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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.

Abstract Background SQSTM1/p62 is a selective autophagy receptor that regulates multiple signaling pathways participating in the initiation and progression of tumors. Metastasis is still the main cause for intrahepatic cholangiocarcinoma (ICC)‐associated mortality. Hence, this study aimed to explore the mechanism of p62 promoting the progression of ICC. Methods Western blotting and immunohistochemical analyses were conducted to detect the expression level of protein p62 in ICC tissues and its correlation with prognosis. Subsequently, the loss‐of‐function experiments in vitro and in vivo were performed to define the role of p62 in ICC cell proliferation, invasion, and metastasis. Then, the effect of p62 knockdown on mitochondrial function and mitophagy was evaluated by measuring the oxygen consumption rate, and using immunofluorescence and western blotting analyses. Results The expression of p62 was significantly upregulated in ICC specimens compared with normal tissues. We further illustrated that p62 expression positively correlated with lymph node metastasis and poor prognosis. The loss‐of‐function assays revealed that p62 not only promoted ICC cell proliferation, migration, and invasive capacities in vitro, but also induced lung metastasis in the xenograft mouse model. Mechanistically, high expression of p62‐induced epithelial–mesenchymal transition (EMT) with the upregulation of Snail, vimentin, N‐cadherin, and downregulation of E‐cadherin. Moreover, the autophagy‐dependent function of p62 might play a vital role in maintaining the mitochondrial function of ICC by mitophagy which might further promote EMT. Conclusion These data provided new evidence for the mechanism by which abundant p62 expression promoted ICC progression, suggesting a promising therapeutic target for antimetastatic strategies in patients with ICC.

BackgroundVarious immune cell types in the tumor microenvironment (TME) of hepatocellular carcinoma (HCC) have been identified as important parameters associated with prognosis and responsiveness to immunotherapy. However, how various factors influence immune cell infiltration remains incompletely understood. Hence, we investigated the single cell multi-omics landscape of immune infiltration in HCC, particularly key gene and cell subsets that influence immune infiltration, thus potentially linking the immunotherapy response and immune cell infiltration.MethodsWe grouped patients with HCC according to immune cell infiltration scores calculated by single sample gene set enrichment analysis (ssGSEA). Differential expression analysis, functional enrichment, clinical trait association, gene mutation analysis, tumor immune dysfunction and exclusion (TIDE) and prognostic model construction were used to investigate the immune infiltration landscape through multi-omics. Stepwise regression was further used to identify key genes regulating immune infiltration. Single cell analysis was performed to explore expression patterns of candidate genes and investigate associated cellular populations. Correlation analysis, ROC analysis, Immunotherapy cohorts were used to explore and confirm the role of key gene and cellular population in predicting immune infiltration state and immunotherapy response. Immunohistochemistry and multiplexed fluorescence staining were used to further validated our results.ResultsPatients with HCC were clustered into high and low immune infiltration groups. Mutations of CTNNB1 and TTN were significantly associated with immune infiltration and altered enrichment of cell populations in the TME. TIDE analysis demonstrated that T cell dysfunction and the T cell exclusion score were elevated in the high and low infiltration groups, respectively. Six risk genes and five risk immune cell types were identified and used to construct risk scores and a nomogram model. CXCR6 and LTA, identified by stepwise regression, were highly associated with immune infiltration. Single cell analysis revealed that LTA was expressed primarily in tumor infiltrating T lymphocytes and partial B lymphocytes, whereas CXCR6 was enriched predominantly in T and NK cells. Notably, CXCR6+ CD8 T cells were characterized as tumor enriched cells that may be potential predictors of high immune infiltration and the immune-checkpoint blockade response, and may serve as therapeutic targets.ConclusionWe constructed a comprehensive single cell and multi-omics landscape of immune infiltration in HCC, and delineated key genes and cellular populations regulating immune infiltration and immunotherapy response, thus providing insights into the mechanisms of immune infiltration and future therapeutic control.

IntroductionAlthough multiple targeted treatments have appeared, hepatocellular carcinoma (HCC) is still one of the most common causes of cancer-related deaths. The immunosuppressive tumor microenvironment (TME) is a critical factor in the oncogenesis and progression of HCC. The emerging scRNA-seq makes it possible to explore the TME at a high resolution. This study was designed to reveal the immune-metabolic crosstalk between immune cells in HCC and provide novel strategies to regulate immunosuppressive TME.MethodIn this study, we performed scRNA-seq on paired tumor and peri-tumor tissues of HCC. The composition and differentiation trajectory of the immune populations in TME were portrayed. Cellphone DB was utilized to calculate interactions between the identified clusters. Besides, flow cytometry, RT-PCR and seahorse experiments were implemented to explore potential metabolic and epigenetic mechanisms of the inter-cellular interaction.ResultA total of 19 immune cell clusters were identified and 7 were found closely related to HCC prognosis. Besides, differentiation trajectories of T cells were also presented. Moreover, a new population, CD3+C1q+ tumor-associated macrophages (TAM) were identified and found significantly interacted with CD8+ CCL4+T cells. Compared to the peri-tumor tissue, their interaction was attenuated in tumor. Additionally, the dynamic presence of this newly found cluster was also verified in the peripheral blood of patients with sepsis. Furthermore, we found that CD3+C1q+TAM affected T cell immunity through C1q signaling-induced metabolic and epigenetic reprogramming, thereby potentially affecting tumor prognosis.ConclusionOur study revealed the interaction between CD3+C1q+TAM and CD8+ CCL4+T cells and may provide implications for tackling the immunosuppressive TME in HCC.

As cancer is increasingly considered a metabolic disorder, it is postulated that serum metabolite profiling can be a viable approach for detecting the presence of cancer. Here, the authors report a machine learning model using mass spectrometry-based liquid biopsy data for pan-cancer screening and classification.

Desmoplasia is a hallmark of intrahepatic cholangiocarcinoma (ICC), which constitutes a barrier to infiltration of lymphocyte, but not myeloid cells. Given that dense desmoplastic stroma has been reported to be a barrier to infiltration of lymphocyte, but not myeloid cells. We here investigated whether fibroblastic FAP influenced ICC progression via non-T cell-related immune mechanisms. We demonstrated fibroblastic FAP expression was critical for STAT3 activation and CCL2 production, and ICC-CAFs were the primary source of CCL2 in human ICC microenvironment by using ICC-Fbs from six ICC patients. Fibroblastic knockdown of FAP significantly impaired the ability of ICC-CAFs to promote ICC growth, MDSCs infiltration and angiogenesis, which was restored by adding exogenous CCL2. Furthermore, interestingly, the tumor-promoting effect of fibroblastic FAP is dependent on MDSCs via secretion of CCL2, as depletion of Gr-1+ cells reversed the restoring effects of exogenous CCL2 on tumor growth and angiogenesis. In vitro migration assay confirmed that exogenous CCL2 could rescue the impaired ability of ICC-Fbs to attract Gr-1+ cells caused by fibroblastic FAP knockdown. In contrast, fibroblastic FAP knockdown had no effect on ICC cell proliferation and apoptotic resistance. Depletion MDSCs by anti-Gr-1 monoclonal antibody in subcutaneous transplanted tumor model abrogated tumor promotion by ICC-CAFs suggested that the pro-tumor function of Fibroblastic FAP relied on MDSCs. Mechanical, flow cytometry and chamber migration assay were conducted to find Fibroblastic FAP was required by the ability of ICC-CAFs to promote MDSC migration directly. Moreover, fibroblastic FAP knockdown had no effect on cell proliferation and apoptotic resistance. Here, we revealed the T-cell independent mechanisms underlying the ICC-promoting effect of fibroblastic FAP by attracting MDSCs via CCL2, which was mainly attributed to the ability of FAP to attract MDSCs and suggests that specific targeting fibroblastic FAP may represent a promising therapeutic strategy against ICC.

Background Regulating T-cell metabolism is crucial for their anticancer activity. Therefore, understanding the function and metabolism of human tumor-infiltrating T cells is of broad interest and clinical importance.Methods CD3+CD45+ T cells were sorted from adjacent area or tumor core of human hepatocellular carcinoma (HCC), then the clusters and heterogeneity of T cells were further interrogated by single-cell transcriptomic profiling. 118 surgical samples from patients with HCC were histologically examined for infiltration of CD8+ T cells in tumor and adjacent tissue.Results Single-cell transcriptomic profiling indicated that several exhausted T-cell (Tex) populations differentially coexisted in the tumor and adjacent tissue. CD137 identifies and enriches Tex with superior effector functions and proliferation capacity. Furthermore, enhanced fatty acid-binding protein 5 (FABP5) expression along with increased mitochondrial oxidative metabolism were evident in these CD137-enriched Tex. Inhibiting FABP5 expression and mitochondrial fatty acid oxidation impaired the anti-apoptosis and proliferation of CD137-enriched Tex. These observations have been verified by generating CD137 CART. Immunohistochemistry staining on the tissue microarray of 118 patients with HCC showed intra-tumoral FABP5 high CD8+ T-cell infiltration was linked to overall and recurrence-free survival.Conclusions The tumor microenvironment can impose metabolic restrictions on T-cell function. CD137, a costimulatory molecule highly expressed on some Tex, uses exogenous fatty acids and oxidative metabolism to mediate antitumor immunity. The immunometabolic marker FABP5 should be investigated in larger, longitudinal studies to determine their potential as prognostic biomarkers for HCC.

Abstract Background Exhausted T cells and regulatory T cells (Tregs) comprise diverse subsets of tumor immunosuppressive microenvironment that play key roles in tumor progress. Understanding subset diversity in T cells is a critical question for developing cancer immunotherapy. Methods A total of 235 specimens from surgical resections of hepatocellular carcinoma (HCC) patients were examined for infiltration of exhausted T cell (Tex) in tumor and adjacent tissue. We conducted deep single‐cell targeted immune profiling on CD3+ cells collected from tumor tissues, adjacent normal tissues (ANTs) and peripheral blood of HCC patients. Total 10 cell clusters were identified with distinct distributions and characteristics. Results We observed transitional differentiation of exhausted CD8+T cells and Tregs increasingly enriched in tumor tissue. The accumulation and location of Tex were related to the differences in the long‐term clinical outcome of HCC. Furthermore, data of single‐cell RNA‐seq showed that (1) cells transforming from effector CD8+ T cells to exhausted CD8+ T cells simultaneously expressed upregulated effector molecules and inhibitory receptors, (2) indicated alteration of gene expression related to stress response and cell cycle at early exhaustion stage, and (3) immunosuppressive Treg had profound activation in comparison to resting Tregs. Conclusions T cell exhaustion is a progressive process, and the gene‐expression profiling displayed T cell exhaustion and anergy are different. Accordingly, it is possible that functional exhaustion is caused by the combination effects of passive defects and overactivation in stress response. The results help to understand the dynamic framework of T cells function in cancer which is important for designing rational cancer immunotherapies.

Despite the success of monotherapies based on blockade of programmed cell death 1 (PD-1) in human melanoma, most patients do not experience durable clinical benefit. T-cell infiltration and/or the presence of PD-L1 in tumors may be used as indicators of clinical response; However, recent studies reported that preexisting tumor-specific T cells may have limited reinvigoration capacity. Therefore, evaluating status of T cells of tumor-adjacent area and its impact on the prognosis are very important. Here, we examined 117 surgical samples from HCC patients for infiltration of exhausted T cell (Tex) including CD4+-Tex, CD8+-Tex and regulatory T cell (FOXP3+-Treg) in tumor and adjacent tissue. CD3+CD45RO+T cells were sorted from adjacent area or tumor core, then the clusters and heterogeneity of T cells were further interrogated by single-cell RNA sequencing. As a result, we suggested that abundance or location of T cell subsets is differentially correlate with long-term clinical outcome of HCC. In contrast with CD4+T or CD4+-Tex, the infiltration of CD8+T or CD8+-Tex cells was closely linked to overall or recurrence-free survival. FOXP3+-Treg is more predictive of early recurrence. Single-cell transcriptional analysis demonstrates the composition of CD4+-Tex, CD8+-Tex, and FOXP3+-Treg is shifted in tumor and adjacent tissue. Molecular profiles including genes coding checkpoint receptors, effector molecules are distinct between CD4+-Tex, CD8+-Tex, though some common features of CD4+ and CD8+ T cell exhaustion are revealed. In conclusion, we underline the heterogeneity and clinical relevance of Tex cells in HCC patients. A better understanding of Tex is critical for HCC monitoring and treatment.

Background: Various immune cell types in the tumor microenvironment (TME) of hepatocellular carcinoma (HCC) have been identified as important parameters associated with prognosis and responsiveness to immunotherapy. However, how various factors influence immune cell infiltration remains incompletely understood. Hence, we investigated the single cell multi-omics landscape of immune infiltration in HCC, particularly key gene and cell subsets that influence immune infiltration, thus potentially linking the immunotherapy response and immune cell infiltration. Methods: We grouped patients with HCC according to immune cell infiltration scores calculated by single sample gene set enrichment analysis (ssGSEA). Differential expression analysis, functional enrichment, clinical trait association, gene mutation analysis, tumor immune dysfunction and exclusion (TIDE) and prognostic model construction were used to investigate the immune infiltration landscape through multi-omics. Stepwise regression was further used to identify key genes regulating immune infiltration. Single cell analysis was performed to explore expression patterns of candidate genes and investigate associated cellular populations. Correlation analysis, ROC analysis, Immunotherapy cohorts were used to explore and confirm the role of key gene and cellular population in predicting immune infiltration state and immunotherapy response. Immunohistochemistry and multiplexed fluorescence staining were used to further validated our results. Results: Patients with HCC were clustered into high and low immune infiltration groups. Mutations of CTNNB1 and TTN were significantly associated with immune infiltration and altered enrichment of cell populations in the TME. TIDE analysis demonstrated that T cell dysfunction and the T cell exclusion score were elevated in the high and low infiltration groups, respectively. Six risk genes and five risk immune cell types were identified and used to construct risk scores and a nomogram model. CXCR6 and LTA, identified by stepwise regression, were highly associated with immune infiltration. Single cell analysis revealed that LTA was expressed primarily in tumor infiltrating T lymphocytes and partial B lymphocytes, whereas CXCR6 was enriched predominantly in T and NK cells. Notably, CXCR6+ CD8 T cells were characterized as tumor enriched cells that may be potential predictors of high immune infiltration and the immunecheckpoint blockade response, and may serve as therapeutic targets. Conclusion: We constructed a comprehensive single cell and multi-omics landscape of immune infiltration in HCC, and delineated key genes and cellular populations regulating immune infiltration and immunotherapy response, thus providing insights into the mechanisms of immune infiltration and future therapeutic control. [ABSTRACT FROM AUTHOR]

Production of TGF-b by T cells is key to various aspects of immune homeostasis, with defects in this process causing or aggravating immune-mediated disorders. The molecular mechanisms that lead to TGF-b generation by T cells remain largely unknown. To address this issue, we take advantage of the fact that intestinal helminths stimulate Th2 cells besides triggering TGF-b generation by T lymphocytes and regulate immune-mediated disorders. We show that the Th2 cell-inducing transcription factor STAT6 is necessary and sufficient for the expression of TGF-b propeptide in T cells. STAT6 is also necessary for several helminth-triggered events in mice, such as TGF-b-dependent suppression of alloreactive inflammation in graft-versus-host disease. Besides STAT6, helminth-induced secretion of active TGF-b requires cleavage of propeptide by the endopeptidase furin. Thus, for the immune regulatory pathway necessary for TGF-b production by T cells, our results support a two-step model, composed of STAT6 and furin. [ABSTRACT FROM AUTHOR]

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]

Helminths stimulate the secretion of Th2 cytokines, like IL-4, and suppress lethal graft-versus-host disease (GVHD) after bone marrow transplantation. This suppression depends on the production of immune-modulatory TGF-b and is associated with TGF-b-dependent in vivo expansion of Foxp3+ regulatory T cells (Treg). In vivo expansion of Tregs is under investigation for its potential as a therapy for GVHD. Nonetheless, the mechanism of induced and TGF-b-dependent in vivo expansion of Tregs, in a Th2 polarized environment after helminth infection, is unknown. In this study, we show that helminth-induced IL-4 production by host cells is critical to the induction and maintenance of TGF-b secretion, TGF-b-dependent expansion of Foxp3+ Tregs, and the suppression of GVHD. In mice with GVHD, the expanding donor Tregs express the Th2-driving transcription factor, GATA3, which is required for helminth-induced production of IL-4 and TGF-b. In contrast, TGF-b is not necessary for GATA3 expression by Foxp3+ Tregs or by Foxp32 CD4 T cells. Various cell types of innate or adaptive immune compartments produce high quantities of IL-4 after helminth infection. As a result, IL-4-mediated suppression of GVHD does not require invariant NKT cells of the host, a cell type known to produce IL-4 and suppress GVHD in other models. Thus, TGF-b generation, in a manner dependent on IL-4 secretion by host cells and GATA3 expression, constitutes a critical effector arm of helminthic immune modulation that promotes the in vivo expansion of Tregs and suppresses GVHD. [ABSTRACT FROM AUTHOR]