VLX600 - is a lipophilic cation-based triazinoindolyl-hydrazone compound and mitochondrial oxidative phosphorylation (OxPhos) inhibitor, with potential antineoplastic activity. VLX600 is designed to increase the efficacy of radiotherapy and to kill cancer cells that survive traditional chemotherapy. VLX 600 is a small molecule that inhibits deubiquitinating enzymes USP14 (a ubiquitin thiolesterase) and UCHL5 (a carboxypeptidase). Upon infusion, in normal cells and proliferating tumor cells where glucose is readily available, inhibition of OxPhos by VLX600 induces a hypoxia-inducible factor 1-alpha (HIF-1alpha)-dependent shift to, and an increase in glycolysis. Glycolysis alone does not produce enough energy to support the growth of tumor cells in this environment, and the induction of autophagy occurs. In the metabolically compromised tumor microenvironment, the availability of oxygen and glucose is limited due to poor vascularization and perfusion of tumor micro-areas. Tumor cells growing in this environment are thus unable to compensate for decreased mitochondrial function by increasing glycolysis. This leads to nutrient depletion, decreased energy production, induction of autophagy, tumor cell death and an inhibition of cell proliferation in quiescent tumor cells. Mitochondrial OxPhos, which is hyperactivated in cancer cells, plays a key role in the promotion of cancer cell proliferation. VLX-600 is in phase I clinical trials for the treatment of solid tumours. This compound was originally jointly discovered and developed by Vivolux and Karolinska Institute.