Role In Cancer Immunotherapy Research Articles

A carboxymethyl dextran-based polymeric conjugate as the antigen carrier for cancer immunotherapy

BackgroundAntigen-specific cytotoxic T lymphocytes (CTLs), which eliminate target cells bearing antigenic peptides presented by surface major histocompatibility complex (MHC) class I molecules, play a key role in cancer immunotherapy. However, the majority of tumors are not immunologically rejected since they express self-antigens which are not recognized by CTLs as foreign. To foreignize these tumors for CTL-mediated immunological rejection, it is essential to develop carriers that can effectively deliver foreign antigens to cancer cells.MethodsA polymeric conjugate, composed of a carboxymethyl dextran (CMD) as the backbone and ovalbumin (OVA) as a model foreign antigen, was prepared to investigate its potential as the antigen carrier for cancer immunotherapy.ResultsAn in vitro cellular uptake study showed that the conjugate was successfully taken up by TC-1 cervical cancer cells. When CMD-OVA was systemically administered to tumor-bearing mice, the strong fluorescence signal was observed at the tumor site over the whole period of time period, suggesting high tumor targetability of the conjugate. Compared to free OVA, CMD-OVA induced significantly higher antigen presentation at the tumor site.ConclusionsThe CMD-OVA conjugate can effectively deliver the antigen to the tumor site, implying its high potential as the antigen carrier for cancer immunotherapy.

High Indoleamine 2,3-Dioxygenase Is Correlated With Microvessel Density and Worse Prognosis in Breast Cancer.

Indoleamine 2,3-dioxygenase (IDO), which catalyzes the breakdown of the essential amino acid tryptophan into kynurenine, is understood to have a key role in cancer immunotherapy. IDO has also received more attention because of its non-immune functions including regulating angiogenesis. The purpose of this study was to investigate the effects of IDO on microvessel density (MVD), and to explore its prognostic role in breast cancer. We showed IDO expression was positively correlated with MVD labeled by CD105 (MVD-CD105) rather than MVD labeled by CD31 (MVD-CD31) in breast cancer specimens. Both IDO expression and MVD-CD105 level were associated with initial TNM stage, histological grade, and tumor-draining lymph nodes (TDLNs) metastasis in breast cancer. In the prognostic analysis, TDLNs metastasis, an advanced TNM stage (III) and high histological grade (III) significantly predicted shorter survival in univariate analysis. Concentrating on IDO and MVD, the patients with IDO expression or high MVD level had poorer prognosis compared with no IDO expression [P = 0.047 for progress-free survival (PFS)] and low MVD level (P = 0.019 for OS); the patients with IDO expression and high MVD level had a tendency with shorter overall survival when compared with non IDO expression, low MVD level, or both (P = 0.062 for OS). In multivariate analysis, an advanced TNM stage (III) was significantly associated with shorter 5-year survival rate of PFS (HR: 0.126, 95% CI: 0.024–0.669, P = 0.015). In order to verify the phenomenon of IDO promoting angiogenesis, we contained the study in vitro. We detected the expression of IDO mRNA in breast cancer cell lines and measured the concentration of tryptophan and kynurenine in the supernatants of MCF-7 by high performance liquid chromatography. The ratio of Kyn and trp (kyn/trp) was calculated to estimate IDO-enzyme activity. MCF-7 cells, which produce high level of IDO and metabolize tryptophan, promoted human umbilical vein endothelial cells (HUVEC) proliferation significantly in co-culture system. Meanwhile IDO could upregulate the expression of CD105 in HUVEC, which was downregulated after adding IDO inhibitor, 1-methyl-d-trytophan. These results suggest that IDO could promote angiogenesis in breast cancer, providing a novel, potentially effective molecular or gene therapy target for angiogenesis inhibition in the future.

Polymeric nanoparticles encapsulating novel TLR7/8 agonists as immunostimulatory adjuvants for enhanced cancer immunotherapy

Cytotoxic T lymphocytes (CTLs) play a major role in cancer immunotherapy because of their ability to directly kill tumor cells and secrete tumor suppressive cytokines. Anticancer vaccines aim to provoke tumor-specific CTL responses, which require activation of antigen presenting cells (APCs) including dendritic cells (DCs) and macrophages. Therefore, a potent immunostimulatory adjuvant capable of activating APCs is an essential component of anticancer vaccines. In this study, we introduce novel TLR 7/8 bi-specific agonists that significantly enhance cytokine secretion compared to TLR7 mono-selective compounds. Encapsulation of these TLR 7/8 agonists in poly(lactide-co-glycolide) (PLGA) nanoparticles increased the co-stimulatory molecule expression and antigen presentation via MHC I by DCs compared to the soluble agonist. When administered subcutaneously, these nanoparticles migrated to draining lymph node and triggered DC activation and expansion. This lead to expansion of antigen-specific CD8 T cells and enhanced CTL response, which resulted in significant prophylactic and therapeutic efficacy in melanoma, bladder and renal cell carcinoma tumor models. Importantly, our studies demonstrate significant reductions in systemic metastasis with the nanoparticle vaccine. Our results suggest novel TLR 7/8 agonist-encapsulated nanoparticles are potent immunostimulatory adjuvants for cancer immunotherapy.

Neuroblastoma Patients' KIR and KIR-Ligand Genotypes Influence Clinical Outcome for Dinutuximab-based Immunotherapy: A Report from the Children's Oncology Group.

Purpose: In 2010, a Children's Oncology Group (COG) phase III randomized trial for patients with high-risk neuroblastoma (ANBL0032) demonstrated improved event-free survival (EFS) and overall survival (OS) following treatment with an immunotherapy regimen of dinutuximab, GM-CSF, IL2, and isotretinoin compared with treatment with isotretinoin alone. Dinutuximab, a chimeric anti-GD2 monoclonal antibody, acts in part via natural killer (NK) cells. Killer immunoglobulin-like receptors (KIR) on NK cells and their interactions with KIR-ligands can influence NK cell function. We investigated whether KIR/KIR-ligand genotypes were associated with EFS or OS in this trial.Experimental Design: We genotyped patients from COG study ANBL0032 and evaluated the effect of KIR/KIR-ligand genotypes on clinical outcomes. Cox regression models and log-rank tests were used to evaluate associations of EFS and OS with KIR/KIR-ligand genotypes.Results: In this trial, patients with the "all KIR-ligands present" genotype as well as patients with inhibitory KIR2DL2 with its ligand (HLA-C1) together with inhibitory KIR3DL1 with its ligand (HLA-Bw4) were associated with improved outcome if they received immunotherapy. In contrast, for patients with the complementary KIR/KIR-ligand genotypes, clinical outcome was not significantly different for patients who received immunotherapy versus those receiving isotretinoin alone.Conclusions: These data show that administration of immunotherapy is associated with improved outcome for neuroblastoma patients with certain KIR/KIR-ligand genotypes, although this was not seen for patients with other KIR/KIR-ligand genotypes. Further investigation of KIR/KIR-ligand genotypes may clarify their role in cancer immunotherapy and may enable KIR/KIR-ligand genotyping to be used prospectively for identifying patients likely to benefit from certain cancer immunotherapy regimens. Clin Cancer Res; 24(1); 189-96. ©2017 AACRSee related commentary by Cheung and Hsu, p. 3.

Potentials of interleukin-27 (IL-27) as an immunotherapeutic cytokine in cancer therapy

Cancer immunotherapy using cytokines has been sought as an alternative therapeutic approach for treating cancers. Besides remarkable immunoregulatory properties, interleukin (IL)-27 has recently been shown to possess promising anticancer functions; hence, its potential roles in cancer immunotherapy. Although proven to be effective against cancer cell growth and angiogenesis, given its dual immune-regulating functions (pro-inflammatory and anti-inflammatory), the use of IL-27 as a cancer immunotherapeutic cytokine could possibly be a two-edged sword without meticulous and thorough research. This mini-review mainly discusses the functions and future prospects of IL-27 as an effective anticancer cytokine. Hopefully, it imparts useful insights into the potential applications of IL-27 in cancer immunotherapy

Synergy of Dendritic Cell Vaccines and Avasimibe in Treatment of Head and Neck Cancer in Mice.

BackgroundThe main purpose of this study was to explore the antitumor effect and mechanisms of ACAT1 inhibitor combined with CSCs-DC vaccine.Material/MethodsWe isolated HNSCC CSCs and gained CSCs antigens, then used CSCs antigens to load dendritic cells (DC) and generated a CSCs-DC vaccine. We treated mice after surgical excision of established SCC7 tumors with CSCs-DC vaccine and/or ACAT1 inhibitor, and recorded local tumor relapse and host survival. T cells and B cells were harvested from mice treated with CSCs-DC vaccine and/or ACAT1 inhibitor. We tested antibody production and the death rate of CSCs killed by T cells.ResultsThe tumors in the combined treatment group were smaller than in all other groups (P<0.01). The average survival time of the combined treatment group was 82 days and was the longest of all groups. Analysis of IgG levels secreted by B cell and CTL activity in spleens of mice found that results of the combined treatment group were the highest, and the results of the CSCs-DC group were lower than in the combined treatment group. The ACAT1 inhibitor group results were lower than in the CSCs-DC group and the combined treatment group results, but higher than in the PBS group, and the difference was statistically significant.ConclusionsACAT1 inhibitor enhanced the therapeutic effect of CSCs-DC vaccine in the treatment of the mouse HNSCC postoperative recurrence model. ACAT1 may play an important role in cancer immunotherapy.

Abstract 2144: A novel method for high-throughput discovery of neo-antigens and corresponding T-cell receptors

Abstract Immunotherapies that boost the ability of endogenous T cells to destroy cancer cells have demonstrated therapeutic efficacy in several human malignancies. Cytotoxic T cells actively recognize peptide antigens, which are displayed on major histocompatibility complexes (MHCs) on the surface of the malignant cells, to play a central role in cancer immunotherapy. However, efficient methods for identifying the tumor antigens and the corresponding T cell receptors are still limited. We report here a DNA-barcode nanoparticle and microfluidics-based method to sort and enumerate neoantigen-specific T cells, at an unprecedented level of sensitivity. The method also permits the matching of a single neoantigen to a specific CD8+ T cell with the TCR a/b gene sequence. The resultant information informs an immunotherapy regimen that is specific for that patient, which can be used to custom-design effective ACT therapies. Citation Format: Songming Peng, Jesse Zaretsky, Michael T. Bethune, Alice Hsu, David Baltimore, Antoni Ribas, James Heath. A novel method for high-throughput discovery of neo-antigens and corresponding T-cell receptors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2144. doi:10.1158/1538-7445.AM2017-2144

Mithramycin-loaded mPEG-PLGA nanoparticles exert potent antitumor efficacy against pancreatic carcinoma.

Previous studies have shown that mithramycin A (MIT) is a promising candidate for the treatment of pancreatic carcinoma through inhibiting transcription factor Sp1. However, systemic toxicities may limit its clinical application. Here, we report a rationally designed formulation of MIT-loaded nanoparticles (MIT-NPs) with a small size and sustained release for improved passive targeting and enhanced therapeutic efficacy. Nearly spherical MIT-NPs with a mean particle size of 25.0±4.6 nm were prepared by encapsulating MIT into methoxy poly(ethylene glycol)-block-poly(d,l-lactic-co-glycolic acid) (mPEG-PLGA) nanoparticles (NPs) with drug loading of 2.11%±0.51%. The in vitro release of the MIT-NPs lasted for >48 h with a sustained-release pattern. The cytotoxicity of MIT-NPs to human pancreatic cancer BxPC-3 and MIA Paca-2 cells was comparable to that of free MIT. Determined by flow cytometry and confocal microscopy, the NPs internalized into the cells quickly and efficiently, reaching the peak level at 1–2 h. In vivo fluorescence imaging showed that the prepared NPs were gradually accumulated in BxPC-3 and MIA Paca-2 xenografts and retained for 168 h. The fluorescence intensity in both BxPC-3 and MIA Paca-2 tumors was much stronger than that of various tested organs. Therapeutic efficacy was evaluated with the poorly permeable BxPC-3 pancreatic carcinoma xenograft model. At a well-tolerated dose of 2 mg/kg, MIT-NPs suppressed BxPC-3 tumor growth by 96%. Compared at an equivalent dose, MIT-NPs exerted significantly higher therapeutic effect than free MIT (86% versus 51%, P<0.01). Moreover, the treatment of MIT and MIT-NPs reduced the expression level of oncogene c-Myc regulated by Sp1, and notably, both of them decreased the protein level of CD47. In summary, the novel formulation of MIT-NPs shows highly therapeutic efficacy against pancreatic carcinoma xenograft. In addition, MIT-NPs can downregulate CD47 expression, implying that it might play a positive role in cancer immunotherapy.

P2.01-067 The Relevance of CEA and CYFRA21-1 as Predictive Factors in Nivolumab Treated Advanced Non-Small Cell Lung Cancer (NSCLC) Patients

CEA, CYFRA21-1 and NSE are tumor markers acknowledged as useful predictors of response to chemotherapy for advanced adenocarcinoma, squamous and small-cell lung cancer, respectively. However, their role in cancer immunotherapy needs to be investigated. We analyzed 56 patients with advanced NSCLC treated with nivolumab (3 mg/kg) every 14 days within a single-institutional translational research study. Blood samples were collected at baseline and at each cycle up to 5 cycles, and then every two cycles. All patients underwent a CT-scan every 4 cycles and responses were classified according to RECIST and Immune-Related Response Criteria (irRC). The serum level of CEA was measured with a Chemiluminescent Microparticle Immunoassay while CYFRA21-1 and NSE with an Immuno Radiometric Assay. The markers levels at baseline and after 4 cycles were used to analyze the relationship between their median variation and the objective response rate (ORR). The performance of tumor markers in predicting ORR was analyzed by ROC analysis and a reduction of 20% was used as cut-off level. Forty-eight patients were evaluated: median age: 71 years (44-85); male/female: 73%/27%; current or former smokers: 87.5%; non-squamous/squamous histology: 79%/21%. Baseline median levels were 4.8 ng/ml for CEA, 3.47 ng/ml for CYFRA21-1 and 7.51 ng/ml for NSE. At baseline, values over the upper normal limit of CEA, CYFRA21-1 and NSE were detected in 23 (48%), 26 (54%), and 7 (14%) patients respectively. Significant differences were observed between responders and non-responders and CEA variation (-9% vs.+41%, p=0.003 for RECIST; -10% vs.+31%, p=0.015 for irRC), CYFRA21-1variation (-39% vs.+92%, p<0.001 for RECIST; -35% vs.+72%, p=0.003 for irRC) and NSE variation (-30% vs.+23%, p=0.005 for RECIST; -23% vs.+36%, p=0.004 for irRC). Significant correlations were observed between CEA and CYFRA21-1 decrease with RECIST or irRC: with RECIST, a decrease of 20% of CEA was achieved in 43% of responders and in 8% of non-responders (p=0.013), while a decrease of 20% of CYFRA21-1 occurred in 67% of responders and in 8% of non-responders (p<0.007). With irRC, a decrease of 20% of CEA was achieved in 42% of responders and in 9% of non-responders (p=0.018), while a decrease of 20% of CYFRA21-1 occurred in 58% of responders and in 14% of non-responders (p=0.002). Multivariate analysis confirmed the positive association between CYFRA 21-1 (≤20%) and ORR (RECIST: p=0.004; irRC: p=0.016). The reduction in serum level of CEA and CYFRA21-1 might be a reliable biomarker to predict immunotherapy efficacy in NSCLC patients.

Natural Killer Cells: A Review on Their Role in Cancer Immunotherapy

Natural Killer Cells: A Review on Their Role in Cancer Immunotherapy

Immuno-Oncology: The Third Paradigm in Early Drug Development.

Clinical researchers in oncology face the difficulty of developing new drugs for treating cancer patients. This challenge nowadays extends towards new horizons since a high number of drugs are developed in each of the three paradigms: classical cytotoxics, new targeted agents, and emergent immunotherapeutic approaches. Over the last decade, there has been an unstoppable progress in this third paradigm, to the extent that in 2013 immunotherapy was granted the scientific breakthrough of the year. However, the novel mechanisms of action of these immunotherapeutic agents entail a whole new series of concepts, resulting in a number of unresolved questions to which clarification is crucial for their success: establishment of accurate preclinical models able to predict human toxicities, better selection of candidate populations, finding and validation of predictive biomarkers, definition of suitable endpoints, improvements in first-in-human study designs, proposal of more accurate radiological response criteria, management of novel immune-related toxicities and development of combinations based on a biological rationale. In this article, we review the major challenges to overcome in forthcoming years. The final role of immunotherapy in cancer will be determined by our capacity to shed some light on some of these key points.

Abstract A074: Selective Inhibition of HDAC6 augments T-cell central memory and enhances anti-tumor functions: Implications in TIL therapy

Abstract Histone deacetylases (HDACs) are a family of epigenetic modulators responsible for regulating gene expression. As key players in orchestrating both tumor and immune responses, HDACs have received attention for their possible role in cancer immunotherapy. While pan-HDAC inhibitors directly impact tumor growth, their broad targeting can be detrimental to the immune system. In this sense, HDAC selective inhibition becomes attractive as a strategy to minimize off-target effects. Here a novel role of targeting HDAC6 in T-cells with potential implications for melanoma immunotherapy is explored. Adoptive T-cell therapy is an effective treatment for metastatic melanoma, reaching objective clinical responses in half of patients undergoing tumor infiltration lymphocyte (TIL) therapy. However, lack of persistence of reactive T-cells is a major reason why patients fail to sustain long-term responses to treatment. The presence of T-cell memory populations is associated with prolonged responses to TIL. Herein we have shown that HDAC6-selective inhibition by ricolinostat increased the central memory phenotype of human CD4 and CD8 T-cells (p&amp;lt;0.01 and p&amp;lt;0.05, respectively), as indicated by CD45RO, CD45RA, CD62L and/or CCR7 surface markers. While a decrease in the naïve, effector and effector memory subsets occurred, no differences in cell viability were observed. Accordingly, similar ricolinostat-induced central memory enhancement was seen in CD4 and CD8 T-cells from the peripheral blood of melanoma patients (p&amp;lt;0.01 and p&amp;lt;0.05, respectively). Ultimately, ricolinostat led to accumulation of a central memory phenotype for TIL derived from various cell preparations (e.g. tumor digest, pre- and post-rapid expansion in vitro), with p values &amp;lt;0.05. Intriguingly, Th2 cytokine production (i.e. IL-4 p&amp;lt;0.01, IL-6 p&amp;lt;0.001 and IL-10) was impaired in T-cells from melanoma patients treated with ricolinostat, while no differences occurred on IL-2, IFNg, TNF or IL-17a secretion. Functionally, TILs isolated from patient-derived melanoma fragments cultured in the presence of ricolinostat exhibited increased proportion of CD8 T-cells producing IFNg and CD107a cytolytic molecules (50% vs 35%, p&amp;lt;0.05). Moreover, no negative impact on T-cell viability or proliferation was observed following ricolinostat treatment. No detrimental effects were observed in the yield of TIL from melanoma fragments. Cytotoxicity in vitro was also evaluated. Relative to a melanoma only control group, ricolinostat pre-treatment of TILs or concomitantly with tumor cells induced 70% killing of HLA matched melanoma cells, while control-treated TILs resulted in 50% cell death. In vivo, adoptive transfer of rocilinostat-treated murine T-cells improved the anti-melanoma effect in a B16F10 model (day 25 mean tumor volume 800 vs. 2200 cubic mm). Ex vivo characterization of the memory T-cell distribution in the lymph nodes demonstrated increased CD44+CD62L+ T-cells upon HDAC6-selective inhibition (CD8+ 32.8% vs 21.8%; CD4+ 4.71% vs 2.3%), suggesting a role of HDAC6 in the formation or distribution of memory CD4+ and CD8+ T-cells. The results suggest a positive impact of HDAC6-selective inhibition on TIL therapy and the resulting anti-melanoma response in vivo. While further dissection of molecular mechanism(s) is essential, the data described provide a rationale for targeting HDAC6 to augment melanoma immunotherapy. Citation Format: Andressa Sodre Laino, David M. Woods, Amod Sarnaik, Jeffrey Weber, Eduardo M. Sotomayor. Selective Inhibition of HDAC6 augments T-cell central memory and enhances anti-tumor functions: Implications in TIL therapy. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A074.

Integrated Akt/PKB signaling in immunomodulation and its potential role in cancer immunotherapy.

T cell development and maturation involve a variety of defined and coordinated developmental stages under the control of a variety of signaling networks. They function as the major mediator in cell-based immunity that defends against pathogen infections and executes immune surveillance against tumor cells. Protein kinase B (PKB, also called Akt) is central to multiple signaling pathways and transduces extracellular signals to dictate cellular responses towards proliferation, migration, anti-apoptosis, and maintenance of metabolic homeostasis. Although the prosurvival function of PKB was thought to be responsible for most of the functions regulated by PKB, emerging evidence has started to dissect its role in immunomodulation. More importantly, hyperactivation of PKB in cancer stroma frequently occurs in patients treated clinically with targeted cancer therapies, where it acts as a key mediator involved in the trapping of host immune cells in the vicinity of tumors, which supports cancer cell invasion and the escape of cancer cells from host immune surveillance. Encouragingly, recent studies have shown that inhibition of PKB improves the recognition of cancer cells by the host immune system, indicating a potential clinical strategy to rekindle the suppressed host immune response through the specific targeting of PKB. In this review, we explore how PKB signaling contributes to T cell development and cellular immune responses and discuss the mechanistic roles that PKB plays in the creation of immunosuppressive conditions and the escaping of immune recognition in the microenvironment of cancer.

Neuroblastoma killing properties of Vδ2 and Vδ2-negative γδT cells following expansion by artificial antigen-presenting cells.

The majority of circulating human γδT lymphocytes are of the Vγ9Vδ2 lineage, and have T-cell receptor (TCR) specificity for nonpeptide phosphoantigens. Previous attempts to stimulate and expand these cells have therefore focused on stimulation using ligands of the Vγ9Vδ2 receptor, whereas relatively little is known about variant blood γδT subsets and their potential role in cancer immunotherapy. To expand the full repertoire of γδT without bias toward specific TCRs, we made use of artificial antigen-presenting cells loaded with an anti γδTCR antibody that promoted unbiased expansion of the γδT repertoire. Expanded cells from adult blood donors were sorted into 3 populations expressing respectively Vδ2 TCR chains (Vδ2(+)), Vδ1 chains (Vδ1(+)), and TCR of other δ chain subtypes (Vδ1(neg)Vδ2(neg)). Both freshly isolated and expanded cells showed heterogeneity of differentiation markers, with a less differentiated phenotype in the Vδ1 and Vδ1(neg)Vδ2(neg) populations. Expanded cells were largely of an effector memory phenotype, although there were higher numbers of less differentiated cells in the Vδ1(+) and Vδ1(neg)Vδ2(neg) populations. Using neuroblastoma tumor cells and the anti-GD2 therapeutic mAb ch14.18 as a model system, all three populations showed clinically relevant cytotoxicity. Although killing by expanded Vδ2 cells was predominantly antibody dependent and proportionate to upregulated CD16, Vδ1 cells killed by antibody-independent mechanisms. In conclusion, we have demonstrated that polyclonal-expanded populations of γδT cells are capable of both antibody-dependent and -independent effector functions in neuroblastoma.

Antiviral and Antitumor T-cell Immunity in Patients Treated with GM-CSF–Coding Oncolytic Adenovirus

Multiple injections of oncolytic adenovirus could enhance immunologic response. In the first part of this article, the focus was on immunologic aspects. Sixty patients previously naïve to oncolytic virus and who had white blood cells available were treated. Thirty-nine of 60 were assessed after a single virus administration, whereas 21 of 60 received a "serial treatment" consisting of three injections within 10 weeks. In the second part, we focused on 115 patients treated with a granulocyte macrophage colony-stimulating factor (GM-CSF)-coding capsid chimeric adenovirus, CGTG-102. Following serial treatment, both increase and decrease in antitumor T cells in blood were seen more frequently, findings which are compatible with induction of T-cell immunity and trafficking of T cells to tumors, respectively. Safety was good in both groups. In 115 patients treated with CGTG-102 (Ad5/3-D24-GMCSF), median overall survival was 111 days following single and 277 days after serial treatment in nonrandomized comparison. Switching the virus capsid for avoiding neutralizing antibodies in a serial treatment featuring three different viruses did not impact safety or efficacy. A correlation between antiviral and antitumor T cells was seen (P = 0.001), suggesting that viral oncolysis can result in epitope spreading and breaking of tumor-associated immunologic tolerance. Alternatively, some patients may be more susceptible to induction of T-cell immunity and/or trafficking. These results provide the first human data linking antiviral immunity with antitumor immunity, implying that oncolytic viruses could have an important role in cancer immunotherapy.

Enhanced cancer immunotherapy using nanoparticle-based modulation of SOCS1 genes in dendritic cells (P4242)

Abstract Although dendritic cells have important roles in cancer immunotherapy, their therapeutic efficiencies were limited due to the presence of immunosuppressive factors. Here, we report the fabrication and use of polymer nanoparticles for the simultaneous delivery of antigens and small interference RNA (siRNA) of immune suppressor genes into dendritic cells. The polymer nanoparticles containing ovalbumin (OVA, as a model antigen) and siRNA of suppressor of cytokine signaling 1 (SOCS1) were fabricated by double emulsion solvent evaporation method. The encapsulation of siRNA was about 57.6 % when OVA was present during the preparation, while that was only 2 % without the OVA. The polymer nanoparticles containing OVA and siRNA of SOCS1 were efficiently taken up by the dendritic cells and showed no detectable toxicity. The knockdown of SOCS1 genes in dendritic cells induced pro-inflammatory and anti-inflammatory cytokine expression. The polymer nanoparticles are expected to be potent nanotechnology platform for targeted delivery of siRNA and antigens into dendritic cells, and use as CD8+ T cells-based cancer immunotherapy.

Heat shock proteins enriched-promastigotes of Leishmania major inducing Th2 immune response in BALB/c mice.

Heat shock proteins (HSP) are highly conserved molecules with many immunological functions. They are highly immunogenic with important role in cancer immunotherapy and in vaccine development against infectious diseases. As adjuvant, HSP can augment the immunogenicity of weak antigens and can stimulate antigen presenting cells. Although vaccines have been successful for many infectious diseases, progress in leishmaniasis has not been achieved. In this report, the protective effect of HSP-enriched soluble leishmania antigen (SLA) was determined. BALB/c mice were immunized 3× with HSP-enriched SLA and SLA alone and 10 days after final boost. They were infected with 106 stationary phase promastigote of Leishmania major and immunological responses were followed until nine weeks. No significant differences were observed in lymphocyte proliferation, footpad swelling, parasite burden, nitric oxide or IL-12 cytokine between HSP-enriched or SLA groups. Although the levels of IFN-γ, IL-4, TGF-β, IgG1 and IgG2b were increased in both groups, IFN-γ was significantly higher in SLA group and IgG2a in HSP-enriched SLA. These results indicate that HSP direct the immune system towards Th2 pattern and does not have protective role in L. major infection.

Changes in specialized blood vessels in lymph nodes and their role in cancer metastasis

BackgroundHigh endothelial venules (HEV) have been recognized to play a role in metastasis by its changes seen in the cancer microenvironment of lymph nodes (LN) and solid cancers. Squamous cell carcinoma (SCC) of the tongue is a prevalent tumor of the head and neck region with high propensity for LN metastasis. The extent of LN metastasis is the most reliable adverse prognostic factor. Primary tumors can induce vasculature reorganization within sentinel LN before the arrival of tumor cells and HEV represents these remodelled vessels. This study aims to evaluate the cancer induced vascular changes in regional lymph nodes (LN) of patients by studying the morphological and functional alterations of HEV and its correlation with clinical outcome and pathological features.MethodsThis study was based on 65 patients with SCC tongue who underwent primary surgical treatment including neck dissection. The patients were categorized into 2 groups based on the presence of malignancy in their cervical lymph nodes. A review of the patients' pathological and clinical data was performed from a prospective database. Immunohistochemical staining of the tissue blocks for HEV and high-power-field image analysis were performed and analyzed with correlation to the patients' clinical and pathological features.ResultsThe total number of HEV was found to be significantly associated to disease-free interval. There was a similar association comparing the HEV parameters to overall survival. The density of abnormal HEV was significantly higher in patients with established metastases in their lymph nodes and HEV was shown to be a better prognosis factor than conventional tumor staging. The HEV morphological metamorphosis demonstrates a spectrum that correlates well with disease progression and clinical outcome.ConclusionsThe results suggest that the HEV displays a spectrum of morphological changes in the presence of cancer and LN metastasis, and that HEV is possibly involved in the process of cancer metastasis. We revealed the relationship of HEV and their metamorphosis in pre-metastatic and metastatic environments in regional lymph nodes of tongue cancer patients in relation to clinical outcomes. The significant observation of modified dilated HEV containing red blood cells in lymph nodal basin of a cancer suggests the shifting of its function from one primarily of immune response to that of a blood carrying vessel. It also demonstrated potential prognostic value. More studies are needed to elucidate its potential role in cancer immunotherapy and as a potential novel therapeutic approach to preventing metastasis by manipulating the remodelling processes of HEV.

Recent Advances in Cancer Vaccines - An Update

Cancer related deaths have shown a progressive increase over the past decade and the newer cases of cancers are estimated to rise in 2030. The current treatment modalities available for cancer are highly toxic, impair quality of life and develop resistance with course of time. Thus, there is a growing necessity for the prevention and cure of cancer related morbidity and mortality. One of the promising approaches for cancer prevention could be immunization with specific vaccines. The latest advances in immunology have led to the development of effective cancer vaccines to enhance immunity against tumour cells. Moreover, the occurrence of cancer with infectious agents like Hepatitis B virus (HBV) and Human Papilloma virus (HPV) as well as their prevention with specific cancer vaccines has further confirmed the role of immunotherapy in cancer. Though prophylactic vaccines are found to be more successful in cancer prevention, in the present scenario most of the vaccines under development are therapeutic cancer vaccines. Cancer vaccines stimulate the immune system and attack specific cancer cells without harming the normal cells. The major cancer vaccines under development to target tumour cells includes antigen vaccines, whole cell tumour vaccines, dendritic cell vaccine, viral vectors, DNA vaccines and idiotype vaccines. Apart from this, measures to produce patient-specific cancer vaccines from patients own tumour cells and a "universal" vaccine to provide immunity against cancer cells of any origin are being investigated. Hence this review gives an overview of various strategies involved in the development of cancer vaccines and the currently approved vaccines available for the prevention of cancer.

Dendritic Cells Loaded With mRNA Encoding Full-length Tumor Antigens Prime CD4+ and CD8+ T Cells in Melanoma Patients

It is generally thought that dendritic cells (DCs) loaded with full-length tumor antigen could improve immunotherapy by stimulating broad T-cell responses and by allowing treatment irrespective of the patient's human leukocyte antigen (HLA) type. To investigate this, we determined the specificity of T cells from melanoma patients treated with DCs loaded with mRNA encoding a full-length tumor antigen fused to a signal peptide and an HLA class II sorting signal, allowing presentation in HLA class I and II. In delayed-type hypersensitive (DTH)-biopsies and blood, we found functional CD8(+) and CD4(+) T cells recognizing novel treatment-antigen-derived epitopes, presented by several HLA types. Additionally, we identified a CD8(+) response specific for the signal peptide incorporated to elicit presentation by HLA class II and a CD4(+) response specific for the fusion region of the signal peptide and one of the antigens. This demonstrates that the fusion proteins contain newly created immunogenic sequences and provides evidence that ex vivo-generated mRNA-modified DCs can induce effector CD8(+) and CD4(+) T cells from the naive T-cell repertoire of melanoma patients. Thus, this work provides definitive proof that DCs presenting the full antigenic spectrum of tumor antigens can induce T cells specific for novel epitopes and can be administered to patients irrespective of their HLA type.