Exosomal miR-141-3p Induces Gemcitabine Resistance in Biliary Tract Cancer Cells

Gemcitabine (GEM)-based chemotherapy has been established as the core multimodal therapy for biliary tract cancer (BTC). However, the prognosis of BTC is unfavorable because of its resistance to GEM. Exosomes play important roles in the regulation of tumor progression and metastasis, immune dysregulation, and chemoresistance. This study investigated the effects of exosomes on GEM resistance in BTC.

The human intrahepatic cholangiocarcinoma cell line CC-LP-1, its GEM-resistant (GR) derivative cell line CC-LP-1-GR, and the human intrahepatic cholangiocarcinoma cell lines HuCCA-1 and HuCCT1, were used. GEM resistance was examined by measuring cell viability in the presence of GEM using an MTS assay. Exosomes were isolated using ultracentrifugation and quantified using ELISA. Comprehensive expression analysis was performed using RNA sequencing. The effects of microRNAs were examined by miRNA mimic transfection.

The conditioned medium and exosomes derived from CC-LP-1-GR cells enhanced the GEM resistance of parental CC-LP-1 cells. In the presence of GEM, the p53 pathway was negatively enriched in CC-LP-1-GR and CC-LP-1 cells treated with exosomes from CC-LP-1-GR (rExo) compared to CC-LP-1 cells. The expression of miR-141-3p was higher in rExos than in CC-LP-1 cells. CC-LP-1 cells transfected with miR-141-3p mimic showed significantly (p<0.05) increased viability in the presence of GEM.

A GEM-resistant human BTC cell line, CC-LP-1-GR, may acquire resistance to GEM by exosomes containing miR-141-3p.