A pan-cancer and single-cell sequencing analysis of CD161, a promising onco-immunological biomarker in tumor microenvironment and immunotherapy

G0S2 Promotes PD-L1 Expression in Monocytes and Influences the Efficacy of PD-1 Inhibitors in Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is a prevalent and highly lethal form of liver cancer, with limited effective treatment options, particularly in the advanced stages. Immunotherapy using PD-1 inhibitors has emerged as a promising treatment modality, yet a substantial proportion of patients exhibit resistance or fail to respond to such therapies. This study aimed to elucidate the role of G0/G1 Switch 2 (G0S2) in regulating PD-L1 expression in monocytes within the HCC tumor microenvironment and to investigate its impact on the efficacy of PD-1 inhibitors. Methods: Gene expression data among HCC patients treated with PD-1 inhibitors were obtained from the HCC single-cell sequencing database; immunohistochemistry was performed to detect G0S2 expression in liver cancer tissues and adjacent non-tumorous tissues of HCC patients; flow cytometry was utilized to analyze the expression of G0S2, PD-L1, CD206, and CD14 in PBMCs from HCC patients; and CD8+T cell proliferation and IFN-γ secretion were used to evaluate the impact of G0S2 knockdown. Results: Utilizing single-cell sequencing data from HCC patients, we identified that G0S2 expression was significantly elevated in the non-responders (NR) compared to responders (R) to PD-1 inhibitor therapy. The immunohistochemical analysis confirmed higher levels of G0S2 in HCC tumor tissues and adjacent non-tumorous tissues, while the flow cytometry revealed the increased expression of G0S2, PD-L1, and CD206 in peripheral blood mononuclear cells (PBMCs) from NR patients compared to R patients and healthy controls. The functional experiments involving the knockdown of G0S2 in the THP-1 monocyte cell line resulted in a significant reduction in PD-L1 expression and a concomitant increase in CD8+T cell proliferation and IFN-γ production. Conclusions: These findings indicate that G0S2 facilitates the upregulation of PD-L1 in monocytes, thereby suppressing T cell activity and contributing to resistance against PD-1 inhibitors in HCC. The high expression of G0S2 in peripheral blood monocytes offers a non-invasive and easily detectable biomarker for predicting the efficacy of PD-1 inhibitor therapy. Consequently, targeting G0S2 may enhance the responsiveness to immunotherapy in HCC patients, providing a new avenue for optimizing treatment strategies and improving patient outcomes.

CD161, a promising prognostic biomarker in hepatocellular carcinoma, correlates with immune infiltration

Background

CD161, encoded by the killer cell lectin-like receptor B1 (KLRB1) gene, exhibits varied roles among different tumors. This study aimed to explore both the potential value of CD161 as a prognostic biomarker for hepatocellular carcinoma (HCC) and its association with immune cell infiltration.

Methods

A total of 109 HCC patients who underwent surgery were retrospectively analyzed. Immunohistochemistry, bioinformatic analyses, and statistical measurements were used to investigate the associations between CD161 expression, immune cell infiltration, and clinical outcomes in both public databases and in-house cohorts.

Results

CD161 was highly expressed at both protein and mRNA levels in adjacent normal tissues compared to tumor tissues of HCC patients. Meanwhile, CD161 was enriched in HCC cases characterized by smaller tumor sizes (≤5 cm) and the absence of portal vein tumor thrombus. Individuals with high CD161 expression showed extended overall survival (OS) and relapse free survival (RFS) compared to those with lower CD161 levels. CD161 was identified as an independent prognostic indicator for both OS and RFS. In addition, the enrichment analysis indicated a close correlation between CD161 and immune response, as well as between CD161 and the signaling pathways of cytokines and chemokines, implying its role in immune regulation during cancer development. Specifically, CD161 expression was positively associated with immunomodulators and tumor-infiltrating immune cells, especially CD8+T cells, CD4+T cells, and dendritic cells. Multiple public databases showed that patients with high CD161 expression were more likely to derive benefits from immunotherapy.

Conclusion

CD161 was identified as a promising prognostic biomarker for HCC, as its expression indicates a favorable prognosis. Additionally, CD161 is closely linked to high infiltration of immune cells, participates in the regulation of the tumor immune microenvironment, and holds promise as a potential biomarker for predicting the efficacy of immunotherapy.

Wnt signaling in the tumor microenvironment: A driver of brain tumor dynamics

The Wnt signaling pathway is important for cell growth and development in the central nervous system and its associated vasculature. Thus, it is an interesting factor for establishing anti-brain cancer therapy. However, simply inhibiting the Wnt signaling pathway in patients with brain tumors is not an effective anti-cancer therapy. Due to their complex microenvironment, which comprises various cell types and signaling molecules, brain tumors pose significant challenges. It is important to understand the interplay between tumor cells and the microenvironment for developing effective therapeutic strategies for both benign and malignant brain tumors. Thus, this research focused on the role of the tumor microenvironment (TME) in brain tumor progression, particularly the involvement of Wnt-dependent signaling pathways. The brain parenchyma comprises neurons, glia, endothelial cells, and other extracellular matrix elements that can contribute to the TME. The TME components can secrete Wnt ligands or associated molecules, resulting in the aberrant activation of the Wnt signaling pathway, followed by tumor progression and therapeutic resistance. Therefore, it is essential to understand the intricate crosstalk between the Wnt signaling pathway and the TME in developing targeted therapies. This review aimed to elucidate the complexities of the brain TME and its interactions with the Wnt signaling pathways to improve treatment outcomes and our understanding of brain tumor biology.

Comprehensive pan-cancer analysis of KLRB1-CLEC2D pair and identification of small molecule inhibitors to disrupt their interaction

The interplay between immune checkpoints KLRB1 and CLEC2D is crucial for tumor progression and immune evasion, yet the interaction dynamics are not fully understood. This study aims to elucidate the interaction across various cancers and identify small molecule inhibitors that can disrupt it. We perform a comprehensive pan-cancer analysis of the KLRB1-CLEC2D pair, including mRNA expression patterns, pathological stages, survival outcomes, and single-cell omics, immune infiltration, copy number variations, and DNA methylation profiles. Our findings reveal a consistently higher CLEC2D/KLRB1 ratio in most cancer types compared to normal tissues, and this ratio also increased with advancing pathological stages. Lower KLRB1 expression correlated with higher mortality in most cancers, opposite to CLEC2D. Expression variations were attributed to differential lymphocyte infiltration, CNV, and DNA methylation. Structure-based virtual screening analysis identified compounds including forsythiaside A and RGD peptides as effective inhibitors of the KLRB1-CLEC2D interaction, validated through microscale thermophoresis. This research advances understanding of the KLRB1-CLEC2D interaction within the tumor microenvironment and introduces novel therapeutic strategies to modulate this interaction.

Necroptosis-related KLRB1 was a potent tumor suppressor and immunotherapy determinant in breast cancer

Breast cancer is a multifaceted and diverse illness that impacts millions of people globally. Identifying the underlying causes of BRCA and creating efficient treatment plans are urgent. Necroptosis is widely involved in cancer development. However, the specific roles of necroptosis in cancer immunotherapy of breast cancer have not been explored. In this study, we aim to establish the connection between necroptosis and immunotherapy in BRCA. TCGA, METABRIC, GSE103091, GSE159956, and GSE96058 were included for bioinformatics analysis. NMF and CoxBoost algorithms were used to develop the necroptosis-related patterns and model, respectively. A necroptosis-related model was developed and determined KLRB1 as a critical tumor suppressor by in vitro validation. The mutation characteristics, immune characteristics, and molecular functions of KLRB1 were explored. We further examined how necroptosis-related KLRB1 functions in BRCA as a powerful tumor suppressor and regulates the activity of macrophages by in vitro validation, including CCK8, EdU, and Transwell assays. KLRB1 was also revealed to be an immunotherapy determinant.

Unlocking the potential of T-cell metabolism reprogramming: Advancing single-cell approaches for precision immunotherapy in tumour immunity

As single-cell RNA sequencing enables the detailed clustering of T-cell subpopulations and facilitates the analysis of T-cell metabolic states and metabolite dynamics, it has gained prominence as the preferred tool for understanding heterogeneous cellular metabolism. Furthermore, the synergistic or inhibitory effects of various metabolic pathways within T cells in the tumour microenvironment are coordinated, and increased activity of specific metabolic pathways generally corresponds to increased functional activity, leading to diverse T-cell behaviours related to the effects of tumour immune cells, which shows the potential of tumour-specific T cells to induce persistent immune responses. A holistic understanding of how metabolic heterogeneity governs the immune function of specific T-cell subsets is key to obtaining field-level insights into immunometabolism. Therefore, exploring the mechanisms underlying the interplay between T-cell metabolism and immune functions will pave the way for precise immunotherapy approaches in the future, which will empower us to explore new methods for combating tumours with enhanced efficacy.

Immune checkpoint CD161/LLT1-associated immunological landscape and diagnostic value in oral squamous cell carcinoma

An active host adaptive response is characterized by the existence of programmed cell death protein 1 (PD-1)+ /IFN-γ+ cytotoxic T cells and IFN-γ-induced PD-L1+ tumor cells (TCs), which predicts high response rate to anti-PD-1/L1 therapy. Recently, CD161 and its ligand LLT1 (CLEC2D) have been identified as an emerging checkpoint for immunotherapy. Clarifying its heterogeneous clinical expression pattern and its immune landscape is a prerequisite for maximizing the response rate of CD161 blockade therapy in a specific population of oral squamous cell carcinoma (OSCC) patients. Here, we investigated the expression pattern of CD161/LLT1 and its association with major immunocytes (T cells, B cells, NK cells, and macrophages) by multiplex immunofluorescence, immunohistochemistry, and flow cytometry in 109 OSCC tissues and 102 peripheral blood samples. TCs showed higher LLT1 levels than tumor infiltrating lymphocytes (TILs), whereas CD161 was highly expressed in CD8+ T cells at the tumor front, which was decreased in paracancerous tissue. High expression of TC-derived LLT1 (LLT1TC ) conferred poor clinical outcomes, whereas higher CD161+ and LLT1+ TILs were associated with better prognosis. Meanwhile, patients with high LLT1TC showed a decreased ratio of CD8+ /Foxp3+ T cells in situ, but CD161+ TILs correlated with more peripheral CD3+ T cells. Interestingly, treatment of OSCC patients with nivolumab (anti-PD-1) could restore tumoral CD161/LLT1 signal. Furthermore, an OSCC subgroup characterized by high LLT1+ TCs and low CD161+ CD8+ T cells showed fewer peripheral T cells and a higher risk of lymph node metastasis, leading to a shorter 5-year survival time (29%). More LLT1TC at the invasive front was another risk characteristic of exhausted T cells. In conclusion, in view of this heterogeneity, the LLT1/CD161 distribution pattern should be determined before CD161-based immunotherapy.