Putative pathways fueling anaerobic mitochondrial respiration

Tumor interiors undergo prolonged anoxia; however, the pathways involved have not been identified. Since NO and H2S function in prokaryotic anaerobic respiration, the effect their pathway elements have on HeLa 229 cell viability was measured after 10 days anaerobic incubation. Arginine or xanthine (NO pathway precursors) increased cell viability (13.1- and 4.4-fold, respectively). The H2S pathway precursor, cysteine, also enhanced viability (9.8-fold), as did H2S donor GYY4137, or inhibitor of glutathione synthesis, propargylglycine, (40- and 85-fold, respectively). These results demonstrate that cell viability after extended anaerobic incubation (10 days) can be modulated by affecting NO or H2S pathways.