In light of emerging evidence that antioxidants can have cancer-promoting effects, Swamynathan et al. tested potential pro-oxidant interventions (see the Perspective by Pannia and Dowling). In particular, the authors focused on menadione sodium bisulfite, a water-soluble precursor of vitamin K. As the authors anticipated, this menadione derivative suppressed prostate cancer growth. The researchers then examined its mechanism of action and identified the kinase VPS34 (phosphatidylinositol 3-kinase catalytic subunit type 3) as its target. Fortuitously, they realized that a fatal genetic muscle disease called X-linked myotubular myopathy is also linked to a relative excess of VPS34 activity owing to the loss of its antagonist, and dietary supplementation with menadione proved beneficial in a mouse model of this genetic disorder. —Yevgeniya Nusinovich
2 Medical News 