Is the risk for secondary cancers after proton therapy enhanced distal to the Planning Target Volume? A two-case report with possible explanations

It is often assumed that radiation-induced secondary cancer after proton therapy forms preferentially close to the distal fall-off of the spread-out Bragg peak because of an increased relative biological effectiveness (RBE) with regard to cancer induction of low-energy protons. In this study we analyze to what extent dose gradients distal to the Planning Target Volume (PTV) may, independently from the RBE, contribute to enhanced radiation carcinogenesis. The study is based on two dogs which, out of 30 dogs treated with proton therapy at the Paul Scherrer Institute (PSI), developed a secondary cancer. Both dogs were originally diagnosed and treated for a fibrosarcoma and developed an osteosarcoma 48 and almost 60 months, respectively, after radiotherapy. From the dose distributions of the initial radiotherapy for both dogs three-dimensional maps of secondary cancer complication probability (SCCP) were computed. The SCCP maps were analyzed in the regions where the dogs developed a secondary cancer. The SCCP maps showed an enhanced risk in the regions of the femur where the secondary cancers were detected, as compared to the SCCP of the total femur. Excess risk of radiation-induced cancer at the distal part of proton radiation fields can thus be explained using SCCP calculations on the basis of the physical dose distributions. Therefore, the occurrence of secondary cancer close to the distal dose gradients of proton therapy is not necessarily due to an increased RBE of low-energy protons. More extensive studies based on more patients will be necessary to further elucidate the factors influencing the development of secondary tumors.     

Molecular cloning and characterization of the human S100A14 gene encoding a novel member of the S100 family

S100 proteins form a growing subfamily of proteins related by Ca2+-binding motifs to the Efhand Ca2+-binding protein superfamily. By analyzing a human lung cancer cell line subtraction cDNA library, we have identified and characterized a new member of the human S100 family that we named S100A14 (GenBank acc. no. NM_020672). It encodes a mRNA present in several normal human tissues of epithelial origin, with the highest level of expression in colon. The full-length cDNA is 1067 nt in length, with a coding region predicting a protein of 104 amino acids that is 68% homologous to the S100A13 protein. The deduced amino acid sequence of the human S100A14 and its mouse homolog (identified as GenBank entry) contains two EF-hand Ca2+-binding domains, a myristoylation motif, a glycosylation site, and several potential protein kinase phosphorylation sites. We have mapped this gene to human chromosome 1q21, within a region where at least 15 other S100 genes are tightly clustered. A 3.2-kb genomic fragment containing the entire S100A14 was cloned and sequenced. The gene is split into four exons and three introns spanning a total of 2165 bp of genomic sequence. We examined the intracellular distribution of the epitope-tagged S100A14 protein in two human lung carcinoma cell lines and one immortalized monkey cell line. Pronounced staining was observed in the cytoplasm, suggesting an association with the plasma membrane and in the perinuclear area. We also provide evidence for heterogenic expression of S100A14 in tumors, demonstrating its overexpression in ovary, breast, and uterus tumors and underexpression in kidney, rectum, and colon tumors, a pattern suggesting distinct regulation with potentially important functions in malignant transformation.     

"Personal best times in an olympic distance triathlon and a marathon predict an ironman race time for recreational female triathletes"

"The aim of this study was to investigate whether the characteristics of anthropometry, training or previous performance were related to an Ironman race time in recreational female Ironman triathletes. These characteristics were correlated to an Ironman race time for 53 recreational female triathletes in order to determine the predictor variables, and so be able to predict an Ironman race time for future novice triathletes. In the bi-variate analysis, no anthropometric characteristic was related to race time. The weekly cycling kilometers (r = -0.35) and hours (r = -0.32), as well as the personal best time in an Olympic distance triathlon (r = 0.49) and in a marathon (r = 0.74) were related to an Ironman race time (< 0.05). Stepwise multiple regressions showed that both the personal best time in an Olympic distance triathlon ( P = 0.0453) and in a marathon (P = 0.0030) were the best predictors for the Ironman race time (n = 28, r2 = 0.53). The race time in an Ironman triathlon might be partially predicted by the following equation (r2 = 0.53, n = 28): Race time (min) = 186.3 + 1.595 × (personal best time in an Olympic distance triathlon, min) + 1.318 × (personal best time in a marathon, min) for recreational female Ironman triathletes."     

Identification and Quantification of a New Family of Peptide Endocannabinoids (Pepcans) Showing Negative Allosteric Modulation at CB1 Receptors

The α-hemoglobin-derived dodecapeptide RVD-hemopressin (RVDPVNFKLLSH) has been proposed to be an endogenous agonist for the cannabinoid receptor type 1 (CB₁). To study this peptide, we have raised mAbs against its C-terminal part. Using an immunoaffinity mass spectrometry approach, a whole family of N-terminally extended peptides in addition to RVD-Hpα were identified in rodent brain extracts and human and mouse plasma. We designated these peptides Pepcan-12 (RVDPVNFKLLSH) to Pepcan-23 (SALSDLHAHKLRVDPVNFKLLSH), referring to peptide length. The most abundant Pepcans found in the brain were tested for CB₁ receptor binding. In the classical radioligand displacement assay, Pepcan-12 was the most efficacious ligand but only partially displaced both [³H]CP55,940 and [³H]WIN55,212-2. The data were fitted with the allosteric ternary complex model, revealing a cooperativity factor value α < 1, thus indicating a negative allosteric modulation. Dissociation kinetic studies of [³H]CP55,940 in the absence and presence of Pepcan-12 confirmed these results by showing increased dissociation rate constants induced by Pepcan-12. A fluorescently labeled Pepcan-12 analog was synthesized to investigate the binding to CB₁ receptors. Competition binding studies revealed K_i values of several Pepcans in the nanomolar range. Accordingly, using competitive ELISA, we found low nanomolar concentrations of Pepcans in human plasma and ∼100 pmol/g in mouse brain. Surprisingly, Pepcan-12 exhibited potent negative allosteric modulation of the orthosteric agonist-induced cAMP accumulation, [³⁵S]GTPγS binding, and CB₁ receptor internalization. Pepcans are the first endogenous allosteric modulators identified for CB₁ receptors. Given their abundance in the brain, Pepcans could play an important physiological role in modulating endocannabinoid signaling.     

Biological traits of European pond macroinvertebrates

Whilst biological traits of river macroinvertebrates show unimodal responses to geographic changes in habitat conditions in Europe, we still do not know whether spatial turnover of species result in distinct combinations of biological traits for pond macroinvertebrates. Here, we used data on the occurrence of 204 macroinvertebrate taxa in 120 ponds from four biogeographic regions of Europe, to compare their biological traits. The Mediterranean, Atlantic, Alpine, and Continental regions have specific climate, vegetation and geology. Only two taxa were exclusively found in the Alpine and Continental regions, while 28 and 34 taxa were exclusively recorded in the Atlantic and Mediterranean regions, respectively. Invertebrates in the Mediterranean region allocated much energy to reproduction and resistance forms. Most Mediterranean invertebrate species had narrow thermal ranges. In Continental areas, invertebrates allocated lesser energy to reproduction and dispersal, and organisms were short lived with high diversity of feeding groups. These characteristics suggest higher resilience. The main difference between ponds in the Alpine and Atlantic regions was their elevation. Alpine conditions necessitate specific adaptations related to rapid temperature fluctuations, and low nutrient concentrations. Even if our samples did not cover the full range of pond conditions across Europe, our analyses suggest that changes in community composition have important impacts on pond ecosystem functions. Consistent information on a larger set of ponds across Europe would be much needed, but their low accessibility (unpublished data and/or not disclosed by authors) remains problematic. There is still, therefore, a pressing need for the incorporation of high quality data sets into a standardized database so that they can be further analyzed in an integrated European-wide manner.     

Simultaneous acquisition of PAR and PAIN spectra

We present a scheme that allows the simultaneous detection of PAR and PAIN correlation spectra in a single two-dimensional experiment. For both spectra, we obtain almost the same signal-to-noise ratio as if a PAR or PAIN spectrum is recorded separately, which in turn implies that one of the spectra may be considered additional information for free. The experiment is based on the observation that in a PAIN experiment, the PAR condition is always also fulfilled. The performance is demonstrated experimentally using uniformly ¹³C,¹⁵N-labeled samples of N–f–MLF–OH and ubiquitin.     

Loss of secreted frizzled-related protein 4 correlates with an aggressive phenotype and predicts poor outcome in ovarian cancer patients

Background

Activation of the Wnt signaling pathway is implicated in aberrant cellular proliferation in various cancers. In 40% of endometrioid ovarian cancers, constitutive activation of the pathway is due to oncogenic mutations in β-catenin or other inactivating mutations in key negative regulators. Secreted frizzled-related protein 4 (SFRP4) has been proposed to have inhibitory activity through binding and sequestering Wnt ligands.

Methodology/Principal Findings

We performed RT-qPCR and Western-blotting in primary cultures and ovarian cell lines for SFRP4 and its key downstream regulators activated β-catenin, β-catenin and GSK3β. SFRP4 was then examined by immunohistochemistry in a cohort of 721 patients and due to its proposed secretory function, in plasma, presenting the first ELISA for SFRP4. SFRP4 was most highly expressed in tubal epithelium and decreased with malignant transformation, both on RNA and on protein level, where it was even more profound in the membrane fraction (p<0.0001). SFRP4 was expressed on the protein level in all histotypes of ovarian cancer but was decreased from borderline tumors to cancers and with loss of cellular differentiation. Loss of membrane expression was an independent predictor of poor survival in ovarian cancer patients (p = 0.02 unadjusted; p = 0.089 adjusted), which increased the risk of a patient to die from this disease by the factor 1.8.

Conclusions/Significance

Our results support a role for SFRP4 as a tumor suppressor gene in ovarian cancers via inhibition of the Wnt signaling pathway. This has not only predictive implications but could also facilitate a therapeutic role using epigenetic targets.     

Identification of immunogenic proteins of Waddlia chondrophila

Evidence is growing for a role of Waddlia chondrophila as an agent of adverse pregnancy outcomes in both humans and ruminants. This emerging pathogen, member of the order Chlamydiales, is also implicated in bronchiolitis and lower respiratory tract infections. Until now, the serological diagnosis of W. chondrophila infection has mainly relied on manually intensive tests including micro-immunofluorescence and Western blotting. Thus, there is an urgent need to establish reliable high throughput serological assays. Using a combined genomic and proteomic approach, we detected 57 immunogenic proteins of W. chondrophila, of which 17 were analysed by mass spectrometry. Two novel hypothetical proteins, Wim3 and Wim4, were expressed as recombinant proteins in Escherichia coli, purified and used as antigens in an ELISA test. Both proteins were recognized by sera of rabbits immunized with W. chondrophila as well as by human W. chondrophila positive sera but not by rabbit pre-immune sera nor human W. chondrophila negative sera. These results demonstrated that the approach chosen is suitable to identify immunogenic proteins that can be used to develop a serological test. This latter will be a valuable tool to further clarify the pathogenic potential of W. chondrophila.     

Chromatin as an expansive canvas for chemical biology

Chromatin is extensively chemically modified and thereby acts as a dynamic signaling platform controlling gene function. Chromatin regulation is integral to cell differentiation, lineage commitment and organism development, whereas chromatin dysregulation can lead to age-related and neurodegenerative disorders as well as cancer. Investigating chromatin biology presents a unique challenge, as the issue spans many disciplines, including cell and systems biology, biochemistry and molecular biophysics. In recent years, the application of chemical biology methods for investigating chromatin processes has gained considerable traction. Indeed, chemical biologists now have at their disposal powerful chemical tools that allow chromatin biology to be scrutinized at the level of the cell all the way down to the single chromatin fiber. Here we present recent examples of how this rapidly expanding palette of chemical tools is being used to paint a detailed picture of chromatin function in organism development and disease.