CD4+ T cells indirectly kill tumor cells via induction of cytotoxic macrophages in mouse models

CD4+ T cells in antitumor immunity

Advances in cancer immunotherapy have transformed cancer care and realized unprecedented responses in many patients. The growing arsenal of novel therapeutics - including immune checkpoint inhibition (ICI), adoptive T cell therapies (ACTs), and cancer vaccines - reflects the success of cancer immunotherapy. The therapeutic benefits of these treatment modalities are generally attributed to the enhanced quantity and quality of antitumor CD8+ T cell responses. Nevertheless, CD4+ T cells are now recognized to play key roles in both the priming and effector phases of the antitumor immune response. In addition to providing T cell help through co-stimulation and cytokine production, CD4+ T cells can also possess cytotoxicity either directly on MHC class II-expressing tumor cells or to other cells within the tumor microenvironment (TME). The presence of specific populations of CD4+ T cells, and their intrinsic plasticity, within the TME can represent an important determinant of clinical response to immune checkpoint inhibitors, vaccines, and chimeric antigen receptor (CAR) T cell therapies. Understanding how the antitumor functions of specific CD4+ T cell types are induced while limiting their protumorigenic attributes will enable more successful immunotherapies.

Entering the TiME machine: How age-related changes in the tumor immune microenvironment impact melanoma progression and therapy response

Melanoma is the deadliest form of skin cancer in the United States, with its incidence rates rising in older populations. As the immune system undergoes age-related changes, these alterations can significantly influence tumor progression and the effectiveness of cancer treatments. Recent advancements in understanding immune checkpoint molecules have paved the way for the development of innovative immunotherapies targeting solid tumors. However, the aging tumor microenvironment can play a crucial role in modulating the response to these immunotherapeutic approaches. This review seeks to examine the intricate relationship between age-related changes in the immune system and their impact on the efficacy of immunotherapies, particularly in the context of melanoma. By exploring this complex interplay, we hope to elucidate potential strategies to optimize treatment outcomes for older patients with melanoma, and draw parallels to other cancers.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

m6A- and m5C- modified lncRNAs orchestrate the prognosis in cutaneous melanoma and m6A- modified LINC00893 regulates cutaneous melanoma cell metastasis

BACKGROUND

As the most important modifications on the RNA level, N6-methyladenosine (m6A-) and 5-methylcytosine (m5C-) modification could have a direct influence on the RNAs. Long non-coding RNAs (lncRNAs) could also be modified by methylcytosine modification. Compared with mRNAs, the function of lncRNAs could be more potent to some extent in biological processes like tumorigenesis. Until now, rare reports have been done associated with cutaneous melanoma. Herein, we wonder if the m6A- and m5C- modified lncRNAs could influence the immune landscape and prognosis in melanoma, and we also want to find some lncRNAs which could directly affect the malignant behaviors of melanoma.

METHODS

Systematically, we explored the expression pattern of m6A- and m5C- modified lncRNAs in melanoma from datasets including UCSC Xena and NCBI GEO, and the prognostic lncRNAs were selected. Then, according to the expression pattern of lncRNAs, melanoma samples from these datasets were divided into several subtypes. Prognostic model, nomogram survival model, drug sensitivity, GO, and KEGG pathway analysis were performed. Furthermore, among several selected lncRNAs, we identified one lncRNA named LINC00893 and investigated its expression pattern and its biological function in melanoma cell lines.

RESULTS

We identified 27 m6A- and m5C- related lncRNAs which were significantly associated with survival, and we made a subtype analysis of melanoma samples based on these 27 lncRNAs. Among the two subtypes, we found differences of immune cells infiltration between these two subtypes. Then, LASSO algorithm was used to screen the optimized lncRNAs combination including ZNF252P-AS1, MIAT, FAM13A-AS1, LINC-PINT, LINC00893, AGAP2-AS1, OIP5-AS1, and SEMA6A-AS1. We also found that there was a significant correlation between the different risk groups predicted based on RS model and the actual prognosis. The nomogram survival model based on independent survival prognostic factors was also constructed. Besides, sensitivity to chemotherapeutic agents, GO and KEGG analysis were performed. In different risk groups, a total of 14 drug molecules with different distributions were obtained, which included AZD6482, AZD7762, AZD8055, camptothecin, dasatinib, erlotinib, gefitinib, gemcitabine, GSK269962A, nilotinib, rapamycin, and sorafenib. A total of 55 significantly related biological processes and 17 KEGG signaling pathways were screened. At last, we noticed that LINC00893 had a relatively lower expression in melanoma tissue and cell lines compared with adjacent tissues and epidermal melanocyte, and down-regulation of LINC00893 could promote the malignant behavior of melanoma cells in A875 and MV3. In these two melanoma cell lines, down-regulation of m6A-related molecules like YTHDF3 and METTL3 could promote the expression of LINC00893.

CONCLUSION

We made an analysis of m6A- and m5C- related lncRNAs in melanoma samples and a prediction of these lncRNAs' role in prognosis, tumor microenvironment, immune infiltration, and clinicopathological features. We also found that LINC00893, which is potentially regulated by m6A modification, could serve as a tumor-suppressor in melanoma and play an inhibitory role in melanoma metastasis.

Hand in hand to successful immunotherapy: CD8+ T cells and M1-like macrophages swap the baton

Cancer immunotherapy is a pillar of clinical oncology but only achieves long-term remissions in a minority of cases. In this issue, van Elsas et al. show that effective immunotherapy requires a series of processes orchestrated by CD8+ T cells that result in the recruitment and local activation of M1-like macrophages.

Immunotherapy-activated T cells recruit and skew late-stage activated M1-like macrophages that are critical for therapeutic efficacy

Total tumor clearance through immunotherapy is associated with a fully coordinated innate and adaptive immune response, but knowledge on the exact contribution of each immune cell subset is limited. We show that therapy-induced intratumoral CD8+ T cells recruited and skewed late-stage activated M1-like macrophages, which were critical for effective tumor control in two different murine models of cancer immunotherapy. The activated CD8+ T cells summon these macrophages into the tumor and their close vicinity via CCR5 signaling. Exposure of non-polarized macrophages to activated T cell supernatant and tumor lysate recapitulates the late-stage activated and tumoricidal phenotype in vitro. The transcriptomic signature of these macrophages is also detected in a similar macrophage population present in human tumors and coincides with clinical response to immune checkpoint inhibitors. The requirement of a functional co-operation between CD8+ T cells and effector macrophages for effective immunotherapy gives warning to combinations with broad macrophage-targeting strategies.

Long-lasting mRNA-encoded interleukin-2 restores CD8+ T cell neoantigen immunity in MHC class I-deficient cancers

Major histocompatibility complex (MHC) class I antigen presentation deficiency is a common cancer immune escape mechanism, but the mechanistic implications and potential strategies to address this challenge remain poorly understood. Studying β2-microglobulin (B2M) deficient mouse tumor models, we find that MHC class I loss leads to a substantial immune desertification of the tumor microenvironment (TME) and broad resistance to immune-, chemo-, and radiotherapy. We show that treatment with long-lasting mRNA-encoded interleukin-2 (IL-2) restores an immune cell infiltrated, IFNγ-promoted, highly proinflammatory TME signature, and when combined with a tumor-targeting monoclonal antibody (mAB), can overcome therapeutic resistance. Unexpectedly, the effectiveness of this treatment is driven by IFNγ-releasing CD8+ T cells that recognize neoantigens cross-presented by TME-resident activated macrophages. These macrophages acquire augmented antigen presentation proficiency and other M1-phenotype-associated features under IL-2 treatment. Our findings highlight the importance of restoring neoantigen-specific immune responses in the treatment of cancers with MHC class I deficiencies.

CD4+ T cell immunity against cutaneous melanoma encompasses multifaceted MHC II-dependent responses

Whereas CD4+ T cells conventionally mediate antitumor immunity by providing help to CD8+ T cells, recent clinical studies have implied an important role for cytotoxic CD4+ T cells in cancer immunity. Using an orthotopic melanoma model, we provide a detailed account of antitumoral CD4+ T cell responses and their regulation by major histocompatibility complex class II (MHC II) in the skin. Intravital imaging revealed prominent interactions of CD4+ T cells with tumor debris-laden MHC II+ host antigen-presenting cells that accumulated around tumor cell nests, although direct recognition of MHC II+ melanoma cells alone could also promote CD4+ T cell control. CD4+ T cells stably suppressed or eradicated tumors even in the absence of other lymphocytes by using tumor necrosis factor-α and Fas ligand (FasL) but not perforin-mediated cytotoxicity. Interferon-γ was critical for protection, acting both directly on melanoma cells and via induction of nitric oxide synthase in myeloid cells. Our results illustrate multifaceted and context-specific aspects of MHC II-dependent CD4+ T cell immunity against cutaneous melanoma, emphasizing modulation of this axis as a potential avenue for immunotherapies.

The role of CD4+ T cells in tumor and chronic viral immune responses

Immunotherapies are mainly aimed to promote a CD8+ T cell response rather than a CD4+ T cell response as cytotoxic T lymphocytes (CTLs) can directly kill target cells. Recently, CD4+ T cells have received more attention due to their diverse roles in tumors and chronic viral infections. In antitumor and antichronic viral responses, CD4+ T cells relay help signals through dendritic cells to indirectly regulate CD8+ T cell response, interact with B cells or macrophages to indirectly modulate humoral immunity or macrophage polarization, and inhibit tumor blood vessel formation. Additionally, CD4+ T cells can also exhibit direct cytotoxicity toward target cells. However, regulatory T cells exhibit immunosuppression and CD4+ T cells become exhausted, which promote tumor progression and chronic viral persistence. Finally, we also outline immunotherapies based on CD4+ T cells, including adoptive cell transfer, vaccines, and immune checkpoint blockade. Overall, this review summarizes diverse roles of CD4+ T cells in the antitumor or protumor and chronic viral responses, and also highlights the immunotherapies based on CD4+ T cells, giving a better understanding of their roles in tumors and chronic viral infections.

Advances in vaccine development for cancer prevention and treatment in Lynch Syndrome

Lynch Syndrome (LS) is one of the most common hereditary cancer syndromes, and is caused by mutations in one of the four DNA mismatch repair (MMR) genes, namely MLH1, MSH2, MSH6 and PMS2. Tumors developed by LS carriers display high levels of microsatellite instability, which leads to the accumulation of large numbers of mutations, among which frameshift insertion/deletions (indels) within microsatellite (MS) loci are the most common. As a result, MMR-deficient (MMRd) cells generate increased rates of tumor-specific neoantigens (neoAgs) that can be recognized by the immune system to activate cancer cell killing. In this context, LS is an ideal disease to leverage immune-interception strategies. Therefore, the identification of these neoAgs is an ongoing effort for the development of LS cancer preventive vaccines. In this review, we summarize the computational methods used for in silico neoAg prediction, including their challenges, and the experimental techniques used for in vitro validation of their immunogenicity. In addition, we outline results from past and on-going vaccine clinical trials and highlight avenues for improvement and future directions.

Lung tumor-infiltrating Treg have divergent transcriptional profiles and function linked to checkpoint blockade response

Regulatory T cells (Treg) are conventionally viewed as suppressors of endogenous and therapy-induced antitumor immunity; however, their role in modulating responses to immune checkpoint blockade (ICB) is unclear. In this study, we integrated single-cell RNA-seq/T cell receptor sequencing (TCRseq) of >73,000 tumor-infiltrating Treg (TIL-Treg) from anti-PD-1-treated and treatment-naive non-small cell lung cancers (NSCLC) with single-cell analysis of tumor-associated antigen (TAA)-specific Treg derived from a murine tumor model. We identified 10 subsets of human TIL-Treg, most of which have high concordance with murine TIL-Treg subsets. Only one subset selectively expresses high levels of TNFRSF4 (OX40) and TNFRSF18 (GITR), whose engangement by cognate ligand mediated proliferative programs and NF-κB activation, as well as multiple genes involved in Treg suppression, including LAG3. Functionally, the OX40hiGITRhi subset is the most highly suppressive ex vivo, and its higher representation among total TIL-Treg correlated with resistance to PD-1 blockade. Unexpectedly, in the murine tumor model, we found that virtually all TIL-Treg-expressing T cell receptors that are specific for TAA fully develop a distinct TH1-like signature over a 2-week period after entry into the tumor, down-regulating FoxP3 and up-regulating expression of TBX21 (Tbet), IFNG, and certain proinflammatory granzymes. Transfer learning of a gene score from the murine TAA-specific TH1-like Treg subset to the human single-cell dataset revealed a highly analogous subcluster that was enriched in anti-PD-1-responding tumors. These findings demonstrate that TIL-Treg partition into multiple distinct transcriptionally defined subsets with potentially opposing effects on ICB-induced antitumor immunity and suggest that TAA-specific TIL-Treg may positively contribute to antitumor responses.

Optimized dithranol-imiquimod-based transcutaneous immunization enables tumor rejection

Introduction

Transcutaneous immunization (TCI) is a non-invasive vaccination method promoting strong cellular immune responses, crucial for the immunological rejection of cancer. Previously, we reported on the combined application of the TLR7 agonist imiquimod (IMQ) together with the anti-psoriatic drug dithranol as novel TCI platform DIVA (dithranol/IMQ based vaccination). In extension of this work, we further optimized DIVA in terms of drug dose, application pattern and established a new IMQ formulation.

Methods

C57BL/6 mice were treated on the ear skin with dithranol and IMQ-containing ointments together with ovalbumin-derived peptides. T cell responses were determined by flow cytometry and IFN-ɤ ELISpot assay, local skin inflammation was characterized by ear swelling.

Results

Applying the adjuvants on separate skin sites, a reduced number of specific CD8+ T cells with effector function was detectable, indicating that the local concurrence of adjuvants and peptide antigens is required for optimal vaccination. Likewise, changing the order of dithranol and IMQ resulted in an increased skin inflammatory reaction, but lower frequencies of antigen-specific CD8+ T cells indicating that dithranol is essential for superior T cell priming upon DIVA. Dispersing nanocrystalline IMQ in a spreadable formulation (IMI-Sol+) facilitated storage and application rendering comparable immune responses. DIVA applied one or two weeks after the first immunization resulted in a massive increase in antigen-specific T cells and up to a ten-fold increased memory response. Finally, in a prophylactic tumor setting, double but no single DIVA treatment enabled complete control of tumor growth, resulting in full tumor protection.

Discussion

Taken together, the described optimized transcutaneous vaccination method leads to the generation of a strong cellular immune response enabling the effective control of tumor growth and has the potential for clinical development as a novel non-invasive vaccination method for peptide-based cancer vaccines in humans.

KCND2: A prognostic biomarker and regulator of immune function in gastric cancer

BACKGROUND

Gastric cancer is a highly heterogeneous disease, which makes it challenging to develop effective targeted therapies. Although the potassium voltage-gated channel subfamily D (KCND) channels, particularly KCND2 (also known as Kv4.2), have found evidence of involvement in the occurrence and development of various cancers, there are still some limitations in our understanding of KCND2's roles in gastric cancer.

METHODS

We analyzed the correlation between KCND2 expression and clinical features as well as immune infiltration using the Cancer Genome Atlas (TCGA) database. Functional assays of KCND2 were conducted using Cell counting Kit-8 (CCK8), clone formation assay and cell cycle analysis. Additionally, immunofluorescence, flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR) techniques were used to investigate tumor proliferation and immune cell infiltration at different levels of KCND2 expression in vivo.

RESULTS

KCND2 was markedly elevated in gastric cancer and its expression appeared to link to different grades, T stages, and N stages. In addition, KCND2 was an independent predictor of prognosis, and its elevated levels in TCGA database revealed a more unfavorable prognosis for patients with gastric cancer. KCND2 strengthened the viability at the cellular level by boosting the proliferation of gastric cancer cells and reducing their death rate. Additionally, it also highlights that KCND2 the abilities of proliferating of gastric cancer cells by stimulating NF-κB both in cell and animal levels. In addition, the findings provided proof that in animal levels, KCND2 might regulate the immune system by associating with promoting M2 macrophages, which are known to play critical roles in cancer progression. Mechanistically, KCND2 was found to lead to the infiltration of M2 macrophages through activation of NF-κB, ultimately promoting the advancement of gastric cancer.

CONCLUSION

Overall, these findings suggest that KCND2 is likely to be available as an underlying therapeutic target for gastric cancer.

Tumor-intrinsic sensitivity to the pro-apoptotic effects of IFN-γ is a major determinant of CD4+ CAR T-cell antitumor activity

CD4+ T cells and CD4+ chimeric antigen receptor (CAR) T cells display highly variable antitumor activity in preclinical models and in patients; however, the mechanisms dictating how and when CD4+ T cells promote tumor regression are incompletely understood. With the help of functional intravital imaging, we report that interferon (IFN)-γ production but not perforin-mediated cytotoxicity was the dominant mechanism for tumor elimination by anti-CD19 CD4+ CAR T cells. Mechanistically, mouse or human CD4+ CAR T-cell-derived IFN-γ diffused extensively to act on tumor cells at distance selectively killing tumors sensitive to cytokine-induced apoptosis, including antigen-negative variants. In anti-CD19 CAR T-cell-treated patients exhibiting elevated CAR CD4:CD8 ratios, strong induction of serum IFN-γ was associated with increased survival. We propose that the sensitivity of tumor cells to the pro-apoptotic activity of IFN-γ is a major determinant of CD4+ CAR T-cell efficacy and may be considered to guide the use of CD4+ T cells during immunotherapy.

Role of T cells in cancer immunotherapy: Opportunities and challenges

Immunotherapies boosting the immune system's ability to target cancer cells are promising for the treatment of various tumor types, yet clinical responses differ among patients and cancers. Recently, there has been increasing interest in novel cancer immunotherapy practices aimed at triggering T cell-mediated anti-tumor responses. Antigen-directed cytotoxicity mediated by T lymphocytes has become a central focal point in the battle against cancer utilizing the immune system. The molecular and cellular mechanisms involved in the actions of T lymphocytes have directed new therapeutic approaches in cancer immunotherapy, including checkpoint blockade, adoptive and chimeric antigen receptor (CAR) T cell therapy, and cancer vaccinology. This review addresses all the strategies targeting tumor pathogenesis, including metabolic pathways, to evaluate the clinical significance of current and future immunotherapies for patients with cancer, which are further engaged in T cell activation, differentiation, and response against tumors.

CD4+ T cells in cancer

Cancer immunology and immunotherapy are driving forces of research and development in oncology, mostly focusing on CD8⁺ T cells and the tumor microenvironment. Recent progress highlights the importance of CD4⁺ T cells, corresponding to the long-known fact that CD4⁺ T cells are central players and coordinators of innate and antigen-specific immune responses. Moreover, they have now been recognized as anti-tumor effector cells in their own right. Here we review the current status of CD4⁺ T cells in cancer, which hold great promise for improving knowledge and therapies in cancer.

NUDT1 Could Be a Prognostic Biomarker and Correlated with Immune Infiltration in Clear Cell Renal Cell Carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a malignant tumor with high morbidity and mortality. As a member of the Nudix hydrolase superfamily, Nudix (nucleoside diphosphate-linked moiety X)-type motif 1 (NUDT1) is closely related to the occurrence and development of cancer. Our study aims to explore the role of NUDT1 in ccRCC and its relationship with immune infiltration.

Methods

The NUDT1 expression matrix and corresponding clinical information were obtained from The Cancer Genome Atlas (TCGA) database. The expression difference of NUDT1 in ccRCC and its relationship with the clinical characteristics were investigated using R software. Kaplan-Meier (K-M) analysis, univariate Cox regression, multivariate Cox regression, receiver operating characteristic (ROC) curve, and nomogram were utilized to evaluate the survival and prognosis of patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to explore the function of differential genes in low- or high-expression group of NUDT1. TCGA dataset and Tumor IMmune Estimation Resource (TIMER) database were utilized to explore the relationship between NUDT1 and immune infiltration. Finally, TCGA dataset was utilized for gene set enrichment analysis (GSEA).

Results

NUDT1 was not only overexpressed in ccRCC but also significantly correlated with clinicopathological features (P < 0.05). K-M survival analysis showed that upregulated NUDT1 was closely related to the decrease of overall survival (OS) and progression-free survival (PFS) in ccRCC patients. Multivariate Cox regression revealed that NUDT1 was a independent prognostic indicator (HR = 1.437, 95% CI: 1.065-1.939, P=0.018). The ROC curve showed that NUDT1 had a certain accuracy in predicting the outcome of ccRCC patiens. Furthermore, a total of 150 coexpressed genes and 1,886 differentially expressed genes (DEGs) were identified. GO/KEGG and GSEA results suggested that NUDT1 and its DEGs were involved in the immune-related pathways. NUDT1 expression was positively correlated with infiltrating levels of regulatory T cells (Tregs), CD8⁺ T cells, follicular helper T cells, and M0 macrophages. In addition, NUDT1 was positively related to immune checkpoints, such as PD-1, LAG3, CTLA4, and CD70, in ccRCC.

Conclusion

NUDT1 plays a key role in the prognosis and immune cell infiltration of ccRCC patients, indicating its potential use as a prognostic biomarker and therapeutic target.

Combining a nanoparticle-mediated immunoradiotherapy with dual blockade of LAG3 and TIGIT improves the treatment efficacy in anti-PD1 resistant lung cancer

BACKGROUND

While improvements in immunoradiotherapy have significantly improved outcomes for cancer patients, this treatment approach has nevertheless proven ineffective at controlling the majority of malignancies. One of the mechanisms of resistance to immunoradiotherapy is that immune cells may be suppressed via the myriad of different immune checkpoint receptors. Therefore, simultaneous blockade of multiple immune checkpoint receptors may enhance the treatment efficacy of immunoradiotherapy.

METHODS

We combined NBTXR3-enhanced localized radiation with the simultaneous blockade of three different checkpoint receptors: PD1, LAG3, and TIGIT, and tested the treatment efficacy in an anti-PD1-resistant lung cancer model in mice. 129 Sv/Ev mice were inoculated with fifty thousand αPD1-resistant 344SQR cells in the right leg on day 0 to establish primary tumors and with the same number of cells in the left leg on day 4 to establish the secondary tumors. NBTXR3 was intratumorally injected into the primary tumors on day 7, which were irradiated with 12 Gy on days 8, 9, and 10. Anti-PD1 (200 µg), αLAG3 (200 µg), and αTIGIT (200 µg) were given to mice by intraperitoneal injections on days 5, 8, 11, 14, 21, 28, 35, and 42.

RESULTS

This nanoparticle-mediated combination therapy is effective at controlling the growth of irradiated and distant unirradiated tumors, enhancing animal survival, and is the only one that led to the destruction of both tumors in approximately 30% of the treated mice. Corresponding with this improved response is robust activation of the immune response, as manifested by increased numbers of immune cells along with a transcriptional signature of both innate and adaptive immunity within the tumor. Furthermore, mice treated with this combinatorial therapy display immunological memory response when rechallenged by the same cancer cells, preventing tumor engraftment.

CONCLUSION

Our results strongly attest to the efficacy and validity of combining nanoparticle-enhanced radiotherapy and simultaneous blockade of multiple immune checkpoint receptors and provide a pre-clinical rationale for investigating its translation into human patients.

Seaweeds in the Oncology Arena: Anti-Cancer Potential of Fucoidan as a Drug—A Review

Marine natural products are a discerning arena to search for the future generation of medications to treat a spectrum of ailments. Meanwhile, cancer is becoming more ubiquitous over the world, and the likelihood of dying from it is rising. Surgery, radiation, and chemotherapy are the mainstays of cancer treatment worldwide, but their extensive side effects limit their curative effect. The quest for low-toxicity marine drugs to prevent and treat cancer is one of the current research priorities of researchers. Fucoidan, an algal sulfated polysaccharide, is a potent therapeutic lead candidate against cancer, signifying that far more research is needed. Fucoidan is a versatile, nontoxic marine-origin heteropolysaccharide that has received much attention due to its beneficial biological properties and safety. Fucoidan has been demonstrated to exhibit a variety of conventional bioactivities, such as antiviral, antioxidant, and immune-modulatory characteristics, and anticancer activity against a wide range of malignancies has also recently been discovered. Fucoidan inhibits tumorigenesis by prompting cell cycle arrest and apoptosis, blocking metastasis and angiogenesis, and modulating physiological signaling molecules. This review compiles the molecular and cellular aspects, immunomodulatory and anticancer actions of fucoidan as a natural marine anticancer agent. Specific fucoidan and membranaceous polysaccharides from Ecklonia cava, Laminaria japonica, Fucus vesiculosus, Astragalus, Ascophyllum nodosum, Codium fragile serving as potential anticancer marine drugs are discussed in this review.

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.

Dynamic CD8+ T Cell Cooperation with Macrophages and Monocytes for Successful Cancer Immunotherapy

Simple Summary

Innate and adaptive immunity mutually regulate one another in a dynamic fashion during immune responses. In infectious contexts, positive interactions between macrophages, monocytes and T cells are well recognized, but this is not the case in the field of cancer, where the growth of tumors disturbs the immune response. However, recent advances revealed that successful immunotherapy profoundly remodels the tumor microenvironment, promoting the activation of both T cells and myeloid cells. This review highlights the studies that hint at positive CD8⁺ T cell cooperation with monocytes and macrophages in this context, and discusses the potential mechanisms behind this.

Abstract

The essential roles endorsed by macrophages and monocytes are well established in response to infections, where they contribute to launching the differentiation of specific T-lymphocytes for long-term protection. This knowledge is the result of dynamic studies that can inspire the cancer field, particularly now that cancer immunotherapies elicit some tumor regression. Indeed, immune responses to cancer have mainly been studied after tumors have escaped immune attacks. In particular, the suppressive functions of macrophages were revealed in this context, introducing an obvious bias across the literature. In this review, we will focus on the ways inwhich monocytes and macrophages cooperate with T-lymphocytes, leading to successful immune responses. We will bring together the preclinical studies that have revealed the existence of such positive cooperation in the cancer field, and we will place particular emphasis on proposing the underlying mechanisms. Finally, we will give some perspectives to decipher the functional roles of such T-cell and myeloid cell interactions in the frame of human cancer immunotherapy.

The Era of Cytotoxic CD4 T Cells

In 1986, Mosmann and Coffman identified 2 functionally distinct subsets of activated CD4 T cells, Th1 and Th2 cells, being key in distinct T cell mediated responses. Over the past three decades, our understanding of CD4 T cell differentiation has expanded and the initial paradigm of a dichotomic CD4 T cell family has been revisited to accommodate a constantly growing number of functionally distinct CD4 T helper and regulatory subpopulations. Of note, CD4 T cells with cytotoxic functions have also been described, initially in viral infections, autoimmune disorders and more recently also in cancer settings. Here, we provide an historical overview on the discovery and characterization of cytotoxic CD4 T cells, followed by a description of their mechanisms of cytotoxicity. We emphasize the relevance of these cells in disease conditions, particularly in cancer, and we provide insights on how to exploit these cells in immunotherapy.

Role of macrophages in tumor progression and therapy (Review)

The number and phenotype of macrophages are closely related to tumor growth and prognosis. Macrophages are recruited to (and polarized at) the tumor site thereby promoting tumor growth, stimulating tumor angiogenesis, facilitating tumor cell migration, and creating a favorable environment for subsequent colonization by (and survival of) tumor cells. These phenomena contribute to the formation of an immunosuppressive tumor microenvironment (TME) and therefore speed up tumor cell proliferation and metastasis and reduce the efficacy of antitumor factors and therapies. The ability of macrophages to remodel the TME through interactions with other cells and corresponding changes in their number, activity, and phenotype during conventional therapies, as well as the association between these changes and drug resistance, make tumor-associated macrophages a new target for antitumor therapies. In this review, advantages and limitations of the existing antitumor strategies targeting macrophages in Traditional Chinese and Western medicine were analyzed, starting with the effect of macrophages on tumors and their interactions with other cells and then the role of macrophages in conventional treatments was explored. Possible directions of future developments in this field from an all-around multitarget standpoint were also examined.

PAD-2-mediated citrullination of nucleophosmin provides an effective target for tumor immunotherapy

BACKGROUND

The enzymatic conversion of arginine to citrulline is involved in gene and protein regulation and in alerting the immune system to stressed cells, including tumor cells. Nucleophosmin (NPM) is a nuclear protein that plays key roles in cellular metabolism including ribosome biogenesis, mRNA processing and chromatin remodeling and is regulated by citrullination. In this study, we explored if the same citrullinated arginines within NPM are involved in gene regulation and immune activation.

METHODS

HLA-DP4 and HLA-DR4 transgenic mice were immunized with 22 citrullinated NPM overlapping peptides and immune responses to the peptides were assessed by ex vivo ELISpot assays. Antitumor immunity of NPM targeted vaccination was assessed by challenging transgenic mice with B16F1 HHDII/iDP4, B16F1 HHDII/PAD2KOcDP4, B16F1 HHDII and Lewis lung carcinoma cells/cDP4 cells subcutaneously. Peripheral blood mononuclear cells isolated from healthy donors were stimulated with NPM266-285cit peptides with/without CD45RO+memory cell depletion to assess if the responses in human were naïve or memory.

RESULTS

In contrast to NPM regulation, which is mediated by peptidylarginine deiminase (PAD4) citrullination of arginine at position 197, only citrullinated NPM266-285 peptide induced a citrulline-specific CD4 T cell response in transgenic mice models expressing human HLA-DP4 or HLA-DR4. Vaccinations with the NPM266-285cit peptide stimulated antitumor responses that resulted in dramatic tumor therapy, greatly improved survival, and protected against rechallenge without further vaccination. The antitumor response was lost if MHCII expression on the tumor cells was knocked out demonstrating direct presentation of the NPM266-285cit epitope in tumors. This antitumor response was lost in B16 tumors lacking PAD2 enzyme indicating NPM266cit is citrullinated by PAD2 in this model. Assessment of the T cell repertoire in healthy individuals and patients with lung cancer also showed CD4 T cells that respond to NPM266-285cit. The proliferative CD4 responses displayed a Th1 profile as they were accompanied with increased IFNγ and granzyme B expression. Depletion of CD45RO+ memory cells prior to stimulation suggested that responses originated from a naïve population in healthy donors.

CONCLUSION

This study indicates PAD2 can citrullinate the nuclear antigen NPM at position 277 which can be targeted by CD4 T cells for antitumor therapy. This is distinct from PAD4 citrullination of arginine 197 within NPM which results in its transport from the nucleoli to the nucleoplasm.

Roles of CD4+ T cells as mediators of antitumor immunity

It has been well established that CD8+ T cells serve as effector cells of the adaptive immune response against tumors, whereas CD4+ T cells either help or suppress the generation of CD8+ cytotoxic T cells. However, in several experimental models as well as in cancer patients, it has been shown that CD4+ T cells can also mediate antitumor immunity either directly by killing tumor cells or indirectly by activating innate immune cells or by reducing tumor angiogenesis. In this review, we discuss the growing evidence of this underappreciated role of CD4+ T cells as mediators of antitumor immunity.

Mannan-BAM, TLR ligands, and anti-CD40 immunotherapy in established murine pancreatic adenocarcinoma: understanding therapeutic potentials and limitations

Pancreatic adenocarcinoma is one of the leading causes of cancer-related deaths, and its therapy remains a challenge. Our proposed therapeutic approach is based on the intratumoral injections of mannan-BAM, toll-like receptor ligands, and anti-CD40 antibody (thus termed MBTA therapy), and has shown promising results in the elimination of subcutaneous murine melanoma, pheochromocytoma, colon carcinoma, and smaller pancreatic adenocarcinoma (Panc02). Here, we tested the short- and long-term effects of MBTA therapy in established subcutaneous Panc02 tumors two times larger than in previous study and bilateral Panc02 models as well as the roles of CD4+ and CD8+ T lymphocytes in this therapy. The MBTA therapy resulted in eradication of 67% of Panc02 tumors with the development of long-term memory as evidenced by the rejection of Panc02 cells after subcutaneous and intracranial transplantations. The initial Panc02 tumor elimination is not dependent on the presence of CD4+ T lymphocytes, although these cells seem to be important in long-term survival and resistance against tumor retransplantation. The resistance was revealed to be antigen-specific due to its inability to reject B16-F10 melanoma cells. In the bilateral Panc02 model, MBTA therapy manifested a lower therapeutic response. Despite numerous combinations of MBTA therapy with other therapeutic approaches, our results show that only simultaneous application of MBTA therapy into both tumors has potential for the treatment of the bilateral Panc02 model.

Recruitment of M1 Macrophages May Not Be Critical for Protection against Colitis-Associated Tumorigenesis

A close connection between inflammation and the risk of developing colon cancer has been suggested in the last few years. It has been estimated that patients diagnosed with some types of inflammatory bowel disease, such as ulcerative colitis or Crohn's disease, have up to a 30% increased risk of developing colon cancer. However, there is also evidence showing that the activation of anti-inflammatory pathways, such as the IL-4 receptor-mediated pathway, may favor the development of colon tumors. Using an experimental model of colitis-associated colon cancer (CAC), we found that the decrease in tumor development in global IL4Rα knockout mice (IL4RαKO) was apparently associated with an inflammatory response mediated by the infiltration of M1 macrophages (F480+TLR2+STAT1+) and iNOS expression in colon tissue. However, when we developed mice with a specific deletion of IL4Rα in macrophages (LysMcreIL4Rα-/lox mice) and subjected them to CAC, it was found that despite presenting a large infiltration of M1 macrophages into the colon, these mice were as susceptible to colon-tumorigenesis as WT mice. These data suggest that in the tumor microenvironment the absence of IL4Rα expression on macrophages, as well as the recruitment of M1 macrophages, may not be directly associated with resistance to developing colon tumors. Therefore, it is possible that IL4Rα expression in other cell types, such as colonic epithelial cells, could have an important role in promoting the development of colitis-associated colon tumorigenesis.

The role of CD4 T cells in rejection of solid tumors

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Versatility of CD4 T cells enables different attack modes towards cancer cells.

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Cooperation of CD4 and CD8 T cells renders anti-tumor responses most efficient.

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Integrating CD4 T cells in cancer therapy will improve clinical outcome.

The focus in cancer immunotherapy has mainly been on CD8 T cells, as they can directly recognize cancer cells. CD4 T cells have largely been neglected, because most cancers lack MHC II expression and cannot directly be recognized by CD4 T cells. Yet, tumor antigens can be captured and cross-presented by MHC II-expressing tumor stromal cells. Recent data suggest that CD4 T cells act as a swiss army knife against tumors. They can kill cancer cells, if they express MHC II, induce tumoricidal macrophages, induces cellular senescence of cancer cells, destroy the tumor vasculature through cytokine release and help CD8 T cells in the effector phase. We foresee a great future for CD4 T cells in the clinic, grafted with tumor antigen specificity by T cell receptor gene transfer, either alone or in combination with engineered CD8 T cells.

Identification and Experimental Validation of Immune-Associate lncRNAs for Predicting Prognosis in Cervical Cancer

Purpose

Cervical cancer (CC) is a major risk for health of modern women. Immune-related long non-coding RNAs (lncRNAs) can also serve as prognostic markers of overall survival (OS) in patients with CC. This study aimed to identify an immune-related lncRNA signature for the prospective assessment of prognosis in CC patients.

Methods

We first calculated immune scores of CC patients in the Cancer Genome Atlas (TCGA) database. Univariate Cox, Lasso Cox and multivariate Cox regression analyses were perfumed to establish an immune-relative lncRNA signature. In addition, we processed pathway enrichment analysis and immune infiltration analysis between patients with higher or lower risk. Finally, T-cell Chemotaxis assays were processed to verify the function of 2 key lncRNAs.

Results

Our results suggested that patients with higher immune scores had longer survival time and some lncRNAs expressed differentially between two groups. Eight lncRNAs (LINC02802, LINC01877, RBAKDN, LINC02480, WWC2-AS2, LINC01281, ZBTB20-AS1, IFNG-AS1) were identified as prognostic signatures for CC. The immune-related lncRNA signature was correlated with disease progression and worse prognosis. Immune infiltration analysis indicated that the expression of 8-lncRNA signatures were corrected with infiltration level of immune cell subtypes. In addition, T-cell Chemotaxis assay validated that 2 key lncRNAs (ZBTB20-AS1 and LINC01281) could significantly promote the migration ability of T cells to CC cells.

Conclusion

Our finding demonstrated the value of lncRNAs in evaluating the immune infiltrate of the tumor. The 8-lncRNA signature could predict the prognosis of CC and contribute to decisions regarding the immunotherapeutic strategy.

Identification of Immune Cell Infiltration in Murine Pheochromocytoma during Combined Mannan-BAM, TLR Ligand, and Anti-CD40 Antibody-Based Immunotherapy

Immunotherapy has become an essential component in cancer treatment. However, the majority of solid metastatic cancers, such as pheochromocytoma, are resistant to this approach. Therefore, understanding immune cell composition in primary and distant metastatic tumors is important for therapeutic intervention and diagnostics. Combined mannan-BAM, TLR ligand, and anti-CD40 antibody-based intratumoral immunotherapy (MBTA therapy) previously resulted in the complete eradication of murine subcutaneous pheochromocytoma and demonstrated a systemic antitumor immune response in a metastatic model. Here, we further evaluated this systemic effect using a bilateral pheochromocytoma model, performing MBTA therapy through injection into the primary tumor and using distant (non-injected) tumors to monitor size changes and detailed immune cell infiltration. MBTA therapy suppressed the growth of not only injected but also distal tumors and prolonged MBTA-treated mice survival. Our flow cytometry analysis showed that MBTA therapy led to increased recruitment of innate and adaptive immune cells in both tumors and the spleen. Moreover, adoptive CD4⁺ T cell transfer from successfully MBTA-treated mice (i.e., subcutaneous pheochromocytoma) demonstrates the importance of these cells in long-term immunological memory. In summary, this study unravels further details on the systemic effect of MBTA therapy and its use for tumor and metastasis reduction or even elimination.

In silico analysis identifies neuropilin-1 as a potential therapeutic target for SARS-Cov-2 infected lung cancer patients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), and is highly contagious and pathogenic. TMPRSS2 and Neuropilin-1, the key components that facilitate SARS-CoV-2 infection, are potential targets for treatment of COVID-19. Here we performed a comprehensive analysis on NRP1 and TMPRSS2 in lung to provide information for treating comorbidity of COVID-19 with lung cancer. NRP1 is widely expressed across all the human tissues while TMPRSS2 is expressed in a restricted pattern. High level of NRP1 associates with worse prognosis in multiple cancers, while high level of TMPRSS2 is associated with better survival of Lung Adenocarcinoma (LUAD). Moreover, NRP1 positively correlates with the oncogenic Cancer Associated Fibroblast (CAF), macrophage and endothelial cells infiltration, negatively correlates with infiltration of CD8⁺ T cell, the tumor killer cell in Lung Squamous cell carcinoma (LUSC). TMPRSS2 shows negative correlation with the oncogenic events in LUAD. RNA-seq data show that NRP1 level is slightly decreased in peripheral blood of ICU admitted COVID-19 patients, unaltered in lung, while TMPRSS2 level is significantly decreased in lung of COVID-19 patients. Our analysis suggests NRP1 as a potential therapeutic target, while sets an alert on targeting TMPRSS2 for treating comorbidity of COVID-19 and lung cancers.

MHC Class I Deficiency in Solid Tumors and Therapeutic Strategies to Overcome It

It is now well accepted that the immune system can control cancer growth. However, tumors escape immune-mediated control through multiple mechanisms and the downregulation or loss of major histocompatibility class (MHC)-I molecules is a common immune escape mechanism in many cancers. MHC-I molecules present antigenic peptides to cytotoxic T cells, and MHC-I loss can render tumor cells invisible to the immune system. In this review, we examine the dysregulation of MHC-I expression in cancer, explore the nature of MHC-I-bound antigenic peptides recognized by immune cells, and discuss therapeutic strategies that can be used to overcome MHC-I deficiency in solid tumors, with a focus on the role of natural killer (NK) cells and CD4 T cells.

Laboratory Mice - A Driving Force in Immunopathology and Immunotherapy Studies of Human Multiple Myeloma

Mouse models of human cancer provide an important research tool for elucidating the natural history of neoplastic growth and developing new treatment and prevention approaches. This is particularly true for multiple myeloma (MM), a common and largely incurable neoplasm of post-germinal center, immunoglobulin-producing B lymphocytes, called plasma cells, that reside in the hematopoietic bone marrow (BM) and cause osteolytic lesions and kidney failure among other forms of end-organ damage. The most widely used mouse models used to aid drug and immunotherapy development rely on in vivo propagation of human myeloma cells in immunodeficient hosts (xenografting) or myeloma-like mouse plasma cells in immunocompetent hosts (autografting). Both strategies have made and continue to make valuable contributions to preclinical myeloma, including immune research, yet are ill-suited for studies on tumor development (oncogenesis). Genetically engineered mouse models (GEMMs), such as the widely known Vκ*MYC, may overcome this shortcoming because plasma cell tumors (PCTs) develop de novo (spontaneously) in a highly predictable fashion and accurately recapitulate many hallmarks of human myeloma. Moreover, PCTs arise in an intact organism able to mount a complete innate and adaptive immune response and tumor development reproduces the natural course of human myelomagenesis, beginning with monoclonal gammopathy of undetermined significance (MGUS), progressing to smoldering myeloma (SMM), and eventually transitioning to frank neoplasia. Here we review the utility of transplantation-based and transgenic mouse models of human MM for research on immunopathology and -therapy of plasma cell malignancies, discuss strengths and weaknesses of different experimental approaches, and outline opportunities for closing knowledge gaps, improving the outcome of patients with myeloma, and working towards a cure.

Therapeutic cancer vaccines

Therapeutic cancer vaccines have undergone a resurgence in the past decade. A better understanding of the breadth of tumour-associated antigens, the native immune response and development of novel technologies for antigen delivery has facilitated improved vaccine design. The goal of therapeutic cancer vaccines is to induce tumour regression, eradicate minimal residual disease, establish lasting antitumour memory and avoid non-specific or adverse reactions. However, tumour-induced immunosuppression and immunoresistance pose significant challenges to achieving this goal. In this Review, we deliberate on how to improve and expand the antigen repertoire for vaccines, consider developments in vaccine platforms and explore antigen-agnostic in situ vaccines. Furthermore, we summarize the reasons for failure of cancer vaccines in the past and provide an overview of various mechanisms of resistance posed by the tumour. Finally, we propose strategies for combining suitable vaccine platforms with novel immunomodulatory approaches and standard-of-care treatments for overcoming tumour resistance and enhancing clinical efficacy.

CD4+ T-cell killing of multiple myeloma cells is mediated by resident bone marrow macrophages

CD4+ T cells may induce potent antitumor immune responses through interaction with antigen-presenting cells within the tumor microenvironment. Using a murine model of multiple myeloma, we demonstrated that adoptive transfer of idiotype-specific CD4+ T cells may elicit curative responses against established multifocal myeloma in bone marrow. This finding indicates that the myeloma bone marrow niche contains antigen-presenting cells that may be rendered tumoricidal. Given the complexity of the bone marrow microenvironment, the mechanistic basis of such immunotherapeutic responses is not known. Through a functional characterization of antitumor CD4+ T-cell responses within the bone marrow microenvironment, we found that killing of myeloma cells is orchestrated by a population of bone marrow-resident CD11b+F4/80+MHC-IIHigh macrophages that have taken up and present secreted myeloma protein. The present results demonstrate the potential of resident macrophages as powerful mediators of tumor killing within the bone marrow and provide a basis for novel therapeutic strategies against multiple myeloma and other malignancies that affect the bone marrow.

Deciphering the nexus between the tumor immune microenvironment and DNA methylation in subgrouping estrogen receptor-positive breast cancer

BACKGROUND

Based on variable DNA methylation (DNAm), estrogen receptor (ER)-positive breast cancer (BRCA) is composed of two major subtypes, with the hypomethylated subgroup displaying good survival. Evidence indicates that the tumor microenvironment (TME) plays an important role in tumor progression and metastasis; however, its role and biological characteristics in DNAm-based subtypes of ER-positive BRCA remain largely unknown.

METHODS

Transcriptome data and matched clinical information of BRCA were downloaded from the Cancer Genome Atlas. Immune (ISs) and stromal scores (SSs) of BRCA patients were calculated using the ESTIMATE algorithm. Inferred fractions of 22 types of infiltrating immune cells of BRCA were collected from the Cancer Immunome Atlas.

RESULTS

The hypomethylated ER-positive BRCA subtype displayed high ISs, echoing the finding that higher ISs are associated with good BRCA survival. In addition, we analyzed the differentially expressed genes between the hypo-high-IS and hyper-low-IS BRCA subtypes in ER-positive patients and identified a co-expressed gene module (i.e., red module) enriched in immune-related biological processes (e.g., leukocyte activation involved in immune response). Moreover, four hub genes (i.e., PLEK, CD53, EVI2B, and CD4) in this module showed significant association between their expression and ER-positive BRCA survival.

CONCLUSIONS

We found differences in the tumor immune microenvironment (TIME) between DNAm-based BRCA subgroups in ER-positive patients and identified a specific module and hub genes involved to these differences. These findings elucidate the immunological basis for ER-positive BRCA progression and classification and provide potential gene biomarkers and targets for ER-positive BRCA diagnosis and treatment.

Gold nanoparticles (AuNPs) impair LPS-driven immune responses by promoting a tolerogenic-like dendritic cell phenotype with altered endosomal structures

Dendritic cells (DCs) shape immune responses by influencing T-cell activation. Thus, they are considered both an interesting model for studying nano-immune interactions and a promising target for nano-based biomedical applications. However, the accentuated ability of nanoparticles (NPs) to interact with biomolecules may have an impact on DC function that poses an unexpected risk of unbalanced immune reactions. Here, we investigated the potential effects of gold nanoparticles (AuNPs) on DC function and the consequences for effector and memory T-cell responses in the presence of the microbial inflammatory stimulus lipopolysaccharide (LPS). Overall, we found that, in the absence of LPS, none of the tested NPs induced a DC response. However, whereas 4-, 8-, and 11 nm AuNPs did not modulate LPS-dependent immune responses, 26 nm AuNPs shifted the phenotype of LPS-activated DCs toward a tolerogenic state, characterized by downregulation of CD86, IL-12 and IL-27, upregulation of ILT3, and induction of class E compartments. Moreover, this DC phenotype was less proficient in promoting Th1 activation and central memory T-cell proliferation. Taken together, these findings support the perception that AuNPs are safe under homeostatic conditions; however, particular care should be taken in patients experiencing a current infection or disorders of the immune system.

CD80 Expression on Tumor Cells Alters Tumor Microenvironment and Efficacy of Cancer Immunotherapy by CTLA-4 Blockade

Cluster of differentiation (CD) 80 is mainly expressed in immune cells but can also be found in several types of cancer cells. This molecule may either activate or inhibit immune reactions. Here, we determined the immunosuppressive role of CD80 in the tumor microenvironment by CRISPR/Cas9-mediated deactivation of the corresponding gene in the mouse oncogenic TC-1 cell line. The tumor cells with deactivated CD80 (TC-1/dCD80-1) were more immunogenic than parental cells and induced tumors that gained sensitivity to cytotoxic T-lymphocyte antigen 4 (CTLA-4) blockade, as compared with the TC-1 cells. In vivo depletion experiments showed that the deactivation of CD80 switched the pro-tumorigenic effect of macrophages observed in TC-1-induced tumors into an anti-tumorigenic effect in TC-1/dCD80-1 tumors and induced the pro-tumorigenic activity of CD4⁺ cells. Moreover, the frequency of lymphoid and myeloid cells and the CTLA-4 expression by T helper (Th)17 cells were increased in TC-1/dCD80-1- compared with that in the TC-1-induced tumors. CTLA-4 blockade downregulated the frequencies of most immune cell types and upregulated the frequency of M2 macrophages in the TC-1 tumors, while it increased the frequency of lymphoid cells in TC-1/dCD80-1-induced tumors. Furthermore, the anti-CTLA-4 therapy enhanced the frequency of CD8⁺ T cells as well as CD4⁺ T cells, especially for a Th1 subset. Regulatory T cells (Treg) formed the most abundant CD4⁺ T cell subset in untreated tumors. The anti-CTLA-4 treatment downregulated the frequency of Treg cells with limited immunosuppressive potential in the TC-1 tumors, whereas it enriched this type of Treg cells and decreased the Treg cells with high immunosuppressive potential in TC-1/dCD80-1-induced tumors. The immunosuppressive role of tumor-cell-expressed CD80 should be considered in research into biomarkers for the prediction of cancer patients' sensitivity to immune checkpoint inhibitors and for the development of a tumor-cell-specific CD80 blockade.

Neoantigen vaccine platforms in clinical development: understanding the future of personalized immunotherapy

INTRODUCTION

Derived from genetic alterations, cancer neoantigens are proteins with novel amino acid sequences that can be recognized by the immune system. Recent evidence demonstrates that cancer neoantigens represent important targets of cancer immunotherapy. The goal of cancer neoantigen vaccines is to induce neoantigen-specific immune responses and antitumor immunity, while minimizing the potential for autoimmune toxicity. Advances in sequencing technologies, neoantigen prediction ?algorithms,? and other technologies have dramatically improved the ability to identify and prioritize cancer neoantigens. These advances have generated considerable enthusiasm for ?the ?development of neoantigen vaccines. Several neoantigen vaccine platforms are currently being evaluated in early phase clinical trials including the synthetic long peptide (SLP), RNA, dendritic cell (DC), and DNA vaccine platforms.

AREAS COVERED

In this review, we describe, evaluate the mechanism(s) of action, compare the advantages and disadvantages, and summarize early clinical experience with each vaccine platform. We provide perspectives on the future directions of the neoantigen vaccine field. All data are derived from PubMed and ClinicalTrials search updated in October 2020.

EXPERT OPINION

Although the initial clinical experience is promising, significant challenges to the success of neoantigen vaccines include limitations in neoantigen identification and the need to successfully target the immunosuppressive tumor microenvironment.

CD4 T Cell-Dependent Rejection of Beta-2 Microglobulin Null Mismatch Repair-Deficient Tumors

Inactivation of beta-2 microglobulin (B2M) is considered a determinant of resistance to immune checkpoint inhibitors (ICPi) in melanoma and lung cancers. In contrast, B2M loss does not appear to affect response to ICPis in mismatch repair-deficient (MMRd) colorectal tumors where biallelic inactivation of B2M is frequently observed. We inactivated B2m in multiple murine MMRd cancer models. Although MMRd cells would not readily grow in immunocompetent mice, MMRd B2m null cells were tumorigenic and regressed when treated with anti-PD-1 and anti-CTLA4. The efficacy of ICPis against MMRd B2m null tumors did not require CD8⁺ T cells but relied on the presence of CD4⁺ T cells. Human tumors expressing low levels of B2M display increased intratumoral CD4⁺ T cells. We conclude that B2M inactivation does not blunt the efficacy of ICPi in MMRd tumors, and we identify a unique role for CD4⁺ T cells in tumor rejection. SIGNIFICANCE: B2M alterations, which impair antigen presentation, occur frequently in microsatellite-unstable colorectal cancers. Although in melanoma and lung cancers B2M loss is a mechanism of resistance to immune checkpoint blockade, we show that MMRd tumors respond to ICPis through CD4⁺ T-cell activation.This article is highlighted in the In This Issue feature, p. 1601.

Nitric Oxide in Hematological Cancers: Partner or Rival?

Significance: Hematological malignancies represent the fourth most diagnosed cancer. Relapse and acquired resistance to anticancer therapy constitute two actual issues that need to be overcome. Nitric oxide (NO) plays a pivotal role in regulating cancer progression. At present, many studies are attempting to uncover the potentials of modulating NO levels to improve the efficacy of currently available treatments against lymphoma, leukemia, and myeloma. Recent Advances: It is becoming progressively clear that NO modulation may help hematological cancer management, either by targeting directly tumor cells or by driving the immune system to eliminate cancer cells. Critical Issues: NO is a dual molecule that can have a tumor-protecting or stimulating effect, depending on its local concentration. Moreover, NO is able to target a wide range of molecules involved in both cancer genesis and evolution. In this review, an overview of the recent findings regarding the pivotal role played by NO and nitric oxide synthase in cancer progression and anticancer therapy is presented, with particular focus on hematological malignancies. Future Directions: It is critical to establish the cancer-specific function of NO and critically drive its modulation to improve cancer management toward a personalized approach. This has a special importance in hematological tumors, where the urgency of finding eradicative therapies is constant. Antioxid. Redox Signal. 34, 383-401.

Designing the next-generation therapeutic vaccines to cure chronic hepatitis B: focus on antigen presentation, vaccine properties and effect measures

In the mid‐90s, hepatitis B virus (HBV)‐directed immune responses were for the first time investigated in detail and revealed suboptimal T‐cell responses in chronic HBV patients. Based on these studies, therapeutic vaccination exploiting the antigen presentation capacity of dendritic cells to prime and/or boost HBV‐specific T‐cell responses was considered highly promising. Now, 25 years later, it has not yet delivered this promise. In this review, we summarise what has been clinically tested in terms of antigen targets and vaccine forms, how the immunological and therapeutic effects of these vaccines were assessed and what major clinical and immunological findings were reported. We combine the lessons learned from these trials with the most recent insights on HBV antigen presentation, T‐cell responses, vaccine composition, antiviral and immune‐modulatory drugs and disease biomarkers to derive novel opportunities for the next generation of therapeutic vaccines designed to cure chronic HBV either alone or in combination therapy.

The Role of Tumor Microenvironment in Multiple Myeloma Development and Progression

Simple Summary

Multiple Myeloma (MM) is a hematologic malignancy caused by aberrant plasma cell proliferation in the bone marrow (BM) and constitutes the second most common hematological disease after non-Hodgkin lymphoma. The disease progression is drastically regulated by the immunosuppressive tumor microenvironment (TME) generated by soluble factors and different cells that naturally reside in the BM. This microenvironment does not remain unchanged and alterations favor cancer dissemination. Despite therapeutic advances over the past 15 years, MM remains incurable and therefore understanding the elements that control the TME in MM would allow better-targeted therapies to cure this disease. In this review, we discuss the main events and changes that occur in the BM milieu during MM development.

Abstract

Multiple myeloma (MM) is a hematologic cancer characterized by clonal proliferation of plasma cells in the bone marrow (BM). The progression, from the early stages of the disease as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) to MM and occasionally extramedullary disease, is drastically affected by the tumor microenvironment (TME). Soluble factors and direct cell–cell interactions regulate MM plasma cell trafficking and homing to the BM niche. Mesenchymal stromal cells, osteoclasts, osteoblasts, myeloid and lymphoid cells present in the BM create a unique milieu that favors MM plasma cell immune evasion and promotes disease progression. Moreover, TME is implicated in malignant cell protection against anti-tumor therapy. This review describes the main cellular and non-cellular components located in the BM, which condition the immunosuppressive environment and lead the MM establishment and progression.

Comprehensive genomic and immunophenotypic analysis of CD4 T cell infiltrating human triple-negative breast cancer

The aim of this study is to investigate the gene expression module of tumor-infiltrating CD4⁺T cells and its potential roles in modulating immune cell functions in triple-negative breast cancer. Differentially expressed genes were identified by comparison of the expression profile in CD4⁺T cells isolated from tumor tissues and peripheral blood of TNBC patients respectively. The differential expression analysis was conducted using R, and then the functional and pathway enrichment of the DEGs were analyzed using GSEA, followed by integrated regulatory network construction and genetic analysis of tumor-infiltrating immune cells based on a scientific deconvolution algorithm. As a result, abundant Treg and exhausted lymphocytes were detected, accompanied by largely decreased of effector/memory and cytotoxic T cells. Immune-related gene correlation analysis showed that the extent of follicular helper T cells gene expression signatures were inversely associated with those of CD4⁺ naive T cells and CD4⁺ memory resting T cells, but positively correlated with that of CD4⁺ memory activated T cells. In addition, we found five core genes including IFNG, CTLA4, FAS, CXCR6, and JUN were significantly over expressed in CD4⁺ TILs which may contribute to exhaustion of lymphocytes and participate in biological processes associated with regulation of chemotaxis. Study provides a comprehensive understanding of the roles of DEGs associated with the chemotactic and exhausted immunophenotypes of CD4⁺ TILs that are a valuable resource from which future investigation may be carried out to better understand the mechanisms that promote TNBC progression.

Prognostic Hub Genes in the Immune Microenvironment of Lung Adenocarcinoma by Estimation

BACKGROUND

The mortality of lung adenocarcinoma(LUAD) is high. Recent studies have found that the degree of immune infiltration and stromal cells in the tumour microenvironment or tumours makes a significant contribution to prognosis.

METHODS

During study, we screened differentially expressed genes (DEGs) of TCGA database for prognostic genes in LUAD immune microenvironment. Further, immune and stromal cells were quantified using ESTIMATE algorithm. To study the effects of immune and stromal cell-associated genes on the prognosis of LUAD, LUAD patients were divided into high and low groups according to their immune/ stromal scores. The obtained scores were found to be related to the phenotype and survival rate of LUAD patients. By selecting DEGs with high expression in immune and stromal cells, we performed functional enrichment analysis and found that most genes are associated with pathways of cancer, stimulus response and the MAPK signaling. The functions and enriched pathways of LUAD prognostic genes were shown by a protein-protein interaction (PPI) network. Nonetheless, an external database was used to validate the prognostic genes from the TCGA.

RESULTS

Prognostic genes were listed according to their expression position and protein function.

CONCLUSION

We provided a new targets for immunotherapy of LUAD, which further provides basic knowledge for future clinical research.

Robust Production of Merkel Cell Polyomavirus Oncogene Specific T Cells From Healthy Donors for Adoptive Transfer

Virus positive Merkel cell carcinoma (VP-MCC) is an aggressive but immunogenic skin malignancy driven by Merkel cell polyomavirus (MCPyV) T antigen (TAg). Since adoptive T cell transfer (ACT) can be effective against virus-driven malignancies, we set out to develop a methodology for generating MCPyV TAg specific T cells. MCPyV is a common, asymptomatic infection and virus-exposed healthy donors represent a potential source of MCPyV TAg specific T cells for ACT. Virus specific T cells were generated using monocyte-derived dendritic cells (moDCs) pulsed with MCPyV TAg peptide libraries and co-cultured with autologous T cells in supplemented with pro-inflammatory and homeostatic cytokines for 14 days. Specific reactivity was observed predominantly within the CD4⁺ T cell compartment in the cultures generated from 21/46 random healthy donors. Notably, responses were more often seen in donors aged 50 years and older. TAg specific CD4⁺ T cells specifically secreted Th1 cytokines and upregulated CD137 upon challenge with MCPyV TAg peptide libraries and autologous transduced antigen presenting cells. Expanded T cells from healthy donors recognized epitopes of both TAg splice variants found in VP-MCC tumors, and minimally expressed exhaustion markers. Our data show that MCPyV specific T cells can be expanded from healthy donors using methods appropriate for the manufacture of clinical grade ACT products.

Cells of the Innate and Adaptive Immune Systems in Kaposi's Sarcoma

Kaposi's sarcoma (KS) is an angioproliferative malignancy whose associated etiologic agent is the Kaposi's sarcoma-associated herpesvirus (KSHV). KS is the most prevalent malignancy among HIV-infected individuals globally and is considered an AIDS-defining malignancy. The different forms of KS including HIV-associated KS, iatrogenic (immunosuppression-related) KS, and classical KS in elderly males suggest that immune cell dysregulation is among the key components in promoting KS development in KSHV-infected individuals. It is therefore expected that different cell types of the immune system likely play distinct roles in promoting or inhibiting KS development. This narrative review is focused on discussing cells of the innate and adaptive immune systems in KSHV infection and KS pathogenesis, including how these cells can be useful in the control of KSHV infection and treatment of KS.

iNOS Expression by Tumor-Infiltrating Lymphocytes, PD-L1 and Prognosis in Non-Small-Cell Lung Cancer

Simple Summary

The role of Inducible Nitric Oxygen Synthase (iNOS) in the progression of human malignancies is obscure. We studied the expression patterns of iNOS in non-small-cell lung cancer. iNOS was expressed by cancer cells and cancer-associated fibroblasts. None of these patterns, however, are related to stage or prognosis. Extensive infiltration of the tumor stroma by iNOS-expressing tumor-infiltrating lymphocytes (^iNOS+TILs) occurred in 48% of cases. This was related to low Hypoxia-Inducible Factor 1α (HIF1α) and better overall survival. Expression of Programmed death-ligand 1 PD-L1, however, mitigates the beneficial effect of the presence of ^iNOS+TIL. An important role of iNOS in anti-neoplastic lymphocyte biology has been brought forward, supporting ^iNOS+TILs as putative immune response markers.

Abstract

Background: Inducible Nitric Oxygen Synthase (iNOS) promotes the generation of NO in tissues. Its role in tumor progression and immune response is unclear. Methods: The immunohistochemical expression patterns of iNOS were studied in a series of 98 tissue samples of non-small-cell lung carcinoma (NSCLC), in parallel with the expression of hypoxia and anaerobic metabolism markers, PD-L1 and tumor-infiltrating lymphocytes (TILs). Results: iNOS is expressed by cancer cells in 19/98 (19.4%), while extensive expression by cancer-associated fibroblasts occurs in 8/98 (8.2%) cases. None of these patterns relate to stage or prognosis. Extensive infiltration of the tumor stroma by iNOS-expressing TILs (^iNOS+TILs) occurs in 47/98 (48%) cases. This is related to low Hypoxia-Inducible Factor 1α (HIF1α), high PD-L1 expression and a better overall survival (p = 0.002). Expression of PD-L1, however, mitigates the beneficial effect of the presence of ^iNOS+TIL. Conclusions: Extensive expression of iNOS by TILs occurs in approximately 50% of NSCLCs, and this is significantly related to an improved overall survival. This brings forward the role of iNOS in anti-neoplastic lymphocyte biology, supporting ^iNOS+TILs as a putative marker of immune response. The value of this biomarker as a predictive and treatment-guiding tool for tumor immunotherapy demands further investigation.

TRIM59 suppresses NO production by promoting the binding of PIAS1 and STAT1 in macrophages

Macrophages, which can secret various inflammation mediators, have an essential role in tumor growth and metastasis. However, the mechanism(s) to regulate the production of inflammation mediator is not completely clear. Here we found that TRIM 59 could inhibit the production of NO and the expression of inducible nitric oxide synthase (iNOS), cytochrome c oxidase subunit2 (COX2) and TNFα. TRIM59 mediated suppression on nitric oxide (NO) production is through inhibiting the activation of JAK2-STAT1 signal pathway. In response to LPS, TRIM59 in macrophages was translocated from cytoplasm to nucleus and directly bound with STAT1. During this process, TRIM59 could recruit much more PIAS1 to bind with STAT1 to suppress the activation of STAT1. Finally, TRIM59 modified macrophages could promote tumor growth. Thus, TRIM59 mediated suppression on NO production by promoting the binding of PIAS1 and STAT1 in macrophages may regulate tumor growth.