Current Medicinal Chemistry - Volume 17, Issue 10, 2010

Fulvestrant is a novel endocrine therapy for breast cancer, with a unique structure and mode of action. It binds competitively to the oestrogen receptor (ER), with high affinity, and downregulates ER by functional blockade and increased turnover. Fulvestrant has reached the clinic via extensive pre-clinical and clinical trials, which demonstrated fulvestrant's unique characteristics and showed that they translate to equivalent or improved clinical efficacy compared to established endocrine agents. Fulvestrant is currently licensed for use in postmenopausal women with hormone receptor positive advanced breast cancer which has progressed on prior endocrine therapy. As a pure oestrogen antagonist, fulvestrant avoids the risk of detrimental side effects of selective ER modulators such as tamoxifen, which has partial agonist activity. Fulvestrant, the only parenteral agent in this setting, has a good side effect profile and is well tolerated. Due to its unique mode of action, fulvestrant lacks cross-resistance with existing agents. Fulvestrant is the subject of much ongoing research, which utilises knowledge of its novel mechanism and pharmacokinetic profile in order to optimise clinical efficacy and explore new roles, including first-line use in advanced breast cancer, use in combination with existing agents, in males, and in premenopausal women, and use as an adjuvant therapy.

2,3-dihydrobenzo[b][1,4]oxathiine represents a valuable pharmacophoric heterocyclic nucleus known since very long time. Initially, together with some patents reporting the use of these compounds as herbicides or lipogenesis inhibitors, several papers reported their ability as melatonin, histamine and serotonin receptor ligands, α-adrenoreceptor blockers as well as non-glycoside sweeteners. This wide range of biological activities has been recently further improved by studies stating their activity as antimycotics, multi-defense antioxidants and estrogen receptor ligands. The last insights regarding the preparation, the biological activity and the structure activity relationship (SAR) of derivatives containing the dihydrobenzoxathiine skeleton will be discussed in this review.

Malaria is a major worldwide public health threat with worrying social and economic burdens due to the rapid emergence of multidrug-resistant Plasmodium falciparum strains. As a result, there is an urgent need to find novel drugs that might overcome clinical resistance to marketed antimalarials. In recent years, the mitochondrial electron transport chain (mtETC) has been explored for the development of new antimalarials. Type II NADH:quinone oxidoreductase (PfNDH2), succinate dehydrogenase (SDH) and cytochrome bc1 have become a major focus of those efforts, leading to several studies of its biochemistry and the design of potent inhibitors. Furthermore, de novo pyrimidine biosynthesis in malaria parasites, particularly dihydroorotate dehydrogenase (PfDHODH), is also receiving increasing attention. The enzymes involved in the mtETC are valuable targets in malaria chemotherapy, not only because they play a critical role in metabolic pathways of P. falciparum, but also because they differ significantly from the analogous mammalian system. Inhibition of such enzymes results in the shutdown of mitochondrial electron flow, leading to the arrest of pyrimidine biosynthesis and consequent parasite death. In this review, we aim to outline recent advances in the inhibition of mitochondrial metabolic pathways, highlighting the major classes of known inhibitors and those that are currently being developed.

The highly conserved heat-shock proteins (HSPs) from mammals and microbial reagents are among the immunogenic proteins. Their expression is induced in response to a wide variety of physiological and environmental insults. Their functions as molecular chaperones allow cells to adapt to gradual changes in their environment and to survive in otherwise lethal conditions. Although the role of HSPs in atherosclerosis remains controversial, HSPs were thought to act as autoantigens, and trigger both cell- and antibody-mediated immune responses. However, HSPs possess immunoregulatory attributes as well and therefore, are being exploited for immunomodulation of atherosclerosis either by the adaptive or innate immune system. This review will focus on a number of HSPs from different families including HSPE, HSPB, DNAJ, HSPD, HSPA, HSPC and HSPH. The role of these HSPs, their protective vs. immunogenic properties with special emphasis on their potential as targets to develop therapeutic agent against atherosclerosis will be discussed.

Acute kidney injury (AKI) is a syndrome characterized by an acute renal cell injury that leads to sudden loss of renal function. There are currently no clinically validated treatments for AKI besides substituting renal function by dialysis. However, new biomarkers will allow an earlier diagnosis, thus providing a window of opportunity for therapeutic intervention. Acute kidney injury (AKI) is a syndrome characterized by an acute renal cell injury that leads to sudden loss of renal function. There are currently no clinically validated treatments for AKI besides substituting renal function by dialysis. However, new biomarkers will allow an earlier diagnosis, thus providing a window of opportunity for therapeutic intervention. We review the potential role of tyrphostins in the prophylaxis and treatment of acute kidney injury on the basis of published studies on animals, in vitro experiments and piecemeal information from humans. The AG 490 and AG 126 tyrphostins have recently been shown to protect from AKI in experimental animal models of ischemia-reperfusion and sepsis-induced injury. AG 490 protects from cyclosporin-induced AKI and AG 1714 protects from cisplatin nephrotoxicity. AG 490 is nephroprotective by inhibiting oxidative stress-related Janus activated kinase-2 (JAK2) activation. Potential applications of AG490 or derivative molecules include AKI of nephrotoxic or ischemic nature, or a combination of both, as may occur in the immediate postransplant period. The molecular targets of AG 126 and AG 1714 are less well characterized. In conclusions, different tyrphostins are nephroprotective in animal models of AKI. The characterization of the molecular targets involved will allow the design of novel therapies that may reach the clinical trial stage.

The study of neuroscience has vastly benefited from the use of brain slices. This preparation has been fundamental for the understanding of the cellular basis of nervous system function as well as for the study of the mechanisms involved in neuronal network dysfunction. This experimental model provides flexible access, and control of, specific neural circuits and maintains their basic properties, allowing them to reproduce most of their natural network activities. Brain slices permit the combination of sophisticated techniques such as electrophysiology, fluorescence imaging, pharmacology, molecular biology, etc. More recently, the development of organotypic brain slice cultures has expanded the use of modern technical approaches to the study neuronal networks, while increasing their possibilities of evaluating long-term effects of acute experimental conditions, as well as the effects of chronic treatments on neuronal network function in vitro. Here, I will provide an overview of the use of organotypic cultures to understand neuronal network function and dysfunction, as well as the pharmacological approaches used for these studies. As a final example, I will review the studies performed in organotypic cultures regarding the deleterious effects of long-term amyloid beta application on neuronal networks in vitro, as well as the use of drugs that may prevent or revert their deleterious effects on nervous system function. Overall, this review will provide elements to support the use of organotypic cultures as a very reliable model to explore long-term neuropharmacological studies in vitro.

In the last decade, there has been enormous progress in our understanding of Frontotemporal Lobar Degeneration (FTLD). Published clinicopathological series have clearly demonstrated an overlap between the clinical syndromes subsumed under the term frontotemporal dementia and the Progressive Supranuclear Palsy (PSP), and the Corticobasal Degeneration (CBD) syndrome. From a neuropathological point of view, two broad pathological subdivisions of FTLD are currently recognized: a) tau-positive pathology due to the accumulation of various forms of the microtubule-associated protein tau, that encompasses FTLD with Pick bodies, PSP and CBD, and b) tau-negative pathology, mainly characterised by ubiquitin/TDP-43-immunoreactive inclusions and in some cases due to Progranulin mutations. Several biological markers in cerebrospinal fluid and in blood have been evaluated to identify monogenic forms of FTLD and to differentiate either FTLD spectrum disorders or FTLD from other neurodegenerative disorders. The proposed biomarkers are primarily related to the mechanisms underlying the accumulation of the abnormal proteins in FTLD such as Tau, TDP-43 and Progranulin. These biomarkers may support the accurate diagnosis of the specific diseases causing FTLD, can be useful in assessing efficacy during pharmacological trials, and may help in identifying new molecular targets for treatment approaches. In this review, we summarise the most recent findings on biological markers and their usefulness in clinical practice for the diagnosis and management of FTLD.