ABSTRACT
The lack of synthesized information regarding biodiversity is a major problem among researchers, leading to a pervasive cycle where ecologists make field campaigns to collect information that already exists and yet has not been made available for a broader audience. This problem leads to long-lasting effects in public policies such as spending money multiple times to conduct similar studies in the same area. We aim to identify this knowledge gap by synthesizing information available regarding two Brazilian long-term biodiversity programs and the metadata generated by them. Using a unique dataset containing 1904 metadata, we identified patterns of metadata distribution and intensity of research conducted in Brazil, as well as where we should concentrate research efforts in the next decades. We found that the majority of metadata were about vertebrates, followed by plants, invertebrates, and fungi. Caatinga was the biome with least metadata, and that there's still a lack of information regarding all biomes in Brazil, with none of them being sufficiently sampled. We hope that these results will have implications for broader conservation and management guiding, as well as to funding allocation programs.
ABSTRACT
The study investigated the behavior of seventeen amino acids during spontaneous (SF) and starter culture (SC) fermentation of Criollo cocoa beans from Copallín, Guadalupe and Tolopampa, Amazonas-Peru. For this purpose, liquid chromatography (UHPLC) was used to quantify amino acids. Multivariate analysis was used to differentiate the phases of the fermentation process. The percentage of essential amino acids during SC fermentation (63.4%) was higher than SF (61.8%); it was observed that the starter culture accelerated their presence and increased their concentration during the fermentation process. The multivariate analysis identified a first stage (day 0 to day 2), characterized by a low content of amino acids that increased due to protein hydrolysis. The study showed that adding the starter culture (Saccharomyces cerevisiae) to the fermentation mass increased the concentration of essential amino acids (63.0%) compared to the spontaneous process (61.8%). Moreover, this addition reduced the fermentation time (3-4 days less), demonstrating that the fermentation process with a starter culture allows obtaining a better profile of amino acids precursors of flavor and aroma.
ABSTRACT
Açai seeds have been discarded improperly around the Amazonia region, but they can be seen as promising low-cost substrates for fermentation processes. The structural carbohydrates and physicochemical characterization of açai seeds from the Amazonia were assessed followed by the determination of the optimal hydrolysis conditions using H3PO4 (phosphoric acid) and H2SO4 (sulfuric acid) to obtain a liquor with high contents of simple carbohydrates and low levels of potential microbial inhibitors usually generated during acid hydrolysis of carbohydrates. A central composite rotational design was carried out varying the concentrations of diluted acid (0-5%, w/v), solids (0.1-25%, w/v), and hydrolysis time (9.5-110 min). Acid hydrolysis with H2SO4 was more effective in producing reducing sugars (15.9-103.1 g/L) than H3PO4 (2.9-33.9 g/L) during optimization. The optimal hydrolysis conditions with H2SO4 were 3.5% of acid (w/v), 25% of solids during 70 min at 121 °C, which provided a liquor with 55 g/L of reducing sugars and low levels of microbial inhibitors: acetic acid (1.8 g/L), hydroxymethyl furfural (338 mg/L), and furfural (10 mg/L). Thus, açai seeds were characterized as promising agroindustrial waste with high potential to be used as a low-cost substrate in biotechnological processes, comprising relevant environmental and bioeconomic aspects for the development of the Amazonia.
Subject(s)
Euterpe , Euterpe/chemistry , Hydrolysis , Furaldehyde/analysis , Carbohydrates/chemistry , Seeds/chemistry , Sugars/analysisABSTRACT
Millions of people in the world live in food insecurity, so identifying a tuber with characteristics capable of meeting the demand for food and also identifying active compounds that can be used to minimize harm to human health is of great value. The aim was to carry out a review based on systematic review tools and the main objective was to seek information on botanical, food, pharmacological, and phytochemical aspects of Casimirella sp. and propose possible applications. This review showed papers that addressed botanical, food, pharmacological, and phytochemical aspects of the Mairá-potato and presented suggestions for using this tuber allied to the information described in the works found in the Google Academic, Scielo, Science Direct, Scopus, PubMed, and Web of Science databases. This review synthesized knowledge about the Mairá-potato that can contribute to the direction of further research on the suggested technological applications, both on the use of this tuber as a polymeric material and its use as biomaterial, encapsulation, bioactive use, and 3D printing, because this work collected information about this non-conventional food plant (PANC) that shows great potential for use in various areas of study.
Subject(s)
Magnoliopsida , Solanum tuberosum , Humans , Food , Biocompatible Materials , Databases, Factual , Phytochemicals/pharmacologyABSTRACT
Melanoma is a skin cancer with a high mortality rate due to its invasive characteristics. Currently, immunotherapy and targeted therapy increase patient survival but are ineffective in the advanced stages of the tumor. Quercetin (Que) is a natural compound that has demonstrated chemopreventive effects against different types of tumors. This review provides evidence for the therapeutic potential of Que in melanoma and identifies its main targets. The Scopus, Web of Science, and PubMed databases were searched, and studies that used free or encapsulated Que in melanoma models were included, excluding associations, analogs, and extracts. As a result, 73 articles were retrieved and their data extracted. Que has multiple cellular targets in melanoma models, and the main regulated pathways are cell death, redox metabolism, metastasis, and melanization. Que was also able to regulate important targets of signaling pathways, such as PKC, RIG-I, STAT, and P53. In murine models, treatment with Que reduced tumor growth and weight, and decreased metastatic nodules and angiogenic vasculature. Several studies have incorporated Que into carriers, demonstrating improved efficacy and delivery to tumors. Thus, Que is a promising therapeutic agent for the treatment of melanoma; however, further studies are needed to evaluate its effectiveness in clinical trials.
Subject(s)
Melanoma , Skin Neoplasms , Humans , Animals , Mice , Melanoma/drug therapy , Skin Neoplasms/drug therapy , Quercetin/pharmacology , Quercetin/therapeutic use , Antioxidants/pharmacology , Antioxidants/therapeutic use , Melanoma, Cutaneous MalignantABSTRACT
Eryngium foetidum L. is an edible plant widespread in Amazonian cuisine and its leaves have high levels of promising phenolic compounds for the production of extracts to be used as natural antioxidant additives. In this study, the in vitro scavenging capacity of three freeze-dried extracts of E. foetidum leaves, obtained by ultrasound-assisted extraction using green solvents [water (H2O), ethanol (EtOH), and ethanol/water (EtOH/H2O)], was investigated against the most common reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated in both physiological and food systems. Six phenolic compounds were identified, chlorogenic acid (2198, 1816 and 506 µg/g) being the major compound for EtOH/H2O, H2O, and EtOH extracts, respectively. All E. foetidum extracts were efficient in scavenging all the ROS and RNS (IC50 = 45-1000 µg/mL), especially ROS. The EtOH/H2O extract showed the highest contents of phenolic compounds (5781 µg/g) and showed the highest efficiency in scavenging all the reactive species, with high efficiency for O2â¢- (IC50 = 45 µg/mL), except for ROOâ¢, for which EtOH extract was the most efficient. Therefore, E. foetidum leaf extracts, especially EtOH/H2O, showed high antioxidant potential to be used as natural antioxidants in food formulations and are promising for nutraceuticals products.
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The objective of this investigation was to develop a nutraceutical product, in bars, using defatted Brazil nut by-products. The methodological bases of analyses followed the guidelines of the Association of Official Analytical Chemists international and experimental tests of formulations. The bars presented with high protein content with high nutraceutical potential expressed as high levels of magnesium, sodium, calcium and potassium, with emphasis on selenium, supplying around 50% of the daily recommendations. The sulfur amino acids reach approximately the recommended chemical score (97%), the aromatic amino acids with a proportion close to 50% and those of the branched chain supplying the established recommendations for adults. In the sensory tests, the formulation that presented the best attributes and the greatest acceptance (91.78% for the flavor and 97.89% for the general impression) by the tasters was the bar formulation made with a 75:25 ratio of defatted Brazil nuts flour and isolated soy protein.
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Jambu (Acmella oleracea) is a vegetable used in human food. Drying is an alternative to increase the shelf life of the product. High temperatures can induce the degradation of carotenoids and reduce the health benefits of these compounds. This study investigated the effect of the Jambu leaves' drying temperature on the carotenoid composition. It was performed previously by screening 16 plants from different localities based on the total carotenoid content. The process of drying by convection was carried out at temperatures of 35, 40, 50, and 60 °C in an air circulation oven, at an air velocity of 1.4 m/s-1 and a processing time of ~20 h. The drying data were fitted to six mathematical models and the quantification of the carotenoid retention was determined by HPLC-DAD. The study demonstrates that the carotenoid content among the samples collected from the 16 producers varied by 72% (lower-175 ± 16 µg/g, higher-618 ± 46 µg/g). Among the models, the Page model was found to be the most suitable model to explain the variation of the experimental data. The drying process at 40 °C reduces the Jambu leaves' carotenoid content significantly (p < 0.05) (All-trans-ß-carotene-86 ± 2 µg/g, All-trans-lutein-141 ± 0.2 µg/g) but does not alter the carotenoid profile. The occurrence of similar reduction behavior was observed for the different carotenoids at all the temperatures studied. The drying process at 35 °C was the condition that ensured the highest retention of carotenoids, and also a product classified as a very high source of carotenoids (total carotenoids-748 ± 27 µg/g, vitamin A-17 ± 1 µg RAE/g). Thus, this study concludes that a temperature of 35 °C for 14 h (air velocity-1.4 m/s-1) is the best drying condition for Jambu leaves using a low-cost dryer and as a possibility for the preservation and marketing of this Amazonian raw material.
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Tucupi is a broth derived from cassava roots which is produced after the spontaneous fermentation of manipueira (the liquid portion obtained by pressing cassava roots), followed by cooking. This product is widely consumed along with traditional dishes in the Brazilian Amazonia and is already used in different places worldwide. In this study, tucupi obtained from the markets of Belém (Pará, Brazil) and produced using agroindustrial (11 samples) and non-agroindustrial (11 samples) units were investigated to determine their physicochemical characteristics, total and free HCN contents, and free bioactive amine profiles. Most of the samples showed significant variations (p ≤ 0.05) in pH (2.82-4.67), total acidity (0.14-1.36 g lactic acid/100 mL), reducing sugars (up to 2.33 g/100 mL), and total sugars (up to 4.35 g/100 mL). Regarding the amines, four biogenic amines (0.5-4.2 mg/L tyramine, 1.0-23.1 mg/L putrescine, 0.5-66.8 mg/L histamine, and 0.6-2.9 mg/L tryptamine) and one polyamine (0.4-1.7 mg/L spermidine) were identified in the tucupi samples. Even in the tucupi produced using the agroindustrial units, which had quality seals provided by the local regulatory agency, high levels of biogenic amines (4.4-78.2 mg/L) were observed, as well as high dosages of total (8.87-114.66 mg/L) and free (0.80-38.38 mg/L) HCN. These facts highlight the need for better knowledge regarding the product manufacturing process to establish standardization and high-quality conditions for tucupi processing since high contents of biogenic amines and HCN are commonly associated with adverse health effects.
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Arrabidaea chica, a medicinal plant found in the Amazon rainforest, is a promising source of bioactive compounds which can be used to inhibit oxidative damage in both food and biological systems. In this study, the in vitro scavenging capacity of characterized extracts of A. chica leaves, obtained with green solvents of different polarities [water, ethanol, and ethanol/water (1:1, v/v)] through ultrasound-assisted extraction, was investigated against reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide anion radicals (O2â¢-), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and peroxynitrite anion (ONOO-). The extract obtained with ethanol-water presented about three times more phenolic compound contents (11.8 mg/g) than ethanol and water extracts (3.8 and 3.6 mg/g, respectively), with scutellarein being the major compound (6.76 mg/g). All extracts showed high scavenging efficiency against the tested ROS and RNS, in a concentration-dependent manner with low IC50 values, and the ethanol-water extract was the most effective one. In addition, all the extracts were five times more efficient against ROO⢠than Trolox. Therefore, the extracts from A. chica leaves exhibited high promising antioxidant potential to be used against oxidative damage in food and physiological systems.
ABSTRACT
The use of yeasts as starter cultures is a promising alternative to produce fermented cacao with particular characteristics regarding the quality of aromas and physical and chemical characteristics that are accepted by the chocolate market. This study aimed to evaluate the physical and chemical transformations of cocoa beans during fermentation after inoculation with starter cultures of yeast species Pichia manshurica (PF) and Saccharomyces cerevisiae (SF), both previously isolated in cocoa bean fermentations in the Brazilian Amazon, in comparison with a fermentation without the inoculum addition (CF). During the fermentation time, which was carried out on a cocoa farm in Igarapé-Miri (Amazon biome, Pará, Brazil), the contents of phenolic compounds (catechin and epicatechin), sugars (glucose, fructose, and sucrose), acetic acid, and ethanol were monitored by HPLC, and the volatile compounds profiles were assessed by GC-MS. The starter culture of P. manshurica was able to produce fermented cocoa beans with highly desirable characteristics for the production of good quality chocolate: low acidity, a broad variety of aromatic compounds with floral, fruity, and sweet characteristics, in addition to showing high contents of catechin and epicatechin, which are known by their antioxidant properties. Therefore, the use of starter cultures with species of yeasts isolated in the Amazon region, during cocoa fermentation, is an alternative to obtain fermented seeds with high quality favoring the commercial agreements in the chocolate market by cocoa producers. PRACTICAL APPLICATION: The addition of starter cultures was able to produce cocoa beans with good quality. Yeasts species isolated and identified in Amazonian cocoa fermentation can improve the profiles of aromatic compounds. Catechin and epicatechin contents are higher in inoculated cocoa beans fermentations.
Subject(s)
Cacao , Catechin , Antioxidants , Cacao/chemistry , Ecosystem , Ethanol , Fermentation , Fructose , Glucose , Pichia , Saccharomyces cerevisiae , Sucrose , SugarsABSTRACT
Combination immunotherapy has emerged as a promising strategy to increase the immune response in glioblastoma (GBM) and overcome the complex immunosuppression occurring in its microenvironment. In this study, we hypothesized that combining DNA vaccines-to stimulate a specific immune response-and dual immune checkpoint blockade (ICB)-to decrease the immunosuppression exerted on T cells-will improve the immune response and the survival in an orthotopic unresectable GL261 model. We first highlighted the influence of the insertion position of a GBM epitope sequence in a plasmid DNA vaccine encoding a vesicular stomatitis virus glycoprotein (VSV-G) (here referred to as pTOP) in the generation of a specific and significant IFN-γ response against the GBM antigen TRP2 by inserting a CD8 epitope sequence in specific permissive sites. Then, we combined the pTOP vaccine with anti-PD-1 and anti-CTLA-4 ICBs. Immune cell analysis revealed an increase in effector T cell to Treg ratios in the spleens and an increase in infiltrated IFN-γ-secreting CD8 T cell frequency in the brains following combination therapy. Even if the survival was not significantly different between dual ICB and combination therapy, we offer a new immunotherapeutic perspective by improving the immune landscape in an orthotopic unresectable GBM model.
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Oncolytic Viruses (OVs) work through two main mechanisms of action: the direct lysis of the virus-infected cancer cells and the release of tumor antigens as a result of the viral burst. In this sc.enario, the OVs act as in situ cancer vaccines, since the immunogenicity of the virus is combined with tumor antigens, that direct the specificity of the anti-tumor adaptive immune response. However, this mechanism in some cases fails in eliciting a strong specific T cell response. One way to overcome this problem and enhance the priming efficiency is the production of genetically modified oncolytic viruses encoding one or more tumor antigens. To avoid the long and expensive process related to the engineering of the OVs, we have exploited an approach based on coating OVs (adenovirus and vaccinia virus) with tumor antigens. In this work, oncolytic viruses encoding tumor antigens and tumor antigen decorated adenoviral platform (PeptiCRAd) have been used as cancer vaccines and evaluated both for their prophylactic and therapeutic efficacy. We have first tested the oncolytic vaccines by exploiting the OVA model, moving then to TRP2, a more clinically relevant tumor antigen. Finally, both approaches have been investigated in tumor neo-antigens settings. Interestingly, both genetically modified oncolytic adenovirus and PeptiCRAd elicited T cells-specific anti-tumor responses. However, in vitro cross-representation experiments, showed an advantage of PeptiCRAd as regards the fast presentation of the model epitope SIINFEKL from OVA in an immunogenic rather than tolerogenic fashion. Here two approaches used as cancer oncolytic vaccines have been explored and characterized for their efficacy. Although the generation of specific anti-tumor T cells was elicited in both approaches, PeptiCRAd retains the advantage of being rapidly adaptable by coating the adenovirus with a different set of tumor antigens, which is crucial in personalized cancer vaccines clinical setting.
Subject(s)
Cancer Vaccines , Neoplasms , Oncolytic Virotherapy , Oncolytic Viruses , Adenoviridae , Antigens, Neoplasm , Humans , Oncolytic Viruses/genetics , Peptides , Precision Medicine , Vaccines, SubunitABSTRACT
There is scarce information regarding lactic acid bacteria (LAB) and the production of biogenic amines during manipueira fermentation for tucupi. Thus, the objective of this study was to isolate and identify LAB, and to determine their impact on bioactive amine formation. Spontaneous fermentation of manipueira was carried out at laboratory scale and selected LAB colonies were isolated and identified by sequencing techniques and comparison with sequences from a virtual database. Only two LAB species of the genus Lactobacillus were identified during fermentation: Lactobacillus fermentum and Lactobacillus plantarum. L. fermentum was the predominant, whereas L. plantarum was only detected in manipueira prior to fermentation. Spermidine and putrescine were detected throughout fermentation, whereas histamine was produced at the final stage. There was positive correlation between LAB counts and putrescine and histamine levels, suggesting that the identified LAB are responsible for the synthesis of these amines during manipueira fermentation. Genetic assays are needed to verify whether the LAB identified have the genes responsible for decarboxylation of amino acids.
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Bromodomain and extraterminal domain protein inhibitors (BETi) for cancer treatment did not convince during their first clinical trials. Their epigenetic mechanism of action is still not well understood, even if MYC is generally considered as its main downstream target. In this context, we intended to assess two new nanoformulations of the BETi JQ1 for the treatment of colorectal cancer (CRC). JQ1 was encapsulated at 10 mg/mL in lipid nanocapsules (LNC) or polymeric micelles (PM), both compatible for an intravenous administration. Their effect was compared with free JQ1 on several CRC cell lines in vitro and with daily intraperitoneal cyclodextrin (CD)-loaded JQ1 on the CT26 CRC tumor model in vivo. We showed that LNC preferentially accumulated in tumor, liver, and lymph nodes. LNC-JQ1 and CD-JQ1 similarly delayed tumor growth and increased median survival from 15 to 23 or 20.5 days. JQ1 altered MYC in only two among four CRC cell lines. This MYC-independence found in CT26 was confirmed in vivo by PCR and immunohistochemistry. The main explanation of the JQ1 anticancer effect was an increase in apoptosis. The investigation of its impact on the tumor microenvironment did not show significant effects. Finally, JQ1 association with irinotecan did not synergize in vivo with JQ1 nanoformulations. In conclusion, we demonstrated that the JQ1 anticancer effect was not improved by nanoencapsulation even if their tumor delivery was probably higher. MYC inhibition was not associated to JQ1 efficacy in the case of the CT26 CRC murine model.
Subject(s)
Antineoplastic Agents/pharmacology , Azepines/pharmacology , Colorectal Neoplasms/drug therapy , Liposomes , Nanoparticles , Proteins/antagonists & inhibitors , Triazoles/pharmacology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/therapeutic use , Azepines/administration & dosage , Azepines/therapeutic use , Cell Line, Tumor/drug effects , Colorectal Neoplasms/metabolism , Drug Delivery Systems , Female , Humans , Infusions, Intravenous , Mice , Mice, Inbred BALB C , Proto-Oncogene Proteins c-myc/metabolism , Triazoles/administration & dosage , Triazoles/therapeutic useABSTRACT
This study evaluated the effect of convective drying on the degradation of color and phenolic compounds of purple basil (Ocimum basilicum L.) leaves, and the hygroscopic behavior of dried leaves. The fresh leaves underwent drying at 40 °C, 50 °C, 60 °C, and 70 °C. Degradation of chlorophyll, flavonoids, and phenolic compounds were evaluated during drying and the hygroscopicity was evaluated through the moisture sorption isotherms. The drying mathematical modeling and the moisture sorption data were performed. The effective diffusivity for the drying increased from 4.93 × 10−10 m2/s at 40 °C to 18.96 × 10−10 m2/s at 70 °C, and the activation energy value (39.30 kJ/mol) showed that the leaves present temperature sensibility. The leaves dried at 40 °C had less degradation of phenolic compounds and color variation, but the drying process was too slow for practical purposes. Modified Page, Diffusion Approximation, and Verna models had excellent accuracy in drying kinetics. The isotherms showed that, in environments with relative humidity above 50%, the purple basil leaves are more susceptible to water gain, and at 8.83 g H2O/100 g db moisture, it guarantees the microbiological stability of the dried leaves. The Oswin model was the most suitable for estimating the moisture sorption isotherms of the dried leaves.
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Carotenoids are natural lipophilic pigments mainly found in plants, but also found in some animals and can be synthesized by fungi, some bacteria, algae, and aphids. These pigments are used in food industries as natural replacements for artificial colors. Carotenoids are also known for their benefits to human health as antioxidants and some compounds have provitamin A activity. The production of carotenoids by biotechnological approaches might exceed yields obtained by extraction from plants or chemical synthesis. Many microorganisms are carotenoid producers; however, not all are industrially feasible. Therefore, in this review, we provide an overview regarding fungi that are potentially interesting to industry because of their capacity to produce carotenoids in response to stresses on the cultivation medium, focusing on low-cost substrates.
Subject(s)
Antioxidants/metabolism , Biotechnology/methods , Carotenoids/metabolism , Genetic Engineering , Animals , Humans , Substrate SpecificityABSTRACT
In addition to the vast diversity of fauna and flora, the Brazilian Amazon has different climatic periods characterized by periods with greater and lesser rainfall. The main objective of this research was to verify the influence of climatic seasons in the Brazilian Amazon (northeast of Pará state) concerning the aromatic and bioactive profiles of fermented and dried cocoa seeds. About 200 kg of seeds was fermented using specific protocols of local producers. Physicochemical analyzes (total titratable acidity, pH, total phenolic compounds, quantification of monomeric phenolics and methylxanthines) and volatile compounds by GC-MS were carried out. We observed that: in the summer, the highest levels of aldehydes were identified, such as benzaldehyde (6.34%) and phenylacetaldehyde (36.73%), related to the fermented cocoa and honey aromas, respectively; and a total of 27.89% of this same class was identified during winter. There were significant differences (p ≤ 0.05, Tukey test) in the profile of bioactive compounds (catechin, epicatechin, caffeine, and theobromine), being higher in fermented almonds in winter. This study indicates that the climatic seasons in the Amazon affect the aromatic and bioactive profiles and could produce a new identity standard (summer and winter Amazon) for the cocoa almonds and their products.
Subject(s)
Cacao , Ecosystem , Flavonoids , Phenols , Seasons , Seeds , Cacao/chemistry , Cacao/metabolism , Flavonoids/chemistry , Flavonoids/metabolism , Odorants , Phenols/chemistry , Phenols/metabolism , Seeds/chemistry , Seeds/metabolismABSTRACT
This study aimed to characterize the relationship between the COX2 and ALOX5 genes, as well as their link with the multidrug resistance (MDR) phenotype in sensitive (K562) and MDR (K562-Lucena and FEPS) erythroleukemia cells. For this, the inhibitors of 5-LOX (zileuton) and COX-2 (acetylsalicylic acid-ASA) and cells with the silenced ABCB1 gene were used. The treatment with ASA caused an increase in the gene expression of COX2 and ABCB1 in both MDR cell lines, and a decrease in the expression of ALOX5 in the FEPS cells. Silencing the ABCB1 gene induced a decrease in COX2 expression and an increase in the ALOX5 gene. Treatment with zileuton did not alter the expression of COX2 and ABCB1. Cytometry data showed that there was an increase in ABCB1 protein expression after exposure to ASA. In addition, the increased activity of ABCB1 in the K562-Lucena cell line indicates that ASA may be a substrate for this efflux pump, corroborating the molecular docking that showed that ASA can bind to ABCB1. Regardless of the genetic alteration in COX2 and ABCB1, the direct relationship between these genes and the inverse relationship with ALOX5 remained in the MDR cell lines. We assume that ABCB1 can play a regulatory role in COX2 and ALOX5 during the transformation of the parental cell line K562, explaining the increased gene expression of COX2 and decreased ALOX5 in the MDR cell lines.
Subject(s)
Cyclooxygenase 2ABSTRACT
BACKGROUND: Strategies to increase nucleic acid vaccine immunogenicity are needed to move towards clinical applications in oncology. In this study, we designed a new generation of DNA vaccines, encoding an engineered vesicular stomatitis virus glycoprotein as a carrier of foreign T cell tumor epitopes (plasmid to deliver T cell epitopes, pTOP). We hypothesized that pTOP could activate a more potent response compared with the traditional DNA-based immunotherapies, due to both the innate immune properties of the viral protein and the specific induction of CD4 and CD8 T cells targeting tumor antigens. This could improve the outcome in different tumor models, especially when the DNA-based immunotherapy is combined with a rational therapeutic strategy. METHODS: The ability of pTOP DNA vaccine to activate a specific CD4 and CD8 response and the antitumor efficacy were tested in a B16F10-OVA melanoma (subcutaneous model) and GL261 glioblastoma (subcutaneous and orthotopic models). RESULTS: In B16F10-OVA melanoma, pTOP promoted immune recognition by adequate processing of both MHC-I and MHC-II epitopes and had a higher antigen-specific cytotoxic T cell (CTL) killing activity. In a GL261 orthotopic glioblastoma, pTOP immunization prior to tumor debulking resulted in 78% durable remission and long-term survival and induced a decrease of the number of immunosuppressive cells and an increase of immunologically active CTLs in the brain. The combination of pTOP with immune checkpoint blockade or with tumor resection improved the survival of mice bearing, a subcutaneous melanoma or an orthotopic glioblastoma, respectively. CONCLUSIONS: In this work, we showed that pTOP plasmids encoding an engineered vesicular stomatitis virus glycoprotein, and containing various foreign T cell tumor epitopes, successfully triggered innate immunity and effectively promoted immune recognition by adequate processing of both MHC-I and MHC-II epitopes. These results highlight the potential of DNA-based immunotherapies coding for viral proteins to induce potent and specific antitumor responses.