Post-radiation xerostomia therapy with allogeneic mesenchymal stromal stem cells in patients with head and neck cancer: study protocol for phase I clinical trial.

BACKGROUND: Xerostomia is a common side effect of radiotherapy in patients with head and neck tumors that negatively affects quality of life. There is no known effective standard treatment for xerostomia. Here, we present the study protocol used to evaluate the safety and preliminary efficacy of allogeneic mesenchymal stromal stem cells (MSCs) derived from umbilical cord tissue. PATIENTS AND METHODS: Ten oropharyngeal cancer patients with post-radiation xerostomia and no evidence of disease recurrence 2 or more years after (chemo)irradiation (intervention group) and 10 healthy volunteers (control group) will be enrolled in this nonrandomized, open-label, phase I exploratory study. MSCs from umbilical cord tissue will be inserted under ultrasound guidance into both parotid glands and both submandibular glands of the patients. Toxicity of the procedure will be assessed according to CTCAE v5.0 criteria at days 0, 1, 5, 28, and 120. Efficacy will be assessed by measuring salivary flow and analyzing its composition, scintigraphic evaluation of MSC grafting, retention, and migration, and questionnaires measuring subjective xerostomia and quality of life. In addition, the radiological, functional, and morphological characteristics of the salivary tissue will be assessed before, at 4 weeks, and at 4 months after the procedure. In the control group subjects, only salivary flow rate and salivary composition will be determined. DISCUSSION: The use of allogeneic MSCs from umbilical cord tissue represents an innovative approach for the treatment of xerostomia after radiation. Due to the noninvasive collection procedure, flexibility of cryobanking, and biological advantages, xerostomia therapy using allogeneic MSCs from umbilical cord tissue may have an advantage over other similar therapies.

Combined TLR-3/TLR-8 Signaling in the Presence of α-Type-1 Cytokines Represents a Novel and Potent Dendritic Cell Type-1, Anti-Cancer Maturation Protocol.

During the ex vivo generation of anti-cancer dendritic cell (DC)-based vaccines, their maturation still represents one of the most crucial steps of the manufacturing process. A superior DC vaccine should: possess extensive expression of co-stimulatory molecules, have an exceptional type-1 polarization capacity characterized by their ability to produce IL-12p70 upon contact with responding T cells, migrate efficiently toward chemokine receptor 7 (CCR7) ligands, and have a superior capacity to activate cytotoxic T cell responses. A major advance has been achieved with the discovery of the next generation maturation protocol involving TLR-3 agonist (poly I:C), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, interferon (IFN)-γ, and IFN-α, and has since been known as α-type-1 maturation cocktail. We demonstrate how this combination can be greatly enhanced by the inclusion of a TLR-8 stimulation (R848), thereby contributing to potentiation between different TLR signaling pathways. For maximum efficiency, TLR-3 stimulation should precede (termed pre I:C) the stimulation with the R848/TNF-α/IL-1ß/IFN-α/IFN-γ cocktail. When compared to DCs matured with α-type-1 maturation cocktail (αDCs), DCs matured with pre I:C/R848/TNF-α/IL-1ß/IFN-α/IFN-γ (termed zDCs) displayed higher expression of CD80 and CD86 co-stimulatory molecules. Importantly, after CD40-ligand stimulation, which simulates DC-T cell contact, zDCs were much more proficient in IL-12p70 production. In comparison to αDCs, zDCs also displayed a significantly greater migratory capacity toward chemokine ligands (CCL)19 and CCL21, and had a significantly greater allo-stimulatory capacity. Finally, zDCs were also superior in their capacity to induce melanoma-specific CD8+ T cells, CD8+ T cell proliferation, and cytotoxic T cells, which produced approximately two times more IFN-γ and more granzyme B, than those stimulated with αDCs. In conclusion, we present a novel and superior DC maturation cocktail that could be easily implemented into next generation DC vaccine manufacturing protocols in future trials.

Programmed death ligand 1 (PD-L1) plays a vital part in DC tolerogenicity induced by IFN-γ.

Interferon-γ (IFN-γ) is the sole representative of type II IFNs, with well recognized role in numerous inflammatory processes. Lately, its significant pleiotropic nature has been recognized in many scenarios, where IFN-γ contributes to maintenance or induction of tolerogenic responses in context of various immune cell types. In this manuscript we demonstrate, that IFN-γ-mediated induction of programmed death ligand 1 (PD-L1) on human monocyte-derived dendritic cells (DCs) represents an important tolerogenic aspect in immunological network of type II IFNs. When fully differentiated, immature DCs were treated with increasing concentrations of IFN-γ there was no sign of maturation, as revealed by CD80, CD83 and CD86 expression. In terms of co-stimulatory receptor response, we did observe a dose-dependent increase in CD40 expression. Phenotypic analysis of inhibitory molecules revealed that PD-L1 expression is particularly sensitive to IFN-γ, as its expression can be induced almost 10-fold in comparison to non-treated DCs. Functional analysis of such PD-L1high DCs revealed significant immunosuppressive properties in a mixed lymphocyte reaction with whole or memory CD4+ T cells. When IFN-γ treated DCs were co-cultured with naive CD4+CD45RA+ T cells, they induced an increased percentage of CD4+CD25+CD127-FoxP3+ Tregs. Inhibition of PD-1/PD-L1 axis using neutralizing anti-PD-L1 mAbs, reversed the immunosuppressive effect of IFN-γ-treated DCs to suppress CD4+ T cell proliferation and to induce Tregs. In summary, our findings demonstrate the importance of IFN-γ-mediated tolerogenic effects, exerted on DCs by inducing increased expression of PD-L1, which enhances their regulatory function.

Overview of Cellular Immunotherapies within Transfusion Medicine for the Treatment of Malignant Diseases.

Over the years, transfusion medicine has developed into a broad, multidisciplinary field that covers different clinical patient services such as apheresis technology and the development of stem cell transplantation. Recently, the discipline has found a niche in development and production of advanced therapy medicinal products (ATMPs) for immunotherapy and regenerative medicine purposes. In clinical trials, cell-based immunotherapies have shown encouraging results in the treatment of multiple cancers and autoimmune diseases. However, there are many parameters such as safety, a high level of specificity, and long-lasting efficacy that still need to be optimized to maximize the potential of cell-based immunotherapies. Thus, only a few have gained FDA approval, while the majority of them are studied in the context of investigator-initiated trials (IITs), where modern, academically oriented transfusion centers can play an important role. In this review, we summarize existing and contemporary cellular immunotherapies, which are already a part of modern transfusion medicine or are likely to become so in the future.

Dendritic Cells Generated in the Presence of Platelet Lysate Have a Reduced Type 1 Polarization Capacity.

Previously, we have shown platelet lysate (PL) can be used as a non-xenogeneic serum supplement for generation of monocyte-derived dendritic cells (DCs). Since DC-based activation protocols are extremely sensitive to microenvironmental changes such as replacement of culture medium, we wanted to examine the behavior of DCs cultured in the presence of PL under various type-1 activation conditions and assess their type 1 polarization capacity. We compared the quality of DCs cultured in 10% PL-supplemented RPMI medium (plDCs) with clinical-grade DCs obtained using commercially available serum-free medium (sfDCs), frequently used in established DC vaccine protocols. The DC maturation protocols consisted of either monophosphoryl lipid A/IFN-γ, poly I:C/TNF-α/IFN-α or poly I:C/R848. In general, plDCs were inferior to sfDCs in most aspects of their functional type 1 polarization characteristics. After maturation, the expression of co-stimulatory, HLA class II and lymph node-homing molecules was strongly up-regulated, with some noticeable differences. The expression of CD80 and CD86 was more extensive on plDCs, which was particularly evident in case of CCR7. However, after observing their functional capacity, plDCs had significantly lower allo-stimulatory capacity both in terms of CD4+ and CD8+ T cell stimulation. The high expression of CCR7 corresponded to higher CCL-19 directed DC migration of plDCs compared to sfDCs. Finally, their capacity to induce granzyme B and IFN-γ production in CD8+ T cells was significantly reduced in comparison to sfDCs. Based on these findings, the use of PL as an alternative serum supplement for generation of monocyte-derived DC anti-tumor vaccines is questionable.Abbreviations: Ag: antigen; CCL: chemokine ligand; CCR: chemokine receptor; DC: dendritic cells; DC-SIGN: dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin; FBS: fetal bovine serum; GMP: good manufacturing practice; IFN: interferon; IL: interleukin; MPLA: monophosphoryl lipid A; PGE: prostaglandin E; pI:C: polyinosinic:polycytidylic acid; pl: platelet lysate; sf: serum free; TLR: toll-like receptor; TNF: tumor necrosis factor.

Clinically Usable Interleukin 12 Plasmid without an Antibiotic Resistance Gene: Functionality and Toxicity Study in Murine Melanoma Model.

Plasmids, which are currently used in interleukin 12 (IL-12) gene electrotransfer (GET) clinical trials in the USA, contain antibiotic resistance genes and are thus, according to the safety recommendation of the European Medicines Agency (EMA), not suitable for clinical trials in the EU. In the current study, our aim was to prepare an IL-12 plasmid without an antibiotic resistance gene and test its functionality and toxicity after GET in a preclinical B16F10 mouse melanoma model. The antibiotic resistance-free plasmid encoding the human IL-12 fusion gene linked to the p21 promoter, i.e., p21-hIL-12-ORT, was constructed using operator-repressor titration (ORT) technology. Next, the expression profile of the plasmid after GET was determined in B16F10 cells and tumors. Additionally, blood chemistry, hematological and histological changes, and antitumor response were evaluated after GET of the plasmid in melanoma tumors. The results demonstrated a good expression and safety profile of the p21-hIL-12-ORT GET and indications of efficacy. We hope that the obtained results will help to accelerate the transfer of this promising treatment from preclinical studies to clinical application in the EU.

Tailor-made fibroblast-specific and antibiotic-free interleukin 12 plasmid for gene electrotransfer-mediated cancer immunotherapy.

Electrotransfer mediated delivery of interleukin-12 (IL-12) gene, encoded on a plasmid vector, has already been demonstrated to have a potent antitumor efficacy and great potential for clinical application. In the present study, our aim was to construct an optimized IL-12-encoding plasmid that is safe from the regulatory point of view. In light of previous studies demonstrating that IL-12 should be released in a tumor localized manner for optimal efficacy, the strong ubiquitous promoter was replaced with a weak endogenous promoter of the collagen 2 gene, which is specific for fibroblasts. Next, to comply with increasing regulatory demands for clinically used plasmids, the expression cassette was cloned in a plasmid lacking the antibiotic resistance gene. The constructed fibroblast-specific and antibiotic-free IL-12 plasmid was demonstrated to support low IL-12 expression after gene electrotransfer in selected cell lines. Furthermore, the removal of antibiotic resistance did not affect the plasmid expression profile and lowered its cytotoxicity. With optimal IL-12 expression and minimal transgene non-specific effects, i.e., low cytotoxicity, the constructed plasmid could be especially valuable for different modern immunological approaches to achieve localized boosting of the host's immune system.

Endoglin (CD105) Silencing Mediated by shRNA Under the Control of Endothelin-1 Promoter for Targeted Gene Therapy of Melanoma.

Endoglin (CD105), a transforming growth factor (TGF)-ß coreceptor, and endothelin-1, a vasoconstrictor peptide, are both overexpressed in tumor endothelial and melanoma cells. Their targeting is therefore a promising therapeutic approach for melanoma tumors. The aim of our study was to construct a eukaryotic expression plasmid encoding the shRNA molecules against CD105 under the control of endothelin-1 promoter and to evaluate its therapeutic potential both in vitro in murine B16F10-luc melanoma and SVEC4-10 endothelial cells and in vivo in mice bearing highly metastatic B16F10-luc tumors. Plasmid encoding shRNA against CD105 under the control of the constitutive U6 promoter was used as a control. We demonstrated the antiproliferative and antiangiogenic effects of both plasmids in SVEC4-10 cells, as well as a moderate antitumor and pronounced antimetastatic effect in B16F10-luc tumors in vivo. Our results provide evidence that targeting melanoma with shRNA molecules against CD105 under the control of endothelin-1 promoter is a feasible and effective treatment, especially for the reduction of metastatic spread.

Improved Specificity of Gene Electrotransfer to Skin Using pDNA Under the Control of Collagen Tissue-Specific Promoter.

In order to ensure safe, efficient and controlled gene delivery to skin, the improvement of delivery methods together with proper design of DNA is required. Non-viral delivery methods, such as gene electrotransfer, and the design of tissue-specific promoters are promising tools to ensure the safety of gene delivery to the skin. In the scope of our study, we evaluated a novel skin-specific plasmid DNA with collagen (COL) promoter, delivered to skin cells and skin tissue by gene electrotransfer. In vitro, we determined the specificity of the COL promoter in fibroblast cells. The specific expression under the control of COL promoter was obtained for the reporter gene DsRed as well as for therapeutic gene encoding cytokine IL-12. In vivo, the plasmid with COL promoter encoding the reporter gene DsRed was efficiently transfected to mouse skin. It resulted in the notable and controlled manner, however, in lower and shorter expression, compared to that obtained with ubiquitous promoter. The concentration of the IL-12 in the skin after the in vivo transfection of plasmid with COL promoter was in the same range as after the treatment in control conditions (injection of distilled water followed by the application of electric pulses). Furthermore, this gene delivery was local, restricted to the skin, without any evident systemic shedding of IL-12. Such specific targeting of skin cells, observed with tissue-specific COL promoter, would improve the effectiveness and safety of cutaneous gene therapies and DNA vaccines.

In vitro targeted gene electrotransfer to endothelial cells with plasmid DNA containing human endothelin-1 promoter.

Development of recombinant DNA technologies has allowed us to create new delivery systems that target specific cell types and that can be used in gene therapy. One of these targets is vascular endothelium because of its important role in tumor angiogenesis. For tumor endothelium-specific targeting, we prepared plasmid DNA encoding green fluorescent protein under the control of human endothelin-1 promoter (pENDO-EGFP), which is specific for endothelial cells. First we determined gene electrotransfer parameters for improved transfection of endothelial cells evaluating different osmolarity of electroporation buffer, voltages of applied electric pulses, and addition of fetal bovine serum immediately after electroporation to the cells for improved transfection and survival. Transfection efficacy of pENDO-EGFP in different endothelial and nonendothelial cell lines was determined next. Gene electrotransfer efficacy was evaluated using three different methods: fluorescence microscopy, fluorescence microplate reader, and flow cytometry. Our results showed that transfection efficacy was higher when cells were prepared in hypoosmolar compared to isoosmolar electroporation buffer. Furthermore, immediate addition of fetal bovine serum to the cells after pulsing also improved gene electrotransfer into target cells. We proved expression of EGFP under the control of human endothelin-1 promoter in endothelial cells, which was also significantly higher compared to nonendothelial cells. Taken together, we successfully constructed pENDO-EGFP, which was specifically expressed in endothelial cells using improved gene electrotransfer parameters.