Long-acting beta2-adrenergic formoterol and salmeterol induce the apoptosis of B-chronic lymphocytic leukaemia cells

Complex roles of cAMP-PKA-CREB signaling in cancer

Cyclic adenosine monophosphate (cAMP) is the first discovered second messenger, which plays pivotal roles in cell signaling, and regulates many physiological and pathological processes. cAMP can regulate the transcription of various target genes, mainly through protein kinase A (PKA) and its downstream effectors such as cAMP-responsive element binding protein (CREB). In addition, PKA can phosphorylate many kinases such as Raf, GSK3 and FAK. Aberrant cAMP-PKA signaling is involved in various types of human tumors. Especially, cAMP signaling may have both tumor-suppressive and tumor-promoting roles depending on the tumor types and context. cAMP-PKA signaling can regulate cancer cell growth, migration, invasion and metabolism. This review highlights the important roles of cAMP-PKA-CREB signaling in tumorigenesis. The potential strategies to target this pathway for cancer therapy are also discussed.

The current status of anti-GPCR drugs against different cancers

G protein coupled receptors (GPCRs) have emerged as the most potential target for a number of drug discovery programs ranging from control of blood pressure, diabetes, cure for genetic diseases to treatment of cancer. A panel of different ligands including hormones, peptides, ions and small molecules is responsible for activation of these receptors. Molecular genetics has identified key GPCRs, whose mutations or altered expressions are linked with tumorgenicity. In this review, we discussed recent advances regarding the involvement of GPCRs in the development of cancers and approaches to manipulating the mechanism behind GPCRs involved tumor growth and metastasis to treat different types of human cancer. This review provides an insight into the current scenario of GPCR-targeted therapy, progress to date and the challenges in the development of anticancer drugs.

Short-term benefit of smoking cessation along with glycopirronium on lung function and respiratory symptoms in mild COPD patients: a retrospective study

INTRODUCTION

Tobacco smoke is the leading cause of chronic obstructive pulmonary disease (COPD). Smoking cessation can change the natural history of COPD, as we know from the GOLD guidelines. Little is known about the short-term clinical and functional effects of smoking cessation treatment combined with anti-muscarinic bronchodilators.

OBJECTIVE

To determine whether quitting smoking, obtained by smoking cessation treatment combined with the use of a new long-acting muscarinic antagonist bronchodilator (LAMA), can improve lung function tests and respiratory symptoms more than the use of LAMA alone.

METHODS

We evaluated, in a retrospective analysis, the functional and clinical data, collected in one year, of 120 patients who were current smokers affected by mild COPD and who quit smoking using smoking cessation treatment combined with glycopirronium. We compared them with a group of 80 patients with mild COPD undergoing the same treatment but who did not quit smoking. All patients underwent functional and clinical tests at baseline and at a third-month check.

MEASUREMENTS AND MAIN RESULTS

The two groups were homogeneous in terms of demographic data without significant differences. All patients used varenicline for smoking cessation. They all performed the following tests: a spirometry with detection of resistances, the 6 min walking test, haemogasanalysis, the exhaled CO test, the COPD assessment test (CAT) and finally the modified Medical Research Council test (mMRC). A significant improvement in the functional tests at the third-month check was found in both groups-quitters and non-quitters. However, a notable increase in the examined parameters was registered in the group of patients who quit smoking, in particular, we observed a significant increase at the third-month check of the parameter forced expiratory volume in 1 s (FEV1) of more than 200 ml with p < 0.001. A comparison between quitters and non-quitters revealed a major benefit derived from smoking cessation in terms of functional changes and symptom relief. In particular, not only FEV1 but also forced expiratory flow at 25%-75% of vital capacity (FEF 25-75) (p < 0.01) and CAT (p < 0.001) were found to be significantly improved in patients who quit than in patients who did not at the check time point.

CONCLUSIONS

Smoking cessation treatment obtained by varenicline was confirmed as a crucial therapeutic option, especially when combined with bronchodilator in mild COPD. Patients who quit smoking could already benefit from both treatments in the short term, improving lung function and respiratory symptoms and therefore improving their quality of life.

The role of G protein-coupled receptors in lymphoid malignancies

B cell lymphoma consists of multiple individual diseases arising throughout the lifespan of B cell development. From pro-B cells in the bone marrow, through circulating mature memory B cells, each stage of B cell development is prone to oncogenic mutation and transformation, which can lead to a corresponding lymphoma. Therapies designed against individual types of lymphoma often target features that differ between malignant cells and the corresponding normal cells from which they arise. These genetic changes between tumor and normal cells can include oncogene activation, tumor suppressor gene repression and modified cell surface receptor expression. G protein-coupled receptors (GPCRs) are an important class of cell surface receptors that represent an ideal target for lymphoma therapeutics. GPCRs bind a wide range of ligands to relay extracellular signals through G protein-mediated signaling cascades. Each lymphoma subgroup expresses a unique pattern of GPCRs and efforts are underway to fully characterize these patterns at the genetic level. Aberrations such as overexpression, deletion and mutation of GPCRs have been characterized as having causative roles in lymphoma and such studies describing GPCRs in B cell lymphomas are summarized here.

Targeting cAMP in chronic lymphocytic leukemia: a pathway-dependent approach for the treatment of leukemia and lymphoma

INTRODUCTION

Cyclic AMP (cAMP) promotes growth arrest and/or apoptosis of various types of lymphoma, in particular chronic lymphocytic leukemia (CLL). These responses have spurred the interest in developing agents that increase cAMP to treat such malignancies and to identify mechanisms of the responses.

AREAS COVERED

The murine T-lymphoma cell line S49, has provided an important, pioneering model to define mechanisms of cAMP-mediated lymphoid cell death. Studies with S49 cells demonstrated that cAMP, acting via protein kinase A (PKA), is pro-apoptotic through a mitochondria-dependent pathway and identified cAMP/PKA-regulated targets involved in apoptosis. Akin to such findings, cAMP promotes apoptosis via PKA of cells from patients with CLL. Analysis of mediators of cAMP accumulation and cAMP-promoted apoptosis in CLL cells has revealed approaches to increase cAMP and engage its pro-apoptotic action.

EXPERT OPINION

This 'pathway approach' targeted to cAMP has identified GPCR agonists/antagonists, AC activators (e.g., AC7), PDE inhibitors (e.g., PDE7B) and/or activators or inhibitors of downstream mediators (PKA and Epac, respectively), which might be utilized therapeutically in CLL. Therapy directed at such targets may prove to be clinically useful and may also provide a proof-of-principle of the utility of targeting cAMP signaling in other types of cancer.

Neurotransmitters as regulators of tumor angiogenesis and immunity: the role of catecholamines

The growing tumor employs various strategies to establish its growth, progression and spread in the host. Angiogenesis or formation of new blood vessels from existing ones and escape from immune surveillance are the two critical steps that ensure proper establishment and growth of the newly formed tumor. Thus understanding the novel pathways associated with tumor angiogenesis and immunity may lead to the development of newer therapeutic strategies using the regulators of these pathways to improve patient outcomes. These two pivotal steps in the process of tumorigenesis are governed by plethora of endogenous factors. The neuroendocrine molecules, which include the catecholamine neurotransmitters, dopamine, norepinephrine and epinephrine are of growing interest considering their varied and diverse regulatory roles both in the process of tumor angiogenesis and tumor immunity. This review focuses on the emerging roles of catecholamines in modulating tumor angiogenesis and immunity, and also discusses the probable molecular mechanisms of their actions. Understanding of this new group of endogenous regulators of tumor growth may lead to the development of newer therapeutic approaches for the treatment of cancer.

Chronic stress enhances progression of acute lymphoblastic leukemia via β-adrenergic signaling

Clinical studies suggest that stress-related biobehavioral factors can accelerate the progression of hematopoietic cancers such as acute lymphoblastic leukemia (ALL), but it is unclear whether such effects are causal or what biological pathways mediate such effects. Given the network of sympathetic nervous system (SNS) fibers that innervates the bone marrow to regulate normal (non-leukemic) hematopoietic progenitor cells, we tested the possibility that stress-induced SNS signaling might also affect ALL progression. In an orthotopic mouse model, Nalm-6 human pre-B ALL cells were transduced with the luciferase gene for longitudinal bioluminescent imaging and injected i.v. into male SCID mice for bone marrow engraftment. Two weeks of daily restraint stress significantly enhanced ALL tumor burden and dissemination in comparison to controls, and this effect was blocked by the β-adrenergic antagonist, propranolol. Although Nalm-6 ALL cells expressed mRNA for β1- and β3-adrenergic receptors, they showed no evidence of cAMP signaling in response to norepinephrine, and norepinephrine failed to enhance Nalm-6 proliferation in vitro. These results show that chronic stress can accelerate the progression of human pre-B ALL tumor load via a β-adrenergic signaling pathway that likely involves indirect regulation of ALL biology via alterations in the function of other host cell types such as immune cells or the bone marrow microenvironment.

Increased corticosteroid sensitivity by a long acting β2 agonist formoterol via β2 adrenoceptor independent protein phosphatase 2A activation

Long-acting β2-adrenoceptor agonists (LABAs) are reported to enhance anti-inflammatory effects of corticosteroids in vitro and in vivo, although the molecular mechanisms have not yet been elucidated. We investigated the role of serine/threonine protein phosphatase 2A (PP2A) on regulation of corticosteroid sensitivity via inhibition of glucocorticoid receptor (GR) phosphorylation as the target of formoterol, an LABA. Corticosteroid sensitivity was determined as IC50 to dexamethasone (Dex) on TNFα-induced IL-8 release in a U937 monocytic cell line (Dex-IC50). Phosphorylation levels of GR-Ser226 and c-Jun N-terminal kinase (JNK) were determined by western-blotting. Phosphatase activity of immunopurified PP2A was measured by fluorescence-based assay. Exposure to IL-2/IL-4 for 48 h decreased Dex sensitivity with a concomitant increase of GR phosphorylation at Ser226 with JNK1 activation. Formoterol restored Dex sensitivity by inhibiting phosphorylation of GR-Ser226 and JNK1. PP2A inhibition by okadaic acid, a phosphatase inhibitor, abrogated formoterol-mediated effects. In addition, formoterol enhanced PP2A activity in intact or IL-2/IL-4 treated U937 cells and human peripheral blood mononuclear cells. In addition, PP2A activation by formoterol was not antagonized by ICI-118551, and formoterol could activate PP2A directly in cell free system. Taken together, formoterol increases corticosteroid sensitivity via activation of PP2A in receptor independent manner, explaining its benefits as add-on therapy for the treatment of corticosteroid-insensitive diseases, such as severe asthma.

Adrenergic modulation of immune cells: an update

Sympathoadrenergic pathways are crucial to the communication between the nervous system and the immune system. The present review addresses emerging issues in the adrenergic modulation of immune cells, including: the specific pattern of adrenoceptor expression on immune cells and their role and changes upon cell differentiation and activation; the production and utilization of noradrenaline and adrenaline by immune cells themselves; the dysregulation of adrenergic immune mechanisms in disease and their potential as novel therapeutic targets. A wide array of sympathoadrenergic therapeutics is currently used for non-immune indications, and could represent an attractive source of non-conventional immunomodulating agents.

Elaborate ligand-based modeling reveals new nanomolar heat shock protein 90α inhibitors

Heat shock protein (Hsp90α) has been recently implicated in cancer prompting several attempts to discover and optimize new Hsp90α inhibitors. Toward this end, we explored the pharmacophoric space of 83 Hsp90α inhibitors using six diverse sets of inhibitors to identify high-quality pharmacophores. Subsequently, genetic algorithm and multiple linear regression analysis were employed to select an optimal combination of pharmacophoric models and 2D physicochemical descriptors capable of accessing a self-consistent quantitative structure activity relationship (QSAR) of optimal predictive potential (r(67)(2)=0.811, F 42.8, r(LOO)(2)=0.748, r(PRESS)(2) (against 16 external test inhibitors) = 0.619). Three orthogonal pharmacophores emerged in the QSAR equation suggesting the existence of at least three binding modes accessible to ligands within the Hsp90α binding pocket. Receiver operating characteristic (ROC) curves analysis established the validity of QSAR-selected pharmacophores. We employed the pharmacophoric models and associated QSAR equation to screen the national cancer institute (NCI) list of compounds and our in-house-built drugs and agrochemicals database (DAC). Twenty-five nanomolar and low micromolar Hsp90α inhibitors were identified. The most potent were formoterol, amodaquine, primaquine, and midodrine with IC(50) values of 3, 5, 6, and 20 nM, respectively.

Prognostic factors for 100 patients with malignant pleural mesothelioma

The aim of this study was to investigate the effects of various clinical, laboratory characteristics, and therapeutic modalities on the survival of patients with malignant pleural mesothelioma. One hundred consecutive patients with a pathologically proven diagnosis of malignant pleural mesothelioma treated between 1993 and 2005 were included in the study. Using a Cox proportional hazard model, comorbidity, weight loss, breathlessness, and performance status were identified as independent prognostic factors. Comorbidity had interestingly favorable effect on the survival. Treated patients with chemotherapy had significantly longer survival than those treated with best supportive care. However, it was necessary to complete at least 6 cycles for a survival benefit. In conclusions, comorbidity information should be recorded in the recent prognostic studies. The drugs used for the comorbidity may improve survival.

Mechanisms of drug combinations: interaction and network perspectives

Understanding the molecular mechanisms underlying synergistic, potentiative and antagonistic effects of drug combinations could facilitate the discovery of novel efficacious combinations and multi-targeted agents. In this article, we describe an extensive investigation of the published literature on drug combinations for which the combination effect has been evaluated by rigorous analysis methods and for which relevant molecular interaction profiles of the drugs involved are available. Analysis of the 117 drug combinations identified reveals general and specific modes of action, and highlights the potential value of molecular interaction profiles in the discovery of novel multicomponent therapies.