Cancer-specific Immune Response Research Articles

Targeted siRNA Delivery by Bioinspired Cancer Cell Membrane-Coated Nanoparticles with Enhanced Anti-Cancer Immunity.

Cell-membrane nanocarriers are usually constructed by modifying the nanoparticle surface with cell membrane extracts, which has a direct benefit in endowing targeting capacity to nanocarriers based on their original cell types. However, delivering nucleic acid cargos by cell membrane-based nanoparticles is difficult owing to the strong negative charge of the cell membrane fraction. In this study, we developed a cancer cell membrane-based drug delivery system, the cMDS, for efficient siRNA delivery. Meanwhile, the cancer-specific immune response stimulated by the gene vector itself could offer synergistic anti-cancer ability. The cMDS was prepared by ultrasound, and its transfection efficiency and anti-cancer ability were examined using cultures of CT26 cells. MTT and red blood cell hemolysis tests were performed to assess the safety of cMDS, while its targeted gene delivery and strong immune stimulation were investigated in a subcutaneous tumor model. Moreover, the detailed anti-cancer immune stimulation mechanisms of cMDS are uncovered by protein chip analysis. The cMDS was spherical core-shell structure. It showed high transfection efficiency and anti-cancer ability in vitro. In animal experiments, intravenously administered cMDS/siStat3 complex efficiently suppress the growth of colon cancer. Moreover, the result of protein chip analysis suggested that cMDS affect the migration and chemotaxis of immune cells. The cMDS shows obvious tumor tissue-specific accumulation properties and strong immune stimulation ability. It is an advanced targeted gene delivery system with potent immunotherapeutic properties.

An injectable signal-amplifying device elicits a specific immune response against malignant glioblastoma

Despite exciting achievements with some malignancies, immunotherapy for hypoimmunogenic cancers, especially glioblastoma (GBM), remains a formidable clinical challenge. Poor immunogenicity and deficient immune infiltrates are two major limitations to an effective cancer-specific immune response. Herein, we propose that an injectable signal-amplifying nanocomposite/hydrogel system consisting of granulocyte-macrophage colony-stimulating factor and imiquimod-loaded antigen-capturing nanoparticles can simultaneously amplify the chemotactic signal of antigen-presenting cells and the “danger” signal of GBM. We demonstrated the feasibility of this strategy in two scenarios of GBM. In the first scenario, we showed that this simultaneous amplification system, in conjunction with local chemotherapy, enhanced both the immunogenicity and immune infiltrates in a recurrent GBM model; thus, ultimately making a cold GBM hot and suppressing postoperative relapse. Encouraged by excellent efficacy, we further exploited this signal-amplifying system to improve the efficiency of vaccine lysate in the treatment of refractory multiple GBM, a disease with limited clinical treatment options. In general, this biomaterial-based immune signal amplification system represents a unique approach to restore GBM-specific immunity and may provide a beneficial preliminary treatment for other clinically refractory malignancies.

Development of a Cancer Nanovaccine to Induce Antigen-specific Immune Responses Based on Large-Sized Porous Silica Nanoparticles.

Cancer vaccine is one of the immunotherapeutic strategies aiming to effectively deliver cancer antigens to professional antigen-presenting cells such as dendritic cells (DCs), macrophages, and B cells to elicit a cancer-specific immune response. Despite the advantages of the cancer vaccine that can be applied to various cancer types, the clinical approach is limited due to the non-specific or adverse immune responses, stability, and safety issues. In this study, we report an injectable nanovaccine platform based on large-sized (∼350 nm) porous silica nanoparticles (PSNs). We found that large-sized PSNs, called PS3, facilitated the formation of an antigen supply depot at the site of injection so that a single injection of PSN-based nanovaccine elicited sufficient tumor-specific cell-mediated and humoral immune response. As a result, antigen-loaded PS3 induced successful tumor regression in prophylactic and therapeutic vaccination.

Randomized phase II trial in prostate cancer with hormone-sensitive OligometaSTatic relapse: Combining stereotactic ablative radiotherapy and durvalumab (POSTCARD GETUG P13): Study protocol

BackgroundAs in other solid tumors, increasing evidence indicates that patients diagnosed with a limited number of prostate cancer metastases, so-called oligometastases, have a better prognosis than patients with extensive metastatic disease. Stereotactic body radiotherapy (SBRT) is now considered an option in this population.Programmed death-1 (PD-1) and its ligands (PD-L1) are targeted by immune checkpoint inhibitors. Preclinical studies have shown that the tumor immune microenvironment changes when combining radiotherapy with immunotherapy, especially with hypofractionated radiotherapy.The oligometastatic setting appears to be the most relevant clinical situation for evaluating the immune response generated by radiotherapy and immune checkpoint inhibitors in patients with an intact immune system.We hypothesize that durvalumab will enhance the immune response following SBRT targeting oligometastatic lesions. Our purpose is to demonstrate, via a randomized 2:1 phase II trial, that SBRT (3 fractions) with durvalumab in oligometastatic hormone-sensitive prostate cancer patients would improve progression-free survival in patients with prostate cancer with up to 5 metastases compared to patients who exclusively received SBRT. MethodsThis is a multicentric randomized phase II study in French academic hospitals. Patients with prostate cancer and up to 5 metastases (lymph node and/or bone) were randomized into a 2:1 ratio between Arm A (experimental group), corresponding to durvalumab and SBRT to the metastases, and Arm B (control group), corresponding to SBRT alone to the metastases. The study aims to accrue a total of 96 patients within 3 years. The primary endpoint is two-year progression-free survival and secondary endpoints include androgen deprivation therapy-free survival, quality of life, toxicity, prostate cancer specific survival, overall survival, and immune response. DiscussionThe expected benefit for the patients in the experimental arm is longer life expectancy with acceptable toxicity. We also expect our study to provide data for better understanding the synergy between immunotherapy and radiotherapy in oligometastatic prostate cancer.

The colorectal cancer-specific microbiome regulation and immune response activation via an artificial biomimetic nanovaccine

The tumor microbiome has been reported to be composed of tumor-type-specific intracellular bacteria and is closely related to tumor progression and the response to anticancer therapies. Although antitumor treatments focusing on the abnormal tumor microenvironment (TME), such as anti-bacterial or TME regulatory approaches, have been shown to significantly improve antitumor efficacy, strategies that can interfere with the microbial environment to inhibit tumor growth and activate immune response are rare. Here, we have constructed an artificially modified biomimetic nanovaccine PMO for the first time using an inactivated anaerobic bacterium P. anaerobius, a colorectal cancer (CRC)-specific bacterium carrying therapeutical agents to regulate the microbial environment. The PMO could sneak into tumors due to its natural affinity to CRC, which has a particularly rich and diverse microbiome that results in therapy resistance. The PMO could not only achieve significant tumor growth suppression by precisely delivering therapeutical MnO2 and OXA to CRC tissues but also effectively prevent tumor recurrence by the cascade reaction of activating the tumor immune responses after reshaping the microbial environment. This nanovaccine has provided the tremendous clinical potential for designing new treatment strategies for drug-resistant tumors from the perspective of microbial environmental regulation and improving the prognosis of patients.

Brief Research Report: Anti-SARS-CoV-2 Immunity in Long Lasting Responders to Cancer Immunotherapy Through mRNA-Based COVID-19 Vaccination.

Cancer patients (CPs) have been identified as particularly vulnerable to SARS-CoV-2 infection, and therefore are a priority group for receiving COVID-19 vaccination. From the patients with advanced solid tumors, about 20% respond very efficiently to immunotherapy with anti-PD1/PD-L1 antibodies and achieve long lasting cancer responses. It is unclear whether an efficient cancer-specific immune response may also correlate with an efficient response upon COVID-19 vaccination. Here, we explored the antiviral immune response to the mRNA-based COVID-19 vaccine BNT162b2 in a group of 11 long-lasting cancer immunotherapy responders. We analysed the development of SARS-CoV-2-specific IgG serum antibodies, virus neutralizing capacities and T cell responses. Control groups included patients treated with adjuvant cancer immunotherapy (IMT, cohort B), CPs not treated with immunotherapy (no-IMT, cohort C) and healthy controls (cohort A). The median ELISA IgG titers significantly increased after the prime-boost COVID vaccine regimen in all cohorts (Cohort A: pre-vaccine = 900 (100-2700), 3 weeks (w) post-boost = 24300 (2700-72900); Cohort B: pre-vaccine = 300 (100-2700), 3 w post-boost = 8100 (300-72900); Cohort C: pre-vaccine = 500 (100-2700), 3 w post-boost = 24300 (300-72900)). However, at the 3 w post-prime time-point, only the healthy control group showed a statistically significant increase in antibody levels (Cohort A = 8100 (900-8100); Cohort B = 900 (300-8100); Cohort C = 900 (300-8100)) (P < 0.05). Strikingly, while all healthy controls generated high-level antibody responses after the complete prime-boost regimen (Cohort A = 15/15 (100%), not all CPs behaved alike [Cohort B= 12/14 (84'6%); Cohort C= 5/6 (83%)]. Their responses, including those of the long-lasting immunotherapy responders, were more variable (Cohort A: 3 w post-boost (median nAb titers = 95.32 (84.09-96.93), median Spike-specific IFN-γ response = 64 (24-150); Cohort B: 3 w post-boost (median nAb titers = 85.62 (8.22-97.19), median Spike-specific IFN-γ response (28 (1-372); Cohort C: 3 w post-boost (median nAb titers = 95.87 (11.8-97.3), median Spike-specific IFN-γ response = 67 (20-84)). Two long-lasting cancer responders did not respond properly to the prime-boost vaccination and did not generate S-specific IgGs, neutralizing antibodies or virus-specific T cells, although their cancer immune control persisted for years. Thus, although mRNA-based vaccines can induce both antibody and T cell responses in CPs, the immune response to COVID vaccination is independent of the capacity to develop an efficient anti-cancer immune response to anti PD-1/PD-L1 antibodies.

Quantitative and qualitative impairments in dendritic cell subsets of patients with ovarian or prostate cancer

BackgroundDendritic cells (DCs) are the most efficient antigen-presenting cells, hence initiating a potent and cancer-specific immune response. This ability (mainly using monocyte-derived DCs) has been exploited in vaccination strategies for decades with limited clinical efficacy. Another alternative would be the use of conventional DCs (cDCs) of which at least three subsets circulate in human blood: cDC1s (CD141bright), cDC2s (CD1c+) and plasmacytoid DCs. Despite their paucity, technical advances may allow for their selection and clinical use. However, many assumptions concerning the DC subset biology depend on observations from mouse models, hindering their translational potential. In this study, we characterise human DCs in patients with ovarian cancer (OvC) or prostate cancer (PrC). Patients and methodsWhole blood samples from patients with OvC or PrC and healthy donors (HDs) were evaluated by flow cytometry for the phenotypic and functional characterisation of DC subsets. ResultsIn both patient groups, the frequency of total CD141+ DCs was lower than that in HDs, but the cDC1 subset was only reduced in patients with OvC. CD141+ DCs showed a reduced response to the TLR3 agonist poly (I:C) in both groups of patients. An inverse correlation between the frequency of cDC1s and CA125, the OvC tumour burden marker, was observed. Consistently, high expression of CLEC9A in OvC tissue (The Cancer Genome Atlas data set) indicated a better overall survival. ConclusionscDC1s are reduced in patients with OvC, and CD141+ DCs are quantitatively and qualitatively impaired in patients with OvC or PrC. CD141+ DC activation may predict functional impairment. The loss of cDC1s may be a bad prognostic factor for patients with OvC.

I-SABR phase II randomized study of nivolumab immunotherapy and stereotactic ablative radiotherapy in early stage NSCLC: Interim analysis adverse effects.

9035 Background: Stereotactic Ablative Radiotherapy (SABR) provides &gt; 95% local control and has become standard care of medically inoperable stage I NSCLC. However, cumulatively about 40% of patients develop recurrence in the regional lymph nodes, distant organs, or secondary lung cancer. Combined immunotherapy and SABR (I-SABR) may reduce these recurrences by stimulating stronger cancer specific immune response. Methods: This is an ongoing phase II randomized study (SABR vs. I-SABR) to evaluate the efficacy and toxicity of I-SABR in medically inoperable, early stage (T1-T3: &lt; 7 cm, including multi-primary tumors), isolated recurrence NSCLC without lymph node or distant metastasis. The primary objective is event-free survival (any recurrence and/or death). Secondary objectives include rates of ≥Grade 2 toxicity. 4-D CT image guided SABR (50 Gy in 4 fractions or 70 Gy in 10 fractions) was delivered to all patients. Patients randomized to I-SABR received additional concurrent Nivolumab (240 mg, every two weeks for total of 7 doses or 480 mg every four weeks for total of 4 doses). 140 patients are anticipated to enroll. We report here interim analysis of toxicity. Results: 92 patients (median age: 72, range: 57 to 90) were enrolled and randomized (47 to SABR; 45 to I-SABR). With median follow up of 14.5 months (range 2 to 28 months), there were no treatment-related grade 4/5 adverse events. For the I-SABR arm, there was one case of possible related grade 3 dyspnea, skin rash and 2 cases of probable grade 3 fatigue. There were possible/probable treatment related 2 cases of grade 2 pneumonitis, fatigue, pruritus and 1 case of grade 2 hyperthyroidism and arthralgia. No patients discontinued treatment due to adverse effects. For the SABR arm, there were possible treatment related 1 case of grade 2 fatigue and pneumonitis. All symptoms resolved with or without treatment. Conclusions: Combined Nivolumab immunotherapy and SABR (I-SABR) appear to be well-tolerated in this fragile patient population with no grade 4/5 toxicity. All toxicities were tolerable and resolved. The major barrier for patient enrollment and/or randomization is patient’s perception of potential toxicities and additional clinic visits. Continued enrollment and additional follow up are needed to validate these findings. Clinical trial information: NCT03110978.

Current Status of Chimeric Antigen Receptor T-Cell Therapy in Multiple Myeloma.

Multiple myeloma (MM) is an incurable malignancy of plasma cells. Recently multiple new therapeutic options have been introduced which was able to improve overall survival but ultimately patient become refractory specifically in patients with poor cytogenetics. Therefore, novel therapeutic options like immunotherapy are needed to improve outcomes. Chimeric antigen receptor (CAR) T-cell therapy is immunotherapy in which T cell are genetically engineered against a tumor-specific antigen and transfused back to the patient to mount major histocompatibility complex-independent cancer-specific immune response. The success of CAR T-cell therapy in lymphoid malignancies encouraged its development in MM. Most of the clinical studies target B-cell maturation antigen in relapsed refractory MM and relapse is the major issue. In this article, we will present the basics of CAR T-cell therapy, the most recent clinical and preclinical data, and we will discuss the future therapeutic realm of CAR T cells in MM.

Personalized medicine and back-allogeneic exosomes for cancer immunotherapy.

Extracellular vesicles, especially exosomes, have been explored for cancer immunotherapy. The initial studies made use of autologous B-cell or dendritic cell-derived exosomes, with the idea that MHC-peptide complexes on the exosomal surface would stimulate an MHC-restricted cancer-specific immune response. This was also verified in mouse systems, whilst the effects in human clinical systems were more modest. Several studies have explored the mechanisms for exosomal T-cell activation, and a picture emerges where the antigen-presenting cells, possibly both B cells and dendritic cells of the recipient, are needed to induce a potent T-cell response to exosomes. Therefore, the exosomes function more as an adjuvant-like delivery system of antigens, and we need to further understand the exact components that trigger the most broad and potent immune responses. Here, we describe the grounds for using allogeneic exosomes for cancer therapy, something that would greatly improve the feasibility of new exosome-based immunotherapeutic approaches to cure cancer.

Abstract 1505: Tumor associated antigen uptake tracking following immuno-radiotherapy

Abstract Immuno-radiotherapy is a promising strategy for generation of immunologic cancer recognition, rejection and induction of anti-cancer memory. Radiotherapy (RT) causes single or double strand DNA breaks in a dose dependent manner leading to immunogenic cell death of cancer cells and induction of type 1 interferons. Furthermore, RT increases MHCI expression on cancer cells and infiltration of cytotoxic T cells. Combined, these effects make RT a potent primer of anti-cancer immune responses. The most promising approaches in anti-cancer immunotherapy is to augment the adaptive immune response through danger associated molecular patterns signaling, including toll-like receptor (TLR) agonists. Optimally, these interventions should be given when tumor-associated antigen (TAA) uptake and presentation peaks. Previous studies on TAA uptake have mostly focused on in vitro or ex vivo assays to mimic the in vivo mechanisms. In the present study, we investigate the in vivokinetics of TAA uptake and trafficking using stably transfected mCherry-transfected B16F10 melanoma. B16F10 transfected with mCherry, a pH-stable fluorescent protein, allows tracking by e.g. flow cytometry in both cancer cells and phagocytosing populations. In vivo trafficking of mCherry fluorescence was investigated in mice treated with RT alone or in combination with TLR7 agonists given locally or systemically. Following treatment, TAA-uptake, -trafficking, and activation of relevant immune populations was evaluated in tumors or tumor draining lymph nodes (tdLNs). Increased TAA uptake was observed in MHCII high populations compared to MHCII low across all phagocytosing populations in tumors. The highest uptake (MFI of mCherry) was found in patrolling monocytes (CD11b+CD11c-Ly6c-CX3CR1high) and tumor-associated macrophages (CD11b+CD11c+CD64+). Interestingly, we exclusively found increased mCherry signal in resident cDC1s in tdLNs after treatment. RT led to a diminished population of migratory CD103+ cDC1s in tumors and we did not observe any increase in mCherry+ CD103+ cDC1s in tdLNs. We did not observe any mCherry signal in spleens - indicating that no cancer-specific immune response are mounted from the spleen. The results also indicate that TAA antigen is trafficked to tdLNs primarily by monocytes or by lymphatic drainage. Citation Format: Esben Christensen, Lars Ringgaard, Anja Brus, Andreas Kjaer, Anders E. Hansen, Thomas L. Andresen. Tumor associated antigen uptake tracking following immuno-radiotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1505.

Plasma-Induced Suppression of Recurrent and Reinoculated Melanoma Tumors in Mice

Plasma irradiation of cancer is expected to activate a cancer-specific immune response; however, its long-term systemic effect in animal models has not been sufficiently investigated. In this paper, the long-term systemic effect induced by plasma irradiation was examined using C57BL/6 mice inoculated with B16F10 melanoma. Melanoma tumors on the right hind legs of the mice were resected after treatment with nanosecond pulsed streamer discharge. The results showed that plasma treatment delayed the growth of recurrent tumors at the site of resection. In addition, plasma treatment delayed the growth of tumors reinoculated at the nonirradiated site on the left leg of the mice after resection. Histological and single-cell analyses revealed that plasma had no direct effect on primary tumors, whereas it enhanced cytotoxic T cell infiltration into reinoculated tumors. These results suggest that plasma treatment induces cancer-specific long-term immune memory in mice.

Abstract 4624: Natural killer cell licensing contributes to clearance of lung cancer

Abstract a) Natural Killer (NK) cell Inhibitory receptors function in a dichotomous role. Their engagement by MHC Class I upon encountering a target results in the inhibition of cytotoxicity. During NK development, however, their interaction with MHC Class I mediates the process of licensing or education, leading to an increase in responsiveness and cytotoxicity. For this reason the role of inhibitory receptors in controlling the clearance of MHC Class I+ solid tumors such as lung cancer is poorly defined. Since NK cells comprise the primary cytotoxic lymphocyte responsible for clearance of lung cancer, we set out to determine whether the licensing status of NK cells contributes to lung cancer susceptibility. b) Growth of MHC Class I+ murine lung cancer was evaluated in MHC Class I- mice, with unlicensed NK cells in direct comparison to MHC Class I+ mice with licensed NK cells. IFN-γ production was evaluated after plate bound antibody stimulation through the NKp46 and NKG2D pathways both flow cytometrically and by quantitative RT-PCR. Bone marrow transplantation was performed by injection of 10x106 unfractionated bone marrow cells after 500cGy irradiation and NK and CD4+ T cell depletion of recipient host. c) Injection of Lewis Lung Carcinoma (LLC) revealed a significant decrease in pulmonary tumor burden in mice with licensed NK cells (230.4±21.6 vs. 442.7±53.8 mg) that disappeared after NK depletion (421.4±36.8 vs. 421.9±66.3 mg). Freshly isolated licensed NK cells lysed LLC more robustly than unlicensed NK cells (28.7±.16% vs. 4.9±.2% specific lysis at 100:1 ratio respectively). Lung cancer expresses stress ligands recognized by NKG2D and NKp46 activating receptors. Licensed NK cells produced significantly more IFN-γ than their unlicensed counterparts after plate-bound stimulation with anti-NKp46 and anti-NKG2D (17.9±2.8% vs. 5.4±.8% respectively for dual NKp46 and NKG2D stimulation). No differences were evident between licensed and unlicensed NK cells in ribosomal mass, making it unlikely that translational defects were responsible for altered cytokine production. Licensing status also did not affect stability of IFN-γ but did affect mRNA levels. This suggests transcriptional control of licensing-mediated NK activity. IFN-γ production could be significantly increased in unlicensed NK cells by reintroduction of MHC Class I through non-myeloablative bone marrow transplantation from MHC Class I-sufficient congenic donors. Blockade of H2Kb-Ly49c (MHC Class I-inhibitory receptor) interaction during NK development in C57BL/6 mice using a non-depleting anti-Ly49c antibody (clone 4LO) decreased IFN-γ production in NK cells. d) The role of NK cell licensing and tumor-specific cytotoxicity is highly controversial. We now demonstrate that licensed NK cells mediate a superior lung cancer-specific immune response in a murine model. Our data suggests that altering the licensing status of NK cells may be an avenue of lung cancer-specific immunotherapy. Citation Format: Shi Lei, Kang Li, Saeed Arefanian, Alexander S. Krupnick. Natural killer cell licensing contributes to clearance of lung cancer [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 4624. doi:10.1158/1538-7445.AM2017-4624

Abstract MS1-2: MS1-2 Breast cancer immunotherapy: Building on clinical success

Abstract Breast cancer has long been considered immunologically silent, but it is now clear that the immune system is active in this disease. Breast cancers can naturally induce tumor infiltrating lymphocytes (TIL), which represent a biomarker of the endogenous immune response. Increasing data support the association of TIL with a better prognosis for breast cancer patients, and also suggest that the presence of TIL can predict response to standard breast cancer therapies. These observations have stimulated intense interest in harnessing the natural breast cancer-specific immune response for therapeutic benefit. Breast cancer vaccines that activate the breast cancer-specific immune response have been tested for many years, with minimal clinical success to date. This is likely due to both inadequate vaccination platforms and dominant mechanisms of immune suppression active within the breast tumor microenvironment. In the tumor microenvironment, the immune checkpoint pathway governed by the programmed cell death-1 (PD-1) receptor and its ligand PD-L1 has emerged as a significant mechanism of immune resistance in a variety of cancers, including breast cancer. Several monoclonal antibody antagonists of PD-1 or PD-L1 unleash the activity of tumor-specific T cells in multiple types of cancer, resulting in durable clinical responses that translate into an overall survival benefit. Early data in breast cancer reveal that these agents have activity in some patients with triple negative and estrogen receptor-positive breast cancer, with response rates that range from about 5-44%. Antagonists of the PD-1 pathway are typically well-tolerated in breast cancer patients, with unique immune-related adverse events that are quite manageable. Selecting patients for PD-L1 expression appears to enrich for responders to single agent therapies that target PD-1/PD-L1. Based on early clinical data, agents that target the PD-1 pathway are under accelerated clinical development for breast cancer treatment. The challenge moving forward is converting immunotherapy non-responders to responders. Combination immunotherapies that integrate standard breast cancer therapies and/or multiple innovative immune-based therapies to simultaneously promote T cell activity and relieve multiple mechanisms of immune suppression at the tumor site have the greatest potential for enhancing the clinical activity of immunotherapy for breast cancer patients. Citation Format: Emens LA. MS1-2 Breast cancer immunotherapy: Building on clinical success [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr MS1-2.

Abstract 2348: Nanovaccine : A novel immunotherapeutic strategy to treat bladder cancer

Abstract Introduction Bladder cancer is a significant healthcare problem. According to the National Cancer Institute, bladder cancer is the 6th most common type of cancer and represents 4.5% of total cancer patients in the U.S. Intravesical therapy with Bacillus Calmette-Guerin (BCG) vaccine is the gold standard for treating non-muscle invasive bladder cancer. However, BCG has several drawbacks. First, BCG is a tuberculosis vaccine, which often fails to trigger immune response against bladder cancer. This leads to low therapeutic efficacy and high recurrence rates. Secondly, intravesical injection is painful and causes urinary side effects, including burning sensation and increased frequency of urination. Therefore, a therapeutic regimen that can specifically treat bladder cancer and can be administered through other routes is highly needed. Immunotherapeutic strategy using nanoparticle can fulfill these needs. Polymeric nanoparticles encapsulating an immune adjuvant and co-injected with a tumor-associated antigen can trigger robust immune response against bladder cancer. Moreover, nanoparticles formulated using the FDA approved polymer poly (lactide-co-glycolide) (PLGA) is approved for human use and can be injected subcutaneously. Methods Nanoparticles encapsulating a novel imidazoquinoline derivative that activates both Toll-Like Receptor (TLR) 7 and 8 was used as vaccine adjuvants. These novel nanoparticle-encapsulated TLR agonists were used in combination with a model antigen, ovalbumin, to create the vaccine. This is referred to as nanovaccine in this study. C57BL/6 mice were vaccinated subcutaneously with 1-5 doses of the nanovaccine or various control treatments. Two days after the final vaccination dose, mice were sacrificed and organs were harvested. Splenocytes and lymphocytes were analyzed using flow cytometry. Results Nanovaccine improved dendritic cell activation in the lymph node. Frequency of co-stimulatory molecule CD80+ dendritic cells was two fold higher in the lymph node of vaccinated group. Greater activation of T cells and increased frequency of antigen-specific T cells were found in the spleen of vaccinated group. Antigen-specific CD44+ CD8 Tcell frequency was two fold higher in the vaccinated group. Nanovaccine elevated the frequency of both antigen-specific CD4 T cells and antigen-specific CD44+ CD4 T cells by ten fold. Conclusion Nanovaccine generated antigen-specific immune response that can maximize the efficacy of immunotherapy. Moreover, nanoparticles were physically stable and remained active after subcutaneous injection, which can overcome the administration difficulties of current BCG therapy. Next step is to generate nanovaccine with bladder tumor-specific antigen or using whole cell lysate and test the therapeutic efficacy in tumor bearing mice. Generation of a bladder cancer-specific immune response will allow stronger and durable inhibition of tumor growth and diminished risk of progression. Citation Format: Hyunjoon Kim, Lin Niu, Peter Larson, Katherine Murphy, Tamara Kucaba, David Ferguson, Thomas Griffith, Jayanth Panyam. Nanovaccine : A novel immunotherapeutic strategy to treat bladder cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2348.

Abstract A029: Cell-based cancer immunotherapy using tumor presenting cells: A phase II trial with local advance prostate cancer patients

Abstract We described a non-randomized control phase II trial, using a novel Cell Based Cancer Immunotherapy using Tumor Presenting Cells (TPC). The patient population was selected at HCPA – Porto Alegre Brazil (University Hospital). Patients with clinical localized prostate cancer and scheduled to undergo radical retro pubic prostatectomy (RRP) were identified. High-risk patients (initial PSA levels above 10 ng/ml, Gleason above 8 or upstaged from the clinical staging) were offer to participate on the trial. This group of patients represent a very important clinical population that cloud benefit from an adjuvant therapy. Tumor Presenting Cells are a new strategy for immunotherapy. Solid tumor cells as other non-immunological cells do not present MHC Class II. The MHC class II is a critical molecule responsible for peptide presentation to T helper cells. The presence of a not-self peptide on a MHC II molecule trigger the production of cytokines responsible for different steps on T cell expansion and maturation. Without the appropriate cytokine stimulation, cytotoxic T cells that identified a not-self peptide associate to a MHC class I molecules, may not proliferate or even be induce to anergy. In our model, solid tumor cells (prostate cancer) are induce to express MHCII on their surface. In this novel approach of Cell Based Cancer Immunotherapy (CBCI), patient's tumor cells were expanded in tissue culture and treated causing de novo expression of MHC II and activation of the MHC II peptide presentation pathway. Thus, the modified cancer cells are bifunctional, being capable of activating both helper T cells (MHC II) and cytotoxic T cells (MHCI), leading to cytokine production and a surprisingly robust and cancer-specific immune response. The modified solid tumor cell by itself will now behave as an antigen-presenting cell creating a Tumor Presenting Cell (TPC). Once the tumor cells are modified, they are irradiated and inoculated as intradermal injections (7 doses). Although the individualized preparation of CBCI is labor intensive, we were able to prepare the cell material on almost all collected samples (103/107 - 96%). DTH reactions (≥ 5 mm) were positive in 73% of the patients (16/23). This study corroborates with low toxicity of cell based immunotherapy. We have found mild skin reactions on inoculation sites in all vaccinated patients. More intense reactions (ulceration, low-grade fever, and adenopathy) were found in 13% of patients (3/23). We demonstrated a clinical benefit with the used of the CBCI: 27% (6/22) of the patients submitted to CBCI presented detectable levels of PSA (above 0.004 ng/mL) after 5 years, when compare to 53% (19/36) on the control group (p=0.03). There was also trend on reduction of cancer related mortality, 4% (1/23) on the CBCI group against 10% (4/40) on the control group. Several new therapies were approved in recent years for advanced prostate cancer treatment. The pharmaco-economic cost of these therapies are significant, and most of them shown an improvement survival of less than six months. New therapies such as Cell Base Cancer Immunotherapy with Tumor Presenting Cells could change this scenario, improving quality life, reducing mortality and cost to the health care providers. We are now designing a Phase III trial in North America for local advance prostate cancer. Other indication (triple negative breast cancer, pancreatic or gastric cancer patients) are also under evaluation. Citation Format: Fernando T. Kreutz. Cell-based cancer immunotherapy using tumor presenting cells: A phase II trial with local advance prostate cancer patients. [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 A029.

Heterologous, costimulation-assisted vaccinations drive potent cellular immune responses to cancer

Immunotherapy of cancer has emerged as an effective means for the treatment of solid cancer. The therapeutic efficacy of current therapies, however, is hampered by the low immunogenicity of the currently available vaccines that typically induce immune responses at or below the threshold of detection. Bacterial or viral vectors are able to overcome this limitation but require laborious vector design and are thus unsuitable for individually tailored vaccination approaches. We sought to develop a novel cancer vaccination that induces potent immune responses while preserving a maximum of flexibility with regard to the antigen of choice. Since co-stimulatory antibodies are potent stimulators of T cell expansion, we tested various combinations of agonistic costimulatory antibodies in combination with peptides and TLR agonists. We observed optimal CD8 T cell expansion when peptide vaccination was given in combination with the TLR3 agonist Poly I:C and CD40 agonistic antibodies. To enable short-term amplification of the cancer-specific immune response, we combined this costimulation-assisted vaccination with various primary immunizations. Surprisingly, the combination of the costimulation-based vaccination with a dendritic cell immunization led to massive amplification of CD8 T cell immune responses targeting either neoantigens or tumor-associated antigens. In therapeutic setting, the novel vaccination led to complete regression of subcutaneous tumor after vaccination against a single, high affinity antigen. Our results demonstrate that optimized prime-boost vaccinations are able to strongly amplify cancer-specific immune responses thus warranting their further evaluation for the immunotherapy of cancer patients.

Abstract 2515: Tumor presenting cells: a new strategy for cancer immunotherapy

Abstract Solid tumor cells as other non-immunological cells do not present MHC Class II. The MHC class II is a critical molecule responsible for peptide presentation to T helper cells. The presence of a not-self peptide on a MHC II molecule trigger the production of cytokines responsible for different steps on T cell expansion and maturation. Without the appropriate cytokine stimulation, cytotoxic T cells that identified a not-self peptide associate to a MHC class I molecules, may not proliferate or even be induce to anergy. We hypothesized that lack of anti-tumor immune responses on the majority of cancer patients (too little, too late) is due to a not appropriate MHC II peptide presentation. In our model, solid tumor cells (prostate cancer) are induce to express MHCII on their surface. In this novel approach of Cell Based Cancer Immunotherapy, patient's tumor cells were expanded in tissue culture and treated causing de novo expression of MHC II and activation of the MHC II peptide presentation pathway. Thus, the modified cancer cells are bifunctional, being capable of activating both helper T cells (MHC II) and cytotoxic T cells (MHCI), leading to cytokine production and a surprisingly robust and cancer-specific immune response. The modified solid tumor cell by itself will now behave as an antigen-presenting cell creating a Tumor Presenting Cell (TPC). As previous reported on a Phase IIb clinical trial done in Brazil (FK-Biotec/UFRGS/PUCRS), a population of local advance prostate cancer patients were treated with TPC. The study showed a significant (p = 0,03) increase in number of patients with undetectable levels of PSA (biochemical cure) after 5 years, 85% versus 48% on the control group. Also shown a trend of lowering mortality by prostate cancer, 9% in the threated group versus 19% in the control group. In conclusion, we are describing a novel Cell Based Cancer Immunotherapy that could be apply to several different tumor types. Citation Format: Fernando T. Kreutz. Tumor presenting cells: a new strategy for cancer immunotherapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2515. doi:10.1158/1538-7445.AM2015-2515

Editorial: Prostate Cancer: What We Know and What We Would Like to Know.

Cancer research has undergone radical changes over the last few years. The issue today is no longer the amount of molecular, cellular, and clinical information available, but how to handle it. Systems biology is the latest in a series of innovative strategies driven by technological advances that have provided us with a suite of “omics” (1). Technology advancements have enabled comprehensive characterization of genomic, epigenomic, transcriptomic, proteomic, and metabolomic alterations in tumor specimens (2). Despite this continuous progress, prostate cancer remains a major public health problem throughout the world (3). Among men, cancers of the prostate, lung and bronchus, and colon–rectum will account for about 50% of all newly diagnosed cancer (4). Prostate-specific antigen (PSA) is one of the most widely used tumor markers. Although its possible use in early diagnosis or screening PSA has various drawbacks mainly due to its low specificity (5) considering that more than half of the men with PSA over 4.0 ng/ml are negative on initial biopsy (6). A new generation of biomarkers is emerging, consisting of genomic-, serum-, urine-, and tissue-based assays that may supplement PSA testing, or replace it over time (7–9). Although the identification and development of more specific diagnostic biomarkers are considered important, the major focus in translational prostate cancer research is the identification of potential “quantitative variables” to detect clinically significant prostate cancers. As reported by Vlaeminck-Giullem et al. (10), the current dilemma is to specifically distinguish among all prostate tumors the very aggressive high-grade cancers that will become life threatening by developing extra-prostatic invasion and metastatic potential from the indolent cancers that will never modify a patient’s life expectancy. At molecular level, Src and other members of the Src kinase family have been proposed as potential candidates (10). Recently, it has been shown that the activation of Src-dependent intracellular pathways is frequently observed in clinically significant prostate cancer (11). The proto-oncogene tyrosine-protein kinase Src influences some of most important events that accompany tumor progression, including cell proliferation, cell motility, invasion, epithelial-to-mesenchymal transition, resistance to apoptosis, angiogenesis, neuroendocrine differentiation, and metastatic diffusion (11). The particularity of the Src oncogenic action in prostate carcinogenesis is its ability to interfere with the androgen pathway. Through both direct and indirect interaction with the androgen receptor (AR), Src reinforce the proliferative and anti-apoptotic actions of the AR, even in the absence of specific ligands. These molecular mechanisms constitute a solid rationale in favor of the use of Src inhibitors in managing patients with prostate cancer (10, 12). On the other hands, decades of research are now leading to therapeutics that target the molecular mechanisms of the cancer-specific immune response (13). These therapeutics include tumor antigen vaccines, dendritic cell activators, adjuvants that activate innate immunity, adoptive cellular therapy, and checkpoint blockade (13). Another major effort has been in prostate cancer prevention, where blockade of the testosterone metabolism pathway may be a major focus. However, the results of two large randomized, placebo-controlled trials: the prostate cancer prevention trial (PCPT) with finasteride and the reduction by dutasteride of prostate cancer events (REDUCE) trial have fueled controversies on the use of 5α-reductase inhibitors (5-ARI). Finasteride and dutasteride are among the agents used to target the androgen–AR axis to prevent the development and/or progression of prostate cancer, as summarized by Kosaka et al. (14). In particular, 5-ARIs have been shown to play a potential role in preventing clinical progression among men with low-risk prostate cancer on active surveillance. However, in light of the US Food and Drug Administration recommendation against 5-ARIs for primary chemoprevention, these findings should be interpreted with caution (3, 15).

Immunotherapy for the treatment of breast cancer.

Decades of research are now leading to therapeutics that target the molecular mechanisms of the cancer-specific immune response. These therapeutics include tumor antigen vaccines, dendritic cell activators, adjuvants that activate innate immunity, adoptive cellular therapy, and checkpoint blockade. The advances in targeted immunotherapy have led to clinical advances in the treatment of solid tumors such as melanoma, prostate cancer, lung cancer, and hematologic malignancies. Preclinical and translational studies suggest that patients with breast cancer may also benefit from augmenting effective immune responses. These results have led to early-phase clinical trials of tumor antigen vaccines, adjuvants, and combinations of checkpoint inhibitor blockade to boost breast cancer-specific immunity in patients. This review focuses on the current and emerging development of cancer immunotherapy for breast cancer.