Juanjuan Shan

Human leukocyte antigen (HLA) molecules play a pivotal role in antigen presentation. Tumor cells present neoantigens on the cell surface via HLA molecules,

Cancers often originate from precursor cells within an inflamed microenvironment; however, the mechanisms by which these precursors manipulate the niche to promote tumorigenesis remain unclear. By combining single-cell and spatial transcriptomic analyses of precancerous lesions in hepatocellular carcinoma, here we show that elevated myocyte enhancer factor 2D (MEF2D)-expressing cancer precursors reprogram liver-resident macrophages, Kupffer cells (KCs), to create a growth-supportive environment. MEF2D levels induce an oncogenic and secretory phenotype in these precursors by epigenetic reprogramming, which is crucial for tumor initiation in murine models and human samples. This results in a KC-rich niche through paracrine activation of neuropilin 1 (NRP1) signaling on stem-like KC subtype-2 (KC2), driving its differentiation into KC subtype-1 (KC1)-like cells. Pro-inflammatory KC1s release cytokines, particularly IL-6, to enhance an MEF2D-mediated tumor-promoting program in nearby cancer precursors. Targeting NRP1 signaling disrupts the KC2-to-KC1-like differentiation and reduces niche inflammation, thereby inhibiting liver tumorigenesis in male mice. Thus, preventing aberrant KC subtype conversion in the precancerous microenvironment is a viable strategy for early cancer prevention.

Two decades after the initial report on increased micronuclei in human chronic liver disease (CLD) and hepatocellular carcinoma (HCC), their role in HCC development is still poorly understood. Here, we show that micronuclei in hepatocytes trigger a hepatic immune response and promote HCC development via an increased level of extrachromosomal circular DNA (eccDNA). Livers of a CLD model ( Mcl1 ^Δhep mice) show increased micronuclei and eccDNA levels. Circular sequencing confirms higher eccDNA levels in micronuclei compared to primary nuclei. The nuclei-segregated DNA fiber (NuSeF) assay we developed demonstrates that micronuclei are more susceptible to replication stress, exhibiting increased replication fork slowing. Comparing different murine liver disease models reveals that high eccDNA correlates with an increased tumor incidence. eccDNA is a strong immunostimulant and promotes a cross-talk between hepatocytes and immune cells through the cGAS-STING pathway. Deletion of Sting1 in Mcl1 ^Δhep mice reduces immune cell chemotaxis and tumor incidence. Our findings suggest that eccDNA from micronuclei mediates inflammation-driven liver carcinogenesis in CLD.

Despite advances in cancer therapies, treatment responses remain highly variable due to the complexity and heterogeneity of the tumor microenvironment. The tumor microenvironment comprises malignant, immune, stromal, and endothelial cells, along with extracellular matrix and soluble factors, all organized into spatially distinct communities that evolve dynamically throughout tumor progression and therapy. These spatial structures orchestrate tumor behavior, immune evasion, and drug resistance. Recent breakthroughs in spatial omics technologies, including spatial transcriptomics and spatial proteomics, have enabled high-resolution, multiplexed mapping of tissue architecture and molecular characteristics. These technologies provide valuable insights into how the spatial organization of cells and signaling networks within the tumor microenvironment influences therapeutic efficacy. Notably, specific structures, such as tertiary lymphoid structures, fibroblast-mediated stromal barriers, and vascular heterogeneity have been identified as spatial determinants of treatment response. By delineating cellular communities and their interactions, spatial omics technologies can reduce intratumoral complexity into clinically interpretable modules. This review summarizes the diversity of these spatial structures and their relationships with treatment outcomes in immunotherapy, chemotherapy, radiotherapy, and targeted therapy. In addition, it highlights present challenges in data integration, analytical standardization, and functional validation, and discusses future directions for incorporating spatial omics technologies into precision medicine.

Immunotherapy exhibited potential effects for advanced hepatocellular carcinoma, unfortunately, the clinical benefits are often countered by cancer adaptive immune suppressive response. Uncovering the mechanism how cancer cells evade immune surveillance would help to develop new immunotherapy approaches and combination therapy. In this article, by analyzing the transcriptional factors which modulate the differentially expressed genes between T cell infiltration high group and low group, we identified oncoprotein B cell lymphoma 6 (BCL6) suppresses the infiltration and activation of tumor infiltrating T lymphocytes, thus correlated with poorer clinical outcome. By using antibody deletion experiment, we further demonstrated that CD4⁺T cells but not CD8⁺T cells are the main lymphocyte population suppressed by Bcl6 to promote HCC development. Mechanistically, BCL6 decreases cancer cell expression of pro-inflammatory cytokines and T lymphocyte chemokines such as IL6, IL1F6, and CCL5. Moreover, BCL6 upregulates Endothelial cell-specific molecule 1 (ESM1) to inhibit T lymphocyte recruitment and activation possibly through ICAM-1/LFA-1 signaling pathway. Our findings uncovered an unappreciated paracrine mechanism how cancer cell-derived BCL6 assists cancer cell immune evasion, and highlighted the role of CD4⁺T cells in HCC immune surveillance.

Hepatocellular carcinoma (HCC) has become the fourth leading cause of cancer-related deaths worldwide; annually, approximately 830,000 deaths related to liver cancer are diagnosed globally. Since early-stage HCC is clinically asymptomatic, traditional treatment modalities, including surgical ablation, are usually not applicable or result in recurrence. Immunotherapy, particularly immune checkpoint blockade (ICB), provides new hope for cancer therapy; however, immune evasion mechanisms counteract its efficiency. In addition to viral exposure and alcohol addiction, nonalcoholic steatohepatitis (NASH) has become a major cause of HCC. Owing to NASH-related aberrant T cell activation causing tissue damage that leads to impaired immune surveillance, NASH-associated HCC patients respond much less efficiently to ICB treatment than do patients with other etiologies. In addition, abnormal inflammation contributes to NASH progression and NASH–HCC transition, as well as to HCC immune evasion. Therefore, uncovering the detailed mechanism governing how NASH-associated immune cells contribute to NASH progression would benefit HCC prevention and improve HCC immunotherapy efficiency. In the following review, we focused our attention on summarizing the current knowledge of the role of CD4⁺T cells in NASH and HCC progression, and discuss potential therapeutic strategies involving the targeting of CD4⁺T cells for the treatment of NASH and HCC.

The widespread use of immune checkpoint inhibitors (ICIs) has demonstrated significant survival benefits for cancer patients and also carry the risk of immune-related adverse events (irAEs). ICIs-associated myocarditis is a rare and serious adverse event with a high mortality rate. Here, we explored the mechanism underlying ICIs-associated myocarditis. Using the peripheral blood of patients with ICIs therapy and ICIs treated mice with transplanted tumors, we dissect the immune cell subsets and inflammatory factors associated with myocarditis. Compared to the control group, patients with myocarditis after ICIs therapy showed an increase in NK cells and myeloid cells in peripheral blood, while T cells significantly decreased. Among T cells, there was an imbalance of CD4/CD8 ratio in the peripheral blood of myocarditis patients, with a significant decrease in central memory CD4+ T (CD4+ T_CM) cells. RNA-Seq revealed that CD4+ T_CM cells in myocarditis patients were an immunosuppressive cell subset, which highly express the immunosuppressive factor IL4I1. To elucidate the potential mechanism of the decrease in CD4+ T_CM cells, protein array was performed and revealed that several inflammatory factors gradually increased with the severity of myocarditis in the myocarditis group, such as IL-1B/CXCL13/CXCL9, while the myocardial protective factor IL-15 decreased. Correlation analysis indicated a positive correlation between IL-15 and CD4+ T_CM cells, with high expression of IL-15 receptor IL15RA. Furthermore, in vivo studies using an anti-PDL1 antibody in a mouse tumor model indicated a reduction in CD4+ T_CM cells and an increase in CD8+ T_EMRA cells, alongside evidence of cardiac fibrosis. Conversely, combining anti-PDL1 antibody treatment with IL-15 led to a resurgence of CD4+ T_CM cells, a reduction in CD8+ T_EMRA cells, and a mitigated risk of cardiac fibrosis. Our data highlight CD4+ T_CM cells as a crucial role in cardiac protection during ICIs therapy. IL-15, IL4I1 and CD4+ T_CM cells can serve as therapeutic targets to reduce ICIs-associated myocarditis in cancer patients.

12 supplementary figures and 2 supplementary tables

Expanding the utility of chimeric antigen receptor (CAR)-T cells in solid tumors requires improving their efficacy and safety. Hypoxia is a feature of most solid tumors that could be used to help CAR-T cells discriminate tumors from normal tissues. In this study, we developed hypoxia-responsive CAR-T cells by engineering the CAR to be under regulation of hypoxia-responsive elements and selected the optimal structure (5H1P-CEA CAR), which can be activated in the tumor hypoxic microenvironment to induce CAR-T cells with high polyfunctionality. Hypoxia-responsive CAR T cells were in a “resting” state with low CAR expression under normoxic conditions. Compared with conventional CAR-T cells, hypoxia-responsive CAR-T cells maintained lower differentiation and displayed enhanced oxidative metabolism and proliferation during cultivation, and they sowed a capacity to alleviate the negative effects of hypoxia on T-cell proliferation and metabolism. Furthermore, 5H1P-CEA CAR-T cells exhibited decreased T-cell exhaustion and improved T-cell phenotype in vivo. In patient-derived xenograft models, hypoxia-responsive CAR-T cells induced more durable antitumor activity than their conventional counterparts. Overall, this study provides an approach to limit CAR expression to the hypoxic tumor microenvironment that could help to enhance CAR T-cell efficacy and safety in solid tumors.Significance:Engineering CAR-T cells to upregulate CAR expression under hypoxic conditions induces metabolic reprogramming, reduces differentiation, and increases proliferation to enhance their antitumor activity, providing a strategy to improve efficacy and safety.