5-Aza-2′-deoxycytidine (5azaC-dR) has been employed as an inhibitor of DNA methylation, a chemotherapeutic agent, a clastogen, a mutagen, an inducer of fragile sites and a carcinogen. However, its effects are difficult to quantify because it rapidly breaks down in aqueous solution to the stable compound 2′-deoxyriboguanylurea (GuaUre-dR). Here, we used a phosphoramidite that permits the introduction of GuaUre-dR at defined positions in synthetic oligodeoxynucleotides to demonstrate that it is a potent inhibitor of human DNA methyltransferase 1 (hDNMT1) and the bacterial DNA methyltransferase (M.EcoRII) and that it is a mutagen that can form productive base pairs with either Guanine or Cytosine. Pure GuaUre-dR was found to be an effective demethylating agent and was able to induce 5azaC-dR type fragile sites FRA1J and FRA9E in human cells. Moreover, we report that demethylation associated with C:G → G:C transversion and C:G → T:A transition mutations was observed in human cells exposed to pure GuaUre-dR. The data suggest that most of the effects attributed to 5azaC-dR are exhibited by its stable primary breakdown product.

Purpose Active surveillance (AS) is a viable patient option for prostate cancer where a clinical determination of low-risk and presumably organ-confined disease can be made. In an effort to standardize risk stratification schemes, the National Comprehensive Cancer Network (NCCN) has provided guidelines for the AS option. Our purpose was to determine the effectiveness of expressed prostatic secretion (EPS) biomarkers in detecting occult risk factors in NCCN AS candidates. Materials and Methods EPS specimens were obtained prior to Robot-Assisted Radical Prostatectomy (RARP). Secretion capacity biomarkers: total RNA and EPS specimen volume were measured by standard techniques. RNA expression biomarkers: TXNRD1-mRNA, PSA-mRNA, TMPRSS2:ERG fusion mRNA and PCA3-mRNAs were measured by quantitative reverse-transcription PCR. Results Of the 528 patients from whom EPS was collected, 216 were eligible for AS under NCCN guidelines. Variable Selection in logistic regression identified two models, one featuring Type III and Type VI TMPRSS2:ERG variants, and one featuring two secretion capacity biomarkers. Of the two high performing models, the secretion capacity model was the most effective in detecting patients within this group that were upstaged or both upstaged and upgraded. It reduced the risk of upstaging in patients with a negative test by nearly 8 fold, and reduced the risk of being both upstaged and upgraded by about 5 fold, while doubling the prevalence upstaging in the positive test group. Conclusions Non-invasive EPS testing may improve patient acceptance of AS by dramatically reducing the presence of occult risk factors among patients eligible for AS under NCCN guidelines.

Histological staining of reactive stroma has been shown to be a predictor of biochemical recurrence in prostate cancer, however, molecular markers of the stromal response to prostate cancer have not yet been fully delineated. The objective of this study was to determine whether or not the stromal biomarkers detected with a thioredoxin-targeted nanodevice could be used to distinguish the stroma associated with benign prostatic hyperplasia from that associated with PCA. In this regard, we recently demonstrated that a thioredoxin-targeted nanodevice selectively binds to reactive stroma in frozen prostate tumor tissue sections. To accomplish this, random frozen prostate tissue sections from each of 35 patients who underwent resection were incubated with the nanodevice and graded for fluorescent intensity. An adjacent section from each case was stained with Hematoxylin & Eosin to confirm the diagnosis. Select cases were stained with Masson's Trichrome or immunohistochemically using antibodies to thioredoxin reductase 1, thioredoxin reductase 2 or peroxiredoxin 1. Our results demonstrate that the graded intensity of nanodevice binding to the stroma associated with PCA was significantly higher (p = 0.0127) than that of benign prostatic hyperplasia using the t-test. Immunohistochemical staining of adjacent sections in representative cases showed that none of the two commonly studied thioredoxin interacting protein partners mirrored the fluorescence pattern seen with the nanodevice. However, thioredoxin reductase 2 protein was clearly shown to be a biomarker of prostate cancer-associated reactive stroma whose presence distinguishes the stroma associated with benign prostatic hyperplasia from that associated with prostate cancer. We conclude that the signal detected by the nanodevice, in contrast to individual targets detected with antibodies used in this study, originates from multiple thioredoxin interacting protein partners that distinguish the M2 neutrophil and macrophage associated inflammatory response in prostate cancer-associated stroma from the CD4+ T-Lymphocyte linked inflammation in benign prostatic hyperplasia.

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