Multiomics analysis reveals metabolic subtypes and identifies diacylglycerol kinase α (DGKA) as a potential therapeutic target for intrahepatic cholangiocarcinoma

Background:Intrahepatic cholangiocarcinoma(iCCA)is a highly heteroge-neous and lethal hepatobiliary tumor with few therapeutic strategies.The metabolic reprogramming of tumor cells plays an essential role in the develop-ment 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 anal-ysis.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 analy-ses 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 kinaseα(DGKA)in iCCA cells.Results:Three metabolic subtypes(S1-S3)with subtype-specific biomarkers of iCCA were identified.These metabolic subtypes presented with distinct prog-noses,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 ratsar-coma 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:Viamultiomics 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.

Targeting SRSF10 might inhibit M2 macrophage polarization and potentiate anti-PD-1 therapy in hepatocellular carcinoma

Background:The efficacy of immune checkpoint blockade therapy in patients with hepatocellular carcinoma(HCC)remains poor.Although serine-and arginine-rich splicing factor(SRSF)family members play crucial roles in tumors,their impact on tumor immunology remains unclear.This study aimed to elucidate the role of SRSF10 in HCC immunotherapy.Methods:To identify the key genes associated with immunotherapy resistance,we conducted single-nuclear RNA sequencing,multiplex immunofluorescence,and The Cancer Genome Atlas and Gene Expression Omnibus database analyses.We investigated the biological functions of SRSF10 in immune evasion using in vitro co-culture systems,flow cytometry,various tumor-bearing mouse models,and patient-derived organotypic tumor spheroids.Results:SRSF10 was upregulated in various tumors and associated with poor prognosis.Moreover,SRSF10 positively regulated lactate production,and SRSF10/glycolysis/histone H3 lysine 18 lactylation(H3K18la)formed a positive feedback loop in tumor cells.Increased lactate levels promoted M2 macrophage polarization,thereby inhibiting CD8^(+)T cell activity.Mechanistically,SRSF10 interacted with the 3′-untranslated region of MYB,enhancing MYB RNA stability,and subsequently upregulating key glycolysis-related enzymes including glucose transporter 1(GLUT1),hexokinase 1(HK1),lactate dehydrogenase A(LDHA),resulting in elevated intracellular and extracellular lactate levels.Lactate accumulation induced histone lactylation,which further upregulated SRSF10 expression.Additionally,lactate produced by tumors induced lactylation of the histone H3K18la site upon transport into macrophages,thereby activating transcription and enhancing pro-tumor macrophage activity.M2 macrophages,in turn,inhibited the enrichment of CD8^(+)T cells and the proportion of interferon-γ+CD8^(+)T cells in the tumor microenvironment(TME),thus creating an immunosuppressive TME.Clinically,SRSF10 could serve as a biomarker for assessing immunotherapy resistance in various solid tumors.Pharmacological targeting of SRSF10 with a selective inhibitor 1C8 enhanced the efficacy of programmed cell death 1(PD-1)monoclonal antibodies(mAbs)in both murine and human preclinical models.Conclusions:The SRSF10/MYB/glycolysis/lactate axis is critical for triggering immune evasion and anti-PD-1 resistance.Inhibiting SRSF10 by 1C8 may overcome anti-PD-1 tolerance in HCC.