Current Pharmaceutical Design - Volume 23, Issue 14, 2017

Background: Fluoropyrimidines are widely used in the treatment of solid tumors and remain the backbone of many combination chemotherapy regimens. Despite their clinical benefit, they are associated with frequent gastrointestinal and hematological toxicities, which often lead to treatment discontinuation. Fluoropyrimidines undergo complex anabolic and catabolic biotransformation. Enzymes involved in this pathway include dihydropyrimidine dehydrogenase (DPD), which breaks down 5-FU and its prodrugs. Candidate gene approaches have demonstrated associations between 5-FU treatment outcomes and germline polymorphisms in DPD. The aim of this review is to report and discuss the latest results on fluoropyrimidine pharmacogenetics. Methods: Literature from PubMed databases and bibliography from retrieved publications have been analyzed according to terms such DPD, DPYD, fluoropyrimdines, polymorphisms, toxicity, pharmacogenetics. Results: To date, many sequence variations have been identified within DPYD gene, although the majority of these have no functional consequences on enzymatic activity. Nowadays, there is a general agreement on the clinical significance of the importance of DPD deficiency in patients who suffer from severe, life-threatening drug toxicity although preemptive testing is not applied to all patients. Conclusion: Considering the published literature, clinicians are strongly encouraged to consider testing for DPD poor metabolizer variants as a rational pre-treatment screening for patients candidate to a fluoropyrimidine-based regimens, in order to prevent toxicities and personalise treatments.

Background: Differences in drug response among patients are common. Most major drugs are effective in only 25 to 60 percent of the patients, in part due to the CYP enzymes, whose activity vary up to 50-fold between individuals for some index metabolic reactions. Several factors affect CYP activity, among which genetic polymorphisms have been studied as the major cause for long time. Age, gender, disease states, and environmental influences such as smoking, concomitant drug treatment or exposure to environmental chemicals are also important. Methods: This article reviews the available literature on multiple phenotypes assessment as an important tool to predict possible therapeutic failures or toxic reactions to conventional drug doses during patient evaluation. Results: Probe drugs can be used in various combinations allowing for the in vivo assessment of multiple pathways of drug metabolism in a single experiment, configuring a new tool known as phenotyping "cocktails". There are several drug cocktails with different advantages and disadvantages. Most of them have sufficient clinical evidence and data validation to support their use in clinical setting as a surrogate for the risk of adverse reaction in the course of therapy, leading to a better balance between efficacy and safety. Conclusion: Probes characteristics and metabolic ratio measurements are important in the evaluation of phenotyping cocktails as near-future applications.

Metabolomics is of the increasing interests in medical research and the study of respiratory diseases. This novel type of small molecule analysis can be performed not only on conventional biological samples such as plasma or urine but also on sputum, bronchoalveolar fluid, exhaled breath condensate or exhaled breath itself (which is particularly relevant for research on respiratory diseases). On one hand, powerful analytical methodologies (including mass spectrometry and nuclear magnetic resonance spectroscopy) are labour-intensive but enable the exhaustive identification of metabolites. On the other hand, electronic noses can be used for exhaled breath analysis. Although the latter devices do not contain metabolite-specific sensors, they produce a condition- or treatment-specific “breathprint” based on pattern recognition. Breath analysis with electronic noses is noninvasive, and can be performed at the bedside in real time. Here, we review the literature on metabolomics studies in respiratory medicine, with a focus on the evaluation of responses to pharmacotherapy.

The human cytochrome P450 (CYP) enzyme CYP4Z1 is a fatty acid hydroxylase which among human CYPs is unique for being much stronger expressed in the mammary gland than in all other tissues. Moreover, it is strongly overexpressed in all subtypes of breast cancer, and some overexpression has also been found in other types of malignancies, such as ovarian, lung, and prostate cancers, respectively. Due to its unique expression pattern it is conceivable that this enzymes' activity might be exploited for a new therapeutic approach. However, the main challenge for a CYP4Z1-based prodrug strategy (CBPS) for the treatment of breast cancer (and possibly other CYP4Z1-positive malignancies) is the identification of candidate prodrugs that can be activated by this enzyme. In this mini-review we summarize the current knowledge about the enzymatic properties of the CYP4Z1 enzyme as well as on the expression pattern of the CYP4Z1 gene in both normal and cancer cells. Moreover, we present the first homology model of this enzyme and give an outlook on its potential use in cancer treatment strategies.

Anhedonia, characterized by a loss of interest and/or pleasure in previously enjoyable activities, is an important diagnostic criterion of Major Depressive Disorder (MDD). Converging evidence implicates a causal relationship between proinflammatory cytokines and behavioural disturbances that characterize anhedonia in the context of MDD. Additionally, anhedonia has been implicated in disturbances of key central dopaminergic modulatory pathways. Emerging research into the roles of tetrahydrobiopterin, a cytokine-targeted co-enzyme in the synthesis of dopamine, and kynurenine, a product of inflammation-sensitive breakdown of tryptophan via indoleamine 2, 3-dioxygenase, have shed new light into the role of inflammation in mediating anhedonic behaviours. The following narrative review is not meant to be comprehensive, but highlights the roles of both tetrahydrobiopterin and kynurenine pathways in anhedonia, and discusses a potential mechanism of action via oxidative stress and excitotoxicity. Treatment implications are discussed, with an emphasis on anti-inflammatories as complements to current treatments of anhedonia and MDD.

Chronic respiratory diseases affect millions of people every day. According to the World Health Organization estimates, ~235 million people suffer from asthma, ~64 million suffer from chronic obstructive pulmonary disease (COPD), and millions more suffer from allergic rhinitis around the world. In recent last years, the first phosphodiesterase 4 (PDE4) inhibitor, roflumilast, was approved as a treatment to reduce the risk of exacerbations in stable and severe COPD associated with chronic bronchitis and a history of exacerbations. PDE4 exists as four subtypes (A, B, C, and D) each with a capacity to degrade cAMP, a second messenger involved in inflammatory responses. PDE4 inhibitors inhibit PDE4 activity, consequently increasing cAMP levels. This results in an anti-inflammatory effect, improving lung function. Roflumilast is a selective and non-specific PDE4 inhibitor, with the potential to inhibit all PDE4 isoforms to some degree. Despite the pharmacological effects of roflumilast, its lack of specificity can induce side effects, such as diarrhea, nausea, and dizziness. Thus, there is a continuing need to develop more specific inhibitors of the individual PDE4 subtypes. PDE4B and D inhibitors have been investigated the most, because the levels of these two subtypes are upregulated in moderate and severe COPD. Current and new evidences show that PDE4B and D inhibitors are the most studied, because their expressions are up-regulated in moderate and severe COPD. This review highlights the major advantages of the selective specific inhibition of PDE4A, B, C, and D versus selective, non-specific inhibitors as treatments for chronic respiratory diseases.

Oral diseases like dental caries and periodontal disease are directly associated with the capability of bacteria to form biofilm. Periodontal diseases have been associated to anaerobic Gram-negative bacteria forming a subgingival plaque (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Biofilm is a complex bacterial community that is highly resistant to antibiotics and human immunity. Biofilm communities are the causative agents of biological developments such as dental caries, periodontitis, peri-implantitis and causing periodontal tissue breakdown. The review recapitulates the latest advancements in treatment of clinical biofilm infections and scientific investigations, while these novel anti-biofilm strategies are still in nascent phases of development, efforts dedicated to these technologies could ultimately lead to anti-biofilm therapies that are superior to the current antibiotic treatment. This paper provides a review of the literature focusing on the studies on biofilm in the oral cavity, formation of dental plaque biofilm, drug resistance of bacterial biofilm and the antibiofilm approaches as biofilm preventive agents in dentistry, and their mechanism of biofilm inhibition.

Background: Anti-inflammatory drugs can be ineffective in treating some inflammatory conditions. Improved drug delivery systems like cyclodextrins (CDs) could enhance their efficacy and safety. Objective: We conducted a systematic review to evaluate the anti-inflammatory activity of compounds complexed in CDs, analyzing whether these complexes improved their pharmacological action. Methods: The search terms ‘Anti-inflammatory Agents’, ‘Cyclodextrins’ and ‘Drug effects’ were used to retrieve articles in SCOPUS, PUBMED, MEDLINE and EMBASE. Results: Forty-four papers were identified. In the in vivo and clinical studies, there was greater efficacy for complexed drugs when compared to control groups or uncomplexed drug, decreasing inflammation and inflammatory mediators. Through a meta-analysis, the preclinical studies demonstrated that the complexed drug had a significantly (p<0.001) greater anti-inflammatory effect than the non-CD-complexed drug. Conclusion: The use of CDs can improve the action of anti-inflammatory compounds and it can also be a way to reduce the side effects, therapeutic doses and toxicity.

Conventional drug delivery systems contain numerous limitations such as limited targeting, low therapeutic indices, poor water solubility, and the induction of drug resistances. In order to overcome the drawbacks of conventional pathway of drug delivery, nanoparticle delivery systems are therefore designed and used as the drug carriers. Nanoparticle based drug delivery systems have been rapidly growing and are being applied to various sections of biomedicine. Drug nanocarriers based on dendrimers, liposomes, self-assembling peptides, watersoluble polymers, and block copolymer micelles are the most extensively studied types of drug delivery systems and some of them are being used in clinical therapy. In particular for cancer therapy, antineoplastic drugs are taking advantage of nanoparticulate drug carriers to improve the cure efficacy. Nanoparticle based drug carriers are capable of improving the therapeutic effectiveness of the drugs by using active targeting for the site-specific delivery, passive targeting mechanisms such as enhanced permeability and retention (EPR), de novo synthesis and uptake of low density liposome in cancer cells or by being water-soluble to improve the suboptimal pharmacokinetics in limited water-soluble delivery methods.

Glioblastoma (GBM) is one of the most devastating brain tumors with poor prognosis and high mortality. Although radical surgical treatment with subsequent radiation and chemotherapy can improve the survival, the efficacy of such regimens is insufficient because the GBM cells can spread and destroy normal brain structures. Moreover, these non-specific treatments may damage adjacent healthy brain tissue. It is thus imperative to develop novel therapies to precisely target invasive tumor cells without damaging normal tissues. Immunotherapy is a promising approach due to its capability to suppress the growth of various tumors in preclinical model and clinical trials. Adoptive cell therapy (ACT) using T cells engineered with chimeric antigen receptor (CAR) targeting an ideal molecular marker in GBM, e.g. epidermal growth factor receptor type III (EGFRvIII) has demonstrated a satisfactory efficacy in treating malignant brain tumors. Here we summarize the recent progresses in immunotherapeutic strategy using CAR-modified T cells oriented to EGFRvIII against GBM.

With the serious problem of multiple drug resistance to antibiotics among pathogenic bacteria spreading across the world over the past 30 years, it is crucial to search for novel inhibitors with distinct modes of action from diverse chemical classes. NAD+-dependent DNA ligases (LigAs) are essential enzymes in bacteria, vital for DNA replication and repair. Additionally, LigAs exclusively exist in eubacteria and some viruses and are not found in humans. Those enzymes have therefore been identified as attractive antibacterial drug targets. In this review we explore the discovered inhibitors of LigA through high-throughput screening or virtual screening respectively and their further structure optimization.

The potent calcium channel blocker ω-conotoxin MVIIA is a linear cystine-knot peptide with multiple basic amino acids at both termini. This work shows that macrocyclization of MVIIA linking two positive-charge terminal clusters as a contiguous segment converts a conotoxin into an antimicrobial peptide. In addition, conversion of disulfide bonds to amino butyric acids improved the antimicrobial activity of the cyclic analogs. Ten macrocyclic analogs, with or without disulfide bonds, were prepared by both Boc and Fmoc chemistry using native chemical ligation. All cyclic analogs were active against selected Gram-positive and Gram-negative bacteria with minimal inhibitory concentrations in a low μM range. In contrast, MVIIA and its linear analog were inactive at concentrations up to 0.5 mM. The cyclic analogs also showed 2 to 3-fold improved chemotactic activity against human monocytes THP-1 compared with MVIIA. Reduction of molecular stability against thermal and acid treatment due to the reduced number of disulfide crosslinks can be partly restored by backbone cyclization. Together, these results show that macrocyclization and side chain modification of a linear conopeptide lead to a gain-of-function, which brings a new perspective in designing and engineering of peptidyl therapeutics.

Background: Fruits and vegetables are rich in plant polyphenols, whose consumption is encouraged in healthy dietary regimes due to their antioxidants and anti-inflammatory effects. These organic molecules exhibit numerous properties including phylochelation; the ability to complex metal ions, including highly reactive iron. Among polyphenols, we focused our attention on quercetin that previously demonstrated its ability to reduce dendritic cells (DCs) inflammatory cytokine secretion and antigen presentation following LPS exposure. Dendritic cell inflammatory response is also associated with modulation of several iron metabolism related genes. Objective: To characterize the axis between quercetin exposure and iron extracellular transport that may explain polyphenol anti-inflammatory abilities. Method: Bone marrow derived DCs were exposed to 25μM of quercetin on day 7 and treated with 1 μg/mL of LPS on day 8. The relation between quercetin exposure and the expression level of genes involved in iron homeostasis was addressed by qPCR. The axis between iron export and quercetin exposure was confirmed in vitro and in vivo using quercetin gavage and quercetin-enriched diet. Results: Here we demonstrate that DCs, exposed to quercetin, activate a pattern of genes that increase extracellular iron export, resulting in an overall decrease in the intracellular iron content and consequent diminished inflammatory abilities. This DCs phenotype is consistent with anti-inflammatory phenotype of the mucosal resident DCs, the ones most commonly exposed to polyphenols. Conclusions: Iron balance is a crucial checkpoint for DCs inflammatory abilities. Quercetin-enriched nutritional regimes that favor DCs extracellular iron transport could reduce the incidence of chronic inflammatory syndromes.

Bacterial resistance to conventional antibiotics is an increasingly serious threat to public health worldwide that requires immediate exploration and the development of novel antimicrobial compounds. Drug repurposing is an inexpensive and untapped source of new antimicrobial leads, and it holds many attractive features warranting further attention for antimicrobial drug discovery. In an effort to repurpose drugs and explore new leads in the field of antimicrobial drug discovery, we performed a whole-cell screening assay of 1,600 Food and Drug Administration (FDA) approved drugs against Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (ESKAPE) pathogens. The in vitro screening identified 49 non-antimicrobial drugs that were active against at least one species of ESKAPE pathogen. Although some of these drugs were known to have antibacterial activity, many have never been reported before. In particular, sulfonamide-containing structures represent a novel drug scaffold that should be investigated further. The characteristics of these drugs as antimicrobial agents may offer a safe, effective, and quick supplement to current approaches to treating bacterial infections.