Carbon Chain Length in a Novel Anticancer Aryl-Urea Fatty Acid Modulates Mitochondrial Targeting, Reactive Oxygen Species Production and Cell Killing.

The cancer cell mitochondrion could be a promising target for the development of new anticancer agents. 16-([3-chloro-5-(trifluoromethyl)-phenyl]carbamoylamino)hexadecanoic acid (2) is a novel aryl-urea fatty acid that targets the mitochondrion in MDA-MB-231 breast cancer cells and activates cell death. In the present study, the relationships between alkyl chain length in 2 analogues, mitochondrial disruption and cell killing were evaluated. The chain-contracted C13-analogue 7 c optimally disrupted the mitochondrial membrane potential (IC50 4.8±0.8 µM). In addition, annexin V-FITC/7-AAD assays demonstrated that 7 c was the most effective cell killing analogue and C11 BODIPY (581/591) assays demonstrated that 7 c was also most effective in generating reactive oxygen species in MDA-MB-231 cells. Together, carbon chain length is a key factor that determines the capacity of 2 analogues to disrupt the mitochondrial membrane, induce the production of reactive oxygen species and kill breast cancer cells. As an aryl-urea with enhanced activity and improved drug-like properties, 7 c may be a suitable lead molecule for entry into a program of development of these molecules as anticancer agents.

Carbon Chain Length Modulates MDA-MB-231 Breast Cancer Cell Killing Mechanisms by Mitochondrially Targeted Aryl-Urea Fatty Acids.

Targeting the tumor cell mitochondrion could produce novel anticancer agents. We designed an aryl-urea fatty acid (1 g; 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid) that disrupted the mitochondrion and decreased MDA-MB-231 breast cancer cell viability. To optimize the aryl-ureas the present study evaluated mitochondrial targeting by 1 g analogues containing alkyl chains between 10-17 carbons. Using the dye JC-1, the C12-C17 analogues efficiently disrupted the mitochondrial membrane potential (IC50 s 3.5±1.2 to 7.6±1.1 µM) and impaired ATP production; shorter analogues were less active. 7-Aminoactinomycin D/annexin V staining and flow cytometry showed that these agents activated the killing mechanisms of necrosis and apoptosis to varying extents (7-aminoactinomycin D/annexin V staining ratios 4.3-6.0). Indeed, 1 g and its C17 analogue preferentially activated necrosis and apoptosis, respectively (ratios 2.1 and 16). Taken together, alkyl chain length is a determinant of mitochondrial targeting by aryl-ureas and can be varied to develop analogues that activate apoptosis or necrosis in a regulated fashion.

Carboxylate Analogues of Aryl-Urea-Substituted Fatty Acids That Target the Mitochondria in MDA-MB-231 Breast Cancer Cells to Promote Cell Death.

Selective targeting of the tumor cell mitochondrion is a viable approach for the development of anticancer agents because the organelle is functionally different from the mitochondria of normal cells. We recently developed a novel aryl-urea fatty acid, 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid (1) that was found to disrupt mitochondria and to activate apoptosis in MDA-MB-231 breast cancer cells. However, there is currently little information on the structural requirements for the activity of compound 1 analogues. The present study evaluated the role of the carboxylic acid group on the anticancer activity of 1. Bioisosteric replacement of the carboxylate in 1 maintained activity. Thus, like 1, the sulfonic acid analogue 1-SA and the oxo-thiadiazole analogue 1-OT were also found to target the mitochondrion and to activate cell killing capacity. The hydroxamic acid analogue 1-HA also killed MDA-MB-231 cells, but its onset of action was slower than that of 1-SA and 1-OT. In contrast, replacement of the carboxylate with non-bioisosteric amido and methylamido groups produced analogues that minimally altered mitochondrial function and showed little capacity to decrease tumor cell viability. These findings suggest that the carboxylate moiety in the novel mitochondrially targeted agent 1 is an important determinant of the kinetics and efficacy of anticancer cell activities of compound 1 analogues. Further development of carboxylate-modified analogues of aryl-urea fatty acids as potential anticancer agents could now be warranted.

JCL roundtable: lipid-lowering drugs in those older than 75 years of age.

Using drugs in the elderly requires some special considerations; however, there is no question that our older patients benefit tremendously from the use of agents that prevent and/or control many of the risk factors for vascular disease that are most prevalent in the latter years of life. Recently, the American College of Cardiology and the American Heart Association issued guidelines for the management of blood cholesterol elevations. For the first time, little specific guidance was given for the age group older than 75 years of age. The rationale given for this approach was primarily that the data from randomized trials comparing drug therapy to treatment with placebos were inadequate for such recommendations. There was also concern regarding safety in this group. This Roundtable will consider this lack of recommendations in a broader context than statin trials.