Current Medicinal Chemistry - Volume 15, Issue 6, 2008

Breast cancer is a common cause of tumors in women. The development of effective adjuvant therapies using drugs such as anthracyclines, taxanes, and aromatase inhibitors has improved the survival of breast cancer patients. Molecular cancer therapeutics are also attracting attention, and targeted molecular therapies, such as trastuzumab, have already contributed to effective new treatments for breast cancer. Other candidate targeted molecular therapies for breast cancer, including erlotinib, gefitinib, lapatinib, bevacizumab, and celecoxib, are currently undergoing clinical evaluation, and promising results are expected. The current review provides an up-to-date summary of the preclinical and clinical development of these drugs for breast cancer. In particular, we focus on therapies targeting protein kinase C (PKC) signaling, the putative metastasis-suppressor gene Cap43/N-myc downstream-regulated gene 1 (NDRG1)/differentiation-related gene-1 (Drg-1), and the Y-box binding protein-1 (YB-1). The PKC signaling pathway is widely considered to be a promising target for the development of novel therapeutics. Cap43 expression is significantly modulated by estrogen and/or anti-estrogens in breast cancer cells that are positive for estrogen receptor-α (ER-α). Cap43 is therefore of particular interest as a molecular indicator of the therapeutic efficacy of anti-estrogenic agents in breast cancer. The nuclear expression of YB-1 plays an essential role in the acquisition of malignant characteristics by breast cancer cells, through epidermal growth factor receptor 2 (HER2)-Akt-dependent pathways. Basic research investigating the key selective molecular changes that sustain breast cancer growth and progression, as demonstrated for PKC, Cap43, and YB-1, is allowing the development of specific targeted molecular diagnostics and therapeutics.

Neurodegenerative diseases do affect glial or neuronal cells in both the peripheral and central nervous systems. Although they are characterized by different features and a different onset, all the neurodegenerative diseases share the final steps that lead to cell death by apoptosis. Apoptosis occurs also during developmental neurogenesis. Neuron survival and differentiation depend on specific neurotrophic factors released by their targets. During degenerative diseases the loss of neuronal or glial cells is responsible for the disease's progression. Current therapies are focused on counteracting the degenerative events by acting on the molecular mechanisms involved in cellular death, or by the exogenous administration of pro-survival factors. The presence in many areas of both the peripheral and central nervous systems of niches of neural progenitors which can differentiate, under specific conditions, into neurons or glial cells opens up new therapeutic perspectives. The Mitogen-Activated Protein Kinase (MAPK) family, that includes ERK1/2, JNK/SAPK, p38 and ERK5, is involved in the survival, proliferation and differentiation of nervous cells. Some of the MAPKs promote the differentiation towards the neuron lineage, others towards the glial one. The MAPKs are also involved in apoptosis and may, therefore, play a role in neurodegeneration. This dual role of MAPKs may make it possible to design alternative and/or synergistic approaches to the treatment of degenerative diseases, either by using specific inhibitors of the MAPKs involved in apoptosis, or by increasing the activation of the MAPKs involved in neuronal survival and differentiation. The increased activation of pro-differentiative MAPKs can lead to the replacement of damaged neurons by undifferentiated progenitors and the slowing down of the disease's progression.

The adaptor protein 3BP2 (c-Abl Src homology 3 domain-binding protein-2, also referred to SH3BP2) is known to play a regulatory role in signaling from immunoreceptors. In mast cells, 3BP2 is rapidly tyrosine phosphorylated by the aggregation of the high affinity IgE receptor and the overexpression of its SH2 domain results in the dramatic suppression of IgE-mediated tyrosine phosphorylation of PLC-γ, Ca2+ mobilization and degranulation. 3BP2 is a substrate of the protein-tyrosine kinase Syk, which phosphorylates it on Tyr174, Tyr183, and Tyr446 (in the mouse protein). Phosphorylation of Tyr183 promotes the activation of Rac1 through the interaction with the SH2 domain of Vav1. Phosphorylation of Tyr446 induces the binding to the SH2 domain of the upstream protein-tyrosine kinase Lyn and enhances its kinase activity. Thus, 3BP2 has a positive regulatory role in IgE-mediated mast cell activation. In lymphocytes, engagement of T cell or B cell receptors triggers tyrosine phosphorylation of 3BP2. Suppression of the 3BP2 expression by siRNA results in the inhibition of T cell or B cell receptor-mediated activation of NFAT. Genetic analyses reveal that 3BP2 is required for the proliferation of B cells and B cell receptor signaling. Point mutations of the 3BP2 gene cause the rare human inherited disorder cherubism, characterized by excessive bone resorption in the jaw bones. These mutations include substitution and deletion mutations of 3BP2. “Cherubism” mice exhibit increased myeloid cell responses to M-CSF and RANKL leading to the activation of osteoclasts. Further analysis could demonstrate that inhibition of 3BP2 might have therapeutic potential.

Proteomics has unraveled important questions in the biology of cardiovascular disease and holds even greater promise for the development of novel diagnostic and prognostic biomarkers. This approach may establish early detection strategies, and monitor responses to therapies. Technological advances (most notably blue native polyacrylamide gel electrophoresis, electrospray ionization, matrix- assisted laser desorption/ionization (MALDI), analysis of MALDI-derived peptides in Time-of-Flight (TOF) analyzers, and multidimensional protein identification technology (MudPIT) and bioinformatics for data handling and interpretation allow a large-scale identification of peptide sequence and post-translational modifications. Moreover, combination of proteomic biomarkers with clinical phenotype, metabolite changes, and genetic haplotype information is promising for the physician assessment of individual cardiovascular risk profile.

Inhibition of Cdc25 phosphatases is a strategy for the discovery and development of novel anticancer agents targeting the cell cycle. A number of potent small molecule Cdc25 inhibitors have been identified. They are derived from different chemical classes; the most potent and selective derivatives are quinones. The electrophilic properties of quinones suggest the possibility of inducing a sulphydryl arylation of a cysteine in the enzyme active site. It is also possible that inhibition is due to redox cycling activity and production of ROS. Thus, oxidation of the thiolate form of cysteine occurs, leading to inactivation of enzymatic activity. Many of these inhibitors are active on all three Cdc25 phosphatases, cause cell cycle arrest and inhibit the growth of several human tumor cell lines. The possibility of toxicities induced by ROS, prompted the search for non-quinoid antagonists. It is not yet clear how these compounds bind within the enzyme's active site. Generally, electrophilic moieties able to trap the catalytic cysteine play an important role. Another strategy for identifying Cdc25 inhibitors is the development of compounds able to interact with the conserved loop region instead of phosphate. In this review a summary of the most interesting Cdc25 inhibitors is given together with their biological activity. SAR studies concerning the importance of some structural features will be described.

Despite great advancement in the understanding of the pathophysiology and in the development of novel therapeutic approaches, mortality of sepsis still remains unacceptably high. Adequate laboratory diagnostics represents a major requirement for the improvement of this situation. For a better understanding of the immunological dysregulation in this disease, several markers are now available for routine diagnostics in the clinical laboratory. They include the cytokines interleukin (IL) -6, IL-8, procalcitonin and the LPSbinding protein (LBP). These novel markers will be compared to the conventional procedure of diagnosing inflammatory and infectious disease, such as measurements of C-reactive protein (CRP) as a major acute phase protein and differential blood counting. Important questions addressed in this review are the usefulness of these markers for early diagnosis, their role as prognostic markers and in the risk assessment of patients. Furthermore, we will discuss whether these parameters are to differentiate between systemic inflammatory response syndrome (SIRS) and sepsis at its different degrees. In the case of an infectious nature of the disease, it is important to differentiate between viral or bacterial origin and to monitor the responsiveness of antibiotic therapies. The literature was analysed with focus on the evidence for diagnostic and analytical performance. For this purpose international definition and staging criteria were used in context of criteria for assay performance including sensitivity, specificity, negative and positive predictive values, ROC analysis and other analytical criteria.

Despite recent advances in supportive care, acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) are clinical entities with high morbidity and high mortality. In systemic inflammation, like sepsis, uncontrolled host defense can lead to systemic activation of coagulation on the one hand, and attenuation of fibrinolysis on the other. In ALI/ARDS similar but local disturbances in fibrin turnover occur, leading to excessive alveolar fibrin deposition compromising pulmonary integrity and function. Therapies in patients with sepsis have specifically focused on coagulation disturbances. Evidence from preclinical and clinical investigations suggests pharmacologically targeting pulmonary “coagulopathy” could be of benefit to patients with ALI/ARDS as well. Recent animal studies have demonstrated that administration of heparins, activated protein C (APC), Antithrombin (AT), Tissue factor- Factor VIIa (TF-FVIIa) pathway inhibitors, plasminogen activators (PA) and thrombomodulin (TM) can attenuate pulmonary coagulopathy and reduce lung injury and/or improve oxygenation. Some of these studies have also shown anti-inflammatory effects of treatment targeting at coagulation. To date there are no published studies that have specifically studied the effects of anticoagulants on ALI/ARDS however there are ongoing clinical trials. A solid base has to be provided by preclinical studies to justify clinical studies on new pharmacologic therapies for ALI/ARDS. In this systematic literature review we give an overview of the models for ALI/ARDS that have been used so far on the topic of pulmonary coagulopathy and focus on the pharmacological interventions that have been evaluated with these models. Finally, the applicability of the different approaches for future research on this subject will be discussed.

Perturbations in the redox-based network of cellular regulatory mechanisms have been associated with oxidative-related diseases such as diabetes mellitus. In these situations the redox state of cellular redox systems becomes persistently shifted toward oxidation that may result in a sequence of pathophysiological events. Innate and adaptive immune responses depend on the production of reactive oxygen species and ATP synthesis, which are tightly regulated by the mitochondrial transmembrane potential. Mitochondrial hyperpolarisation is a key mechanism of T-cell life, apoptosis and autoimmunity. The NADPH oxidase of the phagocytic cells of the immune system generates reactive oxygen metabolites during the respiratory burst, but activated B cells also possess NADPH oxidase and reactive oxidants could play regulatory roles in immune function. Cellular thiol levels and the thiol reduction-oxidation process modulate the oxidative metabolism in the cells, transcriptional factor activation of gene expression, lymphocyte proliferation and death. Flow cytometry allows directly characterising and analysing several parameters and functions of intact living cells in a few seconds. Fluorescent lipophilic cations have been used for the measurement of the mitochondrial transmembrane potential. Evaluation of reactive oxygen intermediates generation in neutrophils may be obtained by use of oxidation-sensitive probes. The dye resazurin has been used to quantify mitochondrial activity since considered to act as an intermediate electron acceptor in the electron transport chain between the final reduction of oxygen and cytochrome oxidase. The fluorescence emitted by 5-chloromethyl fluorescein acetate stained cells reflects the total level of free intracellular thiol. In this review we will discuss the possible importance and consequences of evaluating these redox parameters in diabetes pathophysiology. Moreover, we will provide perspectives concerning the varieties of analytical procedures that are capable of measuring them. The advantages and disadvantages of each of these methods are critically discussed particularly in view of their clinical application.

In 1980, Espey proposed a famous hypothesis that mammalian ovulation is comparable to an inflammatory reaction and many researches have proved the validity of his hypothesis in the last three decades. For example, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF) and other inflammatory cytokines presence was proven in the preovulatory follicle. Since granulocyte is the major leukocyte and it plays a very important role during inflammation, the importance of granulocyte and its related cytokine, granulocyte colony-stimulating factor (GCSF) in the mechanism of human ovulation is easily predictable. G-CSF is one of the hemopoietic cytokines and it has strong positive effects on granulocytes. G-CSF increases the number of granulocytes and it improves the function of granulocytes. In this review, the participation of leukocytes in the ovulation mechanism is demonstrated first. Second, the participation of G-CSF is shown in comparison with the above mentioned cytokines. Finally, since G-CSF has been used for more than 20 years as a medicine without severe side effects in the field of oncology, the clinical application of G-CSF for the treatment of an ovulation disorder, luteinized unruptured follicle (LUF), will be discussed.

Much of our understanding and knowledge of human parturition has been blurred by conjecture and extrapolation. The limited available data on human parturition reflect the inability to directly experiment with pregnant human subjects. In spite of this obvious impediment and the scarcity of longitudinal data on fundamental physiological changes in human pregnancy, recent reports have generated a better understanding of the synchronous activities leading to labor. The purpose of this review was to organize, in an evidence-based format, the current understanding of maternal physiologic phenomena leading from uterine quiescence to uterine labor activity. Recent discoveries have prompted a revision of pre-existing classical theories on the initiation of parturition, such as the progesterone block theory or the prostaglandins stimulation of the uterotonic action of oxytocin. The presence in the circulation of extrahypothalamic corticotrophin-releasing hormone (CRH) produced by the placenta and myometrium is an inciting unique feature of primate pregnancy and a promising field for research. The concept of anatomical regionalization in labor promotion, including the cervical physiological inflammatory reaction, is also discussed in the review, especially in support of the strong link between inflammatory activation and onset of preterm labor. Understanding the intimate chain of events leading to parturition is critical, and elucidating the interplay of signals and processes that initiate normal labor may help us to understand the abnormal variant, spontaneous preterm labor, and devise efficacious interventions against it.

The need for non-invasive assessment of airway inflammation is imperative, since inflammatory airway diseases, such as asthma and COPD, are characterized by variation in their clinical presentation throughout their course. Exhaled breath condensate (EBC) collection represents a rather appealing method that can be used to conveniently and noninvasively collect a wide range of volatile and non-volatile molecules from the respiratory tract, without affecting airway function or inflammation. Although promising, EBC is currently used only as a research tool, due to the lack of appropriate standardization and the absence of reference values. The large number of measurable biomarkers and the diversity of the used methodologies are some of the points that hamper its wide clinical application. This review focuses mainly on the presentation of normal values of the most widely studied EBC markers as reported by investigators that have used healthy subjects as controls or as a basic study population. These biomarkers include hydrogen peroxide, NO-related products, arachidonic acid metabolites and pH. From those biomarkers, the only one with established reference values in healthy subjects is EBC pH, whereas the majority of the rest need further refinement and standardization of the methodologies used. Different subpopulations and the effect of various factors on healthy subjects are also reported, in an effort to delineate future directions that may lead to the establishment of reference values.