Ilimaquinone Induces the Apoptotic Cell Death of Cancer Cells by Reducing Pyruvate Dehydrogenase Kinase 1 Activity

• Published in: International journal of molecular sciences Vol. 21; no. 17; p. 6021
• Main Authors: Kwak, Choong-Hwan, Jin, Ling, Han, Jung Ho, Han, Chang Woo, Kim, Eonmi, Cho, MyoungLae, Chung, Tae-Wook, Bae, Sung-Jin, Jang, Se Bok, Ha, Ki-Tae
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.08.2020; MDPI
• Subjects: A549 Cells; Adenosine triphosphate; Adenosine Triphosphate - metabolism; Animals; Antineoplastic Agents - pharmacology; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Cancer; Carcinoma, Lewis Lung; Cell death; Cell Line, Tumor; Cell viability; Colorectal cancer; Computer applications; Computer simulation; Cytotoxicity; Dehydrogenases; Depolarization; Energy metabolism; Enzymes; Glycolysis; Humans; ilimaquinone; Intelligence; Kinases; Lactic acid; Lung cancer; Medical prognosis; Membrane potential; Mice; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Oxidative phosphorylation; Oxygen consumption; Phosphorylation; Phosphorylation - drug effects; Porifera - chemistry; Pyruvate Dehydrogenase (Lipoamide) - genetics; Pyruvate Dehydrogenase (Lipoamide) - metabolism; Pyruvate Dehydrogenase Acetyl-Transferring Kinase - antagonists & inhibitors; Pyruvate Dehydrogenase Acetyl-Transferring Kinase - chemistry; Pyruvate Dehydrogenase Acetyl-Transferring Kinase - metabolism; pyruvate dehydrogenase kinase 1; Pyruvic acid; Quinones; Quinones - pharmacology; Reactive Oxygen Species - metabolism; Sesquiterpene quinone; Sesquiterpenes - pharmacology; Warburg effect; apoptosis; pyruvate dehydrogenase kinase 1; ilimaquinone; glycolysis; Warburg effect
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21176021

In cancer cells, aerobic glycolysis rather than oxidative phosphorylation (OxPhos) is generally preferred for the production of ATP. In many cancers, highly expressed pyruvate dehydrogenase kinase 1 (PDK1) reduces the activity of pyruvate dehydrogenase (PDH) by inducing the phosphorylation of its E1α subunit (PDHA1) and subsequently, shifts the energy metabolism from OxPhos to aerobic glycolysis. Thus, PDK1 has been regarded as a target for anticancer treatment. Here, we report that ilimaquinone (IQ), a sesquiterpene quinone isolated from the marine sponge , might be a novel PDK1 inhibitor. IQ decreased the cell viability of human and murine cancer cells, such as A549, DLD-1, RKO, and LLC cells. The phosphorylation of PDHA1, the substrate of PDK1, was reduced by IQ in the A549 cells. IQ decreased the levels of secretory lactate and increased oxygen consumption. The anticancer effect of IQ was markedly reduced in PDHA1-knockout cells. Computational simulation and biochemical assay revealed that IQ interfered with the ATP binding pocket of PDK1 without affecting the interaction of PDK1 and the E2 subunit of the PDH complex. In addition, similar to other pyruvate dehydrogenase kinase inhibitors, IQ induced the generation of mitochondrial reactive oxygen species (ROS) and depolarized the mitochondrial membrane potential in the A549 cells. The apoptotic cell death induced by IQ treatment was rescued in the presence of MitoTEMPO, a mitochondrial ROS inhibitor. In conclusion, we suggest that IQ might be a novel candidate for anticancer therapeutics that act via the inhibition of PDK1 activity.