A Repurposing Approach Identifies Off-Patent Drugs with Fungicidal Cryptococcal Activity,a Common Structural Chemotype,and Pharmacological Properties Relevant to the Treatment of Cryptococcosis

New, more accessible therapies for cryptococcosis represent an unmet clinical need of global importance. We took a repurposing approach to identify previously developed drugs with fungicidal activity toward Cryptococcus neoformans, using a high-throughput screening assay designed to detect drugs that directly kill fungi. From a set of 1,120 off-patent medications and bioactive molecules, we identified 31 drugs/molecules with fungicidal activity, including 15 drugs for which direct antifungal activity had not previously been reported. A significant portion of the drugs are orally bioavailable and cross the blood-brain barrier, features key to the development of a widely applicable anticryptococcal agent. Structural analysis of this set revealed a common chemotype consisting of a hydrophobic moiety linked to a basic amine, features that are common to drugs that cross the blood-brain barrier and access the phagolysosome, two important niches of C. neoformans. Consistent with their fungicidal activity, the set contains eight drugs that are either additive or synergistic in combination with fluconazole. Importantly, we identified two drugs, amiodarone and thioridazine, with activity against intraphagocytic C. neoformans. Finally, the set of drugs is also enriched for molecules that inhibit calmodulin, and we have confirmed that seven drugs directly bind C. neoformans calmodulin, providing a molecular target that may contribute to the mechanism of antifungal activity. Taken together, these studies provide a foundation for the optimization of the antifungal properties of a set of pharmacologically attractive scaffolds for the development of novel anticryptococcal therapies.     

Can Antiviral Drugs Contain Pandemic Influenza Transmission?

Antiviral drugs dispensed during the 2009 influenza pandemic generally failed to contain transmission. This poses the question of whether preparedness for a future pandemic should include plans to use antiviral drugs to mitigate transmission.Simulations using a standard transmission model that allows for infected arrivals and delayed vaccination show that attempts to contain transmission require relatively few antiviral doses. In contrast, persistent use of antiviral drugs when the reproduction number remains above 1 use very many doses and are unlikely to reduce the eventual attack rate appreciably unless the stockpile is very large. A second model, in which the community has a household structure, shows that the effectiveness of a strategy of dispensing antiviral drugs to infected households decreases rapidly with time delays in dispensing the antivirals. Using characteristics of past pandemics it is estimated that at least 80% of primary household cases must present upon show of symptoms to have a chance of containing transmission by dispensing antiviral drugs to households. To determine data needs, household outbreaks were simulated with 50% receiving antiviral drugs early and 50% receiving antiviral drugs late. A test to compare the size of household outbreaks indicates that at least 100-200 household outbreaks need to be monitored to find evidence that antiviral drugs can mitigate transmission of the newly emerged virus.Use of antiviral drugs in an early attempt to contain transmission should be part of preparedness plans for a future influenza pandemic. Data on the incidence of the first 350 cases and the eventual attack rates of the first 200 hundred household outbreaks should be used to estimate the initial reproduction number R and the effectiveness of antiviral drugs to mitigate transmission. Use of antiviral drugs to mitigate general transmission should cease if these estimates indicate that containment of transmission is unlikely.     

Network-assisted investigation of antipsychotic drugs and their targets

Antipsychotic drugs are tranquilizing psychiatric medications primarily used in the treatment of schizophrenia and similar severe mental disorders. So far, most of these drugs have been discovered without knowing much on the molecular mechanisms of their actions. The available large amount of pharmacogenetics, pharmacometabolomics, and pharmacoproteomics data for many drugs makes it possible to systematically explore the molecular mechanisms underlying drug actions. In this study, we applied a unique network-based approach to investigate antipsychotic drugs and their targets. We first retrieved 43 antipsychotic drugs, 42 unique target genes, and 46 adverse drug interactions from the DrugBank database and then generated a drug-gene network and a drug-drug interaction network. Through drug-gene network analysis, we found that seven atypical antipsychotic drugs tended to form two clusters that could be defined by drugs with different target receptor profiles. In the drug-drug interaction network, we found that three drugs (zuclopenthixol, ziprasidone, and thiothixene) tended to have more adverse drug interactions than others, while clozapine had fewer adverse drug interactions. This investigation indicated that these antipsychotics might have different molecular mechanisms underlying the drug actions. This pilot network-assisted investigation of antipsychotics demonstrates that network-based analysis is useful for uncovering the molecular actions of antipsychotics.     

Combination of Two but Not Three Current Targeted Drugs Can Improve Therapy of Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a cancer of the hematopoietic system and has been treated with the drug Imatinib relatively successfully. Drug resistance, acquired by mutations, is an obstacle to success. Two additional drugs are now considered and could be combined with Imatinib to prevent resistance, Dasatinib and Nilotinib. While most mutations conferring resistance to one drug do not confer resistance to the other drugs, there is one mutation (T315I) that induces resistance against all three drugs. Using computational methods, the combination of two drugs is found to increase the probability of treatment success despite this cross-resistance. Combining more than two drugs, however, does not provide further advantages. We also explore possible combination therapies using drugs currently under development. We conclude that among the targeted drugs currently available for the treamtent of CML, only the two most effective ones should be used in combination for the prevention of drug resistance.     

Kinetics and mechanisms of cholesterol esterase inhibition by cardiovascular drugs in vitro

Cardiovascular drugs such as lovastatin, simvastatin, amlodipine besylate, nifedipine, and hydralazine hydrochloride inhibit cholesterol esterase (CEase) in vitro. In the present paper, an attempt was made to determine kinetically the reaction mechanism for CEase inhibition by these drugs. The inhibition constant, Ki, for the mixed-type inhibition of CEase by these drugs in the presence of triton-X-100 or taurochloate were measured. Moreover, the pKi values were correlated with the molecular weights of these drugs. In conclusion, the fact that these drugs lower cholesterol levels in the plasma low-density lipoprotein may be partially due to the CEase inhibition by these drugs.     

作用于细胞壁的抗真菌药物研究进展

与人类细胞相比,细胞壁为真菌的特有结构,因此作用于细胞壁的抗真菌药物相较于其他类型抗真菌药物而言具有高效、低毒的特点,是迄今为止安全性最高的一类抗真菌药物。本文对作用于细胞壁的抗真菌药物进行综述,根据作用机制及靶点的不同分别介绍葡聚糖合成酶抑制剂、几丁质合成酶抑制剂及糖基磷脂酰肌(glycosylphosphatidylinositol,GPI)锚定蛋白抑制剂,对其进行总结和归纳,为相关药物的研发及将来的临床应用前景提供参考。     

Drug-induced apoptosis in yeast

In order to alter the impact of diseases on human society, drug development has been one of the most invested research fields. Nowadays, cancer and infectious diseases are leading targets for the design of effective drugs, in which the primary mechanism of action relies on the modulation of programmed cell death (PCD). Due to the high degree of conservation of basic cellular processes between yeast and higher eukaryotes, and to the existence of an ancestral PCD machinery in yeast, yeasts are an attractive tool for the study of affected pathways that give insights into the mode of action of both antitumour and antifungal drugs. Therefore, we covered some of the leading reports on drug-induced apoptosis in yeast, revealing that in common with mammalian cells, antitumour drugs induce apoptosis through reactive oxygen species (ROS) generation and altered mitochondrial functions. The evidence presented suggests that yeasts may be a powerful model for the screening/development of PCD-directed drugs, overcoming the problem of cellular specificity in the design of antitumour drugs, but also enabling the design of efficient antifungal drugs, targeted to fungal-specific apoptotic regulators that do not have major consequences for human cells.     

Current status and future prospects for epigenetic psychopharmacology

Mounting evidence suggest that epigenetic regulation of brain functions is important in the etiology of psychiatric disorders. These epigenetic regulatory mechanisms, such as DNA methylation and histone acetylation, are influenced by many pharmaceutical compounds including psychiatric drugs. It is therefore of interest to investigate how psychiatric drugs are of influence and what the potential is of new epigenetic drugs for psychiatric disorders. With this targeted review we summarize the current state of knowledge in order to provide insight in this developing field. Several traditional psychiatric drugs have been found to alter the epigenome and in a variety of animal studies, experimental compounds with epigenetic targets have been investigated as potential psychiatric drugs. After discussion of the most relevant epigenetic mechanisms we present the evidence for epigenetic effects for the most relevant classes of drugs.     

A systematic analysis of FDA-approved anticancer drugs

Background

The discovery of novel anticancer drugs is critical for the pharmaceutical research and development, and patient treatment. Repurposing existing drugs that may have unanticipated effects as potential candidates is one way to meet this important goal. Systematic investigation of efficient anticancer drugs could provide valuable insights into trends in the discovery of anticancer drugs, which may contribute to the systematic discovery of new anticancer drugs.

Results

In this study, we collected and analyzed 150 anticancer drugs approved by the US Food and Drug Administration (FDA). Based on drug mechanism of action, these agents are divided into two groups: 61 cytotoxic-based drugs and 89 target-based drugs. We found that in the recent years, the proportion of targeted agents tended to be increasing, and the targeted drugs tended to be delivered as signal drugs. For 89 target-based drugs, we collected 102 effect-mediating drug targets in the human genome and found that most targets located on the plasma membrane and most of them belonged to the enzyme, especially tyrosine kinase. From above 150 drugs, we built a drug-cancer network, which contained 183 nodes (150 drugs and 33 cancer types) and 248 drug-cancer associations. The network indicated that the cytotoxic drugs tended to be used to treat more cancer types than targeted drugs. From 89 targeted drugs, we built a cancer-drug-target network, which contained 214 nodes (23 cancer types, 89 drugs, and 102 targets) and 313 edges (118 drug-cancer associations and 195 drug-target associations). Starting from the network, we discovered 133 novel drug-cancer associations among 52 drugs and 16 cancer types by applying the common target-based approach. Most novel drug-cancer associations (116, 87%) are supported by at least one clinical trial study.

Conclusions

In this study, we provided a comprehensive data source, including anticancer drugs and their targets and performed a detailed analysis in term of historical tendency and networks. Its application to identify novel drug-cancer associations demonstrated that the data collected in this study is promising to serve as a fundamental for anticancer drug repurposing and development.

     

Drug control: a prerequisite for health

The purchase of drugs employs an increasingly large part of the health budget of many Third World countries. Like health care expenditure as a whole, drug spending is heavily biased in favour of urban hospitals, often for expensive proprietary drugs that offer little benefit over cheaper preparations. As a result, because limited funds are available, vaccines and drugs for prevention and primary care are sometimes unavailable, especially in rural areas. The World Health Organization and many individual countries have responded to the problem of drug costs by creating a limited list of drugs considered essential for health care needs. Other methods of curtailing spending on drugs have included tendering for supplies and the establishment of plants to manufacture and formulate drugs. Controls of this type meet enormous resistance from doctors and pharmaceutical manufacturers, but are vital for the implementation of policies for appropriate health care.     

The structure and function of drug pumps

Resistance to drugs has emerged in biological systems as diverse as cancer cells undergoing chemotherapy and microbial pathogens undergoing treatment with antimicrobials. This medical problem is escalating and there is an urgent need for the development of new classes of drugs. In the case of pathogenic bacteria, we are rapidly approaching a scenario where there will be no effective antibiotics in the armoury of drugs available for treating the infectious diseases that these bacteria cause, returning us to the pre-antibiotic era when infectious diseases were rife because they were untreatable. One of the most frequently employed resistance strategies in both prokaryotes and eukaryotes is the transmembrane-protein-catalysed extrusion of drugs from the cell, with these proteins acting like bilge pumps, reducing the intracellular drug concentration to subtoxic levels. There is currently much scientific interest in understanding how these pumps operate, so that we might design transport inhibitors that would block them, allowing a renaissance for drugs that are no longer effective owing to their efflux.     

Unintended Effects of Cardiovascular Drugs on the Pathogenesis of Alzheimer’s Disease

Alzheimer’s disease (AD) is rapidly becoming one of the leading causes of disability and mortality in the elderly. As life-expectancy increases, an increasing number of people will rely on modern medicines to treat age-associated disorders. Among these medications, some might benefit, while others might exacerbate, the pathogenesis of AD. We screened 1,600 FDA approved drugs for β-amyloid (Aβ)-modifying activity and identified drugs that can potentially influence amyloid precursor protein processing. In this study, we focused on cardiovascular drugs and demonstrated that some hypertensive medication can differentially modulate Aβ, both in vitro and in vivo. Our study suggests that some commonly prescribed drugs might exert unintended effects and modulate AD and provides the basis for continuing investigation of the role of individual drugs on a case-by-case basis. This line of investigation will lead to the identification of common medications that are potentially beneficial or detrimental to AD as a reference for physicians to consider when prescribing the most appropriate drugs for their patients, particularly for treating chronic disorders among the growing geriatric population.     

Co-treatment with the anti-malarial drugs mefloquine and primaquine highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition

The purpose of this study was to identify conditions that will increase the sensitivity of resistant cancer cells to anti-mitotic drugs. Currently, atovaquine (ATO), chloroquine (CHL), primaquine (PRI), mefloquine (MEF), artesunate (ART), and doxycycline (DOY) are the most commonly used anti-malarial drugs. Herein, we tested whether anti-malarial drugs can sensitize drug-resistant KBV20C cancer cells. None of the six tested anti-malarial drugs was found to better sensitize the drug-resistant cells compared to the sensitive KB cells. With an exception of DOY, all other anti-malarial drugs tested could sensitize both KB and KBV20C cells to a similar extent, suggesting that anti-malarial drugs could be used for sensitive as well as resistant cancer cells.     

The impact of novel antipsychotic drugs on quality of life among people suffering from schizophrenia

More attention is increasingly being paid to quality of life of people suffering from schizophrenia. The results of numerous clinical trials indicate that novel antipsychotic drugs are as efficient (if not more so) than the conventional drugs. Novel drugs also cause fewer side effects and allow for better quality of life. In order to confirm these thesis we have studied the quality of life of 80 female outpatients in good social remission that have been under psychiatric evaluation for at least six months and were on antipsychotic drugs. Of those 80 outpatients, half were on the conventional medication, while the other half were on the novel antipsychotic drugs. Their life quality was evaluated with the questionnaire "Heinrichs-Hanlon-Carpenter--Quality of life questionnaire", which is one of the most frequently used QL scales. The results demonstrate that the only difference between the two groups lies in the field of social activity. While leaving the question of different influence of novel and conventional drugs open, the authors are trying to find the possible reasons for such results.     

抗糖尿病药物治疗阿尔茨海默病的研究进展

阿尔茨海默病（Alzheimers disease, AD）是以认知缺陷为主要特征的慢性疾病,目前尚无有效根治药物。由于患者数量显著增长,探究治疗AD的药物成为国内外的研究热点。近年流行病学研究表明,2型糖尿病是AD的危险因素,两者具有共同的病理生理机制,如胰岛素抵抗、淀粉样蛋白沉积、Tau蛋白过度磷酸化、炎症反应和氧化应激等。因此,从现有的抗糖尿病药物中筛选AD的治疗药物是目前研究的一种趋势。越来越多的研究已证实降糖药物（如胰岛素、二甲双胍等）具有改善AD病变的有益作用。从AD与2型糖尿病的相关性、抗糖尿病药物治疗AD两个方面综述了抗糖尿病药物治疗AD的研究进展,以期为AD的治疗拓宽思路。     

The enzyme as drug: application of enzymes as pharmaceuticals

Enzymes as drugs have two important features that distinguish them from all other types of drugs. First, enzymes often bind and act on their targets with great affinity and specificity. Second, enzymes are catalytic and convert multiple target molecules to the desired products. These two features make enzymes specific and potent drugs that can accomplish therapeutic biochemistry in the body that small molecules cannot. These characteristics have resulted in the development of many enzyme drugs for a wide range of disorders.