A rare population of tumor antigen-specific CD4+CD8+ double-positive αβ T lymphocytes uniquely provide CD8-independent TCR genes for engineering therapeutic T cells

Flammulina velutipes polysaccharide exerts immunomodulatory function involving RSAD2 to regulate the NF-κB/MAPK signaling pathway in RAW264.7 macrophage cells and in mouse spleen cells

There are ongoing efforts to explore the potential of natural bioactive substances including polysaccharides in immunological regulation and understand the mechanisms under their immune-regulating function. In this study, a polysaccharide from Flammulina velutipes (FVP-1) exhibited immunomodulatory in RAW264.7 macrophage cells and mouse spleen cells. FVP-1 increased the secretion of cytokines (like TNF-α, IL-6 and IL-1β) and their mRNA expression, upregulated the transcription and translation expression of COX-2 and iNOS, and enhanced the release of reactive oxygen species the phagocytic activity in macrophages, thereby promoting the maturation and transformation of certain lymphocytes. All these functions of FVP-1 depended to some extent on its concentration. The RSAD2 effector was involved in the immunomodulatory function of FVP-1 towards macrophages and mouse splenocytes, through mediating FVP-1's activation and regulation of the NF-κB/MAPK signaling pathway. These findings indicate the potential of FVP-1 as a natural immunomodulator and approach for improving immune function.

Extrathymic CD8 and CD4 Double Positive T Cells Presenting Vigorous HBV-Specific Responses Accelerate HBV Clearance

Hepatitis B virus (HBV) infection is a worldwide health problem. Both CD4+ and CD8 + T cells play crucial roles in HBV clearance from acute patients. Nevertheless, an extrathymic CD4 and CD8 double positive T (DPT) cell subset have been reported earlier, the function of these cells in HBV infection is still poorly understood. Herein, peripheral blood mononuclear cells were collected from hepatitis B patients. HBV model mice were established via hydrodynamic injection (HDI) of pAAV-HBV1.2 plasmid. T cells subsets were analyzed with flow cytometry. We found that in acute HBV infection extrathymic DPT cells were significantly increased in acute patients and HDI-based HBV model mice. Unlike thymic DPT cells, these extrathymic DPT cells activated with a CD44 + CD62L+ central memory phenotype. Furthermore, in vitro cultured DPT cells showed the capability to rapidly proliferate and produce multi cytokines after stimulation with HBV peptides. The performance of adoptive transfer depicted that DPT cells were able to migrate into the liver. Immunohistochemistry data from liver biopsies of patients showed that DPT cells were more prone to detection in acute tissue. Purified DPT cells could efficiently kill HBV peptide-loaded hepatocytes in a cytotoxicity assay, and the frequency of DPT cells were reversely correlated with HBV clearance in model mice. Importantly, the transferred DPT cells accelerated the clearance of HBV in mice. Collectively, our study revealed that extrathymic DPT cells are an important immune subset, contributing to viral clearance during HBV infection, which may benefit cure of chronic hepatitis B.

Thermosensitive hyaluronic acid-manganese-capsaicin complex nanogel improving NKG2D/CAR-T melanoma treatment through adjusting tumor microenvironment

Intratumorally injection of CAR-T cells to treat melanoma can reduce the incidence of systemic side effects and ensure an adequate concentration of CAR-T cells. However, few targeting ligands and hostile tumor microenvironment (TME) inhibit the CAR-T cells' survival and infiltration. An in situ hyaluronic acid‑manganese-capsaicin complex nanogel (HA-Mn-CAP Gel) was designed by forming complex nanogel based on the main skeleton material of hyaluronic acid (HA). It targeted CD44 and TRPV1 receptors through HA and CAP, concentrated and released Mn at melanoma, subsequently relieving the hypoxia in the tumor and increasing the expression of CAR-T cells' specific ligands. Cell experiments showed that HA-Mn-CAP Gel significantly enhanced the expression of representative NKG2D ligands (MICA/B and ULBP2/5/6) >2.7 times on A375 melanoma cells. Sequential administration of HA-Mn-CAP Gel and NKG2D/CAR-T increased the tumor inhibition rate about 1.5 times that of the NKG2D/CAR-T group in melanoma-bearing NSG mice. The results of immunohistochemistry and immunofluorescence assays showed that the combined HA-Mn-CAP Gel and NKG2D/CAR-T significantly increased the proliferation and infiltration of T cells, especially for CD8+ cells. Therefore, the new promising strategy of increasing the target ligand expression and adjusting TME before administering CAR-T cells is suitable for treating solid tumors.

NK Receptor Signaling Lowers TCR Activation Threshold, Enhancing Selective Recognition of Cancer Cells by TAA-Specific CTLs

Cytotoxic CD8+ T lymphocyte (CTL) recognition of non-mutated tumor-associated antigens (TAA), present on cancer cells and also in healthy tissues, is an important element of cancer immunity, but the mechanism of its selectivity for cancer cells and opportunities for its enhancement remain elusive. In this study, we found that CTL expression of the NK receptors (NKR) DNAM1 and NKG2D was associated with the effector status of CD8+ tumor-infiltrating lymphocytes and long-term survival of patients with melanoma. Using MART1 and NY-ESO-1 as model TAAs, we demonstrated that DNAM1 and NKG2D regulate T-cell receptor (TCR) functional avidity and set the threshold for TCR activation of human TAA-specific CTLs. Superior co-stimulatory effects of DNAM1 over CD28 involved enhanced TCR signaling, CTL killer function, and polyfunctionality. Double transduction of human CTLs with TAA-specific TCR and NKRs resulted in strongly enhanced antigen sensitivity, without a reduction in antigen specificity and selectivity of killer function. In addition, the elevation of NKR ligand expression on cancer cells due to chemotherapy also increased CTL recognition of cancer cells expressing low levels of TAAs. Our data help explain the ability of self-antigens to mediate tumor rejection in the absence of autoimmunity and support the development of dual-targeting adoptive T-cell therapies that use NKRs to enhance the potency and selectivity of recognition of TAA-expressing cancer cells.

NK Receptors Replace CD28 As the Dominant Source of Signal 2 for Cognate Recognition of Cancer Cells by TAA-specific Effector CD8+ T Cells

CD28-driven "signal 2" is critical for naïve CD8+ T cell responses to dendritic cell (DC)-presented weak antigens, including non-mutated tumor-associated antigens (TAAs). However, it is unclear how DC-primed cytotoxic T lymphocytes (CTLs) respond to the same TAAs presented by cancer cells which lack CD28 ligands. Here, we show that NK receptors (NKRs) DNAM-1 and NKG2D replace CD28 during CTL re-activation by cancer cells presenting low levels of MHC I/TAA complexes, leading to enhanced proximal TCR signaling, immune synapse formation, CTL polyfunctionality, release of cytolytic granules and antigen-specific cancer cell killing. Double-transduction of T cells with recombinant TCR and NKR constructs or upregulation of NKR-ligand expression on cancer cells by chemotherapy enabled effective recognition and killing of poorly immunogenic tumor cells by CTLs. Operational synergy between TCR and NKRs in CTL recognition explains the ability of cancer-expressed self-antigens to serve as tumor rejection antigens, helping to develop more effective therapies.

miR-4433a-3p promotes granulosa cell apoptosis by targeting peroxisome proliferator-activated receptor alpha and inducing immune cell infiltration in polycystic ovarian syndrome

BACKGROUND

Granulosa cell (GC) proliferation and apoptosis are critical events of the ovum energy supply, which lead to follicular growth retardation or atresia, and various ovulatory obstacles, eventually resulting in the development of ovarian disorders such as polycystic ovarian syndrome (PCOS). Apoptosis and dysregulated miRNA expression in GCs are manifestations of PCOS. miR-4433a-3p has been reported to be involved in apoptosis. However, there is no study reporting the roles of miR-4433a-3p in GC apoptosis and PCOS progression.

METHODS

miR-4433a-3p and peroxisome proliferator-activated receptor alpha (PPAR-α) levels in GCs of PCOS patients or in tissues of a PCOS rat model were examined by quantitative polymerase chain reaction and immunohistochemistry. Bioinformatics analyses and luciferase assays were used to examine the association between miR-4433a-3p and PPAR-α, as well as PPAR-α and immune cell infiltration, in PCOS patients.

RESULTS

miR-4433a-3p expression in GCs of PCOS patients was increased. miR-4433a-3p overexpression inhibited the growth of the human granulosa-like tumor cell line (KGN) and promoted apoptosis, while co-treatment with PPAR-α and miR-4433a-3p mimic rescued miR-4433a-3p-induced apoptosis. PPAR-α was a direct target of miR-4433a-3p and its expression was decreased in PCOS patients. PPAR-α expression was also positively correlated with the infiltration of activated CD4+ T cells, eosinophils, B cells, gamma delta T cells, macrophages, and mast cells, but negatively correlated with the infiltration of activated CD8+ T cells, CD56+ bright natural killer cells, immature dendritic cells, monocytes, plasmacytoid dendritic cells, neutrophils, and type 1 T helper cells in PCOS patients.

CONCLUSION

The miR-4433a-3p/PPAR-α/immune cell infiltration axis may function as a novel cascade to alter GC apoptosis in PCOS.

Peptide-functionalized zinc oxide nanoparticles for the selective targeting of breast cancer expressing placenta-specific protein 1

Functionalized metal oxide nanoparticles (NPs) have demonstrated specific binding affinity to antigens or receptors presented on the cancer cell surface, favouring selective targeting and minimizing side effects during the chemotherapy. Placenta-specific protein 1 (PLAC-1) is a small cell surface protein overexpressed in certain types of breast cancer (BC); therefore, it can be used as a therapeutic target. The objective of this study is to develop NPs that can bind PLAC-1 and hence can inhibit the progression and metastatic potential of BC cells. Zinc oxide (ZnO) NPs were coated with a peptide (GILGFVFTL), which possesses a strong binding ability to PLAC-1. The physical attachment of the peptide to ZnO NPs was verified through various physicochemical and morphological characterization techniques. The selective cytotoxicity of the designed NPs was investigated using PLAC-1-bearing MDA-MB 231 human BC cell line and compared to LS-180 cells that do not express PLAC-1. The anti-metastatic and pro-apoptotic effects of the functionalized NPs on MDA-MB 231 cells were examined. Confocal microscopy was used to investigate the mechanism of NPs uptake by MDA-MB 231 cells. Compared to non-functionalized NPs, peptide functionalization significantly improved the targeting and uptake of the designed NPs by PLAC-1-expressing cancer cells with significant pro-apoptotic and anti-metastatic effects. The uptake of peptide functionalized ZnO NPs (ZnO-P NPs) occurred via peptide-PLAC1 interaction-assisted clathrin-mediated endocytosis. These findings highlight the potential targeted therapy of ZnO-P NPs against PLAC-1-expressing breast cancer cells.

Intratumoral therapies and in-situ vaccination for melanoma

Skin cancers are among the most physically accessible malignancies, so local delivery of a medication into the tumor, so-called intratumoral therapy, is an appealing route of drug administration. Intratumoral therapies have the potential to increase local drug concentration and/or attract immune cells to the local tumor microenvironment, possibly with fewer systemic side effects. A wide array of intratumoral agents have been studied to date in patients with advanced melanoma, including chemotherapeutic drugs, immune modulating agents, and cancer-directed vaccines. In this review, we will summarize the key pre-clinical and clinical data supporting the use of intratumoral therapy for advanced unresectable and metastatic melanoma. First, we will discuss the history of intratumoral immunotherapy for the treatment of melanoma and the various agents studied to date. Second, we will explore how intratumoral therapies can constitute an in situ vaccine, potentially leading to disease control both locally and systemically. Finally, we will highlight opportunities in the field and key future directions.

Identification of Claudin 6-specific HLA class I- and HLA class II-restricted T cell receptors for cellular immunotherapy in ovarian cancer

Adoptive cell therapy (ACT) is one of promising immunotherapies for cancer patients by providing a large amount of cancer antigen-specific effector T cells that can be manufactured rapidly by ex vivo gene engineering. To provide antigen-specificity to patients’ autologous T cells in a short-term culture, T-cell receptors (TCRs) or chimeric antigen receptors (CARs) are transduced to bulk T cells. Because of intra- and inter-tumoral heterogeneity in tumor antigen expression, a repertoire of TCR or CAR genes targeting a wide range of tumor antigens are required for a broad and effective treatment by ACT. Here, we characterized immunogenicity of claudin 6 (CLDN6) in ovarian cancer patients and identified specific TCR genes from CD8⁺ and CD4⁺ T cells. CLDN6 protein was frequently expressed on EpCAM⁺ ovarian cancer cells but not CD45⁺ lymphocytes in tumor ascites of ovarian cancer patients. Spontaneous CLDN6-specific CD4⁺ and CD8⁺ T-cell response was detected in peripheral blood mononuclear cells (PBMCs) from 1 out of 17 ovarian cancer patients. HLA-A*02:01 (A2) and DR*04:04 (DR4)-restricted TCR genes were isolated from CLDN6-specific CD8⁺ and CD4⁺ T cells, respectively. T cells that were engineered with A2-restricted TCR gene recognized and killed A2⁺CLDN6⁺ cancer cells. DR4-restricted TCR-transduced T cells directly recognized DR4⁺CLDN6⁺-overexpressed cancer cells. Our results demonstrate that these CLDN6-specific TCR genes are useful as therapeutic genes for ACT to patients with ovarian and other solid tumors expressing CLDN6.

Development of a nonhuman primate challenge model to evaluate CD8+ T cell responses to an adenovirus-based vaccine expressing SIV proteins upon repeat-dose treatment with checkpoint inhibitors

Targeting immune checkpoint receptors expressed in the T cell synapse induces active and long-lasting antitumor immunity in preclinical tumor models and oncology patients. However, traditional nonhuman primate (NHP) studies in healthy animals have thus far demonstrated little to no pharmacological activity or toxicity for checkpoint inhibitors (CPIs), likely due to a quiescent immune system. We developed a NHP vaccine challenge model in Mauritius cynomolgus monkey (MCMs) that elicits a strong CD8⁺ T cell response to assess both pharmacology and safety within the same animal. MHC I-genotyped MCMs were immunized with three replication incompetent adenovirus serotype 5 (Adv5) encoding Gag, Nef and Pol simian immunodeficiency virus (SIV) proteins administered 4 weeks apart. Immunized animals received the anti-PD-L1 atezolizumab or an immune checkpoint-targeting bispecific antibody (mAbX) in early development. After a single immunization, Adv5-SIVs induced T-cell activation as assessed by the expression of several co-stimulatory and co-inhibitory molecules, proliferation, and antigen-specific T-cell response as measured by a Nef-dependent interferon-γ ELIspot and tetramer analysis. Administration of atezolizumab increased the number of Ki67⁺ CD8⁺ T cells, CD8⁺ T cells co-expressing TIM3 and LAG3 and the number of CD4⁺ T cells co-expressing 4–1BB, BTLA, and TIM3 two weeks after vaccination. Both atezolizumab and mAbX extended the cytolytic activity of the SIV antigen-specific CD8⁺ T cell up to 8 weeks. Taken together, this vaccine challenge model allowed the combined study of pharmacology and safety parameters for a new immunomodulatory protein-based therapeutic targeting CD8⁺ T cells in an NHP model.

Shaping Immune Responses in the Tumor Microenvironment of Ovarian Cancer

Reciprocal signaling between immune cells and ovarian cancer cells in the tumor microenvironment can alter immune responses and regulate disease progression. These signaling events are regulated by multiple factors, including genetic and epigenetic alterations in both the ovarian cancer cells and immune cells, as well as cytokine pathways. Multiple immune cell types are recruited to the ovarian cancer tumor microenvironment, and new insights about the complexity of their interactions have emerged in recent years. The growing understanding of immune cell function in the ovarian cancer tumor microenvironment has important implications for biomarker discovery and therapeutic development. This review aims to describe the factors that shape the phenotypes of immune cells in the tumor microenvironment of ovarian cancer and how these changes impact disease progression and therapy.

Exploration of a Robust and Prognostic Immune Related Gene Signature for Cervical Squamous Cell Carcinoma

Background: Cervical squamous cell carcinoma (CESC) is one of the most frequent malignancies in women worldwide. The level of immune cell infiltration and immune-related genes (IRGs) can significantly affect the prognosis and immunotherapy of CESC patients. Thus, this study aimed to identify an immune-related prognostic signature for CESC.

Methods: TCGA-CESC cohorts, obtained from TCGA database, were divided into the training group and testing group; while GSE44001 dataset from GEO database was viewed as external validation group. ESTIMATE algorithm was applied to evaluate the infiltration levels of immune cells of CESC patients. IRGs were screened out through weighted gene co-expression network analysis (WGCNA). A multi-gene prognostic signature based on IRGs was constructed using LASSO penalized Cox proportional hazards regression, which was validated through Kaplan–Meier, Cox, and receiver operating characteristic curve (ROC) analyses. The abundance of immune cells was calculated using ssGSEA algorithm in the ImmuCellAI database, and the response to immunotherapy was evaluated using immunophenoscore (IPS) analysis and the TIDE algorithm.

Results: In TCGA-CESC cohorts, higher levels of immune cell infiltration were closely associated with better prognoses. Moreover, a prognostic signature was constructed using three IRGs. Based on this given signature, Kaplan–Meier analysis suggested the significant differences in overall survival (OS) and the ROC analysis demonstrated its robust predictive potential for CESC prognosis, further confirmed by internal and external validation. Additionally, multivariate Cox analysis revealed that the three IRGs signature served as an independent prognostic factor for CESC. In the three-IRGs signature low-risk group, the infiltrating immune cells (B cells, CD4/8 + T cells, cytotoxic T cells, macrophages and so on) were much more abundant than that in high-risk group. Ultimately, IPS and TIDE analyses showed that low-risk CESC patients appeared to present with a better response to immunotherapy and a better prognosis than high-risk patients.

Conclusion: The present prognostic signature based on three IRGs (CD3E, CD3D, LCK) was not only reliable for survival prediction but efficient to predict the clinical response to immunotherapy for CESC patients, which might assist in guiding more precise individual treatment in the future.

Antitumour metastasis and the antiangiogenic and antitumour effects of a Eimeria stiedae soluble protein

Some protozoa (Plasmodium falciparum, Toxoplasma gondii, etc) are used to treat cancer because they can improve tumour-induced immunosuppression. This study aims to evaluate the antitumour effect of Eimeria stiedae oocyst soluble protein (ESSP). ESSP was extracted, and mice were injected with 5 × 10⁵ CT26 cells in the right axilla, and then, 50 μg of ESSP was intraperitoneally injected for 5 continuous days. The effect of ESSP on tumour immunity was detected by flow cytometry 25 days after the CT26 inoculation. The results showed that ESSP can inhibit the growth of CT26 subcutaneous tumours; significantly increase the expression of MHC I, MHC II, CD80 and CD86 on the surface of splenic dendritic cells; and enhance the level of IL-12 secretion. ESSP induced an increase in the number of NK cells in the mouse spleen, and the levels of IFN-γ and CD107 were upregulated in the NK cells and CD8⁺ T cells. The number of metastatic nodules in the lung tumours in the mice was significantly reduced, and the number of tubes, area of the loops and total length of the tubes were significantly reduced. ESSP enhances the antitumour immune response and inhibits tumour growth, metastasis and angiogenesis.

Immunotherapy for sarcomas: new frontiers and unveiled opportunities

Sarcomas are a rare malignancy of mesenchymal tissues, comprizing a plethora of unique subtypes, with more than 60 types. The sheer heterogeneity of disease phenotype makes this a particularly difficult cancer to treat. Radiotherapy, chemotherapy and surgery have been employed for over three decades and, although effective in early disease (stages I–II), in later stages, where metastatic tumors are present, these treatments are less effective. Given the spectacular results obtained by cancer immunotherapy in a variety of solid cancers and leukemias, there is now a great interest in appliying this new realm of therapy for sarcomas. The widespread use of immunotherapy for sarcoma relies on immuno-profiling of subtypes, immunomonitoring for prognosis, preclinical studies and insight into the safety profile of these novel therapies. Herein, we discuss preclinical and clinical data highlighting how immunotherapy is being used in soft tissue sarcoma and bone sarcomas.

Fidelity of human ovarian cancer patient-derived xenografts in a partially humanized mouse model for preclinical testing of immunotherapies

Background

Immune checkpoint blockers (ICBs) have been approved by the Food and Drug Administration to be used alone in front-line therapies or in combination with other regimens for certain advanced cancers. Since ICB only works in a subset of patients and has limited efficacy in treating ovarian cancer (OVC), developing preclinical models that help to understand which patients may derive benefit from ICB would be of tremendous benefit in OVC.

Methods

Here, we generated preclinical human OVC models from freshly resected tumors, which include six patient-derived xenografts (PDXs) from six different patient tumors, three transplantable OVC PD spheroid lines (PD-sphs), and 3 cell lines (PD-CLs). We tested the therapeutic combination of anti-PD1/CTLA4 antibodies with (1) autologous tumor-associated leukocytes (TALs) on the growth of PD-sphs in a coculture system in vitro, (2) with adoptively transferred autologous peripheral blood mononuclear cells or TALs in patient-derived OVC models using partially humanized mice, NSG-HHDxSGM3 (N-HSGM3).

Results

We show that PD-1 and CTLA-4 dual blockade when combined with autologous TALs effectively reduced PD-sph number in a co-culture system and led to regression of established PD-CLs and PDXs in the N-HSGM3 mice. Combinatorial PD-1 and CTLA-4 blockade increased the frequency and function of tumor-specific CD8 T cells. These CD8 T cells persisted in the tumor microenvironment, exhibited memory phenotype and protected animals from tumor growth on tumor rechallenge. Gene expression analysis of tumors resistant to dual PD1/CTLA4 blockade treatment identified upregulation of antigen processing and presentation pathways and downregulation of extracellular matrix organization genes.

Conclusions

These findings describe a novel platform for developing patient-derived preclinical tumor models suitable for rationally testing combinatorial ICB in the context of autologous tumor-reactive T cells. This platform can be further developed for testing additional targeted therapies relevant to OVC.

New directions in chimeric antigen receptor T cell [CAR-T] therapy and related flow cytometry

Chimeric antigen receptor (CAR) T cells provide a promising approach to the treatment of hematologic malignancies and solid tumors. Flow cytometry is a powerful analytical modality, which plays an expanding role in all stages of CAR T therapy, from lymphocyte collection, to CAR T cell manufacturing, to in vivo monitoring of the infused cells and evaluation of their function in the tumor environment. Therefore, a thorough understanding of the new directions is important for designing and implementing CAR T-related flow cytometry assays in the clinical and investigational settings. However, the speed of new discoveries and the multitude of clinical and preclinical trials make it challenging to keep up to date in this complex field. In this review, we summarize the current state of CAR T therapy, highlight the areas of emergent research, discuss applications of flow cytometry in modern cell therapy, and touch upon several considerations particular to CAR detection and assessing the effectiveness of CAR T therapy.