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The COVID-19 pandemic and the need for additional safe, effective, and affordable vaccines gave new impetus into development of vaccine genetic platforms. Here we report the findings from the phase 1, first-in-human, dose-escalation study of COVID-eVax, a DNA vaccine encoding the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Sixty-eight healthy adults received two doses of 0.5, 1, or 2 mg 28 days apart, or a single 2-mg dose, via intramuscular injection followed by electroporation, and they were monitored for 6 months. All participants completed the primary safety and immunogenicity assessments after 8 weeks. COVID-eVax was well tolerated, with mainly mild to moderate solicited adverse events (tenderness, pain, bruising, headache, and malaise/fatigue), less frequent after the second dose, and it induced an immune response (binding antibodies and/or T cells) at all prime-boost doses tested in up to 90% of the volunteers at the highest dose. However, the vaccine did not induce neutralizing antibodies, while particularly relevant was the T cell-mediated immunity, with a robust Th1 response. This T cell-skewed immunological response adds significant information to the DNA vaccine platform and should be assessed in further studies for its protective capacity and potential usefulness also in other therapeutic areas, such as oncology.
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COVID-19 , Vacunas de ADN , Adulto , Humanos , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Método Doble Ciego , Pandemias/prevención & control , SARS-CoV-2 , Vacunas de ADN/efectos adversosRESUMEN
The COVID-19 pandemic caused by SARS-CoV-2 has made the development of safe and effective vaccines a critical priority. To date, four vaccines have been approved by European and American authorities for preventing COVID-19, but the development of additional vaccine platforms with improved supply and logistics profiles remains a pressing need. Here we report the preclinical evaluation of a novel COVID-19 vaccine candidate based on the electroporation of engineered, synthetic cDNA encoding a viral antigen in the skeletal muscle. We constructed a set of prototype DNA vaccines expressing various forms of the SARS-CoV-2 spike (S) protein and assessed their immunogenicity in animal models. Among them, COVID-eVax-a DNA plasmid encoding a secreted monomeric form of SARS-CoV-2 S protein receptor-binding domain (RBD)-induced the most potent anti-SARS-CoV-2 neutralizing antibody responses (including against the current most common variants of concern) and a robust T cell response. Upon challenge with SARS-CoV-2, immunized K18-hACE2 transgenic mice showed reduced weight loss, improved pulmonary function, and lower viral replication in the lungs and brain. COVID-eVax conferred significant protection to ferrets upon SARS-CoV-2 challenge. In summary, this study identifies COVID-eVax as an ideal COVID-19 vaccine candidate suitable for clinical development. Accordingly, a combined phase I-II trial has recently started.
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Vacunas contra la COVID-19/administración & dosificación , COVID-19/prevención & control , Inmunización/métodos , Modelos Animales , SARS-CoV-2/aislamiento & purificación , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunas de ADN/administración & dosificación , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/genética , COVID-19/virología , Femenino , Hurones , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Dominios Proteicos , Ratas Sprague-DawleyRESUMEN
COVID-19 has rapidly spread all over the world, progressing into a pandemic. This situation has urgently impelled many companies and public research institutes to concentrate their efforts on research for effective therapeutics. Here, we outline the strategies and targets currently adopted in developing a vaccine against SARS-CoV-2. Based on previous evidence and experience with SARS and MERS, the primary focus has been the Spike protein, considered as the ideal target for COVID-19 immunotherapies.
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Betacoronavirus/inmunología , Infecciones por Coronavirus/prevención & control , Pandemias/prevención & control , Neumonía Viral/prevención & control , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/efectos adversos , Anticuerpos Antivirales/biosíntesis , Acrecentamiento Dependiente de Anticuerpo/inmunología , Betacoronavirus/genética , Betacoronavirus/patogenicidad , COVID-19 , Vacunas contra la COVID-19 , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/genética , Infecciones por Coronavirus/inmunología , Humanos , Neumonía Viral/epidemiología , Neumonía Viral/inmunología , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Investigación Biomédica Traslacional , Vacunas Virales/efectos adversos , Vacunas Virales/genéticaRESUMEN
BACKGROUND: Tracking the genetic variability of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) is a crucial challenge. Mainly to identify target sequences in order to generate robust vaccines and neutralizing monoclonal antibodies, but also to track viral genetic temporal and geographic evolution and to mine for variants associated with reduced or increased disease severity. Several online tools and bioinformatic phylogenetic analyses have been released, but the main interest lies in the Spike protein, which is the pivotal element of current vaccine design, and in the Receptor Binding Domain, that accounts for most of the neutralizing the antibody activity. METHODS: Here, we present an open-source bioinformatic protocol, and a web portal focused on SARS-CoV-2 single mutations and minimal consensus sequence building as a companion vaccine design tool. Furthermore, we provide immunogenomic analyses to understand the impact of the most frequent RBD variations. RESULTS: Results on the whole GISAID sequence dataset at the time of the writing (October 2020) reveals an emerging mutation, S477N, located on the central part of the Spike protein Receptor Binding Domain, the Receptor Binding Motif. Immunogenomic analyses revealed some variation in mutated epitope MHC compatibility, T-cell recognition, and B-cell epitope probability for most frequent human HLAs. CONCLUSIONS: This work provides a framework able to track down SARS-CoV-2 genomic variability.
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COVID-19/virología , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Sitios de Unión/genética , COVID-19/epidemiología , Vacunas contra la COVID-19/genética , Biología Computacional , Minería de Datos , Variación Genética , Humanos , Fenómenos Inmunogenéticos , Modelos Moleculares , Mutación , Pandemias/estadística & datos numéricos , Dominios Proteicos , Receptores Virales , SARS-CoV-2/inmunología , Programas Informáticos , Glicoproteína de la Espiga del Coronavirus/inmunología , Investigación Biomédica TraslacionalRESUMEN
BACKGROUND: There are no accepted universal biomarkers capable to accurately predict response to immuno-checkpoint inhibitors (ICI). Although recent literature has been flooded with studies on ICI predictive biomarkers, available data show that currently approved companion diagnostics either leave out many possible responders, as in the case of PD-L1 testing for first-line metastatic lung cancer, or apply to a small subset of patients, such as the recently approved treatment for microsatellite instability-high or mismatch repair deficiency tumors. In this study, we conducted a survey of the available data on ICI trials with matched genomic or transcriptomic datasets in order to cross-validate the proposed biomarkers, to assess whether their prediction power was confirmed and, mainly, to investigate if their combination was able to generate a better predictive tool. METHODS: We extracted clinical information and sequencing data details from publicly available datasets, along with a list of possible biomarkers obtained from the recent literature. After an operation of data harmonization, we validated the performance of all the biomarkers taken individually. Furthermore, we tested two strategies to combine the best performing biomarkers in order to improve their predictive value. RESULTS: When considered individually, some of the biomarkers, such as the ImmunoPhenoScore, and the IFN-γ signature, did not confirm their originally proposed predictive power. The best absolute scoring biomarkers are TIDE, one of the ICB resistance signatures and CTLA4 with a mean AUC > 0.66. Among the combinations tested, generalized linear models showed the best performance with an AUC of 0.78. CONCLUSIONS: We confirmed that the available biomarkers, taken individually, fail to provide a satisfactory predictive value. Unfortunately, also combination of some of them only provides marginal improvements. Hence, in order to generate a more robust way to predict ICI efficacy it is necessary to analyze and combine additional biomarkers and interrogate a wider set of clinical data.
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Biomarcadores de Tumor/metabolismo , Inmunoterapia , Área Bajo la Curva , Genes Relacionados con las Neoplasias , Humanos , Curva ROCAsunto(s)
Betacoronavirus/inmunología , Infecciones por Coronavirus/prevención & control , Pandemias/prevención & control , Neumonía Viral/prevención & control , Vacunas de ADN/efectos adversos , Vacunas de ADN/inmunología , Vacunas Virales/uso terapéutico , COVID-19 , Infecciones por Coronavirus/virología , ADN Viral/genética , Humanos , Inmunogenicidad Vacunal , Neumonía Viral/virología , Reacción en Cadena de la Polimerasa/métodos , SARS-CoV-2 , Vacunación , Vacunas de ADN/economía , Vacunas Virales/inmunologíaRESUMEN
According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN-γ or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines.
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Antígenos de Neoplasias/inmunología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica/inmunología , Neoplasias Ováricas/inmunología , Células TH1/inmunología , Adulto , Anciano , Apoptosis/inmunología , Supervivencia Celular , Células Dendríticas/inmunología , Femenino , Humanos , Interferón gamma/biosíntesis , Interleucina-17/biosíntesis , Persona de Mediana Edad , Neoplasias Ováricas/tratamiento farmacológico , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Células Tumorales CultivadasRESUMEN
The kinesin spindle protein (KSP), a member of the kinesin superfamily of microtubule-based motors, plays a critical role in mitosis as it mediates centrosome separation and bipolar spindle assembly and maintenance. Inhibition of KSP function leads to cell cycle arrest at mitosis with the formation of monoastral microtubule arrays, and ultimately, to cell death. Several KSP inhibitors are currently being studied in clinical trials and provide new opportunities for the development of novel anticancer therapeutics. RNA interference (RNAi) may represent a powerful strategy to interfere with key molecular pathways involved in cancer. In this study, we have established an efficient method for intratumoral delivery of siRNA. We evaluated short interfering RNA (siRNA) duplexes targeting luciferase as surrogate marker or KSP sequence. To examine the potential feasibility of RNAi therapy, the siRNA was transfected into pre-established lesions by means of intratumor electro-transfer of RNA therapeutics (IERT). This technology allowed cell permeation of the nucleic acids and to efficiently knock down gene expression, albeit transiently. The KSP-specific siRNA drastically reduced outgrowth of subcutaneous melanoma and ovarian cancer lesions. Our results show that intratumoral electro-transfer of siRNA is feasible and KSP-specific siRNA may provide a novel strategy for therapeutic intervention.
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Cinesinas/metabolismo , Neoplasias Experimentales/terapia , ARN Interferente Pequeño , Animales , Línea Celular Tumoral , Electroporación , Femenino , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Proteínas Fluorescentes Verdes , Humanos , Cinesinas/genética , Masculino , Melanoma , Ratones , Ratones Desnudos , Neoplasias Ováricas , Interferencia de ARNRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of the COVID-19 pandemic, has been shown to infect a wide range of animal species, especially mammals, and besides human-to-human transmission, human-to-animal transmission has also been observed in some wild animals and pets, especially in cats. It has been demonstrated that cats are permissive to COVID-19 and are susceptible to airborne infections. Given the high transmissibility potential of SARS-CoV-2 to different host species and the close contact between humans and animals, it is crucial to find mechanisms to prevent the transmission chain and reduce the risk of spillover to susceptible species. Here, we show results from a clinical trial conducted in domestic cats to assess safety and immunogenicity of a linear DNA (linDNA) vaccine encoding the receptor-binding domain (RBD) from SARS-CoV-2 (Lin-COVID-eVax). Lin-COVID-eVax proved to be safe, with no significant adverse events, and was able to elicit both RBD-specific antibodies and T cells. Also, the linDNA vaccine induced neutralizing antibody titers against ancestral SARS-CoV-2 virus and its variants. These findings demonstrate the safety and immunogenicity of a genetic vaccine against COVID-19 administered to cats and strongly support the development of vaccines for preventing viral spread in susceptible species, especially those in close contact with humans.
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DNA integrity is a key issue in gene therapy and genetic vaccine approaches based on plasmid DNA. In contrast to messenger RNA that requires a controlled cold chain for efficacy, DNA molecules are considered to be more stable. In this study, we challenged this concept by characterizing the immunological response induced by a plasmid DNA vaccine delivered using electroporation. As a model, we used COVID-eVax, a plasmid DNA-based vaccine that targets the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Increased nicked DNA was produced by using either an accelerated stability protocol or a lyophilization protocol. Surprisingly, the immune response induced in vivo was only minimally affected by the percentage of open circular DNA. This result suggests that plasmid DNA vaccines, such as COVID-eVax that have recently completed a phase I clinical trial, retain their efficacy upon storage at higher temperatures, and this feature may facilitate their use in low-/middle-income countries.
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Immune checkpoint inhibitors (ICI) based on anti-CTLA-4 (αCTLA-4) and anti-PD1 (αPD1) are being tested in combination with different therapeutic approaches including other immunotherapies such as neoantigen cancer vaccines (NCV). Here we explored, in two cancer murine models, different therapeutic combinations of ICI with personalized DNA vaccines expressing neoantigens and delivered by electroporation (EP). Anti-cancer efficacy was evaluated using vaccines with or without CD4 epitopes. Therapeutic DNA vaccines showed synergistic effects in different therapeutic protocols including established large tumors. Flow cytometry (FC) was utilized to measure CD8, CD4, Treg, and switched B cells as well as neoantigen-specific immune responses, which were also measured by IFN-γ ELIspot. Immune responses were augmented in combination with αCTLA4 but not with αPD1 in the MC38 tumor-bearing mice, significantly impacting tumor growth. Similarly, neoantigen-specific T cell immune responses were enhanced in combined treatment with αCTLA-4 in the CT26 tumor model where large tumors regressed in all mice, while monotherapy with αCTLA-4 was less efficacious. In line with previous evidence, we observed an increased switched B cells in the spleen of mice treated with αCTLA-4 alone or in combination with NCV. These results support the use of NCV delivered by DNA-EP with αCTLA-4 and suggest a new combined therapy for clinical testing.
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The COVID-19 pandemic is entering a new era with the approval of many SARS-CoV-2 vaccines. In spite of the restoration of an almost normal way of life thanks to the immune protection elicited by these innovative vaccines, we are still facing high viral circulation, with a significant number of deaths. To further explore alternative vaccination platforms, we developed COVID-eVax-a genetic vaccine based on plasmid DNA encoding the RBD domain of the SARS-CoV-2 spike protein. Here, we describe the correlation between immune responses and the evolution of viral infection in ferrets infected with the live virus. We demonstrate COVID-eVax immunogenicity as means of antibody response and, above all, a significant T-cell response, thus proving the critical role of T-cell immunity, in addition to the neutralizing antibody activity, in controlling viral spread.
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BACKGROUND: DNA-based vaccines represent a simple, safe and promising strategy for harnessing the immune system to fight infectious diseases as well as various forms of cancer and thus are considered an important tool in the cancer immunotherapy toolbox. Nonetheless, the manufacture of plasmid DNA vaccines has several drawbacks, including long lead times and the need to remove impurities from bacterial cultures. Here we report the development of polymerase chain reaction (PCR)-produced amplicon expression vectors as DNA vaccines and their in vivo application to elicit antigen-specific immune responses in animal cancer models. METHODS: Plasmid DNA and amplicon expression was assessed both in vitro, by Hela cells transfection, and in vivo, by evaluating luciferase expression in wild-type mice through optical imaging. Immunogenicity induced by DNA amplicons was assessed by vaccinating wild-type mice against a tumor-associated antigen, whereas the antitumoral effect of DNA amplicons was evaluated in a murine cancer model in combination with immune-checkpoint inhibitors (ICIs). RESULTS: Amplicons encoding tumor-associated-antigens, such as telomerase reverse transcriptase or neoantigens expressed by murine tumor cell lines, were able to elicit antigen-specific immune responses and proved to significantly impact tumor growth when administered in combination with ICIs. CONCLUSIONS: These results strongly support the further exploration of the use of PCR-based amplicons as an innovative immunotherapeutic approach to cancer treatment.
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Vacunas contra el Cáncer , Neoplasias , Vacunas de ADN , Animales , Antígenos de Neoplasias , ADN , Células HeLa , Humanos , Inmunoterapia/métodos , Ratones , Neoplasias/tratamiento farmacológico , Neoplasias/terapiaRESUMEN
Cancer is a heterogeneous disease and its treatment remains unsatisfactory with inconstant therapeutic responses. This variability could be related, at least in part, to different and highly personalized gut microbiota compositions. Different studies have shown an impact of microbiota on antitumor therapy. It has been demonstrated that some gut bacteria influences the development and differentiation of immune cells, suggesting that different microbiota compositions could affect the efficacy of the antitumor vaccine. Emerging data suggest that recognition of neoantigens for the generation of neoantigen cancer vaccines (NCVs) could have a key role in the activity of clinical immunotherapies. However, it is still unknown whether there is a crosstalk between microbiota and NCV. This study aimed to understand the possible mechanisms of interaction between gut microbiota and NCV delivered by DNA-electroporation (DNA-EP). We found that decreased microbiota diversity induced by prolonged antibiotic (ATB) treatment is associated with higher intratumor specific immune responses and consequently to a better antitumor effect induced by NCV delivered by DNA-EP.
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Vacunas contra el Cáncer , Microbiota , Neoplasias , Antígenos de Neoplasias , Electroporación , Inmunoterapia , Neoplasias/tratamiento farmacológicoRESUMEN
BACKGROUND: Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol (GPI) anchored protein expressed not only in prostate but also in pancreas and bladder cancer as shown by immunohistochemistry and mRNA analysis. It has been targeted by monoclonal antibodies in preclinical animal models and more recently in a clinical trial in prostate cancer patients. The biological role played in tumor growth is presently unknown. In this report we have characterized the contribution of PSCA expression to tumor growth. METHODS: A bladder cell line was engineered to express a doxycycline (dox) regulated shRNA against PSCA. To shed light on the PSCA biological role in tumor growth, microarray analysis was carried out as a function of PSCA expression. Expression of gene set of interest was further analyzed by qPCR RESULTS: Down regulation of the PSCA expression was associated with reduced cell proliferation in vitro and in vivo. Mice bearing subcutaneous tumors showed a reduced tumor growth upon treatment with dox, which effectively induced shRNA against PSCA as revealed by GFP expression. Pathway analysis of deregulated genes suggests a statistical significant association between PSCA downregulation and activation of genes downstream of the IFNalpha/beta receptor. CONCLUSIONS: These experiments established for the first time a correlation between the level of PSCA expression and tumor growth and suggest a role of PSCA in counteracting the natural immune response.
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Glicoproteínas de Membrana/biosíntesis , Proteínas de Neoplasias/biosíntesis , Neoplasias de la Vejiga Urinaria/patología , Animales , Antígenos de Neoplasias , Procesos de Crecimiento Celular/fisiología , Línea Celular Tumoral , Células Clonales , Regulación hacia Abajo , Doxiciclina/farmacología , Femenino , Proteínas Ligadas a GPI , Humanos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Desnudos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/inmunología , Reacción en Cadena de la Polimerasa , Interferencia de ARN , Transducción de Señal/inmunología , Transcripción Genética , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/inmunología , Neoplasias de la Vejiga Urinaria/metabolismoRESUMEN
BACKGROUND: Spontaneous tumors in dog have been demonstrated to share many features with their human counterparts, including relevant molecular targets, histological appearance, genetics, biological behavior and response to conventional treatments. Mammary tumors in dog therefore provide an attractive alternative to more classical mouse models, such as transgenics or xenografts, where the tumour is artificially induced. To assess the extent to which dog tumors represent clinically significant human phenotypes, we performed the first genome-wide comparative analysis of transcriptional changes occurring in mammary tumors of the two species, with particular focus on the molecular pathways involved. RESULTS: We analyzed human and dog gene expression data derived from both tumor and normal mammary samples. By analyzing the expression levels of about ten thousand dog/human orthologous genes we observed a significant overlap of genes deregulated in the mammary tumor samples, as compared to their normal counterparts. Pathway analysis of gene expression data revealed a great degree of similarity in the perturbation of many cancer-related pathways, including the 'PI3K/AKT', 'KRAS', 'PTEN', 'WNT-beta catenin' and 'MAPK cascade'. Moreover, we show that the transcriptional relationships between different gene signatures observed in human breast cancer are largely maintained in the canine model, suggesting a close interspecies similarity in the network of cancer signalling circuitries. CONCLUSION: Our data confirm and further strengthen the value of the canine mammary cancer model and open up new perspectives for the evaluation of novel cancer therapeutics and the development of prognostic and diagnostic biomarkers to be used in clinical studies.
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Neoplasias de la Mama/genética , ADN de Neoplasias/genética , Perfilación de la Expresión Génica , Neoplasias Mamarias Animales/genética , Animales , Análisis por Conglomerados , Hibridación Genómica Comparativa , Biología Computacional , Modelos Animales de Enfermedad , Enfermedades de los Perros/genética , Perros , Regulación Neoplásica de la Expresión Génica , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Análisis de Componente PrincipalRESUMEN
BACKGROUND: Personalized cancer vaccines based on neoantigens have reached the clinical trial stage in melanoma. Different vaccination protocols showed efficacy in preclinical models without a clear indication of the quality and the number of neoantigens required for an effective cancer vaccine. METHODS: In an effort to develop potent and efficacious neoantigen-based vaccines, we have developed different neoantigen minigene (NAM) vaccine vectors to determine the rules for a successful neoantigen cancer vaccine (NCV) delivered by plasmid DNA and electroporation. Immune responses were analyzed at the level of single neoantigen by flow cytometry and correlated with tumor growth. Adoptive T cell transfer, from HLA-2.1.1 mice, was used to demonstrate the efficacy of the NCV pipeline against human-derived tumors. RESULTS: In agreement with previous bodies of evidence, immunogenicity was driven by predicted affinity. A strong poly-functional and poly-specific immune response was observed with high affinity neoantigens. However, only a high poly-specific vaccine vector was able to completely protect mice from subsequent tumor challenge. More importantly, this pipeline - from the selection of neoantigens to vaccine design - applied to a new model of patient derived tumor xenograft resulted in therapeutic treatment. CONCLUSIONS: These results suggest a feasible strategy for a neoantigen cancer vaccine that is simple and applicable for clinical developments.
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Antígenos de Neoplasias/inmunología , Vacunas contra el Cáncer/inmunología , Medicina de Precisión/métodos , Animales , Femenino , Vectores Genéticos , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
In the advent of Immune Checkpoint inhibitors (ICI) and of CAR-T adoptive T-cells, the new frontier in Oncology is Cancer Immunotherapy because of its ability to provide long term clinical benefit in metastatic disease in several solid and liquid tumor types. It is now clear that ICI acts by unmasking preexisting immune responses as well as by inducing de novo responses against tumor neoantigens. Thanks to theprogress made in genomics technologies and the evolution of bioinformatics, neoantigens represent ideal targets, due to their specific expression in cancer tissue and the potential lack of side effects. In this review, we discuss the promise of preclinical and clinical results with mutation-derived neoantigen cancer vaccines (NCVs) along with the current limitations from bioinformatics prediction to manufacturing an effective new therapeutic approach.
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Vacunas contra el Cáncer/uso terapéutico , Inmunoterapia/métodos , Medicina de Precisión/métodos , Antígenos de Neoplasias , Vacunas contra el Cáncer/farmacología , HumanosRESUMEN
DNA repair gene expression in a set of gastric cancers suggested an inverse association between the expression of the mismatch repair (MMR) gene MLH1 and that of the base excision repair (BER) gene DNA polymerase ß (Polß). To gain insight into possible crosstalk of these two repair pathways in cancer, we analysed human gastric adenocarcinoma AGS cells over-expressing Polß or Polß active site mutants, alone or in combination with MLH1 silencing. Next, we investigated the cellular response to the alkylating agent methyl methanesulfonate (MMS) and the purine analogue 6-thioguanine (6-TG), agents that induce lesions that are substrates for BER and/or MMR. AGS cells over-expressing Polß were resistant to 6-TG to a similar extent as when MLH1 was inactivated while inhibition of O6-methylguanine-DNA methyltransferase (MGMT) was required to detect resistance to MMS. Upon either treatment, the association with MLH1 down-regulation further amplified the resistant phenotype. Moreover, AGS cells mutated in Polß were hypersensitive to both 6-TG and MMS killing and their sensitivity was partially rescued by MLH1 silencing. We provide evidence that the critical lethal lesions in this new pathway are double strand breaks that are exacerbated when Polß is defective and relieved when MLH1 is silenced. In conclusion, we provide evidence of crosstalk between MLH1 and Polß that modulates the response to alkylation damage. These studies suggest that the Polß/MLH1 status should be taken into consideration when designing chemotherapeutic approaches for gastric cancer.
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A panel of vectors was constructed to encode carcinoembryonic antigen (CEA) fused at its C-terminal end to various polypeptides, so as to compare their immunogenicity by plasmid DNA immunization and adenovirus injection in wild-type and CEA transgenic (CEA.tg) mice. Fusions between CEA and the minimized domain of tetanus toxin fragment C (CEA-DOM) or the Fc portion of IgG1 (CEA-FcIgG) were identified as highly immunogenic and elicited significant CEA-specific antibody and CD8+ T cell responses. CEA.tg mice were protected from tumor growth on challenge with MC38-CEA tumor cells only when immunized with repeated injections of plasmid pV1J/CEA-DOM followed by Ad/CEA-DOM. Depletion of T-regulatory cells resulted in an increased immune response and antitumor effect with DNA plus adenovirus immunization. In addition, this protective effect was abrogated if the NK, CD4+, or CD8+ cell population from immunized mice was depleted before tumor challenge. Passive transfer studies demonstrated that CD4+ and CD8+ T cells and antibodies contributed to the antitumor effect, thus suggesting that a genetic vaccine based on the use of plasmid DNA and adenoviral vectors encoding CEA fused to immunoenhancing sequences augments CEA-specific immune responses and effectively protects from tumor development.