Role of CD4+CD25+FOXP3+ TReg cells on tumor immunity

LncRNAs involvement in pathogenesis of immune-related disease via regulation of T regulatory cells, an updated review

The pathophysiology of several illnesses, including cancer and autoimmune diseasesdepends on human regulatory T cells (Tregs), and abnormalities in these cells may function as triggers for these conditions. Cancer and autoimmune, and gynecological diseases are associated with the differentiation of the proinflammatory T cell subset TH17 and its balance with the production of Treg. Recently, long non-coding RNAs (lncRNAs) have become important regulatory molecules in a wide range of illnesses. During epigenetic regulation, they can control the expression of important genes at several levels by affecting transcription, post-transcriptional actions, translation, and protein modification. They might connect with different molecules, such as proteins, DNA and RNA, and their structural composition is intricate. Because lncRNAs regulatebiological processes, including cell division, death, and growth, they are linked to severaldiseases. A notable instance of this is the lncRNA NEAT1, which has been the subject of several investigations to ascertain its function in immune cell development. In the context of immune cell development, several additional lncRNAs have been connected to Treg cell differentiation. In this work, we summarize current findings about the diverse functions of lncRNAs in Treg cell differentiation and control of the Th17/Treg homeostasis in autoimmune disorders, cancers, as well as several gynecological diseases where Tregs are key players.

RNA-binding protein HuR reprograms immune T cells and promotes oral squamous cell carcinoma

Hu Antigen R, also known as ELAVL1 (HuR), is a key posttranscriptional regulator in eukaryotic cells. HuR overexpression promotes several malignancies, including head and neck squamous cell carcinoma (HNSCC). However, its immune dysfunction-associated tumorigenesis pathways remain unknown. We examined HuR's effects on oral malignancies and immune cell function in vitro and in vivo using oral carcinoma cells and transgenic HuR knockout (KO) mice. CRISPR/Cas9-mediated HuR deletion in mice syngeneic oral cancer cells eliminated colony formation and tumor development. HuR-KO tumors had a lower tumor volume, fewer CD4+CD25+FoxP3+ regulatory T cells, and more CD8+ T cells, suggesting that HuR may suppress the immune response during oral cancer progression. In contrast, HuR KO oral epithelial tissues are resistant to 4NQO-induced oral malignancies compared to control tumor-bearing mice. HuR KO mice showed fewer Tregs and greater IFN levels than WT tumor-bearing mice, suggesting anticancer activity. Finally, the HuR inhibitor pyrvinium pamoate lowers tumor burden by enhancing CD8+ infiltration at the expense of CD4+, suggesting anticancer benefits. Thus, HuR-dependent oral neoplasia relies on immunological dysfunction, suggesting that decreasing HuR may boost antitumor potential and offer a novel HNSCC therapy.

A phase II study to evaluate the safety and efficacy of anlotinib combined with toripalimab for advanced biliary tract cancer

Objectives

To assess the safety and efficacy of anlotinib (a multi-targeted tyrosine kinase inhibitor) combined with toripalimab (a PD-1 monoclonal antibody) in the treatment of unresectable biliary tract cancer (BTC).

Methods

In this prospective, single-arm, single-centre exploratory clinical study, patients with locally progressed or metastatic BTC were included. Patients were treated with anlotinib (12 mg, PO, QD, for 2 weeks and then stopped for a week, 21 days for a cycle) and toripalimab (240 mg, IV, Q3W). The primary endpoint of the study was the objective response rate (ORR), as defined in RECIST version 1.1 criteria.

Results

In this study, 15 BTC patients who met the criteria were enrolled. The ORR was 26.7%, the median progression-free survival (mPFS) was 8.6 months (95% CI: 2.1-15.2), the median overall survival (mOS) was 14.53 months (95% CI: 0.8-28.2) and the disease control rate (DCR) was 87.6%. A patient with hilar cholangiocarcinoma was successfully converted after three cycles of treatment and underwent surgical resection. Furthermore, patient gene sequencing revealed that STK11 was mutated more frequently in patients with poor outcomes. In addition, patients with a CD8/Foxp3 ratio > 3 had a longer survival than those with a CD8/Foxp3 ratio ≤ 3 (P = 0.0397).

Conclusions

In patients with advanced BTC, the combination of anlotinib and toripalimab demonstrated remarkable anti-tumor potential, with increased objective response rates (ORR), longer overall survival (OS) and progression-free survival (PFS). Moreover, STK11 and CD8/Foxp3 may be as biomarkers that can predict the effectiveness of targeted therapy in combination with immunotherapy.

Clinical impact of heterogeneously distributed tumor-infiltrating lymphocytes on the prognosis of colorectal cancer

Background

Tumor-infiltrating lymphocytes (TILs) exist in various malignancies, and have been viewed as a promising biomarker to predict the efficacy and outcome of treatment. However, the marked inter- and intra-tumor heterogeneity of TILs has resulted in some confusion regarding their impact on the prognosis of colorectal cancer (CRC).

Methods

In this study, 78 CRC patients were enrolled and the CD3+ and CD8+ TILs densities at the tumor center (TC), the invasive margin (IM) and the tumor stroma (TS) were assessed by immunohistochemical staining. Their associations with clinicopathological features and progression free survival (PFS) were analyzed to evaluate the predictive and prognostic values of TILs.

Results

TILs were mainly distributed along the invasive margin. High density of TILs in tumor center and invasive margin was associated with smaller tumor size (CD3+TILsIM), reduced tumor invasion (CD3+TILsIM), absence of lymph node metastasis (CD3+TILsIM and CD8+TILsTC), earlier stage (CD3+TILsIM and CD8+TILsIM), and lower tumor grade (CD3+TILsIM and CD8+TILsTC). However, stromal TILs were not associated with any clinicopathological features. Kaplan-Meier survival analysis revealed that high densities of TILs always correlated with prolonged patient survival. The pathological N stage, CD3+ TILsIM and CD8+ TILsTC were found to be independent prognostic indicators. Additionally, early-stage CRC patients who developed recurrence after surgery, showed a higher CD3+/CD8+ TILs ratio in invasive margin. In the present study, it was clarified that CD3+ and CD8+ TILs were heterogeneously distributed in tumor tissues of CRC. The increase in intratumoral and peritumoral TILs had been shown to be strongly predictive of improved clinical outcome. More importantly, the immune signatures enabled to stratify early-stage CRC patients with high risk of recurrence, highlighting the prognostic power of TILs.

Enhancing anti-tumor immune responses through combination therapies: epigenetic drugs and immune checkpoint inhibitors

Epigenetic mechanisms are processes that affect gene expression and cellular functions without involving changes in the DNA sequence. This abnormal or unstable expression of genes regulated by epigenetics can trigger cancer and other various diseases. The immune cells involved in anti-tumor responses and the immunogenicity of tumors may also be affected by epigenomic changes. This holds significant implications for the development and application of cancer immunotherapy, epigenetic therapy, and their combined treatments in the fight against cancer. We provide an overview of recent research literature focusing on how epigenomic changes in immune cells influence immune cell behavior and function, as well as the immunogenicity of cancer cells. And the combined utilization of epigenetic medications with immune checkpoint inhibitors that focus on immune checkpoint molecules [e.g., Programmed Death 1 (PD-1), Cytotoxic T-Lymphocyte-Associated Protein 4 (CTLA-4), T cell Immunoglobulin and Mucin Domain (TIM-3), Lymphocyte Activation Gene-3 (LAG-3)] present in immune cells and stromal cells associated with tumors. We highlight the potential of small-molecule inhibitors targeting epigenetic regulators to amplify anti-tumor immune responses. Moreover, we discuss how to leverage the intricate relationship between cancer epigenetics and cancer immunology to create treatment regimens that integrate epigenetic therapies with immunotherapies.

Dual effects of radiotherapy on tumor microenvironment and its contribution towards the development of resistance to immunotherapy in gastrointestinal and thoracic cancers

Successful clinical methods for tumor elimination include a combination of surgical resection, radiotherapy, and chemotherapy. Radiotherapy is one of the crucial components of the cancer treatment regimens which allow to extend patient life expectancy. Current cutting-edge radiotherapy research is focused on the identification of methods that should increase cancer cell sensitivity to radiation and activate anti-cancer immunity mechanisms. Radiation treatment activates various cells of the tumor microenvironment (TME) and impacts tumor growth, angiogenesis, and anti-cancer immunity. Radiotherapy was shown to regulate signaling and anti-cancer functions of various TME immune and vasculature cell components, including tumor-associated macrophages, dendritic cells, endothelial cells, cancer-associated fibroblasts (CAFs), natural killers, and other T cell subsets. Dual effects of radiation, including metastasis-promoting effects and activation of oxidative stress, have been detected, suggesting that radiotherapy triggers heterogeneous targets. In this review, we critically discuss the activation of TME and angiogenesis during radiotherapy which is used to strengthen the effects of novel immunotherapy. Intracellular, genetic, and epigenetic mechanisms of signaling and clinical manipulations of immune responses and oxidative stress by radiotherapy are accented. Current findings indicate that radiotherapy should be considered as a supporting instrument for immunotherapy to limit the cancer-promoting effects of TME. To increase cancer-free survival rates, it is recommended to combine personalized radiation therapy methods with TME-targeting drugs, including immune checkpoint inhibitors.

Rubiginosin B selectively inhibits Treg cell differentiation and enhances anti-tumor immune responses by targeting calcineurin-NFAT signaling pathway

BACKGROUND

The accumulation of CD4⁺Foxp3⁺ regulatory T cells (Tregs) in the tumor microenvironment (TME) dampens anti-tumor immune responses and promotes tumor progression. Therefore, the elimination of Tregs has become a strategy to enhance the efficacy of tumor immunotherapy, although it is still a daunting challenge. Rhododendron brachypodum (R. brachypodum) is a perennial shrub mainly distributed in Southwestern China, whereas the chemical constituents in this plant remain elusive.

PURPOSE

To identify small-molecule inhibitors of Tregs from R. brachypodum.

METHODS

Meroterpenoids in R. brachypodum were isolated by column chromatography under the guidance of LCMS analyses. The structures of isolates were identified by spectroscopic data and quantum calculations. The activities of compounds were first evaluated on CD4⁺ T cell differentiation by flow cytometry in Th1, Th2, Th17, and Treg polarizing conditions, and then on CT26 and MC38 murine colorectal carcinoma cells-allografted mice models. The mechanism of action was first investigated by determining Foxp3 degradation in Jurkat T cells transfected with pLVX-TetOne-Puro-Foxp3-tGFP, and then through analyses of Foxp3 expression on several pre-transcriptional signaling molecules.

RESULTS

Two new prenylated phenolic acids (1 and 2) and a chromane meroterpenoid, rubiginosin B (RGB, 3) were obtained from R. brachypodum. The structure of S-anthopogochromene C (1) was rectified according to the electronic circular dichroism (ECD) experiment, and rhodobrachypodic acid (2) was proposed as the precursor of RGB by photochemical transformation. In this investigation, we first found that RGB (3) selectively suppressed the de novo differentiation of TGFβ-induced CD4⁺Foxp3⁺ regulatory T cells (iTregs), overcome the immunosuppressive TME, and consequently inhibited the growth of tumor in mouse models. The mechanistic study revealed that RGB could target calcineurin, inhibited the nuclear factor of activated T cells (NFAT) dephosphorylation, and down-regulated Foxp3 expression. The hypothetical binding modes of RGB with calcineurin were predicted by molecular docking, and the interactions were mainly hydrophobic effects and hydrogen bonds.

CONCLUSION

These results suggest that RGB enhances anti-tumor immune responses by inhibiting Treg cell differentiation through calcineurin-NFAT signaling pathway, and therefore RGB or its analogs may be used as adjuvant agents meriting further investigation.

Chelerythrine, a novel small molecule targeting IL-2, inhibits melanoma progression by blocking the interaction between IL-2 and its receptor

AIMS

In this study, we investigated the inhibition of IL-2 activity and anticancer efficacy of chelerythrine (CHE), a natural small molecule that targets IL-2 and inhibits CD25 binding, and elucidated the mechanism underlying the action of CHE on immune cells.

MAIN METHODS

CHE was discovered by competitive binding ELISA and SPR analysis. The effect of CHE on IL-2 activity was evaluated in CTLL-2, HEK-Blue reporter and immune cells, and in ex vivo generation of regulatory T cells (Treg cells). The antitumor activity of CHE was evaluated in B16F10 tumor-bearing C57BL/6 or BALB/c nude mice.

KEY FINDINGS

We identified that CHE, which acts as an IL-2 inhibitor, selectively inhibits the interaction between IL-2 and IL-2Rα and directly binds to IL-2. CHE inhibited the proliferation and signaling of CTLL-2 cells and suppressed IL-2 activity in HEK-Blue reporter and immune cells. CHE prevented the conversion of naive CD4⁺ T cells into CD4⁺CD25⁺Foxp3⁺ Treg cells in response to IL-2. CHE reduced tumor growth in C57BL/6 mice but not in T-cell-deficient mice, upregulated the expression of IFN-γ and cytotoxic molecules, and limited Foxp3 expression. Furthermore, the combination of CHE and a PD-1 inhibitor synergistically increased antitumor activity in melanoma-bearing mice and almost completely regressed the implanted tumors.

SIGNIFICANCE

We found that CHE, which targets IL-2 and inhibits its binding to CD25, exhibits T cell-mediated antitumor activity and that combination therapy with CHE and PD-1 inhibitor induced synergistic antitumor effects, suggesting that CHE may be a promising anticancer agent for melanoma monotherapy and combination therapy.

The soldiers needed to be awakened: Tumor-infiltrating immune cells

In the tumor microenvironment, tumor-infiltrating immune cells (TIICs) are a key component. Different types of TIICs play distinct roles. CD8+ T cells and natural killer (NK) cells could secrete soluble factors to hinder tumor cell growth, whereas regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) release inhibitory factors to promote tumor growth and progression. In the meantime, a growing body of evidence illustrates that the balance between pro- and anti-tumor responses of TIICs is associated with the prognosis in the tumor microenvironment. Therefore, in order to boost anti-tumor response and improve the clinical outcome of tumor patients, a variety of anti-tumor strategies for targeting TIICs based on their respective functions have been developed and obtained good treatment benefits, including mainly immune checkpoint blockade (ICB), adoptive cell therapies (ACT), chimeric antigen receptor (CAR) T cells, and various monoclonal antibodies. In recent years, the tumor-specific features of immune cells are further investigated by various methods, such as using single-cell RNA sequencing (scRNA-seq), and the results indicate that these cells have diverse phenotypes in different types of tumors and emerge inconsistent therapeutic responses. Hence, we concluded the recent advances in tumor-infiltrating immune cells, including functions, prognostic values, and various immunotherapy strategies for each immune cell in different tumors.

INSC Is a Prognosis-Associated Biomarker Involved in Tumor Immune Infiltration in Colon Adenocarcinoma

Aims. The purpose of this study was to investigate the correlation of INSC gene with the level of immune infiltration and clinical prognosis in colon adenocarcinoma (COAD) patients. Materials and Methods. INSC expression profile data and clinicopathological information of COAD patients were downloaded from TCGA. Xiantao bioinformatics tool was used to analyze the expression of INSC between the COAD group and the normal control group, and GEPIA2 was used to analyze the top 100 coexpressed genes. Logistic regression analysis was performed to assess the relationship between clinicopathological features and INSC. The Kaplan-Meier method and Cox regression model were used to perform the survival analysis. CIBERSORT algorithm was used to analyze the relationship between INSC expression and immune infiltration cells. Results. The expression level of INSC in COAD was significantly downregulated. The result of logistic regression analysis confirmed that tumor stage was the final influencing factor of INSC expression. The overall survival rate of INSC in the high expression group was higher than that of the low expression group, and it was an independent risk factor of prognosis. Enrichment results indicated that INSC was enriched in the regulation of T-helper 2 cell differentiation pathway. Immune infiltration analysis showed that INSC expression was positively correlated with the B cell plasma, T cell CD4+ memory resting, activated myeloid dendritic cells, and eosinophils. Conclusions. Our study found that the expression of INSC was significantly downregulated in COAD, which regulated immune-infiltrating cells during cancer development and was associated with malignant progression in COAD patients.