Current Medicinal Chemistry (v.16, #13)

Multiple lines of evidence shows that tumorigenesis is often associated with altered carbohydrate metabolism, characterized by increased glucose uptake and elevated glycolysis, which was first recognized by Otto Warburg 70 years ago. Therefore, the inhibition of glycolysis has been proposed as a therapeutic strategy for cancer treatment. However, this disordered glycotic process does not represent the whole picture of altered energy metabolism during cancer cell transformation. In order to achieve rapid cell proliferation, tumor cells have to constantly accumulate large amount of macromolecules for replication, which has led to several hallmarks of cancer demonstrating its robust metabolic adaptation, including high levels of aerobic glycolysis rate, high rate of energy-consuming processes for syntheses of proteins, DNA and fatty acids. This review summarizes some potential drugable targets as well as their pharmacological inhibitors in glucose, glutamine and fatty acid metabolic pathways. In addition, the upstream oncogenic signaling pathways that are tightly in conjunction with the altered metabolism in tumors are also covered.

Antifungal Drug Discovery through the Study of Invertebrate Model Hosts by R. Pukkila-Worley, E. Holson, F. Wagner, E. Mylonakis (1588-1595).
There is an urgent need for new antifungal agents that are both effective and non-toxic in the therapy of systemic mycoses. The model nematode Caenorhabditis elegans has been used both to elucidate evolutionarily conserved components of host-pathogen interactions and to screen large chemical libraries for novel antimicrobial compounds. Here we review the use of C. elegans models in drug discovery and discuss caffeic acid phenethyl ester, a novel antifungal agent identified using an in vivo screening system. C. elegans bioassays allow high-throughput screens of chemical libraries in vivo. This whole-animal system may enable the identification of compounds that modulate immune responses or affect fungal virulence factors that are only expressed during infection. In addition, compounds can be simultaneously screened for antifungal efficacy and toxicity, which may overcome one of the main obstacles in current antimicrobial discovery. A pilot screen for antifungal compounds using this novel C. elegans system identified 15 compounds that prolonged survival of nematodes infected with the medically important human pathogen Candida albicans. One of these compounds, caffeic acid phenethyl ester (CAPE), was an effective antifungal agent in a murine model of systemic candidiasis and had in vitro activity against several fungal species. Interestingly, CAPE is a potent immunomodulator in mammals with several distinct mechanisms of action. The identification of CAPE in a C. elegans screen supports the hypothesis that this model can identify compounds with both antifungal and host immunomodulatory activity.

Rhodanine as a Privileged Scaffold in Drug Discovery by T. Tomasic, L. Masic (1596-1629).
Rhodanines, thiazolidine-2,4-diones and pseudothiohydantoins have become a very interesting class of heterocyclic compounds since the introduction of various glitazones and epalrestat into clinical use for the treatment of type II diabetes mellitus and diabetic complications, respectively. Chemical modifications of these heterocycles constantly result in compounds with a wide spectrum of pharmacological activities. 5-Arylidenerhodanines are frequently identified as potent hits in high throughput screening against various prokaryotic and eukaryotic targets. Synthesis of substituted rhodanines, based on high throughput screening hits, often leads to potent and selective modulators of targeted enzymes or receptors, which exert their pharmacological activities through different mechanisms of action. Due to various possibilities of chemical derivatization of the rhodanine ring, rhodanine-based compounds will probably remain a privileged scaffold in drug discovery. We have therefore reviewed their biological activities, mechanism of action, structure activity relationship and selectivity against other targets.

Calixarenes in Bio-Medical Researches by Roman Rodik, Vyacheslav Boyko, Vitaly Kalchenko (1630-1655).
Application of calixarene derivatives in bio-medical researches is reviewed in this article. Antiviral, bactericidal, antithrombothic, antituberculosis, anticancer activity as well as specific protein complexation, membranotropic properties and toxicity of modified calixarenes are discussed.

New Developments in Anthracycline-Induced Cardiotoxicity by A. Mordente, E. Meucci, A. Silvestrini, G. Martorana, B. Giardina (1656-1672).
Anthracyclines are among the most effective anticancer drugs ever developed. Unfortunately, their clinical use is severely limited by the development of a progressive dose-dependent cardiomyopathy that irreversibly evolves toward congestive heart failure, usually refractory to conventional therapy. The pathophysiology of anthracycline-induced cardiomyopathy remains controversial and incompletely understood. The current thinking is that anthracyclines are toxic per se but gain further cardiotoxicity after one-electron reduction with ROS overproduction or two-electron reduction with conversion to C-13 alcohol metabolites. ROS overproduction can probably be held responsible for anthracycline acute cardiotoxicity, but not for all the aspects of progressive cardiomyopathy. Intramyocardial formation of secondary alcohol metabolites might play a key role in promoting the progression of cardiotoxicity toward end-stage cardiomyopathy and congestive heart failure. In this review we also discuss recent developments in: a) the molecular mechanisms underlying anthracycline-induced cardiotoxicity; b) the role of cytosolic NADPH-dependent reductases in anthracycline metabolism; c) the influence of genetic polymorphisms on cardiotoxicity outcome; d) the perspectives on the most promising strategies for limiting or preventing anthracycline-induced cardiotoxicity, focusing on controversial aspects and on recent data regarding analogues of the natural compounds, tumor-targeted formulations and cardioprotective agents.

Diaryl esters of and#945;-aminophosphonates are a group of low molecular weight inhibitors of serine proteases. For over 30 years these molecules have captured the attention of biochemists and medicinal chemists due to their similarity to the transition state of peptide bond cleavage observed in enzymatic reactions (transition state analogs) as well as their high potency of action. High reactivity toward serine proteases and complete lack of activity against cysteine or threonine proteases give and#945;-aminophosphonates great advantage over other classes of inhibitors such as chloromethyl ketones or peptidyl derivatives of ketoesters and ketoamides, which are known to react with serine and cysteine proteases. Moreover, the selectivity of and#945;-aminophosphonates' action can be easily adjusted – even for serine proteases with similar specificity a small modification in the inhibitor structure could lead to absolute selectivity towards a particular enzyme. Furthermore and#945;- aminophosphonate derivatives are successfully used as the activity based probes (ABP) for serine protease-like activity screening and as covalently reactive antigens for the development of catalytic antibodies (CAbs). The design of and#945;-aminophosphonate diaryl ester inhibitors focuses on enzymes involved in the development and progression of pathophysiological states in living organisms. Examples include cancer growth and metastasis (urokinase-type plasminogen activator, uPA), diabetes or transplant rejection (dipeptidyl peptidase IV, DPPIV), osteoarthritis and lung injury (elastase) or heart failure (mast cell chymase). This review article focuses on the design of new and#945;-aminophosphonic inhibitors as well as on in vivo studies performed previously using this class of inhibitors and includes recently published research data.