Mini Reviews in Medicinal Chemistry - Volume 8, Issue 5, 2008

Preclinical studies revealed that curcumin, the yellow curry pigment, emodin, a compound derived from grapes, and taurolidine, derived from a biogenic amino acid, and some of their structural homologs possess anti-angiogenic and cancer chemopreventive properties. Whereas curcumin and emodin can act via inhibition of COP9 signalosome-associated kinases, taurolidine blocks protein biosynthesis.

Beta-amyloid (Aβ) likely plays a pivotal role in the etiology of Alzheimer's disease (AD). Consequently, Aβ-associated pathways are targets for the development of possible effective AD therapies. This review first updates strategies aimed at the inhibition of Aβ formation and then discusses the role of food-derived polyphenols as putative antiamyloid drugs.

Natural polyphenols are a wide class of secondary plant metabolites and represent an abundant antioxidant component of human diet. An important, but often neglected group of natural polyphenols, are tannins. This review offers a general description of chemistry of both hydrolysable and condensed tannins (proanthocyanidins), the mechanisms of their antioxidation action, like free radical scavenging activity, chelation of transition metals, inhibition of prooxidative enzymes and lipid peroxidation. The mechanisms of action of antibacterial, antiviral, anticarcinogenic, cardiovascular system preventing, and antiinflammatory effects as well as the absorption, metabolic fate and positive in vivo effects of tannins are enclosed.

The estrogens play important role in the homeostatic maintenance of several target tissues including those in the mammary gland, uterus, bone, cardiovascular system, and brain. Most of estrogen's action is thought to be mediated through its nuclear estrogen receptors, ERα and ERβ, which are members of the nuclear receptor superfamily that act as ligand-induced transcription factors. Acting via its receptors, estrogen also plays an essential role in the development and progression of human breast cancer. The ER and progesterone receptor (PR), which are regulated by estrogen via ER, have been used as prognostic markers in the clinical management of breast cancer patients. However, the prognosis of a patient with ER+/PR+ breast cancer can be highly variable and a significant proportion of hormone receptor positive breast cancers does not respond to endocrine therapy. The identification of estrogen receptor target genes may improve our understanding of the role played by estrogens in breast cancer making it possible to better tailor hormone treatments and improve a patient's response to hormonal therapy. In this review, we explore the literature for data regarding the identification of estrogen receptor-regulated genes in breast cancer cell lines and breast tumor biopsies using high throughput technologies such as serial analysis of gene expression (SAGE) and cDNA microarrays.

Since the antibiotic properties of penicillin were first noticed in the beginning of last century, beta-lactam based antibiotics have been well developed as miracle drugs for the therapy of bacterial infectious diseases in clinics. Recently, these “old” antibiotics and their relevant derivatives have also found new applications as gene reporters, anti-cancer prodrugs and enzyme inhibitors. In this review, we will introduce the latest developments in the study of these new applications based on literatures reported over the last decade. The first section covers the recent developments of β-lactam antibiotics as drugs against bacteria, the second section briefly discusses the occurrence of bacterial resistance and mechanistic studies of β-lactam resistance in bacteria, the third section presents the current development of fluorogenic cephalosporin based β-lactam probes for real-time imaging of gene expression, and the fourth section describes relevant studies on β-lactam based substrates as anti-tumor prodrugs. Beta-lactam substrates as protease inhibitors will be also described in the fifth section. The final section summarizes future perspectives for β-lactam antibiotic derivatives as scaffolds in the fields of molecular imaging, drug delivery and enzymatic assays.

Systemic inflammatory response can be associated with clinically significant and, at times, refractory hypotension. Despite the lack of uniform definitions, this condition is frequently called vasoplegia or vasoplegic syndrome (VS), and is thought to be due to dysregulation of endothelial homeostasis and subsequent endothelial dysfunction secondary to direct and indirect effects of multiple inflammatory mediators. Vasoplegia has been observed in all age groups and in various clinical settings, such as anaphylaxis (including protamine reaction), sepsis, hemorrhagic shock, hemodialysis, and cardiac surgery. Among mechanisms thought to be contributory to VS, the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway appears to play a prominent role. In search of effective treatment for vasoplegia, methylene blue (MB), an inhibitor of nitric oxide synthase (NOS) and guanylate cyclase (GC), has been found to improve the refractory hypotension associated with endothelial dysfunction of VS. There is evidence that MB may indeed be effective in improving systemic hemodynamics in the setting of vasoplegia, with reportedly few side effects. This review describes the current state of clinical and experimental knowledge relating to MB use in the setting of VS, highlighting the potential risks and benefits of therapeutic MB administration in refractory hypotensive states.

Induction of apoptosis and pro-inflammatory cytokine gene expression in influenza virus-infected cells activates production of toxic superoxide by macrophages. Pyrrolidine dithiocarbamate and nordihydroguaiaretic acid inhibit influenza virus proliferation and scavenge superoxide. These results suggest that they can be potential candidates for a drug of choice for influenza chemotherapy.

We review the role of E-cadherin in cancer progression, and its therapeutic restoration as a strategy to suppress metastasis. We subsequently discuss E-cadherin upregulating drugs, proposing a schema for restoring E-cadherin by targeting its epigenetic and transcriptional regulators. These pathways will likely provide significant future treatment breakthroughs against cancer metastasis.

Endogenous reactive intermediates including photoexcited states of tissue chromophores, reactive oxygen species (ROS), reactive carbonyl species (RCS), transition metal ions, and Schiff bases have been implicated in the initiation and progression of diverse human pathologies including tumorigenesis, atherosclerosis, diabetes, and neurodegenerative disease. In contrast to structure-based approaches that target macromolecules by selective ligands, reactivity-based drug discovery uses chemical reagents as therapeutics that target reactive chemical species involved in human pathology. Reactivity- based design of prototype agents that effectively antagonize, modulate, and potentially even reverse the chemistry underlying tissue damage from oxidative and carbonyl stress therefore holds great promise in delivering significant therapeutic benefit. Apart from its established role as an essential cofactor for numerous enzymes, a large body of evidence suggests that B6-vitamers contain reactive pharmacophores that mediate therapeutically useful non-vitamin drug actions as potent antioxidants, metal chelators, carbonyl scavengers, Schiff base forming agents, and photosensitizers. Based on the fascinating chemical versatility of B6-derived pharmacophores, B6-vitamers are therefore promising lead compounds for reactivity-based drug design.

Chemoprevention is presumably one of most effective means to combat prostate cancer (PCa). Patients usually require more than a decade to develop a clinically significant Pca, therefore, an ideal target for chemoprevention. This review will focus on recent findings of a group of naturally occurring chemicals, carotenoids, for potential use in reducing PCa risk.