Protease Inhibitors Block Multiple Functions of the NS3/4A Protease-Helicase during the Hepatitis C Virus Life Cycle.

UNLABELLED: Hepatitis C virus (HCV) NS3 is a multifunctional protein composed of a protease domain and a helicase domain linked by a flexible linker. Protease activity is required to generate viral nonstructural (NS) proteins involved in RNA replication. Helicase activity is required for RNA replication, and genetic evidence implicates the helicase domain in virus assembly. Binding of protease inhibitors (PIs) to the protease active site blocks NS3-dependent polyprotein processing but might impact other steps of the virus life cycle. Kinetic analyses of antiviral suppression of cell culture-infectious genotype 1a strain H77S.3 were performed using assays that measure different readouts of the viral life cycle. In addition to the active-site PI telaprevir, we examined an allosteric protease-helicase inhibitor (APHI) that binds a site in the interdomain interface. By measuring nucleotide incorporation into HCV genomes, we found that telaprevir inhibits RNA synthesis as early as 12 h at high but clinically relevant concentrations. Immunoblot analyses showed that NS5B abundance was not reduced until after 12 h, suggesting that telaprevir exerts a direct effect on RNA synthesis. In contrast, the APHI could partially inhibit RNA synthesis, suggesting that the allosteric site is not always available during RNA synthesis. The APHI and active-site PI were both able to block virus assembly soon (<12 h) after drug treatment, suggesting that they rapidly engage with and block a pool of NS3 involved in assembly. In conclusion, PIs and APHIs can block NS3 functions in RNA synthesis and virus assembly, in addition to inhibiting polyprotein processing. IMPORTANCE: The NS3/4A protease of hepatitis C virus (HCV) is an important antiviral target. Currently, three PIs have been approved for therapy of chronic hepatitis C, and several others are in development. NS3-dependent cleavage of the HCV polyprotein is required to generate the mature nonstructural proteins that form the viral replicase. Inhibition of protease activity can block RNA replication by preventing expression of mature replicase components. Like many viral proteins, NS3 is multifunctional, but how PIs affect stages of the HCV life cycle beyond polyprotein processing has not been well studied. Using cell-based assays, we show here that PIs can directly inhibit viral RNA synthesis and also block a late stage in virus assembly/maturation at clinically relevant concentrations.

Defining and Measuring Patient Satisfaction.

Reporting patient satisfaction has become an increasingly common component of studies evaluating treatment outcomes. However the construct of "patient satisfaction" is one that is complex and context dependent. While there is no question that careful, reliable, and valid measurement of this important aspect of patient care is required, tools for achieving this objective have not been fully developed. Measures of patient satisfaction that reflect the unique role of the hand in everyday life will require the same approach to instrument development as has been used to move forward the field of outcome measurement in general.

Discovery of an allosteric mechanism for the regulation of HCV NS3 protein function.

Here we report a highly conserved new binding site located at the interface between the protease and helicase domains of the hepatitis C virus (HCV) NS3 protein. Using a chemical lead, identified by fragment screening and structure-guided design, we demonstrate that this site has a regulatory function on the protease activity via an allosteric mechanism. We propose that compounds binding at this allosteric site inhibit the function of the NS3 protein by stabilizing an inactive conformation and thus represent a new class of direct-acting antiviral agents.

Measurement scales in clinical research of the upper extremity, part 1: general principles, measures of general health, pain, and patient satisfaction.

Measurement is a fundamental cornerstone in all aspects of scientific discovery, including clinical research. To be useful, measurement instruments must meet several key criteria, the most important of which are satisfactory reliability, validity, and responsiveness. Part 1 of this article reviews the general concepts of measurement instruments and describes the measurement of general health, pain, and patient satisfaction.

Measurement scales in clinical research of the upper extremity, part 2: outcome measures in studies of the hand/wrist and shoulder/elbow.

Part 1 of this article outlined the basic characteristics of useful clinical measurement instruments and described scales used to measure general health, pain, and patient satisfaction. Part 2 describes the features of some of the scales most commonly used in clinical research in the hand, wrist, elbow, and shoulder.

The heat shock protein 90 inhibitor, AT13387, displays a long duration of action in vitro and in vivo in non-small cell lung cancer.

A ubiquitously expressed chaperone, heat shock protein 90 (HSP90) is of considerable interest as an oncology target because tumor cells and oncogenic proteins are acutely dependent on its activity. AT13387 (2,4-dihydroxy-5-isopropyl-phenyl)-[5-(4-methyl-piperazin-1-ylmethyl)-1,3-dihydro-isoindol-2-yl] methanone, l-lactic acid salt) a novel, high-affinity HSP90 inhibitor, which is currently being clinically tested, has shown activity against a wide array of tumor cell lines, including lung cancer cell lines. This inhibitor has induced the degradation of specific HSP90 client proteins for up to 7 days in tumor cell lines in vitro. The primary driver of cell growth (mutant epidermal growth factor receptors) was particularly sensitive to HSP90 inhibition. The long duration of client protein knockdown and suppression of phospho-signaling seen in vitro after treatment with AT13387 was also apparent in vivo, with client proteins and phospho-signaling suppressed for up to 72 h in xenograft tumors after treatment with a single dose of AT13387. Pharmacokinetic analyses indicated that while AT13387 was rapidly cleared from blood, its retention in tumor xenografts was markedly extended, and it was efficacious in a range of xenograft models. AT13387's long duration of action enabled, in particular, its efficacious once weekly administration in human lung carcinoma xenografts. The use of longer-acting HSP90 inhibitors, such as AT13387, on less frequent dosing regimens has the potential to maintain antitumor efficacy as well as minimize systemic exposure and unwanted effects on normal tissues.

AT9283, a potent inhibitor of the Aurora kinases and Jak2, has therapeutic potential in myeloproliferative disorders.

Constitutive activation of Janus kinase (Jak) 2 is the most prevalent pathogenic event observed in the myeloproliferative disorders (MPD), suggesting that inhibitors of Jak2 may prove valuable in their management. Inhibition of the Aurora kinases has also proven to be an effective therapeutic strategy in a number of haematological malignancies. AT9283 is a multi-targeted kinase inhibitor with potent activity against Jak2 and Aurora kinases A and B, and is currently being evaluated in clinical trials. To investigate the therapeutic potential of AT9283 in the MPD we studied its activity in a number of Jak2-dependent systems. AT9283 potently inhibited proliferation and Jak2-related signalling in Jak2-dependent cell lines as well as inhibiting the formation of erythroid colonies from haematopoietic progenitors isolated from MPD patients with Jak2 mutations. The compound also demonstrated significant therapeutic potential in vivo in an ETV6-JAK2 (TEL-JAK2) murine leukaemia model. Inhibition of both Jak2 and Aurora B was observed in the model systems used, indicating a dual mechanism of action. Our results suggest that AT9283 may be a valuable therapy in patients with MPD and that the dual inhibition of Jak2 and the Aurora kinases may potentially offer combinatorial efficacy in the treatment of these diseases.

Relationship between school absenteeism and depressive symptoms among adolescents with juvenile fibromyalgia.

OBJECTIVE: To describe school absences in adolescents with Juvenile Primary Fibromyalgia Syndrome (JPFS) and examine the relationship between school absenteeism, pain, psychiatric symptoms, and maternal pain history. METHODS: Adolescents with JPFS (N = 102; mean age 14.96 years) completed measures of pain and depressive symptoms, and completed a psychiatric interview. Parents provided information about the adolescents' school absences, type of schooling, and parental pain history. School attendance reports were obtained directly from schools. RESULTS: Over 12% of adolescents with JPFS were homeschooled. Those enrolled in regular school missed 2.9 days per month on average, with one-third of participants missing more than 3 days per month. Pain and maternal pain history were not related to school absenteeism. However, depressive symptoms were significantly associated with school absences. CONCLUSION: Many adolescents with JPFS experience difficulties with regular school attendance. Long-term risks associated with school absenteeism and the importance of addressing psychological factors are discussed.

Dual-Mechanism ERK1/2 Inhibitors Exploit a Distinct Binding Mode to Block Phosphorylation and Nuclear Accumulation of ERK1/2.

The RAS-regulated RAF-MEK1/2-ERK1/2 signaling pathway is frequently deregulated in cancer due to activating mutations of growth factor receptors, RAS or BRAF. Both RAF and MEK1/2 inhibitors are clinically approved and various ERK1/2 inhibitors (ERKi) are currently undergoing clinical trials. To date, ERKi display two distinct mechanisms of action (MoA): catalytic ERKi solely inhibit ERK1/2 catalytic activity, whereas dual mechanism ERKi additionally prevents the activating phosphorylation of ERK1/2 at its T-E-Y motif by MEK1/2. These differences may impart significant differences in biological activity because T-E-Y phosphorylation is the signal for nuclear entry of ERK1/2, allowing them to access many key transcription factor targets. Here, we characterized the MoA of five ERKi and examined their functional consequences in terms of ERK1/2 signaling, gene expression, and antiproliferative efficacy. We demonstrate that catalytic ERKi promote a striking nuclear accumulation of p-ERK1/2 in KRAS-mutant cell lines. In contrast, dual-mechanism ERKi exploits a distinct binding mode to block ERK1/2 phosphorylation by MEK1/2, exhibit superior potency, and prevent the nuclear accumulation of ERK1/2. Consequently, dual-mechanism ERKi exhibit more durable pathway inhibition and enhanced suppression of ERK1/2-dependent gene expression compared with catalytic ERKi, resulting in increased efficacy across BRAF- and RAS-mutant cell lines.

Treatment of carpal tunnel syndrome.

In September 2008, the Board of Directors of the American Academy of Orthopaedic Surgeons approved a clinical practice guideline on the treatment of carpal tunnel syndrome. This guideline was subsequently endorsed by the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. The guideline makes nine specific recommendations: A course of nonsurgical treatment is an option in patients diagnosed with carpal tunnel syndrome. Early surgery is an option with clinical evidence of median nerve denervation or when the patient so elects. Another nonsurgical treatment or surgery is suggested when the current treatment fails to resolve symptoms within 2 to 7 weeks. Sufficient evidence is not available to provide specific treatment recommendations for carpal tunnel syndrome associated with such conditions as diabetes mellitus and coexistent cervical radiculopathy. Local steroid injection or splinting is suggested before considering surgery. Oral steroids or ultrasound are options. Carpal tunnel release is recommended as treatment. Heat therapy is not among the options to be used. Surgical treatment of carpal tunnel syndrome by complete division of the flexor retinaculum is recommended. Routine use of skin nerve preservation and epineurotomy is not suggested when carpal tunnel release is performed. Prescribing preoperative antibiotics for carpal tunnel surgery is an option. It is suggested that the wrist not be immobilized postoperatively after routine carpal tunnel surgery. It is suggested that instruments such as the Boston Carpal Tunnel Questionnaire and the Disabilities of the Arm, Shoulder, and Hand questionnaire be used to assess patient responses to carpal tunnel syndrome treatment for research.

A structural comparison of inhibitor binding to PKB, PKA and PKA-PKB chimera.

Although the crystal structure of the anti-cancer target protein kinase B (PKBbeta/Akt-2) has been useful in guiding inhibitor design, the closely related kinase PKA has generally been used as a structural mimic due to its facile crystallization with a range of ligands. The use of PKB-inhibitor crystallography would bring important benefits, including a more rigorous understanding of factors dictating PKA/PKB selectivity, and the opportunity to validate the utility of PKA-based surrogates. We present a "back-soaking" method for obtaining PKBbeta-ligand crystal structures, and provide a structural comparison of inhibitor binding to PKB, PKA, and PKA-PKB chimera. One inhibitor presented here exhibits no PKB/PKA selectivity, and the compound adopts a similar binding mode in all three systems. By contrast, the PKB-selective inhibitor A-443654 adopts a conformation in PKB and PKA-PKB that differs from that with PKA. We provide a structural explanation for this difference, and highlight the ability of PKA-PKB to mimic the true PKB binding mode in this case.