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Abstract Background Intrahepatic cholangiocarcinoma (iCCA) is a highly heterogeneous and lethal hepatobiliary tumor with few therapeutic strategies. The metabolic reprogramming of tumor cells plays an essential role in the development of tumors, while the metabolic molecular classification of iCCA is largely unknown. Here, we performed an integrated multiomics analysis and metabolic classification to depict differences in metabolic characteristics of iCCA patients, hoping to provide a novel perspective to understand and treat iCCA. Methods We performed integrated multiomics analysis in 116 iCCA samples, including whole‐exome sequencing, bulk RNA‐sequencing and proteome analysis. Based on the non‐negative matrix factorization method and the protein abundance of metabolic genes in human genome‐scale metabolic models, the metabolic subtype of iCCA was determined. Survival and prognostic gene analyses were used to compare overall survival (OS) differences between metabolic subtypes. Cell proliferation analysis, 5‐ethynyl‐2'‐deoxyuridine (EdU) assay, colony formation assay, RNA‐sequencing and Western blotting were performed to investigate the molecular mechanisms of diacylglycerol kinase α (DGKA) in iCCA cells. Results Three metabolic subtypes (S1‐S3) with subtype‐specific biomarkers of iCCA were identified. These metabolic subtypes presented with distinct prognoses, metabolic features, immune microenvironments, and genetic alterations. The S2 subtype with the worst survival showed the activation of some special metabolic processes, immune‐suppressed microenvironment and Kirsten rat sarcoma viral oncogene homolog (KRAS)/AT‐rich interactive domain 1A (ARID1A) mutations. Among the S2 subtype‐specific upregulated proteins, DGKA was further identified as a potential drug target for iCCA, which promoted cell proliferation by enhancing phosphatidic acid (PA) metabolism and activating mitogen‐activated protein kinase (MAPK) signaling. Conclusion Via multiomics analyses, we identified three metabolic subtypes of iCCA, revealing that the S2 subtype exhibited the poorest survival outcomes. We further identified DGKA as a potential target for the S2 subtype.

Abstract Mixed lineage kinase domain-like (MLKL) is widely accepted as an executioner of necroptosis, in which MLKL mediates necroptotic signaling and triggers cell death in a receptor-interacting protein kinase 3 (RIPK3)-dependent manner. Recently, it is increasingly noted that RIPK3 is intrinsically silenced in hepatocytes, raising a question about the role of MLKL in hepatocellular carcinoma (HCC). This study reports a previously unrecognized role of MLKL in regulating parthanatos, a programmed cell death distinct from necroptosis. In HCC cells with intrinsic RIPK3 deficiency, knockout of MLKL impedes the orthotopic tumor growth, activates the anti-tumor immune response and enhances the therapeutic effect of immune checkpoint blockade in syngeneic HCC tumor models. Mechanistically, MLKL is required for maintaining the endoplasmic reticulum (ER)-mitochondrial Mg2+ dynamics in HCC cells. MLKL deficiency restricts ER Mg2+ release and mitochondrial Mg2+ uptake, leading to ER dysfunction and mitochondrial oxidative stress, which together confer increased susceptibility to metabolic stress-induced parthanatos. Importantly, pharmacological inhibition of poly(ADP-ribose) polymerase to block parthanatos restores the tumor growth and immune evasion in MLKL-knockout HCC tumors. Together, our data demonstrate a new RIPK3-independent role of MLKL in regulating parthanatos and highlight the role of MLKL in facilitating immune evasion in HCC.

As a rare type of liver cancer, intrahepatic cholangiocarcinoma (ICC) has become an increasingly important malignancy and continues to present significant therapeutic challenges. Since coagulopathy is associated with poor prognosis in hepatocellular carcinoma (HCC), and prognostic factors of ICC after curative resection were still not clear, we aim to analyze the characteristics of ICC patients with coagulopathy and its correlation to prognosis. From January 2000 to June 2011, 541 ICC patients, after curative resection, were enrolled in our study. Survival curves were depicted by the Kaplan-Meier method and analyzed by the log-rank test. The Cox proportional hazard regression was adopted for multivariate survival analysis. Student's t test was performed to analyze the difference between the coagulopathy group and the normal group. The correlation between coagulation parameters and prognosis was also evaluated. The incidence rate of at least one coagulation parameter abnormality was 22.6% (122/541) while PT was the most common factor (8.87%, 48/541). The one-year survival rate of patients with coagulopathy was significantly lower than that of patients with normal coagulation (p < 0.01). In a univariate analysis, patients with prolonged PT was associated with shortened DFS (p < 0.05). Meanwhile, PT was negatively correlated with prealbumin level. TNM stage, CA19-9, GGT, and pre-albumin level were independent prognostic factors of DFS in the multivariate analysis. In conclusion, the incidence rate of coagulopathy of ICC patients is lower than HCC patients. Prolonged PT, advanced TNM stage, low prealbumin level, and high CA19-9 and GGT level were correlated with high recurrence rate and poor prognosis. [ABSTRACT FROM AUTHOR]