**7. The development of novel cancer therapeutics to improve mitochondrial functions**

In cancer cells, the mitochondrial functions are downregulated but glycolysis is upregulated [7, 8]. Thus, inhibitors of glycolysis/PDHK1/PARP, which target the metabolic switch in cancer cells, could be effective anti-cancer drugs [59]. In general, glycolysis- or glycolytic pathwaytargeting drugs are expected to kill cancer cells specifically. For example, 2-deoxy-d-glucose, cisplatin and 5-FU—which have an inhibitory effect on glycolysis—are used to treat cancer in the clinical setting [177]. However, glycolysis is one of the most essential biological reactions. Thus, glycolysis inhibitors may be harmful or toxic to normal cells. Given that mitochondrial dysfunction is another essential cause of oncogenesis, the improvement of the mitochondria might provide clues that can be used to design innovative next-generation cancer therapies.
