Current Drug Discovery Technologies - Volume 6, Issue 2, 2009

Spinal cord (SC) injury causes serious neurological alterations that importantly disturb the physical, emotional and economical stability of affected individuals. Damage to the neural tissue is primarily caused by the lesion itself and secondarily by a multitude of destructive mechanisms that develop afterwards. Unfortunately, the restoring capacity of the central nervous system is very limited because of reduced intrinsic growth capacity and non-permissive environment for axonal elongation. The regenerative processes are blocked by diverse factors such as growth inhibitory proteins and the glial scar formed in the site of lesion. In spite of these problems, central neurons regenerate if a permissive environment is provided. In line with this thought, some pharmacological compounds have been tested to achieve neuroregeneration. The main objective of this manuscript is to provide the state-of-art of chemotherapeutic treatments for spinal cord regeneration after injury in the field. The efficacy and usefulness of different therapeutic strategies will be reviewed, including Rho-ROCK inhibitors, cyclic AMPenhancers, glial scar inhibitors and immunophilin ligands. Aside from this, the use of hydrogels alone or in combination with drugs, growth factors or stem cells will also be revised.

Non small cell lung cancer (NSCLC) is a lethal disease with poor prognosis. The main percentage of NSCLC patients are diagnosed to have an advanced disease. Standard treatment, such as chemotherapy and radiotherapy, has apparently reached a plateau of effectiveness in improving survival of advanced NSCLC patients. Hence, considerable efforts have started to be made in order to identify novel targets for new biological agents which may safely and effectively be administered to advanced NSCLC patients. Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) and its receptors play an essential role in tumour proliferation. Approaches targeting EGFR and VEGF include monoclonal antibodies (mAbs) and small molecules inhibiting the corresponding receptor- tyrosine kinase activity. Erlotinib is a small molecule inhibitor of EGFR tyrosine-kinase which has brought significant improvements in median survival, quality of life and related symptoms, in an unselected population of advanced NSCLC patients in the second- or third-line setting. Bevacizumab, an anti-VEGF recombinant humanized mAb, is the first targeted agent which, when combined with chemotherapy, reported superior efficacy versus chemotherapy alone in the treatment of advanced NSCLC. ZD6474, a small molecule targeting VEGF tyrosine-kinase activity, showing early evidence of antitumour activity and the excellent toxicity profile, seems to be a promising agent for the treatment of advanced NSCLC. This review shows the latest and the future developments of erlotinib, bevacizumab and ZD6474 in the treatment of advanced NSCLC patients.

The last few years have seen a significant increase in our understanding of the molecular pathways governing cell function in cancer. This has led to an explosive interest in novel molecularly-targeted agents and, until recently, the focus of research effort has been to combine these agents with conventional cytotoxic chemotherapy. However, following a recent trial of an anti-EGFR targeted antibody in combination with radiation, a new paradigm is emerging in which these novel agents will be combined with external beam radiotherapy (RT). In this article we review classes of novel targeted radiosensitisers that are directed at specific aspects of cell function. Such agents are aimed at either single or multiple targets (the latter is a more attractive approach in view of cross-talk between different cell signaling pathways). We review available preclinical and clinical literature with a particular focus on novel agents targeting components of the ErbB and IGF-1R family cell signaling pathways. In this model, radiosensitisers can exert their effects at the cell membrane surface by preventing receptor activation or by interfering with the function of second messengers such as the Ras/PI3K/mTOR pathway. In addition, the effects of novel DNA repair inhibitors will be considered in the context of combination strategies with signal transduction pathway blockade. Other small molecule inhibitors, such as HSP90 inhibitors, that can disrupt signaling in a number of different pathways, will also be discussed. Ultimately, through the synergistic use of these innovative molecules and RT, the therapeutic index may be enhanced by modulating cellular metabolism, proliferation, repair, angiogenesis, and apoptosis. The rapid proliferation of available targeted agents and their entry into phase I clinical trials means that this is an extremely interesting area for research in radiation oncology.

The nature of plasma-induced surface radicals formed on a variety of organic polymers has been studied by electron spin resonance (ESR), making it possible to provide a sound basis for future experimental design of polymer surface processing using plasma treatment. On the basis of the findings from such studies, several novel bio-applications in the field of drug- and biomedical- engineering have been developed. Applications for drug engineering include the preparation of reservoir-type drug delivery system (DDS) of sustained- and delayed-release, and floating drug delivery system (FDDS) possessing gastric retention capabilities, followed by preparation of “Patient-Tailored DDS”. Furthermore, the preparation of composite powders applicable to matrix-type DDS was developed by making a mechanical application to the surface radical-containing polymer powders with drug powders. In applications for biomedical engineering, the novel method to introduce the durable surface hydrophilicity and lubricity on hydrophobic biomedical polymers was developed by plasma-assisted immobilization of carboxyl group-containing polymer on the polymer substrate. The surfaces thus prepared were further used for the covalent immobilization of oligo-nucleotides (DNA) onto the polymer surfaces applicable to constructing DNA diagnosis system, and also plasma-assisted preparation of functionalized chemo-embolic agent of vinyl alcohol-sodium acrylate copolymer (PVA- PAANa).

Calixarenes, macrocyclic compounds of phenolic units linked by methylene groups at the 2,6-positions, present some of the requirements to serve as platforms for the design and synthesis of biological active compounds. They are also interesting host molecules for chemical biology study purposes. Their basic molecular scaffold has potential ability for molecule recognition; it is promptly synthesized in large amounts, and might be easily modified for maximizing molecular interactions toward relevant guest molecules. Calixarenes present well-defined conformational properties and cavities with molecular dimensions that enable to encapsulate guest drugs. Calixarenes have been shown to have antiviral, antibacterial, antifungal, and anticancer activities (including HIV as target). We provide here an overview of the use of calixarenes either as new chemical entity of distinct biological activities or as host for bioactive guest molecules. The importance of calixarenes for drugs development is discussed. The use of Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) techniques for the study of calixarenes as biological molecule hosts is also described.