Current Medicinal Chemistry - Volume 22, Issue 9, 2015

The amyloid-β peptide (Aβ) has been associated with Alzheimer’s disease (AD) for decades. The original amyloid cascade hypothesis declared that the insoluble extracellular plaques were responsible for Aβ toxicity. Later, this hypothesis has been updated and soluble intracellular Aβ forms and their effects within the cell have come into focus. Mitochondrial dysfunction plays an important role in the pathophysiology of AD. Aβ was detected inside mitochondria and several mitochondrial proteins were found to interact directly with Aβ. Such interactions can affect a protein’s function and cause damage to the mitochondria and finally to the whole cell. This review summarizes the current knowledge of mitochondrial proteins directly interacting with Aβ and discusses their significance for the development of therapeutics in the treatment of AD.

The pharmaceutical industry is struggling with a lack of potential drugs in the pipe line. However, there is still a great opportunity to elaborate interesting scaffolds for medicinal chemistry. Various scaffolds that hold promise are not (or little) studied or are not (or only a few times) described in literature. For the last couple of decades, a wide range of biological activities of benzodiazepine derivatives have been investigated thoroughly and have made the benzodiazepine scaffold, particularly the 1,4-benzodiazepine system, one of the most important structures for drug discovery. The substantial research on benzodiazepines has led to the synthesis of heterocycle-fused azepine derivatives with potentially new pharmacological activity. Some pyridoazepines are known to be active in the central nervous system and have a comparable activity to the well-known benzodiazepine scaffolds, which make the synthesis and the study of pyridoazepines an important research topic.

Endogenous glucocorticoids exert a diverse array of physiological processes including immunemodulatory or anti-inflammatory responses and play an important role in the pathogenesis of inflammatory and autoimmune diseases. Regulation of inflammatory processes by glucocorticoids is controlled in a cytokinehypothalamo- pituitary-adrenal axis feedback circuit and on the local, cell-type and context-specific local regulatory system. At the tissue level the sensitivity and response to glucocorticoids are determined by multiple factors: including the local availability to glucocorticoids transported by blood, the locally-formed bioactive glucocorticoids (synthesized and metabolized 11β-hydroxysteroid dehydrogenase enzymes), the number and function of the glucocorticoid receptor (GR) and the GR affinity to its ligands. Numerous molecular factors are known to influence the sensitivity of glucocorticoid response through the GR. Cytokines are one of the major components that can inhibit GR function and can potentiate the resistance against glucocorticoids. GR isoforms, generated by alternative splicing, alternative translation and posttranslation modification are further mechanisms which modulate glucocorticoid signaling. Genetic variants within the GR encoding gene are other potential factors that may influence the susceptibility and severity of autoimmune disorders and may play a key role in individual response to medication. In this review our aim was to summarize our knowledge about the connections between the cell type-specific glucocorticoid signaling and the local immune system. Prediction of individual sensitivity to steroids and identification of key players in development of glucocorticoid resistance are essential in individualized therapies. The local, tissue-specific glucocorticoid signaling and its influence by cytokines may be important in determining the magnitude of inflammatory reactions, and may also be related to the success of glucocorticoidcontaining therapeutic strategies.

Survivin, a member of the inhibitor of apoptosis proteins family, is highly expressed in most human neoplasms, but its expression is very low or undetectable in terminally differentiated normal tissues. Survivin has been shown to inhibit cancer cell apoptosis and promote cell proliferation. The overexpression of survivin closely correlates with tumor progression and drug resistance. Because of its key role in tumor formation and maintenance, survivin is considered as an ideal target for anticancer treatment. However, the development of small-molecule survivin inhibitors has been challenging due to the requirement to disrupt the protein-protein interactions. Currently only a limited number of survivin inhibitors have been developed in recent years, and most of these inhibitors reduce survivin levels by interacting with other biomolecules instead of directly interacting with survivin protein. Despite these challenges, developing potent and selective small-molecule survivin inhibitors will be important both in basic science to better understand survivin biology and in translational research to develop potentially more effective, broad-spectrum anticancer agents. In this review, the functions of survivin and its role in cancer are summarized. Recent developments, challenges, and future direction of small-molecule survivin inhibitors are also discussed in detail.

A large amount of pesticides are being used now-a-days in crop protection which has resulted in buildup of such harmful compounds in the environment, proving a menace to humans, animal life as well as to soil microbes. Residues of these pesticides have been reported in soil, water and foods. Carbendazim and sulfosulfuron are among the most widely used pesticides for treating fungal diseases and unwanted herbs in crops respectively. Carbendazim is a benzimidazole fungicide which can harm liver as well as the endocrine system and is suspected to have mutagenic and tumorigenic effects. On similar lines sulfosulfuron, a sulfonylurea herbicide may result in the development of resistant herbs displaying its carry-over effects to the next crop cultivated. These pesticides possess large half-lives and thus remain persistent in the environment which may lead to harmful consequences in the near future. Besides chemical and photo-catalytic degradation of pesticides, microbial degradation has now been evolved as a much effective and safer way to eradicate these harmful compounds from the environment. However a limited literature is available on the microbial degradation of such compounds. The present review emphasizes mainly upon the chemical properties of Carbendazim and Sulfosulfuron, detection of their residues, harmful effects and insights into their degradation studies. Further, the use of efficient microbes for remediation of pesticides from the environment has been discussed.

The prostate adenocarcinoma is the cancer with the highest incidence for men in Western countries. Targeting the androgen receptor (AR) by antagonists is used as hormone therapy for prostate cancer (PCa), however, eventually therapy resistance occurs in most patients. In most of these cancer the AR signaling is active and thus AR remains an important drug target. Since many years we are characterizing novel chemical structural platforms to provide a broader possibility for compounds that bind to and act as AR antagonists. Here, we describe the chemical synthesis of a battery of novel steroidal derivatives as nor-homo-, spiro-oxolan- and spiro-oxetan- steroids. They modulate the transcriptional activity of the human AR. As AR antagonists, the spiro-oxetan- steroid derivatives seem to be the most potent steroid derivatives. They inhibit the transcriptional activity of both wild-type AR as well as the AR mutant T877A. In line with this, these compounds bind to the human AR and inhibit the proliferation of the human androgen-dependent growing PCa cell line LNCaP. Interestingly, the castration-resistant AR expressing human PC3-AR cells are also growth inhibited. On mechanistic level, fluorescence resonance energy transfer (FRET) assays with living cells indicate that the androgeninduced N/C terminal interaction of the AR is inhibited by the investigated compounds. Using fluorescence recovery after photobleaching (FRAP) assays in living cells suggest a higher mobility of the AR in the cell nuclei in the presence of spiro-oxetan- steroidal antagonists. Together, these findings suggest that spiro-oxetan- steroids are very useful as a chemical platform for novel AR antagonists.