Recent advances in the role of endogenous hydrogen sulphide in cancer cells

Hydrogen sulphide (H2S) is a gaseous neurotransmitter that can be self-synthesized by living organisms. With the deepening of research, the pathophysiological mechanisms of endogenous H2S in cancer have been increasingly elucidated: (1) promote angiogenesis, (2) stimulate cell bioenergetics, (3) promote migration and proliferation thereby invasion, (4) inhibit apoptosis and (5) activate abnormal cell cycle. However, the increasing H2S levels via exogenous sources show the opposite trend. This phenomenon can be explained by the bell-shaped pharmacological model of H2S, that is, the production of endogenous (low concentration) H2S promotes tumour growth while the exogenous (high concentration) H2S inhibits tumour growth. Here, we review the impact of endogenous H2S synthesis and metabolism on tumour progression, summarize the mechanism of action of H2S in tumour growth, and discuss the possibility of H2S as a potential target for tumour treatment.