Chk1 and 14-3-3 proteins inhibit atypical E2Fs to prevent a permanent cell cycle arrest

The atypical E2Fs, E2F7 and E2F8, act as potent transcriptional repressors of DNA replication genes providing them with the ability to induce a permanent S-phase arrest and suppress tumorigenesis. Surprisingly in human cancer, transcript levels of atypical E2Fs are frequently elevated in proliferating cancer cells, suggesting that the tumor suppressor functions of atypical E2Fs might be inhibited through unknown post-translational mechanisms. Here, we show that atypical E2Fs can be directly phosphorylated by checkpoint kinase 1 (Chk1) to prevent a permanent cell cycle arrest. We found that 14-3-3 protein isoforms interact with both E2Fs in a Chk1-dependent manner. Strikingly, Chk1 phosphorylation and 14-3-3-binding did not relocate or degrade atypical E2Fs, but instead, 14-3-3 is recruited to E2F7/8 target gene promoters to possibly interfere with transcription. We observed that high levels of 14-3-3 strongly correlate with upregulated transcription of atypical E2F target genes in human cancer. Thus, we reveal that Chk1 and 14-3-3 proteins cooperate to inactivate the transcriptional repressor functions of atypical E2Fs. This mechanism might be of particular importance to cancer cells, since they are exposed frequently to DNA-damaging therapeutic reagents

HPV-Related Nonkeratinizing Squamous Cell Carcinoma of the Oropharynx: Utility of Microscopic Features in Predicting Patient Outcome

Human papilloma virus (HPV) is an etiologic agent in a subset of oropharyngeal squamous cell carcinomas (SCCs). The aim of this study was to sub-classify SCC of the oropharynx based upon histologic features into nonkeratinizing (NK) SCC, keratinizing (K) SCC, and hybrid SCC, and determine the frequency of HPV and patient survival in each group. Patients with oropharyngeal SCC with a minimum of 2 years of clinical follow-up were identified from radiation oncology databases from 1997 to 2004. All patients received either up front surgery with postoperative radiation or definitive radiation based therapy. In situ hybridization (ISH) for high-risk HPV subtypes and immunohistochemistry for p16, a protein frequently up-regulated in HPV-associated carcinomas, were performed. Overall and disease-specific survival were assessed. Of 118 cases, 46.6% were NK SCC, 24.6% K SCC and 28.8% hybrid SCC. NK SCC occurred in slightly younger patients that were more often male. It more frequently presented with lymph node metastases and was surgically resected compared to K SCC. NK SCC was significantly more likely to be HPV and p16 positive than KSCC (P < 0.001) and to have better overall and disease-specific survival (P = 0.0002; P = 0.0142, respectively). Hybrid SCC was also more likely than K SCC to be HPV and p16 positive (P = 0.003; P = 0.002, respectively) and to have better overall survival (P = 0.0105). Sub-classification of oropharyngeal SCC by histologic type provides useful clinical information. NK SCC histology strongly predicts HPV-association and better patient survival compared to K SCC. Hybrid SCC appears to have an intermediate frequency of HPV-association and patient survival

Isolated Hypoxic Hepatic Perfusion with Retrograde Outflow in Patients with Irresectable Liver Metastases; A New Simplified Technique in Isolated Hepatic Perfusion

Background: Isolated hepatic perfusion with high-dose chemotherapy is a treatment option for patients with irresectable metastases confined to the liver. Prolonged local control and impact on survival have been claimed. Major drawbacks are magnitude and costs of the procedure. We developed an isolated hypoxic h

The impact of childhood abuse and recent stress on serum brain-derived neurotrophic factor and the moderating role of BDNF Val66Met

Contains fulltext : 98431.pdf (publisher's version ) (Open Access)RATIONALE: Recent findings show lowered brain-derived neurotrophic factor (BDNF) levels in major depressive disorder (MDD). Exposure to stressful life events may (partly) underlie these BDNF reductions, but little is known about the effects of early or recent life stress on BDNF levels. Moreover, the effects of stressful events on BDNF levels may in part be conditional upon a common variant on the BDNF gene (Val(66)Met; RS6265), with the Met allele being associated with a decrease in activity-dependent secretion of BDNF compared to the Val allele. METHODS: We investigated cross-sectionally in 1,435 individuals with lifetime MDD the impact of childhood abuse (CA) and recent life events on serum BDNF levels and assessed whether the impact of these events was moderated by the BDNF Val(66)Met polymorphism. RESULTS: Overall, BDNF Met carriers had reduced serum BDNF levels when exposed to CA in a dose-dependent way. Moreover, exposure to recent life events was also associated with decreases in BDNF levels, but this was independent of BDNF Val(66)Met. Moreover, when not exposed to CA, Met carriers had higher BDNF levels than the Val/Val individuals, who did not show decreases in BDNF associated with CA. Finally, these findings were only apparent in the MDD group without comorbid anxiety. CONCLUSIONS: These gene-environment interactions on serum BDNF levels suggest that Met carriers are particularly sensitive to (early) stressful life events, which extends previous findings on the moderating role of the BDNF Val(66)Met polymorphism in the face of stressful life events

Genomic profiling identifies common HPV-associated chromosomal alterations in squamous cell carcinomas of cervix and head and neck

<p>Abstract</p> <p>Background</p> <p>It is well known that a persistent infection with high-risk human papillomavirus (hrHPV) is causally involved in the development of squamous cell carcinomas of the uterine cervix (CxSCCs) and a subset of SCCs of the head and neck (HNSCCs). The latter differ from hrHPV-negative HNSCCs at the clinical and molecular level.</p> <p>Methods</p> <p>To determine whether hrHPV-associated SCCs arising from different organs have specific chromosomal alterations in common, we compared genome-wide chromosomal profiles of 10 CxSCCs (all hrHPV-positive) with 12 hrHPV-positive HNSCCs and 30 hrHPV-negative HNSCCs. Potential organ-specific alterations and alterations shared by SCCs in general were investigated as well.</p> <p>Results</p> <p>Unsupervised hierarchical clustering resulted in one mainly hrHPV-positive and one mainly hrHPV-negative cluster. Interestingly, loss at 13q and gain at 20q were frequent in HPV-positive carcinomas of both origins, but uncommon in hrHPV-negative HNSCCs, indicating that these alterations are associated with hrHPV-mediated carcinogenesis. Within the group of hrHPV-positive carcinomas, HNSCCs more frequently showed gains of multiple regions at 8q whereas CxSCCs more often showed loss at 17p. Finally, gains at 3q24-29 and losses at 11q22.3-25 were frequent (>50%) in all sample groups.</p> <p>Conclusion</p> <p>In this study hrHPV-specific, organ-specific, and pan-SCC chromosomal alterations were identified. The existence of hrHPV-specific alterations in SCCs of different anatomical origin, suggests that these alterations are crucial for hrHPV-mediated carcinogenesis.</p

The longitudinal assessment of osteomyelitis development by mlecular imaging in a rabbit model

\u3cp\u3eIntroduction. Osteomyelitis is a severe orthopaedic complication which is difficult to diagnose and treat. Previous experimental studies mainly focussed on evaluating osteomyelitis in the presence of an implant or used a sclerosing agent to promote infection onset. In contrast, we focused on the longitudinal assessment of a nonimplant related osteomyelitis. Methods. An intramedullary tibial infection with S. aureus was established in NZW rabbits. Clinical and haematological infection status was evaluated weekly, combined with X-ray radiographs, biweekly injections of calcium binding fluorophores, and postmortem micro-CT. The development of the infection was assessed by micro-PET at consecutive time points using \u3csup\u3e18\u3c/sup\u3eF-FDG as an infection tracer. Results. The intramedullary contamination of the rabbit tibia resulted in an osteomyelitis. Haematological parameters confirmed infection in mainly the first postoperative weeks (CRP at the first 5 postoperative weeks, leucocyte differentiation at the second and sixth postoperative weeks, and ESR on the second postoperative week only), while micro-PET was able to detect the infection from the first post-operative week onward until the end of the study. Conclusions. This study shows that osteomyelitis in the rabbit can be induced without use of an implant or sclerosing agent. The sequential follow-up indicates that the diagnostic value of each infection parameter is time point dependant. Furthermore, from all parameters used, the diagnostic value of \u3csup\u3e18\u3c/sup\u3eF-FDG micro-PET is the most versatile to assess the presence of an orthopaedic infection in this model.\u3c/p\u3

Evaluation of a short dynamic F-18-fluoride PET/CT scanning method to assess bone metabolic activity in spinal orthopedics

A complication after spinal fusion surgery is pseudarthrosis, but its radiological diagnosis is of limited value. F-18-fluoride PET with its ability to assess bone metabolism activity could be of value. The goal of this study was to assess the clinical feasibility of calculating the static standardized uptake value (SUV) from a short dynamic scan without the use of blood sampling, thereby obtaining all dynamic and static parameters in a scan of only 30 min. This approach was tested on a retrospective patient population with persisting pain after spinal fusion surgery. In 16 patients, SUVs (SUVmax, SUVmean) and kinetic parameters (K (1), k (2), k (3), v (b), K (i,NLR), K (1)/k (2), k (3)/(k (2) + k (3)), K (i,patlak)) were derived from static and dynamic PET/CT scans of operated and control regions of the spine, after intravenous administration of 156-214 MBq F-18-fluoride. Parameter differences between control and operated regions, as well as between pseudarthrosis and fused segments were evaluated. SUVmean at 30 and 60 min was calculated from kinetic parameters obtained from the dynamic data set (SUVmean,2TCM). Agreement between measured and calculated SUVs was evaluated through Bland-Altman plots. Overall, statistically significant differences between control and operated regions were observed for SUVmax, SUVmean, K (i,NLR), K (i,patlak), K (1)/k (2) and k (3)/(k (2) + k (3)). Diagnostic CT showed pseudarthrosis in 6/16 patients, while in 10/16 patients, segments were fused. Of all parameters, only those regarding the incorporation of bone [K (i,NLR), K (i,patlak), k (3)/(k (2) + k (3))] differed statistically significant in the intervertebral disc space between the pseudarthrosis and fused patients group. The mean values of the patient-specific blood clearance rate differed statistically significant between the pseudarthrosis and the fusion group, with a p value of 0.011. This may correspond with the lack of statistical significance of the SUV values between pseudarthrosis and fused patients. Bland-Altman plots show that calculated SUVmean,2TCM values corresponded well with the measured SUVmean values. This study shows the feasibility of a 30-min dynamic F-18-fluoride PET/CT scanning and this may provide dynamic parameters clinically relevant to the diagnosis of pseudarthrosis