Rapid in vitro activity of telavancin against Bacillus anthracis and in vivo protection against inhalation anthrax infection in the rabbit model.

Inhalation anthrax is the most severe form of Bacillus anthracis infection, often progressing to fatal conditions if left untreated. While recommended antibiotics can effectively treat anthrax when promptly administered, strains engineered for antibiotic resistance could render these drugs ineffective. Telavancin, a semisynthetic lipoglycopeptide antibiotic, was evaluated in this study as a novel therapeutic against anthrax disease. Specifically, the aims were to (i) assess in vitro potency of telavancin against 17 B. anthracis isolates by minimum inhibitory concentration (MIC) testing and (ii) evaluate protective efficacy in rabbits infected with a lethal dose of aerosolized anthrax spores and treated with human-equivalent intravenous telavancin doses (30 mg/kg every 12 hours) for 5 days post-antigen detection versus a humanized dose of levofloxacin and vehicle control. Blood samples were collected at various times post-infection to assess the level of bacteremia and antibody production, and tissues were collected to determine bacterial load. The animals' body temperatures were also recorded. Telavancin demonstrated potent bactericidal activity against all strains tested (MICs 0.06-0.125 µg/mL). Further, telavancin conveyed 100% survival in this model and cleared B. anthracis from the bloodstream and organ tissues more effectively than a humanized dose of levofloxacin. Collectively, the low MICs against all strains tested and rapid bactericidal in vivo activity demonstrate that telavancin has the potential to be an effective alternative for the treatment or prophylaxis of anthrax infection.

B-cell receptor pathobiology and targeting in NHL.

B-cell receptor signaling plays varied and critical roles in B-cell development, homeostasis and disease. The key players of the pathway and its many signaling modulators have been identified as well as some of the mechanisms by which the pathway is regulated. With the increased incidence of non-Hodgkin's lymphoma in recent years, there is a clear clinical need for novel agents to offer new options in resistant disease to potentially improve outcomes in curative settings. With the tremendous insight gained in the last 2 decades from basic science research, our understanding of the pathobiology of the B-cell receptor is leading to the discovery and clinical development of many new therapeutic targets such as Syk, Bruton's tyrosine kinase, and phosphatidylinositol 3-kinase. This review will emphasize contemporary and salient findings on novel agents targeting the B-cell receptor signaling pathway for the treatment of non-Hodgkin's lymphoma.

Intravenous Ibuprofen Reduces Opioid Consumption During the Initial 48 Hours After Injury in Orthopedic Trauma Patients.

OBJECTIVES: To evaluate the efficacy of intravenous (IV) ibuprofen (Caldolor) administration in the management of acute pain in orthopedic trauma patients and to minimize opioid use. DESIGN: Randomized controlled trial, double-blind, parallel, placebo-controlled. SETTING: Level 1 Trauma Center. PATIENTS: A total of 99 consecutive orthopedic trauma patients with fractures of the ribs, face, extremities, and/or pelvis were randomized to receive either 800 mg IV ibuprofen (53 patients) or placebo (44 patients) administered every 6 hours for a total of 8 doses within 48 hours of admission and the same PRN medications along with 20-mg IV/PO Pepcid twice a day. To establish pain reduction efficacy, the analysis was consequently performed in the modified intent-to-treat group that included 74 randomized subjects with a baseline pain score greater than 2. The primary outcomes were reduction in opioid consumption and decrease in pain intensity (PI). INTERVENTION: Administration of study medications. OUTCOME MEASUREMENTS: PI measured by Numerical Rating Scale, opioid consumption adjusted to morphine equivalent dose, and time to first narcotic administration. RESULTS: The 2 groups had comparable baseline characteristics: age, sex distribution, mechanism of injury, type of injury, injury severity score, and PI. IV ibuprofen statistically significantly reduced opioid consumption compared with placebo during the initial 48-hour period (P = 0.017). PI calculated as PI differences was statistically different only at 8-hour interval after Caldolor administration. Time to first narcotic medication was significantly longer in the Caldolor group (hazard ratio: 1.640; 95% confidence interval, 1.009-2.665; P = 0.046). CONCLUSIONS: IV ibuprofen provided adequate analgesia, prolonged time to first narcotic administration, and was opioid-sparing for the treatment of pain in orthopedic trauma patients, which makes Caldolor a recommended candidate for managing acute pain in the diverse orthopaedic trauma population. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Antagonism of the Thromboxane-Prostanoid Receptor as a Potential Therapy for Cardiomyopathy of Muscular Dystrophy.

Background Muscular dystrophy (MD) causes a progressive cardiomyopathy characterized by diffuse fibrosis, arrhythmia, heart failure, and early death. Activation of the thromboxane-prostanoid receptor (TPr) increases calcium transients in cardiomyocytes and is proarrhythmic and profibrotic. We hypothesized that TPr activation contributes to the cardiac phenotype of MD, and that TPr antagonism would improve cardiac fibrosis and function in preclinical models of MD. Methods and Results Three different mouse models of MD (mdx/utrn double knockout, second generation mdx/mTR double knockout, and delta-sarcoglycan knockout) were given normal drinking water or water containing 25 mg/kg per day of the TPr antagonist ifetroban, beginning at weaning. After 6 months (10 weeks for mdx/utrn double knockout), mice were evaluated for cardiac and skeletal muscle function before euthanization. There was a 100% survival rate of ifetroban-treated mice to the predetermined end point, compared with 60%, 43%, and 90% for mdx/utrn double knockout, mdx/mTR double knockout, and delta-sarcoglycan knockout mice, respectively. TPr antagonism improved cardiac output in mdx/utrn double knockout and mdx/mTR mice, and normalized fractional shortening, ejection fraction, and other parameters in delta-sarcoglycan knockout mice. Cardiac fibrosis in delta-sarcoglycan knockout was reduced with TPr antagonism, which also normalized cardiac expression of claudin-5 and neuronal nitric oxide synthase proteins and multiple signature genes of Duchenne MD. Conclusions TPr antagonism reduced cardiomyopathy and spontaneous death in mouse models of Duchenne and limb-girdle MD. Based on these studies, ifetroban and other TPr antagonists could be novel therapeutics for treatment of the cardiac phenotype in patients with MD.

Fewer adverse effects associated with a modified two-bag intravenous acetylcysteine protocol compared to traditional three-bag regimen in paracetamol overdose.

Context: The intravenous (IV) N-acetylcysteine (NAC) regimen used worldwide in paracetamol overdose is complex with three separate weight-based doses and is associated with a high incidence of adverse events including non-allergic anaphylactoid reactions (NAARs). In 2012, Denmark adopted the two-bag IV NAC regimen which combined the first two infusions of the three-bag regimen and kept the third infusion unchanged. We compared the safety and efficacy of the two-bag IV NAC regimen with the traditional Danish three-bag regimen. Methods: A medical chart review was conducted in three Danish medical centers from January 2012 through December 2014. Safety and efficacy data were compared for patients who received the traditional infusion protocol in Denmark or the 20-h two-bag IV regimen. Results: Four hundred and ninety-three cases received the two-bag regimen and 274 received the three-bag regimen. The overall incidence of NAARs was 9% with all being mild to moderate in intensity. Fewer subjects in the two-bag group (4%) developed NAARs compared to 17% in the three-bag group (p < .001). Overall, 31 patients (4%) developed hepatotoxicity. There was no apparent difference in hepatotoxicity rates between the groups and no deaths or liver transplants. Patients receiving the two-bag regimen had fewer interruptions or delays (5%) compared to the three-bag regimen cohort (12%). Overall, there were very few medication errors reported (1%). Conclusions: The incidence of NAARs was lower in patients receiving acetylcysteine in a two-bag regimen compared to the traditional Danish three-bag regimen without an apparent reduction in efficacy.

GS-1101: a delta-specific PI3K inhibitor in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) remains an incurable B-cell malignancy with many unanswered questions. While the cell of origin and etiology are still unknown, significant scientific progress has revealed numerous molecular targets for novel therapeutic interventions. Phosphatidylinositol 3-kinases (PI3K) regulate key cellular functions, including growth, survival and migration, by integrating and transmitting signals from diverse surface molecules including the B-cell receptor (BCR). In lymphocytes, the PI3Kδ isoform plays a critical role in B-cell homeostasis and function. In CLL, the PI3K pathway is constitutively active and dependent on PI3Kδ. GS-1101 is a highly selective PI3Kδ inhibitor that in CLL patients causes a rapid and sustained reduction in lymphadenopathy, accompanied by transient lymphocytosis. This article will review new insights into the pathophysiology of CLL, the preclinical rationale of a PI3Kδ inhibitor in CLL, and the clinical evidence supporting this first-in-class therapeutic target for CLL patients.

Oxaliplatin and capecitabine in the treatment of patients with recurrent or refractory carcinoma of unknown primary site: a phase 2 trial of the Sarah Cannon Oncology Research Consortium.

BACKGROUND: Despite the widespread use of oxaliplatin-based regimens for colorectal and other gastrointestinal cancers, there is surprisingly little information regarding their empiric use for the treatment of carcinoma of unknown primary site (CUP). In the current study, the combination of oxaliplatin and capecitabine in patients with recurrent and refractory CUP was examined. METHODS: Patients with CUP who had received at least 1 previous chemotherapy regimen were treated with oxaliplatin (130 mg/m(2) intravenously on Day 1) and capecitabine (1000 mg/m(2) orally twice daily on Days 1-14). Treatment cycles were repeated every 21 days. Patients with objective response or stable disease after 2 cycles continued treatment for 6 cycles or until disease progression. RESULTS: Nine of 48 patients (19%) had objective responses to treatment; an additional 22 patients had stable disease at the time of first re-evaluation. After a median follow-up of 17 months, the median progression-free and overall survivals were 3.7 months and 9.7 months, respectively. This regimen was reasonably well tolerated by most patients. CONCLUSIONS: The combination of oxaliplatin and capecitabine was found to have activity as a salvage treatment for patients with CUP. This regimen should be considered in patients with clinical and pathologic features suggesting a primary site in the gastrointestinal tract. Further development of the regimen as a first-line therapy, or with bevacizumab added, is indicated.

Mouse EP3 alpha, beta, and gamma receptor variants reduce tumor cell proliferation and tumorigenesis in vivo.

Prostaglandin E(2), which exerts its functions by binding to four G protein-coupled receptors (EP1-4), is implicated in tumorigenesis. Among the four E-prostanoid (EP) receptors, EP3 is unique in that it exists as alternatively spliced variants, characterized by differences in the cytoplasmic C-terminal tail. Although three EP3 variants, alpha, beta, and gamma, have been described in mice, their functional significance in regulating tumorigenesis is unknown. In this study we provide evidence that expressing murine EP3 alpha, beta, and gamma receptor variants in tumor cells reduces to the same degree their tumorigenic potential in vivo. In addition, activation of each of the three mEP3 variants induces enhanced cell-cell contact and reduces cell proliferation in vitro in a Rho-dependent manner. Finally, we demonstrate that EP3-mediated RhoA activation requires the engagement of the heterotrimeric G protein G(12). Thus, our study provides strong evidence that selective activation of each of the three variants of the EP3 receptor suppresses tumor cell function by activating a G(12)-RhoA pathway.

Loss of integrin alpha1beta1 ameliorates Kras-induced lung cancer.

The collagen IV binding receptor integrin alpha1beta1 has been shown to regulate lung cancer due to its proangiogenic properties; however, it is unclear whether this receptor also plays a direct role in promoting primary lung tumors. To investigate this possibility, integrin alpha1-null mice were crossed with KrasLA2 mice that carry an oncogenic mutation of the Kras gene (G12D) and develop spontaneous primary tumors with features of non-small cell lung cancer. We provide evidence that KrasLA2/alpha1-null mice have a decreased incidence of primary lung tumors and longer survival compared with KrasLA2/alpha1 wild-type controls. Tumors from KrasLA2/alpha1-null mice were also smaller, less vascularized, and exhibited reduced cell proliferation and increased apoptosis, as determined by proliferating cell nuclear antigen and terminal deoxynucleotidyl-transferase-mediated dUTP nick-end staining, respectively. Moreover, tumors from the KrasLA2/alpha1-null mice showed diminished extracellular signal-regulated kinase (ERK) but enhanced p38 mitogen-activated protein kinase activation. Primary lung tumor epithelial cells isolated from KrasLA2/alpha1-null mice showed a significant decrease in anchorage-independent colony formation, collagen-mediated cell proliferation, ERK activation, and, most importantly, tumorigenicity when injected into nude mice compared with KrasLA2/alpha1 wild-type tumor cells. These results indicate that loss of the integrin alpha1 subunit decreases the incidence and growth of lung epithelial tumors initiated by oncogenic Kras, suggesting that both Kras and integrin alpha1beta1 cooperate to drive the growth of non-small cell lung cancer in vivo.

Prostaglandin E2-EP4 receptor promotes endothelial cell migration via ERK activation and angiogenesis in vivo.

Prostaglandin E2 (PGE(2)), a major product of cyclooxygenase, exerts its functions by binding to four G protein-coupled receptors (EP1-4) and has been implicated in modulating angiogenesis. The present study examined the role of the EP4 receptor in regulating endothelial cell proliferation, migration, and tubulogenesis. Primary pulmonary microvascular endothelial cells were isolated from EP4(flox/flox) mice and were rendered null for the EP4 receptor with adenoCre virus. Whereas treatment with PGE(2) or the EP4 selective agonists PGE(1)-OH and ONO-AE1-329 induced migration, tubulogenesis, ERK activation and cAMP production in control adenovirus-transduced endothelial EP4(flox/flox) cells, no effects were seen in adenoCre-transduced EP4(flox/flox) cells. The EP4 agonist-induced endothelial cell migration was inhibited by ERK, but not PKA inhibitors, defining a functional link between PGE(2)-induced endothelial cell migration and EP4-mediated ERK signaling. Finally, PGE(2), as well as PGE(1)-OH and ONO-AE1-329, also promoted angiogenesis in an in vivo sponge assay providing evidence that the EP4 receptor mediates de novo vascularization in vivo.

Characterization of 5,6- and 8,9-epoxyeicosatrienoic acids (5,6- and 8,9-EET) as potent in vivo angiogenic lipids.

The cytochrome P450 arachidonic acid epoxygenase metabolites, the epoxyeicosatrienoic acids (EETs) are powerful, nonregioselective, stimulators of cell proliferation. In this study we compared the ability of the four EETs (5,6-, 8,9-, 11,12-, and 14,15-EETs) to regulate endothelial cell proliferation in vitro and angiogenesis in vivo and determined the molecular mechanism by which EETs control these events. Inhibition of the epoxygenase blocked serum-induced endothelial cell proliferation, and exogenously added EETs rescued cell proliferation from epoxygenase inhibition. Studies with selective ERK, p38 MAPK, or PI3K inhibitors revealed that whereas activation of p38 MAPK is required for the proliferative responses to 8,9- and 11,12-EET, activation of PI3K is necessary for the cell proliferation induced by 5,6- and 14,15-EET. Among the four EETs, only 5,6- and 8,9-EET are capable of promoting endothelial cell migration and the formation of capillary-like structures, events that are dependent on EET-mediated activation of ERK and PI3K. Using subcutaneous sponge models, we showed that 5,6- and 8,9-EET are pro-angiogenic in mice and that their neo-vascularization effects are enhanced by the co-administration of an inhibitor of EET enzymatic hydration, presumably because of reduced EET metabolism and inactivation. These studies identify 5,6- and 8,9-EET as powerful and selective angiogenic lipids, provide a functional link between the EET proliferative chemotactic properties and their angiogenic activity, and suggest a physiological role for them in angiogenesis and de novo vascularization.

Colon carcinoma cell growth is associated with prostaglandin E2/EP4 receptor-evoked ERK activation.

Cyclooxygenase (COX) and its prostanoid metabolites have been implicated in the control of cell survival; however, their role as mitogens remains undefined. To better understand the role of prostanoids on cell growth, we used mouse colon adenocarcinoma (CT26) cells to investigate the role of prostaglandin E(2) (PGE(2)) in cell proliferation. CT26 cells express both COX1 and COX2 and metabolize arachidonic acid to PGE(2.) Treatment with indomethacin, or COX-selective inhibitors, prevents PGE(2) biosynthesis and CT26 cell proliferation. The anti-proliferative effects of COX inhibition are rescued specifically by treatment with PGE(2) or the EP4 receptor-selective agonist PGE(1)-OH via phosphatidylinositol 3-kinase/extracellular signal-regulated kinase (ERK) activation, thus providing a functional link between PGE(2)-induced cell proliferation and EP4-mediated ERK signaling. Indomethacin or COX2 inhibitors, but not COX1 inhibitors, reduced the size and number of CT26-derived tumors in vivo. These inhibitory effects are paralleled by marked declines in the levels of tumor PGE(2), suggesting that their anti-tumor effects are directly associated with the inhibition of COX2 enzymatic activity. The described anti-tumor effects of indomethacin are evident whether it is administered at the time of, or 7 days after, tumor cell injection, suggesting that it has tumor preventive and therapeutic actions. Furthermore, the observation that indomethacin increases the survival rates of tumor-bearing mice, even after withdrawal of the drug, indicates that its effects are long lasting and that it may be potentially useful for the prevention and the clinical management of human cancers.