Immune Response in H. pylori-Associated Gastritis and Gastric Cancer

Figure 3

Adenosine obstructs immunity by activating A2AR and migration. Hypoxia induces the release of ATP via ATP-binding cassette (ABC) transporters, pannexin 1 or connexins. Accumulated ATP has two destinations, one of which is to stimulate P2 purinergic receptors (P2XRs and P2YRs) and CD39. The other is that ATP can further be degraded to adenosine to stimulate some various signal pathways, including activation of CD73 and adenosine receptors. The former is capable of releasing MMPs to facilitate the breakdown of ECM and tumor cell migration. The latter activation promotes tumor cell proliferation and angiogenesis through the secretion of VEGF. Moreover, the exosome of some tumor coexpresses CD39 and CD73. Abbreviations: A2AR: a kind of adenosine receptors; MMPs: releasing matrix metalloproteinases; ECM: extracellular matrix; VEGF: vascular endothelial growth factor.