Proof of Concept Study: Mesoporous Silica Nanoparticles, From Synthesis to Active Specific Immunotherapy

Nanomaterials are increasingly valued tools in drug delivery research as they offer enhanced stability, controlled release and more effective drug encapsulation. Though yet to be introduced in clinical trial, mesoporous silica nanoparticles are promising delivery systems, due to their high chemical and mechanical stability while remaining biodegradable. This work provides proof of concept for particle based vaccines as cost-effective alternatives for dendritic cell immunotherapy. Synthesis and surface chemistry of the nanoparticles are optimized for protein conjugation and nanoparticles are characterized for their physicochemical properties and biodegradation. Ovalbumin is used as a model protein to load nanoparticles to produce a nanovaccine. The vaccine is tested in vitro on dendritic cultures to verify particle and vaccine uptake, toxicity, maturation effects and explicitly ovalbumin cross-presentation on MHC class I molecules. The optimized synthesis protocol renders reproducible mesoporous silica nanoparticles, resistant against agglomeration, within the required size range and have carboxylic surface functionalization necessary for protein conjugation. They are biodegradable over a time span of 1 week. This period is adjustable by changing synthesis parameters. UV sterilization of the particles does not induce quality loss, nor does it have toxic effects on cells. Treatment with mesoporous silica nanoparticles increases expression of MHC and costimulatory molecules of dendritic cells, indicating an adjuvant effect of nanoparticles on the adaptive immune system. Nanovaccine uptake and cross-presentation of ovalbumin are observed and the latter is increased when delivered by nanoparticles as compared to control conditions. This confirms the large potential of mesoporous silica nanoparticle based vaccines to replace dendritic-based active specific immunotherapy, offering a more standardized production process and higher efficacy.

Active Specific Immunotherapy (ASI) and Gcmaf Forte in Management of Metastatic Invasive Carcinoma–Overview of the Therapeutic Modalities and A Case Report

Metastatic cancer is often a fatal disease with low survival rate that in a course of its progression implies a pathogenic cascade involving inflammation, overexpression of reactive oxygen species, loss of DNA repair, genome instability, neoangiogenesis, epithelial infiltration, collagen destruction, and immunosuppression and apoptosis evasion by cancer cells. Understanding the cross-interaction mechanism between the immune co-stimulatory and inhibitory molecules on one side and tumors cells is a key point in the development of a successful immunotherapeutic strategy to fight aggressive cancers. The Active Specific Immunotherapy (ASI) and the GC protein Macrophage Activating Factor (GcMAF) are two immunotherapies capable of modulating the innate and adaptive immunity against cancer. The aim of this work is to present a case of an invasive metastatic carcinoma treated with ASI and GcMAF Forte and discuss the potentials of the individualized immunotherapy in advanced forms of cancer. Immunotherapy improves status of immune system and as a result it increases patient’s life span (and probably survival rate). In conclusion, the ASI and GcMAF Forte may offer a promising prospective immunological biomedical approach to boost immunity and enhance life expectancy in patients with metastatic cancer.

PERSPECTIVES IN ACTIVE SPECIFIC IMMUNOTHERAPY WITH AUTOLOGOUS IMMATURE DENDRITIC CELLS COMBINED WITH PHOTODYNAMIC THERAPY AND CYCLOPHOSPHAMIDE IN PATIENTS WITH DISSEMINATED MELANOMA RESISTANT TO STANDARD THERAPY

There are described the results of clinical and immunological efficacy assessment of active specific immunotherapy with autologous immature dendritic cells (DC) combined with photodynamic therapy (PDT) and cyclophosphamide (C) in disseminated melanoma patients, resistant to standard therapy. 27 patients treated in the N.N. Petrov Research Institute of Oncology were included in the study from 2007 till 2016. Immunotherapy was conducted in a 21-day cycles. Therapy included following steps: 1) preparation of individual vaccine preparation from bone-marrow derived DC with immune phenotype CD34-/CD14VCD1a+/CD83VCD80-/+/CD86-/+/HLA-DR+; 2) Intramuscular 300 mg C injection in day 1 of treatment cycle for elimination T-lymphocytes with immunosuppressing activity; 3) PDT with chlorin salts at day 4 six hours before start of vaccinotherapy; 4) Daily intralesional injections of DC vatccine in irradiated lesions in the dose 1х106 DC cells/ kg. Clinical and immunological efficacy was assessed in 27 patients. Fourteen (52%) patients received 1-2 cycles of therapy, 13(48%) received 3 or more cycles. No complete response was seen. Partial response (RECIST 1.1) was found in 2 (7,4%) patients, stable disease in 8 (29,6%) patients. Seventeen (63%) patients progressed. Median time to progression (TTP) was 2.5 month, median overall survival (OS) 8.4 month. One-year survival was 5% and 37% for TTP and OS, respectively. No adverse events (AE) of grade 4-5 (CTC AE v4) were seen. Grade 3 fever was registered in 4% of patients. Grade 1-2 AE were found in 54% of patients. Immunologic assessment revealed significant decline of immunoregulatory index (CD/ CD8) caused by prevalence of cytotoxic T-lymphocytes in peripheral blood of responding patients (patients with clinical benefit). Tendency for elevation of absolute number of activates T-helpers and cytotoxic T-lymphocytes together with low T-regulatory cells concentration was also found. Combination therapy using immunomodulatory effects of C, PDT and DC vaccine in 21-day treatment cycles produce promising activity and favorable toxicity profile in heavily pretreated disseminated melanoma patients.