Multi-Institutional Study of Dorsal Onlay Urethroplasty of the Membranous Urethra after Endoscopic Prostate Procedures: Operative Results, Continence, Erectile Function and Patient Reported Outcomes.

(1) Background: To critically evaluate dorsal onlay buccal mucosal graft urethroplasty (DOBMGU) for posterior urethral stenosis repair following transurethral resection and other endoscopic prostate procedures. (2) Methods: A retrospective multi-institutional review of patients with membranous or bulbomembranous urethral stenosis for whom treatment with DOBMGU was conducted after receipt of prostate endoscopic procedures. Baseline data, peri-operative care, post-operative care and patient-reported outcomes were analyzed. The primary outcomes were procedural failure and development of de novo stress urinary incontinence (SUI). The secondary outcomes were changes in voiding, sexual function and patient satisfaction. (3) Results: A total of 107 men with a mean age of 69 ± 9.5 years and stenosis length of 3.5 ± 1.8 cm were included. Prior endoscopic procedures among participants were 47 patients (44%) with monopolar TURP, 33 (30.8%) with bipolar TURP, 16 (15%) with Greenlight laser, 9 (8.4%) with Holmium laser enucleation and 2 (1.9%) with bladder neck incision. At a mean follow-up time of 59.3 ± 45.1 months, stenosis recurred in 10 patients (9.35%). Multivariate analysis confirmed that postoperative complications (OR 12.5; p = 0.009), history of radiation (OR 8.3; p = 0.016) and ≥2 dilatations before urethroplasty (OR 8.3; p = 0.032) were independent predictors of recurrence. Only one patient (0.9%) developed de novo SUI. Patients experienced significant improvement in PVR (128 to 60 cc; p = 0.001), Uroflow (6.2 to 16.8 cc/s; p = 0.001), SHIM (11.5 to 11.7; p = 0.028), IPSS (20 to 7.7; p < 0.001) and QoL (4.4 to 1.7; p < 0.001), and 87 cases (81.3%) reported a GRA of + 2 or better. (4) Conclusions: DOBMGU is an effective and safe option for patients with posterior urethral stenosis following TURP and other prostate endoscopic procedures. This non-transecting approach minimizes external urinary sphincter manipulation, thus limiting postoperative risk of SUI or erectile dysfunction.

Pyrido[2,3-b][1,5]benzoxazepin-5(6H)-one derivatives as CDK8 inhibitors.

CDK8 is a cyclin-dependent kinase that forms part of the mediator complex, and modulates the transcriptional output from distinct transcription factors involved in oncogenic control. Overexpression of CDK8 has been observed in various cancers, representing a potential target for developing novel CDK8 inhibitors in cancer therapeutics. In the course of our investigations to discover new CDK8 inhibitors, we designed and synthesized tricyclic pyrido[2,3-b][1,5]benzoxazepin-5(6H)-one derivatives, by introduction of chemical complexity in the multi-kinase inhibitor Sorafenib taking into account the flexibility of the P-loop motif of CDK8 protein observed after analysis of structural information of co-crystallized CDK8 inhibitors. In vitro evaluation of the inhibitory activity of the prepared compounds against CDK8 led us to identify compound 2 as the most potent inhibitor of the series (IC50 = 8.25 nM). Co-crystal studies and the remarkable selectivity profile of compound 2 are presented. Compound 2 showed moderate reduction of phosphorylation of CDK8 substrate STAT1 in cells, in line with other reported Type II CDK8 inhibitors. We propose herein an alternative to find a potential therapeutic use for this chemical series.

Molecular Architecture of Full-length TRF1 Favors Its Interaction with DNA.

Telomeres are specific DNA-protein structures found at both ends of eukaryotic chromosomes that protect the genome from degradation and from being recognized as double-stranded breaks. In vertebrates, telomeres are composed of tandem repeats of the TTAGGG sequence that are bound by a six-subunit complex called shelterin. Molecular mechanisms of telomere functions remain unknown in large part due to lack of structural data on shelterins, shelterin complex, and its interaction with the telomeric DNA repeats. TRF1 is one of the best studied shelterin components; however, the molecular architecture of the full-length protein remains unknown. We have used single-particle electron microscopy to elucidate the structure of TRF1 and its interaction with telomeric DNA sequence. Our results demonstrate that full-length TRF1 presents a molecular architecture that assists its interaction with telometic DNA and at the same time makes TRFH domains accessible to other TRF1 binding partners. Furthermore, our studies suggest hypothetical models on how other proteins as TIN2 and tankyrase contribute to regulate TRF1 function.

Molecular architecture of the recombinant human MCM2-7 helicase in complex with nucleotides and DNA.

DNA replication is a key biological process that involves different protein complexes whose assembly is rigorously regulated in a successive order. One of these complexes is a replicative hexameric helicase, the MCM complex, which is essential for the initiation and elongation phases of replication. After the assembly of a double heterohexameric MCM2-7 complex at replication origins in G1, the 2 heterohexamers separate from each other and associate with Cdc45 and GINS proteins in a CMG complex that is capable of unwinding dsDNA during S phase. Here, we have reconstituted and characterized the purified human MCM2-7 (hMCM2-7) hexameric complex by co-expression of its 6 different subunits in insect cells. The conformational variability of the complex has been analyzed by single particle electron microscopy in the presence of different nucleotide analogs and DNA. The interaction with nucleotide stabilizes the complex while DNA introduces conformational changes in the hexamer inducing a cylindrical shape. Our studies suggest that the assembly of GINS and Cdc45 to the hMCM2-7 hexamer would favor conformational changes on the hexamer bound to ssDNA shifting the cylindrical shape of the complex into a right-handed spiral conformation as observed in the CMG complex bound to DNA.