Objective Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal hepatobiliary malignancy with an increasing incidence annually. Extensive research has elucidated the existence of a reciprocal interaction between platelets and cancer cells, which promotes tumor proliferation and metastasis. This study aims to investigate the function and mechanism underlying iCCA progression driven by the interplay between platelets and tumor cells, aiming to provide novel therapeutic strategies for iCCA. Methods The associations between platelets and cancer development were investigated by analyzing the peripheral blood platelet count, degree of platelet activation and infiltration in the microenvironment of patients with iCCA. By co-culturing tumor cells with platelets, the influence of platelet stimulation on the epithelial-mesenchymal transition (EMT), proliferation, and metastasis of iCCA cells was assessed through in vitro and in vivo experiments. Quantitative proteomic profiling was conducted to identify key downstream targets that were altered in tumor cells following platelet stimulation. The RNA interference technique was utilized to investigate the impacts of gene silencing on the malignant biological behaviors of tumor cells. Results Compared with healthy adults, patients with iCCA presented significantly higher levels of peripheral blood platelet counts, platelet activation and infiltration degrees, which were also found to be correlated with patient prognosis. Platelet stimulation greatly facilitated the EMT of iCCA cells, leading to enhanced proliferative and metastatic capabilities. Mechanistically, proteomic profiling identified a total of 67 up-regulated and 40 down-regulated proteins in iCCA cells co-cultured with platelets. Among these proteins, two elevated targets ILK and ITGB3, were further demonstrated to be partially responsible for platelet-induced iCCA progression, which might depend on their regulatory effects on FAK/PI3K/AKT signaling transduction. Conclusions Our data revealed that platelet-related indices were abnormally ascendant in iCCA patients compared to healthy adults. Co-culturing with platelets enhanced the progression of EMT, and the motility and viability of iCCA cells in vitro and in vivo. Proteomic profiling discovered that platelets promoted the development of iCCA through FAK/PI3K/AKT pathway by means of elevating the expression of ILK and ITGB3, indicating that both proteins are promising therapeutic targets for iCCA with the guidance of platelet-related indices.

Objective Hepatocellular carcinoma (HCC) is an extremely deadly cancer with few effective therapeutic options available. Ceramide synthases (CERS), a family of enzymes that regulate sphingolipid metabolism, have been suggested to play a role in cancer initiation and progression. Whereas the specific functions of CERS in HCC pathogenesis have not yet been fully elucidated. Methods The TCGA and ICGC databases were employed to analyze the expression levels and clinical relevance of CERS genes in HCC. Functional enrichment analyses were performed to identify pathways and functions associated with CERS5. The correlation between CERS5 and the tumor immune microenvironment was investigated. The mutation landscape and immunotherapy efficacy were evaluated. Functional experiments in vitro were conducted to assess CERS5’s impact on HCC cell proliferation and invasion. Results Aberrant expression of the CERS family was detected not only in HCC but also in other cancers, and has been linked to both overall survival and disease-free survival. Among the CERS family members, CERS5 was identified as the only prognosis-related gene, with up-regulated in HCC validated in the ICGC database and clinical tissue samples. Higher expression levels of CERS5 were associated with a poorer prognosis as well as an advanced pathologic stage and grade, as confirmed by the TCGA and ICGC databases. Besides, a prognostic nomogram combining pathologic stage, tumor status, and the expression of CERS5 was established and further validated, which suggested a favorable value for prognosis prediction. Functional enrichment analyses showed that the overexpression of CERS5 resulted in enriched pathways associated with carcinogenesis, drug metabolism, the PI3K/AKT/mTOR signaling pathway, and cancer immune-related pathways. In addition, the overexpression of CERS5 correlated positively with the expression of genes associated with immunogenic cell death modulators and immune checkpoints, levels of immune cell infiltration, and immunotherapy response, which was featured in an immunologically “hot” environment in the tumor microenvironment. Finally, the functional experiments showed that CERS5 knockdown has been shown to inhibit the growth and invasion of hepatocellular carcinoma, potentially through targeting the PI3K/AKT/mTOR signaling pathway. Conclusions Based on our findings, CERS5 appears to have great potential as both a precise prognostic biomarker and a novel therapeutic target in HCC.