Combination nonviral cytokine gene therapy for head and neck cancer

Gene delivery to carcinoma cells via novel non-viral vectors: nanoparticle tracking analysis and suicide gene therapy

Suicide gene therapy of oral squamous cell carcinoma (OSCC) may be a viable approach to the treatment of this cancer. However, human OSCC cells are relatively resistant to efficient transfection by non-viral vectors. To identify an optimal vector for gene delivery, we compared the transfection activities and efficiencies of Glycofect, Metafectene, Metafectene Pro, Metafectene Easy and FuGENE HD, using the OSCC cell line, HSC-3, and the cervical carcinoma cell line, HeLa. The size distribution and ζ-potential of the complexes of these vectors with plasmid DNA were assessed by nanoparticle tracking analysis and electrophoretic mobility measurements, respectively. Metafectene Easy and FuGENE HD mediated the highest transfection activity (measured as luciferase expression) and efficiency (measured as the percentage of cells transfected with ß-galactosidase). These vectors were used to deliver a plasmid encoding herpes simplex virus thymidine kinase, followed by ganciclovir treatment. By day 9, HeLa cell viability was 22±3% of controls with FuGENE HD and 26±3% with Metafectene Easy. The viability of HSC-3 cells was 42±25% with FuGENE HD, and 58±28% with Metafectene Easy. The reduction in viability was statistically significant in both cases (p⩽0.005; average of 3 independent experiments), although there was considerable variability between experiments with the HSC-3 cells.

Co-transfection of dendritic cells with AFP and IL-2 genes enhances the induction of tumor antigen-specific antitumor immunity

Dendritic cells (DCs) are highly efficient, specialized antigen-presenting cells and DCs transfected with tumor-related antigens are regarded as promising vaccines in cancer immunotherapy. The aim of the present study was to investigate whether DCs co-transfected with the α-fetoprotein (AFP) and human interleukin-2 (IL-2) genes were able to induce stronger therapeutic antitumor immunity in transfected DCs. In this study, DCs from hepatocellular carcinoma (HCC) patients were co-transfected with the IL-2 gene and/or the AFP gene. The reverse transcription-PCR (RT-PCR) data revealed that the DCs transfected with the adenovirus AdAFP/IL-2 expressed AFP and IL-2. The DCs co-transfected with IL-2 and AFP (AFP/IL-2-DCs) enhanced the cytotoxicities of cytotoxic T lymphocytes (CTLs) and increased the production of IL-2 and interferon-γ significantly compared with their AFP-DC, green fluorescent protein (GFP)-DC, DC or phosphate-buffered saline (PBS) counterparts. In vivo data suggested that immunization with AFP-DCs enhances antigen-specific antitumor efficacy more potently than immunization with IL-2-DCs or AFP-DCs. These findings provide a potential strategy to improve the efficacy of DC-based tumor vaccines.

Review: novel nonviral delivery approaches for interleukin-12 protein and gene systems: curbing toxicity and enhancing adjuvant activity

It has become increasingly apparent that the ability to generate an optimal host immune response requires effective cross talk between the innate and adaptive components of the immune system. Pro-inflammatory cytokines, in particular those that can induce a danger signal, often called signal 3, are crucial in this role of initiating and augmenting the presentation of exogenous antigen to T cells by dendritic cells. Interleukin-12 (IL-12) in particular has been defined as a "signal 3" cytokine required for the antigen cross priming. Given this unique interactive function, a significant amount of work has been performed to define possible therapeutic applications for IL-12. Systemic IL-12 administration can clearly act as a potent adjuvant for postvaccination T cell responses in a variety of diseases. As an example, in the cancer setting, systemic IL-12 is capable of suppressing tumor growth, metastasis, and angiogenesis in vivo. IL-12, however, has been associated with significant dose- and schedule-dependent toxicity in early clinical trials, results that have proven to be a major obstacle to its clinical application. Recent research has focused on decreasing the toxicity of IL-12 using different delivery approaches, including virus-based and gene-modified cell-based delivery. Although effective, these approaches also have limitations, including the generation of neutralizing antibodies, in addition to lacking the simplicity and versatility required for universal clinical application. Thus, there is a significant interest in the development of alternative delivery approaches for IL-12 administration that can overcome these issues. Several nonviral delivery approaches for IL-12 protein or gene expression vectors are being defined, including alum, liposomes, and polymer-based delivery. These developing approaches have shown promising adjuvant effects with significantly lessened systemic toxicity. This article discusses the potential capabilities of these nonvirus-based IL-12 delivery systems in different disease settings, including allergy, infection, and cancer.

Immunological aspects of head and neck cancer: biology, pathophysiology and therapeutic mechanisms

Advanced cancer and head and neck cancer, in particular, remains a major clinical challenge with its associated morbidity and inevitable mortality. Local control of early disease is achievable in many solid tumours with current surgical and radiotherapeutic techniques but metastatic disease is associated with poor outcome and prognosis. It is known that, by the time of presentation, many patients will already have occult microscopic metastatic disease, and surgery and radiotherapy will not result in long-term survival. What little effect modern chemotherapeutic agents have on microscopic disease is, however, limited by systemic toxicity and multi-drug resistance. Immune surveillance is postulated to be operative in man. There is evidence, however, that patients with progressive tumour growth have failure of host defences both locally and systemically. Various possible defects and tumour escape mechanisms are discussed in the review. Immunotherapy and, in particular adoptive T cell therapy and DC therapy, show promise as putative tumour-specific therapy with clinical benefits. These techniques are undergoing development and evaluation in phase 1 clinical trials. Preliminary data suggest that the treatments are well tolerated. Unfortunately, there is limited evidence of significant and prolonged improvements in clinical outcome. Further developments of beneficial protocols (adjuvants, mode and frequency of vaccination etc) and multicentre studies of the use of immunotherapy in cancer are now required.

Plasmid vaccines and therapeutics: from design to applications

In the late 1980s, Vical and collaborators discovered that the injection into tissues of unformulated plasmid encoding various proteins resulted in the uptake of the plasmid by cells and expression of the encoded proteins. After this discovery, a period of technological improvements in plasmid delivery and expression and in pharmaceutical and manufacturing development was quickly followed by a plethora of human clinical trials testing the ability of injected plasmid to provide therapeutic benefits. In this chapter, we summarize in detail the technologies used in the most recent company-sponsored clinical trials and discuss the potential for future improvements in plasmid design, manufacturing, delivery, formulation and administration. A generic path for the clinical development of plasmid-based products is outlined and then exemplified using a case study on the development of a plasmid vaccine from concept to clinical trial.

IL-12 pretreatments enhance IFN-alpha-induced Janus kinase-STAT signaling and potentiate the antitumor effects of IFN-alpha in a murine model of malignant melanoma

IFN-alpha 2b (IFN-alpha) has been used to treat patients with metastatic malignant melanoma and patients rendered disease-free via surgery but at high risk for recurrence. We hypothesized that IL-12 pretreatments would result in endogenous IFN-gamma production, and that this, in turn, would up-regulate levels of Janus kinase-STAT signaling intermediates and lead to increased expression of genes regulated by IFN-alpha. Treatment of PBMCs with IL-12 stimulated a significant and dose-dependent production of IFN-gamma. Pretreatment of PBMCs and tumor cells with IFN-gamma-containing supernatants from IL-12-stimulated PBMCs led to up-regulation of STAT1, STAT2, and IFN regulatory factor 9 (IRF9) and potentiated IFN-alpha-induced STAT signaling within PBMCs and tumor cells. These effects were abrogated by neutralization of IFN-gamma in the PBMC supernatants with an anti-IFN-gamma Ab. Pretreatment of HT144 melanoma cells and PBMCs with IFN-gamma or IFN-gamma-containing supernatants enhanced the actions of IFN-alpha at the transcriptional level, as measured by real-time RT PCR analysis of the IFN-stimulated gene 15. Experiments in wild-type C57BL/6 and IFN-gamma receptor knockout (B6.129S7-Ifngr(tm1Agt)) mice demonstrated that a regimen of IL-12 pretreatment, followed by IFN-alpha, could cure mice of i.p. B16F1 melanoma tumors (p < 0.007), whereas mice treated with either agent alone or PBS succumbed to fatal tumor burden. However, this treatment regimen did not significantly prolong the survival of IFN-gamma-deficient (B6.129S7-Ifng(tm1Ts)) mice compared with mice treated with IFN-alpha alone. These results suggest that the response to IFN-alpha immunotherapy can be significantly enhanced by IL-12 pretreatment, and this effect is dependent upon endogenous IFN-gamma production and its actions on melanoma cells.

Gene therapy of anaplastic thyroid carcinoma with a single-chain interleukin-12 fusion protein

Anaplastic thyroid carcinoma is the most aggressive type of thyroid malignancy with a mean survival time of less than 8 months. No effective therapeutic approach is currently available, making the development of novel treatments necessary. Interleukin (IL)-12 is a proinflammatory heterodimeric cytokine with strong antitumor activity. In the present study, we investigated the potential of IL-12 gene therapy for anaplastic thyroid carcinoma in BALB/c (nu/nu) nude mice. A single-chain IL-12 fusion protein construct was created to assure equal expression of its p35 and p40 subunits. Human anaplastic thyroid carcinoma cell line ARO was stably transfected with an IL-12 expression plasmid under the control of cytomegalovirus (CMV) promoter (scIL-12/CMVpDNA). High levels of functional IL-12 (26.78 +/- 4.11 ng/ml per 10(6) cells per 48 hr) were produced by scIL-12-transfected ARO cells (ARO/IL-12). Tumorigenicity in nude mice was completely lost in scIL-12-transfected ARO cells, as demonstrated by the lack of tumor formation after subcutaneous injection of 2 x 10(6) ARO/IL-12 cells, even though there was no difference in cell proliferation between ARO and ARO/IL-12 cells. Tumor growth was observed after challenge with ARO tumor cells, indicating that protective immunity had not developed against the parental cells. Furthermore, the growth rate of established subcutaneous ARO tumors was significantly reduced by either subcutaneous injection of 2 x 10(6) ARO/IL-12 cells weekly or intramuscular injection of 50 microg scIL-12/CMVpDNA twice weekly. The antineoplastic activity of ARO/IL-12 cells was, however, abrogated by intraperitoneal injection of anti-natural killer (NK) cell antibody. Moreover, significantly higher number of ARO/IL-12 cells and ARO cells were killed by splenocytes from nude mice previously treated with ARO/IL-12 compared to those treated with ARO cells (32% vs. 9% when ARO were used as target cells, 43% vs. 17% when ARO/IL12 were used as target cells; p < 0.01) in an in vitro cytotoxicity assay. Again, tumor cell killing was neutralized by the addition of anti-NK cell antibody in the assay. In conclusion, we have demonstrated successful gene therapy with a scIL-12 fusion protein against anaplastic thyroid carcinoma in an in vivo model. The immune response against ARO/IL-12 cells is mediated by NK cells. These results may set the stage for clinical application of IL-12 gene therapy for poorly differentiated thyroid carcinoma.

Progress in Head and Neck Cancer Immunotherapy: Can Tolerance and Immune Suppression Be Reversed?

The incidence of squamous cell carcinoma of the head and neck (SCCHN) is greater than 40,000 cases per year in the United States, and approximately 500,000 cases annually worldwide. Despite significant advances in detection, ablation, and reconstruction, survival has not improved appreciably over the past few decades. Therefore, novel approaches are necessary to provide head and neck oncologists with a more effective armamentarium against this challenging disease. Cancer immunotherapy describes various approaches to expand and activate the immune system to control tumor growth in vivo. So far, immunotherapy appears to have had applicability in conjunction with other therapeutic interventions that treat residual tumor cells after therapy or to reduce the occurrence of second primary tumors. In particular, diseases such as SCCHN are attractive candidates for novel therapeutic approaches, since the standard treatments have not yet successfully controlled this disease with sufficiently high success rates. This article reviews adjuvant immunotherapeutic strategies currently in trials or under development for SCCHN patients, including vaccination or cytokine immunostimulation.

Enhanced adjuvanticity of interleukin-2 plasmid DNA administered in polyethylenimine complexes

We report here the enhanced adjuvant effect of murine interleukin-2 plasmid DNA (mIL-2) by complexation with a cationic polymer polyethylenimine (PEI). The mRNA expression of mIL-2 was observed at C2C12 cells after treatment with pVAXmIL-2 in PEI-complexed form, but not in naked plasmid DNA. In vivo, the plasmid DNA levels of mIL-2 at the administered muscle tissues were prolonged up to 14 days after intramuscular administration in PEI complexes. Moreover, the mRNA expression level in the muscle was 54-fold higher in PEI-complexed pVAXmIL-2 than in naked pVAXmIL-2 at 14 days after intramuscular administration. Mice were immunized on Days 0 and 28 by intramuscular administration of hepatitis B surface antigen (HBsAg) alone or with pVAXmIL-2 in naked or PEI complexes. At 8 weeks after the first immunization, mice coadministered with HBsAg plus pVAXmIL-2 in PEI complexes showed the serum IgG titer 72- and 208-fold higher as compared to those treated with HBsAg plus naked pVAXmIL-2 and with HBsAg alone, respectively. Though both HBsAg-specific IgG(1) and IgG(2a) immune responses were increased upon complexation of pVAXmIL-2 with PEI, IgG(2a) was more effectively induced relative to IgG(1). These results suggest that the complexation with PEI could be useful for prolonging in vivo expression of genetic cytokine adjuvants and enhancing their adjuvanticity for subunit vaccines.

Polyethylenimine-mediated cellular uptake, nucleus trafficking and expression of cytokine plasmid DNA

Although polyethylenimine (PEI) has been widely used as a nonviral vector, there is little mechanistic understanding on PEI-mediated delivery. Here, we studied whether the expression of murine interleukin-2 (mIL-2) plasmids could be improved by complexation with PEI at various N/P ratios, and whether the cellular uptake, nuclear translocation, and retention of plasmids could be affected by the N/P ratios. Compared with the naked mIL-2, PEI/mIL-2 complexes showed at least two orders of magnitude higher expression at Raw264 cells in the N/P ratio-dependent manner. PEI-mediated cellular uptake and nuclear trafficking of plasmids, quantitated by competitive polymerase chain reaction, also depended on the N/P ratios showing the highest cell and nuclear levels of plasmids at 10/1. The higher cellular levels of plasmid DNA after PEI-mediated delivery were also observed in other cell lines. Unlike naked plasmids, PEI/mIL-2 complexes (N/P ratios >/=4/1) showed prolonged cellular and nuclear retention of mIL-2 plasmids. The nuclear translocation and higher cellular level of plasmids given in PEI complexes were similarly observed by fluorescence microscopy. Moreover, PEI/mIL-2 complexes revealed high stability against DNase I, partly explaining the prolonged subcellular retention. These results indicate that the expression of plasmid mIL-2 might be highly enhanced by complexation with PEI and that such increased expression could be attributed by the higher cellular uptake, nuclear translocation and prolonged retention.