A first-in-human trial on the safety and immunogenicity of COVID-eVax, a cellular response-skewed DNA vaccine against COVID-19.

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.

COVID-eVax, an electroporated DNA vaccine candidate encoding the SARS-CoV-2 RBD, elicits protective responses in animal models.

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.

SARS-CoV-2 SPIKE PROTEIN: an optimal immunological target for vaccines.

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.

New classes of potent heparanase inhibitors from ligand-based virtual screening.

Heparanase is a validated target in cancer therapy and a potential target for several inflammatory pathologies. A ligand-based virtual screening of commercial libraries was performed to expand the chemical space of small-molecule inhibitors. The screening was based on similarity with known inhibitors and was performed in several runs, starting from literature compounds and progressing through newly discovered inhibitors. Among the fifty-five tested compounds, nineteen had IC50 values lower than 5 µM and some showed remarkable potencies. Importantly, tere- and isophthalamides derivatives belong to new structural classes of heparanase inhibitors and some of them showed enzyme affinities (61 and 63, IC50 = 0.32 and 0.12 µM, respectively) similar to those of the most potent small-molecule inhibitors reported so far. Docking studies provided a comprehensive binding hypothesis shared by compounds with significant structural diversity. The most potent inhibitors reduced cell invasiveness and inhibited the expression of proangiogenic factors in tumour cell lines.

MicroRNA-128-3p-mediated depletion of Drosha promotes lung cancer cell migration.

Alteration in microRNAs (miRNAs) expression is a frequent finding in human cancers. In particular, widespread miRNAs down-regulation is a hallmark of malignant transformation. In the present report, we showed that the miR-128-3p, which is up-regulated in lung cancer tissues, has Drosha and Dicer, two key enzymes of miRNAs processing, as the main modulation targets leading to the widespread down-regulation of miRNA expression. We observed that the miRNAs downregulation induced by miR-128-3p contributed to the tumorigenic properties of lung cancer cells. In particular, miR-128-3p-mediated miRNAs down-regulation contributed to aberrant SNAIL and ZEB1 expression thereby promoting the epithelial-to-mesenchymal transition (EMT) program. Drosha also resulted to be implicated in the control of migratory phenotype as its expression counteracted miR-128-3p functional effects. Our study provides mechanistic insights into the function of miR-128-3p as a key regulator of the malignant phenotype of lung cancer cells. This also enforces the remarkable impact of Drosha and Dicer alteration in cancer, and in particular it highlights a role for Drosha in non-small-cell lung cancer cells migration.

Kinetic analysis and molecular modeling of the inhibition mechanism of roneparstat (SST0001) on human heparanase.

Heparanase is a ß-d-glucuronidase which cleaves heparan sulfate chains in the extracellular matrix and on cellular membranes. A dysregulated heparanase activity is intimately associated with cell invasion, tumor metastasis and angiogenesis, making heparanase an attractive target for the development of anticancer therapies. SST0001 (roneparstat; Sigma-Tau Research Switzerland S.A.) is a non-anticoagulant 100% N-acetylated and glycol-split heparin acting as a potent heparanase inhibitor, currently in phase I in advanced multiple myeloma. Herein, the kinetics of heparanase inhibition by roneparstat is reported. The analysis of dose-inhibition curves confirmed the high potency of roneparstat (IC50 ≈ 3 nM) and showed, at higher concentrations, a Hill coefficient consistent with the engagement of two molecules of inhibitor. A homology model of human heparanase GS3 construct was built and used for docking experiments with inhibitor fragments. The model has high structural similarity with the recently reported crystal structure of human heparanase. Different interaction schemes are proposed, which support the hypothesis of a complex binding mechanism involving the recruitment of one or multiple roneparstat chains, depending on its concentration. In particular, docking solutions were obtained in which (i) a single roneparstat molecule interacts with both heparin-binding domains (HBDs) of heparanase or (ii) two fragments of roneparstat interact with either HBD-1 or HBD-2, consistent with the possibility of different inhibitor:enzyme binding stoichiometries. This study provides unique insights into the mode of action of roneparstat as well as clues of its interaction with heparanase at a molecular level, which could be exploited to design novel potential inhibitor molecules.

Human lung adenocarcinoma cell cultures derived from malignant pleural effusions as model system to predict patients chemosensitivity.

BACKGROUND: Lung cancer is the leading cause of cancer related deaths and Malignant Pleural Effusion (MPE) is a frequent complication. Current therapies suffer from lack of efficacy in a great percentage of cases, especially when cancer is diagnosed at a late stage. Moreover patients' responses vary and the outcome is unpredictable. Therefore, the identification of patients who will benefit most of chemotherapy treatment is important for accurate prognostication and better outcome. In this study, using malignant pleural effusions (MPE) from non-small cell lung cancer (NSCLC) patients, we established a collection of patient-derived Adenocarcinoma cultures which were characterized for their sensitivity to chemotherapeutic drugs used in the clinical practice. METHODS: Tumor cells present in MPEs of patients with NSCLC were isolated by density gradient centrifugation, placed in culture and genotyped by next generation sequencing. In a subset of cases patient derived xenografts (PDX) were obtained upon tumor cell inoculation in rag2/IL2 knock-out mice. Isolated primary cultures were characterized and tested for drug sensitivity by in vitro proliferation assays. Additivity, antagonism or synergy for combinatorial treatments were determined by analysis with the Calcusyn software. RESULTS: We have optimized isolation procedures and culture conditions to expand in vitro primary cultures from Malignant Pleural Effusions (MPEs) of patients affected by lung adenocarcinomas, the most frequent form of non small cell lung cancer. Using this approach we have been able to establish 16 primary cultures from MPEs. Cells were banked at low passages and were characterized for their mutational pattern by next generation sequencing for most common driver mutations in lung cancer. Moreover, amplified cultures were shown to engraft with high efficiency when injected in immunocompromised mice. Cancer cell sensitivity to drugs used in standard chemotherapy regimens was assessed either individually or in combination. Differential chemosensitivity and different mutation profiles were observed which suggests that this isolation method could provide a platform for predicting the efficacy of chemotherapy in the clinical setting. Most importantly for six patients it was possible to establish a correlation between drug response in vitro and response to therapy in the clinic. CONCLUSIONS: Results obtained using primary cultured cells from MPEs underscore the heterogeneity of NSCLC in advanced stage as indicated by drug response and mutation profile. Comparison of data obtained from in vitro assays with patients' responses to therapy leads to the conclusion that this strategy may provide a potentially useful approach for evaluating individual chemosensitivity profile and tailor the therapy accordingly. Furthermore, combining MPE-derived primary cultures with their genomic testing allows to identify patients eligible to trials with novel targeted agents.

Circulating MMP11 and specific antibody immune response in breast and prostate cancer patients.

BACKGROUND: Tumor Associated Antigens are characterized by spontaneous immune response in cancer patients as a consequence of overexpression and epitope-presentation on MHC class I/II machinery. Matrix Metalloprotease 11 (MMP11) expression has been associated with poor prognosis for several cancer types, including breast and prostate cancer. METHODS: MMP11 expression was determined by immunoistochemistry in breast and prostate cancer samples. Circulating MMP11 protein as well as the spontaneous immune responses against MMP11 were analyzed in a set of breast and prostate cancer patients. RESULTS: In plasma samples MMP11 protein was present in 5/13 breast cancer patients and in 1/12 prostate cancer patients. An antibody response was observed in 7/13 breast cancer patients and in 3/12 prostate cancer patients. CONCLUSIONS: These findings further suggest MMP11 as a promising biomarker for these tumor types and a suitable target for cancer immunotherapy strategies.

Kinetic Detection of Apoptosis Events Via Caspase 3/7 Activation in a Tumor-Immune Microenvironment on a Chip.

The development of advanced biological models like microphysiological systems, able to rebuild the complexity of the physiological and/or pathological environments at a single-cell detail level in an in-vivo-like approach, is proving to be a promising tool to understand the mechanisms of interactions between different cell populations and main features of several diseases. In this frame, the tumor-immune microenvironment on a chip represents a powerful tool to profile key aspects of cancer progression, immune activation, and response to therapy in several immuno-oncology applications. In the present chapter, we provide a protocol to identify and characterize the time evolution of apoptosis by time-lapse fluorescence and confocal imaging in a 3D microfluidic coculture murine model including cancer and spleen cells.

Isolation and Characterization of Neutralizing Monoclonal Antibodies from a Large Panel of Murine Antibodies against RBD of the SARS-CoV-2 Spike Protein.

The COVID-19 pandemic, once a global crisis, is now largely under control, a testament to the extraordinary global efforts involving vaccination and public health measures. However, the relentless evolution of SARS-CoV-2, leading to the emergence of new variants, continues to underscore the importance of remaining vigilant and adaptable. Monoclonal antibodies (mAbs) have stood out as a powerful and immediate therapeutic response to COVID-19. Despite the success of mAbs, the evolution of SARS-CoV-2 continues to pose challenges and the available antibodies are no longer effective. New variants require the ongoing development of effective antibodies. In the present study, we describe the generation and characterization of neutralizing mAbs against the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein by combining plasmid DNA and recombinant protein vaccination. By integrating genetic immunization for rapid antibody production and the potent immune stimulation enabled by protein vaccination, we produced a rich pool of antibodies, each with unique binding and neutralizing specificities, tested with the ELISA, BLI and FACS assays and the pseudovirus assay, respectively. Here, we present a panel of mAbs effective against the SARS-CoV-2 variants up to Omicron BA.1 and BA.5, with the flexibility to target emerging variants. This approach ensures the preparedness principle is in place to address SARS-CoV-2 actual and future infections.

EMT markers in lung adenocarcinoma pleural effusion spheroid cells.

Epithelial-to-mesenchymal transition (EMT) is a process in which cells undergo a developmental switch from epithelial to mesenchymal phenotype. This process has been related to embryologic morphogenesis but also to cancer progression and metastasis. The aim of the current study was to investigate the expression of EMT-related markers in adherent and spheroid cell cultures derived from malignant pleural effusions (MPEs) of patients affected by lung adenocarcinoma. On the basis of efficient in vitro propagation, six cases of MPEs were selected and analyzed by immunocytochemistry staining for EMT markers and by RT-PCR for transcription factors known to orchestrate EMT. EMT markers immunostaining showed in spheroids a statistically significant correlation between the loss of E-cadherin immunoreactivity and overexpression of N-cadherin (P < 0.001). Likewise loss of EpCAM epithelial marker was coincident with Vimentin overexpression (P < 0.001). RT-PCR analysis of transcription factors Snail, Slug, and Twist showed a highly variable expression, although a general trend to increase was observed. Importantly, in some selected cases it was possible to establish a precise relationship between spheroid formation, EMT switch and increased upregulation of the marker related to cancer stemness such as ALDH positivity. Therefore, MPE-derived cell cultures, while recapitulating the heterogeneity of lung cancer, are a suitable system to study the mechanisms at the basis of EMT and to understand its relationship with the generation of cancer stem cells.

Carnitines slow down tumor development of colon cancer in the DMH-chemical carcinogenesis mouse model.

Dietary agents are receiving much attention for the chemoprevention of cancer. While curcumin is known to influence several pathways and affect tumor growth in vivo, carnitin and its congeners play a variety of important metabolic functions: are involved in the oxydation of long-chain fatty acids, regulate acyl-CoA levels and influence protein activity and stability by modifying the extent of protein acetylation. In this study we evaluated the efficacy of carnitines in the prevention of cancer development using the 1,2,-dimethylhydrazine (DMH)-induced colon carcinogenesis model. We also assessed whether their combination was able to give rise to increased protection from cancer development. Mice treated with DMH were dosed orally with curcumin and/or carnitine and acylcarnitines for 20 weeks. At the end of the treatment colon samples were collected, and scored for multiple ACF and adenomas. We observed that carnitine and acyl-carnitines had same, if not higher, efficacy than curcumin alone in inhibiting the formation of neoplastic lesions induced by DMH treatment. Interestingly, the combination of curcumin and acetyl-L-carnitine was able to fully inhibit the development of advanced adenoma lesions. Our data unveil the antitumor effects of carnitines and warrant additional studies to further support the adoption of carnitines as cancer chemopreventative agents.

A linear DNA encoding the SARS-CoV-2 receptor binding domain elicits potent immune response and neutralizing antibodies in domestic cats.

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.

Immunogenicity of COVID-eVax Delivered by Electroporation Is Moderately Impacted by Temperature and Molecular Isoforms.

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.

Novel anti-ErbB3 monoclonal antibodies show therapeutic efficacy in xenografted and spontaneous mouse tumors.

The role of the ErbB3 receptor in signal transduction is to augment the signaling repertoire of active heterodimeric ErbB receptor complexes through activating the PI3K/AKT pathway, which in turn promotes survival and proliferation. ErbB3 has recently been proposed to be involved in acquired resistance to tyrosine kinase inhibitors (TKIs), and is therefore a promising new drug cancer target. Since ErbB3 is a kinase defective receptor, it cannot be targeted by small molecule inhibitors, whereas monoclonal antibodies may offer a viable strategy for pharmacological intervention. In this study, we have utilized DNA electroporation (DNA-EP) to generate a set of novel hybridomas directed against human ErbB3, which have been characterized for their biochemical and functional properties and selected for their ability to negatively regulate the ErbB3-mediated signaling pathway. In vitro, the anti-ErbB3 antibodies modulate the growth rate of cancer cells of different origins. In vivo they show antitumoral properties in a xenograft model of human pancreatic tumor and in the ErbB2-driven carcinogenesis genetically engineered mouse model (GEMM) for mammary tumor, the BALB/neuT. Our data confirm that downregulating the ErbB3-mediated signals with the use of anti-ErbB3 monoclonal antibodies is both feasible and relevant for therapeutic purposes and provides new opportunities for novel anti-ErbB3 combinatory strategies for cancer treatment.

Persistent B cell memory after SARS-CoV-2 vaccination is functional during breakthrough infections.

Breakthrough SARS-CoV-2 infections in fully vaccinated individuals are considered a consequence of waning immunity. Serum antibodies represent the most measurable outcome of vaccine-induced B cell memory. When antibodies decline, memory B cells are expected to persist and perform their function, preventing clinical disease. We investigated whether BNT162b2 mRNA vaccine induces durable and functional B cell memory in vivo against SARS-CoV-2 3, 6, and 9 months after the second dose in a cohort of health care workers (HCWs). While we observed physiological decline of SARS-CoV-2-specific antibodies, memory B cells persist and increase until 9 months after immunization. HCWs with breakthrough infections had no signs of waning immunity. In 3-4 days, memory B cells responded to SARS-CoV-2 infection by producing high levels of specific antibodies in the serum and anti-Spike IgA in the saliva. Antibodies to the viral nucleoprotein were produced with the slow kinetics typical of the response to a novel antigen.

Genetic Vaccination as a Flexible Tool to Overcome the Immunological Complexity of Invasive Fungal Infections.

The COVID-19 pandemic has highlighted genetic vaccination as a powerful and cost-effective tool to counteract infectious diseases. Invasive fungal infections (IFI) remain a major challenge among immune compromised patients, particularly those undergoing allogeneic hematopoietic bone marrow transplantation (HSCT) or solid organ transplant (SOT) both presenting high morbidity and mortality rates. Candidiasis and Aspergillosis are the major fungal infections among these patients and the failure of current antifungal therapies call for new therapeutic aids. Vaccination represents a valid alternative, and proof of concept of the efficacy of this approach has been provided at clinical level. This review will analyze current understanding of antifungal immunology, with a particular focus on genetic vaccination as a suitable strategy to counteract these diseases.

The Nuts and Bolts of SARS-CoV-2 Spike Receptor-Binding Domain Heterologous Expression.

COVID-19 is a highly infectious disease caused by a newly emerged coronavirus (SARS-CoV-2) that has rapidly progressed into a pandemic. This unprecedent emergency has stressed the significance of developing effective therapeutics to fight the current and future outbreaks. The receptor-binding domain (RBD) of the SARS-CoV-2 surface Spike protein is the main target for vaccines and represents a helpful "tool" to produce neutralizing antibodies or diagnostic kits. In this work, we provide a detailed characterization of the native RBD produced in three major model systems: Escherichia coli, insect and HEK-293 cells. Circular dichroism, gel filtration chromatography and thermal denaturation experiments indicated that recombinant SARS-CoV-2 RBD proteins are stable and correctly folded. In addition, their functionality and receptor-binding ability were further evaluated through ELISA, flow cytometry assays and bio-layer interferometry.

A new humanized antibody is effective against pathogenic fungi in vitro.

Invasive fungal infections mainly affect patients undergoing transplantation, surgery, neoplastic disease, immunocompromised subjects and premature infants, and cause over 1.5 million deaths every year. The most common fungi isolated in invasive diseases are Candida spp., Cryptococcus spp., and Aspergillus spp. and even if four classes of antifungals are available (Azoles, Echinocandins, Polyenes and Pyrimidine analogues), the side effects of drugs and fungal acquired and innate resistance represent the major hurdles to be overcome. Monoclonal antibodies are powerful tools currently used as diagnostic and therapeutic agents in different clinical contexts but not yet developed for the treatment of invasive fungal infections. In this paper we report the development of the first humanized monoclonal antibody specific for ß-1,3 glucans, a vital component of several pathogenic fungi. H5K1 has been tested on C. auris, one of the most urgent threats and resulted efficient both alone and in combination with Caspofungin and Amphotericin B showing an enhancement effect. Our results support further preclinical and clinical developments for the use of H5K1 in the treatment of patients in need.