GALNT6-glycosylated LRG1 mediates the interaction between M2 macrophages and pancreatic cancer cells by activating CCR1/PI3K/AKT axis.

Pancreatic cancer (PC) is a malignant tumor that often presents no obvious symptoms in its early stages, leading to late diagnosis and poor prognosis. Therefore, developing molecular markers for PC is essential for improving early diagnosis, optimizing treatment strategies, and enhancing patient outcomes. In this study, PC tissue and matched adjacent non-cancerous tissue were collected from patients. For in vitro analysis, the PC cell lines BxPC-3 and SW1990 were used. M2 macrophages were induced in THP-1 cells. Gene expression at both mRNA and protein levels was measured using real-time quantitative PCR and Western blotting. Cell counting kit-8 assay was used to evaluate cell activity. Flow cytometry was used to assess the cell apoptosis rate and M2 macrophage biomarkers. Transwell and wound-healing assays were used to determine cell migration and invasiveness. Co-immunoprecipitation assay was used to evaluate the binding relationship between leucine-rich α-2 glycoprotein 1 (LRG1), chemokine receptor 1 (CCR1), and GALNT6. LRG1 expression was upregulated in PC tissues compared to that in normal tissues. Co-culture with M2 macrophages enhanced gemcitabine (GEM) resistance, cell migration, and PC cell invasion. LRG1 overexpression in PC cells enhanced the effect of M2 macrophage cells to exacerbate GEM resistance, cell migration, and invasion, while LRG1 knockdown exhibited an opposite effect. LRG1 interacted with CCR1 to enhance PI3K/AKT signaling, thereby affecting GEM resistance, migration, and PC cell invasion. Moreover, GALNT6 was confirmed as an upstream regulator of LRG1, which glycosylated LRG1 and increased its stability. Rescue experiments demonstrated that GALNT6 promoted GEM resistance, movement, and invasion abilities of PC cells by regulating LRG1. The role of LRG1 in the interaction between PC cells and M2 macrophages was also verified in the xenograft model. These findings demonstrate that GALNT6-glycosylated LRG1 mediates the interaction between M2 macrophages and PC cells by activating CCR1. This study may provide promising therapeutic targets for PC treatment.