Non-metabolic functions of pyruvate kinase M2: PKM2 in tumorigenesis and therapy resistance.

Cancer is the disease of uncontrollably dividing cells in the body. As cancer cells proliferate at higher rates, they need more energy in a short time necessitating deregulation of energy-generating pathways for their benefit. Although oxidative phosphorylation generates more energy from a glucose molecule, cancer cells have a tendency to enhance aerobic glycolysis by consuming more glucose and producing lactate as a by-product even if oxygen is present. In addition to the generation of rapid energy to fulfill their increasing demands, this strategy also provides the use of glucose metabolites such as lactate as a source for the synthesis of anabolic molecules, such as nucleotides, amino acids, and lipids during the rapid phase of the proliferation. Pyruvate kinase M2 (PKM2) is an isoform of pyruvate kinase, which mediates the balancing of energy generation mechanisms during the anabolic and catabolic events. Due to its vital role in glycolysis, PKM2 has been investigated to target cancer cell metabolism for several years. However, recent studies demonstrate that PKM2 may also promote cancer progression by regulating core steps in metastasis such as migration, angiogenesis, and stemness. Of note, it is estimated that 90% of cancer-related deaths are due to metastasis. This review is intended to summarize the recent advances in the non-metabolic roles of PKM2 in cancer progression and to indicate its potential uses for the development of new treatment strategies.