Tissue Repair and Fibrosis

Background

Because antileukotrienes may inhibit inflammation, it is plausible that montelukast administered for a long time could suppress skin wheal and flare reaction, and thus, it should be discarded prior to the tests. This study assessed the effect of long-lasting treatment with montelukast alone or in combination with antihistamines on wheal and flare in skin pricks tests (SPT) in patients sensitized to perennial allergens.

Methods

We conducted a 32-week, double-blind, placebo-controlled, cross-over and randomized trial that implicated two arms: arm A, 20 patients received levocetirizine, montelukast with or without levocetirizine or placebo; arm B, 20 patients received desloratadine, montelukast with or without desloratadine or placebo. All treatment periods lasted 6 weeks and were separated by 2-week washouts. At baseline and on the last day of each treatment period, SPT were performed in all participants.

Results

Both levocetirizine and desloratadine in monotherapy, or in combination with montelukast, were effective in reducing wheal and flare in SPT. Monotherapy with montelukast did not change the size of the wheal for either histamine or for house dust mites, in either arm of the study, but significantly reduced the size of flare for histamine in arm A. Addition of montelukast to antihistamine did not exceed efficacy of monotherapy with antihistamine in both arms of the study.

Conclusions

Since the size of wheal determines the results of SPT, montelukast, even taken for a long time, does not have to be discarded prior to the tests.     

Characteristics of metabolic stability and the cell permeability of 2‐pyrimidinyl‐piperazinyl‐alkyl derivatives of 1H‐imidazo[2,1‐f]purine‐2,4(3H,8H)‐dione with antidepressant‐ and anxiolytic‐like activities

A series of 2‐pyrimidinyl‐piperazinyl‐alkyl derivatives of 1H‐imidazo[2,1‐f]purine‐2,4(3H,8H)‐dione has been synthesized in an attempt to discover a new class of psychotropic agents. Compounds were evaluated for their in vitro affinity for serotonin 5‐HT_1A, 5‐HT₇, and phosphodiesterases PDE4 and PDE10. The most potent compound 2‐pyrimidinyl‐1‐piperazinyl‐butyl‐imidazo[2,1‐f]purine‐2,4‐dione ( 4b ) behaved as strong and selective antagonist of 5‐HT_1A. Molecular modeling studies revealed differences in binding mode between compound 4b and buspirone, which might reflect variation of the ligands’ affinity and potency in the 5‐HT_1A receptor. Compound 4b in silico models demonstrated drug‐likeness properties and, contrary to buspirone, showed a metabolic stability in mouse liver microsomes system. Experimentally obtained value of apparent permeability coefficient P_app for 4b in parallel artificial permeability assay indicates the possibility of binding weakly to plasma proteins and high intestinal absorption fraction. Evaluation of the antidepressant‐ and anxiolytic‐like activities of 4b revealed both activities at the same dose of 1.25 mg/kg and seemed to be specific. The antidepressant and/or anxiolytic properties of 4b may be related to its first‐pass effect.     

Genetic modifiers of EGFR dependence in non-small cell lung cancer

Lung adenocarcinomas harboring activating mutations in the epidermal growth factor receptor (EGFR) represent a common molecular subset of non-small cell lung cancer (NSCLC) cases. EGFR mutations predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs) and thus represent a dependency in NSCLCs harboring these alterations, but the genetic basis of EGFR dependence is not fully understood. Here, we applied an unbiased, ORF-based screen to identify genetic modifiers of EGFR dependence in EGFR-mutant NSCLC cells. This approach identified 18 kinase and kinase-related genes whose overexpression can substitute for EGFR in EGFR-dependent PC9 cells, and these genes include seven of nine Src family kinase genes, FGFR1, FGFR2, ITK, NTRK1, NTRK2, MOS, MST1R, and RAF1. A subset of these genes can complement loss of EGFR activity across multiple EGFR-dependent models. Unbiased gene-expression profiling of cells overexpressing EGFR bypass genes, together with targeted validation studies, reveals EGFR-independent activation of the MEK-ERK and phosphoinositide 3-kinase (PI3K)-AKT pathways. Combined inhibition of PI3K-mTOR and MEK restores EGFR dependence in cells expressing each of the 18 EGFR bypass genes. Together, these data uncover a broad spectrum of kinases capable of overcoming dependence on EGFR and underscore their convergence on the PI3K-AKT and MEK-ERK signaling axes in sustaining EGFR-independent survival.The term “oncogene addiction” has been used to describe the phenomenon whereby tumor cells exhibit singular reliance on an oncogene or oncogenic pathway for their survival, despite the accumulation of multiple genetic lesions (1). In non-small cell lung cancer (NSCLC), this principle is perhaps best exemplified with the finding that epidermal growth factor receptor (EGFR) mutations predict response to EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib, and thus represent a dependency in the subset of tumors harboring these alterations (2–6). However, though EGFR-mutant NSCLCs typically respond dramatically to EGFR TKIs, clinical responses are not universal, even within this genetically defined cohort, with the rate of objective response estimated to be ∼71% (5, 6). Furthermore, the overwhelming majority of patients who initially respond to EGFR inhibitors ultimately develop resistance to therapy (7). A deeper understanding of the genetic underpinnings of EGFR addiction, and how EGFR-mutant cells can overcome reliance on EGFR, may improve clinical outcomes.Here, we have applied an unbiased screening approach to identify genetic modifiers of EGFR dependence in NSCLC. Mounting evidence supports the existence of several genetic modifiers of EGFR dependence in EGFR-mutant NSCLC, which can reduce the degree to which these tumors rely on EGFR and thereby contribute to EGFR TKI resistance (8). Examples include amplification of the MET receptor tyrosine kinase (RTK) (9), activation of the NF-κB pathway (8), amplification of the HER2 (ERBB2) RTK (10), amplification of the CRKL gene (11), and activation of the AXL kinase (12). Notably, MET bypass can be reciprocally achieved via EGFR activation in MET-dependent cells (13), and analogous examples of reciprocal kinase switching have been reported in other kinase-driven cancer models (14, 15). These and other findings suggest that compensatory kinase switching may be a more general way in which oncogene-dependent cancers overcome reliance on their primary driver kinase (14, 16), but the full-range of kinases capable of mediating EGFR bypass has not been systematically studied.Recent advances in large-scale functional genetic libraries have made it possible to query a wide range of genetic perturbations for their ability to modulate specific cellular phenotypes in mammalian systems (17, 18). Using the model of EGFR-mutant, erlotinib-sensitive NSCLC cells, we have performed a systematic ORF-based screen to identify kinase and kinase-related genes whose overexpression can complement loss of EGFR activity in an EGFR-dependent context. Our findings indicate broad potential for EGFR substitution in the setting of EGFR dependence, with compensatory mechanisms commonly conferring EGFR-independent activation of the PI3K-AKT and MEK-ERK signaling pathways. Importantly, this approach has recovered known mechanisms of erlotinib resistance as well as identified novel mediators of EGFR bypass in EGFR-mutant NSCLC. These data support the idea that the EGFR-dependent state can be redundantly driven by diverse genetic inputs that commonly converge on shared downstream signaling nodes.     

Serum albumin as a determinant of cortisol release in patients with acute ischemic stroke

ObjectiveAnimal studies demonstrated that protein malnutrition increases pituitary-adrenorcortical activity and leads to excessive cortisol release. The aim of our study was to determine the association between serum albumin and cortisol level in patients with acute ischemic stroke.MethodsFifty-nine patients with first-ever ischemic stroke were included. Serum albumin level was measured within 36 h after stroke symptoms onset. Serum cortisol was measured between 36 and 72 h after stroke onset at 6 a.m., 10 a.m., 6 p.m. and 10 p.m.ResultsThe patients in upper tertile of serum albumin had significantly lower cortisol level measured at 6 a.m. (median with interquartiles: 549.0 [430.4–667.7] nmol/L vs 590.4 [482.8–918.7] nmol/L, P = 0.047) and 10 a.m. (402.8 [344.9–510.4] nmol/L vs 634.6 [482.8–827.7] nmol/L, P < 0.01) than patients in lower and middle tertiles. On logistic regression analysis adjusted for age and stroke severity, patients in lower and middle tertile of serum albumin had about 7-times higher risk of hypercortisolemia than patients in upper tertile (P < 0.01).ConclusionsLow serum albumin level in patients with ischemic stroke is associated with higher serum cortisol level and predisposes to hypercortisolemia.     

Stroke in young diver with patent foramen ovale

Patent foramen ovale (PFO) is the most common cause of right-to-left shunt which carries a significant risk for stroke when associated with venous thrombosis, coagulation abnormalities or other conditions. We present a young male in whom diving was associated with stroke in a subject with otherwise clinically silent PFO.     

Functional analysis of receptor tyrosine kinase mutations in lung cancer identifies oncogenic extracellular domain mutations of ERBB2

We assessed somatic alleles of six receptor tyrosine kinase genes mutated in lung adenocarcinoma for oncogenic activity. Five of these genes failed to score in transformation assays; however, novel recurring extracellular domain mutations of the receptor tyrosine kinase gene ERBB2 were potently oncogenic. These ERBB2 extracellular domain mutants were activated by two distinct mechanisms, characterized by elevated C-terminal tail phosphorylation or by covalent dimerization mediated by intermolecular disulfide bond formation. These distinct mechanisms of receptor activation converged upon tyrosine phosphorylation of cellular proteins, impacting cell motility. Survival of Ba/F3 cells transformed to IL-3 independence by the ERBB2 extracellular domain mutants was abrogated by treatment with small-molecule inhibitors of ERBB2, raising the possibility that patients harboring such mutations could benefit from ERBB2-directed therapy.