Potential Role of CXCL13/CXCR5 Signaling in Immune Checkpoint Inhibitor Treatment in Cancer

Immune checkpoint inhibitors (ICIs), including antibodies that target programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), or cytotoxic T lymphocyte antigen 4 (CTLA4), represent some of the most important breakthroughs in new drug development for oncology therapy from the past decade. CXC chemokine ligand 13 (CXCL13) exclusively binds CXC chemokine receptor type 5 (CXCR5), which plays a critical role in immune cell recruitment and activation and the regulation of the adaptive immune response. CXCL13 is a key molecular determinant of the formation of tertiary lymphoid structures (TLSs), which are organized aggregates of T, B, and dendritic cells that participate in the adaptive antitumor immune response. CXCL13 may also serve as a prognostic and predictive factor, and the role played by CXCL13 in some ICI-responsive tumor types has gained intense interest. This review discusses how CXCL13/CXCR5 signaling modulates cancer and immune cells to promote lymphocyte infiltration, activation by tumor antigens, and differentiation to increase the antitumor immune response. We also summarize recent preclinical and clinical evidence regarding the ICI-therapeutic implications of targeting the CXCL13/CXCR5 axis and discuss the potential role of this signaling pathway in cancer immunotherapy.

Targeting TIGIT Inhibits Bladder Cancer Metastasis Through Suppressing IL-32

Bladder cancer is a highly metastatic tumor and one of the most common malignancies originating in the urinary tract. Despite the efficacy of immune checkpoints, including programmed cell death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), the effect of immunotherapy for bladder cancer remains unsatisfactory. Therefore, it is urgent to develop new targets to expand immunotherapeutic options. In this study, we utilized single-cell sequencing to explore the cell composition of tumors and detected a subset of Treg cells with high expression of T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) and interleukin (IL)-32. The antitumor immune response was suppressed by this subset of Treg cells, while IL-32 promoted bladder cancer metastasis. Nevertheless, targeting TIGIT not only reversed immunosuppression by restoring the antitumor immune response mediated by T cells but also suppressed the secretion of IL-32 and inhibited the metastasis of bladder cancer cells. Thus, our study provided novel insights into immunosuppression in bladder cancer and highlighted TIGIT as a novel target for immunotherapy of bladder cancer. We also illustrated the mechanism of the dual effect of targeting TIGIT and revealed the metastasis-promoting effect of IL-32 in bladder cancer. Collectively, these findings raise the possibility of utilizing TIGIT as a target against bladder cancer from the bench to the bedside.

Fabrication of Methylene Blue Loaded Ovalbumin/Polypyrrole Nanoparticles for Enhanced Phototherapy-Triggered Antitumor Immune Activation

Phototherapy-triggered immunogenic cell death (ICD) hardly elicit robust antitumor immune response partially due to low antigen exposure and inefficient antigen presentation. To address these issues, we developed a novel methylene blue loaded ovalbumin/ polypyrrole nanoparticles (MB@OVA/PPY NPs) via oxidative polymerization and π-π stacking reaction. The as-prepared MB@OVA/PPY NPs with outstanding photothermal conversion efficiency (38%) and photodynamic property could be readily internalized into cytoplasm and accumulated in lysosome and mitochondria. Upon 808 nm and 660 nm laser irradiation, the MB@OVA/PPY NPs not only ablated the tumor cells by inducing local hyperthermia, but also damaged residual tumor cells by generating a large amount of reactive oxygen species (ROS), finally triggered the release of large amount of damage associated molecular patterns (DAMPs). Moreover, the MB@OVA/PPY NPs synergized with DAMPs promoted thematuration and improved antigen presentation ability of DCs in virto and vivo. This work demonstrated that the MB@OVA/PPY NPs could be used as effective nanotherapeutic agents for eliminating the solid tumor and triggering powerful antitumor immune response.

Galectin-9/TIM-3 as a Key Regulator of Immune Response in Gliomas With Chromosome 1p/19q Codeletion

Gliomas with chromosome 1p/19q codeletion were considered a specific tumor entity. This study was designed to reveal the biological function alterations tightly associated with 1p/19q codeletion in gliomas. Clinicopathological and RNA sequencing data from glioma patients were obtained from The Cancer Genome Atlas and Chinese Glioma Genome Atlas databases. Gene set variation analysis was performed to explore the differences in biological functions between glioma subgroups stratified by 1p/19q codeletion status. The abundance of immune cells in each sample was detected using the CIBERSORT analytical tool. Single-cell sequencing data from public databases were analyzed using the t-distributed stochastic neighbor embedding (t-SNE) algorithm, and the findings were verified by in vitro and in vivo experiments and patient samples.We found that the activation of immune and inflammatory responses was tightly associated with 1p/19q codeletion in gliomas. As the most important transcriptional regulator of Galectin-9 in gliomas, the expression level of CCAAT enhancer-binding protein alpha in samples with 1p/19q codeletion was significantly decreased, which led to the downregulation of the immune checkpoints Galectin-9 and TIM-3. These results were validated in three independent datasets. The t-SNE analysis showed that the loss of chromosome 19q was the main reason for the promotion of the antitumor immune response. IHC protein staining, in vitro and in vivo experiments verified the results of bioinformatics analysis. In gliomas, 1p/19q codeletion can promote the antitumor immune response by downregulating the expression levels of the immune checkpoint TIM-3 and its ligand Galectin-9.

Recombinant adeno-associated viruses as a gene delivery vehicle for the use in molecular medicine

Breast cancer (BC) is a cancer with a high prevalence and mortality among women worldwide. With the current diagnostics methods, BC may remain undetected at its early stages, and the therapies developed for the disease are associated with severe side effects. Oncolytic viruses can be the basis of the new, effective BC treatment approaches. The viruses destroy tumor cells directly and launch the antitumor immune response; this dual action supports their efficacy. It is possible to make the oncolytic virus therapy more effective by designing genetically modified viruses that can target BC cells better and/or induce a stronger antitumor immune response. This review outlines the directions of development of oncolytic viruses in BC treatment, covers the optimal ways of delivering viruses to the tumor and the efficacy of their use in combination with other therapeutic agents (methods) and presents the prospects of using oncolytic viruses in antitumor vaccines.

Metformin Downregulates PD-L1 Expression in Esophageal Squamous Cell Catrcinoma by Inhibiting IL-6 Signaling Pathway

PurposeTo characterize the mechanism by which metformin inhibits PD-L1 expression in esophageal squamous cell carcinoma (ESCC) and to evaluate the effect of metformin on the antitumor immune response.MethodsThe Cancer Genome Atlas (TCGA) database was used to analyze the correlations between IL-6 and prognosis and between IL-6 and PD-L1 gene expression in esophageal cancer. Reverse transcription-quantitative polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence were used to study the mechanism by which metformin affects PD-L1 expression. Additionally, T cell function was assessed in a coculture system containing ESCC cells and peripheral blood mononuclear cells (PBMCs) treated with metformin or IL-6. In an in vivo assay, we used a model established with NPIdKO™ mice, which have a reconstituted immune system generated by transplanting PBMCs through intravenous injection, to evaluate the effect of metformin on tumors.ResultsThe TCGA esophageal cancer data showed that IL-6 expression was positively correlated with PD-L1 expression and that patients with high IL-6 expression had a significantly lower overall survival rate than patients with low IL-6 expression. PD-L1 expression in ESCC cell lines was significantly inhibited by metformin via the IL-6/JAK2/STAT3 signaling pathway but was not correlated with the canonical AMPK pathway. In the coculture system, the metformin pretreatment group showed higher T cell activation and better T cell killing function than the control group. Animal experiments confirmed that metformin downregulated PD-L1 expression and that combination treatment with metformin and PD-1 inhibitors synergistically enhanced the antitumor response.ConclusionsMetformin downregulated PD-L1 expression by blocking the IL-6/JAK2/STAT3 signaling pathway in ESCC, which enhanced the antitumor immune response.

The relationship of GITR, Lag-3 and PD-1 expression with the main indicators of systemic and local immunity in patients with breast cancer

Background. To enhance the antitumor immune response, new promising methods of immunotherapy are being developed. They consist in the blockade and activation of immune check-point molecules, in particular, the blockade of the Lag‐3 molecule (lymphocyte-activation gene 3) and the activation of the GITR receptor (Glucocorticoid induced TNF receptor). In the studies of combined use with PD-1 blockers, encouraging results were obtained, which makes the assessment of the expression of Lag-3 and GITR on immunocompetent cells of peripheral blood (PB) and tumor tissue necessary for the personalization of such treatment and understanding of the mechanisms of the antitumor immune response. Materials and methods. The study included peripheral blood samples and surgical material from 39 breast cancer patients being treated at the Blokhin National Medical Research Center of Oncology. The subpopulation composition and expression of PD-1, Lag-3, and GITR molecules were evaluated by flow cytometry. Results. The analysis of the main populations of PB lymphocytes showed that in patients with breast cancer, the content of NKT-lymphocytes was increased, and the proportions of lymphocytes expressing CD11b and CD25 markers were increased compared to the donor group. It was revealed that the tumor tissue is dominated by T-cells, an increase in the proportion of which occurs due to a reduced content of NK-lymphocytes and B-lymphocytes. The structure of Tumor-infiltrating lymphocytes (TILs) is dominated by subpopulations with immunosuppressive activity, which is indicated by a decrease in the content of CD11b+, CD25+ and perforin-positive cells, increased expression of Lag-3 and PD-1. For PB and tumor tissue, the average degree of dependence of Lag-3 expression on the content of PD-1+ lymphocytes was shown. There is an increase in the content of immunosuppressive subpopulations with high PD-1 values in PB and TILs. The direct dependence of the number of perforin-containing lymphocytes and CD11b expression on the GITR content in the PB was established, but it is not typical for breast cancer tissue. Conclusion. Since the blockade of the Lag-3 molecule by monoclonal antibodies can enhance the effect of anti-PD-1 therapy in cancer patients, it is necessary to evaluate the expression and co-expression of these two markers. A high content of GITR-positive lymphocytes in the tumor tissue, on the one hand, and a decrease in the proportion of effector subpopulations of lymphocytes, on the other, indicates the influence of the tumor microenvironment on the functioning of GITR-mediated activation of the immune response. Further investigation of GITR expression and functional activity is required to understand the nature of this contradiction.

Cancer Immunology and Immunotherapies: Mechanisms That Affect Antitumor Immune Response and Treatment Resistance

The past decade has seen immunotherapy rise to the forefront of cancer treatment [...]