The multifaceted roles of sulfane sulfur species in cancer-associated processes

Sulfane sulfur species comprise a variety of biologically relevant hydrogen sulfide (HS)-derived species, including per- and poly-sulfidated low molecular weight compounds and proteins. A growing body of evidence suggests that HS, currently recognized as a key signaling molecule in human physiology and pathophysiology, plays an important role in cancer biology by modulating cell bioenergetics and contributing to metabolic reprogramming. This is accomplished through functional modulation of target proteins via HS binding to heme iron centers or HS-mediated reversible per- or poly-sulfidation of specific cysteine residues. Since sulfane sulfur species are increasingly viewed not only as a major source of HS but also as key mediators of some of the biological effects commonly attributed to HS, the multifaceted role of these species in cancer biology is reviewed here with reference to HS, focusing on their metabolism, signaling function, impact on cell bioenergetics and anti-tumoral properties.