Breast cancer-induced immune suppression in the sentinel lymph node is effectively countered by CpG-B in conjunction with inhibition of the JAK2/STAT3 pathway

The Applications of ELISpot in the Identification and Treatment of Various Forms of Tuberculosis and in the Cancer Immunotherapies

ELISpot (enzyme-linked immunospot) is a powerful immunological tool for the detection of cytokine-secreting cells at a single-cell resolution. It is widely used for the diagnosis of various infectious diseases, e.g., tuberculosis and sarcoidosis, and it is also widely used in cancer immunotherapy research. Its ability to distinguish between active and latent forms of tuberculosis makes it an extremely powerful tool for epidemiological studies and contact tracing. In addition to that, it is a very useful tool for the research and development of cancer immunotherapies. ELISpot can be employed to assess the immune responses against various tumor-associated antigens, which could provide valuable insights for the development of effective therapies against cancers. Furthermore, it plays a crucial role to the evaluation of immune responses against specific antigens that not only could aid in vaccine development but also assist in treatment monitoring and development of therapeutic and diagnostic strategies. This chapter briefly describes some of the applications of ELISpot in tuberculosis and cancer research.

Local delivery of low-dose anti–CTLA-4 to the melanoma lymphatic basin leads to systemic T reg reduction and effector T cell activation

Preclinical studies show that locoregional CTLA-4 blockade is equally effective in inducing tumor eradication as systemic delivery, without the added risk of immune-related side effects. This efficacy is related to access of the CTLA-4 blocking antibodies to tumor-draining lymph nodes (TDLNs). Local delivery of anti–CTLA-4 after surgical removal of primary melanoma, before sentinel lymph node biopsy (SLNB), provides a unique setting to clinically assess the role of TDLN in the biological efficacy of locoregional CTLA-4 blockade. Here, we have evaluated the safety, tolerability, and immunomodulatory effects in the SLN and peripheral blood of a single dose of tremelimumab [a fully human immunoglobulin gamma-2 (IgG2) mAb directed against CTLA-4] in a dose range of 2 to 20 mg, injected intradermally at the tumor excision site 1 week before SLNB in 13 patients with early-stage melanoma (phase 1 trial; NCT04274816). Intradermal delivery was safe and well tolerated and induced activation of migratory dendritic cell (DC) subsets in the SLN. It also induced profound and durable decreases in regulatory T cell (T reg ) frequencies and activation of effector T cells in both SLN and peripheral blood. Moreover, systemic T cell responses against NY-ESO-1 or MART-1 were primed or boosted ( N = 7), in association with T cell activation and central memory T cell differentiation. These findings indicate that local administration of anti–CTLA-4 may offer a safe and promising adjuvant treatment strategy for patients with early-stage melanoma. Moreover, our data demonstrate a central role for TDLN in the biological efficacy of CTLA-4 blockade and support TDLN-targeted delivery methods.

At the Crossroads of Molecular Biology and Immunology: Molecular Pathways for Immunological Targeting of Head and Neck Squamous Cell Carcinoma

Background: Recent advances in immunotherapy for head and neck squamous cell carcinoma (HNSCC) have led to implementation of anti-programmed death receptor 1 (PD-1) immunotherapy to standard of care for recurrent/metastatic HNSCC. However, the majority of tumors do not respond to these therapies, indicating that these tumors are not immunogenic or other immunosuppressive mechanisms might be at play. Aim: Given their role in carcinogenesis as well as in immune modulation, we discuss the relation between the STAT3, PI3K/AKT/mTOR and Wnt signaling pathways to identify potential targets to empower the immune response against HNSCC. Results: We focused on three pathways. First, STAT3 is often overactivated in HNSCC and induces the secretion of immunosuppressive cytokines, thereby promoting recruitment of immune suppressive regulatory T cells and myeloid-derived suppressor cells to the tumor microenvironment (TME) while hampering the development of dendritic cells. Second, PI3K/AKT/mTOR mutational activation results in increased tumor proliferation but could also be important in HNSCC immune evasion due to the downregulation of components in the antigen-processing machinery. Third, canonical Wnt signaling is overactivated in >20% of HNSCC and could be an interesting pleotropic target since it is related to increased tumor cell proliferation and the development of an immunosuppressive HNSCC TME. Conclusion: The molecular pathology of HNSCC is complex and heterogeneous, varying between sites and disease etiology (i.e., HPV). The in HNSCC widely affected signaling pathways STAT3, PI3K/AKT/mTOR and Wnt are implicated in some of the very mechanisms underlying immune evasion of HNSCC, thereby representing promising targets to possibly facilitate immunotherapy response.

Cyy260, a novel small molecule inhibitor, suppresses non-small cell lung cancer cell growth via JAK2/STAT3 pathway

Non-small cell lung cancer (NSCLC) is a malignant tumor that accounts for the most new cancer cases and cancer-related deaths worldwide, and the proliferation and metastasis of NSCLC are the main reasons for treatment failure and patient death. Traditional chemotherapeutic drugs have low selectivity, which can kill cancer cells and cause damage to normal cells at the same time. Therefore, it is particularly important to study therapies that target cancer cells and to find low-toxicity, high-efficiency anticancer drugs. Cyy260 is a novel small molecule inhibitor that we synthesized for the first time. Here, we investigated the in vitro and in vivo antitumor activities of Cyy260 and explored the underlying mechanisms in NSCLC. Cyy260 had a concentration- and time-dependent inhibitory effect on NSCLC cells, but it was less toxic to normal cells. Cyy260 regulated apoptosis through intracellular and extracellular apoptotic pathways. In addition, Cyy260 could also induce cell cycle arrest, thereby inhibiting cell proliferation. Further analysis of molecular mechanisms showed that the JAK2/STAT3 signaling pathway was involved in the antitumor effect mediated by Cyy260. Analysis of subcutaneously transplanted tumors in mice showed that Cyy260 suppressed tumor growth in vivo. Our results proved that Cyy260 is a novel inhibitor of the JAK2/STAT3 pathway thus may have potential in therapy of NSCLC and other cancers.

Cyclin D1b induces changes in the macrophage phenotype resulting in promotion of tumor metastasis

In breast cancer, tumor-associated macrophages with activated phenotypes promote tumor invasion and metastasis. The more aggressive mesenchymal-like breast cancer cells have a selective advantage, skewing macrophages toward the more immunosuppressive subtype. However, the mechanism underlying this shift is poorly understood. Cyclin D1b is a highly oncogenic variant of cyclin D1. Our previous study showed that non-metastatic epithelial-like breast cancer cells were highly metastatic in vivo when cyclin D1b was overexpressed. The present study determined whether cyclin D1b contributed to the interaction between breast cancer cells and macrophages. The results showed that cyclin D1b promoted the invasion of breast cancer cells in vitro. Specifically, through overexpression of cyclin D1b, breast cancer cells regulated the differentiation of macrophages into a more immunosuppressive M2 phenotype. Notably, tumor cells overexpressing cyclin D1b activated macrophages and induced migration of breast cancer cells. Further investigations indicated that SDF-1 mediated macrophage activation through breast cancer cells overexpressing cyclin D1b. These results revealed a previously unknown link between aggressive breast cancer cells and Tumor-associated macrophages, and highlighted the importance of cyclin D1b activity in the breast cancer microenvironment.

Immune Characters and Plasticity of the Sentinel Lymph Node in Colorectal Cancer Patients

Purpose

This study is aimed at immunologically characterizing sentinel lymph nodes (SNs) in colorectal cancer (CRC) patients and identifying changes in immunological phenotype and function of SNs isolated from the tumor immunosuppressive microenvironment.

Methods

A total of 53 pairs of matched SNs and non-SNs (NSNs) were collected by using a lymph node tracer dye. Flow cytometry was performed to detect the immunophenotype of T cells as well as the expression of activation and inhibitory markers. Differential expression and distribution of characteristic immune cell markers were analyzed by multiplex immunohistochemistry (mIHC). Transcriptomics analysis was conducted to compare the differences in the expression of immune-related genes among lymph nodes. The ex vivo culture of lymph nodes was carried out to examine changes in immunological phenotypes and functions.

Results

Compared with NSNs, SNs harbored a significantly higher percentage of regulatory T cells (Tregs) but a lower proportion of MoMDSCs. As indicated in the mIHC assays, Tregs, T follicular helper (Tfh) cells, and M2 macrophages were mainly distributed in cortical areas, germinal centers, and subcapsular sinus areas, respectively, while significantly higher numbers of Tregs and Tfh cells were detected in SNs as compared to NSNs. Moreover, GSEA revealed that T cell activation genes and CD8+ T cell exhaustion-related genes are enriched in SNs and NSNs, respectively. The ex vivo culture led to an increase in the proportion of CD4+ cells, while activating T cells in SNs. In addition, SNs displayed a higher increase in the expression of cytokines IFN-γ, TNF-α, and sFas than NSNs.

Conclusion

SNs are shown to be in an immune active state in vivo, while highly expressing inhibitory cytokines and suppressive markers. The ex vivo culture enhanced antitumor immunological function of SN-T cells, providing a starting material for adoptive cell therapy for CRC.

CpG-Based Nanovaccines for Cancer Immunotherapy

Cancer has been a serious health hazard to the people all over the world with its high incidence and horrible mortality. In recent years, tumor vaccines in immunotherapy have become a hotspot in cancer therapy due to their many practical advantages and good therapeutic potentials. Among the various vaccines, nanovaccine utilized nanoparticles (NPs) as the carrier and/or adjuvant has presented significant therapeutic effect in cancer treatment. For tumor nanovaccines, unmethylated cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN) is a commonly used adjuvant. It has been reported that CpG ODN was the most effective immune stimulant among the currently known adjuvants. It could be recognized by toll-like receptor 9 (TLR9) to activate humoral and cellular immunity for preventing or treating cancer. In this review, the topic of CpG-based nanovaccines for cancer immunotherapy will be focused. The types and properties of different CpG will be introduced in detail first, and then some representative tumor nanovaccines will be reviewed according to the diverse loading modes of CpG, such as electrostatic adsorption, covalent bonding, hydrophilic and hydrophobic interaction, and DNA self-assembly, for summarizing the current progress of CpG-based tumor nanovaccines. Finally, the challenges and future perspectives will be discussed. It is hoped that this review will provide valuable references for the development of nanovaccines in cancer immunotherapy.

Coordinated regulation of immune contexture: crosstalk between STAT3 and immune cells during breast cancer progression

Recent insights into the molecular and cellular mechanisms underlying cancer development have revealed the tumor microenvironment (TME) immune cells to functionally affect the development and progression of breast cancer. However, insufficient evidence of TME immune modulators limit the clinical application of immunotherapy for advanced and metastatic breast cancers. Intercellular STAT3 activation of immune cells plays a central role in breast cancer TME immunosuppression and distant metastasis. Accumulating evidence suggests that targeting STAT3 and/or in combination with radiotherapy may enhance anti-cancer immune responses and rescue the systemic immunologic microenvironment in breast cancer. Indeed, apart from its oncogenic role in tumor cells, the functions of STAT3 in TME of breast cancer involve multiple types of immunosuppression and is associated with tumor cell metastasis. In this review, we summarize the available information on the functions of STAT3-related immune cells in TME of breast cancer, as well as the specific upstream and downstream targets. Additionally, we provide insights about the potential immunosuppression mechanisms of each type of evaluated immune cells. Video abstract.

Immunotherapy Goes Local: The Central Role of Lymph Nodes in Driving Tumor Infiltration and Efficacy

Immune checkpoint blockade (ICB) has changed the therapeutic landscape of oncology but its impact is limited by primary or secondary resistance. ICB resistance has been related to a lack of T cells infiltrating into the tumor. Strategies to overcome this hurdle have so far focused on the tumor microenvironment, but have mostly overlooked the role of tumor-draining lymph nodes (TDLN). Whereas for CTLA-4 blockade TDLN have long since been implicated due to its perceived mechanism-of-action involving T cell priming, only recently has evidence been emerging showing TDLN to be vital for the efficacy of PD-1 blockade as well. TDLN are targeted by developing tumors to create an immune suppressed pre-metastatic niche which can lead to priming of dysfunctional antitumor T cells. In this review, we will discuss the evidence that therapeutic targeting of TDLN may ensure sufficient antitumor T cell activation and subsequent tumor infiltration to facilitate effective ICB. Indeed, waves of tumor-specific, proliferating stem cell-like, or progenitor exhausted T cells, either newly primed or reinvigorated in TDLN, are vital for PD-1 blockade efficacy. Both tumor-derived migratory dendritic cell (DC) subsets and DC subsets residing in TDLN, and an interplay between them, have been implicated in the induction of these T cells, their imprinting for homing and subsequent tumor control. We propose that therapeutic approaches, involving local delivery of immune modulatory agents for optimal access to TDLN, aimed at overcoming hampered DC activation, will enable ICB by promoting T cell recruitment to the tumor, both in early and in advanced stages of cancer.

Modulating the Tumour Microenvironment by Intratumoural Injection of Pattern Recognition Receptor Agonists

Signalling through pattern recognition receptors (PRRs) leads to strong proinflammatory responses, enhancing the activity of antigen presenting cells and shaping adaptive immune responses against tumour associated antigens. Unfortunately, toxicities associated with systemic administration of these agonists have limited their clinical use to date. Direct injection of PRR agonists into the tumour can enhance immune responses by directly modulating the cells present in the tumour microenvironment. This can improve local antitumour activity, but importantly, also facilitates systemic responses that limit tumour growth at distant sites. As such, this form of therapy could be used clinically where metastatic tumour lesions are accessible, or as neoadjuvant therapy. In this review, we summarise current preclinical data on intratumoural administration of PRR agonists, including new strategies to optimise delivery and impact, and combination studies with current and promising new cancer therapies.