The HK2 Dependent "Warburg Effect" and Mitochondrial Oxidative Phosphorylation in Cancer:Targets for Effective Therapy with 3-Bromopyruvate

This review summarizes the current state of knowledge about the metabolism of cancer cells, especially with respect to the “Warburg” and “Crabtree” effects. This work also summarizes two key discoveries, one of which relates to hexokinase-2 (HK2), a major player in both the “Warburg effect” and cancer cell immortalization. The second discovery relates to the finding that cancer cells, unlike normal cells, derive as much as 60% of their ATP from glycolysis via the “Warburg effect”, and the remaining 40% is derived from mitochondrial oxidative phosphorylation. Also described are selected anticancer agents which generally act as strong energy blockers inside cancer cells. Among them, much attention has focused on 3-bromopyruvate (3BP). This small alkylating compound targets both the “Warburg effect”, i.e., elevated glycolysis even in the presence oxygen, as well as mitochondrial oxidative phosphorylation in cancer cells. Normal cells remain unharmed. 3BP rapidly kills cancer cells growing in tissue culture, eradicates tumors in animals, and prevents metastasis. In addition, properly formulated 3BP shows promise also as an effective anti-liver cancer agent in humans and is effective also toward cancers known as “multiple myeloma”. Finally, 3BP has been shown to significantly extend the life of a human patient for which no other options were available. Thus, it can be stated that 3BP is a very promising new anti-cancer agent in the process of undergoing clinical development

The HK2 Dependent "Warburg Effect" and Mitochondrial Oxidative Phosphorylation in Cancer:Targets for Effective Therapy with 3-Bromopyruvate

This review summarizes the current state of knowledge about the metabolism of cancer cells, especially with respect to the “Warburg” and “Crabtree” effects. This work also summarizes two key discoveries, one of which relates to hexokinase-2 (HK2), a major player in both the “Warburg effect” and cancer cell immortalization. The second discovery relates to the finding that cancer cells, unlike normal cells, derive as much as 60% of their ATP from glycolysis via the “Warburg effect”, and the remaining 40% is derived from mitochondrial oxidative phosphorylation. Also described are selected anticancer agents which generally act as strong energy blockers inside cancer cells. Among them, much attention has focused on 3-bromopyruvate (3BP). This small alkylating compound targets both the “Warburg effect”, i.e., elevated glycolysis even in the presence oxygen, as well as mitochondrial oxidative phosphorylation in cancer cells. Normal cells remain unharmed. 3BP rapidly kills cancer cells growing in tissue culture, eradicates tumors in animals, and prevents metastasis. In addition, properly formulated 3BP shows promise also as an effective anti-liver cancer agent in humans and is effective also toward cancers known as “multiple myeloma”. Finally, 3BP has been shown to significantly extend the life of a human patient for which no other options were available. Thus, it can be stated that 3BP is a very promising new anti-cancer agent in the process of undergoing clinical development

Mitochondrial Function Are Disturbed in the Presence of the Anticancer Drug, 3-Bromopyruvate

3-bromopuryvate (3-BP) is a compound with unique antitumor activity. It has a selective action against tumor cells that exhibit the Warburg effect. It has been proven that the action of 3-BP is pleiotropic: it acts on proteins, glycolytic enzymes, reduces the amount of ATP, induces the formation of ROS (reactive oxygen species), and induces nuclear DNA damage. Mitochondria are important organelles for the proper functioning of the cell. The production of cellular energy (ATP), the proper functioning of the respiratory chain, or participation in the production of amino acids are one of the many functions of mitochondria. Here, for the first time, we show on the yeast model that 3-BP acts in the eukaryotic cell also by influence on mitochondria and that agents inhibiting mitochondrial function can potentially be used in cancer therapy with 3-BP. We show that cells with functional mitochondria are more resistant to 3-BP than rho0 cells. Using an MTT assay (a colorimetric assay for assessing cell metabolic activity), we demonstrated that 3-BP decreased mitochondrial activity in yeast in a dose-dependent manner. 3-BP induces mitochondrial-dependent ROS generation which results in ∆sod2, ∆por1, or ∆gpx1 mutant sensitivity to 3-BP. Probably due to ROS mtDNA lesions rise during 3-BP treatment. Our findings may have a significant impact on the therapy with 3-BP

Vmr 1p is a novel vacuolar multidrug resistance ABC transporter in Saccharomyces cerevisiae

The Saccharomyces cerevisiae Yhl035p/Vmr1p is an ABC transporter of the MRP subfamily that is conserved in all post Whole Genome Duplication species. The deletion of the YHL035 gene caused growth sensitivity to several amphiphilic drugs such as cycloheximide, 2,4-dichlorophenoxyacetic acid, 2,4-dinitrophenol as well as to cadmium and other toxic metals. Vmr1p-GFP was located in the vacuolar membrane. The ATP-dependent transport of a DNP-S-glutathione conjugate was reduced in a vesicular fraction from the VMR1 deletant. The energy-dependent efflux of rhodamine 6G was increased by VMR1 deletion. Growth sensitivity to cadmium of the VMR1-deleted strain was more pronounced in glycerol/ethanol than in glucose-grown cells. The VMR1 promoter had higher activity when grown in glycerol/ethanol compared with glucose. In glucose, the VMR1 promoter was activated by the deletion of the glucose-dependent repressor ADR1

The YJL185C, YLR376C and YJR129C genes of Saccharomyces cerevisiae are probably involved in regulation of the glyoxylate cycle

The ER24 aci (acidification) mutant of Saccharomyces cerevisiae excreting protons in the absence of glucose was transformed with a multicopy yeast DNA plasmid library. Three different DNA fragments restored the wild-type phenotype termed Aci- because it does not acidify the complete glucose medium under the tested conditions. Molecular dissection of the transforming DNA fragments identified two multicopy suppressor genes YJL185C, YJR129C and one allelic YLR376C. Disruption of either of the three genes in wild-type yeast strain resulted in acidification of the medium (Aci+ phenotype) similarly to the original ER24 mutant. These data indicate the contribution of the ER24 gene product Ylr376Cp and of the two suppressor gene products Yjl185Cp and Yjr129Cp to a complex regulation of the glyoxylate cycle in yeast

Transport and cytotoxicity of the anticancer drug 3-bromopyruvate in the yeast Saccharomyces cerevisiae.

We have investigated the cytotoxicity in Saccharomyces cerevisiae of the novel antitumor agent 3-bromopyruvate (3-BP). 3-BP enters the yeast cells through the lactate/pyruvate H(+) symporter Jen1p and inhibits cell growth at minimal inhibitory concentration of 1.8 mM when grown on non-glucose conditions. It is not submitted to the efflux pumps conferring Pleiotropic Drug Resistance in yeast. Yeast growth is more sensitive to 3-BP than Gleevec (Imatinib methanesulfonate) which in contrast to 3-BP is submitted to the PDR network of efflux pumps. The sensitivity of yeast to 3-BP is increased considerably by mutations or chemical treatment by buthionine sulfoximine that decrease the intracellular concentration of glutathione