T-cell immunoglobulin and ITIM domain in cancer immunotherapy: A focus on tumor-infiltrating regulatory T cells

Targeting the Immune Microenvironment in Chronic Lymphocytic Leukemia: An Evolving Therapeutic Strategy

Although small molecule inhibitors that target the aberrant signaling pathways and molecular defects of chronic lymphocytic leukemia (CLL) result in improved survival benefits vs. traditional chemoimmunotherapy or chemotherapy, treatment resistance may result later, reflecting the intrinsic tumor heterogeneity, persistence of the leukemic clone, and presence of the tumor microenvironment, which supports the survival of the disease clone. Patients with CLL have immune-related abnormalities in T lymphocyte subset composition, immune synapse formation, and other immune dysregulations. Cellular interactions between the disease clone and its microenvironment provide therapeutic opportunities to target these tumor pathogenesis pathways, potentially improving the patient's immune functions and clinical outcomes of targeted therapies. At present, despite the lack of response of immune checkpoint inhibitors in CLL, they showed promising efficacy in patients with Richter transformation. Together with CD19-targeted chimeric antigen receptor-modified T cell (CAR-T) therapy, novel bispecific antibodies and other immunotherapies are being investigated to improve survival outcomes for patients with relapsed or refractory (R/R) CLL, as exemplified by epcoritamab, a bispecific antibody that recently demonstrated initial efficacy in R/R CLL and in patients in high-risk CLL subgroups, including those with TP53 aberrations and unmutated genes that encode immunoglobulin variable heavy chain region (IGHV). Furthermore, to address the immune escape of cancer cells and issues that impact the durability of single-targeted T cell-redirected therapies, novel strategies such as trispecific antibodies and combination therapies are being investigated to increase tumor specificity or immune cell activation. In summary, there is emerging evidence that immunotherapies may counteract the immunosuppressive microenvironment of CLL, improve clinical responses, decrease the risk of infection, and overcome treatment resistance.

Pembrolizumab in Patients of Chinese Descent with Microsatellite Instability-high/Mismatch Repair Deficient Advanced Solid Tumors: KEYNOTE-158 Final Analysis

INTRODUCTION

KEYNOTE-158 (NCT02628067) supported the US Food and Drug Administration approval of pembrolizumab for microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) advanced solid tumors. Incidence of MSI-H/dMMR tumors in patients of Chinese descent is similar to that of Western populations. Cohort L of KEYNOTE-158 evaluated pembrolizumab in patients of Chinese descent with previously treated MSI-H/dMMR tumors. We previously reported an objective response rate (ORR) of 70% in 20 patients from cohort L which supported the approval in China of pembrolizumab in patients with MSI-H/dMMR solid tumors. Here we present results of the final analysis for 30 patients with median follow-up of 18 months.

METHODS

Eligible patients who had confirmed unresectable or metastatic MSI-H/dMMR tumors, and one or more prior lines of therapy, received 200 mg pembrolizumab Q3W (up to 35 cycles) until progression, toxicity, or withdrawal. Primary endpoint was ORR per RECIST 1.1 by central review. Secondary endpoints were duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Thirty patients were enrolled; 7 (23%) were aged ≥ 65 years, and 20 (67%) were female. With median follow-up of 18 months, ORR was 66.7%. Median DOR was not reached (NR), with 12-month DOR rate of 85.9%. Median PFS was NR, with 18-month PFS rate of 63.0%. Median OS was NR, with 18-month OS rate of 78.8%. Treatment-related adverse events (AE) were reported in 22 (73%) patients. Grade 3-4 treatment-related AEs occurred in 7 (23%) patients. Immune-mediated AEs occurred in 11 (37%) patients of which 2 (7%) had grade 3 AEs. No grade ≥ 4 immune-mediated AEs occurred.

CONCLUSION

Pembrolizumab continues to provide clinically meaningful antitumor activity and durable responses with a manageable safety profile in patients of Chinese descent with MSI-H/dMMR advanced solid tumors. These results are consistent with those reported for patients in the global population and further support the use of pembrolizumab in patients of Chinese descent with MSI-H/dMMR tumors. TRIAL REGISTRATION NUMBER: NCT02628067.

Identification of m6A methyltransferase-related WTAP and ZC3H13 predicts immune infiltrates in glioblastoma

Glioblastoma (GBM) is a prevalent and highly fatal primary malignant brain tumor. N6-methyladenosine (m6A) modification plays a critical role in the development of brain tumor. WTAP and ZC3H13 have been identified across various species. Immune contexture, which includes the tumor microenvironment (TME), plays a significant role in cancer progression and treatment. This study aimed to explore the potential impact between WTAP and ZC3H13 on the immunological characteristics of GBM. We utilized data from TCGA-GBM, GEO and CGGA datasets to obtain platform and probe data. Patients with GBM were stratified into two clusters based on the expression of WTAP and ZC3H13 using consensus clustering approach. Immune infiltration within the tumor microenvironment was assessed using ESTIMATE, CIBERSORT and ssGSEA methodologies. Functional disparities were determined through gene set enrichment analysis (GSEA). Tumor mutation burden (TMB) and immune checkpoint inhibitors (ICIs) were also analyzed. Co-expression network analysis (WGCNA) was used to identify genes associated with WTAP/ZC3H13 and immunity. Validation was performed using GEO and CGGA datasets. Our analysis revealed that cluster1 exhibited higher WTAP expression but lower ZC3H13 expression compared to cluster2. Cluster1 showed higher levels of immune infiltration and TMB compared to cluster2. WGCNA identified 15 genes closely associated with WTAP/ZC3H13 expression and immune scores, notably CTLA4, CD27, ICOS, and LAG3. Our results suggested that WTAP and ZC3H13 influence on immune contexture of GBM, providing new insights into tumor immunity in GBM.

New insights into immune cells in cancer immunotherapy: from epigenetic modification, metabolic modulation to cell communication

Cancer is one of the leading causes of death worldwide, and more effective ways of attacking cancer are being sought. Cancer immunotherapy is a new and effective therapeutic method after surgery, radiotherapy, chemotherapy, and targeted therapy. Cancer immunotherapy aims to kill tumor cells by stimulating or rebuilding the body's immune system, with specific efficiency and high safety. However, only few tumor patients respond to immunotherapy and due to the complex and variable characters of cancer immune escape, the behavior and regulatory mechanisms of immune cells need to be deeply explored from more dimensions. Epigenetic modifications, metabolic modulation, and cell-to-cell communication are key factors in immune cell adaptation and response to the complex tumor microenvironment. They collectively determine the state and function of immune cells through modulating gene expression, changing in energy and nutrient demands. In addition, immune cells engage in complex communication networks with other immune components, which are mediated by exosomes, cytokines, and chemokines, and are pivotal in shaping the tumor progression and therapeutic response. Understanding the interactions and combined effects of such multidimensions mechanisms in immune cell modulation is important for revealing the mechanisms of immunotherapy failure and developing new therapeutic targets and strategies.

Targeting TIGIT for cancer immunotherapy: recent advances and future directions

As a newly identified checkpoint, T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) is highly expressed on CD4+ T cells, CD8+ T cells, natural killer (NK) cells, regulatory T cells (Tregs), and tumor-infiltrating lymphocytes (TILs). TIGIT has been associated with NK cell exhaustion in vivo and in individuals with various cancers. It not only modulates NK cell survival but also mediates T cell exhaustion. As the primary ligand of TIGIT in humans, CD155 may be the main target for immunotherapy due to its interaction with TIGIT. It has been found that the anti-programmed cell death protein 1 (PD-1) treatment response in cancer immunotherapy is correlated with CD155 but not TIGIT. Anti-TIGIT alone and in combination with anti-PD-1 agents have been tested for cancer immunotherapy. Although two clinical studies on advanced lung cancer had positive results, the TIGIT-targeted antibody, tiragolumab, recently failed in two new trials. In this review, we highlight the current developments on TIGIT for cancer immunotherapy and discuss the characteristics and functions of TIGIT.

Advanced Generation Therapeutics: Biomimetic Nanodelivery System for Tumor Immunotherapy

Tumor immunotherapy is a safe and effective strategy for precision medicine. However, immunotherapy for most cancer cases still ends in failure, with the root causes of the immunosuppressive and extraordinary heterogeneity of the solid tumors microenvironment. The emerging biomimetic nanodelivery system provides a promising tactic to improve the immunotherapy effect while reducing the adverse reactions on nontarget cells. Herein, we summarize the relationship between tumor occurrence and tumor immune microenvironment, mechanism of tumor immune escape, immunotherapy classification (including adoptive cellular therapy, cytokines, cancer vaccines, and immune checkpoint inhibitors) and recommend target cells for immunotherapy first, and then emphatically introduce the recent advances and applications of the latest biomimetic nanodelivery systems (e.g., immune cells, erythrocytes, tumor cells, platelets, bacteria) in tumor immunotherapy. Meanwhile, we separately summarize the application of tumor vaccines. Finally, the predictable challenges and perspectives in a forward exploration of biomimetic nanodelivery systems for tumor immunotherapy are also discussed.

Regulatory cells and the effect of cancer immunotherapy

Several mechanisms and cell types are involved in the regulation of the immune response. These include mostly regulatory T cells (Tregs), regulatory macrophages (Mregs), myeloid suppressor cells (MDSCs) and other regulatory cell types such as tolerogenic dendritic cells (tolDCs), regulatory B cells (Bregs), and mesenchymal stem cells (MSCs). These regulatory cells, known for their ability to suppress immune responses, can also suppress the anti-tumor immune response. The infiltration of many regulatory cells into tumor tissues is therefore associated with a poor prognosis. There is growing evidence that elimination of Tregs enhances anti-tumor immune responses. However, the systemic depletion of Treg cells can simultaneously cause deleterious autoimmunity. Furthermore, since regulatory cells are characterized by their high level of expression of immune checkpoints, it is also expected that immune checkpoint inhibitors perform part of their function by blocking these molecules and enhancing the immune response. This indicates that immunotherapy does not only act by activating specific effector T cells but can also directly or indirectly attenuate the suppressive activity of regulatory cells in tumor tissues. This review aims to draw together our current knowledge about the effect of immunotherapy on the various types of regulatory cells, and how these effects may be beneficial in the response to immunotherapy.

Comprehensive analysis of prognosis and immune function of CD70-CD27 signaling axis in pan-cancer

The immune checkpoint molecule CD70 and its receptor CD27 constitute the signal transduction axis, which is abnormally expressed in many solid tumors and is crucial for T cell co-stimulation and immune escape. Tumor cells regulate CD27 expression in the tumor microenvironment by expressing CD70, which promotes immune escape. Although current research evidence suggests a link between CD70 and tumors, no pan-cancer analysis is available. Using the Cancer Genome Atlas, Gene Expression Omnibus datasets, and online databases, we first explored the potential carcinogenic role of the CD70-CD27 signaling axis in human malignancies. Furthermore, qRT-PCR, Western blot, immunohistochemistry, and a T cell-mediated tumor cell killing assay were used to assess the biological function of the CD70-CD27 signaling axis. CD70 expression is upregulated in most cancers and has an obvious correlation with the prognosis of tumor patients. The expression of CD70 and CD27 is associated with the level of regulatory T cell (Treg) infiltration. In addition, T cell receptor signaling pathways, PI3K-AKT, NF-κB, and TNF signaling pathways are also involved in CD70-mediated immune escape. CD70 mainly regulates tumor immune escape by regulating T cell-mediated tumor killing, with Tregs possibly being its primary T cell subset. Our first pan-cancer study provides a relatively comprehensive understanding of the carcinogenic role of the CD70-CD27 signaling axis in different tumors.

Prognostic value of TIGIT in East Asian patients with solid cancers: A systematic review, meta-analysis and pancancer analysis

Background

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) participates in tumor immune escape by delivering inhibitory signals to T cells. The purpose of this article was to assess the prognostic value of TIGIT and its immunological function in solid cancers.

Methods

Three databases were searched for relevant articles. The main endpoints were overall survival (OS), progression-free survival (PFS), recurrence-free survival (RFS), and disease-free survival (DFS). Hazard ratios (HR) were pooled by using fixed-effects or random-effects models. Pancancer analysis of TIGIT was performed based on public online databases, mainly The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and UCSC Xena. The possible relationships between TIGIT expression and the tumor microenvironment (TME), infiltration of immune cells, immune-related genes, tumor mutation burden (TMB), and microsatellite instability (MSI) were revealed in this article.

Results

Sixteen studies met the inclusion criteria. High expression of TIGIT was associated with worse OS [HR= 1.73, 95% confidence interval (CI) 1.50, 1.99], PFS (HR = 1.53, 95% CI [1.25, 1.88]), RFS (HR = 2.40, 95% CI [1.97, 2.93]), and DFS (HR= 6.57, 95% CI [0.73, 59.16]) in East Asian patients with solid cancers. TIGIT expression was positively correlated with immune infiltration scores and infiltration of CD8 T lymphocytes in all of the cancers included. TIGIT was found to be coexpressed with the genes encoding immunostimulators, immunoinhibitors, chemokines, chemokine receptors, and major histocompatibility complex (MHC), especially in gastroesophageal cancer. TMB and MSI were also associated with TIGIT upregulation in diverse kinds of cancers.

Conclusion

High expression of TIGIT is associated with poorer prognosis in East Asian patients with solid cancers. TIGIT is a novel prognostic biomarker and immunotherapeutic target for various solid cancers because of its activity in cancer immunity and tumorigenesis.