Helicobacter pylori CagA promotes gastric cancer immune escape by upregulating SQLE
Sifan Liu1, Nan Zhang2, Xu Ji1
1Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, State Key Laboratory for Digestive Health, National Clinical Research Center of Digestive Diseases, Beijing Digestive Disease Center, Beijing, 100050, China.
Abstract:
Helicobacter pylori (H. pylori) infection is a well-established risk factor for gastric cancer, primarily due to its virulence factor, cytotoxin-associated gene A (CagA). Although PD-L1/PD-1-mediated immune evasion is critical in cancer development, the impact of CagA on PD-L1 regulation remains unclear. This study revealed that H. pylori CagA upregulated squalene epoxidase (SQLE) expression, a key enzyme in the cholesterol biosynthesis pathway. Elevated SQLE activity increased cellular palmitoyl-CoA levels, enhancing PD-L1 palmitoylation while decreasing its ubiquitination. This ultimately increases PD-L1 stability, suppressing T cell activity and facilitating immune evasion in gastric cancer. In summary, our findings highlight the crucial role of the CagA-SQLE-PD-L1 axis in gastric cancer progression, suggesting potential therapeutic strategies for targeting CagA-positive gastric cancer.
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