Structure and Dynamics of the EGF Receptor as Revealed by Experiments and Simulations and Its Relevance to Non-Small Cell Lung Cancer

The epidermal growth factor receptor (EGFR) is historically the prototypical receptor tyrosine kinase, being the first cloned and the first where the importance of ligand-induced dimer activation was ascertained. However, many years of structure determination has shown that EGFR is not completely understood. One challenge is that the many structure fragments stored at the PDB only provide a partial view because full-length proteins are flexible entities and dynamics play a key role in their functionality. Another challenge is the shortage of high-resolution data on functionally important higher-order complexes. Still, the interest in the structure/function relationships of EGFR remains unabated because of the crucial role played by oncogenic EGFR mutants in driving non-small cell lung cancer (NSCLC). Despite targeted therapies against EGFR setting a milestone in the treatment of this disease, ubiquitous drug resistance inevitably emerges after one year or so of treatment. The magnitude of the challenge has inspired novel strategies. Among these, the combination of multi-disciplinary experiments and molecular dynamic (MD) simulations have been pivotal in revealing the basic nature of EGFR monomers, dimers and multimers, and the structure-function relationships that underpin the mechanisms by which EGFR dysregulation contributes to the onset of NSCLC and resistance to treatment

Compositional Evolution of Individual CoNPs on Co/TiO2 during CO and Syngas Treatment Resolved through Soft XAS/X-PEEM

The nanoparticle (NP) redox state is an important parameter in the performance of cobalt-based Fischer-Tropsch synthesis (FTS) catalysts. Here, the compositional evolution of individual CoNPs (6-24 nm) in terms of the oxide vs metallic state was investigated in situ during CO/syngas treatment using spatially resolved X-ray absorption spectroscopy (XAS)/X-ray photoemission electron microscopy (X-PEEM). It was observed that in the presence of CO, smaller CoNPs (i.e., ≤12 nm in size) remained in the metallic state, whereas NPs ≥ 15 nm became partially oxidized, suggesting that the latter were more readily able to dissociate CO. In contrast, in the presence of syngas, the oxide content of NPs ≥ 15 nm reduced, while it increased in quantity in the smaller NPs; this reoxidation that occurs primarily at the surface proved to be temporary, reforming the reduced state during subsequent UHV annealing. O K-edge measurements revealed that a key parameter mitigating the redox behavior of the CoNPs were proximate oxygen vacancies (Ovac). These results demonstrate the differences in the reducibility and the reactivity of Co NP size on a Co/TiO2 catalyst and the effect Ovac have on these properties, therefore yielding a better understanding of the physicochemical properties of this popular choice of FTS catalysts

The Rho family GEF FARP2 is activated by aPKC iota to control tight junction formation and polarity

The elaboration of polarity is central to organismal development and to the maintenance of functional epithelia. Among the controls determining polarity are the PAR proteins, PAR6, aPKCι and PAR3, regulating both known and unknown effectors. Here, we identify FARP2 as a ‘RIPR’ motif-dependent partner and substrate of aPKCι that is required for efficient polarisation and junction formation. Binding is conferred by a FERM/FA domain–kinase domain interaction and detachment promoted by aPKCι-dependent phosphorylation. FARP2 is shown to promote GTP loading of Cdc42, which is consistent with it being involved in upstream regulation of the polarising PAR6–aPKCι complex. However, we show that aPKCι acts to promote the localised activity of FARP2 through phosphorylation. We conclude that this aPKCι−FARP2 complex formation acts as a positive feedback control to drive polarisation through aPKCι and other Cdc42 effectors

Drug-resistant EGFR mutations promote lung cancer by stabilizing interfaces in ligand-free kinase-active EGFR oligomers

The Epidermal Growth Factor Receptor (EGFR) is frequently found to be mutated in non-small cell lung cancer. Oncogenic EGFR has been successfully targeted by tyrosine kinase inhibitors, but acquired drug resistance eventually overcomes the efficacy of these treatments. Attempts to surmount this therapeutic challenge are hindered by a poor understanding of how and why cancer mutations specifically amplify ligand-independent EGFR auto-phosphorylation signals to enhance cell survival and how this amplification is related to ligand-dependent cell proliferation. Here we show that drug-resistant EGFR mutations manipulate the assembly of ligand-free, kinase-active oligomers to promote and stabilize the assembly of oligomer-obligate active dimer sub-units and circumvent the need for ligand binding. We reveal the structure and assembly mechanisms of these ligand-free, kinase-active oligomers, uncovering oncogenic functions for hitherto orphan transmembrane and kinase interfaces, and for the ectodomain tethered conformation of EGFR. Importantly, we find that the active dimer sub-units within ligand-free oligomers are the high affinity binding sites competent to bind physiological ligand concentrations and thus drive tumor growth, revealing a link with tumor proliferation. Our findings provide a framework for future drug discovery directed at tackling oncogenic EGFR mutations by disabling oligomer-assembling interactions

Cost of care for cancer patients in England: evidence from population-based patient-level data

background: Health systems are facing the challenge of providing care to an increasing population of patients with cancer. However, evidence on costs is limited due to the lack of large longitudinal databases. methods: We matched cost of care data to population-based, patient-level data on cancer patients in England. We conducted a retrospective cohort study including all patients age 18 and over with a diagnosis of colorectal (275 985 patients), breast (359 771), prostate (286 426) and lung cancer (283 940) in England between 2001 and 2010. Incidence costs, prevalence costs, and phase of care costs were estimated separately for patients age 18–64 and greater than or equal to65. Costs of care were compared by patients staging, before and after diagnosis, and with a comparison population without cancer. results: Incidence costs in the first year of diagnosis are noticeably higher in patients age 18–64 than age greater than or equal to65 across all examined cancers. A lower stage diagnosis is associated with larger cost savings for colorectal and breast cancer in both age groups. The additional costs of care because of the main four cancers amounts to £1.5 billion in 2010, namely 3.0% of the total cost of hospital care. conclusions: Population-based, patient-level data can be used to provide new evidence on the cost of cancer in England. Early diagnosis and cancer prevention have scope for achieving large cost savings for the health system

Building Babies - Chapter 16

In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

Genetic analysis of the vitamin D receptor gene in two epithelial cancers: melanoma and breast cancer case-control studies

<p>Abstract</p> <p>Background</p> <p>Vitamin D serum levels have been found to be related to sun exposure and diet, together with cell differentiation, growth control and consequently, cancer risk. Vitamin D receptor (<it>VDR</it>) genotypes may influence cancer risk; however, no epidemiological studies in sporadic breast cancer (BC) or malignant melanoma (MM) have been performed in a southern European population. In this study, the <it>VDR </it>gene has been evaluated in two epithelial cancers BC and MM.</p> <p>Methods</p> <p>We have conducted an analysis in 549 consecutive and non-related sporadic BC cases and 556 controls, all from the Spanish population, and 283 MM cases and 245 controls. Genotyping analyses were carried out on four putatively functional SNPs within the <it>VDR </it>gene.</p> <p>Results</p> <p>An association with the minor allele A of the non-synonymous SNP rs2228570 (rs10735810, <it>Fok</it>I, Met1Thr) was observed for BC, with an estimated odds ratio (OR) of 1.26 (95% CI = 1.02–1.57; p = 0.036). The synonymous variant rs731236 (<it>Taq</it>I) appeared to be associated with protection from BC (OR = 0.80, 95%CI = 0.64–0.99; p = 0.047). No statistically significant associations with MM were observed for any SNP. Nevertheless, sub-group analyses revealed an association between rs2228570 (<it>FokI</it>) and absence of childhood sunburns (OR = 0.65, p = 0.003), between the 3'utr SNP rs739837 (<it>Bgl</it>I) and fair skin (OR = 1.31, p = 0.048), and between the promoter SNP rs4516035 and the more aggressive tumour location in head-neck and trunk (OR = 1.54, p = 0.020).</p> <p>Conclusion</p> <p>In summary, we observed associations between SNPs in the <it>VDR </it>gene and BC risk, and a comprehensive analysis using clinical and tumour characteristics as outcome variables has revealed potential associations with MM. These associations required confirmation in independent studies.</p

Analysis of Aurora kinase A expression in CD34+ blast cells isolated from patients with myelodysplastic syndromes and acute myeloid leukemia

Aurora kinase A, also known as aurora A, is a serine/threonine kinase that plays critical roles in mitosis entry, chromosome alignment, segregation, and cytokinesis. Overexpression of aurora A has been observed in many solid tumors and some hematopoietic neoplasms, but little is known about its expression in myeloid diseases. Because cytogenetic abnormalities play an essential role in the pathogenesis of myeloid malignancies, we hypothesized that aurora A deregulation may be involved in myelodysplastic syndromes and acute myeloid leukemia and contribute to the chromosomal instability observed in these diseases. We assessed aurora A mRNA levels in CD34+ bone marrow blasts from nine patients with acute myeloid leukemia, 20 patients with myelodysplastic syndromes, and five normal patients serving as controls. CD34+ blasts were isolated from bone marrow aspirate specimens using magnetic activated cell separation technology. RNA was extracted from purified CD34+ cells, and quantitative real-time reverse transcriptase polymerase chain reaction for aurora A was performed. Immunocytochemical analyses for total aurora A, phosphorylated aurora A, Ki-67, and activated caspase 3 were performed on cytospin slides made from purified CD34+ cells in myelodysplastic syndrome patients using standard methods. Aurora A mRNA and protein levels were correlated, as was aurora A mRNA level, with blast counts, cytogenetic abnormalities, and International Prognostic Scoring System score. We found that CD34+ cells in myelodysplastic syndromes and acute myeloid leukemia expressed aurora A at significantly higher levels (P = 0.01 and P = 0.01, respectively) than normal CD34+ cells. Aurora A mRNA levels correlated with total and phosphorylated protein levels (P = 0.0002 and P = 0.02, respectively). No significant correlation was found between aurora A mRNA level and blast count, blast viability, cytogenetic abnormalities, or the International Prognostic Scoring System score in patients with myelodysplastic syndromes. We conclude that aurora A is up-regulated in CD34+ blasts from myeloid neoplasms

Cross-species amplification of 41 microsatellites in European cyprinids: A tool for evolutionary, population genetics and hybridization studies

<p>Abstract</p> <p>Background</p> <p>Cyprinids display the most abundant and widespread species among the European freshwater Teleostei and are known to hybridize quite commonly. Nevertheless, a limited number of markers for conducting comparative differentiation, evolutionary and hybridization dynamics studies are available to date.</p> <p>Findings</p> <p>Five multiplex PCR sets were optimized in order to assay 41 cyprinid-specific polymorphic microsatellite loci (including 10 novel loci isolated from <it>Chondrostoma nasus nasus, Chondrostoma toxostoma toxostoma </it>and <it>Leuciscus leuciscus</it>) for 503 individuals (440 purebred specimens and 63 hybrids) from 15 European cyprinid species. The level of genetic diversity was assessed in <it>Alburnus alburnus, Alburnoides bipunctatus, C. genei, C. n. nasus, C. soetta, C. t. toxostoma, L. idus, L. leuciscus, Pachychilon pictum, Rutilus rutilus, Squalius cephalus </it>and <it>Telestes souffia</it>. The applicability of the markers was also tested on <it>Abramis brama, Blicca bjoerkna </it>and <it>Scardinius erythrophtalmus </it>specimens. Overall, between 24 and 37 of these markers revealed polymorphic for the investigated species and 23 markers amplified for all the 15 European cyprinid species.</p> <p>Conclusions</p> <p>The developed set of markers demonstrated its performance in discriminating European cyprinid species. Furthermore, it allowed detecting and characterizing hybrid individuals. These microsatellites will therefore be useful to perform comparative evolutionary and population genetics studies dealing with European cyprinids, what is of particular interest in conservation issues and constitutes a tool of choice to conduct hybridization studies.</p