Lymphocyte-polarized DC1s: Effective inducers of tumor-specific CTLs

Disfunction of communication among immune cells in minimal-deviation adenocarcinoma of the cervix as an immunotherapeutic opportunity

Minimal deviation adenocarcinoma (MDA) of the uterine cervix, also referred to as malignant adenoma, is a rare subtype of cervical adenocarcinoma that exhibits histological characteristics resembling those of benign tumors, resulting in a low diagnostic rate and a lack of effective treatment options. The transcriptomic features of MDA at the single-cell resolution and within the tumor microenvironment (TME) remain unclear. In this study, we conducted single-cell transcriptomic analyses of MDA samples (Ca) and adjacent normal tissues (PCa). The present study reveals the prevalence of dendritic cells (DCs) and T cells in the carcinoma (Ca) of mammary ductal adenocarcinoma (MDA), with DCs undergoing significant metabolic reprogramming and immune stress. Additionally, our findings demonstrate the crucial involvement of DCs and T cells in the pathogenesis and metastatic progression of MDA, as evidenced by single-cell transcriptomic profiling of MDA and HPV samples. This resource provides a more profound understanding of the indolent nature of MDA and may prove useful in the development of MDA immunotherapy.

Trial watch: TLR3 agonists in cancer therapy

Toll-like receptor 3 (TLR3) is a pattern recognition receptor that senses exogenous (viral) as well as endogenous (mammalian) double-stranded RNA in endosomes. On activation, TLR3 initiates a signal transduction pathway that culminates with the secretion of pro-inflammatory cytokines including type I interferon (IFN). The latter is essential not only for innate immune responses to infection but also for the initiation of antigen-specific immunity against viruses and malignant cells. These aspects of TLR3 biology have supported the development of various agonists for use as stand-alone agents or combined with other therapeutic modalities in cancer patients. Here, we review recent preclinical and clinical advances in the development of TLR3 agonists for oncological disorders.

Abbreviations

cDC, conventional dendritic cell; CMT, cytokine modulating treatment; CRC, colorectal carcinoma; CTL, cytotoxic T lymphocyte; DC, dendritic cell; dsRNA, double-stranded RNA; FLT3LG, fms-related receptor tyrosine kinase 3 ligand; HNSCC, head and neck squamous cell carcinoma; IFN, interferon; IL, interleukin; ISV, in situ vaccine; MUC1, mucin 1, cell surface associated; PD-1, programmed cell death 1; PD-L1, programmed death-ligand 1; polyA:U, polyadenylic:polyuridylic acid; polyI:C, polyriboinosinic:polyribocytidylic acid; TLR, Toll-like receptor.

IL-37 induces anti-tumor immunity by indirectly promoting dendritic cell recruitment and activation in hepatocellular carcinoma

Introduction

IL-37 is a cytokine of IL-1 family that plays an important role in innate immunity and inflammation, and has been studied as a tumor suppressor in many cancers. However, it remains unclear whether IL-37 plays a regulatory role in tumor-infiltrating dendritic cells (DCs) in hepatocellular carcinoma (HCC).

Materials and methods

We evaluated the relationship between IL-37 expression and tumor infiltration by DCs in 155 HCC samples through immunohistochemical analysis and Kaplan–Meier survival analysis. The effects of IL-37 on the anti-tumor activity of DCs were investigated by ELISA, flow cytometry, real-time quantitative PCR, cytotoxicity assays and tumorigenicity assays.

Results

The expression level of IL-37 in HCC samples was positively correlated with the degree of CD1a⁺ DCs infiltration. The survival rates of patients with both a high expression of IL-37 and a high infiltration by CD1a⁺ DCs were significantly higher than those of patients with a low expression of IL-37 and a low infiltration by CD1a⁺ DCs. In vitro chemotaxis analysis indicated that HCC cells overexpressing IL-37 recruited more DCs by secreting higher levels of specific chemokines (eg, CCL3 and CCL20). In addition, IL-37 indirectly up-regulated the expression of major histocompatibility class II molecules, CD86 and CD40 on DCs by acting on tumor cells; IL-37 also indirectly enhanced the anti-tumor effect of T lymphocytes by stimulating DCs to secrete cytokines such as IL-2, IL-12, IL-12p70, interferon-α (IFN-α) and IFN-γ. Finally, overexpression IL-37 in HCC cells significantly delayed tumor growth and increased recruitment of CD11c⁺ DCs to tumor tissues was also revealed in vivo mouse model.

Conclusion

DCs play an important role in IL-37 mediated anti-tumor immune responses in HCC, which may contribute to the development of novel cancer immunotherapeutic strategies.

Pathogen-Associated Molecular Patterns Induced Crosstalk between Dendritic Cells, T Helper Cells, and Natural Killer Helper Cells Can Improve Dendritic Cell Vaccination

A coordinated cellular interplay is of crucial importance in both host defense against pathogens and malignantly transformed cells. The various interactions of Dendritic Cells (DC), Natural Killer (NK) cells, and T helper (Th) cells can be influenced by a variety of pathogen-associated molecular patterns (PAMPs) and will lead to enhanced CD8⁺ effector T cell responses. Specific Pattern Recognition Receptor (PRR) triggering during maturation enables DC to enhance Th1 as well as NK helper cell responses. This effect is correlated with the amount of IL-12p70 released by DC. Activated NK cells are able to amplify the proinflammatory cytokine profile of DC via the release of IFN-γ. The knowledge on how PAMP recognition can modulate the DC is of importance for the design and definition of appropriate therapeutic cancer vaccines. In this review we will discuss the potential role of specific PAMP-matured DC in optimizing therapeutic DC-based vaccines, as some of these DC are efficiently activating Th1, NK cells, and cytotoxic T cells. Moreover, to optimize these vaccines, also the inhibitory effects of tumor-derived suppressive factors, for example, on the NK-DC crosstalk, should be taken into account. Finally, the suppressive role of the tumor microenvironment in vaccination efficacy and some proposals to overcome this by using combination therapies will be described.

Dendritic cell vaccines containing lymphocytes produce improved immunogenicity in patients with cancer

BACKGROUND

Dendritic cells are currently under investigation for their ability to generate anti-cancer immune responses. No consensus has been reached as to the optimal method of dendritic cell vaccine preparation and is a barrier to success in the field.

METHODS

Over a course of three separate dendritic cell vaccine studies to treat cancer, we tested two different methods for preparing dendritic cells from peripheral blood mononuclear cells: adherence and antibody-selected CD14+ cells.

RESULTS

Surprisingly, we found that patients who received dendritic cell vaccines generated by the adherence method mounted increased T cell proliferation in response to vaccination. This difference could not be accounted for by dendritic cell vaccine dose, cell surface phenotype or dendritic cell function in vitro. One notable difference between the two vaccine preparation methods was that the dendritic cell vaccine cultures generated by the adherence method contained up to 10% lymphocytes, and these lymphocytes were proliferating and producing IFNγ in response to antigen in vitro at the time of administration.

CONCLUSIONS

Enhanced immunogenicity of adherence dendritic cell vaccinations may be due to the presence of lymphocytes during dendritic cell culture.

TRIAL REGISTRATION

Clinicaltrials.gov identifiers: NCT00289341, NCT00345293, and NCT00893945.

Therapeutic cancer vaccines and combination immunotherapies involving vaccination

Recent US Food and Drug Administration approvals of Provenge(®) (sipuleucel-T) as the first cell-based cancer therapeutic factor and ipilimumab (Yervoy(®)/anticytotoxic T-lymphocyte antigen-4) as the first "checkpoint blocker" highlight recent advances in cancer immunotherapy. Positive results of the clinical trials evaluating additional checkpoint blocking agents (blockade of programmed death [PD]-1, and its ligands, PD-1 ligand 1 and 2) and of several types of cancer vaccines suggest that cancer immunotherapy may soon enter the center stage of comprehensive cancer care, supplementing surgery, radiation, and chemotherapy. This review discusses the current status of the clinical evaluation of different classes of therapeutic cancer vaccines and possible avenues for future development, focusing on enhancing the magnitude and quality of cancer-specific immunity by either the functional reprogramming of patients' endogenous dendritic cells or the use of ex vivo-manipulated dendritic cells as autologous cellular transplants. This review further discusses the available strategies aimed at promoting the entry of vaccination-induced T-cells into tumor tissues and prolonging their local antitumor activity. Finally, the recent improvements to the above three modalities for cancer immunotherapy (inducing tumor-specific T-cells, prolonging their persistence and functionality, and enhancing tumor homing of effector T-cells) and rationale for their combined application in order to achieve clinically effective anticancer responses are addressed.