Autologous tumor cell vaccines for post-operative active-specific immunotherapy of colorectal carcinoma: long-term patient survival and mechanism of function

Individualized Multimodal Immunotherapy (IMI): Scientific Rationale and Clinical Experience from a Single Institution

Oncolytic viruses and combinatorial immunotherapy for cancer (this Special Issue) are both part of cancer treatment at IOZK. This review focusses on an individual multimodal cancer immunotherapy concept developed by IOZK, Cologne, Germany. The scientific rationale for employing three main components is explained: (i) oncolytic Newcastle disease virus, (ii) modulated electrohyperthermia and (iii) individual tumor antigen and oncolytic virus modified dendritic cell vaccine (IO-VACR). The strategy involves repeated cancer-immunity cycles evoked in cancer patients by systemic oncolytic virus exposure plus hyperthermia pretreatment to induce immunogenic cell death followed by intradermal IO-VACR vaccination. As an example of the experience at IOZK, we present the latest results from combining the immunotherapy with standard treatment of patients suffering from glioblastoma multiforme. The promising clinical results in terms of overall survival benefit of additional individualized multimodal immunotherapy are presented. The cancer-immunity cycle, as introduced 10 years ago, describes key important steps occurring locally at the sites of both tumor and draining lymph nodes. This view is extended here towards systemic events occuring in blood where immunogenic cell death-induced tumor antigens are transported into the bone marrow. For 20 years it has been known that bone marrow is an antigen-responsive organ in which dendritic cells present tumor antigens to T cells leading to immunological synapse formation, tumor antigen-specific T cell activation and memory T cell formation. Bone marrow is known to be the most prominent source of de novo cellular generation in the body and to play an important role for the storage and maintenance of immunological memory. Its systemic activation is recommended to augment cancer-immunity cycles.

Developing Oncolytic Viruses for the Treatment of Cervical Cancer

Cervical cancer represents one of the most important malignancies among women worldwide. Current therapeutic approaches for cervical cancer are reported not only to be inadequate for metastatic cervical cancer, but are also considered as cytotoxic for several patients leading to serious side effects, which can have negative implications on the quality of life of women. Therefore, there is an urgent need for the development of innovative and effective treatment options. Oncolytic viruses can eventually become effective biological agents, since they preferentially infect and kill cancer cells, while leaving the normal tissue unaffected. Moreover, they are also able to leverage the host immune system response to limit tumor growth. This review aims to systematically describe and discuss the different types of oncolytic viruses generated for targeting cervical cancer cells, as well as the outcome of the combination of virotherapy with conventional therapies. Although many preclinical studies have evaluated the therapeutic efficacy of oncolytic viruses in cervical cancer, the number of clinical trials so far is limited, while their oncolytic properties are currently being tested in clinical trials for the treatment of other malignancies.

Bifunctional cancer cell-based vaccine concomitantly drives direct tumor killing and antitumor immunity

The administration of inactivated tumor cells is known to induce a potent antitumor immune response; however, the efficacy of such an approach is limited by its inability to kill tumor cells before inducing the immune responses. Unlike inactivated tumor cells, living tumor cells have the ability to track and target tumors. Here, we developed a bifunctional whole cancer cell-based therapeutic with direct tumor killing and immunostimulatory roles. We repurposed the tumor cells from interferon-β (IFN-β) sensitive to resistant using CRISPR-Cas9 by knocking out the IFN-β-specific receptor and subsequently engineered them to release immunomodulatory agents IFN-β and granulocyte-macrophage colony-stimulating factor. These engineered therapeutic tumor cells (ThTCs) eliminated established glioblastoma tumors in mice by inducing caspase-mediated cancer cell apoptosis, down-regulating cancer-associated fibroblast-expressed platelet-derived growth factor receptor β, and activating antitumor immune cell trafficking and antigen-specific T cell activation signaling. This mechanism-based efficacy of ThTCs translated into a survival benefit and long-term immunity in primary, recurrent, and metastatic cancer models in immunocompetent and humanized mice. The incorporation of a double kill-switch comprising herpes simplex virus-1 thymidine kinase and rapamycin-activated caspase 9 in ThTCs ensured the safety of our approach. Arming naturally neoantigen-rich tumor cells with bifunctional therapeutics represents a promising cell-based immunotherapy for solid tumors and establishes a road map toward clinical translation.

Counteracting Immunosuppression in the Tumor Microenvironment by Oncolytic Newcastle Disease Virus and Cellular Immunotherapy

An apparent paradox exists between the evidence for spontaneous systemic T cell- mediated anti-tumor immune responses in cancer patients, observed particularly in their bone marrow, and local tumor growth in the periphery. This phenomenon, known as "concomitant immunity" suggests that the local tumor and its tumor microenvironment (TME) prevent systemic antitumor immunity to become effective. Oncolytic Newcastle disease virus (NDV), an agent with inherent anti-neoplastic and immune stimulatory properties, is capable of breaking therapy resistance and immunosuppression. This review updates latest information about immunosuppression by the TME and discusses mechanisms of how oncolytic viruses, in particular NDV, and cellular immunotherapy can counteract the immunosuppressive effect of the TME. With regard to cellular immunotherapy, the review presents pre-clinical studies of post-operative active-specific immunotherapy and of adoptive T cell-mediated therapy in immunocompetent mice. Memory T cell (MTC) transfer in tumor challenged T cell-deficient nu/nu mice demonstrates longevity and functionality of these cells. Graft-versus-leukemia (GvL) studies in mice demonstrate complete remission of late-stage disease including metastases and cachexia. T cell based immunotherapy studies with human cells in human tumor xenotransplanted NOD/SCID mice demonstrate superiority of bone marrow-derived as compared to blood-derived MTCs. Results from clinical studies presented include vaccination studies using two different types of NDV-modified cancer vaccine and a pilot adoptive T-cell mediated therapy study using re-activated bone marrow-derived cancer-reactive MTCs. As an example for what can be expected from clinical immunotherapy against tumors with an immunosuppressive TME, results from vaccination studies are presented from the aggressive brain tumor glioblastoma multiforme. The last decades of basic research in virology, oncology and immunology can be considered as a success story. Based on discoveries of these research areas, translational research and clinical studies have changed the way of treatment of cancer by introducing and including immunotherapy.

Molecular Mechanisms of Anti-Neoplastic and Immune Stimulatory Properties of Oncolytic Newcastle Disease Virus

Oncolytic viruses represent interesting anti-cancer agents with high tumor selectivity and immune stimulatory potential. The present review provides an update of the molecular mechanisms of the anti-neoplastic and immune stimulatory properties of the avian paramyxovirus, Newcastle Disease Virus (NDV). The anti-neoplastic activities of NDV include (i) the endocytic targeting of the GTPase Rac1 in Ras-transformed human tumorigenic cells; (ii) the switch from cellular protein to viral protein synthesis and the induction of autophagy mediated by viral nucleoprotein NP; (iii) the virus replication mediated by viral RNA polymerase (large protein (L), associated with phosphoprotein (P)); (iv) the facilitation of NDV spread in tumors via the membrane budding of the virus progeny with the help of matrix protein (M) and fusion protein (F); and (v) the oncolysis via apoptosis, necroptosis, pyroptosis, or ferroptosis associated with immunogenic cell death. A special property of this oncolytic virus consists of its potential for breaking therapy resistance in human cancer cells. Eight examples of this important property are presented and explained. In healthy human cells, NDV infection activates the RIG-MAVs immune signaling pathway and establishes an anti-viral state based on a strong and uninhibited interferon α,ß response. The review also describes the molecular determinants and mechanisms of the NDV-mediated immune stimulatory effects, in which the viral hemagglutinin-neuraminidase (HN) protein plays a prominent role. The six viral proteins provide oncolytic NDV with a special profile in the treatment of cancer.

Overexpression of Nicotinamide N-methyltransferase mainly covers stroma of colorectal cancer and correlates with unfavorable survival by its product 1-MNA

Background: Accumulating evidence indicates that Nicotinamide N-methyltransferase (NNMT) is abnormally expressed in tumor tissues of several cancers including colorectal cancer (CRC) and associated with cancer progression. However, the distribution characteristics and the clinical value of each part of NNMT expression in CRC are still not fully understood. The purpose of this study is to determine the distribution of NNMT expression and its association with survival in CRC. Methods: By using the cancer genome atlas (TCGA) and clinical proteomic tumor analysis consortium (CPTAC), we firstly analyzed the difference of gene and protein levels of NNMT between CRC and normal colorectal tissue. Then, NNMT protein expressions were detected in 18 intraepithelial neoplastic samples and 177 CRC tumor samples through immunohistochemistry in our study cohort. Furthermore, the relationship between NNMT expression and clinicopathological characteristics, overall survival (OS) and disease-free survival (DFS) of CRC patients were analyzed by Pearson χ2 test and log-rank test, respectively, in public datasets and our study cohort. Lastly, the function of NNMT and its product 1-methyl-nicotinamide (1-MNA) on migration and invasion in colorectal cancer cells was analyzed by wound healing assay and transwell assay. Results: We determined that higher NNMT expression in CRC tissues than normal tissues in both gene and protein level in TCGA and CPTAC datasets (all p < 0.05). In addition, the strong relationships of NNMT expression with stromal cells were found in the TCGA cohort. Fortunately, our cohort could validate that the expression of NNMT in tumor stroma cell was significantly higher than that in tumor cell (p < 0.0001), and both of them were significantly higher than that in adjacent normal tissue (ANT) (p < 0.0001 and p < 0.0001, respectively). Furthermore, the positive NNMT expression in tumor cell and stromal cell were associated with series of unfavorable clinical characteristics, including advanced TNM stage, lymph node metastasis, distant metastasis (all p < 0.05). Also, higher NNMT was associated with unfavorable survival both in our study and public datasets, including TCGA and two Gene Expression Omnibus (GEO) datasets (GSE33113 and GSE17538). Moreover, the functional experiments showed that stromal cells with high NNMT expression can secret 1-MAN to promote migration and invasion of CRC cells in vitro. Conclusions: In CRC, NNMT is overexpressed in tumor cells and stroma cells, and then mainly expressed in tumor stroma cells. Overexpression of NNMT in tumor cell and stroma cell both are associated with metastasis and unfavorable survival. Besides, stromal cells with high NNMT expression secrets 1-MAN to promote migration and invasion of CRC cells. Therefore, NNMT may be a potential prognostic indicator in CRC patients.

Combinatorial Approaches for Cancer Treatment Using Oncolytic Viruses: Projecting the Perspectives through Clinical Trials Outcomes

Recent cancer immunotherapy breakthroughs have fundamentally changed oncology and revived the fading hope for a cancer cure. The immune checkpoint inhibitors (ICI) became an indispensable tool for the treatment of many malignant tumors. Alongside ICI, the application of oncolytic viruses in clinical trials is demonstrating encouraging outcomes. Dozens of combinations of oncolytic viruses with conventional radiotherapy and chemotherapy are widely used or studied, but it seems quite complicated to highlight the most effective combinations. Our review summarizes the results of clinical trials evaluating oncolytic viruses with or without genetic alterations in combination with immune checkpoint blockade, cytokines, antigens and other oncolytic viruses as well. This review is focused on the efficacy and safety of virotherapy and the most promising combinations based on the published clinical data, rather than presenting all oncolytic virus variations, which are discussed in comprehensive literature reviews. We briefly revise the research landscape of oncolytic viruses and discuss future perspectives in virus immunotherapy, in order to provide an insight for novel strategies of cancer treatment.

Evidence-Based Medicine in Oncology: Commercial Versus Patient Benefit

At times of personalized and individualized medicine the concept of randomized- controlled clinical trials (RCTs) is being questioned. This review article explains principles of evidence-based medicine in oncology and shows an example of how evidence can be generated independently from RCTs. Personalized medicine involves molecular analysis of tumor properties and targeted therapy with small molecule inhibitors. Individualized medicine involves the whole patient (tumor and host) in the context of immunotherapy. The example is called Individualized Multimodal Immunotherapy (IMI). It is based on the individuality of immunological tumor-host interactions and on the concept of immunogenic tumor cell death (ICD) induced by an oncolytic virus. The evidence is generated by systematic data collection and analysis. The outcome is then shared with the scientific and medical community. The priority of big pharma studies is commercial benefit. Methods used to achieve this are described and have damaged the image of RCT studies in general. A critical discussion is recommended between all partners of the medical health system with regard to the conduct of RCTs by big pharma companies. Several clinics and institutions in Europe try to become more independent from pharma industry and to develop their own modern cancer therapeutics. Medical associations should include references to such studies from personalized and individualized medicine in their guidelines.

Cancer Vaccines and Oncolytic Viruses Exert Profoundly Lower Side Effects in Cancer Patients than Other Systemic Therapies: A Comparative Analysis

This review compares cytotoxic drugs, targeted therapies, and immunotherapies with regard to mechanisms and side effects. Targeted therapies relate to small molecule inhibitors. Immunotherapies include checkpoint inhibitory antibodies, chimeric antigen receptor (CAR) T-cells, cancer vaccines, and oncolytic viruses. All these therapeutic approaches fight systemic disease, be it micro-metastatic or metastatic. The analysis includes only studies with a proven therapeutic effect. A clear-cut difference is observed with regard to major adverse events (WHO grades 3-4). Such severe side effects are not observed with cancer vaccines/oncolytic viruses while they are seen with all the other systemic therapies. Reasons for this difference are discussed.

New Insights into Mechanisms of Long-term Protective Anti-tumor Immunity Induced by Cancer Vaccines Modified by Virus Infection

The topic is how to achieve long-term protective anti-tumor immunity by anti-cancer vaccination and what are its mechanisms. Cancer vaccines should instruct the immune system regarding relevant cancer targets and contain signals for innate immunity activation. Of central importance is T-cell mediated immunity and thus a detailed understanding of cognate interactions between tumor antigen (TA)-specific T cells and TA-presenting dendritic cells. Microbes and their associated molecular patterns initiate early inflammatory defense reactions that can contribute to the activation of antigen-presenting cells (APCs) and to costimulation of T cells. The concommitant stimulation of naive TA-specific CD4+ and CD8+ T cells with TAs and costimulatory signals occurs in T-APC clusters that generate effectors, such as cytotoxic T lymphocytes and T cell mediated immunological memory. Information about how such memory can be maintained over long times is updated. The role that the bone marrow with its specialized niches plays for the survival of memory T cells is emphasized. Examples are presented that demonstrate long-term protective anti-tumor immunity can be achieved by post-operative vaccination with autologous cancer vaccines that are modified by virus infection.

Bone marrow expands the repertoire of functional T cells targeting tumor-associated antigens in patients with resectable non-small-cell lung cancer

The efficacy of cancer immunotherapy may be improved by increasing the number of circulating tumor-reactive T cells. The bone marrow is a priming site and reservoir for such T cells. The characteristics of bone marrow-derived tumor-reactive T cells are poorly understood in patients with non-small-cell lung cancer (NSCLC). To compare the responsiveness of tumor antigen-reactive T cells from the bone marrow with matched peripheral blood samples in patients with resectable NSCLC, we used flow cytometry, cytokine capture assays and enzyme-linked immunospot assays to examine the responsiveness of T cells to 14 tumor antigens in matched bone marrow and peripheral blood samples from patients with resectable NSCLC or benign tumors and tumor-free patients. T cells with reactivity to tumor antigens were detected in the bone marrow of 20 of 39 (51%) NSCLC patients. The panel of tumor antigens recognized by bone marrow-derived T cells was distinct from that recognized by peripheral blood-derived T cells in NSCLC patients. Unlike for peripheral blood T cells, the presence of tumor-reactive T cells in the bone marrow did not correlate with recurrence-free survival after curative intent resection of NSCLC. T cells with reactivity to tumor antigens are common in the bone marrow of patients with NSCLC. Tumor-reactive T cells of the bone marrow have the potential to significantly broaden the total repertoire of tumor-reactive T cells in the body. To clarify the role of tumor-reactive T cells of the bone marrow in T cell-based immunotherapy approaches, clinical studies are needed (ClinicalTrials.gov: NCT02515760).

Breaking Therapy Resistance: An Update on Oncolytic Newcastle Disease Virus for Improvements of Cancer Therapy

Resistance to therapy is a major obstacle to cancer treatment. It may exist from the beginning, or it may develop during therapy. The review focusses on oncolytic Newcastle disease virus (NDV) as a biological agent with potential to break therapy resistance. This avian virus combines, upon inoculation into non-permissive hosts such as human, 12 described anti-neoplastic effects with 11 described immune stimulatory properties. Fifty years of clinical application of NDV give witness to the high safety profile of this biological agent. In 2015, an important milestone was achieved, namely the successful production of NDV according to Good Manufacturing Practice (GMP). Based on this, IOZK in Cologne, Germany, obtained a GMP certificate for the production of a dendritic cell vaccine loaded with tumor antigens from a lysate of patient-derived tumor cells together with immunological danger signals from NDV for intracutaneous application. This update includes single case reports and retrospective analyses from patients treated at IOZK. The review also presents future perspectives, including the concept of in situ vaccination and the combination of NDV or other oncolytic viruses with checkpoint inhibitors.

Application of Newcastle disease virus in the treatment of colorectal cancer

Colorectal cancer (CRC) is one of the main reasons of tumor-related deaths worldwide. At present, the main treatment is surgery, but the results are unsatisfactory, and the prognosis is poor. The majority of patients die due to liver or lung metastasis or recurrence. In recent years, great progress has been made in the field of tumor gene therapy, providing a new treatment for combating CRC. As oncolytic viruses selectively replicate almost exclusively in the cytoplasm of tumor cells and do not require integration into the host genome, they are safer, more effective and more attractive as oncolytic agents. Newcastle disease virus (NDV) is a natural RNA oncolytic virus. After NDV selectively infects tumor cells, the immune response induced by NDV’s envelope protein and intracellular factors can effectively kill the tumor without affecting normal cells. Reverse genetic techniques make NDV a vector for gene therapy. Arming the virus by inserting various exogenous genes or using NDV in combination with immunotherapy can also improve the anti-CRC capacity of NDV, and good results have been achieved in animal models and clinical treatment trials. This article reviews the molecular biological characteristics and oncolytic mechanism of NDV and discusses in vitro and in vivo experiments on NDV anti-CRC capacity and clinical treatment. In conclusion, NDV is an excellent candidate for cancer treatment, but more preclinical studies and clinical trials are needed to ensure its safety and efficacy.

Novel approaches for the design, delivery and administration of vaccine technologies

It is easy to argue that vaccine development represents humankind's most important and successful endeavour, such is the impact that vaccination has had on human morbidity and mortality over the last 200 years. During this time the original method of Jenner and Pasteur, i.e. that of injecting live-attenuated or inactivated pathogens, has been developed and supplemented with a wide range of alternative approaches which are now in clinical use or under development. These next-generation technologies have been designed to produce a vaccine that has the effectiveness of the original live-attenuated and inactivated vaccines, but without the associated risks and limitations. Indeed, the method of development has undoubtedly moved away from Pasteur's three Is paradigm (isolate, inactivate, inject) towards an approach of rational design, made possible by improved knowledge of the pathogen-host interaction and the mechanisms of the immune system. These novel vaccines have explored methods for targeted delivery of antigenic material, as well as for the control of release profiles, so that dosing regimens can be matched to the time-lines of immune system stimulation and the realities of health-care delivery in dispersed populations. The methods by which vaccines are administered are also the subject of intense research in the hope that needle and syringe dosing, with all its associated issues regarding risk of injury, cross-infection and patient compliance, can be replaced. This review provides a detailed overview of new vaccine vectors as well as information pertaining to the novel delivery platforms under development.

From chemotherapy to biological therapy: A review of novel concepts to reduce the side effects of systemic cancer treatment (Review)

The side effects of systemic chemotherapy used to treat cancer are often severe. For decades, oncologists have focused on treating the tumor, which may result in damage to the tumor-bearing host and its immune system. Recently, much attention has been paid to the immune system of patients and its activation via biological therapies. Biological therapies, including immunotherapy and oncolytic virus (OV) therapy, are often more physiological and well tolerated. The present review elucidated how these therapies work and why these therapies may be better tolerated: i) In contrast to chemotherapy, immunotherapies induce a memory function of the adaptive immunity system; ii) immunotherapies aim to specifically activate the immune system against cancer; side effects are low due to immune tolerance mechanisms, which maintain the integrity of the body in the presence of B and T lymphocytes with their antigen-receptor specificities and; iii) the type I interferon response, which is evoked by OVs, is an ancient innate immune defense system. Biological and physiological therapies, which support the immune system, may therefore benefit cancer treatment. The present review focused on immunotherapy, with the aim of reducing side effects and increasing long-lasting efficacy in cancer therapy.

Heat shock protein peptide complex-96 vaccination for newly diagnosed glioblastoma: a phase I, single-arm trial

BACKGROUND

Heat shock protein peptide complex-96 (HSPPC-96) triggers adaptive and innate antitumor immune responses. The safety and efficacy of HSPPC-96 vaccination was examined in patients with newly diagnosed glioblastoma multiforme (GBM).

METHODS

In this open-label, single-arm, phase I study, adult patients were vaccinated with HSPPC-96 in combination with the standard treatment for newly diagnosed GBM after surgical resection. Primary endpoints were frequency of adverse events and progression-free survival (PFS) at 6 months. Secondary endpoints included overall survival (OS), PFS, and tumor-specific immune response (TSIR).

RESULTS

A total of 20 patients with newly diagnosed GBM were enrolled from September 2013 to February 2015. No grade 3 or 4 vaccine-related adverse events were noted. After a median follow-up of 42.3 months, PFS was 89.5% (95% CI, 66.9%-98.7%) at 6 months, median PFS was 11.0 months (95% CI, 8.2-13.8), and median OS was 31.4 months (95% CI, 14.9-47.9). TSIR was significantly increased by 2.3-fold (95% CI, 1.7-3.2) after vaccination. Median OS for patients with high TSIR after vaccination was >40.5 months (95% CI, incalculable) as compared with 14.6 months (95% CI, 7.0-22.2) for patients with low TSIR after vaccination (hazard ratio, 0.25; 95% CI, 0.071-0.90; P = 0.034). A multivariate Cox regression model revealed TSIR after vaccination as a primary independent predicator for survival.

CONCLUSION

The HSPPC-96 vaccination, combined with the standard therapy, is a safe and effective strategy for treatment of newly diagnosed GBM patients. TSIR after vaccination would be a good indicator predicting the vaccine efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02122822.

FUNDING

National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2014BAI04B01, 2014BAI04B02), Beijing Natural Science Foundation (7164253), Beijing Talents Fund (2014000021469G257), and Shenzhen Science and Technology Innovation Committee (JSGG20170413151359491).

Post-operative unadjuvanted therapeutic xenovaccination with chicken whole embryo vaccine suppresses distant micrometastases and prolongs survival in a murine Lewis lung carcinoma model

Immunotherapy in the form of anticancer vaccination relies on the mobilization of the patient's immune system against specific cancer antigens. Instead of focusing on an autologous cell lysate, which is not always available in clinical practice, the present study investigates vaccines utilizing xenogeneic foetal tissue that are rich in oncofoetal antigens. Lewis lung carcinoma (LLC)-challenged C57BL/6 mice were treated with either a xenogeneic vaccine made from chicken whole embryo, or a xenogeneic vaccine made from rat embryonic brain tissue, supplemented with a Bacillus subtilis protein fraction as an adjuvant. Median and overall survival, size of metastatic foci in lung tissue and levels of circulating CD8a⁺ T cells were evaluated and compared with untreated control mice. Following primary tumour removal, a course of three subcutaneous vaccinations with xenogeneic chicken embryo vaccine led to significant increase in overall survival rate (100% after 70 days of follow-up vs. 40% in untreated control mice), significant increase in circulating CD8a⁺ T cells (18.18 vs. 12.6% in untreated control mice), and a significant decrease in the area and incidence of metastasis foci. The xenogeneic rat brain tissue-based vaccine did not improve any of the investigated parameters, despite promising reports in other models. We hypothesize that the proper selection of antigen source (tissue) can constitute an effective immunotherapeutic product.

Immunobiology of Newcastle Disease Virus and Its Use for Prophylactic Vaccination in Poultry and as Adjuvant for Therapeutic Vaccination in Cancer Patients

Newcastle disease (ND) is one of the most important diseases of poultry worldwide. In the last decades, molecular research has gained a lot of new information about its causative agent, newcastledisease virus (NDV). In poultry industry, certain strains of NDV have been used for preventive vaccination for more than 60 years. NDV has also been applied to cancer patients with beneficial effects for about 50 years, but this is less well known. The molecular basis for these differential effects of NDV in birds and man have been elucidated in the last decades and are explained in this review. The anti-neoplastic and immune-stimulatory properties in non-permissive hosts such as mouse and man have to do with the strong type I interferon responses induced in these foreign species. Additionally, NDV has the potential to break various types of tumor resistances and also to affect liver fibrosis. A main section is devoted to the benefits of clinical application of NDV and NDV-based vaccines to cancer patients. Reverse genetics technology allowed developing NDV into a vector suitable for gene therapy. Examples will be provided in which genetically engineered NDV is being used successfully as vector against new emerging viruses.

Co-expression of TIM-3 and CEACAM1 promotes T cell exhaustion in colorectal cancer patients

T-cell immunoglobulin domain and mucin domain-3(TIM-3) is an activation induced inhibitory molecule involved in immune tolerance and is recently reported to induce T cell exhaustion which is mediated by carcinoembryonic antigen cell adhesion molecule 1(CEACAM1), another well-known molecule expressed on activated T cells and involved in T cell inhibition. To investigate the expression of TIM-3 and CEACAM1 on circulating CD8⁺ T cells and tumor infiltrating lymphocytes (TILs), 65 diagnosed colorectal cancer (CRC) patients and 38 healthy controls were enrolled in this study and the results showed that TIM-3 and CEACAM1 were both highly expressed on circulating CD8⁺ T cells in CRC patients and elevated on TILs compared with paraneoplastic T cells. Furthermore, TIM-3⁺CEACAM1⁺ CD8⁺ T cells represented the most dysfunctional population with the least IFN-γ production. In addition, the expressions of TIM-3 and CEACAM1 were correlated with advanced stage and could be independent risk factors for CRC. We for the first time to our knowledge suggested that co-expression of TIM-3 and CEACAM1 can mediate T cell exhaustion and may be potential biomarkers for CRC prediction, highlighting the possibility of being immunotherapy targets.

Targeting PD-1 and Tim-3 Pathways to Reverse CD8 T-Cell Exhaustion and Enhance Ex Vivo T-Cell Responses to Autologous Dendritic/Tumor Vaccines

The paradoxical coexistence of spontaneous tumor antigen-specific immune response with progressive disease in cancer patients need to dissect the molecular pathways involved in tumor-induced T-cell dysfunction or exhaustion. Programmed cell death 1 (PD-1) has been identified as a marker of exhausted T cells in chronic disease states, and blockade of PD-1-PD-L1 interactions has been shown to partially restore T-cell function. We have found that T-cell immunoglobulin mucin (Tim) 3 is expressed on CD8+ tumor-infiltrating lymphocytes (TILs) isolated from patients with colorectal cancer. All T-cell immunoglobulin mucin 3 (Tim-3+) TILs coexpress PD-1, and Tim-3+ PD-1+ CD8+ TILs represent the predominant fraction of Tcells infiltrating tumors. Tim-3+PD-1+ CD8+ TILs exhibit the most severe exhausted phenotype as defined by failure to produce cytokines, such as interferon-γ, tumor necrosis factor-α, and interleukin-2. We further find that combined targeting of the Tim-3 and PD-1 pathways increased the frequencies of not only interferon-γ and tumor necrosis factor-α but also frequencies of proliferating tumor antigen-specific CD8+ T cells than targeting either pathway alone. A concomitant decrease in regulatory T cells and enhanced killing in a cytotoxicity assay was observed. Collectively, our findings support the use of Tim-3-Tim-3L blockade together with PD-1-PD-L1 blockade to reverse tumor-induced T-cell exhaustion/dysfunction in patients with colorectal cancer.

Bacterial ghosts as adjuvants in syngeneic tumour cell lysate-based anticancer vaccination in a murine lung carcinoma model

Instead of relying on external anticancer factors for treatment, immunotherapy utilizes the host's own immune system and directs it against given tumour antigens. This study demonstrated that it is possible to overcome the documented immunosuppressive properties of tumour cell lysate by supplementing it with appropriate adjuvant. Lewis lung carcinoma (LLC)‑challenged C57BL/6 mice were treated with LLC cryo‑lysate mixed with either bacterial ghosts (BGs) generated from E. coli Nissle 1917 or B. subtilis 70 kDa protein as adjuvants. Median and overall survival, the size of metastatic foci in lung tissue and levels of circulating CD8a+ T cells were evaluated and compared to the untreated control mice or mice treated with LLC lysate alone. After primary tumour removal, a course of three subcutaneous vaccinations with LLC lysate supplemented with BGs led to a significant increase in overall survival (80% after 84 days of follow‑up vs. 40% in untreated control mice), a significant increase in circulating CD8a+ T cells (16.57 vs. 12.6% in untreated control mice) and a significant decrease in metastasis foci area and incidence. LLC lysate supplemented with B. subtilis protein also improved the inspected parameters in the treated mice, when compared against the untreated control mice, but not to a significant degree. Therefore, whole cell lysate supplemented with BGs emerges as an immunostimulatory construct with potential clinical applications in cancer treatment.

Association of HMGB1 Gene Polymorphisms with Risk of Colorectal Cancer in a Chinese Population

Background

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. More advanced work is required in the detection of biomarkers for CRC susceptibility and prognosis. High-mobility group box-1 (HMGB1) is an angiogenesis-related gene reported to be associated with the development of CRC. The direct evidence of HMGB1 gene polymorphisms as biomarkers for CRC has not been reported previously.

Material/Methods

A total of 240 CRC patients and 480 healthy controls were periodically enrolled. DNA was extracted from blood specimens. The distributions of SNPs of HMGB1 were determined by using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay.

Results

In this case-control study, we observed a significant association between overall CRC risk and SNP rs2249825 (CG vs. CC and GG vs. CC). Participants carrying both rs2249825 CG (OR, 2.67; 95% CI, 1.89 to 3.78) and rs2249825 GG genotypes (OR, 2.32; 95% CI, 1.13 to 4.73) had a significantly increased risk of developing CRC compared to those carrying GG genotype. rs2249825 was associated with the risk of CRC in the dominant model but not in the recessive model. However, we found no significant differences in the rs1412125 or rs1045411 polymorphisms in the HMGB1. Advanced analyses showed that the number of rs2249825 G alleles showed a significant relationship with risk of CRC.

Conclusions

Our results show an association between HMGB1 rs2249825 SNP and CRC incidence in the Chinese Han population. However, population-based studies with more subjects and prognostic effects are needed to verify the association of HMGB1 SNPs with CRC susceptibility, severity, and long-term prognosis.

Fifty Years of Clinical Application of Newcastle Disease Virus: Time to Celebrate!

This review provides an overview of 50 years of basic and clinical research on an oncolytic avian virus, Newcastle Disease Virus (NDV), which has particular anti-neoplastic and immune stimulatory properties. Of special interest is the fact that this biological agent induces immunogenic cell death and systemic anti-tumor immunity. Furthermore, localized oncolytic virotherapy with NDV was shown to overcome systemic tumor resistance to immune checkpoint blockade immunotherapy. Clinical experience attests to low side effects and a high safety profile. This is due among others to the strong virus-induced type I interferon response. Other viral characteristics are lack of interaction with host cell DNA, lack of genetic recombination and independence of virus replication from cell proliferation. In this millennium, new recombinant strains of viruses are being produced with improved therapeutic properties. Clinical applications include single case observations, case series studies and Phase I to III studies.

Circulating and tumor-infiltrating Tim-3 in patients with colorectal cancer

T-cell exhaustion represents a progressive loss of T-cell function. The inhibitory receptor PD-1 is known to negatively regulate CD8+ T cell responses directed against tumor antigen, but the blockades of PD-1 pathway didn't show the objective responses in patients with colorectal cancer (CRC). Thus, further exploring the molecular mechanism responsible for inducing T-cell dysfunction in CRC patients may reveal effective strategies for immune therapy. This study aims to characterize co-inhibitory receptors on T cells in CRC patients to identify novel targets for immunotherapy. In this study, peripheral blood samples from 20 healthy controls and 54 consented CRC patients, and tumor and matched paraneoplastic tissues from 7 patients with advanced CRC, subjected to multicolor flow cytometric analysis of the expression of PD-1 and Tim-3 receptors on CD8+ T cells. It was found that CRC patients presented with significantly higher levels of circulating Tim-3+PD-1+CD8+ T cells compared to the healthy controls (medians of 3.12% and 1.99%, respectively, p = 0.0403). A similar increase of Tim-3+PD-1+CD8+ T cells was also observed in the tumor tissues compared to paraneoplastic tussues. Tim-3+PD-1+CD8+ T cells in tumor tissues produced even less cytokine than that in paraneoplastic tissues. Functional ex vivo experiments showed that Tim-3+PD-1+CD8+ T cells produced significantly less IFN-γ than Tim-3-PD-1-CD8+ T cells, followed by Tim-3+PD-1-CD8+ T cells, and Tim-3-PD-1+CD8+ T cells, indicating a stronger inhibition of IFN-γ production of Tim-3+CD8+ T cells . It is also found in this study that Tim-3+PD-1+CD8+ T cell increase in circulation was correlated with clinical cancer stage but not histologic grade and serum concentrations of cancer biomarker CEA. Our results indicate that upregulation of the inhibitory receptor Tim-3 may restrict T cell responses in CRC patients, and therefore blockage of Tim-3 and thus restoring T cell responses may be a potential therapeutic approach for CRC patients.

Cancer-reactive memory T cells from bone marrow: Spontaneous induction and therapeutic potential (Review)

Cognate interactions between naïve tumor antigen (TA)-specific T cells and TA-presenting dendritic cells (DCs) are facilitated by secondary lymphoid organs such as lymph nodes or the spleen. These can result either in TA-specific tolerance or, depending on environmental costimulatory signals, in TA-specific immune responses. In the present review, we describe such events for the bone marrow (BM) when blood-borne TA, released from the primary tumor or expressed by blood circulating tumor cells or DCs enters the BM stroma and parenchyma. We argue that cognate T-DC interactions in the BM result in immune responses and generation of memory T cells (MTCs) rather than tolerance because T cells in the BM show an increased level of pre-activation. The review starts with the spontaneous induction of cancer-reactive MTCs in the BM and the involvement of such MTCs in the control of tumor dormancy. The main part deals with the therapeutic potency of BM MTCs. This is a new area of research in which the authors research group has performed pioneering studies which are summarized. These include studies in animal tumor models, studies with human cells in tumor xenotransplant models and clinical studies. Based on observations of an enormous expansion capacity, longevity and therapeutic capacity of BM MTCs, a hypothesis is presented which suggests the involvement of stem-like MTCs.

Validity of combination active specific immunotherapy for colorectal cancer: a meta-analysis of 2993 patients

BACKGROUND AIMS

The aim of this study was to investigate whether active specific immunotherapy (ASI) is able to demonstrate therapeutic efficacy against colorectal cancer.

METHODS

We conducted a systematic review of published papers from MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, the Wanfang Database, the China Science and Technology Periodical Database and China Journal Net. Published data were extracted independently by two authors who used predefined database templates. The effects of ASI were compared with those of surgery alone, and a pooled analysis was performed with the use of the data from random- or fixed-effect models.

RESULTS

Twelve trials matched our inclusion criteria (n = 2993, including 1842 control subjects). The overall analysis showed a significant survival benefit [1-, 2-, 3-, 4-, 5-, 6- and 7-year overall survival (OS), P < 0.05; 10-year OS, P < 0.001] in favor of ASI immunotherapy combined with surgery, but there was not an improvement in the 8- or 9-year OS (P > 0.05). The disease-free survival (DFS) rate was improved after the combination of ASI immunotherapy (2-, 3-, 5- and 10-year DFS, P < 0.05), but no significant improvement was noted for the 1-, 4-, 6-, 7-, 8- or 9-year DFS (P > 0.05). In addition, the disease-specific survival (DSS) was improved at some time points after the combination of ASI immunotherapy and surgery (2-, 3-, 4-, 5- and 6-year DSS, P < 0.05, but not the 1-, 7-, 8- or 9-year DSS, P > 0.05). An improved 2-, 3-, 4-, 5- and 6-year recurrence-free interval (RFI) (P < 0.05) was also observed in patients who received ASI therapy, but this was not observed for the 1-year RFI (P > 0.05). Furthermore, an analysis of the recurrence-free survival (RFS) showed that it was significantly increased in the ASI plus surgery group (1-, 2-, 3-, 4-, 5- and 6-year RFS, P < 0.001). The funnel plots showed that the analyses were relatively reliable and the publication bias was small.

CONCLUSIONS

The combination of ASI immunotherapy and surgery was superior in prolonging the overall survival time and enhancing the recurrence-free survival rate compared with surgery alone.

Oncolytic Newcastle disease virus as a prospective anti-cancer therapy. A biologic agent with potential to break therapy resistance

INTRODUCTION

Oncolytic viruses (OVs) selectively replicate in tumor cells and cause cancer cell death. Most OVs in clinical studies are genetically engineered. In contrast, the avian Newcastle disease virus (NDV) is a naturally oncolytic RNA virus. While anti-viral immunity is considered a major problem in achieving maximal tumor cell killing by OVs, this review discusses the importance of NDV immunogenic cell death (ICD) and how anti-viral immune responses can be integrated to induce maximal post-oncolytic T-cell-mediated anti-tumor immunity. Since replication of NDV is independent of host cell DNA replication (which is the target of many cytostatic drugs and radiotherapy) and because of other findings, oncolytic NDV is a candidate agent to break therapy resistance of tumor cells.

AREAS COVERED

Properties of this avian paramyxovirus are summarized with special emphasis to its anti-neoplastic and immune-stimulatory properties. The review then discusses prospective anti-cancer therapies, including treatments with NDV alone, and combinations with an autologous NDV-modified tumor cell vaccine or with a viral oncolysate pulsed dendritic cell vaccine. Various combinatorial approaches between these and with other modalities are also reviewed.

EXPERT OPINION

Post-oncolytic anti-tumor immunity based on ICD is in the expert's opinion of greater importance for long-term therapeutic effects than maximal tumor cell killing. Of the various combinatorial approaches discussed, the most promising and feasible for clinical practice appears to be the combination of systemic NDV pre-treatment with anti-tumor vaccination.

Autologous tumor lysate/Bacillus Calmette-Guérin immunotherapy as an adjuvant to conventional breast cancer therapy

Introduction

Autologous tumor cell vaccines rely on the concept of preserving an individual’s own tumorigenic makeup, expressing its unique set of tumor-associated antigens as well as antigenic elements from the surrounding stroma. These autologous tumor characteristics are usually presented with an immune adjuvant in the hopes of enhancing an immune response.

Methods

The autologous vaccine we used was composed of tumor cells combined with BCG and formalin. Animal safety and toxicity were evaluated using mice tumors for the immunotherapy. A small number of patients with advanced stage breast cancer were recruited for an uncontrolled study, using the vaccine solely or combined with chemotherapy/radiotherapy.

Results

The immunotherapy had shown to be safe in mice and humans. Upon a 5-year follow-up, the survival rate was 60 % for the combined treatment.

Conclusions

The data suggest that the combined treatment could be a feasible and safe therapeutic strategy. However, further controlled studies should be conducted.

Long-term remission of prostate cancer with extensive bone metastases upon immuno- and virotherapy: A case report

The present study reports the case of a patient with hormone-refractory metastatic prostate cancer who had failed standard therapy, but then achieved complete remission following combined treatment with local hyperthermia (LHT), Newcastle disease virus and dendritic cell (DC) vaccination, which was an unusual combination. In August 2005, the patient underwent a radical prostatectomy. Despite standard treatment, the patient developed progressive bone metastases and stopped conventional therapy in June 2007. Starting in October 2007, the patient was treated with LHT, oncolytic virotherapy and DC vaccination. Prostate-specific antigen (PSA)-levels, with the highest level of 233.8 ng/ml in January 2008, decreased to 0.8 ng/ml in late February 2008. In March 2008, a reduction in bone metastases could be detected by positron emission tomography/computed tomography. Since then, the PSA levels have remained low and the patient is doing well. The treatment induced a long-lasting antitumor memory T-cell response. This possibly explains the long-term effectiveness of this novel experimental combined treatment approach.