Role of cancer stem cell heterogeneity in intrahepatic cholangiocarcinoma.

Background: Intrahepatic cholangiocarcinoma (ICC) is a highly invasive bile duct cancer with poor prognosis due to frequent recurrence and limited effective treatments. Cancer stem cells (CSCs) contribute to ICC's therapeutic resistance and recurrence, driven by distinct cellular subpopulations with variable tumorigenic properties. Recent advances in single-cell RNA sequencing (scRNA-seq) have enabled a deeper exploration of cellular heterogeneity in tumors, offering insights into unique CSC subgroups that impact ICC progression and patient outcomes. This study aimed to investigate the effect of CSC heterogeneity on the prognosis of ICC.

Methods: The scRNA-seq dataset GSE142784 was retrieved from the Gene Expression Omnibus (GEO) database, and Bulk RNA-seq data were obtained from The Cancer Genome Atlas (TCGA) databases. Hallmarks and AUCell R package were adopted for analyzing the signaling pathway activity, CellChat for observing cell communication between subgroups, and SCENIC for analyzing transcription factors expression. The immune cell infiltration and drug sensitivity of the model were analyzed using the CIBERSORT algorithm and the "pRRophetic" R packages, respectively. And immunohistochemistry (IHC) tests were used to evaluate expression of transcription factors in ICC patients.

Results: Based on scRNA-seq data, five clusters (DLK⁺, CD13⁺, CD90⁺, CD133⁺, and other cholangiocarcinoma cells) were observed in ICC, which presented different signaling pathway activities, such as HSF1 and STAT1 were highly expressed in the CD133 cluster, and consistent with the results of IHC tests. Pathways like Notch and Wnt/β-catenin signaling transferred among above subgroups. Further, subgroups favored varied immune response and drug sensitivity, and CD133⁺ subgroup patients showed significantly shortened recurrence-free survival (RFS).

Conclusions: Configuring the subgroup of ICC is helpful for predicting the prognosis and drug resistance in ICC and can provide new strategies for cancer treatment.