Small Molecule Activators of Human Pyruvate Kinase for Treatment of Cancer and Enzyme-Deficient Hemolytic Anemia

NIH investigators have discovered a series of small compounds with the potential to treat a variety of cancers as well as hemolytic anemia. Contrary to most cancer medications, these molecules can be non-toxic to normal cells because they target a protein specific to the metabolic pathways in tumors, thus representing a significant clinical advantage over less-specific chemotherapeutics.

The invention described here is a series of small molecules that activate pyruvate kinase (PK) isoform M2. PK-M2 is a critical metabolic enzyme that is affected in all forms of cancer. Inactivation of PK-M2 leads to a buildup of metabolic intermediates inside the cell. Tumor cells require a buildup of metabolic intermediates in order to undergo rapid cell growth and proliferation. Hence, activation of PK-M2 in tumor cells may prevent the buildup of metabolic intermediates and thereby stall tumor cell proliferation or destroy the tumor cells. Further, while in normal adult cells only PK isoforms R, L, or M1 are active, in all tumors only PK-M2 is active. Therefore, PK-M2 activation would affect only tumor cells, and small-molecule PK-M2 activators are not expected to be toxic to healthy cells.

In addition, in patients with PK-R deficiency the buildup of metabolic intermediates in red blood cells ultimately leads to the loss of water from the cells and cell death. Small-molecule induced activation of PK-R in PK-deficient red blood cells may enhance vitality of these cells and decrease or eliminate enzyme-deficient hemolytic anemia in a patient.