Current Medicinal Chemistry - Volume 24, Issue 12, 2017

Pre-clinical and clinical studies have investigated the role of a dysregulated metabolism in the sustainability of tumor initiation and progression. One of the most familiar metabolic alterations encountered in several types of cancers is the upregulation of glycolysis, which is also maintained in conditions of normal oxygen tension (aerobic glycolysis, Warburg effect) while oxidative phosphorylation is apparently reduced. As a result, cancer cells convert most incoming glucose to lactate. Although more rapid, adenosine triphosphate (ATP) production by glycolysis is less efficient in terms of ATP generated per unit of glucose consumed than oxidative phosphorylation. The consequence is that tumor cells require an abnormally higher rate of glucose compared to the normal counterpart. New evidence shows that other metabolic substrates such as glutamine may also have an important role in cancer metabolism. Ketogenic diet (KD) replaces all but non-starchy vegetable carbohydrates with low to moderate amounts of proteins and high amounts of monounsaturated and polyunsaturated fats. The rationale of KD is valid both because it lowers carbohydrate uptake possibly leading to cancer cell starvation and apoptosis and, at the same time, increases the levels of ketone bodies available for energy production in normal cells but not in cancer cells which have an allegedly downregulated oxidative phosphorylation. For this reason, several authors speculate on the possibility to evaluate KD as a novel approach in the treatment of cancer. In this review we will assess the data supporting the use of such alimentary regimen and its impact on tumor development and progression.

Cancer cells are permanently being selected for survival and proliferation. During this process, tumor cells often co-opt basic physiological mechanisms to protect themselves from toxic chemotherapy. One of these mechanisms is the overexpression of ATP-binding cassette (ABC) drug efflux pumps leading to multidrug resistance (MDR) of cancer cells through an increase of drug efflux. In the past 20 years, many efforts were done to circumvent MDR through the inhibition of ABC transporters. A number of inhibitors of these transporters were found but are rarely specific or rationally developed. Beside this approach, a new therapeutic strategy towards eradicating drug resistant tumor cells has recently emerged from the observation that cancer cells expressing a high level of these pumps show an unexpected hypersensitivity, called collateral sensitivity (CS) to a selected subset of chemical compounds. In this review, we target the multidrug resistance protein 1 (MRP1) and after a non-exhaustively highlighting of some of the most exemplary inhibitors of MRP1 and modulators of its expression, we focus on CS agents specifically targeting MRP1 which becomes, when overexpressed, the so called “ Achilles' heel” of multidrug resistant cancer cells. We discuss the link between the prominent role of glutathione translocation and related redox balance of the cell and the CS induced by certain types of compounds. The latter are discussed according to their chemical class, and perspectives in their development for successful eradication of resistant cancer are proposed.

In line with our previous studies, novel morpholine and benzoxa(or thia)zine lead compounds have been developed through a rational design that modulate a multiplicity of targets against atherosclerosis. We have evaluated the most promising compounds for their efficiency to a) intercept and scavenge free radicals, b) inhibit the metal ion (Cu2+)-induced LDL oxidation c) act intracellularly as antioxidants in THP-1 monocytes from a leukemic patient and d) inhibit the pro-inflammatory enzymes cyclooxygenase-1 (COX-1) and -2 (COX-2) in vitro. Furthermore, two representative compounds were tested for their potential to decrease lipidemic parameters (TC, LDL and TG) in hyperlipidemic mice. Most derivatives indicated a remarkable antioxidant activity, while at the same time exhibited a significant in vitro anti-inflammatory activity, inhibiting COX-1 or/and COX-2 activity at 20 μ. In addition, after their long-term administration, compounds 6 and 8 afforded considerable activity in a chronic experimental animal model of hyperlipidemia (after high fat diet administration). The multifunctional pharmacological profile exhibited by the compounds of this study renders them interesting lead compounds for the development of novel agents against atherosclerosis.

Fc-fusion proteins are composed of Fc region of IgG antibody (Hinge-CH2-CH3) and a desired linked protein. Fc region of Fc-fusion proteins can bind to neonatal Fc receptor (FcRn) thereby rescuing it from degradation. The first therapeutic Fc-fusion protein was introduced for the treatment of AIDS. The molecular designing is the first stage in production of Fc-fusion proteins. The amino acid residues in the Fc region and linked protein are very important in the bioactivity and affinity of the fusion proteins. Although, therapeutic monoclonal antibodies are the top selling biologics but the application of therapeutic Fc-fusion proteins in clinic is in progress and among these medications Etanercept is the most effective in therapy. At present, eleven Fc-fusion proteins have been approved by FDA. There are novel Fc-fusion proteins which are in pre-clinical and clinical development. In this article, we review the molecular and biological characteristics of Fc-fusion proteins and then further discuss the features of novel therapeutic Fc-fusion proteins.

Sphingolipids (SLs) regulate apoptosis, proliferation, and stress response. SLs, including ceramide, glycosphingolipids (glucosylceramide, lactosylceramide, and gangliosides) and sphingosine-1-phosphate (S1P), play a role in the pathogenesis and progression of genetic (lysosomal storage disease, congenital nephrotic syndrome and polycystic kidney disease) and non-genetic forms of chronic kidney diseases (CKDs). SLs metabolism defects promote complications (cardiovascular events, etc.) via oxidant stress in CKDs. A balancing role of apoptotic SLs and anti-apoptotic S1P is crucial in the regulation of glomerular injury and complications associated with CKDs. Interaction between SLs, endothelial function and reninangiotensin- aldosterone system (RAAS) plays an important role in the regulation of glomerular injury. SLs affect mitochondrial function that regulate the opening of mitochondrial permeability transition (MPT) pore, mitochondrial outer membrane permeability (MOMP), generation of reactive oxygen species (ROS), and expression of BcL-2 family proteins, which result in cytochrome c release and caspase activation, leading to apoptosis, and regulate glomerular cell proliferation or renal fibrosis. This review article summarizes the current evidence supporting a role of SLs metabolism defects in the pathogenesis and progression of glomerular injury and discusses a role of mitochondria, including MPT pore, MOMP, ROS generation, BcL-2 family proteins, interaction between SLs, endothelial function and RAAS, and SLs-induced downstream signaling events in CKDs. Crosstalk between these factors plays a role in the pathogenesis and progression of CKDs. Therapeutic strategy of targeting SLs metabolism defects for CKDs through modulation of the enzymes responsible for SLs metabolism defects is also discussed.