In vitro induction of carcinoembryonic antigen (CEA)-specific cytotoxic T lymphocytes by dendritic cells transduced with recombinant adenoviruses

Recent advances in CAR T-cell engineering using synthetic biology: Paving the way for next-generation cancer treatment

This book chapter highlights a comprehensive exploration of the transformative innovations in the field of cancer immunotherapy. CAR (Chimeric Antigen Receptor) T-cell therapy represents a groundbreaking approach to treat cancer by reprogramming a patient immune cells to recognize and destroy cancer cells. This chapter underscores the critical role of synthetic biology in enhancing the safety and effectiveness of CAR T-cell therapies. It begins by emphasizing the growing importance of personalized medicine in cancer treatment, emphasizing the shift from one-size-fits-all approaches to patient-specific solutions. Synthetic biology, a multidisciplinary field, has been instrumental in customizing CAR T-cell therapies, allowing for fine-tuned precision and minimizing unwanted side effects. The chapter highlights recent advances in gene editing, synthetic gene circuits, and molecular engineering, showcasing how these technologies are optimizing CAR T-cell function. In summary, this book chapter sheds light on the remarkable progress made in the development of CAR T-cell therapies using synthetic biology, providing hope for cancer patients and hinting at a future where highly personalized and effective cancer treatments are the norm.

A Multiple-Array SPRi Biosensor as a Tool for Detection of Gynecological-Oncological Diseases

Diagnostics based on the determination of biomarkers in body fluids will be more successful when several biomarkers are determined. A multiple-array SPRi biosensor for the simultaneous determination of CA125, HE4, CEA, IL-6 and aromatase has been developed. Five individual biosensors were placed on the same chip. Each of them consisted of a suitable antibody covalently immobilized onto a gold chip surface via a cysteamine linker by means of the NHS/EDC protocol. The biosensor for IL-6 works in the pg mL^-1 range, that for CA125 in the µg mL^-1 range, and the other three within the ng mL^-1 range; these are ranges suitable for the determination of biomarkers in real samples. The results obtained with the multiple-array biosensor are very similar to those obtained with a single biosensor. The applicability of the multiple biosensor was demonstrated using several examples of plasma from patients suffering from ovarian cancer and endometrial cyst. The average precision was 3.4% for the determination of CA125, 3.5% for HE4, 5.0% for CEA and IL-6, and 7.6% for aromatase. The simultaneous determination of several biomarkers may be an excellent tool for the screening of the population for earlier detection of diseases.

Breast cancer vaccines: New insights into immunomodulatory and nano-therapeutic approaches

Breast cancer (BC) is known to be a highly heterogeneous disease that is clinically subdivided into four primary molecular subtypes, each having distinct morphology and clinical implications. These subtypes are principally defined by hormone receptors and other proteins involved (or not involved) in BC development. BC therapeutic vaccines [including peptide-based vaccines, protein-based vaccines, nucleic acid-based vaccines (DNA/RNA vaccines), bacterial/viral-based vaccines, and different immune cell-based vaccines] have emerged as an appealing class of cancer immunotherapeutics when used alone or combined with other immunotherapies. Employing the immune system to eliminate BC cells is a novel therapeutic modality. The benefit of active immunotherapies is that they develop protection against neoplastic tissue and readjust the immune system to an anti-tumor monitoring state. Such immunovaccines have not yet shown effectiveness for BC treatment in clinical trials. In recent years, nanomedicines have opened new windows to increase the effectiveness of vaccinations to treat BC. In this context, some nanoplatforms have been designed to efficiently deliver molecular, cellular, or subcellular vaccines to BC cells, increasing the efficacy and persistence of anti-tumor immunity while minimizing undesirable side effects. Immunostimulatory nano-adjuvants, liposomal-based vaccines, polymeric vaccines, virus-like particles, lipid/calcium/phosphate nanoparticles, chitosan-derived nanostructures, porous silicon microparticles, and selenium nanoparticles are among the newly designed nanostructures that have been used to facilitate antigen internalization and presentation by antigen-presenting cells, increase antigen stability, enhance vaccine antigenicity and remedial effectivity, promote antigen escape from the endosome, improve cytotoxic T lymphocyte responses, and produce humoral immune responses in BC cells. Here, we summarized the existing subtypes of BC and shed light on immunomodulatory and nano-therapeutic strategies for BC vaccination. Finally, we reviewed ongoing clinical trials on BC vaccination and highlighted near-term opportunities for moving forward.

Role of Immune Cells in Patients with Hepatitis B Virus-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) develops almost entirely in the presence of chronic inflammation. Chronic hepatitis B virus (HBV) infection with recurrent immune-mediated liver damage ultimately leads to cirrhosis and HCC. It is widely accepted that HBV infection induces the dysfunction of the innate and adaptive immune responses that engage various immune cells. Natural killer (NK) cells are associated with early antiviral and antitumor properties. On the other hand, inflammatory cells release various cytokines and chemokines that may promote HCC tumorigenesis. Moreover, immunosuppressive cells such as regulatory T cells (Treg) and myeloid-derived suppressive cells play a critical role in hepatocarcinogenesis. HBV-specific CD8+ T cells have been identified as pivotal players in antiviral responses, whilst extremely activated CD8+ T cells induce enormous inflammatory responses, and chronic inflammation can facilitate hepatocarcinogenesis. Controlling and maintaining the balance in the immune system is an important aspect in the management of HBV-related HCC. We conducted a review of the current knowledge on the immunopathogenesis of HBV-induced inflammation and the role of such immune activation in the tumorigenesis of HCC based on the recent studies on innate and adaptive immune cell dysfunction in HBV-related HCC.

An immunosensor for the determination of carcinoembryonic antigen by Surface Plasmon Resonance imaging

Carcinoembryonic antigen (CEA) is one of the biomarkers most commonly used to determine tumor activity. In this work, a Surface Plasmon Resonance imaging (SPRi) immunosensor was developed. The immunosensor consists of a cysteamine linker attached to a gold chip and mouse monoclonal anti-CEA antibody bonded by the "EDC/NHS protocol". The formation of successive immunosensor layers was confirmed by AFM measurements. The concentration of the antibody was optimized. The linear response range of the developed immunosensor is between 0.40 and 20 ng mL^-1, and it is suitable for CEA measurement in both blood cancer patients and healthy individuals. Only 3 μL of serum or plasma sample is required, and no preconcentration is used. The method has a precision of 2-16%, a recovery of 101-104% depending on CEA concentration, a detection limit of 0.12 ng mL^-1 and a quantification limit of 0.40 ng mL^-1. The method is selective (with respect to albumin, leptin, interleukin 6, metalloproteinase-1, metallopeptidase inhibitor 1 and CA 125/MUC16) and it was validated by comparison with the standard electrochemiluminescence method on a series of colorectal cancer blood samples.

Adenovirus vectors in hematopoietic stem cell genome editing

Genome editing of hematopoietic stem cells (HSCs) represents a therapeutic option for a number of hematological genetic diseases, as HSCs have the potential for self-renewal and differentiation into all blood cell lineages. This review presents advances of genome editing in HSCs utilizing adenovirus vectors as delivery vehicles. We focus on capsid-modified, helper-dependent adenovirus vectors that are devoid of all viral genes and therefore exhibit an improved safety profile. We discuss HSC genome engineering for several inherited disorders and infectious diseases including hemoglobinopathies, Fanconi anemia, hemophilia, and HIV-1 infection by ex vivo and in vivo editing in transgenic mice, nonhuman primates, as well as in human CD34+ cells. Mechanisms of therapeutic gene transfer including episomal expression of designer nucleases and base editors, transposase-mediated random integration, and targeted homology-directed repair triggered integration into selected genomic safe harbor loci are also reviewed.

Immunotherapy for Lewis lung carcinoma utilizing dendritic cells infected with CK19 gene recombinant adenoviral vectors

Dendritic cells (DCs) as 'professional' antigen-presenting cells (APCs) initiate and regulate immune responses to various antigens. DC-based vaccines have become a promising modality in cancer immunotherapy. Cytokeratin 19 (CK19) protein is expressed at high levels in lung cancer and many other tumor cells, suggesting CK19 as a potential tumor-specific target for cancer immune therapy. We constructed a recombinant adenoviral vector containing the CK19 gene (rAd-CK19). DCs transfected with rAd-CK19 were used to vaccinate C57BL/6 mice bearing xenografts derived from Lewis lung carcinoma (LLC) cells. The transfected DCs gave rise to potent CK19-specific cytotoxic T lymphocytes (CTLs) capable of lysing LLC cells. Mice immunized with the rAd-CK19-DCs exhibited significantly attenuated tumor growth (including tumor volume and weight) when compared to the tumor growth of mice immunized with rAd-c DCs or DCs during the 24-day observation period (P<0.05). The results revealed that the mice vaccinated with the rAd-CK19-DCs exhibited a potent protective and therapeutic antitumor immunity to LLC cells in the subcutaneous model along with an inhibitive effect on tumor growth compared to the mice vaccinated with the rAd-c DCs or DCs alone. The present study proposes a meaningful mode of action utilizing rAd-CK19 DCs in lung cancer immunotherapy.

Adenovirus-based vaccines for fighting infectious diseases and cancer: progress in the field

The field of adenovirology is undergoing rapid change in response to increasing appreciation of the potential advantages of adenoviruses as the basis for new vaccines and as vectors for gene and cancer therapy. Substantial knowledge and understanding of adenoviruses at a molecular level has made their manipulation for use as vaccines and therapeutics relatively straightforward in comparison with other viral vectors. In this review we summarize the structure and life cycle of the adenovirus and focus on the use of adenovirus-based vectors in vaccines against infectious diseases and cancers. Strategies to overcome the problem of preexisting antiadenovirus immunity, which can hamper the immunogenicity of adenovirus-based vaccines, are discussed. When armed with tumor-associated antigens, replication-deficient and oncolytic adenoviruses can efficiently activate an antitumor immune response. We present concepts on how to use adenoviruses as therapeutic cancer vaccines and consider some of the strategies used to further improve antitumor immune responses. Studies that explore the prospect of adenoviruses as vaccines against infectious diseases and cancer are underway, and here we give an overview of the latest developments.

Efficient clinical scale gene modification via zinc finger nuclease-targeted disruption of the HIV co-receptor CCR5

Since HIV requires CD4 and a co-receptor, most commonly C-C chemokine receptor 5 (CCR5), for cellular entry, targeting CCR5 expression is an attractive approach for therapy of HIV infection. Treatment of CD4(+) T cells with zinc-finger protein nucleases (ZFNs) specifically disrupting chemokine receptor CCR5 coding sequences induces resistance to HIV infection in vitro and in vivo. A chimeric Ad5/F35 adenoviral vector encoding CCR5-ZFNs permitted efficient delivery and transient expression following anti-CD3/anti-CD28 costimulation of T lymphocytes. We present data showing CD3/CD28 costimulation substantially improved transduction efficiency over reported methods for Ad5/F35 transduction of T lymphocytes. Modifications to the laboratory scale process, incorporating clinically compatible reagents and methods, resulted in a robust ex vivo manufacturing process capable of generating >10(10) CCR5 gene-edited CD4+ T cells from healthy and HIV+ donors. CD4+ T-cell phenotype, cytokine production, and repertoire were comparable between ZFN-modified and control cells. Following consultation with regulatory authorities, we conducted in vivo toxicity studies that showed no detectable ZFN-specific toxicity or T-cell transformation. Based on these findings, we initiated a clinical trial testing the safety and feasibility of CCR5 gene-edited CD4+ T-cell transfer in study subjects with HIV-1 infection.

A pilot safety trial investigating a vector-based vaccine targeting carcinoembryonic antigen in combination with radiotherapy in patients with gastrointestinal malignancies metastatic to the liver

OBJECTIVE

Previous studies have demonstrated the ability of non-lethal doses of radiation to alter the phenotype of tumor cells to facilitate immune mediated killing. This pilot study evaluated the tolerability of a vector-based vaccine targeting carcinoembryonic antigen (CEA) in combination with radiation therapy in patients with gastrointestinal malignancies metastatic to the liver.

METHODS

Patients enrolled had progressive CEA(+) tumors with metastatic liver lesions. Patients had received a median of three previous chemotherapy regimens, with a median of 2 months since their last chemotherapy regimen. Only 58% had metastatic disease limited to the liver. Vaccination commenced day 1 with biweekly boosters and split-course radiation (total 32 Gy) starting on day 21. Blood was collected at baseline and day 91 for immunological analysis.

RESULTS/CONCLUSION

A total of 12 patients were enrolled. There were no grade 3 or greater toxicities or grade 2 or greater hepatic toxicities. Median time on-study was 3 months, with the longest time on treatment being 5 months (n = 2). Immunological analysis was limited to two patients; neither showed an increase above baseline in CEA-specific T cells post-therapy. CEA/TRICOM vaccination in combination with low-dose radiation therapy is safe. There was limited evidence of activity in this patient population.

Generation of functional monocyte-derived fast dendritic cells suitable for clinical application in the absence of interleukin-6

To develop dendritic cells (DCs)-based immunotherapy for cancer patients, it is necessary to have a standardized, reproducible, fast, and easy to use protocol for in vitro generation of fully functional DCs. Recently, a new strategy was described for differentiation and maturation of human monocyte (Mo)-derived fast-DCs with full T cell stimulatory capacity within only 48-72 h of in vitro culture. Interleukin (IL)-6 plus tumour necrosis factor (TNF)-α, IL-1β, and prostaglandin (PG)-E(2) were used in this strategy to induce maturation of the generated DCs. The present study further modifies this strategy by excluding IL-6 from the cytokines cocktail used for DCs maturation. The results showed that maturation of fast-DCs without IL-6 did not significantly alter the morphology, phenotype and the yield of mature DCs (P > 0.05, compared with those generated with IL-6). Moreover, fast-DCs generated without IL-6 are functional antigen presenting cells, have the ability to induce tetanus toxoid-specific autologous T cell proliferation, and are suitable for gene delivery through adenoviral vector transduction as those generated with IL-6 (P > 0.05). In conclusion, the present study proves that fully mature and functional Mo-derived fast-DCs can be generated in vitro without adding IL-6, which not only reduces the number of required recombinant cytokines, but may also resemble DCs development in vivo more closely.

Drug or vaccine?: selecting the appropriate treatment for malignant glioma patients

Malignant gliomas are the most common and aggressive form of brain tumour. Current combinations of aggressive surgical resection, radiation therapy and chemotherapy regimens do not significantly improve long-term patient survival for these cancers. Therefore, investigative therapies including tumour vaccines have targeted this devastating condition. This article reviews evidence and data on chemotherapy and immunotherapy for a personalized medicine approach in order to enable physicians to select the appropriate treatment for glioma patients. Dendritic cell- and peptide-based therapy for gliomas seems to be safe and without major adverse effects. Gene-modified vaccines have also shown promise in the treatment of malignant gliomas. The concept of 'personalized medicine' is currently important in oncology treatment development. Using a personalized medicine approach, it may be necessary to evaluate the molecular genetic abnormalities in individual patient tumours, and such findings should be the mainstay of immunotherapeutic strategies designed for the individual patient.

Use of dentritic cells pulsed with HLA-A2-restricted MAGE-A1 peptide to generate cytotoxic T lymphocytes against malignant glioma

This study developed a novel approach of targeting malignant glioma with pMAGE-A1(278-286)-specific cytotoxic T lymphocytes (CTLs) induced from the peripheral blood mononuclear cells of healthy donors by multiple stimulations with human leukocyte antigen (HLA)-A2-restricted pMAGE-A1(278-286) peptide-pulsed dentritic cells. Cytotoxic assays were performed by the colorimetric CytoTox 96 assay to analyze cytotoxic activity of the induced CTLs against various target cells. The induced CTLs showed approximately 45% specific lysis against T2pMAGE-A1(278-286) (pMAGE-A1(278-286) peptide pulsed T2 cells) and U251 (HLA-A2(+), MAGE-A1(+)) at an effector:target ratio of 40:1, and approximately 5% cytolysis against T2pHIV, A172 (HLA-A2(-), MAGE-A1(+)), K562 and T2 cells without being pulsed with peptide at any effector:target ratio. The specific killing activity of the induced CTLs against T2pMAGE-A1(278-286) and U251 was much more obvious than in any other control group (P<0.05). The cytotoxic activity against the T2pMAGE-A1(278-286) and U251 was significantly eliminated by anti-HLA class I mAb W6/32. These results suggest that pMAGE-A1(278-286) epitope may serve as a surrogate tumor antigen target of specific immunotherapy for treating HLA-A2 patients with malignant glioma.

Dendritic cell vaccine in addition to FOLFIRI regimen improve antitumor effects through the inhibition of immunosuppressive cells in murine colorectal cancer model

Although chemotherapy is still one of the best treatments for most cancers, immunotherapies such as dendritic cell (DC) vaccines have emerged as an alternative protocol for destroying residual tumors. In this study, we investigated antitumor effects of the combined therapy using DC vaccine and irinotecan plus infusional 5-fluorouracil and leucovorin (FOLFIRI) which have been clinically used for the treatment of colorectal cancer. A maximum tolerated dose of FOLFIRI was preliminarily determined for MC38/CEA2 colorectal cancer model. Vaccination with DC expressing carcinoembryonic antigen (CEA) enhanced antitumor effect after FOLFIRI treatment. The combined therapy also increased CEA-specific Th1 and cytotoxic T-cell responses. Interestingly, although FOLFIRI treatment rather showed a rebound in the number of myeloid-derived suppressor cells (MDSC) and regulatory T-cells (Treg) after 14 days, additional DC vaccine could inhibit the rebound of these immunosuppressive cells. Furthermore, mice cured by the combined therapy showed antigen-specific T-cell responses and resistance against challenge of MC38/CEA2 compared with mice cured with FOLFIRI. These results demonstrated that DC vaccine in addition to FOLFIRI regimen could improve antitumor effects through the inhibition of immunosuppressive tumor environments in murine colorectal cancer model, and may provide knowledge useful for the design of chemo-immunotherapeutic strategies for the treatment of colorectal carcinoma in clinical trials.

Antitumor effects of murine bone marrow-derived dendritic cells infected with xenogeneic livin alpha recombinant adenoviral vectors against Lewis lung carcinoma

Transduction with recombinant, replication-defective adenoviral (rAd) vectors encoding a transgene is an efficient method for gene transfer into dendritic cells (DCs). Livin is a member of the inhibitor of apoptosis protein family. Lung cancer and many other tumors express livin at high levels; whereas, normal fully differentiated cells generally do not. Therefore, livin represents a tumor-specific target for cancer vaccine therapy. Self proteins like livin may not stimulate potent antitumor immune responses due to central immunologic tolerance. Small variations in protein sequence that may exist between homologous proteins of different species can break tolerance to the native antigen. To study immunogenicity of a xenogeneic livin protein, we constructed an recombinant adenoviral vectors containing the human livin alpha genes (rAd-hlivin alpha) and vaccinated C57BL/6 mice with mouse bone marrow dendritic cells (BMDCs) transfected with rAd-hlivin alpha gave rise to potent livin-specific cytotoxic T lymphocyte (CTL) capable of lysing Lewis lung carcinoma (LLC) cells. Moreover, vaccination of mice with rAd-hlivin alpha-transduced DCs (rAd-hlivin alpha DCs) induced a potent protective and therapeutic anti-tumor immunity to LLC in a subcutaneous model along with prolonged survival compared to mice vaccinated with control recombinant adenovirus-transduced DCs(rAd-c DCs) or DCs alone. Therefore, xenogeneic differences between human and murine sequences might be exploited to develop immunogenic tumor vaccines.

Efficient co-transduction of adenoviral vectors encoding carcinoembryonic antigen and survivin into dendritic cells by the CAR-TAT adaptor molecule enhance anti-tumor immunity in a murine colorectal cancer model

Because multiple tumor antigens, including carcinoembryonic antigen (CEA) and survivin (SVV), have been frequently observed in human colorectal cancer, we investigated whether the expression of both CEA and SVV by co-transduction of adenovirus vectors into dendritic cells (DCs) could improve anti-tumor immunity in a murine colorectal cancer model. The adaptor fusion protein of Coxsackie and adenovirus receptor and TAT-protein transduction domain (CAR-TAT) enhanced co-transduction of adenovirus vectors encoding CEA (AdCEA) and SVV (AdSVV) into DCs, and increased anti-tumor immunity. DCs expressing both CEA and SVV in the presence of CAR-TAT (DC-AdCEA/AdSVV+CAR-TAT) induced T-cell responses specific for CEA and SVV, and enhanced cytotoxic T-cell activity on MC38/CEA2 cells expressing CEA and SVV compared with DCs expressing either CEA or SVV alone. Particularly, DC-AdCEA/AdSVV+CAR-TAT induced higher number of CEA-specific IFN-gamma secreting T cells compared with DC-AdCEA+CAR-TAT. Vaccination with DC-AdCEA/AdSVV+CAR-TAT also more efficiently inhibited tumor growth compared with DCs expressing either CEA or SVV alone in therapeutic tumor models. These results suggest that efficient co-transduction of multiple adenovirus vectors by CAR-TAT could be used to develop various strategies for therapeutic DC vaccines.

A genetically engineered adenovirus vector targeted to CD40 mediates transduction of canine dendritic cells and promotes antigen-specific immune responses in vivo

Targeting viral vectors encoding tumor-associated antigens to dendritic cells (DCs) in vivo is likely to enhance the effectiveness of immunotherapeutic cancer vaccines. We have previously shown that genetic modification of adenovirus (Ad) 5 to incorporate CD40 ligand (CD40L) rather than native fiber allows selective transduction and activation of DCs in vitro. Here, we examine the capacity of this targeted vector to induce immune responses to the tumor antigen CEA in a stringent in vivo canine model. CD40-targeted Ad5 transduced canine DCs via the CD40-CD40L pathway in vitro, and following vaccination of healthy dogs, CD40-targeted Ad5 induced strong anti-CEA cellular and humoral responses. These data validate the canine model for future translational studies and suggest targeting of Ad5 vectors to CD40 for in vivo delivery of tumor antigens to DCs is a feasible approach for successful cancer therapy.

Improved therapeutic efficacy using vaccination with glioma lysate-pulsed dendritic cells combined with IP-10 in murine glioma

The purpose of the present study was to evaluate the therapeutic efficacy of glioma lysate-pulsed DCs in combination with plasmid DNA vector encoding the murine interferon-induced protein of 10kDa (IP-10 or CXCL10) gene. Mouse models of brain glioma (GL261) were treated with combining glioma lysate-pulsed DCs with direct intratumoral injection of a nonviral plasmid DNA vector encoding the murine IP-10 gene. The survival of mice bearing GL261 glioma was observed. Enzyme-linked immuno-spot assay was used to determine the frequency of brain-infiltrating lymphocytes (BILs) capable of responding to GL261. Cytolytic T lymphocyte (CTL) response was measured by cytotoxic assay, vessel density and tumor cell proliferation were observed by immunostaining, and tumor apoptosis was determined by TUNEL staining. The results revealed that the combination therapy groups showed more significantly enhanced anti-tumor activity, attraction of lymphocytes into tumor tissues, apoptosis of tumor cells, and reduced neovascularization, cell proliferation, and developed a strong CTL response in these mice. In summary, the therapy of glioma lysate-pulsed DCs combined with the IP-10 gene has significant synergistic effect against glioma.

Gene therapy as an adjuvant treatment for malignant gliomas: from bench to bedside

Malignant brain tumors, including high-grade gliomas, are among the most lethal of all cancers. Despite considerable advances, including multi-modality treatments with surgery, radiotherapy, and chemotherapy, the overall prognosis for patients with this disease remains dismal. Currently available treatments necessitate the development of more effective tumor-selective therapies. The use of gene therapy for brain tumor therapy is promising as it can be delivered in situ and selectively targets brain tumor cells while sparing the adjacent normal brain tissue. In this article, we summarize the laboratory and clinical work using viral, cell-based, and synthetic vectors, as well as other strategies focused on potentiate gene delivery. Although tangible results on patients' survival remains to be further documented, significant advances in therapeutic gene transfer strategies have been made. The enthusiasm of this progress needs to be tempered by the realistic assessment of the challenges needed to be overcome. Finally, as the field of gene delivery progresses, advances must be made in identifying genes and proteins key to the treatment of malignant gliomas. Due to the great heterogeneity of malignant glioma cells, only approaches combining different strategies may be ultimately successful in defeating this disease.

Modification of CEA with both CRT and TAT PTD induces potent anti-tumor immune responses in RNA-pulsed DC vaccination

Carcinoembryonic antigen (CEA) is expressed on human colon carcinomas, is well characterized, and continues to be a promising target for cancer immunotherapy in humans. To enhance the immunogenecity of CEA, we developed a fusion gene (CRT-TAT-DeltaCEA) of the TAT protein transduction domain (PTD) and calreticulin (CRT) with human CEA devoid of its signal sequences (DeltaCEA) and evaluated anti-tumor immunity using RNA-pulsed dendritic cell (DC) vaccination. Mice vaccinated with DC by electroporation with mRNA encoding TAT-DeltaCEA (DC/TAT-DeltaCEA) and CRT-DeltaCEA (DC/CRT-DeltaCEA) had enhanced induction of tumor-specific cytotoxic T lymphocyte (CTL) and increased numbers of IFN-gamma-secreting T cells by ELISPOT, as compared to mice vaccinated with DC/DeltaCEA. DC/CRT-DeltaCEA and DC/TAT-DeltaCEA vaccines preferentially stimulated CD4+ and CD8+ T cells, respectively. The DC vaccine by electroporation with mRNA encoding CRT-TAT-DeltaCEA (DC/CRT-TAT-DeltaCEA) enhanced both CD4+ and CD8+ T cells. DC/CRT-TAT-DeltaCEA had the additional effects of CRT and TAT PTD and enhanced the anti-tumor effect against CEA-expressing tumors compared to DC/CRT-DeltaCEA or DC/TAT-DeltaCEA. These findings suggest that modification of CEA with both CRT and TAT PTD induces potent anti-tumor immune responses in RNA-pulsed DC vaccination and may be a useful approach for DC-based immunotherapy.

HLA-A2-restricted cytotoxic T lymphocyte epitopes from human heparanase as novel targets for broad-spectrum tumor immunotherapy

Peptide vaccination for cancer immunotherapy requires identification of peptide epitopes derived from antigenic proteins associated with tumors. Heparanase (Hpa) is broadly expressed in various advanced tumors and seems to be an attractive new tumor-associated antigen. The present study was designed to predict and identify HLA-A2-restricted cytotoxic T lymphocyte (CTL) epitopes in the protein of human Hpa. For this purpose, HLA-A2-restricted CTL epitopes were identified using the following four-step procedure: 1) a computer-based epitope prediction from the amino acid sequence of human Hpa, 2) a peptide-binding assay to determine the affinity of the predicted protein with the HLA-A2 molecule, 3) stimulation of the primary T-cell response against the predicted peptides in vitro, and 4) testing of the induced CTLs toward different kinds of carcinoma cells expressing Hpa antigens and/or HLA-A2. The results demonstrated that, of the tested peptides, effectors induced by peptides of human Hpa containing residues 525-533 (PAFSYSFFV, Hpa525), 277-285 (KMLKSFLKA, Hpa277), and 405-413 (WLSLLFKKL, Hpa405) could effectively lyse various tumor cell lines that were Hpa-positive and HLA-A2-matched. We also found that these peptide-specific CTLs could not lyse autologous lymphocytes with low Hpa activity. Further study revealed that Hpa525, Hpa277, and Hpa405 peptides increased the frequency of IFN-gamma-producing T cells compared to a negative peptide. Our results suggest that Hpa525, Hpa277, and Hpa405 peptides are new HLA-A2-restricted CTL epitopes capable of inducing Hpa-specific CTLs in vitro. Because Hpa is expressed in most advanced malignant tumors, Hpa525, Hpa277, and Hpa405 peptide-based vaccines may be useful for the immunotherapy for patients with advanced tumors.

Efficient generation of survivin-specific cytotoxic T lymphocytes from healthy persons in vitro: quantitative and qualitative effects of CD4+ T cells

For the adoptive immunotherapy and the study of cytotoxic T lymphocytes (CTLs) in human, efficient in vitro generation of CTLs is needed. However, it is still difficult to induce T cells specific for naïve antigens in vitro even though dendritic cells (DCs) as potent APCs are used. In this study, we investigated quantitative and qualitative effects of CD4+ T cells during in vitro stimulation of CD8+ T cells from healthy donors using DCs transduced with adenovirus vector expressing human survivin (Adv-survivin). CTLs were not efficiently induced in the absence of CD4+ T cells or in CD25+ depleted CD4+ T cells. When the ratio of CD4+:CD8+ T cells was quantitatively decreased from 2:1 to 1:2, proliferation of CTLs specific for survivin was gradually increased. Because DCs pulsed with HCMV pp65 protein could activate CD4+ T cells to secrete Th1 cytokines, the use of pp65 protein as an adjuvant induced higher numbers and frequencies of CTLs. Furthermore, Th1 conditioning of CD4+ T cells augmented this generation of CTLs. These results suggest that both quantitative and qualitative modulation of CD4+ T cells including the number and Th1 polarization may be required for the efficient induction of CTLs specific for tumor antigens in vitro.

Co-administration of carcinoembryonic antigen and HIV TAT fusion protein with CpG-oligodeoxynucleotide induces potent antitumor immunity

Although dendritic cells (DC) have been well demonstrated as a strong cellular adjuvant for a tumor vaccine, there are several limitations for clinical application. A protein-based vaccine using a potent adjuvant is an appealing approach for tumor antigen-specific immunotherapy because of their simplicity, safety, efficacy and capacity for repeated administration. CpG-oligodeoxynucleotides (ODN) have been used as adjuvants to stimulate innate and adaptive immune responses for cancer treatment. The authors evaluated the adjuvant effects of CpG-ODN in a vaccine incorporating recombinant fusion protein of the HIV TAT PTD domain and carcinoembryonic antigen (TAT-CEA). Mice vaccinated with TAT-CEA and CpG-ODN (TAT-CEA + CpG) showed enhanced CEA-specific immunity, including cytotoxic T-lymphocytes (CTL) activity and interferon (IFN)-gamma secreting T cells compared with CEA and CpG-ODN (CEA + CpG) or TAT-CEA vaccination alone. Vaccination with TAT-CEA + CpG elicited Th1-based responses, as indicated by the higher ratio of immunoglobulin (Ig)G2a antibody/IgG1 antibodies specific for CEA. The survival rate was significantly increased after vaccination with TAT-CEA + CpG in a tumor model using MC38/CEA2. Furthermore, the TAT-CEA +/- CpG vaccine groups showed similar antitumor immunity to the CEA peptide-pulsed DC (CEA peptide/DC) vaccine groups. These data suggest that coadministration of TAT fusion protein with CpG-ODN may serve as a potential formulation for enhancing antitumor activity.

H-2Kb-restricted CTL epitopes from mouse heparanase elicit an antitumor immune response in vivo

The identification of CTL epitopes from tumor antigens is very important for the development of peptide-based, cancer-specific immunotherapy. Heparanase is broadly expressed in various advanced tumors and can serve as a universal tumor-associated antigen. Although several epitopes of heparanase antigen are known in humans, the corresponding knowledge in mice is still rather limited. The present study was designed to predict and identify the CTL epitopes in the mouse heparanase protein. For this purpose, H-2K(b)-restricted CTL epitopes were identified by using the following four-step procedure: (a) a computer-based epitope prediction from the amino acid sequence of mouse heparanase, (b) a peptide-binding assay to determine the affinity of the predicted epitopes with the H-2K(b) molecule, (c) the testing of the induction of CTLs toward various carcinoma cells expressing heparanase antigens and H-2K(b), and (d) the induction of immunoprotection and immunotherapy in vivo. The results showed that, of the tested peptides, effectors induced by peptides of mouse heparanase at residue positions 398 to 405 (LSLLFKKL; mHpa398) and 519 to 526 (FSYGFFVI; mHpa519) lysed three kinds of carcinoma cells expressing both heparanase and H-2K(b) (B16 melanoma cells, EL-4 lymphoma cells, and Lewis lung cancer cells). In vivo experiments indicated that mHpa398 and mHpa519 peptides offered the possibility of not only immunizing against tumors but also treating tumor-bearing hosts successfully. Our results suggest that the mHpa398 and mHpa519 peptides are novel H-2K(b)-restricted CTL epitopes capable of inducing heparanase-specific CTLs in vitro and in vivo. These epitopes may serve as valuable tools for the preclinical evaluation of vaccination strategies.

Introduction of functional chimeric E/L-selectin by RNA electroporation to target dendritic cells from blood to lymph nodes

BACKGROUND

Inefficient migration of dendritic cells (DC) to regional lymph nodes (LN) upon intracutaneous injection is a major obstacle for effective DC vaccination. Intravenous vaccination is unfavorable, because DC cannot migrate directly from the blood into LN.

METHODS

To enable human monocyte-derived (mo)DC to enter LN directly from the blood, we manipulated them by RNA electroporation to express a human chimeric E/L-selectin (CD62E/CD62L) protein, which binds to peripheral node addressin expressed on high endothelial venules.

RESULTS

Transfection efficiency exceeded 95%, and high E/L-selectin surface expression was detected for >48 h. E/L-selectin RNA-transfected DC displayed an identical mature DC phenotype as mock-transfected DC. Furthermore, E/L-selectin-transfected DC maintained their normal CCR7-mediated migration capacity, and their ability to prime and expand functional cytotoxic T cells recognizing MelanA. Most importantly, E/L-selectin-RNA-transfected DC gained the capability to attach to and roll on sialyl-Lewis(X) in vitro.

OUTLOOK

The presented strategy can be readily translated into the clinic, as it involves no stable genetic manipulation or viral transformation, and allows targeting of a large number of LN.

Dendritic cells reconstituted with a human heparanase gene induce potent cytotoxic T-cell responses against gastric tumor cells in vitro

BACKGROUND AND AIMS

Dendritic cell-based tumor vaccination is a promising approach in the treatment of cancer. Strategies to modify dendritic cells (DCs) with tumor-associated antigens (TAAs) can elicit specific immune responses against tumors. Heparanase is overexpressed in gastric cancer, especially in invasive and metastatic cells, but is downregulated in differential normal tissue. Therefore, heparanase is a potential target in immunotherapy for patients with advanced gastric cancer who are not candidates for surgery. The present paper was designed to investigate the immune response of a heparanase gene-modified DC-based vaccine against gastric cancer cell lines in vitro.

METHODS

DCs from peripheral blood mononuclear cells of healthy HLA-A2-positive donors were transfected with recombinant adenovirus containing the full-length cDNA of heparanase (rAd-Hpa) to generate heparanase gene-modified DC vaccine. T lymphocytes from the same donors were repeatedly activated by genetically modified DC vaccine to generate heparanase-specific cytotoxicity T lymphocytes (CTLs). CTL-mediated cell lysis of gastric cancer cells lines (KATO-III and SGC-7901) was analyzed in vitro by a standard (51)Cr releasing assay. IFN-gamma secretion was measured by ELISA in heparanase-specific CTLs cocultured with those gastric cancer cell lines.

RESULTS

Our results showed that the expression of heparanase in DCs transfected with rAd-Hpa was significantly increased. Furthermore, DCs transfected with rAd-Hpa could induce heparanase-specific CTLs against HLA-matched and heparanase-positive gastric cancer cells in vitro, while there were no killing effects on autologous lymphocytes. Meanwhile, these rAd-Hpa-modified DCs could increase IFN-gamma secretion of effector cells when cocultured with KATO-III cells.

CONCLUSIONS

These findings demonstrate for the first time that the transduction of DCs with rAd-Hpa can induce CTLs that specifically lyse heparanase-positive gastric cancer cells and increase IFN-gamma secretion in an MHC-restricted fashion. Heparanase gene-modified DC vaccine offers a great opportunity for immunotherapy in patients with advanced gastric cancer and possibly also with other malignancies.

In vitro anti-tumor immune response induced by dendritic cells transfected with hTERT recombinant adenovirus

Transduction with recombinant, replication-defective adenoviral (Ad) vectors encoding a transgene is an efficient method for gene transfer into human dendritic cells (DC). Several studies have demonstrated that epitopes of the human telomerase reverse transcriptase gene (hTERT) can produce CTLs specific for malignant tumors. In this study, we constructed an hTERT recombinant adenovirus (rAd-hTERT) using DNA recombination. We found that human dendritic cells transduced with rAd-hTERT could effectively induce hTERT-specific cytotoxic T lymphocytes (CTLs) in vitro against various tumor cell lines, which were hTERT-positive and HLA-A2 matched. We also found that these hTERT-specific CTLs could not lyse autologous lymphocytes with low telomerase activity. Further studies revealed that rAd-hTERT transduced DCs could increase secretion of IFN-gamma by effector cells when they were co-cultured with hTERT-positive and HLA-A2 matched tumor cell lines. These data suggest that an hTERT vaccine can induce anti-tumor immunity against various tumor cells expressing hTERT in a HLA-A2-restricted fashion in vitro. The transduction of DCs with rAd-hTERT offers a great opportunity in cancer immunotherapy.

Enhancement of anti-tumor immunity specific to murine glioma by vaccination with tumor cell lysate-pulsed dendritic cells engineered to produce interleukin-12

AIM

The aim of this study was to develop an immunotherapy specific to a malignant glioma by examining the efficacy of glioma tumor-specific cytotoxic T lymphocytes (CTL) as well as the anti-tumor immunity by vaccination with dendritic cells (DC) engineered to express murine IL-12 using adenovirus-mediated gene transfer and pulsed with a GL26 glioma cell lysate (AdVIL-12/DC+GL26) was investigated. EXPERIMENT1: For measuring CTL activity, splenocytes were harvested from the mice immunized with AdVIL-12/DC+GL26 and restimulated with syngeneic GL26 for 7 days. The frequencies of antigen-specific cytokine-secreting T cell were determined with mIFN-gamma ELISPOT. The cytotoxicity of CTL was assessed in a standard 51Cr-release assay. For the protective study in the subcutaneous tumor model, the mice were vaccinated subcutaneously (s.c) with 1x10(6) AdVIL-12/DC+GL26 in the right flanks on day -21, -14 and -7. On day 7, the mice were challenged with 1x10(6) GL26 tumor cells in the shaved left flank. For a protective study in the intracranial tumor model, the mice were vaccinated with 1x10(6) AdVIL-12/DC+GL26 s.c in the right flanks on days -21, -14 and -7. Fresh 1x10(4) GL26 cells were inoculated into the brain on day 0. To prove a therapeutic benefit in established tumors, subcutaneous or intracranial GL26 tumor-bearing mice were vaccinated s.c with 1x10(6) AdVIL-12/DC+GL26 on day 5, 12 and 19 after tumor cell inoculation.

RESULTS

Splenocytes from the mice vaccinated with the AdVIL-12/DC+GL26 showed enhanced induction of tumor-specific CTL and increased numbers of IFN-gamma: secreting T cells by ELISPOT. Moreover, vaccination of AdVIL-12/DC+GL26 enhanced the induction of anti-tumor immunity in both the subcutaneous and intracranial tumor models.

CONCLUSIONS

These preclinical model results suggest that DC engineered to express IL-12 and pulsed with a tumor lysate could be used in a possible immunotherapeutic strategy for malignant glioma.

Viral Vaccines for Cancer Immunotherapy

The understanding that tumor cells can be recognized and eliminated by the immune system has led to intense interest in the development of cancer vaccines. Viruses are naturally occurring agents that cause human disease but have the potential to prevent disease when attenuated forms or subunits are used as vaccines before exposure. A large number of viruses have been engineered as attenuated vaccines for the expression of tumor antigens, immunomodulatory molecules, and as vehicles for direct destruction of tumor cells or expression of highly specific gene products. This article focuses on the major viruses that are under development as cancer vaccines, including the poxviruses, adenoviruses, adeno-associated viruses, herpesviruses, retroviruses, and lentiviruses. The biology supporting these viruses as vaccines is reviewed and clinical progress is reported.

Adoptive transfer of Epstein-Barr virus-specific cytotoxic T-lymphocytes for the treatment of angiocentric lymphomas

Angiocentric lymphoma, known as natural killer (NK)/T-cell non-Hodgkin's lymphoma, has been reported to be associated with the Epstein-Barr virus (EBV). We performed adoptive transfer of EBV-specific polyclonal T-cell lines in 3 patients with extranodal NK/T-cell lymphoma, nasal type, and evaluated the treatment for safety, immunologic reconstitution, and clinical outcomes. The tissue samples collected from the 3 patients were confirmed by polymerase chain reaction analysis to be EBV positive. In the cases of the first and second patients, EBV-transformed B-lymphoblastoid cell lines (LCLs) and T-cell lines were generated from peripheral lymphocytes of HLA-matched sibling donors. The third patient's T-cell lines were induced with autologous lymphocytes. Polyclonal T-cell infusion was carried out after high-dose radiotherapy because active relapsed disease remained in all of the patients. The first patient received 4 weekly infusions of 2 3 10(7) cells/m(2), and the second and third patients underwent treatment with 2 cycles of infusions of the same dosage. All T-cell lines showed >60% NK activity, cytotoxic T-lymphocyte (CTL) responses of >40% against autologous LCLs, and no CTL activity against patient-derived lymphoblasts. The level of cytotoxicity increased substantially in all patients after cell infusion. The 2 patients who received T-cell therapy twice had stabilized disease for more than 3 years. These safe treatments exhibited no severe inflammatory response, and no serious toxicity developed during T-cell therapy. Our findings demonstrate that adoptively transferred cells may provide reconstitution of EBV-specific CTL responses in patients with active relapsed angiocentric lymphoma. These results provide a rationale for the immunotherapy of angiocentric lymphoma.

Transduction with a fiber-modified adenoviral vector is superior to non-viral nucleofection for expressing tumor-associated Ag mucin-1 in human DC

BACKGROUND

DC-presenting tumor Ag are currently being developed to be used as a vaccine in human cancer immunotherapy. To increase the chances for successful therapy it is important to deliver full-length tumor Ag instead of loading single peptides. Methodologically, several recombinant DNA delivery techniques have been used.

METHODS

In this study we compared nucleofection, an optimized form of electroporation, and adenoviral transduction regarding their efficiency to transduce human monocyte-derived (Mo-) DC in vitro. Expression of the tumor-associated Ag mucin-1 (MUC1) after adenoviral transduction (rAd5Fib35-MUC1) was determined using two MAb.

RESULTS

We showed that the viability of cells and percentage of green fluorescent protein (GFP)-positive cells after transduction with a fiber-modified adenoviral vector (rAd5F35-GFP) was much higher than after nucleofection. Furthermore, phenotype and function of DC were not impaired by infection with adenovirus particles. Cells matured normally; up-regulation of CD40, CD80, CD83, CD86 and HLA-DR was not affected by adenoviral transduction. The capacity to stimulate naive T-cell proliferation was preserved and no change in IL-10 production was observed. Production of IL-12 increased up to 500-fold upon adenoviral transduction, considered to contribute positively to an anti-tumor immune response. Non-transduced mature DC expressed low levels of endogenous MUC1. After transduction with the rAd5F35-MUC1 adenoviral vector, a 100-fold increase in MUC1 expression by DC was observed.

DISCUSSION

The use of the fiber-modified adenoviral vector presented here may therefore be favorable compared with non-viral gene delivery systems for DC that will be used in cancer immunotherapy.

Adenovirus as vehicle for anticancer genetic immunotherapy

Adenoviruses (Ads) are in the forefront of genetic immunization methods being developed against cancer. Their ability to elicit an effective immune response against tumor-associated antigens has been demonstrated in many model systems. Several clinical trials, which use Ad as vehicle for immunization, are already in progress. Preclinical studies have also demonstrated the efficacy of combining Ad-mediated immunization with adjuvants such as chemotherapeutic agents and cytokines. Issues related to sero-prevalence and safety of Ads, however, continue to pose a challenge and need to be addressed.

Antitumour activity mediated by CD4+ cytotoxic T lymphocytes against MHC class II-negative mouse hepatocellular carcinoma induced by dendritic cell vaccine and interleukin-12

When BALA/c mice with BNL hepatocellular carcinoma (HCC) were treated with dendritic cells fused with BNL cells (DC/BNL) and recombinant murine interleukin (IL)-12, tumour development was significantly suppressed, whereas treatment with either DC/BNL or IL-12 alone did not show a tumour-suppressive effect. Antitumour activity induced by DC/BNL + IL-12 was abrogated by depletion of CD4+ T cells, but not by depletion of CD8+ T cells or natural killer cells. Splenic CD4+ T cells and CD8+ T cells from DC/BNL-treated mice showed cytotoxic activity against BNL cells after 3 days of incubation with DC/BNL, although BNL cells do not express major histocompatibility complex (MHC) class II molecules even after treatment with interferon (INF)-gamma. Furthermore, CD4+ T cells killed syngeneic-irrelevant CT26 cells and even allogeneic Hepa1-6 cells. This cytotoxicity was blocked by concanamycin A, but not by an anti-Fas ligand (FasL) monoclonal antibody, indicating that cytotoxic activity was mediated by perforin. Immunofluorescence microscopy demonstrated that abundant CD4+ T cells and MHC class II-positive macrophages, but not CD8(+) T cells, had infiltrated tumour tissue in mice treated with DC/BNL + IL-12. Flow cytometric analysis of tumour-infiltrating cells in mice treated with DC/BNL + IL-12 showed increases in CD4+ T cells and MHC class II+ CD11b+ cells but not in CD8+ T cells or MHC class I+ CD11b+ cells. Our results suggest that, in BNL-bearing mice treated with DC/BNL + IL-12, tumour macrophages activated by INF-gamma produced by IL-12-stimulated T cells might present BNL tumour antigens and activate DC/BNL-primed CD4+ cytotoxic T lymphocytes (CTLs) in a MHC class II-dependent manner, leading to perforin-mediated bystander killing of neighbouring MHC class II-negative tumour cells.