siRNA targeting the IRF2 transcription factor inhibits leukaemic cell growth.

Interferon regulatory factor (IRF) 1 and its functional antagonist IRF2 were originally discovered as transcription factors that regulate the interferon-beta gene. Control of cell growth has led to the definition of IRF1 as a tumour suppressor gene and IRF2 as an oncogene. Clinically, approximately 70% of cases of acute myeloid leukaemia demonstrate dysregulated expression of IRF1 and/or IRF2.

Extracellular matrix regulation of autophagy.

Integrin-mediated attachment of epithelial cells to extracellular matrix (ECM) is crucial for proper growth and survival. Although detachment leads to apoptosis, termed anoikis, recent work demonstrates that ECM detachment also robustly induces autophagy, a tightly regulated lysosomal self-digestion process that actually promotes survival. Autophagy presumably protects epithelial cells from the stresses of ECM detachment, allowing them to survive provided that they reattach in a timely manner.

Molecular recollision interferometry in high harmonic generation.

We use extreme-ultraviolet interferometry to measure the phase of high-order harmonic generation from transiently aligned CO(2) molecules. We unambiguously observe a reversal in phase of the high-order harmonic emission for higher harmonic orders with a sufficient degree of alignment. This results from molecular-scale quantum interferences between the molecular electronic wave function and the recolliding electron as it recombines with the molecule, and is consistent with a two-center model.

Cell-division inhibitors: new insights for future antibiotics.

The growing problem of antibiotic resistance has been exacerbated by the use of new drugs that are merely variants of older overused antibiotics. While it is naive to expect to restrain the spread of resistance without controlling antibacterial usage, the desperate need for drugs with novel targets has been recognized by health organizations, industry and academia alike. The wealth of knowledge available about the bacterial cell-division pathway has aided target-driven approaches to identify novel inhibitors.

Initial testing (stage 1) of sunitinib by the pediatric preclinical testing program.

Background: Sunitinib is an orally bioavailable, multi-targeted tyrosine kinase inhibitor with selectivity for PDGF receptors, VEGF receptors, FLT3, and KIT.

Procedures: Sunitinib was tested at concentrations ranging from 0.1 nM to 1.

Stage 1 testing and pharmacodynamic evaluation of the HSP90 inhibitor alvespimycin (17-DMAG, KOS-1022) by the pediatric preclinical testing program.

Background: Alvespimycin (17-DMAG, KOS-1022), a potent small-molecule inhibitor of the protein chaperone Hsp90, is being developed as an anticancer agent because of the multiple Hsp90 client proteins involved in cancer cell growth and survival.

Procedures: Alvespimycin was tested against the in vitro panel of the Pediatric Preclinical Testing Program (PPTP) at concentrations from 1 nM to 10 microM and was tested against the PPTP's in vivo tumor panels by intraperitoneal administration using a 50 mg/kg BID twice weekly x 6 weeks dose and schedule. Hsp70 induction in tumor and liver tissue was used as a pharmacodynamic measure of Hsp90 inhibition and stress response induction.

Initial testing (stage 1) of a monoclonal antibody (SCH 717454) against the IGF-1 receptor by the pediatric preclinical testing program.

Background: SCH 717454 (19D12) is a fully human antibody directed against the insulin-like growth factor 1 receptor (IGF-1R), which is implicated in the growth and metastatic phenotype of a broad range of malignancies. The activity of SCH 717454 was evaluated against the in vitro and in vivo panels of the Pediatric Preclinical Testing Program (PPTP).

Procedures: SCH 717454 was tested against the PPTP in vitro panel at concentrations ranging from 0.

Proteomic analysis of the venom of Heterometrus longimanus (Asian black scorpion).

Venoms have evolved over millions of years into potent cocktails of bioactive peptides and proteins. These compounds can be of great value to the pharmaceutical industry for numerous clinical applications. In this study, a novel proteomic - bioinformatic approach was utilised, where chromatography followed by gel electrophoresis was utilised to separate the venom peptides/proteins of Heterometrus longimanus (Asian black scorpion).

Pitfalls in the performance and interpretation of clinical immunology tests.

A broad overview, with examples, of the potential pitfalls encountered in the clinical immunology laboratory is presented. Illustrative examples and case scenarios are provided from autoimmunity, immunochemistry and cellular immunology, looking at both technical and interpretative pitfalls.

Emerging therapies for respiratory diseases.

This Society for Medicines Research symposium, sponsored by UCB, was held on September 11, 2007, at the Wellcome Trust Conference Centre, Hinxton, Cambridge, United Kingdom. The meeting, organized by Ruth Lock, Steve Collingwood and Andrew Ratcliffe, reviewed current thinking in the area of airway drug delivery and the challenges and progress made in the discovery and development of novel medicines to treat respiratory diseases, such as chronic obstructive pulmonary disease, asthma, allergic rhinitis and cystic fibrosis.

Insight into the selectivity of arsenic trioxide for acute promyelocytic leukemia cells by characterizing Saccharomyces cerevisiae deletion strains that are sensitive or resistant to the metalloid.

The genome-wide set of Saccharomyces cerevisiae deletion strains provides the opportunity to analyze how other organisms may respond to toxic agents. Since arsenic trioxide selectively kills human acute promyelocytic leukemia (APL) cells by a poorly understood mechanism we screened the yeast deletion strains for sensitivity or resistance. In addition to confirming mutants previously identified as sensitive to sodium arsenite, a large number of additional genes, and cellular processes, were required for arsenic trioxide tolerance.

Induction of autophagy during extracellular matrix detachment promotes cell survival.

Autophagy has been proposed to promote cell death during lumen formation in three-dimensional mammary epithelial acini because numerous autophagic vacuoles are observed in the dying central cells during morphogenesis. Because these central cells die due to extracellular matrix (ECM) deprivation (anoikis), we have directly interrogated how matrix detachment regulates autophagy. Detachment induces autophagy in both nontumorigenic epithelial lines and in primary epithelial cells.

Initial testing (stage 1) of the BH3 mimetic ABT-263 by the pediatric preclinical testing program.

Background: ABT-263 is a potent (K(i) < 1 nM) small-molecule BH3 mimetic that inhibits the antiapoptotic proteins Bcl-2, Bcl-x(L) and Bcl-w. The structurally related Bcl-2 inhibitor ABT-737 exhibits single-agent preclinical activity against lymphoma, small-cell lung carcinoma, and chronic lymphocytic leukemia and displays synergistic cytotoxicity with chemotherapeutics and radiation.

Methods: ABT-263 was tested at concentrations ranging from 1.

Reduced immunogenicity of first-trimester human fetal pancreas.

Objective: The use of human fetal pancreatic tissue may provide a potential source of transplantable beta-cells as a therapy for type 1 diabetes. Human fetal pancreas has a remarkable capacity to grow and differentiate in vivo and has been shown to reverse diabetes in rodents. However, it is known that human fetal pancreas obtained from the second trimester of gestation is immunogenic and is rejected after transplantation.

Preclinical chemotherapeutic tumor models of common childhood cancers: solid tumors, acute lymphoblastic leukemia, and disseminated neuroblastoma.

This unit presents three models used in the Pediatric Preclinical Testing Program of the National Cancer Institute (NCI) for preclinical testing of new chemical entities (NCEs), along with appropriate methods for data analysis. The first is the classical subcutaneous xenograft model used for many solid tumors, the second is the disseminated human leukemia model established by Lock and colleagues, and the third is a disseminated model of neuroblastoma that recapitulates many of the characteristics of advanced clinical disease.

A role for altered microtubule polymer levels in vincristine resistance of childhood acute lymphoblastic leukemia xenografts.

The microtubule-depolymerizing drug, vincristine, is effective in the treatment of acute lymphoblastic leukemia (ALL). Although vincristine resistance mechanisms have been extensively characterized in cell lines, their clinical relevance is poorly understood. The aim of the current study was to define clinically relevant mechanisms of vincristine resistance in a panel of childhood ALL xenografts established in immune-deficient (nonobese diabetic/severe combined immunodeficient) mice.

p53 determines multidrug sensitivity of childhood neuroblastoma.

For pediatric cancers like neuroblastoma, the most common extracranial solid tumor of infancy, p53 mutations are rare at diagnosis, but may be acquired after chemotherapy, suggesting a potential role in drug resistance. Heavy metal-selected neuroblastoma cells were found to acquire an unusually broad multidrug resistance (MDR) phenotype but displayed no alterations in genes associated with "classic" MDR. These cells had acquired a mutant p53 gene, linking p53 to drug sensitivity in neuroblastoma.

Initial testing of dasatinib by the pediatric preclinical testing program.

Background: Dasatinib, a dual inhibitor of the src and abl tyrosine kinases, was recently approved by the Federal Drug Administration for the treatment of imatinib mesylate-resistant chronic myeloid leukemia.

Procedures: Dasatinib was tested against the Pediatric Preclinical Testing Program (PPTP) in vitro panel at concentrations ranging from 0.1 nM to 1.

Initial testing (stage 1) of the mTOR inhibitor rapamycin by the pediatric preclinical testing program.

Background: Rapamycin is a highly specific inhibitor of mTOR, a serine/threonine kinase that controls cap-dependent translation. Here we report the activity of rapamycin against the in vitro and in vivo panels of the Pediatric Preclinical Testing Program (PPTP).

Procedures: Rapamycin was tested against the in vitro panel at concentrations from 0.

Preparation of monoclonal antibodies against the spindle checkpoint kinase Bub1.

The Bub1 kinase is a critical component of the spindle checkpoint involved in monitoring the separation of sister chromatids at mitosis. The viral oncoprotein Simian virus 40 large T antigen (LT) can bind and perturb the spindle checkpoint function of Bub1. We have developed three highly specific monoclonal antibodies against the Bub1 protein and have demonstrated that they can all detect Bub1 via Western blotting and immunofluorescence, in addition to their ability to immunoprecipitate Bub1.

In vivo models of childhood leukemia for preclinical drug testing.

The number of new anti-cancer drugs emerging for clinical trials in humans far exceeds the availability of pediatric acute leukemia patients to be entered into clinical trials. Therefore, preclinical testing of new agents for the treatment of childhood acute leukemia is essential to ensure that the most promising drugs are prioritized to enter clinical trials. Historically, the murine system has been central to modeling human leukemia in vivo.

Initial testing of cisplatin by the pediatric preclinical testing program.

Background: Cisplatin is one of the most widely used drugs for the treatment of solid tumors in adults and children. Here, we report the activity of cisplatin against the PPTP panels of childhood cancer xenografts.

Procedures: Cisplatin was evaluated against 23 cell lines, and 40 xenografts representing brain tumors, neuroblastoma, rhabdoid tumors, sarcoma, Wilms tumor, and acute lymphoblastic leukemia (ALL).

C1-inhibitor deficiencies (hereditary angioedema): where are we with therapies?

Hereditary angioedema, an autosomal dominant disorder, presents clinically as recurrent episodes of swelling. It results from either deficient production or function of C1 inhibitor. Acquired angioedema is associated with lymphoproliferative or autoimmune disease.

Activity of vincristine, L-ASP, and dexamethasone against acute lymphoblastic leukemia is enhanced by the BH3-mimetic ABT-737 in vitro and in vivo.

Defects in apoptosis signaling contribute to poor outcome in pediatric acute lymphoblastic leukemia (ALL), and overexpression of antiapoptotic Bcl-2 (Bcl-2 and Bcl-X(L)) family proteins has been observed in ALL. ABT-737 is a small-molecule BH3-mimetic that inhibits the antiapoptotic Bcl-2 family proteins. We evaluated the cytotoxicity of ABT-737 in combination with vincristine, dexamethasone, and L-asparaginase (VXL) in 7 ALL cell lines.