The pros and cons of dying tumour cells in adaptive immune responses

Comprehensive scRNA-seq Analysis and Identification of CD8_+T Cell Related Gene Markers for Predicting Prognosis and Drug Resistance of Hepatocellular Carcinoma

BACKGROUND

Tumor heterogeneity of immune infiltration of cells plays a decisive role in hepatocellular carcinoma (HCC) therapy response and prognosis. This study investigated the effect of different subtypes of CD8+T cells on the HCC tumor microenvironment about its prognosis.

METHODS

Single-cell RNA sequencing, transcriptome, and single-nucleotide variant data from LUAD patients were obtained based on the GEO, TCGA, and HCCD18 databases. CD8+ T cells-associated subtypes were identified by consensus clustering analysis, and genes with the highest correlation with prognostic CD8+ T cell subtypes were identified using WGCNA. The ssGSEA and ESTIMATE algorithms were used to calculate pathway enrichment scores and immune cell infiltration levels between different subtypes. Finally, the TIDE algorithm, CYT score, and tumor responsiveness score were utilized to predict patient response to immunotherapy.

RESULTS

We defined 3 CD8+T cell clusters (CD8_0, CD8_1, CD8_2) based on the scRNA- seq dataset (GSE149614). Among, CD8_2 was prognosis-related risk factor with HCC. We screened 30 prognosis genes from CD8_2, and identified 3 molecular subtypes (clust1, clust2, clust3). Clust1 had better survival outcomes, higher gene mutation, and enhanced immune infiltration. Furthermore, we identified a 12 genes signature (including CYP7A1, SPP1, MSC, CXCL8, CXCL1, GCNT3, TMEM45A, SPP2, ME1, TSPAN13, S100A9, and NQO1) with excellent prediction performance for HCC prognosis. In addition, High-score patients with higher immune infiltration benefited less from immunotherapy. The sensitivity of low-score patients to multiple drugs including Parthenolide and Shikonin was significantly higher than that of high-score patients. Moreover, high-score patients had increased oxidative stress pathways scores, and the RiskScore was closely associated with oxidative stress pathways scores. And the nomogram had good clinical utility.

CONCLUSION

To predict the survival outcome and immunotherapy response for HCC, we developed a 12-gene signature based on the heterogeneity of the CD8+ T cells.

Identification of a Novel CD8+ T cell exhaustion-related gene signature for predicting survival in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a major health concern, necessitating a deeper understanding of its prognosis and underlying mechanisms. This study aimed to investigate the mechanism and prognostic value of CD8+ T Cell exhaustion (CD8+ TEX)-related genes in HCC and construct a survival prognosis prediction model for patients with HCC.

METHODS

CD8+ TEX-related genes associated with HCC prognosis were analysed and identified, and a prognostic prediction model was constructed using the 'least absolute shrinkage and selection operator' Cox regression model. Immunohistochemistry was used to verify the expression of the model genes in HCC tissues. A nomogram was constructed based on risk scores and clinical features, and its predictive efficacy was verified. The expression of STAM, ANXA5, and MAD2L2 in HCC cell lines was detected by western blotting; subsequently, these genes were knocked down in HCC cell lines by small interfering RNA, and their effects on the proliferation and migration of HCC cell lines were detected by colony formation assay, cck8, wound healing, and transwell assays.

RESULTS

Six genes related to CD8+ TEX were included in the risk-prediction model. The prognosis of patients with HCC in the low-risk group was significantly better than that of those in the high-risk group. Cox regression analysis revealed that the risk score was an independent risk factor for the prognosis of patients with HCC. The differentially expressed genes in patients with high-risk HCC were mainly enriched in the nucleotide-binding oligomerization domain-containing protein-like receptor, hypoxia-inducible factor-1, and tumour programmed cell death protein (PD)-1/PD-L1 immune checkpoint pathways. The CD8+ TEX-related genes STAM, ANXA5, and MAD2L2 were knocked down in HCC cell lines to significantly inhibit cell proliferation and migration. The prediction results of the nomogram based on the risk score showed a good fit and application value.

CONCLUSION

The prediction model based on CD8+ TEX-related genes can predict the prognosis of HCC and provide a theoretical basis for the early identification of patients with poor HCC prognosis.

New insights into T-cell exhaustion in liver cancer: from mechanism to therapy

Liver cancer is one of the most common malignancies. T-cell exhaustion is associated with immunosuppression of tumor and chronic infection. Although immunotherapies that enhance the immune response by targeting programmed cell death-1(PD-1)/programmed cell death ligand 1 (PD-L1) have been applied to malignancies, these treatments have shown limited response rates. This suggested that additional inhibitory receptors (IRs) also contributed to T-cell exhaustion and tumor prognosis. Exhausted T-cells (Tex) in the tumor immune microenvironment (TME) are usually in a dysfunctional state of exhaustion, such as impaired activity and proliferative ability, increased apoptosis rate, and reduced production of effector cytokines. Tex cells participate in the negative regulation of tumor immunity mainly through IRs on the cell surface, changes in cytokines and immunomodulatory cell types, causing tumor immune escape. However, T-cell exhaustion is not irreversible and targeted immune checkpoint inhibitors (ICIs) can effectively reverse the exhaustion of T-cells and restore the anti-tumor immune response. Therefore, the research on the mechanism of T-cell exhaustion in liver cancer, aimed at maintaining or restoring the effector function of Tex cells, might provide a new method for the treatment of liver cancer. In this review, we summarized the basic characteristics of Tex cells (such as IRs and cytokines), discussed the mechanisms associated with T-cell exhaustion, and specifically discussed how these exhaustion characteristics were acquired and shaped by key factors within TME. Then new insights into the molecular mechanism of T-cell exhaustion suggested a potential way to improve the efficacy of cancer immunotherapy, namely to restore the effector function of Tex cells. In addition, we also reviewed the research progress of T-cell exhaustion in recent years and provided suggestions for further research.

Spontaneous cancer remission after COVID-19: insights from the pandemic and their relevance for cancer treatment

Early in the COVID-19 pandemic, it emerged that the risk of severe outcomes was greater in patients with co-morbidities, including cancer. The huge effort undertaken to fight the pandemic, affects the management of cancer care, influencing their outcome. Despite the high fatality rate of COVID-19 disease in cancer patients, rare cases of temporary or prolonged clinical remission from cancers after SARS-CoV-2 infection have been reported. We have reviewed sixteen case reports of COVID-19 disease with spontaneous cancer reduction of progression. Fourteen cases of remission following viral infections and two after anti-SARS-CoV-2 vaccination. The immune response to COVID-19, may be implicated in both tumor regression, and progression. Specifically, we discuss potential mechanisms which include oncolytic and priming hypotheses, that may have contributed to the cancer regression in these cases and could be useful for future options in cancer treatment.

Elevated STIL predicts poor prognosis in patients with hepatocellular carcinoma

Overexpression of SCL/TAL1 interrupting locus (STIL) has been observed in various cancer types. However, the clinical significance of STIL in hepatocellular carcinoma (HCC) remains unknown. Cox regression and Kaplan-Meier survival analyses were performed to evaluate the prognostic value of STIL. Go and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were also carried out. Immune infiltrates analyses were conducted based on TIMER (Tumor Immune Estimation Resource) and GAPIA databases. STIL expression was highly expressed in HCC tissues, based on multiple databases. KEGG and GO enrichment analysis showed STIL-related to tumorigenesis and progress. Furthermore, STIL was significantly correlated with immune infiltration. STIL serves as a biomarker for the prediction of patient survival.

Classical epithelial-mesenchymal transition (EMT) and alternative cell death process-driven blebbishield metastatic-witch (BMW) pathways to cancer metastasis

Metastasis is a pivotal event that accelerates the prognosis of cancer patients towards mortality. Therapies that aim to induce cell death in metastatic cells require a more detailed understanding of the metastasis for better mitigation. Towards this goal, we discuss the details of two distinct but overlapping pathways of metastasis: a classical reversible epithelial-to-mesenchymal transition (hybrid-EMT)-driven transport pathway and an alternative cell death process-driven blebbishield metastatic-witch (BMW) transport pathway involving reversible cell death process. The knowledge about the EMT and BMW pathways is important for the therapy of metastatic cancers as these pathways confer drug resistance coupled to immune evasion/suppression. We initially discuss the EMT pathway and compare it with the BMW pathway in the contexts of coordinated oncogenic, metabolic, immunologic, and cell biological events that drive metastasis. In particular, we discuss how the cell death environment involving apoptosis, ferroptosis, necroptosis, and NETosis in BMW or EMT pathways recruits immune cells, fuses with it, migrates, permeabilizes vasculature, and settles at distant sites to establish metastasis. Finally, we discuss the therapeutic targets that are common to both EMT and BMW pathways.

Glutamine deprivation impairs function of infiltrating CD8+ T cells in hepatocellular carcinoma by inducing mitochondrial damage and apoptosis

BACKGROUND

The functions of infiltrating CD8⁺ T cells are often impaired due to tumor cells causing nutrient deprivation in the tumor microenvironment. Thus, the mechanisms of CD8⁺ T cell dysfunction have become a hot research topic, and there is increased interest on how changes in metabolomics correlate with CD8⁺ T cell dysfunction.

AIM

To investigate whether and how glutamine metabolism affects the function of infiltrating CD8⁺ T cells in hepatocellular carcinoma.

METHODS

Immunohistochemical staining and immunofluorescence were performed on surgically resected liver tissues from patients. Differentially expressed genes in infiltrating CD8⁺ T cells in hepatocellular carcinoma were detected using RNA sequencing. Activated CD8⁺ T cells were co-cultured with Huh-7 cells for 3 d. The function and mitochondrial status of CD8⁺ T cells were analyzed by flow cytometry, quantitative real-time polymerase chain reaction, and transmission electron microscopy. Next, CD8⁺ T cells were treated with the mitochondrial protective and damaging agents. Functional alterations in CD8⁺ T cells were detected by flow cytometry. Then, complete medium without glutamine was used to culture cells and their functional changes and mitochondrial status were detected.

RESULTS

There were a large number of infiltrating PD-1⁺CD8⁺ T cells in liver cancer tissues. Next, we co-cultured CD8⁺ T cells and Huh-7 cells to explore the regulatory effect of hepatoma cells on CD8⁺ T cells. Flow cytometry results revealed increased PD-1 expression and decreased secretion of perforin (PRF1) and granzyme B (GZMB) by CD8⁺ T cells in the co-culture group. Meanwhile, JC-1 staining was decreased and the levels of reactive oxygen species and apoptosis were increased in CD8⁺ T cells of the co-culture group; additionally, the mitochondria of these cells were swollen. When CD8⁺ T cells were treated with the mitochondrial protective and damaging agents, their function was restored and inhibited, respectively, through the mitochondrial damage and apoptotic pathways. Subsequently, complete medium without glutamine was used to culture cells. As expected, CD8⁺ T cells showed functional downregulation, mitochondrial damage, and apoptosis.

CONCLUSION

Glutamine deprivation impairs the function of infiltrating CD8⁺ T cells in hepatocellular carcinoma through the mitochondrial damage and apoptotic pathways.

Cancer Occurrence as the Upcoming Complications of COVID-19

Previous studies suggested that patients with comorbidities including cancer had a higher risk of mortality or developing more severe forms of COVID-19. The interaction of cancer and COVID-19 is unrecognized and potential long-term effects of COVID-19 on cancer outcome remain to be explored. Furthermore, whether COVID-19 increases the risk of cancer in those without previous history of malignancies, has not yet been studied. Cancer progression, recurrence and metastasis depend on the complex interaction between the tumor and the host inflammatory response. Extreme proinflammatory cytokine release (cytokine storm) and multi-organ failure are hallmarks of severe COVID-19. Besides impaired T-Cell response, elevated levels of cytokines, growth factors and also chemokines in the plasma of patients in the acute phase of COVID-19 as well as tissue damage and chronic low-grade inflammation in "long COVID-19" syndrome may facilitate cancer progression and recurrence. Following a systemic inflammatory response syndrome, some counterbalancing compensatory anti-inflammatory mechanisms will be activated to restore immune homeostasis. On the other hand, there remains the possibility of the integration of SARS- CoV-2 into the host genome, which potentially may cause cancer. These mechanisms have also been shown to be implicated in both tumorigenesis and metastasis. In this review, we are going to focus on potential mechanisms and the molecular interplay, which connect COVID-19, inflammation, and immune-mediated tumor progression that may propose a framework to understand the possible role of COVID-19 infection in tumorgenesis and cancer progression.

Indoleamine 2, 3-Dioxygenase 1 and CD8 Expression Profiling Revealed an Immunological Subtype of Colon Cancer With a Poor Prognosis

BACKGROUND

The Immunoscore method, based on the distribution of the quantification of cytotoxic and memory T cells, provides an indicator of tumor recurrence for colon cancer. However, recent evidence has suggested that immune checkpoint expression represents a surrogate measure of tumor-infiltrating T cell exhaustion, and therefore may serve as a more accurate prognostic biomarker for colon cancer. Indoleamine 2, 3-dioxygenase 1 (IDO1), a potent immunosuppressive molecule, has been strongly associated with T-cell infiltration, but it lacks universal prognostic significance among all of the cancer subtypes. Our aim was to elucidate the prognostic significance of the combination of IDO1 and CD8A expression in colon cancer.

METHODS

Gene expression and clinical survival data were analyzed using The Cancer Genome Atlas (TCGA) data set and validated using NCBI Gene Expression Omnibus (NCBI-GEO) cohort. Hierarchical clustering, functional enrichment analyses, and immune infiltration analysis were applied to evaluate the distinctive immune statuses in colon cancer risk subgroups stratified by IDO1 and CD8A expression. Moreover, Multivariate Cox regression analysis and Receiver Operating Characteristic (ROC) analyses were conducted to determine the prognostic value of IDO1/CD8A stratification. The IDO1/CD8A classifier may be suitable for use in the prediction of cancer development. It was validated via an in vivo murine model.

RESULTS

The stratification analysis demonstrated that the colon cancer subtype with the CD8AhighIDO1high* tumor resulted in the worst survival despite high levels of CD8 infiltrates. Its poor prognosis was associated with high levels of immune response, checkpoint genes, and Th1/IFN-γ gene signatures, regardless of CMS classification. Moreover, the IDO1/CD8A stratification was identified as an independent prognostic factor of overall survival (OS) and a useful predictive biomarker in colon cancer. In vivo data revealed the CD8AhighIDO1high group showed strong correlations with late-stage metastasis of colon carcinoma cells and upregulation of immune checkpoints.

CONCLUSIONS

The findings indicate that the proposed IDO1/CD8A stratification has exact and independent prognostic implications beyond CD8 T cell alone and CMS classification. As a result, it may represent a promising tool for risk stratification in colon cancer and improve the development of immunotherapies for patients with colon cancer in the future.

Long Noncoding RNAs, New Critical Regulators in Cancer Immunity

Long noncoding RNAs (lncRNAs) play crucial roles in various aspects of cellular functions. Recent studies have revealed that lncRNAs are critical players in the immune system by modulating immune cell differentiation and functions, particularly in cancer immunity. Here we systematically summarize how lncRNAs are involved in different processes of the cancer immunity cycle, including immune cell differentiation, proliferation, trafficking, and infiltration. Moreover, the limitations of the current understanding of lncRNA’s functions in cancer immunity are described, such as the complexity of the cancer immunity system, the inclusive functions of lncRNAs in this system, and the associated immune response. In sum, the comprehensive investigation of the roles of lncRNAs in cancer immunity aids in cancer diagnosis and therapies.

Non-viral nano-immunotherapeutics targeting tumor microenvironmental immune cells

The tumor microenvironmental immune cells (TMICs) consists of myeloid cells (tumor-associated macrophages, dendritic cells, myeloid-derived suppressor cells, etc.) and lymphocytes (T cells and B cells), all of which could be immunologically suppressed through their interactions with cancer cells. Immunological understanding of the tumor microenvironment (TME) has led to great success in the development of clinical cancer immunotherapeutic. The most advanced cancer immunotherapies are chimeric antigen receptor-modified T cells (CAR-T cells) and checkpoint inhibiting antibodies blocking CTLA4, PD-1 and PD-L1. However, many hurdles remain that should be addressed for improved therapeutic efficacy and reduced side effects such as cytokine release syndrome and patient-death. In recent decades, nanoparticles have been demonstrated as an efficient drug delivery tool due to their ease of modification, biocompatibility and intrinsic tumor targeting effect, and also been applied for cancer immunotherapy. In this review, we briefly introduce the immunosuppressive functions of TMICs and review recent advances in the development of TMIC-targeted nanotherapeutics for cancer immunotherapy. Tumor-associated macrophage (TAM)-targeted systems have shown to deplete or repolarize macrophages to M1 state for anti-tumoral immune responses. Tumor-infiltrating T cell (TIT)-targeted strategies have provided the activation of effector T cells and suppression of regulatory T cells in tumor, overcoming the current hurdles of single regimen checkpoint inhibitors. Lastly, recent studies on dendritic cell-targeted mRNA vaccination are discussed and the future perspectives of nano-immunotherapeutic for next-generation of cancer immunotherapy is emphasized.

Exosomes derived from exhausted CD8+ T cells impaired the anticancer function of normal CD8+ T cells

BACKGROUND

Previous studies suggested that diverse cells in cancer microenvironment can interact with CD8+ T cells via exosomes. We designed this study to explore the potential interaction between exhausted CD8+ T cells and normal CD8+ T cells via exosome.

METHODS

Fluorescence activated cell sorting was used to get PD1+TIM3+/PD1-TIM3-CD8+ T cells. Exosomes from the cell culture medium were collected by ultracentrifugation. Microarrays were performed to analyse the lncRNA expression profile in exosomes.

RESULTS

Functional exhausted CD8+ T cells could secrete vast exosomes, which can be uptake by normal CD8+ T cells, and impaired their proliferation (Ki67), cell activity (CD69) and the production of cytokines such as interferon-γ and interleukin-2. Microarray detection identified 257 candidate lncRNAs differently expressed in exosomes derived from exhausted CD8+ T cells and non-exhausted CD8+ T cells. Functional enrichment analysis indicated that these lncRNAs actively participated in the regulation of diverse process of CD8+ T cell activity, like metabolism, gene expression, biosynthetic process and so forth.

CONCLUSIONS

The exosomes derived from exhausted CD8+ T cells could be uptake by non-exhausted CD8+ T cells and subsequently impaired the function of receipt cells. Exosomes secreted from exhausted CD8+ T cells have distinct lncRNA expression profiles which are significantly different from those in exosomes secreted by non-exhausted CD8+ T cells.

Genetic and phenotypic difference in CD8+ T cell exhaustion between chronic hepatitis B infection and hepatocellular carcinoma

BACKGROUND

Several recent studies published have suggested that T cell exhaustion exists both in chronic infection and cancer. However, to date, few studies have investigated their differences. Here we designed this study to explore the genetic and phenotypic difference in CD8⁺ T cell exhaustion between chronic hepatitis B (CHB) and hepatocellular carcinoma (HCC).

METHODS

In this study, we assayed the phenotypes and functional states of CD8⁺ T cells separating from human CHB tissues and HCC tissues, and re-analyse the single-cell sequencing data (GSE98638) published previously. Clustering analysis of genes was performed using the T cell exhaustion gene modules (modules 1-4) proposed by Speiseret al.

RESULTS

CD8⁺ T cells from liver tissues of both CHB and HCC showed high levels of exhaustion markers, DOI: programmed cell death-1 (PD-1), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and lymphocyte-activation gene 3 (LAG-3), decreased proliferation (Ki67) and cell activity (CD69), and reduced production of effector cytokines (interferon-γ, interleukin-2 and tumour necrosis factor-α). Compared with CD8⁺ T cells from CHB tissues, those from HCC tissue showed higher expression levels of exhaustion markers, lower levels of proliferation, cell activity and the production of effector cytokines. Cluster analysis showed that exhaustion associated genes in CHB and HCC are inclined to distribute into modules 3 while those isolated from HCC into modules 1 and 2.

CONCLUSIONS

CD8⁺ T cell exhaustion existed both in CHB and HCC, but the phenotypes, functional states and underlying mechanisms are somewhat different between the two.

Long noncoding RNAs in cancer-immunity cycle

The imbalance of immune status in cancer microenvironment plays an important role in the development and progression of cancer. Immunotherapy based on this has become an important field of cancer research in recent years. Many studies on long noncoding RNA (lncRNA) in cancer have focus on its regulation in cancer development and metastasis. Recent studies have suggested that lncRNAs play crucial roles in different phases of cancer immunity, including antigen releasing, antigen presentation, immune activation, immune cells migration, infiltrating into cancer tissues, and killing cancer cells. The functional studies of lncRNAs in cancer immuntity revealed the complicated molecular mechanisms in cancer immunity from a new point of view, which may provide novel potential targets for cancer immunotherapies. Based on the classical cancer-immunity cycle theory, we review the recent studies on the functions and mechanisms of immune-related lncRNAs in different stages of cancer immunity, to summarize the relationship between lncRNAs, and cancer immunity and to provide a framework for further research.