,5-DMA for 48 hr or their N-hydroxyl and aminophenol metabolites for 1 hr. Cell survival was determined by trypan blue exclusion assay, and 8-azaadenine-resistant mutants at adenine phosphoribosyltransferase (aprt) gene locus were evaluated.Results: A dose-dependent increase in cytotoxicity and mutant fraction was observed in AA8 and UV5 cells, treated with 2,6- and 3,5-DMA and their metabolites, but showed considerable variation in potency; N-hydroxyl and aminophenol metabolites of 2,6- and 3,5-DMA in serum-free α-minimal essential medium (MEM) having the highest potency, and 2,6- and 3,5-DMA in regular MEM at least. Repair-deficient UV5 cells were more sensitive to cytotoxic and mutagenic action than repair-proficient AA8 cells. Interpretation: These findings suggest that 2,6- and 3,5-DMA-induced DNA damage response may trigger cytotoxicity and mutagenicity when not completely repaired
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Objective To make a parallel mining the data of expression differences of a crucial gene XPA involved in nucleotide excision repair pathway of human skin microarrays by bioinformatics from the system level.Methods Using the ScanGEO, the data of microarrays which included the significant differences expression level of XPA were screened and analyzed from 59 human skin samples in the GEO database. Results There were 7 samples with the down-regulated expression of XPA: cutaneous malignant melanoma, epidermal injury model, DNA damage and UV radiation, foreskin fibroblast response to Toxoplasma gondii RH type 1 (ROP5) mutant infection, interleukin-20 subfamily cytokines effect on epidermal keratinocytes, Egr-1 overexpression effect on skin fibroblasts in vitro: time course, in vitro model for inflammatory dendritic cells.Present expression down. Conclusion Based on the GEO database and ScanGEO, high-throughput shared data can be screened and analyzed efficiently.
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Objective To examine the protein expression of the nucleotide excision repair gene (ERCC-1) in patients with locally advanced cervical cancer and its relationship with the efficacy of radiotherapy and chemotherapy.Methods The expression of ERCC-1 protein in 88 patients with locally advanced cervical cancer treated in our hospital between 2007-2011 was measured using immunohistochemistry (IHC).The patients were divided into high-expression group (n=48) and low-expression group (n=40) based on the fluorescence intensity on the IHC staining.All patients received cisplatin (40 mg/m2 per week) during radiotherapy.The relationship between ERCC-1 protein expression and the clinicopathological factors of cervical cancer was analyzed using the chi-square test.Survival was calculated using the Kaplan-Meier method and compared by the log-rank test.Multivariate prognostic analysis was performed using the Cox model.Results The overall response rate (CR+PR) was 81%(39/48) in the high-ERCC-1 expression group and 85%(34/40) in the low-ERCC-1 expression group (P=0.641).ERCC-1 protein expression was associated with recurrence and metastasis (P=0.043,0.043).The 5-year survival rate was significantly higher in the low-ERCC-1 expression group than in the high-ERCC-1 expression group (65% vs.42%, P=0.029).Conclusions Patients with high ERCC-1 protein expression are more likely to have local recurrence and distant metastasis than those with low ERCC-1 protein expression.ERCC-1 protein expression may be a clinically significant biomarker for predicting the prognosis of cervical cancer patients.
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Objective To explore the function of ERCC2/XPD polymorphisms in the repair of DNA damage induced by UVC. Methods Plas?mids stably expressing ERCC2/XPD rs13181 AA(Lys751)and ERCC2/XPD rs13181 CC(Gln751)were transfected into Chinese hamster ovary cells,and the stable ERCC2 transfected cell lines were obtained. MTT assay was used to compare the inhibitory rates of the transfected cells treated with UVC at different irradiation intensity. The DNA damage repair ability of the transfected cells treated with UVC for 1,3,6 and 24 h was detected by modified comet assay. Results Compared with UV5ERCC2(CC),UV5ERCC2(CC) was more sensitive to UVC with decreased cell viability. DNA damage level of UV5ERCC2(CC) cells was more serious than UV5ERCC2(CC). Conclusion DNA repair capacity of ERCC2/XPD rs13181A allelic is lower than its wild?type,suggesting that ERCC2/XPDpolymorphisms play a critical role in UVC?induced DNA damage repair.
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INTRODUCCIÓN: deficiencias en los mecanismos de reparación del ácido desoxirribonucleico constituyen un factor de riesgo para el desarrollo del cáncer, como ocurre en el xeroderma pigmentoso. OBJETIVOS: evaluar el fenotipo de la reparación por escisión de nucleótidos en pacientes cubanos con una elevada hipersensibilidad al sol, y la sospecha clínica de xeroderma pigmentoso en la fase eritematopigmentaria, mediante la variante alcalina del ensayo cometa. MÉTODOS: se estudiaron 28 pacientes, con predominio de las edades pediátricas. Como inductor del daño al ácido desoxirribonucleico se utilizó la radiación ultravioleta C (254 nm) a una dosis de 40 J/m². El daño del ácido desoxirribonucleico se cuantificó inmediatamente, después de irradiar las células (tiempo 0 minutos) y un tiempo después de la irradiación, incubado a 37 ºC en medio de cultivo, enriquecido con suero fetal al 10 % (tiempo 45 min). Con estos datos se determinó el por ciento de la diferencia en las unidades arbitrarias (UA) entre ambos momentos. RESULTADOS: no se obtuvieron diferencias significativas (p= 0,080976) entre el grupo de pacientes (224,23 UA) y el grupo de sujetos controles (195,43 UA). Los pacientes reconocieron y escindieron el daño inducido en el ácido desoxirribonucleico por luz ultravioleta C, con una eficiencia similar a la de los controles. CONCLUSIONES: el ensayo cometa alcalino acoplado a radiación ultravioleta C permitió identificar, claramente y de forma indirecta, el funcionamiento de los mecanismos de reparación por escisión de nucleótidos, donde actúan las proteínas XPA a XPG. Los sujetos en estudio fueron excluidos de presentar la forma clásica de la enfermedad.
INTRODUCTION: deficiencies in the deoxyribonucleic acid repair mechanisms are a risk factor for cancer as is the case of xeroderma pigmentosum. OBJECTIVES: to evaluate the phenotype of nucleotide excision repair in Cuban sun hypersensitive patients with clinical suspicion of xeroderma pigmentosum at erythematopigmentary phase, by using the Comet assay alkaline variant. METHODS: twenty eight patients mainly at pediatric ages were studied. The used DNA damage inducer was ultraviolet radiation C (254 nm) at 40 J/m2 dose. The DNA damage was quantified immediately after cell irradiation (0 minutes) and some time afterwards, then cultured at 37 ºC and enriched with 10 % fetal serum (45 minutes). This data allowed determining the percentage of difference in arbitrary units (AU) between both moments. RESULTS: there was no significant differences (p= 0.080976) between the group of patients (224.23 AU) and the control group (195.43 UA). The UV-C induced DNA damage was recognized and excised in the patients with similar effectiveness to that of the controls. CONCLUSIONS: the UV-C radiation-coupled alkaline comet assay allowed clearly and indirectly identifying the functioning of the nucleotide excision repair mechanisms in which XPA to XPG proteins influence. The studied subjects did not show the classical form of this disease.
Subject(s)
Humans , Sunlight/adverse effects , Ultraviolet Therapy/methods , DNA , DNA Repair/physiology , DNA Repair-Deficiency Disorders/prevention & control , Hypersensitivity/diagnosisABSTRACT
Nucleotide excision repair (NER) pathway is one of the principal ways of the repair of DNA damage.The single nucleotide polymorphisms (SNP) of its key genes such as xeroderma pigmentosum group A (XPA) gene,excision repair cross complementingl (ERCC1) gene and xeroderma pigmentosum group D (XPD) gene may be associated with differences in the DNA repair capacity and may influence an individual's risk of lung cancer,because the variant genotype in those polymorphisms might destroy or alter repair function.
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Objective:The aim of this study was to investigate the association of mRNA expressions of ERCC1 (excision repair cross-complementing group 1) and BRCA1 (breast cancer 1) with chemosensitivity to cisplatin in malignant pleural and peritoneal effusions.Methods:Malignant pleural and peritoneal effusions were collected from 46 patients diagnosed with stage Ⅳ malignant tumor, prospectively. The tumor cells were isolated and the sensitivity of tumor cells to cisplatin was detected by adenosine triphosphate-bioluminescence assay (ATP-TCA). Real-time quantitative PCR was used to determine the mRNA expressions of ERCC1 and BRCA1. Results:The expression level of ERCC1 mRNA was negatively correlated with sensitivity of non-small cell lung cancer (NSCLC) to cisplatin (P= 0.001, r=0.685). BRCA1 mRNA expression level had negative correlation with sensitivity to cisplatin in both NSCLC (P=0.014, r=0.541) and gastric cancer (P=0.002, r=0.625). A significant interaction was found between the effects of ERCC1 and BRCA1 mRNA expressions on sensitivity to cisplatin (P=0.010 for all patients;P=0.027 for gastric cancer patients).Conclusion:ERCC1 and BRCA1 mRNA expression levels correlated with ex vivo chemosensitivity of tumor cells to cisplatin in malignant pleural and peritoneal effusions. Detection of both ERCC1 and BRCA1 may have a higher reliability in predicting the sensitivity of tumor cells to cisplatin than detection of single ERCC1 or BRCA1 expression.
ABSTRACT
Xeroderma pigmentosum (XP) was first described in 1874 by Hebra and Kaposi. [1] It is a rare autosomal recessive disorder characterized by photosensitivity, pigmentary changes, premature skin aging, and malignant tumor development due to cellular hypersensitivity to ultraviolet radiation resulting from a defect in DNA repair. The basic defect in XP is in nucleotide excision repair (NER), leading to deficient repair of damaged DNA. A 12-year-old boy presented with a large growth over the right side of the forehead. The lesion was first noticed before two years as a 2 x 2 cm 2 mass. It was slowly growing and attained the present size of 10 x 8 x 7 cm 3 . The surface showed ulceration with areas of hemorrhage and blackish pigmentation. Also, the patient had hyperpigmented macules over the skin since early childhood. The macules appeared initially over the face and later developed over the other areas of the body. The macules were more over the sun exposed areas. He also had photophobia and both eyes showed corneal opacities. Histopathological examination of the excised growth showed features consistent with melanoma. This case is being presented because of its rare association with xeroderma pigmentosum patients in India.
ABSTRACT
In general, stochastic tumors show genomic instability associated with the proliferation of DNA point mutations, that is, a mutator phenotype. This feature cannot be explained by a dysfunctional mismatch repair alone, and indicates that nucleotide excision repair (NER) and/or base excision repair should be suppressed. However, mutations in NER genes are not causally implicated in the oncogenesis of sporadic solid tumors, according to the Cancer Gene Census at http://www.sanger.ac.uk/genetics/CGP/Census/. This brings up an apparent paradox: how to explain the recurrent non-existence in NER genes of somatic mutations causally related to cancer? In a recent study, we have shown that the origin of point mutations in cancer cell genomes can be explained by a structurally conserved NER with a functional disorder generated from its entanglement with a disabled apoptosis gene network. In the present study, we further characterize NER gene network properties and show that it has a highly connected architecture. This feature suggests that the absence of mutations in NER genes in sporadic solid tumors is a result of their participation in many essential cellular functions.
Subject(s)
Humans , Gene Regulatory Networks , Neoplasms/genetics , Point Mutation , DNA Repair/genetics , Apoptosis/genetics , Genomic InstabilityABSTRACT
The p53 tumor suppressor has long been envisaged to preserve genetic stability by the induction of cell cycle checkpoints and apoptosis. More recently, p53 has been implicated to play roles in DNA repair responses to genotoxic stresses. UV-damage and the damage caused by certain chemotherapeutics including cisplatin and nitrogen mustards are known to be repaired by the nucleotide excision repair (NER) pathway which is reportedly regulated by p53 and its downstream genes. There are evidences to suggest that the base excision repair (BER) induced by the base-damaging agent methyl methanesulfonate (MMS) is partially deficient in cells lacking functional p53. This result suggests that the activity of BER might be also dependent on the p53 status. In this review, we discuss the possibilities that p53 regulates BER as well as NER; these are one of the most significant potentials of p53 tumor suppressor for repairing the vast majority of DNA damages that is incurred from various environmental stresses.
Subject(s)
Animals , Humans , Mice , Antineoplastic Agents/pharmacology , DNA/drug effects , DNA Damage , DNA Repair/physiology , Tumor Suppressor Protein p53/physiologyABSTRACT
PURPOSE: The expressions of low levels of ERCC1 (excision repair crosscomplementation group 1) and ERCC2/XPD (excision repair cross- complementation group 2) have been studied in order to find a potential marker for predicting the prognosis or treatment response in cancer patients. However, polymorphisms in these genes have been rarely evaluated in terms of predicting the survival of cancer patients. MATERIALS AND METHODS: We investigated whether these polymorphisms had an effect on the response to chemotherapy and on the survival in 109 patients, with non-small-cell lung cancer, treated with cisplatin plus gemcitabine, paclitaxel or docetaxel. The polymorphisms of ERCC1 Asn118Asn (C->T), ERCC2 Lys751Gln and Asp312Asn were evaluated using a SNaPshot kit. RESULTS: The treatment responses showed no statistically significant differences according to the polymorphisms of ERCC1 Asn118Asn, ERCC2 Lys751Gln or Asp312Asn. The median survival time was 376 days (95% CI, 291~488). The overall survival rate showed no significant difference according to age, sex, chemotherapy regimen, clinical stage or sequential radiation therapy. The polymorphisms of ERCC2 Lys751Gln and Asp312Asn did not affect the survival of the patients (p=0.4711 and 0.4542, respectively). The polymorphism of ERCC1 Asn118Asn, chemotherapy response, performance status and body weight loss had effect on the overall survival of the patients (p=0.0001, 0.0001, 0.0176 and 0.0082 respectively). As for survival rate, according to the polymorphism in ERCC1 Asn118Asn, the median survival time in those patients showing the wild genotype (C/C) was 480 days (95% CI, 333~544), which was statistically significant compared with the 281 days for the patients with the variant genotype (T/T, C/T) (hazard ratio 3.497) (95% CI, 214~376). CONCLUSION: It is suggested that the presence of the wild genotype in ERCC1 Asn118Asn, in non-small-cell lung cancer patients treated with cisplatin based chemotherapy, was a surrogate marker for predicting a better survival.
Subject(s)
Humans , Biomarkers , Body Weight , Cisplatin , Complement System Proteins , DNA Repair , Drug Therapy , Genotype , Lung Neoplasms , Lung , Paclitaxel , Prognosis , Survival RateABSTRACT
Due to the high incidence and mortality of digestive system malignant tumor,so it is of great significance to make further research for digestive tract tumor.Platinum drugs,one of the traditional drugs which is used for the chemotherapy for digestive system tumor,which has been extensively applied to the chemotherapy for malignant tumor.However,the resistance to the drugs exerts a serious influence on its curative effect.At present,it is believed that the nucleotide excision repair(NER)constitutes one of the most important mechanisms which results in the resistance to platinum drugs,mainly because it causes the twisting of DNA helix by removing large numbers of platinum compounds.The nucleotide excision repair cross complementation group 1(ERCC1)plays an important role in the process of NER.The different expression of ERCC1 in peripheral blood and tumor tissue of patients with digestive sysem tumor has a close connection with therapeutic effect of the platinum-containing chemotherapy.This article aims to provide an overview of the relation between the ERCC1 research development and the curative effect of cisplatin chemotherapy for digestive system tumor.
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Objective To study the effect of benzo(a) pyrene on DNA of human embryonic fibroblast under inhibition of DNA repair,and to explore the mechanism of DNA repair involved in the DNA damage induced by xenobiotic chemical carcinogens. Methods DNA damage of human embryonic lung fibroblast (HELF) induced by benzo(a) pyrene was observed when DNA repair was inhibited by treating HELF with arabinosylcytosin(ara-C) to inhibit the activity of polymerase ?/? in the cells. With S9 mixture added as metabolic activation system in vitro,HELF was treated for 2 hours with ara-C at the doses of 0 and 100 ?mol/L combined with-C at the doses of 0,10,20,50 ?mol/L by the 2?4 factor-factorial analysis.Comet assay was used to assess the DNA damage. Results Compared with the control group,the comet rate and Oliver tail moment of groups treated by B(a)P increased significantly (P