We have deduced the entire 1,370-amino-acid sequence of the human insulin receptor precursor from a single complementary DNA clone. The precursor starts with a 27-amino-acid signal sequence, followed by the receptor alpha-subunit, a precursor processing enzyme cleavage site, then the beta-subunit containing a single 23-amino-acid transmembrane sequence. There are sequence homologies to human epidermal growth factor receptor and the members of the src family of oncogene products.

Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2.LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV-Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wntdriven cancers through the inhibition of PORCN.Wnt inhibition | β-catenin | HNSCC

Over the past 25 years, research in cancer therapeutics has largely focused on two distinct lines of enquiry. In one approach, efforts to understand the underlying cell-autonomous, genetic drivers of tumorigenesis have led to the development of clinically important targeted agents that result in profound, but often not durable, tumour responses in genetically defined patient populations. In the second parallel approach, exploration of the mechanisms of protective tumour immunity has provided several therapeutic strategies - most notably the 'immune checkpoint' antibodies that reverse the negative regulators of T cell function - that accomplish durable clinical responses in subsets of patients with various tumour types. The integration of these potentially complementary research fields provides new opportunities to improve cancer treatments. Targeted and immune-based therapies have already transformed the standard-of-care for several malignancies. However, additional insights into the effects of targeted therapies, along with conventional chemotherapy and radiation therapy, on the induction of antitumour immunity will help to advance the design of combination strategies that increase the rate of complete and durable clinical response in patients.

Chronic myeloid leukaemia (CML) is driven by the activity of the BCR-ABL1 fusion oncoprotein. ABL1 kinase inhibitors have improved the clinical outcomes for patients with CML, with over 80% of patients treated with imatinib surviving for more than 10 years. Second-generation ABL1 kinase inhibitors induce more potent molecular responses in both previously untreated and imatinib-resistant patients with CML. Studies in patients with chronic-phase CML have shown that around 50% of patients who achieve and maintain undetectable BCR-ABL1 transcript levels for at least 2 years remain disease-free after the withdrawal of treatment. Here we characterize ABL001 (asciminib), a potent and selective allosteric ABL1 inhibitor that is undergoing clinical development testing in patients with CML and Philadelphia chromosome-positive (Ph) acute lymphoblastic leukaemia. In contrast to catalytic-site ABL1 kinase inhibitors, ABL001 binds to the myristoyl pocket of ABL1 and induces the formation of an inactive kinase conformation. ABL001 and second-generation catalytic inhibitors have similar cellular potencies but distinct patterns of resistance mutations, with genetic barcoding studies revealing pre-existing clonal populations with no shared resistance between ABL001 and the catalytic inhibitor nilotinib. Consistent with this profile, acquired resistance was observed with single-agent therapy in mice; however, the combination of ABL001 and nilotinib led to complete disease control and eradicated CML xenograft tumours without recurrence after the cessation of treatment.

Preparations of insulin receptor from cultured 3T3-L1 adipocytes and human placenta previously was found to catalyze the phosphorylation of the 90,000-dalton component of the insulin receptor on tyrosine residues. This insulin-dependent phosphorylation has now been shown to coincide with the generation of an activated, insulin-independent, receptor protein kinase. Activation is dependent upon ATP, divalent cations (Mg2' and Mn2+), and insulin (half-maximal activation occurs at 6-8 nM insulin). The time required for activation is consistent with that needed for insulin-dependent self-phosphorylation of the receptor present in eluates from wheat germ lectin-agarose columns and in preparations of affinity-purified placental receptor. Activation proceeds unabated in the presence of soybean trypsin inhibitor at 0.1 mg/ml and the activated, insulin-independent, protein kinase sediments in 5-20% sucrose gradients at the same position as the unmodified receptor. Under steady-state conditions, the phosphorylated receptor binds insulin in the same fashion as the unmodified receptor. it is proposed that the self-phosphorylated form of the receptor is the insulin-activated protein kinase that catalyzes the phosphorylation of exogenous protein and peptide substrates. A corollary of this hypothesis is that enzymatic dephosphorylation may be essential for reversibly terminating the activity of the insulin-receptor protein Idnase.Insulin activates a protein kinase that catalyzes the phosphorylation of the insulin receptor in intact cells (1-3) and in preparations of purified insulin receptor (4). In vitro, the insulin receptor derived from cultured 3T3-L1 adipocytes and human placenta is phosphorylated on tyrosine residues in the 90,000-dalton subunit of the receptor (3, 5). Evidence that insulin-dependent tyrosine kinase activity copurifies with the receptor to near-homogeneity suggests that the receptor itself is the protein kinase. However, it is not known which of its subunits possesses this activity. All of the tyrdsine protein kinases that have been described thus far undergo self-phosphorylation. This modification, however, has not been reported to affect enzyme function.We have now found that incubation of the insulin receptor with insulin, ATP, and divalent cations under conditions in which it becomes phosphorylated stimulates its subsequent ability to catalyze the phosphorylation of exogenous substrates. The phosphorylated receptor remains fully active after gel filtration at pH 6.0, a procedure which restores insulin dependency to the insulin-treated, unphosphorylated receptor.MATERIALS AND METHODS Materials. To prepare insulin receptor, cultured 3T3-L1 adipocytes were grown and induced to differentiate as described (6). A glycoprotein-rich fraction derived from solubilized membranes of either human placenta or 3T3-L1 adipocytes was prepared by wheat germ agglutinin-agarose chromatography as described (3). This procedure purified the insulin receptor approximately 15-fold from the solubilized membranes and c...

The nuclear DNA-binding protein DEK is an autoantigen that has been implicated in the regulation of transcription, chromatin architecture, and mRNA processing. We demonstrate here that DEK is actively secreted by macrophages and is also found in synovial fluid samples from patients with juvenile arthritis. Secretion of DEK is modulated by casein kinase 2, stimulated by interleukin-8, and inhibited by dexamethasone and cyclosporine A, consistent with a role as a proinflammatory molecule. DEK is secreted in both a free form and in exosomes, vesicular structures in which transcription-modulating factors such as DEK have not previously been found. Furthermore, DEK functions as a chemotactic factor, attracting neutrophils, CD8؉ T lymphocytes, and natural killer cells. Therefore, the DEK autoantigen, previously described as a strictly nuclear protein, is secreted and can act as an extracellular chemoattractant, suggesting a direct role for DEK in inflammation.DEK is a mammalian oncoprotein and putative autoantigen whose primary biological function has not been previously elucidated, despite literature linking it to the regulation of transcription, chromatin architecture, and mRNA processing (1,2,11,15,16,24,35,51,65). The DEK protein is widely conserved among species and is transcribed at high levels, especially in hematopoietically derived cells (14,(62)(63)(64). DEK was first characterized as part of the protein product of the DEK-CAN fusion oncogene, resulting from a t(6;9) translocation found in a subset of patients with acute myelogenous leukemia (64). DEK is overexpressed in several different malignancies, including melanoma, hepatocellular carcinoma, glioblastoma, retinoblastoma, bladder cancer, T-cell large granular lymphocyte leukemia, and acute myelogenous leukemia independent of the t(6;9) translocation (7,10,19,20,29,30,32,39,64). Although DEK has previously been described as a strictly nuclear protein, DEK autoreactivity has been identified as a major component of the autoantibody profile in patients with juvenile idiopathic arthritis (JIA) and is also seen in patients with other autoimmune diseases (8,21,38,49,54,55). In the studies presented in this paper, we show that the nuclear protein DEK can be actively secreted by inflammatory cells, is found in synovial fluid samples from JIA patients, and can function as a chemoattractant for inflammatory cells, suggesting a potential role for DEK in immunity and/or autoimmunity. MATERIALS AND METHODSCell preparation. Monocyte-derived macrophages (MDM) were prepared as previously described (31). Briefly, heparinized venous blood samples were collected from healthy volunteers following a protocol approved by the institutional review board, and peripheral blood mononuclear cells were separated by FicollHypaque (Amersham Pharmacia Biotech AB, Uppsala, Sweden) density gradient centrifugation. MDM were purified by adherence to plastic for 2 h at 37°C at a concentration of 5 ϫ 10 5 /ml. Adherent cells were consistently Ͼ90% monocytes (31). Adherence-purified human mon...

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The chemokine IL-8 is found on the luminal side of vascular endothelial cells, where it is postulated to be immobilized during inflammation. In this study, we observed that immobilized IL-8 can stimulate neutrophils to firmly adhere to a substrate containing ICAM-1 in a static adhesion assay. Soluble IL-8 was then perfused over neutrophils rolling on P-selectin (P-sel) and ICAM-1, confirming that IL-8 in solution can quickly cause rolling neutrophils to arrest. To mimic a blood vessel wall with IL-8 expressed on the luminal surface of endothelial cells, IL-8 was immobilized along with P-sel and ICAM-1 at defined site densities to a surface. Neutrophils rolled an average of 200 μm on surfaces of P-sel, ICAM-1, and IL-8 before firmly adhering through ICAM-1-β2 integrin interactions at 2 dynes/cm2 wall shear stress. Increasing the density of IL-8 from 60 to 350 sites/μm2 on the surface decreased by 50% the average distance and time the neutrophils rolled before becoming firmly adherent. Temporal dynamics of ICAM-1-β2 integrin interactions of rolling neutrophils following IL-8 exposure suggest the existence of two classes of β2 integrin-ICAM-1 interactions, a low avidity interaction with a 65% increase in pause times as compared with P-sel-P-sel glycoprotein ligand-1 interactions, and a high avidity interaction with pause times 400% greater than the selectin interactions. Based on the proportionality between IL-8 site density and time to arrest, it appears that neutrophils may need to sample a critical number of IL-8 molecules presented by the vessel wall before forming a sufficient number of high avidity β2 integrin bonds for firm adhesion.