Intratumoral PPT1-positive macrophages determine immunosuppressive contexture and immunotherapy response in hepatocellular carcinoma

Single-cell multi-omics in the study of digestive system cancers

Digestive system cancers are prevalent diseases with a high mortality rate, posing a significant threat to public health and economic burden. The diagnosis and treatment of digestive system cancer confront conventional cancer problems, such as tumor heterogeneity and drug resistance. Single-cell sequencing (SCS) emerged at times required and has developed from single-cell RNA-seq (scRNA-seq) to the single-cell multi-omics era represented by single-cell spatial transcriptomics (ST). This article comprehensively reviews the advances of single-cell omics technology in the study of digestive system tumors. While analyzing and summarizing the research cases, vital details on the sequencing platform, sample information, sampling method, and key findings are provided. Meanwhile, we summarize the commonly used SCS platforms and their features, as well as the advantages of multi-omics technologies in combination. Finally, the development trends and prospects of the application of single-cell multi-omics technology in digestive system cancer research are prospected.

Qizhu anticancer prescription enhances immunosurveillance of liver cancer cells by regulating p21-dependent secretory phenotypes

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide, largely due to the limitations of available therapeutic strategies. The traditional Chinese medicine Qizhu Anticancer Prescription (QZACP) can improve the quality of life and prolong the survival time of patients with HCC. However, the precise mechanisms underlying the anti-cancer properties of QZACP remain unclear.

PURPOSE

This study examined the anti-hepatocarcinogenic properties of QZACP, with a specific focus on its influence on the p21-activated secretory phenotype (PASP)-mediated immune surveillance, to elucidate the underlying molecular pathways involved in HCC.

MATERIALS AND METHODS

Cell proliferation was measured using the Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, and clonogenic assays. The cell cycle was evaluated using flow cytometry, and senescence was identified by staining with senescence-associated beta-galactosidase (SA-β-gal). A primary liver cancer model produced by diethylnitrosamine was established in C57 BL/6 mice to assess the tumor-inhibitory effect of QZACP. The liver's pathological characteristics were examined using hematoxylin and eosin staining. PASP screening was performed using GeneCards, DisGeNet, Online Mendelian Inheritance in Man, and The Cancer Genome Atlas databases. Western blot analysis, enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining, and Transwell migration assays were performed.

RESULTS

Serum containing QZACP enhanced p21 expression, triggered cell cycle arrest, accelerated cell senescence, and suppressed cell proliferation in Huh7 and MHCC-97H liver cancer cells. QZACP reduced the quantity and dimensions of liver tumor nodules and enhanced p21 protein expression, SA-β-Gal staining in tumor lesions, and cytotoxic CD8+ T cell infiltration. Bioinformatic analyses indicated that PASP factors, including hepatocyte growth factor, decorin (DCN), dermatopontin, C-X-C motif chemokine ligand 14 (CXCL14), and Wnt family member 2 (WNT2), play an important role in the development of HCC. In addition, these factors are associated with the presence of natural killer cells and CD8+ T cells within tumors. Western blotting and ELISA confirmed that QZACP increased DCN, CXCL14, and WNT2 levels in tumor tissues and peripheral blood.

CONCLUSIONS

QZACP's suppression of HCC progression may involve cell senescence mediated via p21 upregulation, DCN, CXCL14, and WNT2 secretion, and reversal of the immunosuppressive microenvironment. This study provides insights that can be used in the development of new treatment strategies for HCC.

ANXA3-Rich Exosomes Derived from Tumor-Associated Macrophages Regulate Ferroptosis and Lymphatic Metastasis of Laryngeal Squamous Cell Carcinoma

Tumor-associated macrophages (TAM) induce immunosuppression in laryngeal squamous cell carcinoma (LSCC). The interaction between LSCC cells and TAMs affects the progression of laryngeal cancer through exosomes, but the underlying molecular mechanism remains unclear. Proteomics analysis of TAMs isolated from human laryngeal tumor tissues obtained from patients with confirmed lymphatic metastasis revealed an upregulation of annexin A3 (ANXA3). In TAMs, ANXA3 promoted macrophages to polarize to an M2-like phenotype by activating the AKT-GSK3β-β-catenin pathway. In addition, ANXA3-rich exosomes derived from TAMs inhibited ferroptosis in laryngeal cancer cells through an ATF2-CHAC1 axis, and this process was associated with lymphatic metastasis. Mechanistically, ANXA3 in exosomes inhibited the ubiquitination of ATF2, whereas ATF2 acted as a transcription factor to regulate the expression of CHAC1, thus inhibiting ferroptosis in LSCC cells. These data indicate that abnormal ANXA3 expression can drive TAM reprogramming and promote an immunosuppressive microenvironment in LSCC. Meanwhile, ANXA3-rich exosomes inhibit ferroptosis of LSCC cells and promote lymphatic metastasis, thus promoting tumor progression.

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.

Characterizing ligand-receptor interactions and unveiling the pro-tumorigenic role of CCL16-CCR1 axis in the microenvironment of hepatocellular carcinoma

Background

The heterogeneity of the tumor microenvironment significantly influences the prognosis of hepatocellular carcinoma (HCC) patients, with cell communication through ligand-receptor complexes playing a central role.

Methods

We conducted single-cell transcriptomic analysis on ten HCC tissues to identify ligand-receptor genes involved in malignant HCC cell communication using CellChat. Leveraging RNA-Seq data from the TCGA Liver Cancer (TCGA-LIHC) and Liver Cancer - RIKEN, JP (LIRI-JP) cohorts, we employed Cox regression analysis to screen for prognosis-related genes. Prognostic risk models were constructed through unsupervised clustering and differential gene expression analysis. Subsequently, a co-culture system involving tumor cells and macrophages was established. A series of experiments, including Transwell assays, immunofluorescence staining, immunoprecipitation, flow cytometry, and immunohistochemistry, were conducted to elucidate the mechanism through which HCC cells recruit macrophages via the CCL16-CCR1 axis.

Results

Single-cell analysis unveiled significant interactions between malignant HCC cells and macrophages, identifying 76 related ligand-receptor genes. Patients were classified into three subtypes based on the expression patterns of eight prognosis-related ligand-receptor genes. The subtype with the worst prognosis exhibited reduced infiltration of T cell-related immune cells, downregulation of immune checkpoint genes, and increased M2-like tumor-associated macrophage scores. In vitro experiments confirmed the pivotal role of the CCL16-CCR1 axis in the recruitment and M2 polarization of tumor-associated macrophages. Clinical samples demonstrated a significant association between CCL16 protein expression levels and advanced stage, lymph node metastasis, and distant metastasis. Immunohistochemistry and immunofluorescence staining further confirmed the correlation between CCL16 and CCR1, CD68, and CD206, as well as CD68+CCR1+ macrophage infiltration.

Conclusions

Our study identified molecular subtypes, a prognostic model, and immune microenvironment features based on ligand-receptor interactions in malignant HCC cell communication. Moreover, we revealed the pro-tumorigenic role of HCC cells in recruiting M2-like tumor-associated macrophages through the CCL16-CCR1 axis.

The core role of macrophages in hepatocellular carcinoma: the definition of molecular subtypes and the prognostic risk system

Background: In patients with hepatocellular carcinoma (HCC), the tumor microenvironment (TME) is resistant to immunotherapy because of its specificity. It is meaningful to explore the role of macrophage, which is one of the most abundant immune cells in the TME, in cellular communication and its effect on the prognosis and immunotherapy of HCC. Methods: Dimensionality reduction and clustering of the single-cell RNA-seq data from the GSE149614 dataset were carried out to identify the cellular composition of HCC. CellChat was used to analyze the communication between different cells. The specifically highly expressed genes of macrophages were extracted for univariate Cox regression analysis to obtain prognostic genes for HCC cluster analysis, and the risk system of macrophage-specifically highly expressed genes was developed by random forest analysis and multivariate Cox regression analysis. Prognosis, TME infiltration, potential responses to immunotherapy, and antineoplastic drugs were compared among molecular subtypes and between risk groups. Results: We found that HCC included nine identifiable cell types, of which macrophages had the highest communication intensity with each of the other eight cell types. Of the 179 specifically highly expressed genes of macrophage, 56 were significantly correlated with the prognosis of HCC, which classified HCC into three subtypes, which were reproducible and produced different survival outcomes, TME infiltration, and immunotherapy responses among the subtypes. In the integration of four macrophage-specifically highly expressed genes for the development of a risk system, the risk score was significantly involved in higher immune cell infiltration, poor prognosis, immunotherapy response rate, and sensitivity of six drugs. Conclusion: In this study, through single-cell RNA-seq data, we identified nine cell types, among which macrophage had the highest communication intensity with the rest of the cell types. Based on specifically highly expressed genes of macrophage, we successfully divided HCC patients into three clusters with distinct prognosis, TME, and therapeutic response. Additionally, a risk system was constructed, which provided a potential reference index for the prognostic target and preclinical individualized treatment of HCC.