Clotrimazole Preferentially Inhibits Human Breast Cancer Cell Proliferation, Viability and Glycolysis

BACKGROUND: Clotrimazole is an azole derivative with promising anti-cancer effects. This drug interferes with the activity of glycolytic enzymes altering their cellular distribution and inhibiting their activities. The aim of the present study was to analyze the effects of clotrimazole on the growth pattern of breast cancer cells correlating with their metabolic profiles. METHODOLOGY/PRINCIPAL FINDINGS: Three cell lines derived from human breast tissue (MCF10A, MCF-7 and MDA-MB-231) that present increasingly aggressive profiles were used. Clotrimazole induces a dose-dependent decrease in glucose uptake in all three cell lines, with K(i) values of 114.3±11.7, 77.1±7.8 and 37.8±4.2 µM for MCF10A, MCF-7 and MDA-MB-231, respectively. Furthermore, the drug also decreases intracellular ATP content and inhibits the major glycolytic enzymes, hexokinase, phosphofructokinase-1 and pyruvate kinase, especially in the highly metastatic cell line, MDA-MB-231. In this last cell lineage, clotrimazole attenuates the robust migratory response, an effect that is progressively attenuated in MCF-7 and MCF10A, respectively. Moreover, clotrimazole reduces the viability of breast cancer cells, which is more pronounced on MDA-MB-231. CONCLUSIONS/SIGNIFICANCE: Clotrimazole presents deleterious effects on two human breast cancer cell lines metabolism, growth and migration, where the most aggressive cell line is more affected by the drug. Moreover, clotrimazole presents little or no effect on a non-tumor human breast cell line. These results suggest, at least for these three cell lines studied, that the more aggressive the cell is the more effective clotrimazole is

Allosteric regulation of 6-phosphofructo-1-kinase activity of fat body and flight muscle from the bloodsucking bug Rhodnius prolixus

6-phosphofructo-1-kinase (phosphofructokinase; PFK) activity from Rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. The activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 &plusmn; 1.4 U/mg) than in fat body extracts (3.6&plusmn;0.4 U/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. Muscle extracts are more responsible than fat body to ATP and fructose 6-phosphate, both substrates of PFK. Allosteric regulation exerted by different effectors such as ADP, AMP and fructose 2,6-phosphate presented a singular pattern for each tissue. Optimal pH (8.0-8.5) and sensitivity to pH variation was very similar, and citrate was unable to inhibit PFK activity in both extracts. Our results suggest the existence of a particular PFK activity for each tissue, with regulatory patterns that are consistent with their physiological roles.<br>A atividade da fosfofrutocinase (PFK) de Rodnius prolixus, um inseto hematófago, o qual vôa somente pequenas distâncias, foi medida e comparada em dois tecidos metabolicamente ativos - músculo de asa e corpo gorduroso. A atividade desta importante enzima glicolítica regulatória foi muito mais pronunciada em músculo de asa (15,1 ±1,4 U/mg) do que em extrato de corpo gorduroso (3,6 ±0,4 U/mg) embora este último tenha apresentado níveis mais altos da enzima por quantidade de proteína, como medido por western-blotting. Extratos de músculo foram mais responsivos do que corpo gorduroso para ATP e frutose-6-fosfato, ambos substratos da PFK. A regulação alostérica exercida por diferentes efetores tais como ADP, AMP, frutose-2,6-bisfosfato apresentou um padrão singular para cada tecido. O pH ótimo (8,0-8,5) e a sensibilidade a variações de pH, foram muito similares e o citrato foi incapaz de inibir a atividade da PFK em ambos os extratos. Nossos resultados sugerem a existência de uma atividade particular da PFK para cada tecido com padrões regulatórios que são consistentes com suas funções fisiológicas