Can Contemporary Patients with Biopsy Gleason Score 3+4 Be Eligible for Active Surveillance?

Introduction

We analyzed whether expansion of existing active surveillance (AS) protocols to include men with biopsy Gleason score (GS) 3+4 prostate cancer (PCa) would significantly alter pathologic and biochemical outcomes of potential candidates of AS.

Methods

Among patients who underwent radical prostatectomy at our center between 2006 and 2013, we identified 577 patients (group A) who preoperatively fulfilled at least one of 6 different AS criteria. Also, we identified 217 patients (group B) with biopsy GS 3+4 but fulfilled non-GS criteria from at least one of 6 AS criteria. Designating group C as expanded group incorporating all patients in group A and B, we compared risk of unfavorable disease (pathologic GS ≥4+3 and/or pathologic T stage ≥pT3a) and biochemical recurrence (BCR)-free survival between groups.

Results

Rates of unfavorable disease were not significantly different between patients of group A and C who met AS criteria from 5 institutions (all p>0.05), not including University of Toronto (p<0.001). Also BCR-free survivals were not significantly different between patients in group A and C meeting each of 6 AS criteria (all p>0.05). Among group B, PSAD>0.15 ng/mL/cm³ (p = 0.011) and tumor length of biopsy GS 3+4 core>4 mm (p = 0.007) were significant predictors of unfavorable disease. When these two criteria were newly applied in defining group B, rates of unfavorable disease in group A and B was 15.6% and 14.7%, respectively (p = 0.886).

Conclusion

Overall rate of pathologically aggressive PCa harbored by potential candidates for AS may not be increased significantly with expansion of criteria to biopsy GS 3+4 under most contemporary AS protocols. PSAD and tumor length of biopsy GS 3+4 core may be useful predictors of more aggressive disease among potential candidates for AS with biopsy GS 3+4.     

Repression of transcriptional activity of estrogen receptor alpha by a Cullin3/SPOP ubiquitin E3 ligase complex

The role of SPOP in the ubiquitination of ER alpha by the Cullin3-based E3 ubiquitin ligase complex was investigated. We showed that the N-terminal region of SPOP containing the MATH domain interacts with the AF-2 domain of ER alpha in cultured human embryonic 293 cells. SPOP was required for coimmunoprecipitation of ER alpha; with Cullin3. This is the first report of the essential role of SPOP in ERalpha ubiquitination by the Cullin3-based E3 ubiquitin ligase complex. We also demonstrated repression of the transactivation capability of ER alpha; in cultured mammalian cells.     

Enhanced production and secretion of streptokinase into extracellular medium in Escherichia coli by removal of 13 N-terminal amino acids

The production and secretion of streptokinase using OmpA signal sequence in E. coli was enhanced by removing the 13 N-terminal amino acids (SK(N13). The secretion level of SK(N13 protein into the extracellular medium was two times higher than that of wild-type streptokinase. About 4500 IU of SK(N13 protein per 1 ml LB-ampicillin medium was secreted into extracellular medium at 12 hours after induction. Fully active and enhanced extracellular preparation of the mutant streptokinase may be a potential alternative source for the simple downstream processing     

Effects of particulate matter exposure on blood 5-hydroxymethylation: results from the Beijing truck driver air pollution study

Previous studies have reported epigenetic changes induced by environmental exposures. However, previous investigations did not distinguish 5-methylcytosine (5mC) from a similar oxidative form with opposite functions, 5-hydroxymethylcytosine (5hmC). Here, we measured blood DNA global 5mC and 5hmC by ELISA and used adjusted mixed-effects regression models to evaluate the effects of ambient PM₁₀ and personal PM_2.5 and its elemental components—black carbon (BC), aluminum (Al), calcium (Ca), potassium (K), iron (Fe), sulfur (S), silicon (Si), titanium (Ti), and zinc (Zn)—on blood global 5mC and 5hmC levels. The study was conducted in 60 truck drivers and 60 office workers in Beijing, China from The Beijing Truck Driver Air Pollution Study at 2 exams separated by one to 2 weeks. Blood 5hmC level (0.08%) was ∼83-fold lower than 5mC (6.61%). An inter-quartile range (IQR) increase in same-day PM₁₀ was associated with increases in 5hmC of 26.1% in office workers (P = 0.004), 20.2% in truck drivers (P = 0.014), and 21.9% in all participants combined (P < 0.001). PM₁₀ effects on 5hmC were increasingly stronger when averaged over 4, 7, and 14 d preceding assessment (up to 132.6% for the 14-d average in all participants, P < 0.001). PM₁₀ effects were also significant after controlling for multiple testing (family-wise error rate; FWER < 0.05). 5hmC was not correlated with personal measures of PM_2.5 and elemental components (FWER > 0.05). 5mC showed no correlations with PM₁₀, PM_2.5, and elemental components measures (FWER > 0.05). Our study suggests that exposure to ambient PM₁₀ affects 5hmC over time, but not 5mC. This finding demonstrates the need to differentiate 5hmC and 5mC in environmental studies of DNA methylation.     

Caspase proteolysis of the cohesin component RAD21 promotes apoptosis

Caspases are a conserved family of proteases that play a critical role in the execution of apoptosis by cleaving key cellular proteins at Asp residues and modifying their function. Using an expression cloning strategy we recently developed, we isolated human RAD21/SCC1/MCD1 as a novel caspase substrate. RAD21 is a component of the cohesin complex that holds sister chromatids together during mitosis and repairs double-strand DNA breaks. Interestingly, RAD21 is cleaved by a caspase-like Esp1/separase at the onset of anaphase to trigger sister chromatid separation. Here, we demonstrate that human RAD21 is preferentially cleaved at Asp(279) by caspases-3 and -7 in vitro to generate two major proteolytic products of approximately 65 and 48 kDa. Moreover, we show that RAD21 is specifically proteolyzed by caspases into a similarly sized 65-kDa carboxyl-terminal product in cells undergoing apoptosis in response to diverse stimuli. We also demonstrate that caspase proteolysis of RAD21 precedes apoptotic chromatin condensation and has important functional consequences, viz. the partial removal of RAD21 from chromatin and the production of a proapoptotic carboxyl-terminal cleavage product that amplifies the cell death signal. Taken together, these findings point to an entirely novel function of RAD21 in the execution of apoptosis.     

Development of a High-Throughput Fluorescence Polarization Assay to Identify Novel Ligands of Glutamate Carboxypeptidase II

Glutamate carboxypeptidase II (GCPII) is an important target for therapeutic and diagnostic interventions aimed at prostate cancer and neurologic disorders. Here we describe the development and optimization of a high-throughput screening (HTS) assay based on fluorescence polarization (FP) that facilitates the identification of novel scaffolds inhibiting GCPII. First, we designed and synthesized a fluorescence probe based on a urea-based inhibitory scaffold covalently linked to a Bodipy TMR fluorophore (TMRGlu). Next, we established and optimized conditions suitable for HTS and evaluated the assay robustness by testing the influence of a variety of physicochemical parameters (e.g., pH, temperature, time) and additives. Using known GCPII inhibitors, the FP assay was shown to be comparable to benchmark assays established in the field. Finally, we evaluated the FP assay by HTS of a 20 000-compound library. The novel assay presented here is robust, highly reproducible (Z' = 0.82), inexpensive, and suitable for automation, thus providing an excellent platform for HTS of small-molecule libraries targeting GCPII.     

Controlling plant growth via the gibberellin biosynthesis system – I. Growth parameter alterations in apple seedlings

'York Imperial' apple seedlings ( Malus domestica Borkh.) were continuously supplied via the roots with paclobutrazol [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol)], a triazole GA biosynthesis inhibitor, at 0.68 μ M in a nutrient solution. In comparison to controls, seedlings treated with paclobutrazol for 66 days showed a 91% reduction in shoot length, a 66% reduction in leaf area but only a 17% reduction in leaf number. This effect could be reversed by GA₃ applied to the foliage at 71.4 μ M 0, 19 or 35 days after paclobutrazol was initially supplied and leaf area values for paclobutrazol-treated seedlings given both treatments did not differ significantly from controls. Plots of growth data indicate linearity of shoot longitudinal growth of GA₃-treated seedlings. Leaf area increase was non-linear after GA₃ treatment up to approximately 30 days, when the rate dropped. On a per shoot basis, leaf weight closely followed leaf area but on a per unit area basis, paclobutrazol-treated leaves were heavier than controls; GA₃ applications temporarily reversed this trend.