Current Medicinal Chemistry (v.17, #35)

Recent Advances in the Development of Dual Topoisomerase I and II Inhibitors as Anticancer Drugs by S. Salerno, F. Da Settimo, S. Taliani, F. Simorini, C. La Motta, G. Fornaciari, A. M. Marini (4270-4290).
DNA topoisomerases (topos) are essential enzymes that regulate the topological state of DNA during cellular processes such as replication, transcription, recombination, and chromatin remodeling. Topoisomerase I (Topo I) is a ubiquitous nuclear enzyme which catalyzes the relaxation of superhelical DNA generating a transient single strand nick in the duplex, through cycles of cleavage and religation. Topoisomerase II (Topo II) mediates the ATP-dependent induction of coordinated nicks in both strands of the DNA duplex, followed by crossing of another double strand DNA through the transiently broken duplex. Although the biological functions of Topoisomerases are important for ensuing genomic integrity, the ability to interfere with enzymes or generate enzyme-mediated damage is an effective strategy for cancer therapy and, in this connection, DNA topos (I and II) proved to be the excellent targets of clinically significant classes of anticancer drugs. Actually, specific Topo I and Topo II inhibitors reversibly trap the enzyme-DNA complexes, thus converting topos into physiological poisons, able to produce permanent DNA damage, which triggers cell death. Given that both enzymes are good targets, it would be desirable to jointly inhibit them, but use-limiting toxicity of sequential or simultaneous combinations of Topo I and II poisons include severe to life-threatening neutropenia and anemia. Furthermore, the emergence of resistance phenomena to Topo I inhibitors is often accompanied by a concomitant rise in the level of Topo II expression and viceversa, leading to the failure of clinical therapies. In this regard, a single compound able to inhibit both Topo I and II may present the advantage of improving antitopoisomerase activity, with reduced toxic side effects, with respect to the combination of two inhibitors. Due to the high interest in such compounds, this review represents an update of previous works dealing with the development of dual Topo I and II inhibitors as novel anti-cancer agents. The newly collected derivatives have been described focusing attention on their chemical structures and their biological profiles.

Novel Agents in the Management of Lung Cancer by B. Kennedy, F. Gargoum, B. Bystricky, D. R. Curran, T. M. O'Connor (4291-4325).
Lung cancer is the leading cause of cancer death worldwide. Survival remains poor as approximately 80and#x25; of cases present with advanced stage disease. However, new treatments are emerging which offer hope to patients with advanced disease. Insights into cell biology have identified numerous intracellular and extracellular peptides that are pivotal in cancer cell signalling. Disrupting the function of these peptides inhibits intracellular signal transduction and diminishes uncontrolled proliferation, resistance to apoptosis and tumour angiogenesis. The most widely studied signalling pathway is the Epidermal Growth Factor (EGF) pathway. EGF signalling can be disrupted at numerous points. Blockade of the cell surface receptor is achieved by the monoclonal antibody cetuximab; intracellular tyrosine kinase activity is inhibited by erlotinib. Vascular Endothelial Growth Factor (VEGF) regulates another pathway important for tumour growth. Inhibition of VEGF impairs angiogenesis and disrupts metastatic spread. Bevacizumab is a monoclonal antibody that binds to VEGF and blocks interaction with its cell surface receptor. Clinical trials have demonstrated that disruption of these signalling pathways can improve survival in advanced lung cancer. New compounds including folate antimetabolites such as pemetrexed, proteasome inhibitors such as bortezomib, modified glutathione analogues such as TLK286, and other agents such as epothilones and other small molecules are currently being evaluated in patients with lung cancer. As more and more signalling peptides are targeted for manipulation, it is hoped that a new era is dawning in the treatment of advanced stage lung cancer. This review will focus on emerging new therapies in the management of lung cancer.

The phosphoinositide 3-kinase (PI3K)/serine-theronine protein kinase Akt (also known as protein kinase B (PKB))/mammalian target of rapamycin (mTOR) pathway is a vital transduction cascade that is connected with many essential cellular activities, such as growth and survival. Along with extensive pharmacological studies validating the therapeutic potential of targeting the PI3K/Akt/mTOR pathway for the treatment of cancer, kinase inhibitors targeting significant knots of this pathway including PI3K, Akt, mTOR, and 3-phosphoinositide-dependent protein kinase-1 (PDK-1) keep arising and entering clinical studies. Herein, we review the most up-to-date landscape on developing small-molecule kinase inhibitors targeting the PI3K/Akt/mTOR pathway, with emphasis on small-molecule inhibitors which have been progressed into clinical studies.

and#946;-Aryl-and#946;-amino acids constitute very useful scaffolds able to lead, via various intra-molecular cyclisation reactions, to a great diversity of cyclic derivatives with numerous biological and therapeutic properties. The present article aims at reporting an exhaustive overview of these ring-closure sequences and their application in the medicinal chemistry field.

UPA and PAI-1 Analysis from Fixed Tissues - New Perspectives for a Known Set of Predictive Markers by K. Malinowsky, C. Bollner, S. Hipp, D. Berg, M. Schmitt, K. F. Becker (4370-4377).
The urokinase-type plasminogen activator (uPA) and its main inhibitor PAI-1 play key roles in tumorassociated processes such as the degradation of the extracellular matrix (ECM), tissue remodeling, cell adhesion and migration. Elevated expression of both molecules is known to correlate with negative outcomes in node negative breast cancer. To date, these molecules are the only prognostic markers to have reached the highest level of evidence (LOE I) in multi-centered clinical trials for prognosis of node negative breast cancer. Unfortunately, the clinical utility of these molecules as markers is limited by the use of enzyme-linked immunoassay (ELISA) tests for their detection. The ELISA relies on the use of fresh or frozen tissue, which are rarely available in routine clinical settings. In this review article, we provide an overview of the clinical relevance of uPA and PAI-1 and present alternative methods for their detection. Common uPA and PAI-1 detection methods discussed in literature include RT-PCR-based assays and classical immunohistochemistry approaches. In recent years, attempts have been made to isolate and analyze proteins of formalin fixed, paraffin embedded (FFPE) tissues. These new methods are of special interest because up to now neither RT-PCR nor immunohistochemistry are recommended for the detection of uPA and PAI-1. Here, we present an approach for the analysis of uPA and PAI-1 directly from FFPE tissues that may eventually overcome the limitations of current assays and make the use of both markers widely available for routine prognosis and therapy decisions for breast cancer patients.

Parkinson's disease (PD), a common neurodegenerative disease, is characterized by the progressive loss of dopamine neurons and the accumulation of Lewy bodies and neurites. The exact role of genetic and environmental factors in the pathogenesis of PD has frequently been debated. The association of MPTP (methyl-4-phenyl-1, 2, 3, 6- tetrahydropyridine) and toxins (such as rotenone) with parkinsonism highlights the potential etiologic role of environmental toxins in disease causation. The recent discoveries of monogenic (such as and#945;-synuclein, Parkin, UCHL1, PINK1, DJ-1, LRRK2) forms of PD have provided considerable insights into its pathophysiology. Parkin, an ubiquitin protein ligase assists in the degradation of toxic substrates via the ubiquitin proteasome system. It can also mediate a nondegradative form of ubiquitination. PINK1 and LRRK2 are possibly involved in the phosphorylation of substrates important for various cellular functions. Some toxins could interact with and#945;-synuclein, an endogenous protein that is implicated in pathology of PD. Increasing in vitro and in vivo studies suggest that deficits in mitochondrial function, oxidative and nitrosative stress, the accumulation of aberrant or misfolded proteins, and ubiquitin-proteasome system dysfunction underpin the pathogenesis of sporadic and familial forms of PD. Elucidation of the functions of the proteins encoded by the diseasecausing genes will provide an opportunity for identification of specific pathways that could be targeted in neurotherapeutics.

Targeting Transcription Factor Activity as a Strategy to Inhibit Pro- Inflammatory Genes Involved in Cystic Fibrosis: Decoy Oligonucleotides and Low-Molecular Weight Compounds by G. Cabrini, V. Bezzerri, I. Mancini, E. Nicolis, M. C. Dechecchi, A. Tamanini, I. Lampronti, L. Piccagli, N. Bianchi, M. Borgatti, R. Gambari (4392-4404).
The development of drugs able to inhibit the expression of pro-inflammatory genes is of great interest in the treatment of cystic fibrosis (CF). Chronic pulmonary inflammation in the lungs of patients affected by CF is characterized by massive intra-bronchial infiltrates of neutrophils. This process is initiated upon interaction of pathogens (including Pseudomonas aeruginosa) with surface bronchial cells. Consequently, they release cytokines, the most represented being the potent neutrophilic chemokine Interleukin (IL)-8 and the pro-inflammatory cytokine IL-6. The chronic inflammatory process is crucial, since it leads to progressive tissue damage and severe respiratory insufficiency. In order to reduce the adverse effects of the excessive inflammatory response, one of the approaches leading to inhibition of IL-8 and IL-6 gene expression is the transcription factor (TF) decoy approach, based on intracellular delivery of double stranded oligodeoxynucleotides (ODNs) mimicking the binding sites of TFs and causing inhibition of binding of TFrelated proteins to regulatory sequences identified in the promoters of specific genes. Since the promoters of IL-8 and IL-6 contain consensus sequences for NF-and#954;B and Sp1, double stranded TF and#x201C;decoyand#x201D; ODNs targeting NF-and#954;B and Sp1 can be used. Alternatively, screening of drugs targeting relevant TFs can be performed using drug cocktails constituted by extracts from medicinal plants inhibiting TF/DNA interactions. Finally, virtual screening might lead to identification of putative bioactive molecules to be validated using molecular and cellular approaches. By these means, low-molecular drugs targeting NF-and#954;B and inhibiting IL-8 gene expression are available for pre-clinical testing using experimental systems recapitulating chronic pulmonary inflammation of patients affected by CF.

Pharmacology and Chemistry of Diabetes mellitus and Antidiabetic Drugs: A Critical Review by Ganesh R. Kokil, Prarthana V. Rewatkar, Arunima Verma, Suresh Thareja, Suresh R. Naik (4405-4423).
Diabetes mellitus, an epidemic metabolic disorders characterized by high blood glucose level associated with various macrovascular and microvascular complications, is one of the main causes of human suffering across the globe. Researchers around the world mainly focused on insulin, insulin analogues, oral hypoglycemic agents and various other complementary and alternate medicines to control the blood glucose levels in diabetes. The present review summarizes the disorders associated with elevation of blood glucose level, biochemical and endocrinological aspects and the current strategies to control. The emphasis has been laid in particular on the new potential biological targets and the possible treatment as well as the current ongoing research status on new generation hypoglycemic agents.

Micro-Determination of Iron in Pharmaceutical Preparations by Image Scanning and Computational Quantification by J. Anwar, M. Salman, U. Shafique, Waheed-uz-Zaman, A. Dar, J. M. Anzano (4424-4426).
Iron has been quantified in pharmaceutical preparations by developing red spots pursuant to interaction of Fe(II) ions in the sample with 1, 10-phenanthroline on TLC plate. Soon after, TLC was scanned on a flatbed scanner and the image was transferred to the computer. Color intensity of the spot was computationally quantified with the help of native software developed for this purpose. The conditions were optimized and the results were compared with a reference method.