Figure 3. . Effect of carbon monoxide on steady state levels of transsulfuration/glutathione biosynthesis metabolites, as measured by liquid chromatography-mass spectrometry, and NADPH/NADP⁺ in human breast cancer cells.

CO inhibits CBS mediated production of cystathionine and H₂S, downregulating Nrf2. Downregulation of Nrf2, in turn, attenuates expression of GCL, GS and G6PD, antioxidant genes downstream involved in GSH biosynthesis/regeneration of GSH from GSSG. Data representative of at least n = 3 individual experiments.

*p< 0.05.

CBS: Cystathionine β-synthase; CO: Carbon monoxide; GS: Glutathione synthase; GSH: Glutathione; GSSG: Glutathione disulfide; H₂S: Hydrogen sulfide; Nrf2: Nuclear factor (erythroid-derived 2)-like 2; GCL: Glutamate-cysteine ligase; G6PD: Glucose 6-phosphate dehydrogenase.