Tumor Cell Vaccine Research Articles

Invariant NKT cell-augmented GM-CSF-secreting tumor vaccine is effective in advanced prostate cancer model.

Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenicSV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenicTRAMP mice were then castrated at ~ 20weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation.

Bifunctional Fusion Membrane‐Based Hydrogel Enhances Antitumor Potency of Autologous Cancer Vaccines by Activating Dendritic Cells

AbstractAutologous tumor cell vaccine is an individualized tumor treatment strategy to elicit tumor‐specific immune responses. However, it is difficult to exert efficacy in “cold” tumors, which lack tumor‐infiltrating T cells and are not sensitive to immunotherapy. Here, a dendritic cells (DCs) activation hydrogel is constructed based on bifunctional fusion membrane nanoparticles (FM‐NPs) composed of autologous tumor cell membranes and Mycobacterium phlei membrane extracts. The FM‐NPs not only provide tumor antigens but also can activate DCs. Afterward, the FM‐NPs are loaded in an injectable alginate hydrogel together with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). GM‐CSF releases rapidly and recruits DCs to hydrogel, while FM‐NPs retain in hydrogel to continuously interconnected with DCs, enriching mature DCs loaded with tumor antigens. In the 4T1 mouse breast tumor model, this hydrogel promotes the maturation of DCs in tumor‐draining lymph nodes and induces sufficient effector memory T cells that migrate to the tumor microenvironment. This successfully converts the “cold” tumors to “hot”, thus exerting a significant antitumor effect synergized with the PD‐1 antibody. It is also verified the inhibitory effect of FM‐NPs using human gastric cancer organoids. Altogether, these findings demonstrate the application potential for the bifunctional fusion membrane‐based hydrogel as an autologous tumor vaccine by activating DCs.

IL-27 Improves Prophylactic Protection Provided by a Dead Tumor Cell Vaccine in a Mouse Melanoma Model

The protocol used to induce cell death for generating vaccines from whole tumor cells is a critical consideration that impacts vaccine efficacy. Here we compared how different protocols used to induce cell death impacted protection provided by a prophylactic whole tumor cell vaccine in a mouse melanoma model. We found that melanoma cells exposed to γ-irradiation or lysis combined with UV-irradiation (LyUV) provided better protection against tumor challenge than lysis only or cells exposed to UV-irradiation. Furthermore, we found that the immunoregulatory cytokine, IL-27 enhanced protection against tumor growth in a dose-dependent manner when combined with either LyUV or γ-irradiated whole tumor cell vaccine preparations. Taken together, this data supports the use of LyUV as a potential protocol for developing whole tumor cell prophylactic cancer vaccines. We also showed that IL-27 can be used at low doses as a potent adjuvant in combination with LyUV or γ-irradiation treated cancer cells to improve the protection provided by a prophylactic cancer vaccine in a mouse melanoma model.

Anti-Gr-1 Antibody Provides Short-Term Depletion of MDSC in Lymphodepleted Mice with Active-Specific Melanoma Therapy.

Lymphodepletion, reconstitution and active-specific tumor cell vaccination (LRAST) enhances the induction of tumor-specific T cells in a murine melanoma model. Myeloid-derived suppressor cells (MDSC) may counteract the induction of tumor-reactive T cells and their therapeutic efficacy. Thus, the aim of the study was to evaluate a possible benefit of MDSC depletion using anti-Gr-1 antibodies (Ab) in combination with LRAST. Female C57BL/6 mice with 3 days established subcutaneous (s.c.) D5 melanoma were lymphodepleted with cyclophosphamide and reconstituted with naive splenocytes. Vaccination was performed with irradiated syngeneic mGM-CSF-secreting D5G6 melanoma cells. MDSC depletion was performed using anti-Gr-1 Ab (clone RB6-8C5). Induction of tumor-specific T cells derived from tumor vaccine draining lymph nodes (TVDLN) was evaluated by the amount of tumor-specific interferon (IFN)-γ release. LRAST combined with anti-Gr-1 mAb administration enhanced the induction of tumor-specific T cells in TVDLN capable of releasing IFN-γ in a tumor-specific manner. Additional anti-Gr-1 mAb administration in LRAST-treated mice delayed growth of D5 melanomas by two weeks. Furthermore, we elucidate the impact of anti-Gr-1-depleting antibodies on the memory T cell compartment. Our data indicate that standard of care treatment regimens against cancer can be improved by implementing agents, e.g., depleting antibodies, which target and eliminate MDSC.

CD24 + MDSC-DCs Induced by CCL5-Deficiency Showed Improved Antitumor Activity as Tumor Vaccines.

Background Dendritic cell (DC) tumor vaccine has been extensively utilized in preclinical and clinical studies; however, this technique has encountered many difficulties, particularly in late-stage tumor patients. For those, ex vivo-induced DCs are actuallymyeloid-derived suppressive cells-derived DCs (MDSC-DCs). MDSCs with immunosuppressive activity, but not monocytes, became the major DC precursor. Thus, how to enhance antitumor activity of MDSC-DCs is urgent need to address. Methods We utilized 4T1 and MC38 tumor-bearing both wildtype and CC chemokine ligand 5 −/− (CCL5 −/− ) mice as animal models. MDSC-DCs were induced from splenocytes of these mice by granulocyte macrophage–colony stimulating factor/interleukin-4 with or without all-trans-retinoic acid (ATRA) in vitro for 7 days, then incubated with tumor-cell-lysis to treat mouse models for total three doses. For human MDSC-DCs, peripheral bloods from colorectal cancer patients were induced in vitro as murine cells with or without T- lymphocytes depletion to get rid of CCL5. Results Flow cytometry analysis showed that MDSCs from CCL5 −/− mice could be induced into a new type of CD24 + MDSC-DCs in the presence of ATRA, which had more antitumor activity than control. Antibody blocking and adoptive transfer experiments demonstrated that downregulation of regulatory T cells (Tregs) mediated the inhibition of CD24 + MDSC-DCs on tumor growth. Mechanically, CD24 + MDSC-DCs inhibited Tregs' polarization by secreting cytokine or coactivators' expression. What's important, decreasing CCL5 protein levels by T- lymphocytes depletion during both murine and human MDSC-DCs in vitro induction could also acquire CD24 + MDSC-DCs. Conclusion Knockdown of CCL5 protein during MDSC-DCs culture might provide a promising method to acquire DC-based tumor vaccines with high antitumor activity.

Neoadjuvant and adjuvant antitumor vaccination alone or combination with PD1 blockade and CD137 agonism in patients with resectable pancreatic adenocarcinoma.

558 Background: Utilizing a vaccine that induces and activates host effector T cells and co-administering it with immune modulating agents that enhance anti-tumor T cell activity is a potential strategy for overcoming pancreatic adenocarcinoma’s (PDA) resistance to immunotherapy. Our prior clinical trial demonstrated a GM-CSF-secreting, allogeneic tumor cell vaccine (GVAX) increases infiltrating CD8+ T cells in PDA. Follow up preclinical work demonstrated therapeutic synergy between GVAX and PD-1inhibition (PD1) with efficacy further enhanced by CD137 agonism (CD137). Methods: This was a 3-arm trial of neoadjuvant & adjuvant GVAX-based therapy in resectable (r) PDA patients (pts). Adults with clinically resectable, untreated PDA were enrolled in 1 of 3 study treatments: Arm A (GVAX alone), Arm B (GVAX + PD1 [Nivolumab]), or arm C (GVAX + PD1 + CD137 [Urelumab]). Treatment was given as follows: Day 1 - Cyclophosphamide 200mg/m2 IV (All Arms), Nivolumab 480mg IV (Arms B, C), Urelumab 8mg IV (Arm C); Day 2 – GVAX ID (All Arms). Pts were treated at 3 timepoints: 1) once 2 weeks prior to surgery; 2) once post-surgical recovery prior to standard of care adjuvant chemotherapy (SOC); 3) every month (up to 4 mo) following completion of SOC (if disease-free). SOC regimes included (m)FOLFIRINOX, Gem +/- Cap/NAB-Paclitaxel. The study was powered for a primary biologic endpoint: treatment-related change in intratumoral CD8+CD137+ T cells. Clinical endpoints included disease-free survival (DFS: time from surgery to recurrence), overall survival (OS: time from surgery to death), and safety. Results: 38 pts (N = 15 [Arm A], N = 13 [Arm B], N = 10 [Arm C]) were eligible for efficacy analysis (had R0/R1 resection) and 45 pts (N = 17 [A], N = 17 [B], N = 11 [C]) were eligible for safety analysis (had ≥1 dose of study treatment). Demographics, surgical pathology features, and SOC durations were similar in all Arms. At median follow up of 23 mo [A], 26 mo [B], and 22 mo [C], median DFS (95% CI) was 14.82 mo (6.0, NA), 16.23 mo (7.49, NA) and not reached (16.33, NA) for Arms A, B, C, respectively. There was no DFS benefit to adding PD1 compared to GVAX alone (HR 0.98 [95% CI 0.42, 2.27], p = 0.96). Combination CD137 + PD1 + GVAX was associated with marginally significant improved DFS compared to GVAX alone (HR 0.38 [95%CI 0.12, 1.19], p = 0.097) and GVAX + PD1 (HR 0.38 [95%CI 0.12, 1.21], p = 0.103). Median OS (95% CI) was 25.0 mo (18.8, NA), 26.4 mo (20.3, NA), and not yet reached for Arms A, B, C, respectively. There were no serious adverse events. In Arm C, 1 pt had grade 3 rash that delayed treatment and there was 1 instance of grade 2 AST/ALT elevation. The biologic endpoint will be reported at the meeting. Conclusions: Despite a small sample size, combining GVAX with dual immune-targeting of PD-1 blockade and CD137 agonism was safe and may enhance DFS in rPDA pts treated in the perioperative and post-adjuvant settings. Clinical trial information: NCT02451982.

An Evidence-based Medical Research on the Comparative Quantification of TGF? and Telomerase Experimentations, with their Molecular Pharmacological Analyses as Targets of Oncoimmunotherapeutic Vaccines

The basic oncotherapeutic vaccines used are cell based vaccines including whole cell vaccines, genetically modified tumour cell vaccines and dendritic cell vaccines, anti-idiotype antibody based vaccines, protein or peptide based vaccines, heat shock proteinbased vaccines, viral, bacterial or yeast vectors based vaccines, mRNA or DNA nucleic acid based vaccines, vaccines based on tumour associated antigens like overexpressed proteins, differentiation antigens, cancer-testis antigens and oncofoetal antigens, and tumour specific antigens including oncogenic viral antigens, antigen presenting cells or molecular neoantigens based vaccines with specific CD8+ T cells and, CD4+ T cells, and nanoparticles vectors based vaccines. The objective of this evidence-based medical research was the comparative quantification of TGF? and telomerase experimentations, with their molecular pharmacological analyses as targets of oncoimmunotherapeutic vaccines. A molecular pharmacological multi-variate, qualitative, analytical study of the retrieved literature derived through a thorough literature review from various available literature databases, was performed, to record, review, thoroughly analyse and delineate the molecular pharmacological basis of oncoimmunotherapeutic vaccines from a wide-ranged study literature containing molecular pharmacological researches, reviews, case presentations and varied databases about the pharmacooncoimmunotherapeutic rationale of the clinical use of vaccines in the treatment of cancer patients, with a specific emphasis on telomerase and TGF?, as molecular pharmacological targets of oncoimmunotherapeutic vaccines. After that, a multivariate evidence-based medical research study of comparative quantification and analysis of the global heterogenous multidisciplinary experimentations and study literature on telomerase and TGF?, as molecular pharmacological targets of pharmaco-oncoimmuno-therapeutic vaccines, affecting global malignant and borderline malign

Combined Stereotactic Ablative Radiotherapy and Fibroblast Activation Protein Based Whole Cell Tumor Vaccine Synergize to Suppress Tumor Growth and Metastasis

Cancer-associated fibroblasts (CAFs), which occupy a major portion of the TME, play an important role in tumor growth, immunosuppression, treatment resistance. Our studies found that fibroblast activation protein α (FAPα) based whole cell tumor vaccine (WCTV) can induce a cross-immune response to produce specific neutralizing antibodies and CTL effects to kill tumor cells and CAFs. However, the therapeutic efficacy of vaccination is limited. Recent studies have revealed that stereotactic ablation radiotherapy (SABR) also elicit systemic antitumor immunity, which makes it an ideal partner for immunotherapy. The goal of this study was to examine synergistic effect of SABR and FAP-based WCTV.We produced FAPα-based WCTV by infecting tumor cells with lentiviral vector pCDH encoding FAPα, and then inactivating them with radiation (100Gy) for immunotherapy in vivo. To investigate the optimal protocol, we compared different SABR schemes and sequence of the combination of irradiation and FAPα- based WCTV in mouse LLC Lewis lung cancer model. Subsequently, we tested whether the combination protocol would result in enhanced anti-tumor activity and antifibrotic effect in mouse 4T1 breast cancer and CT26 colon cancer models. Furthermore, we analyzed the impact of treatment on cellular immunophenotypic characterization in TME via immunohistochemical staining and flow cytometry.We demonstrated that the therapeutic effect of SABR combined with FAPα-based WCTV is better than radiotherapy or vaccination alone. We identified the optimal dose scheme of SABR synergistically with FAPα- based WCTV is a single dose of 8Gy × 3 times, and the best treatment sequence is radiotherapy within one week after the first vaccination (three times in total). The optimal combination protocol also resulted in enhanced anti-tumor activity and antifibrotic effect against 4T1 breast cancer and CT26 colon cancer, and inhibited lung metastasis in breast cancer. No adverse effects were found based on gross measures of health. Importantly, collagen type I and FAPα expression in tumor tissue was significantly lower in SABR+ Vaccine treated mice than in control mice. SABR combined with FAPα-based WCTV reduced microvascular and lymphatic invasion, allowed polarization of tumor-associated macrophages to the M1-like phenotype. The relative percentage of M2 macrophages, MDSCs, and Tregs significantly decreased in the peripheral blood and lymph nodes. By contrast, CD8+ T lymphocytes especially activated cells increased.Our findings indicate that combined FAPα-based WCTV and SABR synergize to suppress tumor growth and metastasis via activating the systemic anti-tumor immune response, attenuating CAFs-mediated immunosuppression, interstitial fibrosis and treatment resistance. This novel combination of radio-immunotherapy may add a new perspective to cancer treatments.

Hydrogel/nanoadjuvant-mediated combined cell vaccines for cancer immunotherapy

Combined cell vaccines of tumor whole cells and dendritic cells (DCs) provide an effective individualized immunotherapy for malignant tumors. We propose an innovative strategy termed “biomaterial-mediated combined cell vaccines for immunotherapy,” which combines tumor cell and DC vaccines with a cyclodextrin-polyethylene glycol hydrogel and a cytosine-phosphate-guanine (CpG) nanoadjuvant. The nanoadjuvant promotes antigen presentation and amplifies immune-eliciting potency by co-delivery of antigens and adjuvants. The hydrogel scaffold provides a better growth microenvironment for injected exogenous DCs and recruits endogenous DCs to maintain their viability for synergistic effect. The results indicated that, relative to live tumor cells, the immunogenically dying tumor cells activated DC maturation effectively with the auxiliary effect of immune adjuvant CpG nanoparticles. The increased T cell percentage, proliferation ability, cytokine secretion, and cytotoxic effect revealed the enhanced immunogenicity of the combined cell vaccines. The combined hydrogel/nanoadjuvant system showed the best efficiency in inhibiting tumor growth. Moreover, vaccination with a single dose of hydrogel-based combined vaccines significantly delayed the development of tumors. The biomaterial-mediated combined cell vaccines remarkably increased the infiltration of effector T cells, alleviated the intratumoral immunosuppressive microenvironment, and maximized the immune effect of the vaccines, thus improving cancer immunotherapy. Statement of significanceCell-based vaccines, including tumor whole-cell vaccine or DC vaccine, have attracted wide attention as an effective method for cancer immunotherapy. However, it is difficult to gain satisfactory outcomes in clinical trials because of the low immunogenicity of tumor whole cell vaccine and the short-term survival of transferred DC vaccine. Therefore, improving the ability of cell-based vaccines to induce a strong and durable immune response is the primary objective for vaccine development. Biomaterial-mediated combined cell vaccines is an innovative strategy for cancer immunotherapy. The combined hydrogel/ nanoadjuvant system comprises immunogenically dying tumor cells, DCs, and nanoadjuvants. Nanoadjuvant-loaded immunogenically dying tumor cells can induce efficient immune response as the tumor cell vaccine. The hydrogel-based combined tumor cell/DC vaccine could be used for individualized immunotherapy.

Optimization of Whole Tumor Cell Vaccines by Interaction with Phagocytic Receptors.

The principal event in the function of whole-cell cancer vaccines is the ingestion of vaccine-delivered tumor antigen-containing material, which is performed by the patient’s antigen-presenting cells (APCs) through the employment of their phagocytic receptors. The goal of the present study was to identify the phagocytic receptors critical for the therapeutic efficacy of whole-cell cancer vaccines. The model of photodynamic therapy (PDT)-generated vaccines based on mouse SCCVII tumors was utilized, with in vitro expanded SCCVII cells treated by PDT serving as the vaccine material used for treating mice bearing established SCCVII tumors. The therapeutic impact, monitored as delayed progression of vaccinated tumors, was almost completely eliminated when antibodies specifically blocking the activity of LOX-1 scavenger receptor were administered to mice 30 min before vaccination. Similar, but much less pronounced, impacts were found with antibodies neutralizing the activity of CR3/CR4 receptors recognizing complement-opsonized vaccine cells, and with those blocking activating Fcγ receptors that recognized IgG antibody-based opsonins. A strikingly contrary action, a greatly enhanced tumor control by the vaccine, was found by blocking immune inhibitory receptor, FcγRIIB. The reported findings establish, therefore, an attractive strategy that can be effectively exploited for potent therapeutic enhancement of PDT-generated (and probably other) whole-cell tumor vaccines.

Targeted Immunotherapies in Gastrointestinal Cancer: From Molecular Mechanisms to Implications.

Gastrointestinal cancer is a leading cause of cancer-related mortality and remains a major challenge for cancer treatment. Despite the combined administration of modern surgical techniques and chemoradiotherapy (CRT), the overall 5-year survival rate of gastrointestinal cancer patients in advanced stage disease is less than 15%, due to rapid disease progression, metastasis, and CRT resistance. A better understanding of the mechanisms underlying cancer progression and optimized treatment strategies for gastrointestinal cancer are urgently needed. With increasing evidence highlighting the protective role of immune responses in cancer initiation and progression, immunotherapy has become a hot research topic in the integrative management of gastrointestinal cancer. Here, an overview of the molecular understanding of colorectal cancer, esophageal cancer and gastric cancer is provided. Subsequently, recently developed immunotherapy strategies, including immune checkpoint inhibitors, chimeric antigen receptor T cell therapies, tumor vaccines and therapies targeting other immune cells, have been described. Finally, the underlying mechanisms, fundamental research and clinical trials of each agent are discussed. Overall, this review summarizes recent advances and future directions for immunotherapy for patients with gastrointestinal malignancies.

A Bayesian network meta-analysis of comparison of cancer therapeutic vaccines for melanoma.

Several approaches to active immunotherapy for melanoma, including peptide‐based vaccines (PVs), autologous tumour cell vaccines (TCVs), allogeneic TCVs and autologous dendritic cell vaccines (DCVs), have been investigated in clinical trials. However, comprehensive evidence comparing these interventions remains unavailable. The objective of this study was to expand previous work to compare and rank the immunotherapeutic strategies for melanoma in terms of overall survival and toxic effects with a Bayesian network meta‐analysis. Methodologically, we performed a network meta‐analysis of head‐to‐head randomized controlled trials comparing and ranking cancer vaccine approaches for patients with melanoma. PubMed, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov were searched up to 31 July 2020. We estimated summary hazard ratios for death and risk ratios for toxicity. The effects of the underlying prognostic variable on survival benefits were examined by meta‐regression. We performed subgroup analysis for the outcomes based on metastatic categories. Overall, we identified 4776 citations, of which 15 head‐to‐head randomized controlled trials (3162 participants) were included in the analysis. In terms of efficacy, allogeneic tumour cell vaccines plus immunotherapy adjuvants, peptide‐based vaccines plus immunotherapy adjuvants and standard therapy were more effective than peptide vaccines. The proportion of women was inversely associated with mortality risk. For safety, all treatments were inferior to allogeneic tumour cell vaccines except for allogeneic tumour cell vaccines plus chemotherapy. Peptide vaccines plus immunotherapy adjuvants led to an increased risk of adverse events compared to allogeneic tumour cell vaccines plus immunotherapy adjuvants. These results suggest that allogeneic TCV and autologous DCV are better than standard therapy. PV plus immune modulators are the most effective strategy among all comparable strategies but is associated with increased toxicity. Any combination regimens for cancer therapeutic vaccines need to be balanced between risk and benefit profiles.

Whole tumor cell vaccines engineered to secrete GM‐CSF (GVAX)

AbstractGeneration of immunity against cancer through vaccination has long been an elusive goal for tumor immunologists. Putative candidates for vaccination targets include oncofetal antigens, viral antigens, neoantigens, and differentiation antigens. The first attempts at cancer vaccination used injections of whole autologous tumor cells. However, these unmodified tumor cells did not engender a robust immune response. Subsequent efforts were focused at enhancing the immunogenicity of whole autologous tumor cell vaccines through genetic modification, often through virally mediated transduction of genes encoding immunostimulatory molecules. Of many immunostimulatory cytokines evaluated in the context of gene‐modified tumor cell vaccines, granulocyte–macrophage colony‐stimulating factor (GM‐CSF) emerged as the most potent in generating protective antitumor immunity. Vaccination using irradiated, GM‐CSF producing tumor cells (GVAX) consistently induced antitumor immunity across several experimental tumor models. The term GVAX can connote GM‐CSF secreting cell vaccines prepared with different vectors as well as vector targets including autologous tumor cells, allogeneic tumor cell lines, and bystander third party tumor cells lines. GVAX has been evaluated against solid tumors, hematologic malignancies, and in the context of hematopoietic stem cell transplantation. GVAX has been extensively studied in clinical trials, both alone and in conjunction with lymphodepleting chemotherapy, immune checkpoint inhibitors, and other vaccines.

Maintenance vigil immunotherapy in newly diagnosed advanced ovarian cancer: Efficacy assessment of homologous recombination proficient (HRP) patients in the phase IIb VITAL trial.

5502 Background: In the VITAL (NCT02346747) trial, maintenance therapy with Vigil, an autologous tumor cell vaccine transfected with a DNA plasmid encoding GMCSF and bi-shRNA-furin for TGFβ expression control, following frontline platinum-based chemotherapy led to a recurrence-free survival (RFS) benefit in patients with advanced high-grade ovarian cancer (HR=0.69, 90% CI 0.44–1.07, p=0.078) and significantly in BRCA-wt patients (HR=0.51, 90% CI 0.30-0.88, p=0.020) ( Rocconi et al. Lancet Oncol. 2020). Here we report post-hoc HR deficiency (HRD) subgroup analysis and identification of an additional molecular subgroup sensitive to Vigil therapy involving STRING analysis. Methods: This double-blind, placebo-controlled, Phase 2b study randomized 92 patients with newly diagnosed stage III/IV ovarian cancer with a complete clinical response (CR) to frontline surgery and chemotherapy. Patients received 1 x 10e7 cells/ml of Vigil or placebo intradermally once a month for up to 12 doses or disease progression. RFS was the primary endpoint assessed by blinded independent central review. HRD status was determined according to the Myriad Genetics myChoice CDx assay (HRD score < 42 for proficient). Using tumor annotated DNA polymorphism data, a protein-protein interaction network was constructed using the STRING database. Properties of this network including topological distance and the identification of hub genes were used to predict a target molecular population sensitive to Vigil. Results: In the per-protocol population (PP, n=91), 62 BRCA-wt patients were tested for HRD status. Forty-five patients were HR proficient (HRP) and 17 patients were HR deficient (HRD). No HRP patients in the Vigil group reported treatment related Grade 3 or higher adverse events. From the time of study randomization median RFS was improved with Vigil (n=25) in HRP patients compared to placebo (n=20) (Table 1). Similarly, overall survival (OS) benefit was observed in the Vigil group compared to placebo (Table 1). Improved RFS was demonstrated for a subset of patients with STRING predicted molecular profile. Conclusions: Vigil immunotherapy as frontline maintenance in Stage III/IV ovarian cancer is well tolerated and showed clinical benefit in both BRCA-wt and HRP molecular profile patients. Results suggest a unique molecular network that enhances sensitivity to Vigil therapy. Clinical trial information: NCT02346747. [Table: see text]

Correction: A Virus-infected, Reprogrammed Somatic Cell-derived Tumor Cell (VIReST) Vaccination Regime can Prevent Initiation and Progression of Pancreatic Cancer.

Purpose: Pancreatic cancer remains one of the most lethal cancers, and late detection renders most tumors refractory to conventional therapies. Development of cancer prophylaxis may be the most realistic option for improving mortality associated with this disease. Here, we develop a novel individualized prophylactic and therapeutic vaccination regimen using induced pluripotent stem cells (iPSC), gene editing, and tumor-targeted replicating oncolytic viruses. Experimental Design: We created a Virus-Infected, Reprogrammed Somatic cell-derived Tumor cell (VIReST) regime. iPSCs from healthy cells were induced to pancreatic tumor cells using in situ gene editing via stable provision of KRasG12D and p53R172H tumor driver mutations. These cells were preinfected with oncolytic Adenovirus (AdV) as prime or Vaccinia virus (VV) as boost, to improve vaccine immunogenicity, prior to delivery of vaccines in a sequential regime to young KPC transgenic mice, genetically programmed to develop pancreatic cancer, to prevent and delay disease development. Results: Tumor cells preinfected with oncolytic AdV as prime or VV as boost were the best regime to induce tumor-specific immunity. iPSC-derived tumor cells were highly related in antigen repertoire to pancreatic cancer cells of KPC transgenic mice, suggesting that an individual9s stem cells can provide an antigenically matched whole tumor cell vaccine. The VIReST vaccination primed tumor-specific T-cell responses, resulting in delayed disease emergence and progression and significantly prolonged survival of KPC transgenic mice. Importantly, this regime was well-tolerated and nontoxic. Conclusions: These results provide both proof of concept and a robust technology platform for the development of personalized prophylactic cancer vaccines to prevent pancreatic malignancies in at-risk individuals.

MicroRNA-365 promotes apoptosis in human melanoma cell A375 treated with hydatid cyst fluid of Echinococcus granulosus sensu stricto

Hydatid cyst fluid (HCF)-based therapeutics has experimentally targeted approaches for treating human cancer cell lines. MicroRNA-365 (miR-365) has been reported to be an important tumor suppressor miRNA in cancers. However, it remains unknown, how miR-365 plays a pivotal role in inducing apoptosis in HCF-treated cancer cells in vitro. The fertile/infertile HCF was aspirated from liver of infected sheep and in terms of molecular taxonomy was identified as G1 genotype of Echinococcus granulosus sensu stricto. A375 human melanoma cancer cells were cultured into two groups: fertile and infertile HCF-treated A375 cells. To assess the cytotoxicity of various concentrations of HCF on melanoma cells, cell viability was determined by using MTT assay. The IC50 value of HCF on A375 cells was determined 85 μg/mL. Caspase-3 enzymatic activity was evaluated by fluorometric assay in the HCF-treated melanoma cells. In addition, the mRNA expression of Bax, Bcl-2, Caspase-9 and miR-365 were determined by qRT-PCR. Findings of MTT assay showed that concentrations 85 μg/mL to 100 μg/mL of fertile HCF have the highest mortality (50%–52%) on A375 cells during 24 h. The fold change of Bax/Bcl-2 ratio, Caspase-9, miR-365 and Caspase-3 activity was higher in the fertile HCF-treated melanoma cells compared to infertile fluid treated A375 cells and human normal epithelial cell (as control cell). In conclusion, we over-expressed the miR-365 in melanoma A375 cells, via treatment of fertile HCF. Our findings suggested that inducing high expression of miR-365 might be a negative regulator of melanoma growth through activation of pro-apoptotic Bax, Caspase-9 and Caspase-3 that are essential to intrinsic apoptotic pathway. These findings provide new insights into the use of Echinococcus HCF-derived metabolites in the design of drug therapies and in vivo tumor cell vaccine to combat melanoma progression.

Hydrogel/Nanoadjuvant-Mediated Combined Cell Vaccines for Cancer Immunotherapy

Cancer immunotherapy aims to effectively eliminate the residual tumor cells and prevent tumor recurrence and metastasis. The combined cell vaccines of tumor whole cell and dendritic cells (DC) provide an effective individualized immunotherapy for malignant tumors. It is a key issue how to improve the immunogenicity of tumor whole cell vaccine and maintain DC activity for antigen presentation in vivo. We proposed an innovative strategy called “biomaterial-mediated combined cell vaccines for immunotherapy”, which combined tumor cell vaccine and DC vaccine by cyclodextrin-polyethylene glycol hydrogel and CpG nanoadjuvant. The nanoadjuvant promoted antigen presentation level and amplified immune eliciting potency by co-delivery of antigen and adjuvant. The hydrogel scaffold provided a better growth microenvironment for injected exogenous DC and recruited endogenous DC to maintain their viability and play their synergistic action. Based on effective antigen presentation from the combination of tumor antigen, adjuvant and DC, the combined cell vaccines induced strong CTL killing effect to continuously stimulate the body's specific anti-tumor immunity. The combined hydrogel/ nanoadjuvant system merged immunogenically dying tumor cells, DC and adjuvants, which remarkably increased the infiltration of effector T cells, alleviated the intratumoral immunosuppressive microenvironment and maximized the immune effect of the vaccines for improving the cancer immunotherapy.

Combinations of Radiotherapy with Vaccination and Immune Checkpoint Inhibition Differently Affect Primary and Abscopal Tumor Growth and the Tumor Microenvironment.

Simple SummaryRadiotherapy (RT) with higher single doses is capable of creating a beneficial immunological tumor microenvironment for additional immune therapies to trigger systemic anti-tumor immune responses. Here, we aimed to boost RT-induced immune responses with inactivated whole tumor cell vaccines generated with high hydrostatic pressure (HHP) and to break immunosuppression by inhibition of suppressive immune checkpoint molecules, such as PD-1. Our results highlight that HHP vaccines act systemically to retard tumor growth, but only of previously irradiated tumors. In contrast, abscopal anti-tumor immune responses, namely those to non-irradiated tumors, are triggered by a combination of RT of not too many fractions plus anti-PD-1, being characterized by the induction of distinct immune alterations in the primary and abscopal tumor, respectively. This emphasizes that future multimodal radioimmunotherapy approaches need to be carefully optimized regarding RT fractionation and the interaction of different immunotherapies with each other.Radiotherapy (RT) is known to have immune-modulatory properties. We hypothesized that RT and inactivated whole tumor cell vaccines generated with high hydrostatic pressure (HHP) synergize to retard the tumor growth which can be additionally improved with anti-PD-1 treatment. In abscopal tumor models, we injected mice with B16-F10 melanoma or TS/A mammary tumors. To evaluate the efficiency of RT in combination with HHP vaccines, we locally irradiated only one tumor with 2 × 8 Gy or 3 × 8 Gy. HHP vaccines further retarded the growth of locally irradiated (2 × 8 Gy) tumors. However, HHP vaccination combined with RT failed to induce abscopal anti-tumor immune responses, namely those to non-irradiated tumors, and even partly abrogated those which were induced with RT plus anti-PD-1. In the latter group, the abscopal effects were accompanied by an elevated infiltration of CD8+ T cells, monocytes/macrophages, and dendritic cells. 3 × 8 Gy failed to induce abscopal effects in association with increased expression of immunosuppressive checkpoint molecules compared to 2 × 8 Gy. We conclude that HHP vaccines induce anti-tumor effects, but only if the tumor microenvironment was previously modulated by hypofractionated RT with not too many fractions, but failed to improve RT plus anti-PD-induced abscopal responses that are characterized by distinct immune alterations.

Dormant Tumor Cell Vaccination: A Mathematical Model of Immunological Dormancy in Triple-Negative Breast Cancer.

Simple SummaryTriple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, particularly affecting young women. Chemotherapy is the main choice for the treatment of these patients. It has been shown that some chemotherapies induce immunogenic cell death and elicit an adaptive cytotoxic T cell immune response through the activation of the type I interferon pathway. We made an evolutionary mathematical model based on the recently reported in vivo induction of immunological tumor dormancy of a murine TNBC cell line upon in vitro treatment with chemotherapy. Our model replicates the previously obtained experimental results and predicts a prophylactic and therapeutic vaccination effect by injecting dormant cells with active type I interferon signaling, before or after challenge with the aggressive parental tumor cells, respectively. These results show the potential of a dormant tumor cell-based therapy inducing an adaptive immune response, suppressing tumor growth.Triple-negative breast cancer (TNBC) is a molecular subtype of breast malignancy with a poor clinical prognosis. There is growing evidence that some chemotherapeutic agents induce an adaptive anti-tumor immune response. This reaction has been proposed to maintain the equilibrium phase of the immunoediting process and to control tumor growth by immunological cancer dormancy. We recently reported a model of immunological breast cancer dormancy based on the murine 4T1 TNBC model. Treatment of 4T1 cells in vitro with high-dose chemotherapy activated the type I interferon (type I IFN) signaling pathway, causing a switch from immunosuppressive to cytotoxic T lymphocyte-dependent immune response in vivo, resulting in sustained dormancy. Here, we developed a deterministic mathematical model based on the assumption that two cell subpopulations exist within the treated tumor: one population with high type I IFN signaling and immunogenicity and lower growth rate; the other population with low type I IFN signaling and immunogenicity and higher growth rate. The model reproduced cancer dormancy, elimination, and immune-escape in agreement with our previously reported experimental data. It predicted that the injection of dormant tumor cells with active type I IFN signaling results in complete growth control of the aggressive parental cancer cells injected at a later time point, but also of an already established aggressive tumor. Taken together, our results indicate that a dormant cell population can suppress the growth of an aggressive counterpart by eliciting a cytotoxic T lymphocyte-dependent immune response.

Adenosine triphosphate, polymyxin B and B16 cell-derived immunization induce anticancer response.

Aim: Whole dead tumor cells can be used as antigen source and the induction of protective immune response could be enhanced by damage-associated molecular patterns. Materials & methods: We generated whole dead tumor cells called B16-immunogenic cell bodies (ICBs) from B16 melanoma cells by nutrient starvation and evaluated the in vivo antitumor effect of B16-ICBs plus ATP and polymyxin B (PMB). Results: The subcutaneous immunization with B16-ICBs+PMB+ATP a 50% of tumor-free animals and induced a significant delay in tumor growth in a prophylactic approach. These results correlated with maturation of bone marrow-derived dendritic cells and activation of T CD8+ lymphocytes in vitro. Conclusion: Altogether, ICB+ATP+PMB is efficient in inducing the antitumor efficacy of the whole dead tumor cells vaccine.