Common genetic variants do not associate with CAD in familial hypercholesterolemia

In recent years, multiple loci dispersed on the genome have been shown to be associated with coronary artery disease (CAD). We investigated whether these common genetic variants also hold value for CAD prediction in a large cohort of patients with familial hypercholesterolemia (FH). We genotyped a total of 41 single-nucleotide polymorphisms (SNPs) in 1701 FH patients, of whom 482 patients (28.3%) had at least one coronary event during an average follow up of 66 years. The association of each SNP with event-free survival time was calculated with a Cox proportional hazard model. In the cardiovascular disease risk factor adjusted analysis, the most significant SNP was rs1122608:G>T in the SMARCA4 gene near the LDL-receptor (LDLR) gene, with a hazard ratio for CAD risk of 0.74 (95% CI 0.49–0.99; P-value 0.021). However, none of the SNPs reached the Bonferroni threshold. Of all the known CAD loci analyzed, the SMARCA4 locus near the LDLR had the strongest negative association with CAD in this high-risk FH cohort. The effect is contrary to what was expected. None of the other loci showed association with CAD.     

Genetic modifiers of EGFR dependence in non-small cell lung cancer

Lung adenocarcinomas harboring activating mutations in the epidermal growth factor receptor (EGFR) represent a common molecular subset of non-small cell lung cancer (NSCLC) cases. EGFR mutations predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs) and thus represent a dependency in NSCLCs harboring these alterations, but the genetic basis of EGFR dependence is not fully understood. Here, we applied an unbiased, ORF-based screen to identify genetic modifiers of EGFR dependence in EGFR-mutant NSCLC cells. This approach identified 18 kinase and kinase-related genes whose overexpression can substitute for EGFR in EGFR-dependent PC9 cells, and these genes include seven of nine Src family kinase genes, FGFR1, FGFR2, ITK, NTRK1, NTRK2, MOS, MST1R, and RAF1. A subset of these genes can complement loss of EGFR activity across multiple EGFR-dependent models. Unbiased gene-expression profiling of cells overexpressing EGFR bypass genes, together with targeted validation studies, reveals EGFR-independent activation of the MEK-ERK and phosphoinositide 3-kinase (PI3K)-AKT pathways. Combined inhibition of PI3K-mTOR and MEK restores EGFR dependence in cells expressing each of the 18 EGFR bypass genes. Together, these data uncover a broad spectrum of kinases capable of overcoming dependence on EGFR and underscore their convergence on the PI3K-AKT and MEK-ERK signaling axes in sustaining EGFR-independent survival.The term “oncogene addiction” has been used to describe the phenomenon whereby tumor cells exhibit singular reliance on an oncogene or oncogenic pathway for their survival, despite the accumulation of multiple genetic lesions (1). In non-small cell lung cancer (NSCLC), this principle is perhaps best exemplified with the finding that epidermal growth factor receptor (EGFR) mutations predict response to EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, and thus represent a dependency in the subset of tumors harboring these alterations (2–6). However, though EGFR-mutant NSCLCs typically respond dramatically to EGFR TKIs, clinical responses are not universal, even within this genetically defined cohort, with the rate of objective response estimated to be ∼71% (5, 6). Furthermore, the overwhelming majority of patients who initially respond to EGFR inhibitors ultimately develop resistance to therapy (7). A deeper understanding of the genetic underpinnings of EGFR addiction, and how EGFR-mutant cells can overcome reliance on EGFR, may improve clinical outcomes.Here, we have applied an unbiased screening approach to identify genetic modifiers of EGFR dependence in NSCLC. Mounting evidence supports the existence of several genetic modifiers of EGFR dependence in EGFR-mutant NSCLC, which can reduce the degree to which these tumors rely on EGFR and thereby contribute to EGFR TKI resistance (8). Examples include amplification of the MET receptor tyrosine kinase (RTK) (9), activation of the NF-κB pathway (8), amplification of the HER2 (ERBB2) RTK (10), amplification of the CRKL gene (11), and activation of the AXL kinase (12). Notably, MET bypass can be reciprocally achieved via EGFR activation in MET-dependent cells (13), and analogous examples of reciprocal kinase switching have been reported in other kinase-driven cancer models (14, 15). These and other findings suggest that compensatory kinase switching may be a more general way in which oncogene-dependent cancers overcome reliance on their primary driver kinase (14, 16), but the full-range of kinases capable of mediating EGFR bypass has not been systematically studied.Recent advances in large-scale functional genetic libraries have made it possible to query a wide range of genetic perturbations for their ability to modulate specific cellular phenotypes in mammalian systems (17, 18). Using the model of EGFR-mutant, erlotinib-sensitive NSCLC cells, we have performed a systematic ORF-based screen to identify kinase and kinase-related genes whose overexpression can complement loss of EGFR activity in an EGFR-dependent context. Our findings indicate broad potential for EGFR substitution in the setting of EGFR dependence, with compensatory mechanisms commonly conferring EGFR-independent activation of the PI3K-AKT and MEK-ERK signaling pathways. Importantly, this approach has recovered known mechanisms of erlotinib resistance as well as identified novel mediators of EGFR bypass in EGFR-mutant NSCLC. These data support the idea that the EGFR-dependent state can be redundantly driven by diverse genetic inputs that commonly converge on shared downstream signaling nodes.     

Why industrial methods do not work in healthcare: an analytical approach

Healthcare professionals and managers in hospitals are frequently suggested to learn from industry and business to improve quality and efficiency. However, evidence that the implementation of industrial techniques and business methods has a meaningful effect on patient outcomes is often lacking. An explanation for this phenomenon is thought to be the complexity of the hospital organisation and the diversity of patients. In this article, we use the practice approach to discuss the application of industrial techniques and business methods in healthcare. We employ a practice model that offers three perspectives to understand professional practices: Identity and intrinsic values, Interests of stakeholders, and Ideals and basic beliefs (Triple I). This model demonstrates that the nature of healthcare practices differs strongly from the nature of industrial and business practices. Healthcare has a moral nature that does not let itself be easily organised along technological or business categories. This may provide a fundamental explanation of why industrial techniques and business methods in general will be less successful in healthcare. At the same time, this model invites hospitals to develop innovative approaches that do justice to the identity and intrinsic values of healthcare. In this process, insights from industry and business cannot be copied but have to be used as sources of inspiration.     

Hepatic leptin signalling and subdiaphragmatic vagal efferents are not required for leptin-induced increases of plasma IGF binding protein-2 (IGFBP-2) in <Emphasis Type="Italic">ob/ob</Emphasis> mice

Aims/hypothesis  

The fat-derived hormone leptin plays a crucial role in the maintenance of normal body weight and energy expenditure as well as in glucose homeostasis. Recently, it was reported that the liver-derived protein, insulin-like growth factor binding protein-2 (IGFBP-2), is responsible for at least some of the glucose-normalising effects of leptin. However, the exact mechanism by which leptin upregulates IGFBP-2 production is unknown. Since it is believed that circulating IGFBP-2 is predominantly derived from the liver and leptin has been shown to have both direct and indirect actions on the liver, we hypothesised that leptin signalling in hepatocytes or via brain–liver vagal efferents may mediate leptin control of IGFBP-2 production.     

Diagnostic Value of Cytokines and Chemokines in Lyme Neuroborreliosis

The aims of the present study were to assess the concentrations of different cytokines and chemokines in blood serum and cerebrospinal fluid (CSF) samples of patients with Lyme neuroborreliosis and to identify the possible marker(s) that would enable a distinction between clinically evident and suspected Lyme neuroborreliosis, as well as between Lyme neuroborreliosis and tick-borne encephalitis (TBE). Our additional interest was to evaluate the relationship between cytokine and chemokine concentrations and Borrelia burgdorferi sensu lato isolation from CSF, as well as intrathecal synthesis of specific borrelial antibodies. We found that higher concentrations of CXCL13 and lower concentrations of interleukin 10 (IL-10) in serum were associated with higher odds for clinically evident Lyme neuroborreliosis compared to suspected Lyme neuroborreliosis, as well as to TBE. The concentrations of IL-2, IL-5, IL-6, IL-10, and CXCL13 in the CSF were higher in patients with evident Lyme neuroborreliosis than in those who were only suspected to have the disease. A comparison of CSF cytokine and chemokine levels in patients with and without intrathecal synthesis of specific borrelial antibodies revealed that CXCL13 CSF concentration is significantly associated with intrathecal synthesis of borrelial antibodies. A comparison of the cytokine and chemokine CSF concentrations in patients with clinically evident Lyme neuroborreliosis according to CSF culture results revealed that higher concentrations of gamma interferon (IFN-γ) were associated with lower odds of Borrelia isolation. Although several differences in the blood serum and CSF concentrations of various cytokines and chemokines between the groups were found, the distinctive power of the majority of these findings is low. Further research on well-defined groups of patients is needed to appraise the potential diagnostic usefulness of these concentrations.     

Transplant-associated and blood transfusion-associated tropical and parasitic infections

Blood transfusion and transplantation may represent efficient mechanisms of spreading infectious agents to naive populations. In the developed countries, as a consequence of globalization, several factors such as international commerce, tourism, and immigration have acted as important features for the emergence or reemergence of infectious diseases previously referred to as tropical. This article reviews the relevant bacterial, protozoan and viral infections that are more frequently associated with blood transfusion and/or solid organ or marrow transplantation and may affect susceptible populations worldwide.