8-hydroxy-2--deoxyguanosine and Chromosome-Deletion

Malignant mesothelioma is an aggressive and therapy-resistant neoplasm arising from mesothelial cells. Evidence suggests that the major pathology associated with asbestos-induced mesothelioma is local iron overload. In the present study, we induced iron-induced mesothelioma in rats based on previous reports. Ten Wistar rats were given ferric saccharate and nitrilotriacetate i.p. for 5 days a week. Five of the ten rats exhibited widespread mesotheliomas in the peritoneum and tunica vaginalis. The tumor cells showed positive immunostaining for calretinin, wilms tumor-1, podoplanin and the oxidative DNA marker 8-hydroxy-2'-deoxyguanosine. In three of the five rats with mesothelioma, array-based comparative genomic hybridization analysis identified a common chromosomal deletion mapped to the chromosomal 4q31 locus, which encompasses the TBXAS1 gene. Downregulation of the TBXAS1 gene was confirmed using quantitative PCR. TBXAS1 gene expression was also reduced in three of four human malignant pleural mesothelioma cell lines compared with normal bronchial epithelial cells. Immunohistochemistry revealed that TBXAS1 expression was weakly positive and positive in five and three out of eight human malignant mesothelioma samples, respectively. In conclusion, TBXAS1 gene expression was downregulated in rats with iron-induced mesothelioma. The relationship between iron overload and TBXAS1 downregulation should be pursued further.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Biomarkers, Tumor; Calbindin 2; Cell Cycle Proteins; Cell Line, Tumor; Chromosome Deletion; Deoxyguanosine; Down-Regulation; Ferric Compounds; Ferric Oxide, Saccharated; Glucaric Acid; Humans; Iron; Iron Overload; Lung Neoplasms; Male; Membrane Glycoproteins; Mesothelioma; Mesothelioma, Malignant; Neoplasms, Experimental; Nuclear Proteins; Rats; Rats, Wistar; RNA Splicing Factors; Thromboxane-A Synthase

We examined oxidative damage to leukocyte DNA in the spermatic vein and sperm DNA of patients with varicocele.. A total of 32 young male patients with varicocele (group 1), 20 young male patients with subclinical varicocele (group 2) and 15 normal young males without varicocele (group 3) were recruited in this study. Varicocele and subclinical varicocele were confirmed by physical examination and Doppler ultrasonography. Blood samples were drawn from peripheral and spermatic veins of controls and patients before varicocelectomy. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) in leukocyte DNA and sperm DNA were measured by high performance liquid chromatography. The 4977 bp deletion of mitochondrial DNA (mtDNA) in spermatozoa was detected by polymerase chain reaction.. The mean 8-OHdG level +/- SD in leukocyte DNA of spermatic veins was significantly higher than that of corresponding peripheral veins in groups 1 and 2 (12.39 +/- 2.90 vs 7.11 +/- 0.75/10 deoxyguanosine for group 1 and 10.28 +/- 2.43 vs 6.82 +/- 0.62/10 deoxyguanosine for group 2, p <0.001). The 8-OHdG level in leukocyte DNA of the spermatic vein and 8-OHdG in sperm DNA were highest in group 1 followed by those in groups 2 and 3, and correlated inversely with motility, morphology and density of spermatozoa. The incidence of 4977 bp deletion of mtDNA in sperm was 40.6%, 20% and 0% in groups 1, 2 and 3, respectively. These results indicate that oxidative stress in patients with varicocele or subclinical varicocele was greater than in healthy subjects.. 8-OHdG in leukocyte DNA of the spermatic vein and in sperm DNA, and 4977 bp deletion of mtDNA in sperm might be useful markers for the assessment of oxidative stress in patients with varicocele and subclinical varicocele.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Chromosome Deletion; Deoxyguanosine; DNA; DNA, Mitochondrial; Humans; Infertility, Male; Leukocytes; Male; Oxidative Stress; Palpation; Predictive Value of Tests; Reference Values; Sperm Count; Sperm Motility; Spermatic Cord; Spermatozoa; Ultrasonography, Doppler; Varicocele; Veins

This is the first report that age-associated accumulation of 8-hydroxydeoxyguanosine (8-OH-dG) does occur in human mitochondrial DNA (mtDNA) in muscle of diaphragm. We extracted mtDNA from human diaphragm muscles from differing age groups, and determined the amount of 8-OH-dG by ultramicro-high performance liquid chromatography/mass-spectrometry system. With the same specimen, multiple deletions of mtDNA were detected by electrophoresis after amplification by the polymerase chain reaction method. In subjects below age 55, the level of 8-OH-dG in mtDNA was below 0.02% of the total deoxyguanosine (dG), whereas, in subjects over age 65, the level of 8-OH-dG increased with age at a rate of ca. 0.25% per 10 years, reaching 0.51% at age 85. Moreover, a concomitant increase in multiple deletions was detected with the increase in age. These results suggest that, in younger diaphragms, replication of mtDNA dilutes out 8-OH-dG being not detectable. In the elderly subjects aged over 65, the replication rate might be slowed down leading to the accumulation of 8-OH-dG in mtDNA, which would accelerate the age-associated multiple deletions of mtDNA observed among the subjects.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aged, 80 and over; Aging; Chromatography, High Pressure Liquid; Chromosome Deletion; Deoxyguanosine; Diaphragm; DNA Replication; DNA, Mitochondrial; Electrophoresis, Polyacrylamide Gel; Gas Chromatography-Mass Spectrometry; Humans; Male; Middle Aged; Polymerase Chain Reaction