Castration-resistant prostate cancer (CRPC) remains a major clinical challenge because of the lack of effective targeted therapy for its treatment. The mechanism underlying how CRPC gains resistance ...toward hormone depletion and other forms of chemotherapy is poorly understood. Research on understanding the factors that drive these processes is desperately needed to generate new therapies to cure the disease. Here, we discovered a fundamental role of S-phase protein kinase 2 (Skp2) in the formation and progression of CRPC. In transgenic adenocarcinoma mouse prostate model, Skp2 depletion leads to a profound repression of prostate tumor growth and distal metastasis and substantially prolonged overall survival. We revealed that Skp2 regulates CRPC through Twist-mediated oncogenic functions including epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) acquisitions. Mechanistically, Skp2 interacted with Twist and promoted the non-degradative ubiquitination of Twist. Consequently, Skp2 stabilized Twist protein expression by preventing proteasomal degradation of Twist by β-TrCP. We found that Twist overexpression augments CSC self-renewal and population and that Skp2 inhibition reverts Twist's effects on CSC regulation. Furthermore, genetically depleting or pharmacologically inactivating Skp2 synergistically re-sensitized CRPC cells toward chemotherapies such as paclitaxel or doxorubicin. Together, this study uncovering Skp2-mediated Twist stabilization and oncogenic functions in CRPC offers new knowledge on how CRPC progresses and acquires chemoresistance during tumor progression. It provides proof of principle that Skp2 targeting is a promising approach to combat metastatic CRPC by targeting Twist and CSCs.
Surface mechanical attrition treatment (SMAT), an efficient way to create nanostructured surface/subsurface layers, has been extensively exploited in the last decade. However, the impact velocity of ...the balls in the treatment has not yet been measured in detail. The motivation of the present paper was to investigate the ball velocity and the effect of the number of balls on the resulting mechanical properties and the associated microstructures. Employing a high-speed camera, the maximum impact velocities of balls were quantified. This velocity is affected by the density and size of the ball. In the present paper an optimum number of balls for SMAT was also identified. With a detailed knowledge of the ball velocity we were able to accurately estimate the strain rate at different depths by analytical modeling and to study the correlation between the resulting microstructures and the strain/strain rate history of the material.
As the most common subtype of Leber congenital amaurosis (LCA), LCA10 is a severe retinal dystrophy caused by mutations in the CEP290 gene. The most frequent mutation found in patients with LCA10 is ...a deep intronic mutation in CEP290 that generates a cryptic splice donor site. The large size of the CEP290 gene prevents its use in adeno-associated virus (AAV)-mediated gene augmentation therapy. Here, we show that targeted genomic deletion using the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system represents a promising therapeutic approach for the treatment of patients with LCA10 bearing the CEP290 splice mutation. We generated a cellular model of LCA10 by introducing the CEP290 splice mutation into 293FT cells and we showed that guide RNA pairs coupled with SpCas9 were highly efficient at removing the intronic splice mutation and restoring the expression of wild-type CEP290. In addition, we demonstrated that a dual AAV system could effectively delete an intronic fragment of the Cep290 gene in the mouse retina. To minimize the immune response to prolonged expression of SpCas9, we developed a self-limiting CRISPR/Cas9 system that minimizes the duration of SpCas9 expression. These results support further studies to determine the therapeutic potential of CRISPR/Cas9-based strategies for the treatment of patients with LCA10.
LCA10 is caused by mutations in CEP290, which is too large for the gene therapy vector AAV. Here, Ruan et al. show that gene editing using CRISPR/Cas9 represents a promising therapeutic approach to treat LCA10. They also develop a self-limiting CRISPR/Cas9 system to limit duration of Cas9 expression.
In the top-down approach to tailor the microstructures of materials via plastic deformation, the strain rate plays a significant role. This paper systematically investigates the deformation ...mechanisms of 304 stainless steel subjected to surface impacts over a wide range of strain rates (10–10
5
s
−1). Based on comprehensive analysis of X-ray diffraction and electron microscopy observations, we found that the strain rate between 10 and 10
3
s
−1 only activated dislocation motions and α′-martensite transformations, resulting in nanocrystallines and ultra-fine grains. However, higher strain rates (10
4–10
5
s
−1) produced a high density of twin bundles with nanoscale thickness in the bulk material. The transition from dislocation-mediated mechanism to twinning-mediated mechanism was interpreted in terms of the magnitude of the applied stress, which was calculated from the explicit finite-element simulation with the use of the Johnson–Cook model. A critical twinning stress, determined from the infinite separation of Shockley partials, renders the transition point. Deformation twinning occurs when the applied stress exceeds this critical twinning stress. Larger stress leads to thinner and denser twin lamellae. Conversely, the stress below the transition point can only induce dislocation motions and α′-martensite transformations.
Summary
Background
Thiopurine‐induced leukopenia is the most common dangerous adverse event in Asians. NUDT15 R139C was recently proposed to be a promising biomarker for leukopenia with thiopurine ...therapy in Asians, but this has not been replicated in the Chinese population.
Aim
To investigate the influence of NUDT15 R139C, thiopurine S‐methyltransferase (TPMT), 6‐TGN and 6‐MMPR on thiopurine‐induced leukopenia in Chinese patients with Crohn's disease.
Methods
Clinical and epidemiological characteristics were reviewed from medical records. NUDT15 R139C and TPMT were genotyped. 6‐TGN/6‐MMPR concentrations were measured with high‐performance liquid chromatography (HPLC).
Results
A total of 253 patients were included, 65 (25.7%) of whom experienced leukopenia. The median follow‐up with thiopurine treatment was 38.0 weeks (range, 1–192 weeks). NUDT15 R139C was strongly associated with the incidence of leukopenia (70.2% mutation vs. 12.8% wild type; P=8.61×10−19; odds ratio, 10.80; 95% CI, 5.89–19.83). However, TPMT genotype was not found to be correlated with the incidence of leukopenia (P = 0.44). In subgroup of NUDT15 wild type, there was significant difference of 6TGN concentration between patients with and without leukopenia (413.0 (174.2–831.4) vs. 279.7 (77.3–666.9) pmol/8 × 108 RBC, P = 0.0055). In contrast, no association was found in patients with NUDT15 R139C variant alleles (P = 0.26). 6‐MMPR was not correlated with leukopenia (P = 0.84).
Conclusions
In Chinese patients, it is strongly recommended to detect NUDT15 genotype rather than TPMT before initiating thiopurine drugs. 6TGN concentration should be routinely monitored in CD patients with NUDT15 wild type. As for CT genotype, starting at low dose and careful monitoring for leukopenia and 6TGN levels is recommended.
Background and purpose
The present study aimed to examine how long‐term migration to high‐altitude regions affects mentality and cognition, and the correlation with various physiological and ...biochemical changes.
Methods
The WHO Neurobehavioral Core Test Battery, Raven's Standard Progressive Matrices (RSPM) and Pittsburgh Sleep Quality Index questionnaire were used to assess 141 young male subjects who lived in plain regions and 217 young male subjects who had migrated to a 4500 m high‐altitude region and lived there for 1–5 years. Arterial oxyhemoglobin saturation, cerebral tissue oxygenation indices (TOIs), serum S100B and brain‐derived neurotrophic factor (BDNF) were also measured.
Results
Long‐term migrators to a high‐altitude region exhibited exacerbated mood disorders, retarded color discrimination ability, decreased visual memory capacity, and impaired perceptual motor skill and motion stability. In addition, the migrators exhibited lower RSPM scores and lower sleep quality. Further analyses revealed significant correlations between sleep quality and cerebral TOIs, mood and sleep quality, mood and certain cognitive functions, mood and serum BDNF levels, and RSPM scores and serum S100B levels.
Conclusions
Long‐term living at high altitudes causes significant impairment of psychological and cognitive function. Cerebral hypoxic extent, sleep quality and biochemical dysfunction are major influencing factors.
Soil microbes comprise a large portion of the genetic diversity on Earth and influence a large number of important ecosystem processes. Increasing atmospheric nitrogen (N) deposition represents a ...major global change driver; however, it is still debated whether the impacts of N deposition on soil microbial biomass and respiration are ecosystem-type dependent. Moreover, the extent of N deposition impacts on microbial composition remains unclear. Here we conduct a global meta-analysis using 1408 paired observations from 151 studies to evaluate the responses of soil microbial biomass, composition, and function to N addition. We show that nitrogen addition reduced total microbial biomass, bacterial biomass, fungal biomass, biomass carbon, and microbial respiration. Importantly, these negative effects increased with N application rate and experimental duration. Nitrogen addition reduced the fungi to bacteria ratio and the relative abundances of arbuscular mycorrhizal fungi and gram-negative bacteria and increased gram-positive bacteria. Our structural equation modeling showed that the negative effects of N application on soil microbial abundance and composition led to reduced microbial respiration. The effects of N addition were consistent across global terrestrial ecosystems. Our results suggest that atmospheric N deposition negatively affects soil microbial growth, composition, and function across all terrestrial ecosystems, with more pronounced effects with increasing N deposition rate and duration.
Osteoarthritis (OA) is a common degenerative condition that afflicts more than 70% of the population between 55 and 77 years of age. Although its prevalence is rising globally with aging of the ...population, current therapy is limited to symptomatic relief and, in severe cases, joint replacement surgery. We report that intra-articular expression of proteoglycan 4 (Prg4) in mice protects against development of OA. Long-term Prg4 expression under the type II collagen promoter (Col2a1) does not adversely affect skeletal development but protects from developing signs of age-related OA. The protective effect is also shown in a model of posttraumatic OA created by cruciate ligament transection. Moreover, intra-articular injection of helper-dependent adenoviral vector expressing Prg4 protected against the development of posttraumatic OA when administered either before or after injury. Gene expression profiling of mouse articular cartilage and in vitro cell studies show that Prg4 expression inhibits the transcriptional programs that promote cartilage catabolism and hypertrophy through the up-regulation of hypoxia-inducible factor 3α. Analyses of available human OA data sets are consistent with the predictions of this model. Hence, our data provide insight into the mechanisms for OA development and offer a potential chondroprotective approach to its treatment.
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