Proton pump inhibitor pantoprazole inhibits gastric cancer metastasis via suppression of telomerase reverse transcriptase gene expression

The effect of proton pump inhibitors (PPIs) on cancer risk has received much attention recently. Over the last two decades, we and others have disclosed that PPIs exerted anticancer effects. Telomerase reverse transcriptase (TERT) is essential for telomere maintenance. The activation of TERT is considered a crucial step in tumorigenesis; therefore, it is a potential therapeutic target against cancer. However, whether PPIs suppress gastric cancer by targeting TERT remains elusive. Our study demonstrated that PPZ treatment repressed TERT expression in gastric cancer cells via regulating TERT promoter activity by disturbing the interaction of STAT3 with the TERT gene. Additionally, PPZ led to chromatin remodeling within the TERT gene and resulted in a more compacted spatial conformation that is known to be associated with gene silencing. PPZ downregulated the TERT gene to inactivate the Wnt/β-catenin signaling pathway and reverse the EMT process, finally inhibiting gastric cancer metastasis both in vitro and in vivo. Our results suggest that PPIs may be potentially developed as effective as well as relatively safe and specific anticancer agents.