Autologous, allogeneic tumor cells or genetically engineered cells as cancer vaccine against melanoma

Effective tumor immunity to melanoma mediated by B16F10 cancer stem cell vaccine

Although tumor vaccines have been considered a promising immunotherapy approach, therapeutic tumor vaccines are mostly disappointing in the clinic due to vaccine weak immunogenicity. Cancer stem cells (CSCs) may broaden the antigenic breadth and effectively induce the immune responses against autologous cancer cells. Here we report on the development of the B16F10 CD133⁺CD44⁺CSCs (B16F10 CSCs) vaccine to induce tumor immunity to melanoma in mice. Efficacy of against melanoma was evaluated by analysis of tumor growth and mouse survival. Immunogenicity was assessed by ELISA and flow cytometric assays, including serum cytokines, cytotoxic activity of NK cells and splenocytes in the immunized mice. The results showed that the B16F10 CSC vaccine resulted in tumor shrinkage and mouse lifespan extension. The cytotoxic activity and IFN-γ level were significantly increased in mice immunized with B16F10 CSC vaccine compared with the mice immunized with control vaccines. Additionally, New York esophageal squamous cell carcinoma-1, an efficient tumor associated antigen over-expressed by B16F10 CSCs, was markedly reduced in expression in melanoma tissue, suggesting decrease of CSC subpopulation due to B16F10 CSC vaccination. Collectively, the findings may represent a new powerful approach for treatment of melanoma by B16F10 CSC vaccination.

ESAT-6-gpi DNA vaccine augmented the specific antitumour efficacy induced by the tumour vaccine B16F10-ESAT-6-gpi/IL-21 in a mouse model

In this study, we hypothesized that the mice immunized with the glycosylphosphatidylinositol (GPI) anchored 6-kDa early-secreted antigenic target (ESAT-6) DNA vaccine (ESAT-6-gpi) and the tumour vaccine B16F10-ESAT-6-gpi/IL-21 might significantly enhance immune responses and antimelanoma efficacy. Our experimental results indicated that the anti-ESAT-6 antibody induced by the DNA vaccine ESAT-6-gpi bound ESAT-6 to the surface of tumour vaccine to activate a complement classical pathway and resulted in the B16F10 tumour cell lysis and apoptosis, which served as a potential trigger for breaking melanomatous immune tolerance to elicit an initiation of natural antimelanoma immunity. Our innovative approach of using the DNA vaccine ESAT-6-gpi priming and the tumour vaccine B16F10-ESAT-6-gpi/IL-21 boosting induced strong antimelanoma immunity that inhibited melanomatous growth. These findings highlighted the DNA vaccine ESAT-6-gpi as an immune enhancer to augment the immune efficacy of the tumour vaccine B16F10-ESAT -6-gpi/IL-21 against melanoma in a mouse model.

Chemokine-based immunotherapy: delivery systems and combination therapies

A major role of chemokines is to mediate leukocyte migration through interaction with G-protein-coupled receptors. Various delivery systems have been developed to utilize the chemokine properties for combating disease. Viral and mutant viral vectors expressing chemokines, genetically modified dendritic cells with chemokine or chemokine receptors, engineered chemokine-expressing tumor cells and pDNA encoding chemokines are among these methods. Another approach for inducing a targeted immune response is fusion of a targeting antibody or antibody fragment to a chemokine. In addition, chemokines induce more effective antitumor immunity when used as adjuvants. In this regard, chemokines are codelivered along with antigens or fused as a targeting unit with antigenic moieties. In this review, several chemokines with their role in inducing immune response against different diseases are discussed, with a major emphasis on cancer.

Thymic stromal lymphopoietin plays an adjuvant role in BCG-mediated CD8(+) cytotoxic T cell responses through dendritic cell activation

Although Bacillus Calmette-Guérin (BCG) has historically emerged as a potent adjuvant in cancer immunization through dendritic cell (DC) activation, the efficacy of its antitumor effect has been limited. Therefore, the strategy of adjuvant therapy using BCG needs to be improved by adding enhancers. Here we found that thymic stromal lymphopoietin (TSLP) acts as an enhancer for the BCG-mediated antitumor effect. While BCG-stimulated DCs induced CD8(+) T cell production of IFN-gamma without strong cell expansion, TSLP-stimulated DCs induced robust CD8(+) T cell expansion without high quantities of IFN-gamma production. Notably, DCs stimulated with both BCG and TSLP induced robust expansion of CD8(+) T cells that produced a large amount of IFN-gamma with a potent cytolytic activity related to granzyme B expression. Our data suggest that TSLP is a good adjuvant to enhance the BCG-mediated cytotoxic T cell effect through DC activation, and provide a functional basis for a novel strategy for antitumor immune-based therapy.

Dendritic cell preparation for immunotherapeutic interventions

Much effort has been made over the last decade to use dendritic cells (DCs) in vaccines to induce specific antitumor immune responses. However, the great hope provided by in vitro and in vivo preclinical investigations was not translated to the clinic in terms of clinical efficacy. Thus, one of the challenges resides in optimizing DC-based therapy to give maximum clinical efficacy while using manufacturing processes that enable quality control and scale-up of consistent products. In this article, we review DC biology and the DC-based clinical trials performed to date and focus on the DC maturation status compatible with the goals of cancer immunotherapy. We also highlight the different approaches used in these clinical studies, such as the DC types or subtypes used and their preparation. Finally, we discuss the immunological and clinical outcomes in treated patients, with emphasis on the strategies that could be used to improve DC-based vaccination.

Virotherapy with a type 2 herpes simplex virus-derived oncolytic virus induces potent antitumor immunity against neuroblastoma

PURPOSE

We recently constructed an oncolytic virus from type 2 herpes simplex virus (HSV-2) that selectively targets and kills tumor cells with an activated Ras signaling pathway. Designated FusOn-H2, this virus has shown several discrete killing mechanisms. Here, we evaluated the antitumor immune responses after FusOn-H2-mediated virotherapy in a syngeneic murine neuroblastoma model.

EXPERIMENTAL DESIGN

We directly injected FusOn-H2 into established tumors and then measured its antitumor effect and the accompanying tumor-specific immune responses. Several oncolytic HSVs constructed from HSV-1 were included in the same experiments for comparisons.

RESULTS

Our data show that tumor destruction by FusOn-H2 in vivo induces potent antitumor immune responses in this syngeneic neuroblastoma model. The elicited cellular immunity not only eradicated neuroblastoma cells in vitro but also inhibited the growth of tumors at sites distant from the virus injection site. Moreover, adoptive transfer of splenocytes from mice receiving virotherapy to naïve mice resulted in a measurable antitumor effect.

CONCLUSION

We conclude that the ability of FusOn-H2 to induce tumor-specific cellular immunity expands the oncolytic repertoire of this virus and increases the likelihood that its use in patients would produce significant therapeutic benefits.

Potential side effects of dendritic cells pulsed with allogenic melanoma cell lysate in mice

An attempt has been made to investigate the toxicity of cancer immunotherapy based on the dendritic cells pulsed with lysate of allogenic melanoma cell, DM401. Dendritic cells pulsed with lysate of clone M3 were subcutaneously administered once a week eight times to C57BL/6 mice at 0, 2.5, 5, and 10 x 10(7) cells/kg. No changes attributable to the administration were observed in clinical signs and food and water consumption. The administration induced slight increases in body weights, white blood cells, total protein, total cholesterol, triglyceride, phospholipids, and absolute spleen weights, but a slight decrease in albumin/globulin ratio. Microscopic examinations revealed the infiltration of inflammatory cells in the lung, mainly in the pulmonary arteriole, in which the tunica media thickened, and in the pulmonary alveoli and alveolar space. Thickened tunica media of pulmonary arteriole was observed in both males and females at all selected doses. In addition, the subcutis at the test substance-application site showed inflammation and fibrosis. In conclusion, lung is a target organ of DM401, and most of the changes including the findings in lung are considered as the immunomodulatory functions of dendritic cells.

Enhanced immune responses induced by vaccine using Sendai virosomes as carrier

Sendai virosomes can deliver encapsulated contents into the cytoplasm directly in a virus fusion-dependent manner. In this paper, Sendai virosomes-formulated melanoma vaccine was constructed and its anti-tumor effects were investigated. The melanoma vaccine was prepared by encapsulating mixture antigen into the Sendai virosomes. The antigen, mixture proteins were extracted from B(16) melanoma cells. The cytotoxic T lymphocyte (CTL) response level was evaluated by (51)Cr release method, and the change of CD4(+) and CD8(+) expression as well as the concentration of IgG in serum of immunized mice was measured. The results showed that Sendai virosomes-formulated melanoma vaccine can effectively elicit not only systemic immune response but also strong CTL response. Sendai virosomes can be used as an effective vector for use in anti-tumor vaccine therapy.

Immunization with murine breast cancer cells treated with antisense oligodeoxynucleotides to type I insulin-like growth factor receptor induced an antitumoral effect mediated by a CD8+ response involving Fas/Fas ligand cytotoxic pathway

We have demonstrated that in vivo administration of phosphorothioate antisense oligodeoxynucleotides (AS[S]ODNs) to type I insulin-like growth factor receptor (IGF-IR) mRNA resulted in inhibition of C4HD breast cancer growth in BALB/c mice. The present study focused on whether in vivo administration of C4HD tumor cells pretreated with IGF-IR AS[S]ODN and irradiated could provide protection against C4HD wild-type tumor challenge and also on elucidating the mechanism mediating this effect. Our results showed that mice immunized with IGF-IR AS[S]ODN-treated C4HD cells experienced a growth inhibition of 53.4%, 61.6%, and 60.2% when compared with PBS-treated mice, wild-type C4HD cell-injected mice, or phosphorothioate sense oligodeoxynucleotide-treated C4HD cell-injected mice, respectively. The protective effect was C4HD-specific, because no cross-protection was observed against other syngeneic mammary tumor lines. The lack of protection against tumor formation in nude mice indicated that T cells were involved in the antitumoral response. Furthermore, cytotoxicity and splenocyte proliferation assays demonstrated that a cellular CD8(+)-dependent immune response, acting through the Fas/Fas ligand death pathway, could be mediating the antitumor effect induced by immunization with AS[S]ODN-treated cells. Immunization also induced splenocytes to produce Ag-dependent IFN-gamma, indicating the presence of a type 1 response. We demonstrated for the first time that IGF-IR AS[S]ODN treatment of breast cancer cells induced expression of CD86 and heat shock protein 70 molecules, both involved in the induction of the immunogenic phenotype. Immunization with these tumor immunogens imparted protection against parental tumor growth through activation of a specific immune response.

Lung cancer immunotherapy

Recent insights into anti-tumor immunotherapy have led to a wave of clinical trials involving immunotherapy for lung cancer. Vaccines have evolved from nonspecific immune stimulants, like Bacillus Calmette-Guerin (BCG), to much more specific and potent strategies, some of which generate active immune responses against tumor-associated antigens. Understanding the mechanisms of anti-tumor immunity and identifying target antigens will likely improve these therapeutic strategies and provide them with a niche in the future of lung cancer therapy.

CpG immunostimulatory oligodeoxynucleotide 1826 enhances antitumor effect of interleukin 12 gene-modified tumor vaccine in a melanoma model in mice

PURPOSE

The effectiveness of interleukin (IL)-12-secreting tumor vaccines in the treatment of mouse tumors could be enhanced by concurrent application of cytokines and costimulatory molecules. We investigated the therapeutic potential of IL-12 gene-transduced melanoma vaccine in combination with CpG immunostimulatory oligodeoxynucleotide (ODN) 1826, an adjuvant known to favor development of Th1-biased immune response, in a B78-H1 (B78) melanoma model in mice.

EXPERIMENTAL DESIGN

Mice injected with B78 melanoma cells were treated with irradiated IL-12 gene-transduced B78 cells [B78/IL-12(X)] and/or ODN 1826. Mechanisms responsible for the antitumor effects of the treatment were investigated using fluorescence-activated cell sorter analysis, a standard (51)Cr releasing assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and ELISA.

RESULTS

Single injection of B78/IL-12(X) cells had no effect on tumor growth, whereas seven consecutive daily injections of ODN 1826 markedly inhibited tumor progression with occasional curative effects. When used in combination, B78/IL-12(X) cells and ODN 1826 caused additional tumor growth reduction and eradication of tumors in 62% of treated mice. The combined treatment activated local inflammatory response against tumor but also induced systemic antitumor immunity. In vitro studies have shown that when used together, B78/IL-12(X) cells and ODN 1826 induced a potent Th1 response and suggested the role of IFN-gamma in activation of the host immune response. The antitumor effects in double-treated mice were accompanied by the development of cytotoxic effectors in the spleen and activation of macrophages.

CONCLUSIONS

The results provided the evidence that the combination of IL-12 gene-modified melanoma vaccine and ODN 1826 induces synergistically systemic and local antitumor immunity.

Destruction of nonimmunogenic mammary tumor cells by a fusogenic oncolytic herpes simplex virus induces potent antitumor immunity

In principle, destruction of tumor cells in vivo by oncolytic agents would release the entire repertoire of tumor antigens in their natural forms, leading to effective antitumor immunity. This goal has been elusive despite extensive testing of numerous strategies. We developed a doubly fusogenic oncolytic herpes simplex virus (Synco-2D) that kills tumor cells by a unique dual mechanism combining direct cytolysis with syncytial formation induced by cell membrane fusion. A single intratumor injection of Synco-2D induced strong antitumor immunity against an otherwise nonimmunogenic murine mammary tumor growing in immune-competent mice. CD8+ T cells were the primary mediators of immunity, contributing to the destruction of both primary and metastatic tumors. We conclude that the fusogenic capacity of Synco-2D enables it to elicit antitumor immunity exceeding that induced by more conventional oncolytic viruses.

Colorectal cancer vaccines: principles, results, and perspectives

In the search for novel therapeutic approaches to treat patients with colorectal carcinoma, anticancer vaccination holds promise. A large body of preclinical and clinical evidence has demonstrated that the immune system can be polarized against malignant cells by means of several active specific immunotherapy strategies. Although no vaccination regimen can be currently recommended outside clinical trials, tumor response and immunologic findings observed in animal models and humans prompt researchers to explore further the antitumor potential of such biotherapy in an effort to reproduce in a larger set of patients the cascade of molecular events that characterizes the successful tumor immune rejection currently observed in a minority of vaccinated subjects. In this work, we summarize the principles and the main results of cancer vaccine strategies so far implemented for the treatment of patients with colorectal carcinoma. We also discuss the most recent preclinical tumor immunology insights that might change the way to design the next generation of cancer vaccines, hopefully improving the effectiveness of such a biotherapeutic approach.

Complete tumor prevention by engineered tumor cell vaccines employing nonviral vectors

We report that 100% mice survival after tumor challenge is achieved with cytokine-engineered cells employing nonviral lipoplexes and without using viral vectors. We describe this effect with cytokine-secreting tumor cell vaccines, based on cell clones or fresh transfected cells. Tumor cells were transfected with murine granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-4 plasmids employing the cationic lipid DOTAP, were irradiated (150 Gy) and kept frozen until use. The transfection efficacy was analyzed by qRT-PCR and flow cytometry. Vaccination induced potent antitumor rejection, resulting in 100% mice survival. Furthermore, the antitumor immunity was long lasting, since a two-fold survival delay was observed in mice after tumor rechallenge (6 months later). While cell clones secreting GM-CSF were the most effective in wild-type tumor cell rejection, little or no effect was observed with clones secreting IL-4. We found similar antitumor efficacy employing fresh transfected cells by nonviral procedures, demonstrating that cells genetically modified by nonviral vectors (both clones and fresh transfected cells) are a safe and efficient tool for antitumor vaccines. These vaccines allow us to achieve the highest antitumor efficacy based on nonviral gene therapy techniques. In addition, the vaccination success with fresh transfected cells simplifies the procedure and provides new insights into the clinical application of nonviral gene therapy procedures.

Exploiting dendritic cells for cancer immunotherapy: genetic modification of dendritic cells

Dendritic cells (DCs) are pivotal regulators of immune reactivity and immune tolerance. The observation that DCs can recruit naive T cells has invigorated cancer immunology and led to the proposal of DCs as the basis for vaccines designed for the treatment of cancer. Designing effective strategies to load DCs with antigens is a challenging field of research. The successful realization of gene transfer to DCs will be highly dependent on the employed vector system. Here, we review various viral and non-viral gene transfer systems, and discuss their distinct characteristics and possible advantages and disadvantages in respect to their use in DC-based immunotherapy.

Immunotherapy for melanoma metastatic to the orbit

PURPOSE

To present 3 cases of melanoma metastatic to the orbit treated with various traditional modalities including surgery and chemotherapy and being treated with melanoma vaccines and to present background information on immunotherapy.

METHODS

Retrospective review of 3 patients with melanoma metastatic to the orbit who were treated with melanoma vaccines along with conventional treatments. One patient had known orbital involvement before vaccine treatment; 2 patients had orbital metastases subsequent to vaccine administration.

RESULTS

Patients survived at least 13 months after the diagnosis of metastatic melanoma, with 1 patient surviving 51 months after the onset of metastases and administration of melanoma vaccine.

CONCLUSIONS

Although still unproven, immunotherapy with melanoma vaccines is a promising new treatment modality for metastatic melanoma with few side effects.

mRNA expression of tumor-associated antigens in melanoma tissues and cell lines

Tumor-associated antigens (TAA) are increasingly used as specific targets for immune therapy of malignant melanoma. The aim of the present study was to provide a basis for selecting the most suitable TAA by analyzing the mRNA expression of a large panel of TAA by RT-PCR and Northern blotting. We have chosen primers differentiating four groups of TAA (MAGE-A, MAGE-B, and two groups of GAGE-genes) and 13 individual TAA (MAGE-A2 and -A3, RAGE-1, -2, -3, and -4, LAGE-1a and -1b, NY-ESO-1, GAGE-1, SSX-2, SCP-1, and cTAGE-1) based on most recent sequence data. In addition, the RAGE-gene family has been separated into its four members by a novel designed nested PCR, which was confirmed by Northern analysis. Furthermore, the chromosomal organization and relationship between the RAGE-family and MOK was analyzed. RAGE-4 mRNA could be shown for the first time to be present in testis tissue. The most frequently expressed TAA were the MAGE-A and the GAGE-3,-4,-5,-6,-8 group, whereas among individual TAA MAGE-A2, -A3, RAGE-1, -3, and LAGE-1a/b were found within most specimens and are thus promising candidates for immune therapy. In comparison, melanoma metastatic specimens and cell lines show similar profiles of TAA expression, but individual TAA differ notably between both types of samples indicating that results from cell lines are not always applicable to tumor specimen.

Genetically engineered macrophages expressing IFN-gamma restore alveolar immune function in scid mice

Reversal of immunodeficiency in the lung by gene therapy is limited in part by the difficulty of transfecting lung cells in vivo. Many options exist for successfully transfecting cells in vitro, but they are not easily adapted to the in vivo condition. To overcome this limitation, we transduced macrophages in vitro with the murine IFN-gamma (mIFN-gamma) gene and intratracheally delivered the macrophages to express mIFN-gamma in vivo. A recombinant retroviral vector pSF91 system was modified to encode mIFN-gamma and enhanced green fluorescent protein (EGFP). A murine macrophage cell line J774A.1 transduced with the retroviral supernatant increased secretion from undetectable levels to 131.6 +/- 4.2 microg/ml mIFN-gamma at 24 h in vitro. The mIFN-gamma-producing macrophages were intratracheally instilled into mechanically ventilated scid mice. mIFN-gamma levels in the bronchoalveolar lavage increased from undetectable levels at baseline to 158.8 +/- 5.1 pg/ml at 48 h (P < 0.001). Analysis of the lavaged cells for EGFP expression revealed that EGFP expression was directly proportional to the number of transduced macrophages instilled into the lung. Immune function was partially restored in the alveolar spaces of scid mice with evidence of enhanced MHC class II antigen expression and increased phagocytosis (P < 0.05). Tumor necrosis factor alpha was increased from undetectable at baseline to 103.5 +/- 11.4 pg/ml. In contrast, i.p. administration of the engineered macrophages did not enhance IFN-gamma levels in the lung. Our study suggests airway delivery of genetically engineered macrophages expressing mIFN-gamma gene can partially restore significant immune activity in the lungs of immunodeficient mice.

Immune responses to the HLA-A*0201-restricted epitopes of tyrosinase and glycoprotein 100 enable control of melanoma outgrowth in HLA-A*0201-transgenic mice

Many of the Ags recognized by human melanoma-reactive CTL are derived from proteins that are also expressed in melanocytes. The possibility of self-tolerance to these epitopes has led to questions about their utility for antitumor immunotherapy. To investigate the issue, we established a preclinical model based on transgenic mice expressing a recombinant HLA-A*0201 molecule and B16 melanoma transfected to express this molecule. HLA-A*0201-restricted epitopes from the melanocyte differentiation proteins (MDP) tyrosinase and gp100 are expressed in both tumor cells and melanocytes, and the former is associated with self-tolerance. However, adoptive transfer of tyrosinase or gp100-reactive CTL developed from tolerant mice delayed tumor outgrowth, as did immunization with MDP peptide-pulsed dendritic cells. Protection was enhanced by the use of peptide ligands containing conservative substitutions that were cross-reactive with the original Ags. These data establish that CTL populations reactive against MDP-derived self-Ags can be activated to mount effective antitumor immunity and strongly support their continued development for tumor immunotherapy in humans.