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.

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.

Multitasking nanoparticles are gaining great attention for smart drug delivery systems. The exploration of the nano-scale opens new concrete opportunities for revealing new properties and undiscovered cell-particle interactions. Here we present a biodegradable nanoporous silicon nanoparticle that can be successfully employed for in vivo targeted drug delivery and sustained release. The bare nanoporous nanocarriers can be accurately designed and fabricated with an effective control of porosity, surface chemistry and particle size, up to a few nm. The proposed nanoparticles exhibit several remarkable features including high payload, biodegradability, no toxicity, and multiple loading in water without the need of additional chemical reagents at room temperature. The targeting strategy is based on phage display technology that was successfully used to discover cell surface binding peptide for murine B lymphoma A20 cell line. The peptide used in combination with the nanoporous nanoparticles allows an efficient in vivo targeting, a sustained release and a sensible therapeutic effect.

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.

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