The etiology and prediction of breast cancer. Fourier transform-infrared spectroscopy reveals progressive alterations in breast DNA leading to a cancer-like phenotype in a high proportion of normal women

Polissar

Ostrander

et al. 2000

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Structural changes in a 25-base DNA strand, induced by single 8-oxo-guanine or 8-oxo-adenine substitutions, were shown by using Fourier transform-infrared spectroscopy with multivariate statistics. Pronounced differences were demonstrated between the parent and derivatives with respect to base interactions and changes in the phospho-deoxyribose backbone. The greatest degree of change in the backbone likely occurred immediately adjacent to the 8-oxo group, potentially altering the stereochemistry at a distance. The 8-oxo lesions, formed from reactive oxygen species (e.g., hydroxyl radicals), may appreciably alter the conformational properties of strands at the replication fork, thus affecting the selectivity of polymerases, the proofreading capability of repair enzymes, and the fidelity of the transcriptional machinery.Fourier transform-infrared spectroscopy ͉ DNA transcription ͉ DNA replication ͉ DNA repair ͉ DNA polymerases

mentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Single 8-oxo-guanine and 8-oxo-adenine lesions induce marked changes in the backbone structure of a 25-base DNA strand

Polissar

Ostrander

et al. 2000

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“…It has been estimated that the rate of attack of the ⅐OH on the nucleotide bases is about five times that for deoxyribose (22). Also, the DNAs from normal (RMT) tissue and metastatic tumor tissue have been shown to have substantial structural diversity (4,5), at least partly as a result of ⅐OH-induced modifications in the nucleotide bases and the phosphodiester-deoxyribose structure. Such diverse populations of DNA likely provide a basis for the selection of subgroups of highly malignant phenotypes with modified base structures and virtually no impairment of deoxyribose.…”

Section: Discussionmentioning

confidence: 99%

“…A significant body of evidence points to the involvement of the hydroxyl radical (⅐OH) in introducing mutagenic structures into DNA of the normal female breast, thus statistically increasing the probability of breast cancer (1)(2)(3)(4)(5). In a recent study (5), the transformation of primary breast tumors to the metastatic state was shown to involve a Ͼ2-fold increase in ⅐OH damage in DNA, as indicated by modified nucleotide base models comprising mutagenic 8-hydroxyadenine (6) and the putatively nonmutagenic ring-opened product 4,6-diamino-5-formamidopyrimidine (fapyadenine; refs.…”

mentioning

confidence: 99%

Tumor progression to the metastatic state involves structural modifications in DNA markedly different from those associated with primary tumor formation

Polissar

Gunselman

1996

Wavenumber-absorbance relationships of infrared spectra of DNA analyzed by principal components analysis may be expressed as points in space. Each point represents a highly discriminating measure of DNA structure. Structural modifications of DNA, such as those induced by free radicals, alter vibrational and rotational motion and consequently change the spatial location of the points. Using this technology to analyze breast tumor DNA, we revealed a 94؇ difference in direction between the progression of normal DNA 3 primary tumor DNA and the progression of primary tumor DNA 3 metastatic tumor DNA (P < 0.001). This sharp directional change was accompanied by a substantial increase in the structural diversity of the metastatic tumor DNA (P ‫؍‬ 0.003), which, on the basis of the volume of the core cluster of points, could comprise as many as 11 ؋ 10 9 different phenotypes. This suggests that the heterogeneity and varied physiological properties known to characterize malignant tumor cell populations may at least partially arise from these diverse phenotypes. The evidence suggests that the progression to the metastatic state involves structural modifications in DNA that are markedly different from the modifications associated with the formation of the primary tumor. Overall, the findings of this and earlier studies imply that the observed DNA alterations are a pivotal factor in the etiology of breast cancer and a formidable barrier to overcome in intervention to control the disease. In terms of cancer etiology and prediction, the technology described has potentially wide application to studies in which the structural status of DNA is an important consideration.A significant body of evidence points to the involvement of the hydroxyl radical (⅐OH) in introducing mutagenic structures into DNA of the normal female breast, thus statistically increasing the probability of breast cancer (1-5). In a recent study (5), the transformation of primary breast tumors to the metastatic state was shown to involve a Ͼ2-fold increase in ⅐OH damage in DNA, as indicated by modified nucleotide base models comprising mutagenic 8-hydroxyadenine (6) and the putatively nonmutagenic ring-opened product 4,6-diamino-5-formamidopyrimidine (fapyadenine; refs. 7-11). In addition, plots of the modified nucleotide base model log 10 (fapyadenine͞8-hydroxyadenine) versus the size of metastatic and nonmetastatic breast tumors revealed that the metastatic tumor DNA had significantly greater structural diversity than the nonmetastatic tumor DNA (P ϭ 0.01; ref. 5).Principal components analysis (PCA) of data obtained by Fourier transform-infrared (FT-IR) spectroscopy yielded plots in which individual spectra were represented as points in twoor three-dimensional space. Each point was a highly discriminating representation of an individual DNA structure in that spatially and visually close points had Ͻ3% average spectral difference over the range 1750-700 cm Ϫ1 (5). The core cluster of metastatic tumor DNA points was substantially larger than the core c...

“…PCs analysis was performed on the mean spectrum of each sample, resulting in 10 PC scores per sample (22,23). Significant differences in the PC scores between tissue groups were determined by using t tests (Table 1).…”

Section: Gc-msmentioning

confidence: 99%

Cancer-related changes in prostate DNA as men age and early identification of metastasis in primary prostate tumors

Johnson

Barker

et al. 2003

Self Cite

113

Using statistical analyses of Fourier transform-IR spectra, we show that DNA of the histologically normal prostates of men 16 -80 years old undergoes structural changes in the bases and backbone with increasing age. Of the older men (ages 55-80), 42% exhibited a DNA phenotype mimicking that of primary prostate tumors from a comparable age group. This cancer-like phenotype, which was not found in the younger men (ages 16 -36), appears to arise from progressive age-related damage to DNA. The mean concentrations of 8-hydroxypurine lesions (e.g., 8-hydroxyguanine) were substantially higher for the older men than for the younger men. This finding suggests that the hydroxyl radical contributed to the structural changes that characterize the cancer-like phenotype. Strikingly, we were additionally able to discriminate between the DNA of primary prostate tumors and the DNA of primary prostate tumors from which distant metastases had been identified. Moreover, logistic regression analysis was able to predict the probability that a tumor had metastasized with Ϸ90% sensitivity and specificity. Collectively, these findings are particularly promising for identifying men at risk for developing prostate cancer, as well as for the early determination of whether a primary tumor has progressed to the metastatic state. This is highly important because the prognosis of histologically similar prostate carcinomas varies, thus creating a need to predict which cancers are most likely metastatic.I n the United States, prostate cancer is the most prevalent of all cancers and the second-leading cause of cancer mortality in men (1). The incidence rates for this disease rise markedly as a function of increasing age (1-3). Notably, 70% of all newly diagnosed prostate cancers occur in men over age 65 (2). The greatest threat from prostate cancer lies in its potential to metastasize (3). Clinical diagnosis of metastatic prostate cancer presently depends on histological identification of distant metastases. Yet, by the time the tumor has metastasized, the success of intervention is severely limited. Clearly, there is a need to identify early subcellular changes in the prostate, such as in DNA, associated with aging, primary tumor development, and the progression to metastasis.We have reported (4) that the ratio of mutagenic 8-hydroxy to putatively nonmutagenic ring-opened purine lesions in prostate DNA increased Ϸ3-fold in men between the ages of 16 and 83. In addition, a related study (5) showed a substantial accumulation of 8-hydroxyguanine (8-OH-Gua) in the liver, kidney, and intestine as rats aged. It was later reported (6) that levels of this base lesion increased 186% in the livers of rats between 5 and 30 months. Several factors have been suggested to explain agerelated increases in DNA base lesion concentrations in various tissues, among them reduced enzyme repair (7-10), a slow loss of DNA nuclease activity (5), and an increase in base oxidation (11). These findings focus attention on the importance of age-related free radical damage to...