(5′S)-8,5′-Cyclo-2′-deoxyguanosine Is a Strong Block to Replication, a Potent pol V-Dependent Mutagenic Lesion, and Is Inefficiently Repaired in Escherichia coli

8,5′-Cyclopurines, making up an important class of ionizing radiation-induced tandem DNA damage, are repaired only by nucleotide excision repair (NER). They accumulate in NER-impaired cells, as in Cockayne syndrome group B and certain Xeroderma Pigmentosum patients. A plasmid containing (5′S)-8,5′-cyclo-2′-deoxyguanosine (S-cdG) was replicated in Escherichia coli with specific DNA polymerase knockouts. Viability was \u3c1% in the wild-type strain, which increased to 5.5% with SOS. Viability decreased further in a pol II- strain, whereas it increased considerably in a pol IV- strain. Remarkably, no progeny was recovered from a pol V- strain, indicating that pol V is absolutely required for bypassing S-cdG. Progeny analyses indicated that S-cdG is significantly mutagenic, inducing ∼34% mutation with SOS. Most mutations were S-cdG → A mutations, though S-cdG → T mutation and deletion of 5′C also occurred. Incisions of purified UvrABC nuclease on S-cdG, S-cdA, and C8-dG-AP on a duplex 51-mer showed that the incision rates are C8-dG-AP \u3e S-cdA \u3e S-cdG. In summary, S-cdG is a major block to DNA replication, highly mutagenic, and repaired slowly in E. coli

Structures of (5′S)-8,5′-Cyclo-2′-deoxyguanosine Mismatched with dA or dT

pubs.acs.org/cr

Risk Prediction Scores for Recurrence and Progression of Non-Muscle Invasive Bladder Cancer: An International Validation in Primary Tumours

Abstract Objective: We aimed to determine the validity of two risk scores for patients with non-muscle invasive bladder cancer in different European settings, in patients with primary tumours. Methods: We included 1,892 patients with primary stage Ta or T1 non-muscle invasive bladder cancer who underwent a transurethral resection in Spain (n = 973), the Netherlands (n = 639), or Denmark (n = 280). We evaluated recurrence-free survival and progression-free survival according to the European Organisation for Research and Treatment of Cancer (EORTC) and the Spanish Urological Club for Oncological Treatment (CUETO) risk scores for each patient and used the concordance index (c-index) to indicate discriminative ability. Results: The 3 cohorts were comparable according to age and sex, but patients from Denmark had a larger proportion of patients with the high stage and grade at diagnosis (p,0.01). At least one recurrence occurred in 839 (44%) patients and 258 (14%) patients had a progression during a median follow-up of 74 months. Patients from Denmark had the highest 10- year recurrence and progression rates (75% and 24%, respectively), whereas patients from Spain had the lowest rates (34% and 10%, respectively). The EORTC and CUETO risk scores both predicted progression better than recurrence with c-indices ranging from 0.72 to 0.82 while for recurrence, those ranged from 0.55 to 0.61. Conclusion: The EORTC and CUETO risk scores can reasonably predict progression, while prediction of recurrence is more difficult. New prognostic markers are needed to better predict recurrence of tumours in primary non-muscle invasive bladder cancer patients.This research received funding from the European Community's Seventh Framework program FP7/2007-2011 under grant agreement 201663 (Uromol project, http://www.uromol.eu/

Expression and biological-clinical significance of hTR, hTERT and CKS2 in washing fluids of patients with bladder cancer

<p>Abstract</p> <p>Background</p> <p>at present, pathogenesis of bladder cancer (BC) has not been fully elucidated. Aim of this study is to investigate the role of human telomerase RNA (<it>hTR</it>), human telomerase reverse transcriptase (<it>hTERT</it>) and CDC28 protein kinase regulatory subunit 2 (<it>CKS2</it>) in bladder carcinogenesis and their possible clinical significance;</p> <p>Methods</p> <p>the transcript levels of <it>hTR</it>, <it>hTERT </it>and <it>CKS2 </it>were quantified by Real time reverse transcriptase chain reaction in exfoliated cells from bladder washings of 36 patients with BC and 58 controls. The statistical significance of differences between BC bearing patients and control groups, in the general as well as in the stratified analysis (superficial or invasive BC), was assessed by Student's t test. Non parametric Receiver Operating Characteristics analysis (ROC) was performed to ascertain the accuracy of study variables to discriminate between BC and controls. The clinical value of concomitant examination of <it>hTR</it>, <it>hTERT </it>and <it>CKS2 </it>was evaluated by logistic regression analysis;</p> <p>Results</p> <p>a significant decrease in <it>hTR </it>and a significant increase in <it>hTERT </it>or <it>CKS2 </it>gene expression were found between BC bearing patients and controls, as well as in the subgroups analysis. The area under the curve (AUC) indicated an average discrimination power for the three genes, both in the general and subgroups analysis, when singularly considered. The ability to significantly discriminate between superficial and invasive BC was observed only for <it>hTR </it>transcript levels. A combined model including <it>hTR </it>and <it>CKS2 </it>was the best one in BC diagnosis;</p> <p>Conclusions</p> <p>our results, obtained from a sample set particularly rich of exfoliated cells, provide further molecular evidence on the involvement of <it>hTR, hTERT </it>and <it>CKS2 </it>gene expression in BC carcinogenesis. In particular, while <it>hTERT </it>and <it>CKS2 </it>gene expression seems to have a major involvement in the early stages of the disease, <it>hTR </it>gene expression, seems to be more involved in progression. In addition, our findings suggest that the studied genes have a clinical role in discriminating between BC and controls in the general as well as in the stratified analysis, when singularly considered. A combined model improved over the single marker BC diagnosis.</p

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

Background: Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. Design: A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Results: Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. Conclusions: This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified