Combined Tumor Cell-Based Vaccination and Interleukin-12 Gene Therapy Polarizes the Tumor Microenvironment in Mice

Melittin-incorporated nanomedicines for enhanced cancer immunotherapy

Immunotherapy is a rapidly developing and effective strategy for cancer therapy. Among various immunotherapy approaches, peptides have garnered significant attention due to their potent immunomodulatory effects. In particular, melittin emerged as a promising candidate to enhance cancer immunotherapy by inducing immunogenic cell death, promoting the maturation of antigen-presenting cells, activating T cells, enhancing the infiltration and cytotoxicity of effector lymphocytes, and modulating macrophage phenotypes for relieving immunosuppression. However, the clinical application of melittin is limited by poor targeting and systemic toxicity. To overcome these challenges, melittin has been incorporated into biomaterials and related nanotechnologies, resulting in extended circulation time in vivo, improved targeting, reduced adverse effects, and enhanced anti-cancer immunological action. This review provides an in-depth analysis of the immunomodulatory effects of melittin-incorporated nanomedicines and examines their development and challenges for clinical cancer immunotherapy.

Therapeutic Adenovirus Vaccine Combined Immunization with IL-12 Induces Potent CD8+ T Cell Anti-Tumor Immunity in Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma is a kind of tumor with a high malignant degree and mortality rate, and there is no effective treatment method. Currently, immunotherapy has shown good prospects in treating hepatocellular carcinoma. As an important approach of immunotherapy, the vaccine has become an attractive method for tumor treatment. This study developed an adenovirus vaccine containing tumor antigen glypican-3 and adjuvant interleukin 12. The subcutaneous tumor model was intramuscularly immunized three times with vaccines at a ten-day interval. Compared with the control group, the proliferation of CD 8⁺ T cell, the induction of multifunctional CD 8⁺ T cell and dendritic cells, and cytotoxic T lymphocyte activity were significantly increased in the combined immunization group, and the growth of tumor was inhibited obviously. The therapeutic effect of the vaccine of glypican-3 and interleukin 12 mainly depends on the anti-tumor effect of CD 8⁺ T cells mediated by dendritic cells. Likewise, this vaccine also showed a good therapeutic effect in the lung metastasis model of hepatocellular carcinoma. Therefore, the adenovirus vaccine of glypican-3 and interleukin 12 might become a potential way to treat hepatocellular carcinoma.

Abstract

Hepatocellular carcinoma (HCC) is one of the cancers with the highest morbidity and mortality in the world. However, clinical progress in the treatment of HCC has not shown a satisfactory therapeutic effect. Here, we have developed a novel strategy to treat HCC with an adenovirus (Ad)-based vaccine, which contains a specific antigen glypican-3 (GPC3) and an immunostimulatory cytokine IL-12. In the subcutaneous tumor model, Ad-IL-12/GPC3 vaccine was injected into muscles three times to evaluate its therapeutic effect. Compared with the control immunization group, the Ad-IL-12/GPC3 immunization group showed a significant tumor growth inhibition effect, which was confirmed by the reduced tumor volume and the increased tumor inhibition. Ad-IL-12/GPC3 co-immunization promoted the induction and maturation of CD11c⁺ or CD8⁺CD11c⁺ DCs and increased the number of tumor-infiltrating CD8⁺ T cells. Furthermore, in the Ad-IL-12/GPC3 group, the proliferation of CD8⁺ T cells, the induction of multifunctional CD8⁺ T cells, and CTL activity were significantly increased. Interestingly, the deletion of CD8⁺ T cells abolished tumor growth inhibition by Ad-IL-12/GPC3 treatment, suggesting that CD8⁺ T cell immune responses were required to eliminate the tumor. Likewise, Ad-IL-12/GPC3 vaccine also effectively inhibited lung tumor growth or metastasis by enhancing CD8⁺ DCs-mediated multifunctional CD8⁺ T cell immune responses in the lung metastasis model. Therefore, these results indicate that IL-12 combined with Ad-GPC3 vaccine co-immunization might provide a promising therapeutic strategy for HCC patients.

Mesenchymal stromal cells as carriers of IL-12 reduce primary and metastatic tumors of murine melanoma

Due to immunosuppressive properties and confirmed tropism towards cancer cells mesenchymal stromal cells (MSC) have been used in many trials. In our study we used these cells as carriers of IL-12 in the treatment of mice with primary and metastatic B16-F10 melanomas. IL-12 has confirmed anti-cancer activity, induces a strong immune response against cancer cells and acts as an anti-angiogenic agent. A major limitation of the use of IL-12 in therapy is its systemic toxicity. The aim of the work was to develop a system in which cytokine may be administered intravenously without toxic side effects. In this study MSC were used as carriers of the IL-12. We confirmed antitumor effectiveness of the cells secreting IL-12 (MSC/IL-12) in primary and metastatic murine melanoma models. We observed inhibition of tumor growth and a significant reduction in the number of metastases in mice after MSC/IL-12 administration. MSC/IL-12 decreased vascular density and increased the number of anticancer M1 macrophages and CD8⁺ cytotoxic T lymphocytes in tumors of treated mice. To summarize, we showed that MSC are an effective, safe carrier of IL-12 cytokine. Administered systemically they exert therapeutic properties of IL-12 cytokine without toxicity. Therapeutic effect may be a result of pleiotropic (proinflammatory and anti-angiogenic) properties of IL-12 released by modified MSC.

Brachytherapy in a Single Dose of 10Gy as an "in situ" Vaccination

Radiotherapy (RT) is one of the major methods of cancer treatment. RT destroys cancer cells, but also affects the tumor microenvironment (TME). The delicate balance between immunomodulation processes in TME is dependent, among other things, on a specific radiation dose. Despite many studies, the optimal dose has not been clearly determined. Here, we demonstrate that brachytherapy (contact radiotherapy) inhibits melanoma tumor growth in a dose-dependent manner. Doses of 10Gy and 15Gy cause the most effective tumor growth inhibition compared to the control group. Brachytherapy, at a single dose of ≥ 5Gy, resulted in reduced tumor blood vessel density. Only a dose of 10Gy had the greatest impact on changes in the levels of tumor-infiltrating immune cells. It most effectively reduced the accumulation of protumorogenic M2 tumor-associated macrophages and increased the infiltration of cytotoxic CD8⁺ T lymphocytes. To summarize, more knowledge about the effects of irradiation doses in anticancer therapy is needed. It may help in the optimization of RT treatment. Our results indicate that a single dose of 10Gy leads to the development of a robust immune response. It seems that it is able to convert a tumor microenvironment into an “in situ” vaccine and lead to a significant inhibition of tumor growth.

Development of Tumor Cell-Based Vaccine with IL-12 Gene Electrotransfer as Adjuvant

Tumor cell-based vaccines use tumor cells as a source of tumor-associated antigens. In our study, we aimed to develop and test a tumor vaccine composed of tumor cells killed by irradiation combined with in vivo interleukin-12 gene electrotransfer as an adjuvant. Vaccination was performed in the skin of B16-F10 malignant melanoma or CT26 colorectal carcinoma tumor-bearing mice, distant from the tumor site and combined with concurrent tumor irradiation. Vaccination was also performed before tumor inoculation in both tumor models and tumor outgrowth was followed. The antitumor efficacy of vaccination in combination with tumor irradiation or preventative vaccination varied between the tumor models. A synergistic effect between vaccination and irradiation was observed in the B16-F10, but not in the CT26 tumor model. In contrast, up to 56% of mice were protected from tumor outgrowth in the CT26 tumor model and none were protected in the B16-F10 tumor model. The results suggest a greater contribution of the therapeutic vaccination to tumor irradiation in a less immunogenic B16-F10 tumor model, in contrast to preventative vaccination, which has shown greater efficacy in a more immunogenic CT26 tumor model. Upon further optimization of the vaccination and irradiation regimen, our vaccine could present an alternative tumor cell-based vaccine.

Combination of anti-vascular agent - DMXAA and HIF-1α inhibitor - digoxin inhibits the growth of melanoma tumors

Vascular disrupting agents as DMXAA inhibit tumor growth only for a short period of time followed by rapid tumor regrowth. Among others, hypoxia and presence of transcription factor HIF-1α are responsible for tumors regrowth. The aim of our study was to investigate the inhibition of murine melanoma growth by combining two agents: anti-vascular - DMXAA and the HIF-1α inhibitor - digoxin and explaining the mechanism of action of this combination. After DMXAA treatment tumor size was reduced only for a limited time. After 7 days regrowth of tumors was observed and number of vessels was increased especially in tumor's peripheral areas. DMXAA also induced an influx of immune cells: macrophages, CD8+ cytotoxic lymphocytes, NK cells, CD4+ lymphocytes. Administration of digoxin alone inhibited the growth of tumors. Administration of both agents in the proper sequence significantly inhibited the regrowth of tumors better than either agents alone. Combination therapy reduced number of newly formed vessels. In tumors of mice treated with combination therapy, the number of macrophages M1, CD8+ cytotoxic lymphocytes, NK cells and to a lesser extent CD4+ cells was increased. The combination of anti-vascular agents with HIF-1α inhibitors appears to be an effective therapeutic option.

M1-like macrophages change tumor blood vessels and microenvironment in murine melanoma

Tumor-associated macrophages (TAMs) play a significant role in at least two key processes underlying neoplastic progression: angiogenesis and immune surveillance. TAMs phenotypic changes play important role in tumor vessel abnormalization/ normalization. M2-like TAMs stimulate immunosuppression and formation of defective tumor blood vessels leading to tumor progression. In contrast M1-like TAMs trigger immune response and normalize irregular tumor vascular network which should sensitize cancer cells to chemo- and radiotherapy and lead to tumor growth regression. Here, we demonstrated that combination of endoglin-based DNA vaccine with interleukin 12 repolarizes TAMs from tumor growth-promoting M2-like phenotype to tumor growth-inhibiting M1-like phenotype. Combined therapy enhances tumor infiltration by CD4⁺, CD8⁺ lymphocytes and NK cells. Depletion of TAMs as well as CD8⁺ lymphocytes and NK cells, but not CD4⁺ lymphocytes, reduces the effect of combined therapy. Furthermore, combined therapy improves tumor vessel maturation, perfusion and reduces hypoxia. It caused that suboptimal doses of doxorubicin reduced the growth of tumors in mice treated with combined therapy. To summarize, combination of antiangiogenic drug and immunostimulatory agent repolarizes TAMs phenotype from M2-like (pro-tumor) into M1-like (anti-tumor) which affects the structure of tumor blood vessels, improves the effect of chemotherapy and leads to tumor growth regression.

Study of recombinant human interleukin-12 for treatment of complications after radiotherapy for tumor patients

AIM

To evaluate the treatment effects of recombinant human interleukin-12 (rhIL-12) on radiotherapy complications, such as severe myelosuppression or pancytopenia, the decline or imbalance of immune function, etc.

METHODS

The patients received high-dose and short-course precise radiotherapy, such as Cyber knife and image-guided radiotherapy (IGRT), which can cause myelosuppression or pancytopenia and immune function decline within a short time. One-hundred subjects were enrolled in the study, and 50 were randomized to a treatment group which used rhIL-12 and 50 were randomized to a control group which used symptomatic and supportive therapy after radiotherapy. The 50 subjects in the treatment group were further divided into five subgroups and intervened with rhIL-12 at a dose of 50, 100, 150, 200 or 250 ng/kg respectively. The dose-effect relationship was observed.

RESULTS

RhIL-12 significantly attenuated the decrease of peripheral blood cells in the treatment group, and immune function was improved after treatment. Due to the different radiation doses, there was a fluctuation within 12 h after treatment but mostly showing an increasing trend. As to the clinical manifestations, 2 patients in the 250 ng/kg subgroup showed low fever after administration, 1 patient in the 200 ng/kg subgroup and 2 patients in the 250 ng/kg subgroup showed mild impairment of liver function during the observation period.

CONCLUSION

RhIL-12 has effective therapeutic and protective effects on complications following radiotherapy, such as the decline of blood cells, myelosuppression and the decline or imbalance of immune function, which indicated good prospects for development and application.

Global Regulatory T-Cell Research from 2000 to 2015: A Bibliometric Analysis

We aimed to analyze the global scientific output of regulatory T-cell (Treg) research and built a model to qualitatively and quantitatively evaluate publications from 2000 to 2015. Data were obtained from the Web of Science Core Collection (WoSCC) of Thomson Reuters on January 1, 2016. The bibliometric method and Citespace III were used to analyze authors, journals, publication outputs, institutions, countries, research areas, research hotspots, and trends. In total, we identified 35,741 publications on Treg research from 2000 to 2015, and observed that the annual publication rate increased with time. The Journal of Immunology published the highest number of articles, the leading country was the USA, and the leading institute was Harvard University. Sakaguchi, Hori, Fontenot, and Wang were the top authors in Treg research. Immunology accounted for the highest number of publications, followed by oncology, experimental medicine, cell biology, and hematology. Keyword analysis indicated that autoimmunity, inflammation, cytokine, gene expression, foxp3, and immunotherapy were the research hotspots, whereas autoimmune inflammation, gene therapy, granzyme B, RORγt, and th17 were the frontiers of Treg research. This bibliometric analysis revealed that Treg-related studies are still research hotspots, and that Treg-related clinical therapies are the research frontiers; however, further study and collaborations are needed worldwide. Overall, our findings provide valuable information for the editors of immunology journals to identify new perspectives and shape future research directions.

Personalized cell-mediated immunotherapy and vaccination: combating detrimental uprisings of malignancies

A large number of researchers worldwide have conducted various investigations to advance the cell-based immunotherapies and to examine their clinical benefits as an ultimate prevention and/or treatment modalities against life-threatening malignancies. This dominion needs integration of science and technology to change the face of treatment of diseases towards much more personalized medicines. It is now plausible to reprogram the human cells for the prevention and treatment of diseases through various mechanisms such as modulation of immune system, nonetheless we should understand the complexity of biological functions of the cells in a holistic way to be able to manipulate the central dogma of the life to prevent any inadvertent mistake. We should, if not must, comprehend the interrelations of the cellular components (e.g., transport machineries) in the developmental processes of diseases. Still, we do not have a complete image of life, perhaps as expressive barcodes, and many pieces are missing. While completing this puzzle to picture the whole image and examine new treatment modalities, we should take extra caution upon unknown/little-known biological phenomena because trifling modulation/ alteration in the complex systems of the life may result in tremendous impacts. In short, it seems we need to consider malignancies as complex systems and treat them in a holistic manner by targeting its hallmarks. Taken all, the immune system reinforcement would be one of the main foundations in combating detrimental malignancy uprising.