Tumor Microenvironment Of Hepatocellular Carcinoma Research Articles

Impact of anesthesia-related genes on prognosis and tumor microenvironment in hepatocellular carcinoma: A comprehensive analysis.

Hepatocellular carcinoma (HCC), renowned for its bleak prognosis and high recurrence rates, necessitates innovative strategies for prognosis assessment and therapeutic intervention. In this pursuit, we systematically investigated the influence of anesthesia-related genes (ANARGs) on HCC outcomes. Leveraging data from The Cancer Genome Atlas (TCGA), our study scrutinized RNA sequencing data and clinical profiles from 374 HCC patients alongside 50 non-tumor liver samples to unravel ANARG expression patterns and their clinical relevance. Employing consensus clustering, we segregated HCC samples into two distinct subtypes based on ANARG profiles, unveiling significant survival disparities between them. Further differential expression analysis pinpointed pivotal genes and pathways distinguishing these subtypes, notably implicating lipid metabolism and the MTOR signaling pathway in HCC pathogenesis. A prognostic model, comprising five key ANARGs (DAGLA, CYP26B, HAVCR, G6PD and AKR1B), exhibited robust predictive capability for patient outcomes, validated across independent patient cohorts. Furthermore, immune infiltration analysis uncovered a nuanced interplay between ANARG expression and the tumor immune microenvironment, spotlighting variations in immune cell infiltration and function across the identified HCC subtypes. This comprehensive analysis underscores not only the prognostic significance of ANARGs in HCC but also their potential to modulate the tumor microenvironment, providing novel insights for tailoring anesthetic management and therapeutic strategies in HCC care. Our findings advocate for a more integrative approach to HCC management, amalgamating molecular profiling with traditional clinical parameters to refine patient stratification and personalize treatment strategies.

Multifaceted roles of lymphatic and blood endothelial cells in the tumor microenvironment of hepatocellular carcinoma: A comprehensive review.

The tumor microenvironment is a complex network of cells, extracellular matrix, and signaling molecules that plays a critical role in tumor progression and metastasis. Lymphatic and blood vessels are major routes for solid tumor metastasis and essential parts of tumor drainage conduits. However, recent studies have shown that lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) also play multifaceted roles in the tumor microenvironment beyond their structural functions, particularly in hepatocellular carcinoma (HCC). This comprehensive review summarizes the diverse roles played by LECs and BECs in HCC, including their involvement in angiogenesis, immune modulation, lymphangiogenesis, and metastasis. By providing a detailed account of the complex interplay between LECs, BECs, and tumor cells, this review aims to shed light on future research directions regarding the immune regulatory function of LECs and potential therapeutic targets for HCC.

DNA methylation regulator-based molecular subtyping and tumor microenvironment characterization in hepatocellular carcinoma.

Although recent studies have reported the regulation of the immune response in hepatocellular carcinoma (HCC) through DNA methylation, the comprehensive impact methylation modifications on tumor microenvironment characteristics and immunotherapy efficacy has not been fully elucidated. In this research, we conducted a comprehensive assessment of the patterns of DNA methylation regulators and the profiles of the tumor microenvironment (TME) in HCC, focusing on 21 specific DNA methylation regulators. We subsequently developed a unique scoring system, a DNA methylation score (DMscore), to assess the individual DNA methylation modifications among the three distinct methylation patterns for differentially expressed genes (DEGs). Three distinct methylation modification patterns were identified with distinct TME infiltration characteristics. We demonstrated that the DMscore could predict patient subtype, TME infiltration, and patient prognosis. A low DMscore, characterized by an elevated tumor mutation burden (TMB), hepatitis B virus (HBV)/hepatitis C virus (HCV) infection, and immune activation, indicates an inflamed tumor microenvironment phenotype with a 5-year survival rate of 7.8%. Moreover, a low DMscore appeared to increase the efficacy of immunotherapy in the anti-CTLA-4/PD-1/PD-L1 cohort. In brief, this research has enhanced our understanding of the correlation between modifications in DNA methylation patterns and the profile of the tumor microenvironment in individuals diagnosed with HCC. The DMscore may serve as an alternative biomarker for survival and efficacy of immunotherapy in patients with HCC.

An exosome mRNA-related gene risk model to evaluate the tumor microenvironment and predict prognosis in hepatocellular carcinoma

BackgroundThe interplay between exosomes and the tumor microenvironment (TME) remains unclear. We investigated the influence of exosomes on the TME in hepatocellular carcinoma (HCC), focusing on their mRNA expression profile.MethodsmRNA expression profiles of exosomes were obtained from exoRBase. RNA sequencing data from HCC patients’ tumors were acquired from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC). An exosome mRNA-related risk score model of prognostic value was established. The patients in the two databases were divided into high- and low-risk groups based on the median risk score value, and used to validate one another. Functional enrichment analysis was performed based on a differential gene prognosis model (DGPM). CIBERSORT was used to assess the abundance of immune cells in the TME. The correlation between the expression levels of immune checkpoint-related genes and DGPM was analyzed alongside the prediction value to drug sensitivity.ResultsA prognostic exosome mRNA-related 4-gene signature (DYNC1H1, PRKDC, CCDC88A, and ADAMTS5) was constructed and validated. A prognostic nomogram had prognostic ability for HCC. The genes for this model are involved in extracellular matrix, extracellular matrix (ECM)-receptor interaction, and the PI3K-Akt signaling pathway. Expression of genes here had a positive correlation with immune cell infiltration in the TME.ConclusionsOur study results demonstrate that an exosome mRNA-related risk model can be established in HCC, highlighting the functional significance of the molecules in prognosis and risk stratification.

The role of alpha-fetoprotein in the tumor microenvironment of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a prevalent malignant cancer worldwide, characterized by high morbidity and mortality rates. Alpha-fetoprotein (AFP) is a glycoprotein synthesized by the liver and yolk sac during fetal development. However, the serum levels of AFP exhibit a significant correlation with the onset and progression of HCC in adults. Extensive research has demonstrated that the tumor microenvironment (TME) plays a crucial role in the malignant transformation of HCC, and AFP is a key factor in the TME, promoting HCC development. The objective of this review was to analyze the existing knowledge regarding the role of AFP in the TME. Specifically, this review focused on the effect of AFP on various cells in the TME, tumor immune evasion, and clinical application of AFP in the diagnosis and treatment of HCC. These findings offer valuable insights into the clinical treatment of HCC.

Metabolome Profiling of Malignant Ascites Identifies Candidate Metabolic Biomarkers of Hepatocellular Carcinoma.

Malignant ascites is one of the severe complications of hepatocellular carcinoma, which can be regarded as a unique tumor microenvironment of hepatocellular carcinoma. The identification of novel biomarkers in malignant ascites could be crucial to differentiate patients with hepatocellular carcinoma and cirrhotic ascites. The study aimed to distinguish the metabolomics of malignant ascites in patients with hepatocellular carcinoma from that of non-malignant ascites (cirrhotic ascites). Liquid chromatography-mass spectrometry was performed to analyze the differentially distributed biomarkers in patients with malignant ascites and hepatocellular carcinoma (n = 39), as well as in patients with cirrhotic ascites, which were taken as controls (n = 36). A total of 20 differential metabolites associated with malignant ascites were identified, of which 8 metabolites were upregulated and 12 metabolites were downregulated (ratio < 0.5 or > 1.5, respectively). Moreover, pathway and enrichment analyses revealed nitrogen metabolism, urea cycle, phenylalanine, and tyrosine metabolism to be implicated in the formation of malignant ascites in patients with hepatocellular carcinoma. Our results suggest that the key factors associated with pathways, such as arachidonic acid, phenylalanine, and glutamic acid pathways, are potential ascitic fluidbased biomarkers for differentiating hepatocellular carcinoma with cirrhosis ascites; the results also provide a clinical pathophysiological interpretation of biomarkers and metabolic pathways relevant to disease status.

Identification of key molecules in the formation of portal vein tumor thrombus in hepatocellular carcinoma based on single cell transcriptomics and in vitro experiments.

The presence of portal vein tumor thrombus (PVTT) is a significant indicator of advanced-stage hepatocellular carcinoma (HCC). Unfortunately, the prediction of PVTT occurrence remains challenging, and there is a lack of comprehensive research exploring the underlying mechanisms of PVTT formation and its association with immune infiltration. Our approach involved analyzing single-cell sequencing data, applying high dimensional weighted gene co-expression network analysis (hdWGCNA), and identifying key genes associated with PVTT development. Furthermore, we constructed competing endogenous RNA (ceRNA) networks and employed weighted gene co-expression network analysis (WGCNA), as well as three machine-learning techniques, to identify the upstream regulatory microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) of the crucial mRNAs. We employed fuzzy clustering of time series gene expression data (Mfuzz), gene set variation analysis (GSVA), and cell communication analysis to uncover significant signaling pathways involved in the activation of these important mRNAs during PVTT development. In addition, we conducted immune infiltration analysis, survival typing, and drug sensitivity analysis using The Cancer Genome Atlas (TCGA) cohort to gain insights into the two patient groups under study. Through the implementation of hdWGCNA, we identified 110 genes that was closely associated with PVTT. Among these genes, TMEM165 emerged as a crucial candidate, and we further investigated its significance using COX regression analysis. Furthermore, through machine learning techniques and survival analysis, we successfully identified the upstream regulatory miRNA (hsa-miR-148a) and lncRNA (LINC00909) that targeted TMEM165. These findings shed light on the complex regulatory network surrounding TMEM165 in the context of PVTT. Moreover, we conducted CIBERSORT analysis, which unveiled correlations between TMEM165 and immune infiltration in HCC patients. Specifically, TMEM165 exhibited associations with various immune cell populations, including memory B cells and CD8+ T cells. Additionally, we observed implications for immune function, particularly in relation to immune checkpoints, within the context of HCC. The regulatory axis involving TMEM165, hsa-miR-148a, and LINC00909 emerges as a crucial determinant in the development of PVTT in HCC patients, and it holds significant implications for prognosis. Furthermore, alterations in the TMEM165/hsa-miR-148a/LINC00909 regulatory axis exhibit a strong correlation with immune infiltration within the HCC tumor microenvironment, leading to immune dysfunction and potential failure of immunotherapy.

Hepatocellular carcinoma immune microenvironment and check point inhibitors-current status.

Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and has a high mortality rate. The Barcelona Clinic Liver Cancer staging system in addition to tumor staging also links the modality of treatment available to a particular stage. The recent description of the tumor microenvironment (TME) in HCC has provided a new concept of immunogenicity within the HCC. Virus-related HCC has been shown to be more immunogenic with higher expression of cytotoxic T lymphocytes and decreased elements for immunosuppression such as regulatory T cells. This immunogenic milieu provides a better response to immunotherapy especially immune checkpoint inhibitors (ICIs). In addition, the recent data on combining locoregional therapies and other strategies may convert the less immunogenic state of the TME towards higher immunogenicity. Therefore, data are emerging on the use of combinations of locoregional therapy and ICIs in unresectable or advanced HCC and has shown better survival outcomes in this difficult population.

Single-cell and spatial analyses revealed the co-location of cancer stem cells and SPP1+ macrophage in hypoxic region that determines the poor prognosis in hepatocellular carcinoma

In hepatocellular carcinoma (HCC), classical cancer stem cells (CSC) markers were shared by normal stem cells, targeting which may hinder hepatic regeneration and cause liver failure. Additionally, the spatial structure of CSC still remained elusive. To address these limitations, we undertook a comprehensive study combining single-cell data (56,022 cells from 20 samples) and spatial data (38,191 spots from eight samples) to obtain CSC signature and uncover its spatial structure. Utilizing the CytoTRACE algorithm, we discretely identified CSC, which displayed upregulated proliferation pathways regulated by HIF1A. A CSC signature of 107 genes was then developed using Weighted Gene Co-expression Network Analysis (WGCNA). Notably, HCC patients with high CSC levels exhibited an accumulation of SPP1+ macrophages (Macro_SPP1) expressing metalloproteinases (MMP9, MMP12, and MMP7) regulated by HIF1A, suggesting a hypoxic tumor region connecting Macro_SPP1 and CSC. Both CSC and Macro_SPP1 correlated with worse prognosis and undesirable immunotherapy response. Spatial analysis revealed the co-location of CSC and Macro_SPP1, with CD8 T cells excluded from the tumor region. The co-location area and non-tumor area of boundary exhibited a high level of hypoxia, with the HAVRC2 checkpoint highly expressed. Within the co-location area, the SPP1 signaling pathway was most active in cell-cell communication, with SPP1-CD44 and SPP1-ITGA/ITGB identified as the main ligand-receptor pairs. This study successfully constructed a CSC signature and demonstrated the co-location of CSC and Macro_SPP1 in a hypoxic region that exacerbates the tumor microenvironment in HCC.

Abstract 7398: Unveiling the tumor microenvironment of hepatocellular carcinoma using AI trained by spatial transcriptomics: A preliminary study to predict response to immunotherapy

Abstract Background. Immune checkpoint inhibitors (ICIs), particularly targeting the PD-1 pathway, are promising in treating hepatocellular carcinoma (HCC). However, their variable effectiveness among individuals calls for a better understanding of the tumor microenvironment (TME) and reliable predictive biomarkers. Here, we employ spatial transcriptomics (ST) to develop a deep-learning model that aims to investigate the TME in HCC using Hematoxylin and eosin (H&amp;E) staining images. Our focus is on identifying cell types within the TME that are linked to the response to ICI in a cohort of patients treated with nivolumab. Methods. Our study leveraged 21 Visium ST datasets from HCC to develop a model aimed at inferring the cellular composition of TME from H&amp;E images that matched with ST data. The comprehensive TME cell types enrichment score, encompassing Tumor Endothelial Cells (TECs), Tumor-Associated Macrophages (TAMs), B cells, T cells, and Cancer-Associated Fibroblasts (CAFs) in each spot, was calculated by the CellDART algorithm, a method that maps cell type by integrating with a reference scRNA-seq data. The model was trained in a patch-wise manner, utilizing a pre-trained ResNetRS50 as the backbone model. For the internal validation, Spearman correlation coefficients were evaluated for predicted cell types using H&amp;E, and the trained model was correlated with cell type enrichment scores estimated by ST datasets of 4 samples independent of the training set. The model was applied to H&amp;E images of 16 patients with HCC who underwent nivolumab treatment. The model predicted the 5 cell types enrichment score in the tumor and tumor-adjacent normal liver tissues. Results. The internal validation set results demonstrate robust Spearman correlations between our model predictions and actual cellular compositions in the TME. Specifically, we observe strong correlations for T cells (rho = 0.66), TAMs (rho=0.46), CAFs (rho=0.32), B cells (rho=0.30), and TECs (rho=0.24). When we applied the model to the H&amp;E images of the cohort of patients who underwent nivolumab, immunotherapy non-responders showed a significantly higher predicted enrichment score of CAFs in tumor-adjacent regions (Mann-Whitney test, p&amp;lt;.01). Upon stratifying patients based on stromal CAF prediction, those with low stromal CAF levels exhibited better overall survival (Log-rank test, p&amp;lt;.05). Conclusions. We present a deep learning model to analyze TME in HCC solely on H&amp;E images trained by ST data. Our findings showed a potential relationship between CAFs in tumor-adjacent regions and non-responders to nivolumab treatment in HCC. These insights underscore the potential to predict nivolumab treatment responders using H&amp;E images combined with the deep learning model. This approach could provide a significant advancement in personalized treatment strategies for HCC patients. Citation Format: Dongjoo Lee, Haenara Shin, Seungho Cook, Daeseung Lee, Hongyoon Choi, Won-Mook Choi, Changhoon Yoo, Kwon Joong Na. Unveiling the tumor microenvironment of hepatocellular carcinoma using AI trained by spatial transcriptomics: A preliminary study to predict response to immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7398.

Abstract 1408: Intrahepatic IgA complex induces polarization of cancer-associated fibroblasts to matrix phenotypes in the tumor microenvironment of HCC

Abstract Background and Aims: Cancer-associated fibroblasts (CAFs) are activated fibroblasts that play key roles in the tumor microenvironment (TME). Immunoglobulin A (IgA) contributes to inflammation and anti-tumor immunity dismantling in the human liver. We investigated the effects of the IgA complex on CAFs in the TME of hepatocellular carcinoma (HCC). Approach and Results: CAF dynamics in HCC TME were analyzed via single-cell RNA sequencing of HCC samples. CAFs were isolated from 40 HCC samples. The isolated CAFs were treated with mock or serum-derived IgA dimers. Following treatment with the mock or serum IgA dimers in vitro, co-culture experiments were performed using CAF and CD8+ T cells. Single-cell analysis showed that sub-cluster proportions in the CAF-fibroblast activation protein-α (FAP) matrix were significantly increased in patients with high serum IgA levels. We were performed flow cytometry on fresh surgical tissues and observed a significant increase in the mean fluorescence intensity (MFI) of FAP in the CD68+ cells from patients with high serum IgA levels compared to those with low serum IgA levels (p&amp;lt;0.001). We validated that the transferrin receptor (CD71) is expressed in CAFs (p&amp;lt;0.01). IgA-treated CAFs exhibited higher programmed death-ligand 1 (PD-L1) expression levels than mock-treated CAFs (p&amp;lt;0.05). Co-culture with CAFs induced the attenuation of the cytotoxic function of activated CD8+ T cell, and these cells co-cultured with IgA-treated CAFs exhibited increased expression levels of programmed death-1 (PD-1) compared to those co-cultured with mock-treated CAFs (p&amp;lt;0.05). Conclusions: Intrahepatic IgA induces polarization of HCC CAFs into more malignant matrix phenotype and attenuates cytotoxic T cell function. Our study uncovers five dynamic CAF subpopulations within HCC tissues and highlights their potential roles in tumor progression and immune suppression. Citation Format: Pil Soo Sung. Intrahepatic IgA complex induces polarization of cancer-associated fibroblasts to matrix phenotypes in the tumor microenvironment of HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1408.

Abstract 1526: The distinct tumor microenvironment of advanced hepatocellular carcinoma with high PVR or high PD-L1 expression

Abstract Background: The combination of anti-PD-L1 and anti-VEGF has been the standard-of-care for advanced hepatocellular carcinoma (HCC), while additionally targeting TIGIT is under active investigation. We aimed to explore the expression and clinical significance of PVR (CD155), the ligand of TIGIT, within the tumor microenvironment (TME) of advanced HCC. Methods: All HCC tumor specimens were obtained at the advanced stage of HCC. Immunohistochemistry (IHC) was employed to evaluate membranous staining of PVR and PD-L1 of tumor specimens, and semiquantitative scores with IHC 0, 1, 2, or 3 were given if &amp;lt; 1%, ≥1% but &amp;lt; 5%, ≥5% but &amp;lt; 10%, or ≥10% of tumor cells (TCs) and tumor-infiltrating immune cells (ICs) were PVR or PD-L1 positive. Selected tumor specimens underwent immune gene expression profiling using the nCounter Analysis System (NanoString Technologies, Inc.) with the PanCancer Immune Profiling Panel. Results: The study enrolled 67 advanced HCC patients, with median age of 59.2 years (male:female = 57:10). Forty-eight (71.6%) of the patients were hepatitis B virus (HBV) surface antigen positive, and 23 (34.3%) had received sorafenib before the study. Thirteen (19.4%) and 18 (26.9%) tumor tissues showed positive PVR expressions (IHC scores ≥1) in TCs and ICs, respectively; Seventeen (25.4%) and 36 (53.7%) tumor tissues showed positive PD-L1 expressions in TCs and ICs, respectively. The expressions of PVR in TCs or ICs showed no association with clinical factors, such as sex, age, HBV infection, sorafenib treatment, or overall survival. Interestingly, in both TCs and ICs, the intensities of PVR and PD-L1 expression were inversely correlated for those with at least IHC scores ≥1 in either PVR or PD-L1 (TCs, n = 26, r = -0.6966, p &amp;lt; 0.0001; ICs, n = 46, r = -0.4548, p = 0.0015). Immune profiling of the selected tumor specimens showed that those with high PVR but low PD-L1 expressions had significantly lower CD8 T cells scores, lower cytotoxic cells scores, and lower CD8/Treg ratio than those with high PD-L1 but low PVR expressions. Conclusions: There was an inverse correlation observed between expressions of PVR and PD-L1 in the advanced HCC tissues. The TME of those with high PVR expression was distinct from those with high PD-L1 expression. These findings may have important clinical implications for developing combination immunotherapy in advanced HCC. (This work is supported by grants from the Ministry of Science and Technology, Taiwan, MOST 110-2314-B-002-204-MY3). Citation Format: Li-Chun Lu, Yi-Hsuan Lee, Tsung-hao Liu, Yu-Yun Shao, Ann-Lii Cheng, Chih-Hung Hsu. The distinct tumor microenvironment of advanced hepatocellular carcinoma with high PVR or high PD-L1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1526.

Abstract 6524: Single-cell landscape of cancer-associated fibroblasts in immunotherapy resistance of hepatocellular carcinoma

Abstract Introduction: The advent of immune checkpoint blockade (ICB) therapy has revolutionized the treatment approach for hepatocellular carcinoma (HCC). However, the response rate to ICB therapy remains low (below 20%). This limited response rate can be attributed to the considerable heterogeneity observed in HCC cells and the tumor microenvironment (TME). Recent research has highlighted the pivotal role of cancer-associated fibroblasts (CAFs) in orchestrating various components within the TME of HCC. Although the significance of lipid metabolism-associated CAFs in the efficacy of ICB therapy has been demonstrated in HCC murine models [1], the functions and contributions of other CAF subtypes remain largely unknown. Therefore, identifying CAF heterogeneity could advance our comprehension of HCC TME and potentially augment ICB efficacy. Methods: We performed single-cell RNA sequencing on tumor biopsy specimens obtained from patients with advanced HBV-related HCC who had participated in a pembrolizumab (anti-PD1) phase II clinical trial (NCT03419481). Our objective was to examine the dynamic alterations in the HCC TME before and during anti-PD1 treatment (upon 2-cycle). We utilized the Seurat and Cellchat packages for bioinformatics analysis which enabled us to investigate the associations between changes in the proportions of CAF subtypes and the patients' clinical responses, as well as the potential cell-cell interactions involving CAF and other TME components. Results: We identified four CAF subtypes within the TME: cycling, inflammatory, matrix, and vascular CAFs in our anti-PD1 HCC patient cohort. Among the anti-PD1 non-responders, there was a significant increase in the proportions of cycling CAFs (cCAFs) and matrix CAFs (matCAFs) compared to the responders. Notably, matCAFs exhibited a high enrichment of Gene Ontology (GO) Terms related to the extracellular matrix (ECM), whose higher proportion correlated with poor prognosis of patients. Moreover, a distinct collagen pathway signal was found between matCAFs and two immunosuppressive cell types, namely regulatory T cells and M2 macrophages in the non-responders. Discussion and Conclusion: The presence of matCAFs within the HCC tumor may associate with the development of an immunosuppressive TME and unfavorable prognosis for patients. Targeting this specific CAF subtype holds promise as a potential strategy to overcome resistance to ICB therapy. Acknowledgments: The CUHK Strategic Seed Funding for Collaborative Research Scheme and The Li Ka Shing Foundation.

Abstract 6755: NKT activation enhanced the therapeutic efficacy of neoantigen vaccine in hepatocellular carcinoma

Abstract One sentence introduction: This study indicated the potential of combinational therapy of neoantigen vaccine and iNKT activator α-GalCer in Hepatocellular carcinoma. Hepatocellular carcinoma (HCC) is a leading cause of death around the world. Current immune checkpoint blockade therapies only show effectiveness in some cancer patients, so there is an urgent need for more effective immunotherapy strategies. One alternative is the use of neoantigen-based cancer vaccines, which target tumor-specific antigens (neoantigens) on cancer cells and induce strong T-cell responses. Advances in technology now allow for precise identification of tumor neoantigens using bioinformatic analysis or mass spectrometry. While cancer vaccines have demonstrated strong anti-tumor immune responses and therapeutic effectiveness in some cancer types, their success in HCC remains limited. A contributing factor is the suppressive tumor microenvironment (TME) found in advanced HCC. Some studies suggest that combining neoantigen vaccines with anti-PD1/PD-L1 therapies can significantly enhance HCC treatment outcomes. Overcoming the suppressive immune microenvironment is crucial in cancer treatment, and reactivating intratumoral immunity is essential. In our study, we developed an HCC cancer vaccine using transcriptome sequencing and bioinformatics analysis. Our ELISpot assay results showed that this vaccine induced strong tumor-specific immune responses and significantly inhibited tumor growth in early-stage orthotopic HCC mouse models when administered five days after tumor inoculation. However, the effectiveness decreased in advanced tumors when administered ten days after tumor inoculation. We also discovered a significant relationship between the therapeutic effectiveness of the neoantigen vaccine and the activation of intratumoral NKT cells in HCC. Our study suggested that the type-I NKT cell activator, α-Galactosylceramide (α-GalCer), significantly improved the therapeutic outcomes of the cancer neoantigen vaccine in advanced orthotopic HCC mouse models. In some cases, tumors were almost completely eliminated. This indicates the potential of combining iNKT activators with neoantigen vaccines for HCC treatment. To further understand the role of NKT cells in HCC's TME, we plan to investigate intratumoral NKT cell subtypes following neoantigen vaccine therapy. Additionally, we will develop a new delivery system to deliver type I NKT cell activators and type II NKT inhibitors to tumor sites, aiming to reactivate the suppressive TME in HCC after neoantigen vaccine therapy. Citation Format: Renhao Li, Jing-Chu Hu, Li Rong, Yangfan Wu, Yige He, Jiandong Huang. NKT activation enhanced the therapeutic efficacy of neoantigen vaccine in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6755.

Abstract 7039: Leveraging single cell RNA-seq for uncovering immune landscape of hepatocellular carcinoma

Abstract The immune cell types as well as tumor microenvironment (TME) status may influence prognosis, metastasis, tumor progression, and clinical response to immunotherapies for cancer. Hepatocellular carcinoma (HCC) is a typical highly heterogeneous solid tumor with high morbidity and mortality worldwide, especially in China, however, the immune microenvironment of HCC, especially which caused by cancerogenic substance has not been clarified so far. In this study, we employed single-cell RNA sequencing (scRNA-seq) on diethylnitrosamine (DEN)-induced mouse HCC model to dissect the immune cell dynamics during tumorigenesis. Our findings reveal distinct immune profiles in both precancerous and cancerous lesions, indicating early tumor-associated immunological alterations. Notably, specific T and B cell subpopulations are preferentially enriched in the HCC TME. Furthermore, we identified a subpopulation of naïve B cells with high CD83 expression, correlating with improved prognosis in human HCC. These signature genes were validated in The Cancer Genome Atlas (TCGA) HCC RNA-seq dataset. Moreover, cell interaction analysis revealed that subpopulations of B cells in both mouse and human samples are activated and may potentially contribute to oncogenic processes. In summary, our study provides insights into the dynamic immune microenvironment and cellular networks in HCC pathogenesis, with a specific emphasis on naïve B cells. These findings emphasize the significance of targeting TME in HCC patients to prevent HCC pathological progression, which may give a new perspective on the therapeutics for the HCC. Citation Format: Jian He. Leveraging single cell RNA-seq for uncovering immune landscape of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7039.

Abstract 574: Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation

Abstract Nonalcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma (HCC) is an emerging malignancy in the developed countries. However, the mechanisms contributing to its formation remain largely unknown. Given the role of cancer stem cells (CSCs) in tumor initiation and therapeutic resistance, we hypothesize that adipocytes, one of the key cellular factors within the tumor microenvironment of NAFLD-induced HCC, may play a critical role in HCC development and drug resistance by regulating liver CSCs. Using a co-culture system in which differentiated adipocytes were grown with HCC cells, we found that adipocytes enhanced the self-renewal ability of HCC cells through indirect paracrine secretion. HCC cells pre-incubated with conditioned medium from adipocytes showed enhanced liver CSC properties including self-renewal, tumorgenicity, invasiveness and chemo-resistance to doxorubicin and sorafenib. Secretome profiles showed that FABP4 was preferentially secreted by adipocytes and its level was further augmented when co-cultured with HCC cells. Concurrently, recombinant FABP4 enhanced CSC properties of HCC cells. Drastic delay in the onset of tumor development in FABP4−/- mice upon DEN-injected and high fat diet-induced mouse models of NAFLD-HCC. Mass spectrometry analysis revealed ITGB1 as a direct binding partner of FABP4 for the first time. This data, together with the observation of significant downregulation of the Wnt/β-catenin pathway in tumors of FABP4−/− mice, revealed the role of adipocyte-derived FABP4 promotes liver CSC function by activating the PI3K/Akt/β-catenin signaling pathway via ITGB1. Overexpression of ITGB1 led to poorer survival of HCC patients with NAFLD as a risk factor. The development of a monoclonal neutralizing antibody against FABP4 successfully blocked FABP4-driven CSC functions, implicating the targetability of FABP4 for the treatment of NAFLD-induced HCC. Citation Format: Carmen Oi Ning Leung, Shilpa Gurung, Katherine Po Sin Chung, Sze Man Chan, Terence Kin Wah Lee. Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 574.

Abstract 2703: Targeting STING pathway as a therapeutic strategy against β-catenin driven immune escape and resistance to anti-PD1 therapy in hepatocellular carcinoma

Abstract β-catenin mutation occurs in around 40% of hepatocellular carcinoma(HCC); yet no precision therapies are available to treat this tumor subset. Immune checkpoint inhibitors (ICIs) are now widely used for the treatment of patients with advanced HCC. Unfortunately, preliminary evidence showed that β-catenin mutation drives resistance to anti-PD1 immunotherapy in HCC. In this study, we studied the molecular mechanisms underlying β-catenin mutation during HCC pathogenesis to develop novel therapeutics targeting β-Catenin-driven HCC. Firstly, three HCC cohorts were examined, including 70 untreated, 20 treated patients with nivolumab, and patients from a public TCGA database. By single-cell RNA sequencing analysis, we identified that anti-PD-1 treatment displayed effectiveness with the increase of CD27+CD8+ T-cell infiltration, correlating to improved prognosis with longer progression-free survival (PFS) and OS. Importantly, multiplex IHC staining showed that β-catenin activation is associated with significantly reduced CD8+CD27+ T cell infiltration in tumors (n=70), demonstrating that β-catenin promoted immune escape and resistance to anti-PD-1 treatment involved defective cytotoxic T-cell activity. Subsequently, we found that the interaction of β-Catenin with sirtuin 1 (SIRT1) mediated suppression of IRF3/IRF7 activity, resulting in inhibition of Type I interferon (IFN-I) production. However, by CRISPRi screening, we found that disruption of β-catenin-SIRT1 interaction via STING caused persistent high-level IFN-I response which increased the transcription of T-cell costimulatory molecule CD27 via IL10/STAT3/BATF signaling on infiltrated CD8+ T cells. This effect was also confirmed in the STING null mice, emphasizing that STING signaling is a therapeutic target to overcome β-catenin driven immune escape. Further, using hydrodynamic tail-vein injection murine HCC models, we found that the STING agonist inhibited β-catenin-SIRT1 activity, restored IFN signaling to rescue T-cell cytotoxic capacities, and enhanced the anti-PD-1 therapy efficacy. In conclusion, we demonstrated that STING reprogrammed β-Catenin mutated the HCC tumor microenvironment and a combination of STING and anti-PD-1 treatment represents an effective novel therapeutic strategy for HCC patients with β-Catenin mutation. Citation Format: Qingmei Zhang, Jiacheng Bi, Oscar Wai-Ho Yeung, Tao Ding, Wing-Lim Chan, Yueqin Zhu, Jiang Liu, Kevin Tak-Pan Ng, Kwan Man. Targeting STING pathway as a therapeutic strategy against β-catenin driven immune escape and resistance to anti-PD1 therapy in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2703.

RNA processing modification mediated subtypes illustrate the distinctive features of tumor microenvironment in hepatocellular carcinoma.

Multiple transcript isoforms of genes can be formed by processing and modifying the 5' and 3' ends of RNA. Herein, the aim of this study is to uncover the characteristics of RNA processing modification (RPM) in hepatocellular carcinoma (HCC), and to identify novel biomarkers and potential targets for treatment. Firstly, integrated bioinformatics analysis was carried out to identify risk prognostic RPM regulators (RPMRs). Then, we used these RPMRs to identify subtypes of HCC and explore differences in immune microenvironment and cellular function improvement pathways between the sub-types. Finally, we used the principal component analysis algorithms to estimate RPMscore, which were applied to 5 cohorts. Lower RPMscore among patients correlated with a declined survival rate, increased immune infiltration, and raised expression of immune checkpoints, aligning with the "immunity tidal model theory". The RPMscore exhibited robust, which was validated in multiple datasets. Mechanistically, low RPMscore can create an immunosuppressive microenvironment in HCC by manipulating tumor-associated macrophages. Preclinically, patients with high RPMscore might benefit from immunotherapy. The RPMscore is helpful in clustering HCC patients with distinct prognosis and immunotherapy. Our RPMscore model can help clinicians to select personalized therapy for HCC patients, and RPMscore may act a part in the development of HCC.

Immunotherapy and Radiation Therapy Combinatorial Approaches in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC), a prevalent and often fatal liver cancer, presents significant treatment challenges, especially in its advanced stages. This article delves into the promising approach of combining immunotherapy, particularly immune checkpoint inhibitors, with radiation therapy, a cornerstone of HCC management. Our review synthesizes current preclinical and clinical research, highlighting the potential synergistic effects of this combinational treatment. Emerging evidence suggests that this synergy enhances tumor control and improves patient survival rates. The combination leverages the localized, tumor-targeting ability of radiation therapy and the systemic, immune-boosting effects of immunotherapy, potentially overcoming the limitations inherent in each treatment modality when used separately. This integrative approach is especially promising in addressing the complex tumor microenvironment of HCC. However, the treatment landscape is nuanced, with challenges such as patient-specific response variability and potential resistance to therapies. Future research directions should focus on refining these combination strategies, tailoring them to individual patient profiles, and understanding the underlying mechanisms that govern the interaction between immunotherapy and radiation therapy. Such advancements could significantly improve HCC management, setting new standards for patient care and treatment efficacy.

Macrophages as targets in hepatocellular carcinoma therapy.

Hepatocellular carcinoma (HCC) is a malignant tumor with a complex and diverse immunosuppressive microenvironment. Tumor-associated macrophages (TAMs) are an essential component of the tumor immune microenvironment. TAMs typically exist in two primary states: anti-tumor M1 macrophages and pro-tumor M2 macrophages. Remarkably, TAMs possess high plasticity, enabling them to switch between different subtypes or alter their biological functions in response to the tumor microenvironment. Based on research into the biological role of TAMs in the occurrence and development of malignant tumors, including HCC, TAMs are emerging as promising targets for novel tumor treatment strategies. In this review, we provide a detailed introduction to the origin and subtypes of TAMs, elucidate their interactions with other cells in the complex tumor microenvironment of HCC, and describe the biological roles, characteristics, and mechanisms of TAMs in the progression of HCC. Furthermore, we furnish an overview of the latest therapeutic strategies targeting TAMs.