Vaccination strategies in patients with renal cell carcinoma

Tumor-Associated Antigens (TAAs) for the Serological Diagnosis of Osteosarcoma

Osteosarcoma (OS) is the most common form of malignant bone tumor found in childhood and adolescence. Although its incidence rate is low among cancers, the prognosis of OS is usually poor. Although some biomarkers, such as p53, have been identified in OS, the association between the biomarkers and clinical outcome is not well understood. Thus, it is necessary to establish a method to identify patients diagnosed with OS at an early stage. It is becoming obvious that anti-tumor-associated antigens (TAAs) autoantibodies (TAAbs) in sera could be used as serological biomarkers in the detection of many different types of cancers. This notion indicates that TAAbs are considered as immunological “sentinels” associated with tumorigenesis underlying molecular events. It provides new insights into the molecular and cellular biology of the differential diagnosis of cancers. What’s more, it is reported that a customized TAA array could significantly increase the sensitivity/specificity. TAA arrays also have great application prospects in detecting cancer at an early stage, monitoring cancer progression, discovering new therapeutic targets, and designing personalized treatment. In this review, we provide an overview of the TAAs identified in OS as well as the possibility that TAAs and TAAbs system be used as biomarkers in the immunodiagnosis and prognosis of OS.

Small interfering RNAs (siRNAs) in cancer therapy: a nano-based approach

Cancer is one of the most complex diseases that has resulted in multiple genetic disorders and cellular abnormalities. Globally, cancer is the most common health concern disease that is affecting human beings. Great efforts have been made over the past decades in biology with the aim of searching novel and more efficient tools in therapy. Thus, small interfering RNAs (siRNAs) have been considered one of the most noteworthy developments which are able to regulate gene expression following a process known as RNA interference (RNAi). RNAi is a post-transcriptional mechanism that involves the inhibition of gene expression through promoting cleavage on a specific area of a target messenger RNA (mRNA). This technology has shown promising therapeutic results for a good number of diseases, especially in cancer. However, siRNA therapeutics have to face important drawbacks in therapy including stability and successful siRNA delivery in vivo. In this regard, the development of effective siRNA delivery systems has helped addressing these issues by opening novel therapeutic windows which have allowed to build up important advances in Nanomedicine. In this review, we discuss the progress of siRNA therapy as well as its medical application via nanoparticle-mediated delivery for cancer treatment.

Immune consequences of tyrosine kinase inhibitors that synergize with cancer immunotherapy

Combination therapy for the treatment of cancer is becoming increasingly essential as we gain improved understanding of the complexity of cancer progression and the mechanisms by which cancer cells become resistant to single-agent therapy. Recent studies, both clinical and preclinical, have suggested that immunotherapy is a promising approach to the treatment of cancer; however, strategies to improve its clinical efficacy are still needed. A number of recent studies have indicated that antiangiogenic tyrosine kinase inhibitors (TKIs) target multiple components of the tumor microenvironment and are an ideal class of agents for synergizing with cancer immunotherapy. TKIs are well known to modulate tumor endothelial cells, leading to vascular normalization; however, these agents have also been recently shown to decrease tumor compactness and tight junctions, thereby reducing solid tumor pressure and allowing for improved perfusion of collapsed vessels and increased tumor oxygenation. In addition, some TKIs are capable of inducing immunogenic modulation, whereby tumor cells are sensitized to killing by T lymphocytes. Moreover, a number of TKIs have been shown to be involved in immune subset conditioning, increasing the frequency and function of effector immune elements, while decreasing the number and function of immune suppressor cells. The alteration of the immune landscape, direct modification of tumor cells, and improved vascular perfusion leads to improved antitumor efficacy when antiangiogenic TKIs are combined with immunotherapy. Collectively, the data presented in this review support the clinical combination of multi-targeted antiangiogenic TKIs, including but not limited to cabozantinib, sunitinib, and sorafenib, as well as to other antiangiogenic therapies, such as the anti-VEGF antibody bevacizumab, with cancer vaccines for improved treatment of solid tumors.

Characterization of small spheres derived from various solid tumor cell lines: are they suitable targets for T cells?

T cell based immunotherapy has been investigated in a variety of malignancies and analyses have been mostly founded on in vitro data with tumor cell monolayers. However, three-dimensional (3D) culture models might mimic more closely the 'in vivo' conditions than 2D monolayers. Therefore, we analyzed the expression of tumor-associated antigens (TAA) and of molecules involved in antigen processing and presentation (APM) in tumor spheres, which served as an in vitro model for micrometastasis which might be enriched in tumor propagating cancer stem cells. For enrichment of sphere cells 12 human solid tumor cell lines were cultured in serum-free medium. Expression of a variety of TAA and APM were analyzed by RT-PCR and/or flow cytometry and compared to expression in corresponding adherent bulk cells grown in regular growth medium. Compared to adherent cells, spheres showed equal or higher mRNA expression levels of LMP2, LMP7 and MECL-1, of TAP1 and TAP2 transporters and, surprisingly, also of TAA including differentiation antigens. However, downregulation or loss of HLA-I and HLA-II molecules in spheres was observed in 8 of 10 and 1 of 2 cell lines, respectively, and was unresponsive to stimulation with IFN-γ. Although tumor spheres express TAA and molecules of intracellular antigen processing, they are defective in antigen presentation due to downregulation of HLA surface expression which may lead to immune evasion.

Isolation and identification of renal cell carcinoma-derived peptides associated with GP96

We determined the possible associated determinants and analyzed whether gp96-_associated antigenic peptides can be found in renal cell carcinoma (RCC). The gp96-peptide complexes were chromatographically purified from resected tumor tissue of RCC patients. SDS-PAGE and Western blot analysis confirmed gp96 using the gp96 monoclonal antibody, and its concentration was measured using BCA. Approximately 20 to 50 μg gp96-peptide complexes was obtained from 1 g RCC tissue. The mass spectrometry (MS) analysis of the eluted peptides included the initial profiling using matrix-assisted laser desorption/ionization time-of-flight MS. Quadrupole time-of-flight MS combined with the Mascot search engine was used to identify the peptides and find proteins from primary sequence databases. MS analysis results demonstrated that the mass range of peptide associated with gp96 was from 1046.48 to 3501.56 Da. Further research confirmed the sequences of two gp96-associated peptides, namely, LVPLEGWGGNVM and PPVYYVPYVVL. However, the original protein of the two peptides could not be found. The results demonstrated that the gp96-associated peptides are small molecular peptides, and the two peptides are deduced to be RCC-associated peptides. The identified peptides were confirmed to be associated with gp96 using the protocols described above. However, the specificity and relevance of the association to the immunogenicity of gp96 remains to be examined. Further analysis must be accomplished before the findings can be applied in peptide vaccine.

Quality of life during dendritic cell vaccination against metastatic renal cell carcinoma

Patients with metastatic renal cell carcinoma (RCC) undergoing cytokine or targeted therapies may show a remarkable decline in quality of life (QoL). We wanted to evaluate QoL in patients with metastatic RCC undergoing therapeutic vaccination with dendritic cells (DCs). In a cross-sectional analysis, QoL was therefore assessed in RCC patients participating in three consecutive clinical trials of DC vaccination. Before the first and after the third vaccination with DCs, patients completed a QoL questionnaire (EORTC QLQ-C30, version 3). Data were transformed into scale scores and analysed using SPSS 12.0 software. Mean values of the resulting scores obtained before and after DC vaccination were compared using students t test and Wilcoxon rank-sum test. P < 0.05 was considered statistically significant. The questionnaire was completed by 55 of 71 patients (compliance rate, 77.5%) who had a median age of 58.7 years (from 30 to 75 years). No significant reductions in functioning scales including physical, emotional and social criteria as well as symptom scores, which assess typical symptoms of tumour therapies, were observed indicating that QoL remained high during DC vaccination. Significant correlations were found between overall survival and functional as well as symptom scores. Our data indicate that DC vaccination, which is a personalised treatment modality, maintains QoL and thus represents an attractive nontoxic treatment option for patients with metastatic RCC. It will be important to identify the most effective conditions of DC vaccination including combinations with other therapeutics to maximise clinical efficacy while still preserving QoL.

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.

The tipping point for combination therapy: cancer vaccines with radiation, chemotherapy, or targeted small molecule inhibitors

Therapeutic cancer vaccines are a unique treatment modality in that they initiate a dynamic process of activating the host immune system, which can then be exploited by concurrent or subsequent therapies. The addition of immunotherapy to standard-of-care cancer therapies has shown evidence of efficacy in preclinical models and in the clinical setting. This review examines the preclinical and clinical interactions between vaccine-mediated tumor-specific immune responses and local radiation, systemic chemotherapy, or select small molecule inhibitors, as well as the potential synergy between these modalities.

Antitumor efficacy of viable tumor vaccine modified by heterogenetic ESAT-6 antigen and cytokine IL-21 in melanomatous mouse

The goal of this study was to investigate whether glycosylphosphatidylinositol (GPI)-anchored 6 kDa early secreted antigenic target (ESAT-6) and IL-21-producing B16F10/ESAT-6-GPI-IL-21 viable vaccine would induce antitumor efficacy. Mice were immunized with B16F10/ESAT-6-GPI-IL-21 vaccine and challenged by B16F10 cells 2 weeks later. Antitumor efficacy and mechanisms of the vaccine were analyzed. Vaccination with the viable B16F10/ESAT-6-GPI-IL-21 vaccine resulted in an increase of IFN-γ level and the CD8(+)CTL cytotoxicity, a decrease in TGF-β generation and increase in the expression of miR-200c that serves as melanoma suppressor by directly targeting zinc-finger E-box binding homeobox 1 to inhibit epithelial-mesenchymal transition and block tumor metastasis. The vaccine significantly inhibited the melanoma growth, reduced the lung melanoma nodules, and prolonged the mouse survival compared with the controls. These findings highlighted IL-21 as an immune adjuvant in an engineered viable tumor vaccine to reinforce heterogenetic antigen ESAT-6 immune tolerance break to induce powerful antitumor efficacy in mice.

Consequence of dose scheduling of sunitinib on host immune response elements and vaccine combination therapy

Our study investigated the immunomodulatory effects of sunitinib to rationally design combinational platforms with immunotherapies for the treatment of solid tumors. Using a mouse model, we studied the effects of sunitinib given for 4 weeks at concentrations comparable to 37.5-50 mg/day in humans, followed by 2 weeks off the drug (sunitinib 4/2). We assessed the effect of differently timed combinations of sunitinib and a poxvirus-based vaccine encoding carcinoembryonic antigen (CEA) plus 3 costimulatory molecules on immune responses in CEA-transgenic (CEA-Tg) mice. Antitumor studies were performed in CEA-Tg mice bearing CEA-transfected MC38 murine colon carcinomas (MC38-CEA), treated either concurrently or sequentially with sunitinib and vaccine. In vitro, sunitinib inhibited PDGFR phosphorylation on MC38-CEA cells at concentrations similar to those biologically available during human treatment. In vivo, one cycle of sunitinib 4/2 caused bimodal immune effects: (a) decreased regulatory cells during the 4 weeks of treatment and (b) an immune-suppression rebound during the 2 weeks of treatment interruption. In a model using CEA-Tg mice bearing CEA(+) tumors, continuous sunitinib followed by vaccine increased intratumoral infiltration of antigen-specific T lymphocytes, decreased immunosuppressant T regulatory cells and myeloid-derived suppressor cells, reduced tumor volumes and increased survival. The immunomodulatory activity of continuous sunitinib administration can create a more immune-permissive environment. In combination with immunotherapies, sunitinib treatment should precede vaccine, to precondition the immune system, to maximize the response to vaccine-mediated immune enhancement.

Immunotherapy for renal cell carcinoma

Although several cytokines have shown antitumor activity in renal cell carcinoma (RCC), the most consistent results have been reported with interleukin-2 (IL-2) and interferon (IFN). Recent insights into how the immune response to a tumor is regulated hold the promise of allowing patients to obtain a durable response to immunotherapy, perhaps without the significant toxicity associated with conventional approaches. This review describes how improvements in patient selection, combination therapy, and investigational agents might expand and better define the role of immunotherapy in metastatic RCC.

Dendritic cell based tumor vaccination in prostate and renal cell cancer: a systematic review and meta-analysis

BACKGROUND

More than 200 clinical trials have been performed using dendritic cells (DC) as cellular adjuvants in cancer. Yet the key question whether there is a link between immune and clinical response remains unanswered. Prostate and renal cell cancer (RCC) have been extensively studied for DC-based immunotherapeutic interventions and were therefore chosen to address the above question by means of a systematic review and meta-analysis.

METHODOLOGY/PRINCIPAL FINDINGS

Data was obtained after a systematic literature search from clinical trials that enrolled at least 6 patients. Individual patient data meta-analysis was performed by means of conditional logistic regression grouped by study. Twenty nine trials involving a total of 906 patients were identified in prostate cancer (17) and RCC (12). Objective response rates were 7.7% in prostate cancer and 12.7% in RCC. The combined percentages of objective responses and stable diseases (SD) amounted to a clinical benefit rate (CBR) of 54% in prostate cancer and 48% in RCC. Meta-analysis of individual patient data (n = 403) revealed the cellular immune response to have a significant influence on CBR, both in prostate cancer (OR 10.6, 95% CI 2.5-44.1) and in RCC (OR 8.4, 95% CI 1.3-53.0). Furthermore, DC dose was found to have a significant influence on CBR in both entities. Finally, for the larger cohort of prostate cancer patients, an influence of DC maturity and DC subtype (density enriched versus monocyte derived DC) as well as access to draining lymph nodes on clinical outcome could be demonstrated.

CONCLUSIONS/SIGNIFICANCE

As a 'proof of principle' a statistically significant effect of DC-mediated cellular immune response and of DC dose on CBR could be demonstrated. Further findings concerning vaccine composition, quality control, and the effect of DC maturation status are relevant for the immunological development of DC-based vaccines.

Update on vaccine development for renal cell cancer

Renal cell carcinoma (RCC) remains a significant health concern that frequently presents as metastatic disease at the time of initial diagnosis. Current first-line therapeutics for the advanced-stage RCC include antiangiogenic drugs that have yielded high rates of objective clinical response; however, these tend to be transient in nature, with many patients becoming refractory to chronic treatment with these agents. Adjuvant immunotherapies remain viable candidates to sustain disease-free and overall patient survival. In particular, vaccines designed to optimize the activation, maintenance, and recruitment of specific immunity within or into the tumor site continue to evolve. Based on the integration of increasingly refined immunomonitoring systems in both translational models and clinical trials, allowing for the improved understanding of treatment mechanism(s) of action, further refined (combinational) vaccine protocols are currently being developed and evaluated. This review provides a brief history of RCC vaccine development, discusses the successes and limitations in such approaches, and provides a rationale for developing combinational vaccine approaches that may provide improved clinical benefits to patients with RCC.

Advances in cellular therapy for the treatment of thyroid cancer

Up to now, there are no curative therapies available for the subset of metastasized undifferentiated/anaplastic thyroid carcinomas. This review describes the possible use of immunocompetent cells which may help to restore the antitumor immune recognition for treating an existing tumor or preventing its recurrence. The most prominent experimental strategy is the use of dendritic cells (DCs) which are highly potent in presenting tumor antigens. Activated DCs subsequently migrate to draining lymph nodes where they present antigens to naïve lymphocytes and induce cytotoxic T cells (CTL). Alternatively to DC therapy, adoptive cell transfer may be performed by either using natural killer cells or ex vivo maturated CTLs. Within this review article we will focus on recent advances in the understanding of anti-tumor immune responses, for example, in thyroid carcinomas including the advances which have been made for the identification of potential tumor antigens in thyroid malignancies.

Ten-year survival analysis for renal carcinoma patients treated with an autologous tumour lysate vaccine in an adjuvant setting

About 30% of renal cell carcinomas (RCC) will develop recurrence after surgery. Despite evidence for a significantly improved survival by autologous tumour cell vaccination therapy, the procedure has not become standard. Between August 1993 and December 1996, 1,267 RCC patients undergoing radical nephrectomy in 84 German hospitals were subsequently treated by autologous tumour cell vaccination therapy. The study group comprised 692 patients with complete follow-up (stages pT2-3, pNx-2, M0 based on the TNM classification, 4th edition). Subsequent propensity-score matching according to 7 defined criteria with 861 control patients undergoing nephrectomy alone without adjuvant treatment at the Carl-Thiem-Hospital Cottbus, resulted in 495 matched pairs. Overall and stage-specific survival rates were analysed after a median follow-up of 131 months. The 5- and 10-year overall survival (OS) rates were 80.6 and 68.9% in the vaccine group and 79.2 and 62.1% in the control group (p = 0.066). Patients with pT3 stage RCC revealed 5- and 10-year OS rates of 71.3 and 53.6% in the study group and 65.4 and 36.2% in the control group (p = 0.022). In multivariable analysis, patients in the vaccine group showed a significantly improved survival both in the whole study group (HR = 1.28, p = 0.030) and in the subgroup presenting with pT3 stage tumours (HR = 1.67, p = 0.011). Adjuvant treatment with autologous vaccination therapy resulted in a significantly improved overall survival in pT3 stage RCC patients, suggesting benefit especially in this subgroup. However, controlled clinical trials integrating the recent TNM classification and further risk constellations are required to define additional patient groups that may derive benefit from this treatment.