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241.
Johannessen CM Boehm JS Kim SY Thomas SR Wardwell L Johnson LA Emery CM Stransky N Cogdill AP Barretina J Caponigro G Hieronymus H Murray RR Salehi-Ashtiani K Hill DE Vidal M Zhao JJ Yang X Alkan O Kim S Harris JL Wilson CJ Myer VE Finan PM Root DE Roberts TM Golub T Flaherty KT Dummer R Weber BL Sellers WR Schlegel R Wargo JA Hahn WC Garraway LA 《Nature》2010,468(7326):968-972
Oncogenic mutations in the serine/threonine kinase B-RAF (also known as BRAF) are found in 50-70% of malignant melanomas. Pre-clinical studies have demonstrated that the B-RAF(V600E) mutation predicts a dependency on the mitogen-activated protein kinase (MAPK) signalling cascade in melanoma-an observation that has been validated by the success of RAF and MEK inhibitors in clinical trials. However, clinical responses to targeted anticancer therapeutics are frequently confounded by de novo or acquired resistance. Identification of resistance mechanisms in a manner that elucidates alternative 'druggable' targets may inform effective long-term treatment strategies. Here we expressed ~600 kinase and kinase-related open reading frames (ORFs) in parallel to interrogate resistance to a selective RAF kinase inhibitor. We identified MAP3K8 (the gene encoding COT/Tpl2) as a MAPK pathway agonist that drives resistance to RAF inhibition in B-RAF(V600E) cell lines. COT activates ERK primarily through MEK-dependent mechanisms that do not require RAF signalling. Moreover, COT expression is associated with de novo resistance in B-RAF(V600E) cultured cell lines and acquired resistance in melanoma cells and tissue obtained from relapsing patients following treatment with MEK or RAF inhibitors. We further identify combinatorial MAPK pathway inhibition or targeting of COT kinase activity as possible therapeutic strategies for reducing MAPK pathway activation in this setting. Together, these results provide new insights into resistance mechanisms involving the MAPK pathway and articulate an integrative approach through which high-throughput functional screens may inform the development of novel therapeutic strategies. 相似文献
242.
Bonnin A Goeden N Chen K Wilson ML King J Shih JC Blakely RD Deneris ES Levitt P 《Nature》2011,472(7343):347-350
Serotonin (5-hydroxytryptamine or 5-HT) is thought to regulate neurodevelopmental processes through maternal-fetal interactions that have long-term mental health implications. It is thought that beyond fetal 5-HT neurons there are significant maternal contributions to fetal 5-HT during pregnancy but this has not been tested empirically. To examine putative central and peripheral sources of embryonic brain 5-HT, we used Pet1(-/-) (also called Fev) mice in which most dorsal raphe neurons lack 5-HT. We detected previously unknown differences in accumulation of 5-HT between the forebrain and hindbrain during early and late fetal stages, through an exogenous source of 5-HT which is not of maternal origin. Using additional genetic strategies, a new technology for studying placental biology ex vivo and direct manipulation of placental neosynthesis, we investigated the nature of this exogenous source. We uncovered a placental 5-HT synthetic pathway from a maternal tryptophan precursor in both mice and humans. This study reveals a new, direct role for placental metabolic pathways in modulating fetal brain development and indicates that maternal-placental-fetal interactions could underlie the pronounced impact of 5-HT on long-lasting mental health outcomes. 相似文献
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L Goldman R J Rockwell D Richfield C Wilson M Franzen P O Smith S R Hyatt 《Nature》1969,221(5178):361-363
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Rick Wilson 《Systemic Practice and Action Research》2014,27(1):57-74
This article describes the work undertaken to apply the Vanguard Method (Seddon, Freedom from command and control: a better way to make the work work Vanguard Education Ltd., Buckingham, 2003) to a not-for-profit organisation that exists to provide support for adults with learning disabilities. As chief executive of the organisation, the author directly participated in the intervention. This article is therefore a personal reflection on the experience of a leader who has been a participant observer and has changed the way he thinks about the way services should be delivered. Along the way, the organisation uncovered and removed substantial waste whilst improving the way services were designed around the individual. 相似文献