Tumor Cell Vaccine Research Articles

Effect of FAPα-expressing tumor cell vaccine with PD-1 mAb on its efficacy in mice colorectal cancer model.

e14615 Background: Colorectal cancer (CRC) is the third prevalent malignant tumor all over the world, and many cases are metastatic at diagnosis. Immunotherapy emerges a promising treatment in CRC. However, anti-PD-1 monotherapy alone has not yielded a clinical benefit in majority of these patients. Therefore, combination therapy is necessary to overcome this limitation. Previously, we have developed a FAPα-expressing tumor vaccine and demonstrated its anti-tumor effects by reversing of immunosuppressive tumor microenvironment (TME). In the current study, we hypothesized that combination therapy could enhance the effect of anti-PD1 therapy. Methods: FAPα-expressing CT26 cells were produced as previously described. To establish xenograft tumor model, CT26 cells were injected into left flank of BALB/c mice. Anti-PD-1 monoclonal antibodies(mAb) were injected intraperitoneally twice weekly up to 5 injections. FAPα-vaccines were injected subcutaneously around tumors weekly up to 3 injections. Histological sections of tumours were analysed by H&E staining and immunofluorescence. Flow cytometric analysis was done using an FACSCalibur (BD) and analyzed using FlowJo software (TreeStar). Gene expression profile in TME was analyzed by bulk RNA sequencing. Results: In mice xenograft CT26 tumor model, either anti-PD-1 immunotherapy or FAPα tumor cell vaccine produced suppression of CT26 tumor growth compared with the control group. However, combining anti-PD-1 mAb and FAPα-expressing tumor cell vaccine elicited the most remarkable anti-tumor effect and induced the most pronounced tumor growth suppression among all groups. In combination therapy group of the vaccine and PD-1 mAb, there were significantly more infiltrated lymphocytes and less FAPα+ fibroblasts. Flow cytometry demonstrated that the combination therapy promoted M1 macrophage polarization with a reduction of M2-like tumor associated macrophages (TAMs) and an increase of M1-like TAMs. This polarization was in consistent with the reduced level of IL-10 that is predominant cytokine secreted by M2 macrophages. A reduction of myeloid-derived suppressor cells (MDSCs) in the TME were also observed. Using bulk RNAseq we observed a set of immune related genes upregulated following combination therapy, including innate immune response, antigen presentation, lymphatic cells and recruitment and T cells activation. Decreased secretion of immune inhibitory chemokines (eg, CXCL12, IL-10, TGFβ) was also found by ELISA in tumors from mice treated with combination therapy. Conclusions: Our preliminary results suggested that combination therapy of FAPα-expressing tumor vaccine and anti-PD-1 therapy is a promising way to improve the efficacy of immunotherapy through modulation of immunosuppressive TME. In the future, more research is needed to further elucidate mechanism and clinical value of this combination approach.

Augmented interferon regulatory factor 7 axis in whole tumor cell vaccines prevents tumor recurrence by inducing interferon gamma-secreting B cells

ABSTRACT Among cancer immunotherapy, which has received great attention in recent years, cancer vaccines can potentially prevent recurrent tumors by using the exquisite power and specificity of the immune system. Specifically, whole tumor cell vaccines (WTCVs) based on surgically resected tumors have been considered to elicit robust anti-tumor immune responses by exposing various tumor-associated antigens to host immunity. However, most tumors have little immunogenicity because of immunoediting by continuous interactions with host immunity; thus, preparing WTCVs based on patient-derived non-modified tumors cannot prevent tumor onset. Hence, the immunogenicity of tumor cells must be improved for effective WTCVs. In this study, we indicate the importance of the interferon regulatory factor 7 (Irf7) axis, including Irf7 and its downstream factors, within tumor cells in regulating immunogenicity. Indeed, WTCVs that augmented the Irf7 axis have exerted remarkable recurrence-preventive effects when vaccinated after tumor inactivation by radiation. Most notably, vaccination with murine colon cancer cells that enhanced the Irf7 axis prevented the development of challenged tumors in all mice and resulted in a 100% survival rate during the observation period. Furthermore, the mechanism leading to vaccine effectiveness was mediated by interferon-gamma-producing B cells. This study provides novel insights into how to enhance tumor immunogenicity and use WTCVs as recurrence prophylaxis.

Advanced Oxidation Nanoprocessing Boosts Immunogenicity of Whole Tumor Cells.

Whole tumor cells expressing a wide array of tumor antigens are considered as a highly promising source of antigens for cancer vaccines. However, simultaneously preserving the antigen diversity, improving immunogenicity, and eliminating the potential tumorigenic risk of whole tumor cells are highly challenging. Inspired by the recent progress in sulfate radical-based environmental technology, herein, an advanced oxidation nanoprocessing (AONP) strategy is developed for boosting the immunogenicity of whole tumor cells. The AONP is based on the activation of peroxymonosulfate by ZIF-67 nanocatalysts to produce SO4 -∙ radicals continuously, leading to sustained oxidative damage to tumor cells and consequently extensive cell death. Importantly, AONP causes immunogenic apoptosis as evidenced by the release of a series of characteristic damage associated molecular patterns and at the same time maintains the integrity of cancer cells, which is critical to preserve the cellular components and thus maximize the diversity of antigens. Finally, the immunogenicity of AONP-treated whole tumor cells is evaluated in a prophylactic vaccination model, demonstrating significantly delayed tumor growth and increased survival rate of live tumor-cell-challenged mice. It is expected that the developed AONP strategy would pave the way to develop effective personalized whole tumor cell vaccines in future.

Status Quo and Development of Immunotherapy for Hepatocellular Carcinoma

Liver cancer is a serious global health problem and a common cause of cancer-related death. Hepatocellular carcinoma (HCC) is a common pathological type of liver cancer. The clinical symptoms of early HCC tend to be not obvious and 50% of HCC patients are already in the advanced stage by the time they are diagnosed. Systemic therapy is recommended for the treatment of advanced HCC. With the development of molecular targeted drugs (sorafenib and lenvatinib), some progress has been made in the systemic treatment of advanced HCC, but there is only modest benefit for the survival of HCC patients. In recent years, the emergence of immune checkpoint inhibitors has changed the overall outlook of HCC treatment, providing more possibilities for precise treatment of HCC and showing better treatment outcomes. In particular, the combination therapy of atezolizumab and bevacizumab significantly improved the survival outcomes in HCC patients. In addition, adoptive cell therapy, tumor vaccine, oncolytic viruses, and nonspecific immunotherapy have also emerged as strategies for immunotherapy. Herein, the status quo and development of HCC immunotherapy are reviewed.

Targeting myeloid-derived suppressor cells in combination with tumor cell vaccination predicts anti-tumor immunity and breast cancer dormancy: an in silico experiment

Among the different breast cancer subsets, triple-negative breast cancer (TNBC) has the worst prognosis and limited options for targeted therapies. Immunotherapies are emerging as novel treatment opportunities for TNBC. However, the surging immune response elicited by immunotherapies to eradicate cancer cells can select resistant cancer cells, which may result in immune escape and tumor evolution and progression. Alternatively, maintaining the equilibrium phase of the immune response may be advantageous for keeping a long-term immune response in the presence of a small-size residual tumor. Myeloid-derived suppressor cells (MDSCs) are activated, expanded, and recruited to the tumor microenvironment by tumor-derived signals and can shape a pro-tumorigenic micro-environment by suppressing the innate and adaptive anti-tumor immune responses. We recently proposed a model describing immune-mediated breast cancer dormancy instigated by a vaccine consisting of dormant, immunogenic breast cancer cells derived from the murine 4T1 TNBC-like cell line. Strikingly, these 4T1-derived dormant cells recruited fewer MDSCs compared to aggressive 4T1 cells. Recent experimental studies demonstrated that inactivating MDSCs has a profound impact on reconstituting immune surveillance against the tumor. Here, we developed a deterministic mathematical model for simulating MDSCs depletion from mice bearing aggressive 4T1 tumors resulting in immunomodulation. Our computational simulations indicate that a vaccination strategy with a small number of tumor cells in combination with MDSC depletion can elicit an effective immune response suppressing the growth of a subsequent challenge with aggressive tumor cells, resulting in sustained tumor dormancy. The results predict a novel therapeutic opportunity based on the induction of effective anti-tumor immunity and tumor dormancy.

Abstract 6800: Unique autologous cancer vaccine comprised of irradiated whole tumor cells and MBTA (rWTC-MBTA) triggers antitumor immune response to prevent metastasis

Abstract Despite the advances made in cancer treatment over the past decades, one statistic has remained unchanged: metastatic cancer accounts for 90 percent of annual cancer deaths in the United States. Our group previously demonstrated that an autologous whole tumor cell vaccine (rWTC-MBTA: irradiated autologous whole tumor cells pulsed with Mannan-BAM, TLR ligands, and anti-CD40 antibody) had a potent anti-tumor immune response and prolonged survival in a mouse colon carcinoma model. To investigate whether rWTC-MBTA would work in “cold” tumor models, we evaluated the vaccine’s effect on preventing and treating tumor metastasis in 4T1 breast tumors. Our data showed that vaccinated mice could significantly prevent lung metastasis in both intravenous injection and mammary pad subcutaneous implantation animal models. Further, we used another metastasis model that more closely mimics clinical practice by resecting the primary tumor after metastasis development. The data showed that vaccinated mice could prevent tumor recurrence, increase T-cell infiltration in the metastatic tumor, and prolong the survival curve. The mechanistic investigation by immunophenotyping revealed that rWTC-MBTA vaccination induced both effector memory (CD44+CD62L−) and center memory (CD44+CD62L+) T cells as well as increased overall CD4+ and CD8+ T-cell count while depletion experiments demonstrated that CD8+ T cells were required for vaccine efficacy. Isolated splenocytes co-cultured with 4T1 cells showed rWTC-MBTA significantly increased T-cell mediated cytotoxicity through TNF-a and IFN-γ in CD107a+CD4+ T cells and Granzyme B and IFN-γ in CD107a+CD8+ T cells. In all experiments, vaccination exerted negligible systemic toxicity. Collectively, our study demonstrates that the rWTC-MBTA vaccine is a safe and promising therapeutic option to prevent and treat tumor metastasis by triggering an antitumor immune response. Citation Format: Juan Ye, Herui Wang, Mitchell Sun, Ondrej Uher, Mark R. Gilbert, Karel Pacak, Zhengping Zhuang, Rogelio Medina, Samik Chakraborty, Jan Zenka. Unique autologous cancer vaccine comprised of irradiated whole tumor cells and MBTA (rWTC-MBTA) triggers antitumor immune response to prevent metastasis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6800.

Abstract 6791: Inovative in vivo (in ovo) CAM model to predict efficacy and mode of action of a new antitumor vaccine stc-1010 on human colorectal adenocarcinoma

Abstract BACKGROUND: Colorectal cancer (CRC) is the second-most deadly cancer. Therapeutic resistance to immuno-oncology drives the need for new treatments. Stimulated tumor cell (STC) vaccine (Brenus Pharma) is composed of selected tumor cell lines, stimulated to overexpress tumor-associated or tumor-specific antigens and neoantigens including resistance factors. Haptenization of these proteins forms an immunogenic complex which stimulate the immune system to recognize and target the patient’s tumor cells expressing same resistance factors. We report in vivo results of STC-1010 vaccine, on human CRC adenocarcinoma from HT29 cell using chorioallantoic membrane (CAM) assay developed by Inovotion in immune reactive model. METHODS: This study was carried out in 2 steps: Firstly, three batches of naïve chicken embryos were stimulated by injections of STC1010 at Embryo Development Day (EDD) 11 and EDD13. At EDD18 of each batch, chicken peripheral blood mononuclear cells (PBMCs) were collected and used as anti-tumor reagent to treat respectively, at EDD 11, EDD 13 and EDD16 chicken embryos xenografted with HT29 cells. Activation of PBMCs was evaluated by IL2 and IL12 secretion quantified by ELISA. At EDD18, i.e., 9 days post-graft, in ovo anti-tumor efficacy was evaluated by tumor weight, metastatic invasion (qPCR analysis of human Alu sequence in lower CAM) and quantification of tumor-infiltrating by CD8, CD4, IFN-gamma, Perforin and TNF-alpha. RESULTS: Compared to negative control, STC-1010 vaccine induced: 1) significant increase of IL-12 and IL-2 secretion in peripheric blood during the generation of all three batches of PBMCs, confirming previous results (IL-12: +52%, p=0.0003 ; IL-2: +482%, p=0.0033); 2) a significant expression of IFN-gamma in tumor (+130,83%, p=0.0185); 3) a tendency to increase infiltrating cells: CD4+: +79,2%, CD8+: +29,4% , Perforin: +105,5%, TNFα : +78,63% confirmed by immunohistochemistry and translated into 4) a significant increase of tumor necrosis (p = 0.0267); and 5) a tendency of metastasis regression (-49%); with 6) no embryonic toxicity/mortality (daily evaluation of embryonic viability) induced by STC-1010. CONCLUSION: This in ovo study confirms efficacy of the STC-1010 observed in previous CRC syngeneic models and gives more insight about STC mechanism of action with the activation and maturation of dendritic cells, induction of CD8+ and LTh1 against tumor as the main driver of the response, all without toxicity. Inovotion’s CAM model could be used for indication screening and as a pre-proof-of-concept before syngeneic model study. Citation Format: Yan Wang, Arnaud Peyronnier, Benoit Pinteur, Lionel Chalus, Corinne Tortorelli, Paul Bravetti, Jean Viallet, François Ghiringhelli, Philippe Fornies. Inovative in vivo (in ovo) CAM model to predict efficacy and mode of action of a new antitumor vaccine stc-1010 on human colorectal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6791.

Abstract 1198: T cell receptor (TCR) landscape of childhood brain tumors

Abstract T lymphocytes have a unique ability to recognize a vast array of antigens prompt by an enormous T cell receptor (TCR) repertoire. Characterization of tumor-infiltrating T cells (TILs) is key to understand MHC-restricted anti-tumor immunity and for developing T cell-centered immunotherapies such as adoptive cell therapy and tumor vaccines. In the current work, we investigated RNA-Seq data from 997 pediatric brain tumor patients and performed a large-scale comprehensive examination of the immunogenomic and TCR landscape of TILs across the entire spectrum of pediatric brain tumors. We show that the relative ratio between T cell clonal diversity and T cell abundance within each sample, represented by the clonal expansion index (CEI), is a strong predictor of prognosis both within and between tumor types. Interestingly, we show that CEI is strongly associated with molecular subgroups of medulloblastoma but not with known genomic features of these subgroups. Investigation of TCR clonotypes recognizing a common recurrent tumor-antigen across patients based on CDR3 homology and characteristics, reveals 9 TCR clusters which are tumor-type restricted with defined prognoses and HLA dominance. Using computational immunogenomics and machine learning-based investigations of these clusters we identified novel putative HLA-restricted tumor antigens which could bind and activate the clusters’ specific TCRs. Importantly, our framework grounded the foundations for developing a precision medicine approach of T cell-centered immunotherapies. These findings have major implications for understanding the interplay between T cell and tumor genomics, and for developing new immunotherapies for children with brain tumors and other cancers. Citation Format: Itay Raphael, Michal Nisnboym, Rebecca A. Raphael, Shikhar Uttam, Ian F. Pollack, Maria Chikina, Dhivyaa Rajasundaram, Gary Kohanbash. T cell receptor (TCR) landscape of childhood brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1198.

Abstract 691: Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma

Abstract Despite numerous therapeutic advances in cancers, the treatment of glioblastoma multiforme (GBM) remains a challenge. Boosting T-lymphocyte mediated responses against GBM offers a promising approach towards solving this problem. Herein, we present a therapeutic vaccination strategy that promotes the phagocytosis of tumor cells, enhances tumor antigen presentation, and induces a tumor-specific adaptive immune response with subsequent tumor eradication. This strategy consists of subcutaneous injection of irradiated whole tumor cells (rWTC) pulsed with phagocytic agonists (Mannan-BAM), TLR ligands (LTA, Poly (I:C), and R-848), and anti-CD40 agonistic antibody (collectively abbreviated as rWTC-MBTA). We evaluated the therapeutic efficacy of rWTC-MBTA strategy in mouse syngeneic GBM tumor models with GL261 and SB28 cells. In GL261 GBM model, complete regression (CR) of intracranial tumors was achieved in 70% (7/10) of rWTC-MBTA treated animals while none survived in the control group. Of note, the therapeutic efficacy of rWTC-MBTA was abolished in CD4-T and/or CD8-T lymphocyte depleted mice. Immunophenotyping analyses of peripheral lymph nodes and brain tumors of rWTC-MBTA treated mice demonstrated increased antigen presenting cells (dendritic cells and MHC II+ monocytes) and increased cytotoxic IFNγ, TNFα, and granzyme B-secreting CD4-T and CD8-T cells. All three CR mice that were rechallenged with GL261 cells intracranially 14 months after their last rWTC-MBTA treatment resisted tumor development, confirming the establishment of long-term immunological memory. In SB28 GBM model, 80% (8/10) rWTC-MBTA treated mice survived past 95 days after tumor cell implantation without any GBM-related symptoms, with median survival being only 35 days in control groups. In summary, our study demonstrated that rWTC-MBTA strategy can induce potent adaptive immune response against GBM in pre-clinical models. Citation Format: Herui Wang, Rogelio Medina, Juan Ye, Samik Chakraborty, Ondrej Uher, Mitchell Sun, Jan Zenka, Mark R. Gilbert, Karel Pacak, Zhengping Zhuang. Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 691.

Abstract 962: Oncodrivers expression analysis in primary tumors: potential for development of targeted immunotherapies for triple negative breast cancer (TNBC)

Abstract Background and significance: Lack of targets, aggressive course, resistance to treatment and poor prognosis are typical characteristics of TNBC. Like other breast cancer (BC) types, TNBC cells are also dependent on oncodrivers that potentiate the malignancy by inducing proliferation. This dependency makes oncodrivers the target of choice for new BC therapies. Here, we focus on cellular distribution of HER3, EGFR, and MET in TNBC tumors. Analysis of oncodrivers expression along with immune cell landscape in TNBC tumors pre- and post-chemotherapy will help in understanding the interaction between immune response and oncodrivers status and how that correlates with therapeutic response(s) in patients to design future clinical trial using targeted immunotherapy.Methods: In an IRB-approved study, immunohistochemistry was performed using tissue microarray (TMA) on surgical blocks from a cohort of 90 TNBC patients. Two separate multiplex panels: (1) Oncodrivers (HER3, EGFR & MET); (2) Immune cells (CD4, CD8, CD20, CD56, CD45, & PD1) were used. Subsequently, oncodrivers expression was correlated to immune infiltration, clinical responses, and survival by reviewing the pathological data. Results: We analyzed total 208 QC-passed TMA cores. Irrespective of clinical outcome, EGFR (41.13% vs 15.09%, p<0.0001) and MET (35.67% vs 11.61%, p<0.0001) showed increase in the number of positive cells in tumor as compared to benign tissue. Curiously, limited expression of HER3 was significantly lower in stromal tissue (1.62% vs 0.59%, p=0.026). The distribution of MET and EGFR showed a significant correlation (r=0.32, p<0.0001) whereas HER3 expression was mutually exclusive to either MET (r=-0.006, p=0.931) or EGFR (r=-0.07, p=0.291). Analysis of clinical and pathological data demonstrated that HER3 expression was higher in patients treated with neoadjuvant chemotherapy (2.95% versus 0.79%, p=0.004). There was higher expression of HER3 in node positive disease (p=0.013) and MET in node negative disease (p=0.004). There was no change in expression between pre- and post-chemotherapy samples for MET (p=0.097) and EGFR (p=0.754). Interestingly, the intermediate strength of EGFR expression was significantly associated with favorable overall survival in patients treated with neoadjuvant chemotherapy (univariate Cox model, N=13, HR=0.28, p=0.024). Analysis of immune infiltrate showed a significant correlation between CD45 and EGFR (r=0.379, p<0.001) as well as MET (r=0.443, p<0.001). Conclusion: EGFR and MET overexpressed in tumor tissue of TNBC specimens while smaller proportion of HER3+ cells were limited to tumor as compared to stroma. HER3 appears to be altered by neoadjuvant chemotherapy. EGFR and MET expression correlated with CD45+ immune cells. To this end, HER3, EGFR, and MET remain viable options as potential targets for dendritic cell tumor vaccines. Citation Format: Saurabh K. Garg, Nicholas T. Champion, Amrita Basu, Junmin Whiting, Weihong Sun, Susan Hoover, Brian J. Czerniecki. Oncodrivers expression analysis in primary tumors: potential for development of targeted immunotherapies for triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 962.

Up-regulation of Core 1 Beta 1, 3-Galactosyltransferase Suppresses Osteosarcoma Growth with Induction of IFN-γ Secretion and Proliferation of CD8+ T Cells.

Abnormal glycosylation often occurs in tumor cells. T-synthase (core 1 beta 1,3- galactosyltransferase, C1GALT1, or T-synthase) is a key enzyme involved in O-glycosylation. Although T-synthase is known to be important in human tumors, the effects of T-synthase and T-antigen on human tumor responses remain poorly defined. In this study, a T-synthase-specific short hairpin RNA (shRNA) or T-synthase-specific eukaryotic expression vector(pcDNA3.1(+)) was transfected into murine Osteosarcoma LM8 cells to assess the effects of T-synthase on T cells and cytokines. The up-regulation of T-synthase promoted the proliferation of osteosarcoma cells in vitro, but it promoted the proliferation of tumor initially up to 2-3 weeks but showed significant growth inhibitory effect after 3 weeks post-implantation in vivo. Osteosarcoma cells with high T-synthase expression in vitro promoted the proliferation and inhibited the apoptosis of CD8+ T cells. Further, T-synthase upregulation promoted CD8+ T-cell proliferation and the increased production of CD4+ T cell-derived IFN-γ cytokines to induce the increased tumor lethality of CTLs. Our data suggest that high T-synthase expression inhibits tumor growth by improving the body's anti-tumor immunity. Therefore, using this characteristic to prepare tumor cell vaccines with high immunogenicity provides a new idea for clinical immunotherapy of osteosarcoma.

Immunotherapy for advanced or recurrent hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is associated with high morbidity and mortality, and is prone to intra- and extrahepatic metastasis due to the anatomical and functional characteristics of the liver. Due to the complexity and high relapse rate associated with radical surgery or radiofrequency ablation, immune checkpoint inhibitors (ICIs) are increasingly being used to treat HCC. Several immunotherapeutic agents, along with their combinations, have been clinically approved to treat advanced or recurrent HCC. This review discusses the leading ICIs in practice and those currently undergoing randomized phase 1-3 trials as monotherapy or combination therapy. Furthermore, we summarize the rapidly developing alternative strategies such as chimeric antigen receptor-engineered T cell therapy and tumor vaccines. Combination therapy is a promising potential treatment option. These immunotherapies are also summarized in this review, which provides insights into the advantages, limitations, and novel angles for future research in establishing viable and alternative therapies against HCC.

Tumor cell vaccine combined with Newcastle disease virus promote immunotherapy of lung cancer.

Lung cancer is a fatal disease with the highest worldwide morbidity and mortality rates. Despite recent advances in targeted therapy and immune checkpoint inhibitors for cancer, their efficacy remained limited. Therefore, we designed a Newcastle disease virus (NDV)-modified tumor whole-cell vaccine as a therapeutic vaccine and identified its antigen presentation level to develop effective immunotherapy. Then, we calculated the therapeutic and immune-stimulating effects of NDV-modified lung cancer cell vaccine and intratumoral NDV injection combination on tumor-bearing mice. The results showed that the immunogenic cell death (ICD) expression in NDV-modified lung cancer cell vaccine stimulates dendritic cell maturation and T cell activation in vivo and in vitro. Moreover, NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could significantly inhibit tumor growth and enhance the differentiation of Th1 cells and Inflammatory cell infiltration in vivo, leading to an excellent immunotherapeutic effect. Therefore, our results revealed that NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could promote antigen presentation and induce a strong antitumor immune response, which provided a promising combined therapy strategy for tumor immunotherapy.

Catalytic immunotherapy-photothermal therapy combination for melanoma by ferroptosis-activating vaccine based on artificial nanoenzyme

Tumor cell vaccine is a promising approach for cancer therapy to activate tumor immune, which can be achieved by tumor cells immunogenic cell death (ICD), converting in situ tumors into endogenous vaccination strategy, and ferroptosis has been proved to induce ICD occurrence. Ferroptosis is triggered by artificial nanoenzyme copper telluride mimicking peroxidase and glutathione oxidase, based on which the ferroptosis-activating vaccine (termed as CM CTNPs@OVA) was designed and established for catalytic immunotherapy. Owing to photothermal effect of copper telluride, photothermal therapy (PTT) was combined for an intensive cancer therapeutic effect. CM CTNPs@OVA was composed of solid mesoporous copper telluride nanoparticles, ovalbumin (OVA) loaded in mesoporous, and melanoma cell membrane coating surface. In in vitro and in vivo investigations, CM CTNPs@OVA, with particle size of 113.7 ± 1.7 nm, was certified to release copper ions for ferroptosis initiation, and OVA directly maturated dendritic cell (DC) as exogenous antigens extracellularly. ICD was then induced by ferroptosis pathway and PTT to release damage-associated molecular patterns for DC maturation and subsequent T cells recruitment. CM CTNPs@OVA-treated melanoma with exited inhibition rate, proving that the strategy of catalytic immunotherapy-PTT combination by ferroptosis-activating vaccine possessed massive potential for melanoma therapy based on nanoenzyme copper telluride.

A single-cell surgery microfluidic device for transplanting tumor cytoplasm into dendritic cells without nuclei mixing.

This study aimed to demonstrate the feasibility of generating tumor cell vaccine models by single-cell surgery in a microfluidic device that integrates one-to-one electrofusion, shear flow reseparation, and on-device culture. The device was microfabricated from polydimethylsiloxane (PDMS) and consisted of microorifices (aperture size: ∼3μm) for one-to-one fusion, and microcages for on-device culture. Using the device, we could achieve one-to-one electrofusion of leukemic plasmacytoid dendritic cells (DC-like cells) and Jurkat cells with a fusion efficiency of ∼ 80%. Fusion via the narrow microorifices allowed DC-like cells to acquire cytoplasmic contents of the Jurkat cells while preventing nuclei mixing. After fusion, the DC-like cells were selectively reseparated from the Jurkat cells by shear flow application to generate tumor nuclei-free antigen-recipient DC-like (tarDC-like) cells. When cultured as single cells on the device, these cells could survive under gentle medium perfusion with a median survival time of 11.5h, although a few cells could survive longer than 36h. Overall, this study demonstrates single-cell surgery in a microfluidic device for potential generation of dendritic cell vaccines which are uncontaminated with tumor nucleic materials. We believe that this study will inspire the generation of safer tumor cell vaccines for cancer immunotherapy.

Whole-cell tumor vaccines desialylated to uncover tumor antigenic Gal/GalNAc epitopes elicit anti-tumor immunity

BackgroundAberrant sialoglycans on the surface of tumor cells shield potential tumor antigen epitopes, escape recognition, and suppress activation of immunocytes. α2,3/α2,6Gal- and α2,6GalNAc (Gal/GalNAc)-linked sialic acid residues of sialoglycans could affect macrophage galactose-type lectins (MGL) mediated-antigen uptake and presentation and promote sialic acid-binding immunoglobulin-like lectins (Siglecs) mediated-immunosuppression. Desialylating sialoglycans on tumor cells could present tumor antigens with Gal/GalNAc residues and overcome glyco-immune checkpoints. Thus, we explored whether vaccination with desialylated whole-cell tumor vaccines (DWCTVs) triggers anti-tumor immunity in ovarian cancer (OC).MethodsSialic acid (Sia) and Gal/GalNAc residues on OC A2780, OVCAR3, and ID8 cells treated with α2-3 neuraminidase (α2-3NA) and α2-6NA, and Sigec-9 or Siglec-E and MGL on DCs pulsed with desialylated OC cells were identified using flow cytometry (FCM); RT-qPCR determined IFNG expression of T cells, TRBV was sequenced using Sanger sequencing and cytotoxicity of αβ T cells was measured with LDH assay; Anti-tumor immunity in vivo was validated via vaccination with desialylated whole-cell ID8 vaccine (ID8 DWCTVs).ResultsGal/GalNAc but not Sia residues were significantly increased in the desialylated OC cells. α2-3NA-modified DWCTV increased MGL but decreased Siglec-9 or Siglec E expression on DCs. MGLbright/Siglec-9dim DCs significantly up-regulated IFNG expression and CD4/CD8 ratio of T cells and diversified the TCR repertoire of αβ T-cells that showed enhanced cytotoxic activity. Vaccination with α2-3NA-modified ID8 DWCTVs increased MGLbright/Siglec-Edim DCs in draining lymph nodes, limited tumor growth, and extended survival in tumor-challenged mice.ConclusionDesialylated tumor cell vaccine could promote anti-tumor immunity and provide a strategy for OC immunotherapy in a clinical setting.

EBAG9 controls CD8+ T cell memory formation responding to tumor challenge in mice.

Insight into processes that determine CD8+ T cell memory formation has been obtained from infection models. These models are biased toward an inflammatory milieu and often use high-avidity CD8+ T cells in adoptive-transfer procedures. It is unclear whether these conditions mimic the differentiation processes of an endogenous repertoire that proceed upon noninflammatory conditions prevailing in premalignant tumor lesions. We examined the role of cytolytic capacity on CD8+ T cell fate decisions when primed by tumor cells or by minor histocompatibility antigen–mismatched leukocytes. CD8+ memory commitment was analyzed in Ebag9-deficient mice that exhibited enhanced tumor cell lysis. This property endowed Ebag9–/– mice with extended control of Tcl-1 oncogene–induced chronic lymphocytic leukemia progression. In Ebag9–/– mice, an expanded memory population was obtained for anti-HY and anti–SV-40 T antigen–specific T cells, despite unchanged effector frequencies in the primary response. By comparing the single-cell transcriptomes of CD8+ T cells responding to tumor cell vaccination, we found differential distribution of subpopulations between Ebag9+/+ and Ebag9–/– T cells. In Ebag9–/– cells, these larger clusters contained genes encoding transcription factors regulating memory cell differentiation and anti-apoptotic gene functions. Our findings link EBAG9-controlled cytolytic activity and the commitment to the CD8+ memory lineage.

IMMU-06. Landscape of adaptive immunity of childhood brain cancers

T lymphocytes have a unique ability to recognize a vast array of antigens prompted by an enormous T cell receptor (TCR) repertoire. Characterization of tumor-infiltrating T cells (TILs) is key to understand MHC-restricted anti-tumor immunity and for developing T cell-centered immunotherapies such as adoptive cell therapy and tumor vaccines. In the current work, we investigated RNA-Seq data from 997 pediatric brain tumor patients and performed a large-scale comprehensive examination of the immunogenomic and TCR landscape of TILs across the entire spectrum of pediatric brain tumors. We show that the relative ratio between T cell diversity (clonality) and T cell abundance within each sample, represented by the clonal expansion index (CEI), is a strong predictor of prognosis both within and between tumor types. Interestingly, we show that CEI was strongly associated with molecular subgroups of medulloblastoma but not with known tumor-genomic features of these subgroups. Investigation of TCR clones recognizing a common recurrent tumor-antigen across patients based on CDR3 homology and characteristics, reveals 9 TCR clusters which are tumor type restricted with defined prognoses and HLA dominance. Using computational immunogenomics and machine learning-based investigations of these clusters yielded novel putative HLA-restricted tumor antigens which could bind and activate the clusters’ specific TCRs. Importantly, our framework grounded the foundations for developing a precision medicine approach of T cell-centered immunotherapies. These findings have major implications for understanding the interplay between T cell and tumor genomic, and for developing new immunotherapies for children with brain tumors.

Invariant NKT cell-augmented GM-CSF-secreting tumor vaccine is effective in advanced prostate cancer model.

Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenicSV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenicTRAMP mice were then castrated at ~ 20weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation.

Bifunctional Fusion Membrane‐Based Hydrogel Enhances Antitumor Potency of Autologous Cancer Vaccines by Activating Dendritic Cells

AbstractAutologous tumor cell vaccine is an individualized tumor treatment strategy to elicit tumor‐specific immune responses. However, it is difficult to exert efficacy in “cold” tumors, which lack tumor‐infiltrating T cells and are not sensitive to immunotherapy. Here, a dendritic cells (DCs) activation hydrogel is constructed based on bifunctional fusion membrane nanoparticles (FM‐NPs) composed of autologous tumor cell membranes and Mycobacterium phlei membrane extracts. The FM‐NPs not only provide tumor antigens but also can activate DCs. Afterward, the FM‐NPs are loaded in an injectable alginate hydrogel together with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). GM‐CSF releases rapidly and recruits DCs to hydrogel, while FM‐NPs retain in hydrogel to continuously interconnected with DCs, enriching mature DCs loaded with tumor antigens. In the 4T1 mouse breast tumor model, this hydrogel promotes the maturation of DCs in tumor‐draining lymph nodes and induces sufficient effector memory T cells that migrate to the tumor microenvironment. This successfully converts the “cold” tumors to “hot”, thus exerting a significant antitumor effect synergized with the PD‐1 antibody. It is also verified the inhibitory effect of FM‐NPs using human gastric cancer organoids. Altogether, these findings demonstrate the application potential for the bifunctional fusion membrane‐based hydrogel as an autologous tumor vaccine by activating DCs.