Exploring dendritic cell based vaccines targeting survivin for the treatment of head and neck cancer patients

Novel Survivin Peptides Screened With Computer Algorithm Induce Cytotoxic T Lymphocytes With Higher Cytotoxic Efficiency to Cancer Cells

The identification of novel biomarkers and therapeutic targets in advanced cancer is critical for improving cancer diagnosis and therapeutics. Survivin (SV) is highly expressed predominantly in most cancer cells and tissues but is absent or undetectable in terminally differentiated normal adult tissues. Therefore, it functions as an almost universal tumor antigen. Peptides are short chains of amino acids linked by peptide bonds. To obtain novel SV decamers that are able to induce SV-specific cytotoxic T lymphocytes (CTLs) with a higher cytotoxic efficiency against cancer cells, major histocompatibility complex (MHC) peptide binding algorithms were conducted to predict nine modified SV₉₅ decamers (from SV_95–2 to SV_95–10) based on the natural SV_95–104 peptide sequence of ELTLGEFLKL (here defined as SV_95–1). The fluorescent density of each SV₉₅ peptide was determined by a MHC stability assay, followed by the generation of SV₉₅-specific CTLs with each SV₉₅ peptide (from SV_95–1 to SV_95–10) and human dendritic cells (DCs) loaded with Poly(lactic-co-glycolic) acid (PLGA) nanoparticles encapsulated with SV₉₅ peptide. Finally, IFN-γ ELISpot and CytoTox 96^® Non-Radioactive Cytotoxicity Assays were employed to verify their cytotoxic efficiency of the SV₉₅-specific CTLs generated with the corresponding artificial antigen presenting cells (aAPCs) containing SV₉₅ (SV_95–1 to SV_95–10) peptide. Furthermore, the cytotoxicity of the SV₉₅ specific CTLs generated with nine mutated SV₉₅ peptides was compared to the one generated with natural SV_95–1 peptide and TIL2080 cells. The results indicated that the HLA-A2-restricted mutated SV₉₅ epitope decamers (SV_95–6 and SV_95–7) showed significant higher binding ability compared to natural peptide SV_95–1 in MHC stability assay. More importantly, SV_95–specific CTLs with higher cytotoxicity were successfully induced with both SV_95–6 and SV_95–7 peptides, which significantly eliminated target cells (not only SV_95–1 peptide pulsed T2 cells, but also both HLA-A2 and SV positive cancer cells) when compared to those generated with natural SV_95–1 peptide and TIL2080 cells. These findings suggest that the SV_95–6 and SV_95–7 peptides are two novel HLA-A2-restricted CTL epitopes and may be useful for the immunotherapy for patients with survivin expressing cancer.

Study on the targeted therapy of oral squamous cell carcinoma with a plasmid expressing PE38KDEL toxin under control of the SERPINB3 promoter

Oral squamous cell carcinoma (OSCC) has a poor prognosis and a high risk of recurrence. To improve the efficacy of OSCC therapy, it is of great significance to explore gene therapy for OSCC. The use of specific genes to regulate the targeted expression of suicide genes is a hot topic in gene therapy for cancer. The SERPINB3 gene is highly active in squamous cell carcinoma, but nearly undetectable or present at a low level in normal tissues. This specificity suggests that the SERPINB3 promoter can be used for targeted OSCC therapy. Pseudomonas aeruginosa secretes PE38KDEL, an exotoxin derivative, as a suicide gene used in gene therapy. A SERPINB3 promoter-mediated PE38KDEL expression vector was created. The SERPINB3 gene expression was tested in different cell lines by RT-qPCR and Western blotting, and the SERPINB3 promoter activity was detected by luciferase assay. The SERPINB3 promoter was more active in the TCA8113 cell line than in the other cell lines. The target therapeutic potential of the toxin vector pSERPINB3-PE38KDEL was tested in the SERPINB3-positive TCA8113 cell line, the SERPINB3-negative MG63 cell line, and normal L02 cell line. The SERPINB3 gene was expressed at a high level in TCA8113 cells but a low level in MG63 and L02 cells. Transfection of the pSERPINB3-PE38KDEL plasmid effectively inhibited the proliferation and invasion of TCA8113 cells and induced cell apoptosis, but no significant damage to MG63 and L02 cells was observed. The results of in vitro experiments indicated that the pSERPINB3-PE38KDEL plasmid could be a promising strategy for targeted OSCC gene therapy.

Gene-modified dendritic cell vaccines for cancer

Dendritic cell (DC) vaccines are an immunotherapeutic approach to cancer treatment that use the antigen-presentation machinery of DCs to activate an endogenous anti-tumor response. In this treatment strategy, DCs are cultured ex vivo, exposed to tumor antigens and administered to the patient. The ex vivo culturing provides a unique and powerful opportunity to modify and enhance the DCs. As such, a variety of genetic engineering approaches have been employed to optimize DC vaccines, including the introduction of messenger RNA and small interfering RNA, viral gene transduction, and even fusion with whole tumor cells. In general, these modifications aim to improve targeting, enhance immunogenicity, and reduce susceptibility to the immunosuppressive tumor microenvironment. It has been demonstrated that several of these modifications can be employed in tandem, allowing for fine-tuning and optimization of the DC vaccine across multiple metrics. Thus, the application of genetic engineering techniques to the dendritic cell vaccine platform has the potential to greatly enhance its efficacy in the clinic.

Survivin, a molecular target for therapeutic interventions in squamous cell carcinoma

Squamous cell carcinoma (SCC) is the most common cancer worldwide. The treatment of locally advanced disease generally requires various combinations of radiotherapy, surgery, and systemic therapy. Despite aggressive multimodal treatment, most of the patients relapse. Identification of molecules that sustain cancer cell growth and survival has made molecular targeting a feasible therapeutic strategy. Survivin is a member of the Inhibitor of Apoptosis Protein (IAP) family, which is overexpressed in most of the malignancies including SCC and totally absent in most of the normal tissues. This feature makes survivin an ideal target for cancer therapy. It orchestrates several important mechanisms to support cancer cell survival including inhibition of apoptosis and regulation of cell division. Overexpression of survivin in tumors is also associated with poor prognosis, aggressive tumor behavior, resistance to therapy, and high tumor recurrence. Various strategies have been developed to target survivin expression in cancer cells, and their effects on apoptosis induction and tumor growth attenuation have been demonstrated. In this review, we discuss recent advances in therapeutic potential of survivin in cancer treatment.

Interaction of dendritic cells and T lymphocytes for the therapeutic effect of Dangguiliuhuang decoction to autoimmune diabetes

In traditional Chinese medicine (TCM), Dangguiliuhuang decoction (DGLHD) is an effective treatment of autoimmune diabetes. Here, we studied potential anti-diabetic mechanisms of DGLHD in a non-obese diabetic (NOD) mouse model. In vitro, DGLHD and individual active ingredients enhanced glucose uptake in HepG2 cells, inhibited T lymphocyte proliferation, and suppressed dendritic cells (DCs) function. In vivo, DGLHD significantly inhibited insulitis, delayed the onset and development of diabetes, promoted insulin secretion and sensitivity, and balanced partially normalized Th1 and Th2 cytokines in NOD mice. In addition, DGLHD increased α₁-antitrypsin (AAT-1), Bcl-2, and CyclinD1, and decreased Bax levels in pancreas, spleen, thymus, DCs, and a NIT-1 cell line, all consistent with protecting and repairing islet β cell. More detailed studies indicated that DGLHD regulated the maturation and function of DCs, decreased the percentage of merocytic dendritic cells (mcDCs) subset, and increased programmed death ligand-1 (PD-L1) expression in DCs. DGLHD also impeded T lymphocyte proliferation and promoted regulatory T cells (T_regs) differentiation in vivo. A JAK2-STAT3-dependent pathway was involved in the suppression by DGLHD of interactions between DCs and T lymphocyte. The experiments implicated five active ingredients in specific anti-diabetic actions of DGLHD. The results demonstrated the reasonable composition of the formula.

Oral delivery of Bacillus subtilis spore expressing enolase of Clonorchis sinensis in rat model: induce systemic and local mucosal immune responses and has no side effect on liver function

Caused by the consumption of raw or undercooked freshwater fish containing infective metacercariae of Clonorchis sinensis, human clonorchiasis remains a major public health problem in China. In previous study, we had expressed enolase from C. sinensis (CsENO) on the surface of Bacillus subtilis spore and the recombinant spore induced a pronounced protection in terms of reduced worm burden and eggs per gram feces, suggesting B. subtilis spore as an ideal vehicle for antigen delivery by oral treatment and CsENO as a promising vaccine candidate against clonorchiasis. In the current study, we detected CsENO-specific IgG and IgA levels both in serum and in intestinal mucus from rats orally administrated with B. subtilis spore surface expressing CsENO by ELISA. Lysozyme levels in serum and in intestinal mucus were analyzed too. In addition, IgA-secreting cells in intestine epithelium of the rats were detected by immunohistochemistry assay. The intestinal villi lengths of duodenum, jejunum, and ileum were also measured. Rats orally treated with B. subtilis spore or normal saline were used as controls. Our results showed that, compared with the control groups, oral administration of B. subtilis spore expressing CsENO induced both systemic and local mucosal immune response. The recombinant spores also enhanced non-specific immune response in rats. The spores had no side effect on liver function. Moreover, it might facilitate food utilization and digestion of the rats. Our work will pave the way to clarify the involved mechanisms of protective efficacy elicited by B. subtilis spore expressing CsENO and encourage us to carry out more assessment trails of the oral treated spore to develop vaccine against clonorchiasis.

Trial watch: Dendritic cell-based anticancer therapy

The use of patient-derived dendritic cells (DCs) as a means to elicit therapeutically relevant immune responses in cancer patients has been extensively investigated throughout the past decade. In this context, DCs are generally expanded, exposed to autologous tumor cell lysates or loaded with specific tumor-associated antigens (TAAs), and then reintroduced into patients, often in combination with one or more immunostimulatory agents. As an alternative, TAAs are targeted to DCs in vivo by means of monoclonal antibodies, carbohydrate moieties or viral vectors specific for DC receptors. All these approaches have been shown to (re)activate tumor-specific immune responses in mice, often mediating robust therapeutic effects. In 2010, the first DC-based preparation (sipuleucel-T, also known as Provenge®) has been approved by the US Food and Drug Administration (FDA) for use in humans. Reflecting the central position occupied by DCs in the regulation of immunological tolerance and adaptive immunity, the interest in harnessing them for the development of novel immunotherapeutic anticancer regimens remains high. Here, we summarize recent advances in the preclinical and clinical development of DC-based anticancer therapeutics.

Tumor antigen and MHC expression in glioma cells for immunotherapeutic interventions

AIM: To investigate the expression of tumor-antigens and major histocompatibility complex (MHC)-machinery components in glioblastoma multiforme cell lines flow cytometry staining methods were applied.

METHODS: Ten GBM cell lines (three commercially available: U-87 MG, U-138-MG and GMS-10 as well as seven newly established cell lines from individual patients in low-passages: HROG02, HROG04, HROG05, HROG06, HROG10, HROG13 and HROG17) were analyzed for expression of (I) general and (II) GBM-related tumor antigens as well as of (III) components of the MHC machinery by flow cytometry.

RESULTS: All cell lines expressed MHC class I with seven out of the ten being HLA-A02 positive. Four of the seven primary cell lines additionally expressed MHC class II in a constitutive manner. Of note, after interferon gamma (IFN-γ) treatment, all seven cell lines expressed MHC class II. The tumor associated antigens (TAA) EGFR and survivin were expressed at high levels in all cell lines; whereas MART-1, RHAMM, WT-1 and IL-13Rα were expressed by at least half of the cell lines and HER2/neu, MAGE-1 and tyrosinase were expressed only by few cell lines. However, all cell lines expressed at least two of the candidate antigens included into this analysis.

CONCLUSION: No obvious differences between commercially available and newly-established cell lines were observed. Thus, the latter in low-passages are interesting for (therapy-) screening and immunotherapeutic strategies.

Dendritic cell vaccines targeting survivin in head and neck cancer

Evaluation of: Turksma AW, Bontkes HJ, Ruizendaal JJ et al. Exploring dendritic cell based vaccines targeting survivin for the treatment of head and neck cancer patients. J. Transl. Med. 11, 152-165 (2013). Survivin has been identified to be an inhibitor of apoptosis and is highly expressed in many cancers. A number of strategies have targeted survivin as a novel cancer therapy approach. The evaluated paper makes a number of observations regarding the presence of survivin-specific T cells, as well as attempts for in vitro expansion. The research team has shown that survivin-specific T cells can be measured ex vivo in the peripheral blood of patients with head and neck squamous cell carcinoma by tetramer analysis and from the tumor-draining lymph node of a patient with locally advanced breast cancer by ELIspot analysis. Furthermore, dendritic cells electroporated with survivin and cytokine (i.e., IL-12 and IL-21) mRNA can be used to generate survivin-specific T cells in vitro. However, the enriched or cloned survivin-specific T cells isolated from patients or obtained by in vitro induction could not be maintained for prolonged periods of time. The study team proposed that one explanation for this is fracticide, as activated T cells were shown to express survivin. The evaluated paper therefore concluded that strategies that rely on expansion and adoptive transfer of survivin-specific T cells would not be possible.