Platelets promote metastasis of intrahepatic cholangiocarcinoma through activation of TGF-β/Smad2 pathway

Abstract

Intrahepatic cholangiocarcinoma (ICC), an aggressive liver cancer, lacks simple and accurate clinical tests, which poses challenges to postoperative diagnosis and treatment. Recent studies have indicated that platelet levels might be relevant to the postoperative prognosis of ICC. However, their prognostic significance in ICC remains unclarified. This study included 218 ICC patients who underwent hepatic resection. Comprehensive analyses of patients' postoperative prognosis were conducted primarily focusing on their platelet levels associated with prognostic traits. To further investigate the underlying mechanism between platelet levels and patients' postoperative prognosis, we elucidated the association between platelets and tumor metastasis using HCCC-9810 and HUCC-T1 cells as well as mouse models. In the retrospective cohort study, elevated serum platelet levels (≥300 × 10⁹/L) or tumoral platelet levels (≥0.23) individually indicated an unfavorable postoperative prognosis in individuals with ICC. Multivariate analysis showed that tumoral platelet levels can be an independent prognostic factor, while the loss of prognostic superiority of serum platelet levels in the analysis may be attributed to the influence of confounding inclusion variables. Epithelial/mesenchymal transition (EMT) marker expression changes in HCCC-9810 and HUCC-T1 cells with platelet treatment were analyzed to understand how platelets contribute to ICC malignant recurring progression. The significant role of the TGF-β/Smad2 pathway in ICC metastasis was identified. In addition, aspirin was found to have the potential to reduce ICC metastasis by inhibiting platelet function. In conclusion, this study indicated that ICC patients with postoperative serum platelet levels ≥300 × 10⁹/L or tumoral platelet levels ≥0.23 have significantly higher risk of poor postoperative prognosis. This is due to platelet-derived TGFβ1 leading to EMT in ICC cells, thus promoting tumor metastasis.