Targeting ICAM1/ITGB2 with plumbagin preserves intercellular adhesion and attenuates gastric precancerous lesions.

[BACKGROUND] Gastric precancerous lesions (GPL) represent an essential pathological stage in the transition from normal gastric mucosa to gastric cancer, garnering significant research attention in recent years. Plumbagin demonstrates therapeutic potential against gastric GPL, though its mechanism remains unclear.

[PURPOSE] Investigating the therapeutic efficacy of plumbagin against GPL and its potential molecular mechanisms.

[METHODS] To investigate ICAM1-mediated intercellular adhesion, we used clinical samples, human-derived orgnoids, gastric precancerous cells (MC cells), and ICAM1 cells. Analyzing key mechanisms in GPL through single-cell sequencing data, investigating plumbagin's effects on intercellular adhesion and underlying molecular mechanisms via immunofluorescence and western blotting, and finally employing MST, CETSA and DARTs to detect interactions between plumbagin and its action targets.

[RESULTS] Human-derived gastric organoids and GPL mouse models confirmed plumbagin's therapeutic effects. Our findings revealed a positive correlation between ICAM1/ITGB2 expression and GPL progression, while expression of ZO-1, occludin, and claudin-18 showed a negative correlation. Plumbagin alleviated GPL progression in vitro and in vivo by inhibiting ICAM1-mediated intercellular adhesion. Rescue experiments showed that the therapeutic effect of plumbagin in ICAM1 cells was abolished, and the ICAM1 agonist leukadherin-1 significantly attenuated the effects of plumbagin in GPL organs and mice. The ICAM1 agonist leukadherin-1 attenuated the effects of plumbagin in vitro and in vivo, and the therapeutic efficacy of plumbagin was abolished in ICAM1 cells. Furthermore, MST, CETSA, and DARTs assays confirmed direct binding between plumbagin and ICAM1. Single-point mutation at THR-85 of ICAM1 abolished plumbagin-ICAM1 binding, demonstrating the direct interaction of plumbagin with the THR-85 of ICAM1. Co-immunoprecipitation (Co-IP) indicated that plumbagin disrupted ICAM1/ITGB2 interaction, thereby restoring intercellular adhesion and mitigating GPL pathology.

[CONCLUSION] Plumbagin bound ICAM1 at THR-85, blocks ICAM1/ITGB2 interaction, restored intercellular adhesion, and enhanced therapeutic efficacy against GPL.