Fig. 1
From: The role of Aquaporins in tumorigenesis: implications for therapeutic development
Role of AQP1 in Cancer Progression. Left- Putative mechanism of hypoxia-facilitated AQP1 expression in tumour cells. Hayashi and colleagues postulated that hypoxia facilitates AQP1 expression through glycolysis [87]. Lactic acid is produced during glycolysis, which also boosts the transcription of AQP1 and cathepsin B via E-box/ChoRE.Cathepsin Bcontributes to tumor invasion. An excess of H+ and intracellular acidosis are brought on by the increased lactic acid. Intracellular carbonic anhydrases (CA) catalyze the process that changes the excess H+ into H2O and CO2 from the interaction with HCO3-. While CO2 may leave the cell through the central hole of the AQP1 tetramer or diffuse across the plasma membrane, extra H2O created leaves the tumor cell through the water pores of the up-regulated AQP1 to prevent cytotoxic oedema. Right- Proposed mechanisms how AQP1 is involved with different signaling pathways to enhance tumour cell invasion and metastasis