Chemo-immunotherapy mediates durable cure of orthotopic KrasG12D/p53-/- pancreatic ductal adenocarcinoma

Single-cell analysis reveals cellular and molecular factors counteracting HPV-positive oropharyngeal cancer immunotherapy outcomes

BACKGROUND

Oropharyngeal squamous cell carcinoma (OPSCC) induced by human papillomavirus (HPV-positive) is associated with better clinical outcomes than HPV-negative OPSCC. However, the clinical benefits of immunotherapy in patients with HPV-positive OPSCC remain unclear.

METHODS

To identify the cellular and molecular factors that limited the benefits associated with HPV in OPSCC immunotherapy, we performed single-cell RNA (n=20) and T-cell receptor sequencing (n=10) analyses of tonsil or base of tongue tumor biopsies prior to immunotherapy. Primary findings from our single-cell analysis were confirmed through immunofluorescence experiments, and secondary validation analysis were performed via publicly available transcriptomics data sets.

RESULTS

We found significantly higher transcriptional diversity of malignant cells among non-responders to immunotherapy, regardless of HPV infection status. We also observed a significantly larger proportion of CD4+ follicular helper T cells (Tfh) in HPV-positive tumors, potentially due to enhanced Tfh differentiation. Most importantly, CD8+ resident memory T cells (Trm) with elevated KLRB1 (encoding CD161) expression showed an association with dampened antitumor activity in patients with HPV-positive OPSCC, which may explain their heterogeneous clinical outcomes. Notably, all HPV-positive patients, whose Trm presented elevated KLRB1 levels, showed low expression of CLEC2D (encoding the CD161 ligand) in B cells, which may reduce tertiary lymphoid structure activity. Immunofluorescence of HPV-positive tumors treated with immune checkpoint blockade showed an inverse correlation between the density of CD161+ Trm and changes in tumor size.

CONCLUSIONS

We found that CD161+ Trm counteracts clinical benefits associated with HPV in OPSCC immunotherapy. This suggests that targeted inhibition of CD161 in Trm could enhance the efficacy of immunotherapy in HPV-positive oropharyngeal cancers.

TRIAL REGISTRATION NUMBER

NCT03737968.

Innate and adaptive immune-directed tumour microenvironment in pancreatic ductal adenocarcinoma

One of the most deadly and aggressive cancers in the world, pancreatic ductal adenocarcinoma (PDAC), typically manifests at an advanced stage. PDAC is becoming more common, and by the year 2030, it is expected to overtake lung cancer as the second greatest cause of cancer-related death. The poor prognosis can be attributed to a number of factors, including difficulties in early identification, a poor probability of curative radical resection, limited response to chemotherapy and radiotherapy, and its immunotherapy resistance. Furthermore, an extensive desmoplastic stroma that surrounds PDAC forms a mechanical barrier that prevents vascularization and promotes poor immune cell penetration. Phenotypic heterogeneity, drug resistance, and immunosuppressive tumor microenvironment are the main causes of PDAC aggressiveness. There is a complex and dynamic interaction between tumor cells in PDAC with stromal cells within the tumour immune microenvironment. The immune suppressive microenvironment that promotes PDAC aggressiveness is contributed by a range of cellular and humoral factors, which itself are modulated by the cancer. In this review, we describe the role of innate and adaptive immune cells, complex tumor microenvironment in PDAC, humoral factors, innate immune-mediated therapeutic advances, and recent clinical trials in PDAC.

Immunomodulatory proteins from hookworms reduce cardiac inflammation and modulate regulatory responses in a mouse model of chronic Trypanosoma cruzi infection

Introduction

Hookworms are parasitic helminths that secrete a variety of proteins that induce anti-inflammatory immune responses, stimulating increased CD4 + Foxp3+ regulatory T cells and IL-10 production. Hookworm-derived recombinant proteins AIP-1 and AIP-2 have been shown to reduce inflammation in mouse models of inflammatory bowel disease and inflammatory airway disease by inducing CD4+Foxp3+ cells and IL-10 production. In contrast, chronic infection with the protozoal parasite Trypanosoma cruzi, the causative agent of Chagas disease, leads to chronic inflammation in tissues. Persistence of the parasites in tissues drives chronic low-grade inflammation, with increased infiltration of inflammatory cells into the heart, accompanied by increased production of inflammatory cytokines. There are no current antiparasitic drugs that effectively reduce or prevent chronic myocarditis caused by the onset of Chagas disease, thus new therapies are urgently needed. Therefore, the impact of AIP-1 and AIP-2 on myocarditis was investigated in a mouse model of chronic T. cruzi infection.

Methods

Female BALB/c mice infected with bioluminescent T. cruzi H1 strain trypomastigotes for 70 days were treated once daily for 7 days with 1mg/kg AIP-1 or AIP-2 protein by intraperitoneal injection. Control mice were left untreated or treated once daily for 14 days with 25mg/kg aspirin in drinking water. At 84 days of infection, splenocytes, cardiac tissue and serum were collected for evaluation.

Results

Treatment with both AIP-1 and AIP-2 proteins significantly reduced cardiac cellular infiltration, and reduced cardiac levels of IFNγ, IL-6 and IL-2. AIP-2 treatment reduced cardiac expression of COX-2. Further, while incubation with AIP-1 and AIP-2 proteins did not induce a significant upregulation of an immunoregulatory phenotype in dendritic cells (DC), there was a modest upregulation of CD11c +CD11b+MHCII+SIRPα+ expression, suggesting a regulatory phenotype. Ex-vivo stimulation of splenocytes from the treatment groups with AIP-1 loaded DC induced reduced levels of cytotoxic and pro-inflammatory T cells, stimulation with AIP-2 loaded DC specifically induced enhanced levels of CD4+CD25+Foxp3+ regulatory T cells among treatment groups.

Discussion

All in vivo and in vitro results demonstrate that hookworm-derived AIP-1 and AIP-2 proteins reduce T. cruzi induced cardiac inflammation, possibly through multiple anti-inflammatory mechanisms.

RAS signaling and immune cells: a sinister crosstalk in the tumor microenvironment

The rat sarcoma virus (RAS) gene is the most commonly mutated oncogene in cancer, with about 19% of cancer patients carrying RAS mutations. Studies on the interaction between RAS mutation and tumor immune microenvironment (TIM) have been flourishing in recent years. More and more evidence has proved that RAS signals regulate immune cells' recruitment, activation, and differentiation while assisting tumor cells to evade immune surveillance. This review concluded the direct and indirect treatment strategies for RAS mutations. In addition, we updated the underlying mechanisms by which RAS signaling modulated immune infiltration and immune escape. Finally, we discussed advances in RAS-targeted immunotherapies, including cancer vaccines and adoptive cell therapies, with a particular focus on combination strategies with personalized therapy and great potential to achieve lasting clinical benefits.

Targeting the undruggable oncogenic KRAS: the dawn of hope

KRAS mutations are the drivers of various cancers, including non-small cell lung cancer, colon cancer, and pancreatic cancer. Over the last 30 years, immense efforts have been made to inhibit KRAS mutants and oncogenic KRAS signaling using inhibitors. Recently, specific targeting of KRAS mutants with small molecules revived the hopes for successful therapies for lung, pancreatic, and colorectal cancer patients. Moreover, advances in gene editing, protein engineering, and drug delivery formulations have revolutionized cancer therapy regimens. New therapies aim to improve immune surveillance and enhance antitumor immunity by precisely targeting cancer cells harboring oncogenic KRAS. Here, we review recent KRAS-targeting strategies, their therapeutic potential, and remaining challenges to overcome. We also highlight the potential synergistic effects of various combinatorial therapies in preclinical and clinical trials.

A subset of cytotoxic effector memory T cells enhances CAR T cell efficacy in a model of pancreatic ductal adenocarcinoma

In humans, the natural killer (NK) cell marker CD161 identifies several subsets of T cells, including a polyclonal CD8 αβ T cell receptor-expressing subset with characteristic specificity for tissue-localized viruses. This subset also displays enhanced cytotoxic and memory phenotypes. Here, we characterized this unique T cell subset and determined its potential suitability for use in chimeric antigen receptor (CAR) T cell therapy. In mice, gene expression profiling among the CD161-equivalent CD8⁺ T cell populations (CD8⁺NK1.1⁺) revealed substantial up-regulation of granzymes, perforin, killer lectin-like receptors, and innate signaling molecules in comparison to CD8⁺NK1.1^- T cells. Adoptive transfer of CD8⁺NK1.1⁺ cells from previously exposed animals offered substantially enhanced protection and improved survival against melanoma tumors and influenza infection compared to CD8⁺NK1.1^- cells. Freshly isolated human CD8⁺CD61⁺ T cells exhibited heightened allogeneic killing activity in comparison to CD8⁺CD61^- T cells or total peripheral blood mononuclear cells (PBMCs). To determine whether this subset might improve the antitumor efficacy of CAR T cell therapy against solid tumors, we compared bulk PBMCs, CD8⁺CD161^-, and CD8⁺CD161⁺ T cells transduced with a human epidermal growth factor receptor-2 (HER2)-specific CAR construct. In vitro, CD8⁺CD161⁺ CAR-transduced T cells killed HER2⁺ targets faster and with greater efficiency. Similarly, these cells mediated enhanced in vivo antitumor efficacy in xenograft models of HER2⁺ pancreatic ductal adenocarcinoma, exhibiting elevated expression of granzymes and reduced expression of exhaustion markers. These data suggest that this T cell subset presents an opportunity to improve CAR T cell therapy for the treatment of solid tumors.

CD8+CD161+ T-Cells: Cytotoxic Memory Cells With High Therapeutic Potential

NK1.1 and its human homolog CD161 are expressed on NK cells, subsets of CD4⁺ and CD8⁺ T cells, and NKT cells. While the expression of NK1.1 is thought to be inhibitory to NK cell function, it is reported to play both costimulatory and coinhibitory roles in T-cells. CD161 has been extensively studied and characterized on subsets of T-cells that are MR1-restricted, IL-17 producing CD4⁺ (T_H17 MAIT cells) and CD8⁺ T cells (Tc17 cells). Non-MAIT, MR1-independent CD161-expressing T-cells also exist and are characterized as generally effector memory cells with a stem cell like phenotype. Gene expression analysis of this enigmatic subset indicates a significant enhancement in the expression of cytotoxic granzyme molecules and innate like stress receptors in CD8⁺NK1.1⁺/CD8⁺CD161⁺ cells in comparison to CD8⁺ cells that do not express NK1.1 or CD161. First identified and studied in the context of viral infection, the role of CD8⁺CD161⁺ T-cells, especially in the context of tumor immunology, is still poorly understood. In this review, the functional characteristics of the CD161-expressing CD8⁺ T cell subset with respect to gene expression profile, cytotoxicity, and tissue homing properties are discussed, and application of this subset to immune responses against infectious disease and cancer is considered.

The synergistic tumor growth-inhibitory effect of probiotic Lactobacillus on transgenic mouse model of pancreatic cancer treated with gemcitabine

Pancreatic cancer is one of the most lethal and chemo-resistant cancers worldwide. Growing evidence supports the theory that the gut microbiota plays an essential role in modulating the host response to anti-cancer therapy. The present study aimed to explore the effect of probiotics as an adjuvant during chemotherapy for pancreatic cancer. An LSL-Kras^G12D/−-Pdx-1-Cre mouse model of pancreatic ductal adenocarcinoma (PDAC) was created to study the effects of using four-week multi-strain probiotics (Lactobacillus paracasei GMNL-133 and Lactobacillus reuteri GMNL-89) as an adjuvant therapy for controlling cancer progression. At 12 weeks of age, pancreatitis was induced in the mice by two intraperitoneal injection with caerulein (25 μg/kg 2 days apart). Over the next 4 weeks the mice were treated with intraperitoneal injections of gemcitabine in combination with the oral administration of probiotics. The pancreas was then harvested for analysis. Following caerulein treatment, the pancreases of the LSL-Kras^G12D/−-Pdx-1-Cre transgenic mice exhibited more extensive pancreatic intraepithelial neoplasia (PanIN) formation. Combined treatment with gemcitabine and probiotics revealed a lower grade of PanIN formation and a decrease in the expression of vimentin and Ki-67. Mice that received gemcitabine in combination with probiotics had lower aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Notably, the use of high-dose probiotics alone without gemcitabine also had an inhibitory effect on PanIN changes and serum liver enzyme elevation. These findings suggest that probiotics are able to make standard chemotherapy more effective and could help improve the patient’s tolerance of chemotherapy.

Deciphering the Role of Innate Immune NF-ĸB Pathway in Pancreatic Cancer

Simple Summary

Chronic inflammation is a major mechanism that underlies the aggressive nature and treatment resistance of pancreatic cancer. In many ways, the molecular mechanisms that drive chronic inflammation in pancreatic cancer are very similar to our body’s normal innate immune response to injury or invading microorganisms. Therefore, during cancer development, pancreatic cancer cells hijack the innate immune pathway to foster a chronically inflamed tumor environment that helps shield them from immune attack and therapeutics. While blocking the innate immune pathway is theoretically reasonable, untoward side effects must also be addressed. In this review, we comprehensively summarize the literature that describe the role of innate immune signaling in pancreatic cancer, emphasizing the specific role of this pathway in different cell types. We review the interaction of the innate immune pathway and cancer-driving signaling in pancreatic cancer and provide an updated overview of novel therapeutic opportunities against this mechanism.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers with no effective treatment option. A predominant hallmark of PDAC is the intense fibro-inflammatory stroma which not only physically collapses vasculature but also functionally suppresses anti-tumor immunity. Constitutive and induced activation of the NF-κB transcription factors is a major mechanism that drives inflammation in PDAC. While targeting this pathway is widely supported as a promising therapeutic strategy, clinical success is elusive due to a lack of safe and effective anti-NF-κB pathway therapeutics. Furthermore, the cell type-specific contribution of this pathway, specifically in neoplastic cells, stromal fibroblasts, and immune cells, has not been critically appraised. In this article, we highlighted seminal and recent literature on molecular mechanisms that drive NF-κB activity in each of these major cell types in PDAC, focusing specifically on the innate immune Toll-like/IL-1 receptor pathway. We reviewed recent evidence on the signaling interplay between the NF-κB and oncogenic KRAS signaling pathways in PDAC cells and their collective contribution to cancer inflammation. Lastly, we reviewed clinical trials on agents that target the NF-κB pathway and novel therapeutic strategies that have been proposed in preclinical studies.

MHC class I and II peptide homology regulates the cellular immune response

Mammalian immune responses are initiated by "danger" signals--immutable molecular structures known as PAMPs. When detected by fixed, germline encoded receptors, pathogen-associated molecular pattern (PAMPs) subsequently inform the polarization of downstream adaptive responses depending upon identity and localization of the PAMP. Here, we report the existence of a completely novel "PAMP" that is not a molecular structure but an antigenic pattern. This pattern--the incidence of peptide epitopes with stretches of 100% sequence identity bound to both dendritic cell (DC) major histocompatibility (MHC) class I and MHC class II--strongly induces T_H 1 immune polarization and activation of the cellular immune response. Inherent in the existence of this PAMP is the concomitant existence of a molecular sensor complex with the ability to scan and compare amino acid sequence identities of bound class I and II peptides. We provide substantial evidence implicating the multienzyme aminoacyl-tRNA synthetase (mARS) complex and its AIMp1 structural component as the key constituents of this complex. The results demonstrate a wholly novel mechanism by which T-helper (T_H ) polarization is governed and provide critical information for the design of vaccination strategies intended to provoke cell-mediated immunity.

Cancer vaccines: Targeting KRAS-driven cancers

Introduction: Mutant KRAS is a genetic driver of multiple cancers that has challenged clinical anti-cancer therapeutics in the last 3 decades. Neo-antigens encoded by KRAS mutations have been identified as tumor-specific with high immunogenicity and can be used to deliver precision cancer vaccines to promote anti-tumor immune responses. KRAS mutation-based cancer vaccines have produced encouraging preclinical and clinical results. Cancer vaccines represent a promising approach to treat KRAS-driven cancers.Areas covered: In this review, we summarize the development and progress of vaccines targeting KRAS and evaluate their potential benefits and obstacles in the current landscape of therapy for KRAS-driven cancers.Expert opinion: KRAS mutation-based cancer vaccines can induce immunogenicity in patients with KRAS-driven cancers. However, the mechanisms of tumor suppression including cellular and molecular factors within the tumor microenvironment may limit vaccine efficacy. Combining KRAS-driven therapeutic cancer vaccines with other methods and adjuvants can circumvent immunosuppression and promote therapeutic successes.

Dendritic cell immunotherapy induces anti-tumor effect in a transgenic mouse model of pancreatic ductal adenocarcinoma

The promise of dendritic cell (DC)-based immunotherapy has been established by two decades of translational research. However, long-term benefits of DC vaccination are reported in only scattered patients with pancreatic ductal adenocarcinoma (PDAC). Here we optimize DC vaccination and evaluate its safety and antitumor efficacy in the genetically engineered PDAC model (KrasLSL-G12D p53LSL-R172H Pdx-1-Cre (KPC mice)). KPC transgenic mice and orthotopic models using KPC cell lines were treated with DC vaccine via an intraperitoneal route. Tumor growth and microenvironment were dynamically monitored by magnetic resonance imaging (MRI). Histological analysis and flow cytometry were used to evaluate tumor-directed T cell immunity of these mice. DC vaccine via intraperitoneal injection suppressed tumor progression (P = 0.030) and significantly prolonged survival time (P = 0.028) in KPC mice. Vaccinated KPC mice displayed an increased antitumor T cell response indicated by a higher IFN-γ production (P = 0.016) and tumor-specific cytotoxicity (P = 0.027). Particularly, the mean apparent diffusion coefficient (ADC) values of KPC tumor calculated from diffusion weighted MRI (DW-MRI) were significantly higher in DC vaccine group than that in control group (P < 0.001). More interestingly, we observed that ADC positively correlated with fibrosis in KPC tumor (R2 = 0.463, P = 0.015). Our study demonstrated that the immunization with our improved DC vaccine can elicit a strong tumor-specific immune response and tumor suppression in PDAC.

A new strategy for enhancing antitumor immune response using dendritic cells loaded with chemo-resistant cancer stem-like cells in experimental mice model

BACKGROUND AND AIM

Cancer stem cells (CSCs) are rare cell population present in the tumor bulk that are thought to be the reason for treatment failure following chemotherapy in terms of their intrinsic chemo-resistance. Our study aimed to develop an effective therapeutic strategy to target chemo-resistant cancer stem - like cells population in solid Ehrlich carcinoma (SEC) mice model using dendritic cells (DCs) loaded with enriched tumor cells lysate bearing CSC-like phenotype as a vaccine.

MATERIALS AND METHODS

Ehrlich carcinoma cell line was exposed to different concentrations of cisplatin, doxorubicin, or paclitaxel. Drug treatment that resulted in drug surviving cells with the highest expression of CSCs markers (CD44⁺/CD24^-) was selected to obtain enriched cell cultures with resistant CSCs population. Dendritic cells were isolated from mice bone marrow, pulsed with enriched CSC lysate, analyzed and identified (CD11c, CD83 and CD86). SEC-bearing mice were treated with loaded or unloaded DCs either as single treatment or in combination with repeated low doses of cisplatin. IFN- γ serum level and p53gene expression in tumor tissues were determined by ELISA and real-time PCR, respectively.

RESULTS AND CONCLUSION

The results revealed that vaccination with CSC loaded DCs significantly reduced tumor size, prolonged survival rate, increased IFN-γ serum levels, and upregulated p53gene expression in SEC bearing mice. These findings were more evident and significant in the group co-treated with CSC-DC and cisplatin rather than other treated groups. This study opens the field for combining CSC-targeted immunotherapy with repeated low doses chemotherapy as an effective strategy to improve anticancer immune responses.

Dendritic cell vaccination plus low-dose doxorubicin for the treatment of spontaneous canine hemangiosarcoma

Angiosarcoma is a deadly neoplasm of the vascular endothelium. Metastatic disease is often present at diagnosis, and 5-year survival is only 10–35%. Although there exist no immunocompetent mouse models of angiosarcoma with which to study immune-based approaches to therapy, angiosarcoma is a major killer of companion dogs, responsible for up to 2% of all canine deaths in some susceptible breeds or an estimated 120,000 per year in the US. The canine disease (HSA) often presents in the spleen as acute hemoabdomen secondary to splenic rupture. Even if life-saving splenectomy is performed, median overall survival (OS) is only 48 days, and 1-year survival is negligible. Here we report the analysis of a pilot phase I open-label trial of chemo-immunotherapy performed on consecutively presenting splenectomized canines with histologically verified HSA. Subjects received an abbreviated course of low-dose doxorubicin plus alpha interferon and an autologous dendritic cell-therapy reported to enhance durable CD8⁺ memory. Disease was monitored monthly by abdominal ultrasound, chest X-ray, and echocardiogram. Median OS in the per protocol population was 109 days including one of five animals that died cancer-free at 16 months after documented resolution of relapsed disease. These results indicate that therapeutic administration of chemo-immunotherapy is both feasible and safe, substantiating the rationale for additional veterinary and human clinical studies.

Chemo-immunotherapy improves long-term survival in a preclinical model of MMR-D-related cancer

BACKGROUND

Mismatch Repair Deficiency (MMR-D)-related tumors are highly immunogenic and constitute ideal vaccination targets. In a proof-of-concept study delayed tumorigenesis and prolonged survival has been shown in a clinically-relevant mouse model for MMR-D-related diseases (=MLH1 knock out mice). To refine this approach, vaccination was combined with immune modulatory low-dose chemotherapy to polarize immune regulatory subtypes.

METHODS

Mice (prophylactic: 8-10 weeks; therapeutic: > 36 weeks) received a single injection of cyclophosphamide (CPX, 120 mg/kg bw, i.p.) or gemcitabine (GEM, 100 mg/kg bw, i.p.) prior to vaccination (lysate of a gastrointestinal tumor allograft, 10 mg/kg bw, n = 9 mice/group). The vaccine was given repetitively (10 mg/kg bw, s.c., 4 x / once a week, followed by monthly boosts) until tumor formation or progression. Tumor growth ([18F] FDG PET/CT imaging) and immune responses were monitored (flow cytometry, IFNγ ELISpot). The microenvironment was analyzed by immunofluorescence.

RESULTS

Prophylactic application of GEM + lysate delayed tumorigenesis compared to lysate monotherapy and CPX-pre-treatment (median time of onset: 53 vs. 47 vs. 48 weeks). 33% of mice even remained tumor-free until the experimental endpoint (= 65 weeks). This was accompanied by long-term effect on cytokine plasma levels; splenic myeloid derived suppressor cells (MDSC) as well as regulatory T cell numbers. Assessment of tumor microenvironment from GEM + lysate treated mice revealed low numbers of MDSCs, but enhanced T cell infiltration, in some cases co-expressing PD-L1. Therapeutic chemo-immunotherapy (GEM + lysate) had minor impact on overall survival (median time: 12 (GEM + lysate) vs. 11.5 (lysate) vs. 3 weeks (control)), but induced complete remission in one case. Dendritic and T cell infiltrates increased in both treatment groups. Reactive T cells specifically recognized MLH1-/- tumor cells in IFNγ ELISpot, but lacked response towards NK cell targets YAC-1.

CONCLUSIONS

Combined chemo-immunotherapy impairs tumor onset and growth likely attributable to modulation of immune responses. Depleting or 're-educating' immunosuppressive cell types, such as MDSC, may help moving a step closer to combat cancer.

Next Generation Immunotherapy for Pancreatic Cancer: DNA Vaccination is Seeking New Combo Partners

Pancreatic Ductal Adenocarcinoma (PDA) is an almost incurable radio- and chemo-resistant tumor, and its microenvironment is characterized by a strong desmoplastic reaction associated with a significant infiltration of T regulatory lymphocytes and myeloid-derived suppressor cells (Tregs, MDSC). Investigating immunological targets has identified a number of metabolic and cytoskeletal related molecules, which are typically recognized by circulating antibodies. Among these molecules we have investigated alpha-enolase (ENO1), a glycolytic enzyme that also acts a plasminogen receptor. ENO1 is also recognized by T cells in PDA patients, so we developed a DNA vaccine that targets ENO1. This efficiently induces many immunological processes (antibody formation and complement-dependent cytotoxicity (CDC)-mediated tumor killing, infiltration of effector T cells, reduction of infiltration of myeloid and Treg suppressor cells), which significantly increase the survival of genetically engineered mice that spontaneously develop pancreatic cancer. Although promising, the ENO1 DNA vaccine does not completely eradicate the tumor, which, after an initial growth inhibition, returns to proliferate again, especially when Tregs and MDSC ensue in the tumor mass. This led us to develop possible strategies for combinatorial treatments aimed to broaden and sustain the antitumor immune response elicited by DNA vaccination. Based on the data we have obtained in recent years, this review will discuss the biological bases of possible combinatorial treatments (chemotherapy, PI3K inhibitors, tumor-associated macrophages, ENO1 inhibitors) that could be effective in amplifying the response induced by the immune vaccination in PDA.

AIMp1 Potentiates TH1 Polarization and Is Critical for Effective Antitumor and Antiviral Immunity

Dendritic cells (DCs) must integrate a broad array of environmental cues to exact control over downstream immune responses including T_H polarization. The multienzyme aminoacyl-tRNA synthetase complex component AIMp1/p43 responds to cellular stress and exerts pro-inflammatory functions; however, a role for DC-expressed AIMp1 in T_H polarization has not previously been shown. Here, we demonstrate that the absence of AIMp1 in bone marrow-derived DC (BMDC) significantly impairs cytokine and costimulatory molecule expression, p38 MAPK signaling, and T_H1 polarization of cocultured T-cells while significantly dysregulating immune-related gene expression. These deficits resulted in significantly compromised BMDC vaccine-mediated protection against melanoma. AIMp1 within the host was also critical for innate and adaptive antiviral immunity against influenza virus infection in vivo. Cancer patients with AIMp1 expression levels in the highest tertiles exhibited a 70% survival advantage at 15-year postdiagnosis as determined by bioinformatics analysis of nearly 9,000 primary human tumor samples in The Cancer Genome Atlas database. These data establish the importance of AIMp1 for the effective governance of antitumor and antiviral immune responses.

Trial watch: DNA-based vaccines for oncological indications

DNA-based vaccination is a promising approach to cancer immunotherapy. DNA-based vaccines specific for tumor-associated antigens (TAAs) are indeed relatively simple to produce, cost-efficient and well tolerated. However, the clinical efficacy of DNA-based vaccines for cancer therapy is considerably limited by central and peripheral tolerance. During the past decade, considerable efforts have been devoted to the development and characterization of novel DNA-based vaccines that would circumvent this obstacle. In this setting, particular attention has been dedicated to the route of administration, expression of modified TAAs, co-expression of immunostimulatory molecules, and co-delivery of immune checkpoint blockers. Here, we review preclinical and clinical progress on DNA-based vaccines for cancer therapy.

Cancer vaccines and immunotherapeutic approaches in hepatobiliary and pancreatic cancers

Hepatobiliary and pancreatic cancers along with other gastrointestinal malignancies remain the leading cause of cancer-related deaths worldwide. Strategies developed in the recent years on immunotherapy and cancer vaccines in the setting of primary liver cancer as well as in pancreatic cancer are the scope of this review. Significance of orthotopic and autochthonous animal models which mimic and/or closely reflect human malignancies allowing for a prompt and trustworthy analysis of new therapeutics is underlined. Combinational approaches that on one hand, specifically target a defined cancer-driving pathway, and on the other hand, restore the functions of immune cells, which effector functions are often suppressed by a tumor milieu, are shown to have the strongest perspectives and future directions. Among combinational immunotherapeutic approaches a personalized- and individual cancer case-based therapy is of special importance.

Genetic Adjuvantation of a Cell-Based Therapeutic Vaccine for Amelioration of Chagasic Cardiomyopathy

Chagas disease, caused by infection with the protozoan parasite Trypanosoma cruzi, is a leading cause of heart disease ("chagasic cardiomyopathy") in Latin America, disproportionately affecting people in resource-poor areas. The efficacy of currently approved pharmaceutical treatments is limited mainly to acute infection, and there are no effective treatments for the chronic phase of the disease. Preclinical models of Chagas disease have demonstrated that antigen-specific CD8⁺ gamma interferon (IFN-γ)-positive T-cell responses are essential for reducing parasite burdens, increasing survival, and decreasing cardiac pathology in both the acute and chronic phases of Chagas disease. In the present study, we developed a genetically adjuvanted, dendritic cell-based immunotherapeutic for acute Chagas disease in an attempt to delay or prevent the cardiac complications that eventually result from chronic T. cruzi infection. Dendritic cells transduced with the adjuvant, an adenoviral vector encoding a dominant negative isoform of Src homology region 2 domain-containing tyrosine phosphatase 1 (SHP-1) along with the T. cruzi Tc24 antigen and trans-sialidase antigen 1 (TSA1), induced significant numbers of antigen-specific CD8⁺ IFN-γ-positive cells following injection into BALB/c mice. A vaccine platform transduced with the adenoviral vector and loaded in tandem with the recombinant protein reduced parasite burdens by 76% to >99% in comparison to a variety of different controls and significantly reduced cardiac pathology in a BALB/c mouse model of live Chagas disease. Although no statistical differences in overall survival rates among cohorts were observed, the data suggest that immunotherapeutic strategies for the treatment of acute Chagas disease are feasible and that this approach may warrant further study.