Mini Reviews in Medicinal Chemistry - Volume 16, Issue 10, 2016

GLOBOCAN 2012 estimates 14.1 million new cancer cases and 8.2 million cancer-related deaths worldwide. Cancer is rapidly becoming a major public health concern in India as well, with the number of new cancer cases anticipated to double within the next 20 years. The percentage of currently approved metallodrugs is very low, in contrast to the majority of drugs available as organic compounds. The search for alternative drugs to cisplatin, carboplatin and other derivatives is highly needed due to their severe side effects including nephrotoxicity and neurotoxicity. Ruthenium, among other transition metal complexes appears to be a possible candidate for cancer therapy in the near future. The most significant rationale is ruthenium’s octahedral chemistry and greater propensity to undergo redox reactions. The hypoxic environment of tumors favors the reduction of inert ruthenium (III) to active ruthenium (II) which opens new prospects for the development of novel prodrugs. Although studies suggest that ruthenium complexes penetrate well within the tumor cells and bind effectively to DNA, its binding to proteins is not very well explained. Ruthenium complexes are presently receiving great attention in the fields of biological, pharmaceutical and medicinal chemistry as anticancer agents. This review poses a comprehensive overview of the studies on competent anticancer ruthenium complexes and the role of these metal complexes in relation to their anticancer properties as well as those under clinical trials.

The organometallic arene ruthenium complexes are rapidly advancing. In particular, the organoruthenium complexes of the type [(η6-arene)Ru(X)(Y)(Z)] have attracted increasing attention for their special structures and properties. This review is focused on the recent developments of [(η6- arene)Ru(X)(Y)(Z)]-typed complexes incorporating various biologically active ligands, which are important in the exploration of novel multi-targeted organometallic anticancer drugs.

Arene ruthenium(II) complexes have been widely investigated as one of the most promising candidates in chemotherapy because of their low toxicity and high inhibiting activity against the proliferation, invasion, migration, and angiogenesis of various tumors in vitro and in vivo. This review highlights the recent developments in different chemical types of arene Ru(II) complexes, as well as their biological activity and underlying mechanisms. The sustained efforts in this aspect of arene Ru(II) complexes would be essential in developing novel anti-tumor agents in the near future.

An overview of anticancer active (arene)ruthenium(II) complexes coordinated to period 2 element-based ligand systems, i.e., carbon-, nitrogen-, and oxygen-coordinated ligands, is provided in this mini-review. A bridge is forged from the large group of anticancer active ruthenium compounds with monodentate and chelating nitrogen ligands via complexes of O,O-chelating ligands to organometallic ruthenium derivatives coordinated to carbon. (Arene)ruthenium(II) complexes with reduced side-effects and enhanced efficacy against cancer are highlighted. Pertinent literature is covered up to 2014.

Increasing evidence highlights the role of the ATP synthase/hydrolase, also known as F1FO-complex, as key molecular and enzymatic switch between cell life and death, thus increasing the enzyme attractiveness as drug target in pharmacology. Being inhibition of ATP production usually linked to antiproliferative properties, drugs targeting the enzyme complex have been mainly considered to fight pathogen parasites and cancer. In recent years, a number of natural macrolides, produced by bacterial fermentation and structurally related to the classical enzyme inhibitor oligomycin, have been shown to bind to the membrane-embedded FO sector and to inhibit the enzyme complex by an oligomycin-like mechanism, namely by interacting with the c-ring. Other than natural macrolide antibiotics, which display variegated inhibition power on different F1FO-complexes, synthetic compounds from the diarylquinoline and organotin families also target the c-ring and strongly inhibit the enzyme. Bioinformatic insights address drug design to target FO subunits. Additionally, the possible modulation of the drug inhibition power, by amino acid substitutions or post-translational modifications of c-subunits, adds further interest to the target. The present survey on compounds targeting the c-ring and bi-directionally blocking the transmembrane proton flux which drives ATP synthesis/hydrolysis, discloses new therapeutic options to fight cancer and infections sustained by therapeutically recalcitrant microorganisms. Additionally, c-ring targeting compounds may constitute new tools to eradicate undesired biofilms and to address at the molecular level the therapy of mammalian diseases linked to mitochondrial dysfunctions. In summary, studies on the only partially known molecular interactions within the c-ring of the F1FO-complex may renew hope to counteract mammalian diseases.

Recently, there has been wide interest in compounds containing the oxadiazole scaffold because of their unique chemical structure and their broad spectrum of biological properties. This review provides readers with an overview of the main synthetic methodologies for oxadiazoles and of their broad spectrum of pharmacological activities such as, anti-microbial, anti-fungal activity, antiviral, anti-tubercular, anti-inflammatory, anti-convulsant, anti-angiogenic, anti-proliferative, analgesic, anti-oedema and in alzheimer activity, which were reported over the past years.

How to construct protein chips and chemically labeling drug molecules without disrupting structures for HTS is still a challenging area. There are two main obstacles, one is that human multitrans membrane receptors, which are major drug targets, exhibit distinct motifs, and fold structures, and they will collapse unfold without membrane support in vitro; another one is that there still lack effective chemical labeling method for small drugs for detection. Therefore, how to acquire high detecting sensitivity for small molecules and to immobilize membrane protein receptors in native conformation with uniform direction on the chip, need to be solved for drug HTS. This paper reviews drug HTS trends in recent years, proposed a new virion-chip model and a feasible C-H activation method for CY-5 labeling drugs. It is expected to provide a good platform for future drug HTS.