LAUSR

BACKGROUND AIMS Cholangiocarcinoma(CCA) is a highly lethal malignancy originating from the biliary ducts. Current CCA diagnostic and prognostic assessments cannot satisfy the clinical requirement. Bile detection is rarely performed and herein we aim to estimate the clinical significance of bile liquid biopsy by assessing bile exosomal concentrations and components. APPROACH RESULTS Exosomes in bile and sera from CCA, pancreatic cancer and common bile duct stone(CBDS) were identified and quantified by TEM, NTA and nanoFCM. Exosomal components were assessed by LC-MS/MS and miRNA-seq. Bile exosomal concentration in different diseases had no significant difference, but miR-182-5p and miR-183-5p were ectopically up-regulated in CCA bile exosomes. High miR-182/183-5p in both CCA tissues and bile indicates poor prognosis. Bile exosomal miR-182/183-5p is secreted by CCA cells, and can be absorbed by biliary epithelium or CCA cells. With xenografts in humanized mice, we showed that bile exosomal miR-182/183-5p promotes CCA proliferation, invasion and EMT by targeting HPGD in CCA cells and mast cells(MCs) and increasing PGE2 generation, which stimulates PTGER1 and increases CCA stemness. In scRNA-seq, HPGD is predominantly expressed in MCs. miR-182/183-5p prompts MC to release VEGF-A release from MC by increasing VEGF-A expression, which facilitates angiogenesis. CONCLUSIONS CCA cells secret exosomal miR-182/183-5p into bile, which targets HPGD in CCA cells and MCs and increases PGE2 and VEGF-A release. PGE2 promotes stemness by activating PTGER1. Our results reveal a type of CCA self-driven progression dependent on bile exosomal miR-182/183-5p and MCs, which is a new interplay pattern of CCA and bile.