Orchestrating a Symphony on a Single Conjugate: Aptamer Targeting, Gene Silencing, and Immunomodulation to Enhance Antitumor Response

Artificial Dendritic Cells: A New Era of Promising Antitumor Immunotherapy

The accelerated development of antitumor immunotherapies in recent years has brought immunomodulation into the spotlight. These include immunotherapeutic treatments with dendritic cell (DC)-based vaccines which can elicit tumor-specific immune responses and prolong survival. However, this personalized treatment has several drawbacks, including being costly, labor-intensive, and time consuming. This has sparked interest in producing artificial dendritic cells (aDCs) to open up the possibility of standardized "off-the-shelf" protocols and circumvent the cumbersome and expensive personalized medicine. aDCs take advantage of materials that can be designed and tailored for specific clinical applications. Here, an overview of the immunobiology underlying antigen presentation by DCs is provided in an attempt to select the key features to be mimicked and/or improved through the development of aDCs. The inherent properties of aDCs that greatly impact their performance in vivo and, consequently, the fate of the triggered immune response are also outlined.

Targeted delivery of RNAi to cancer cells using RNA-ligand displaying exosome

Exosome is an excellent vesicle for in vivo delivery of therapeutics, including RNAi and chemical drugs. The extremely high efficiency in cancer regression can partly be attributed to its fusion mechanism in delivering therapeutics to cytosol without endosome trapping. However, being composed of a lipid-bilayer membrane without specific recognition capacity for aimed-cells, the entry into nonspecific cells can lead to potential side-effects and toxicity. Applying engineering approaches for targeting-capacity to deliver therapeutics to specific cells is desirable. Techniques with chemical modification in vitro and genetic engineering in cells have been reported to decorate exosomes with targeting ligands. RNA nanoparticles have been used to harbor tumor-specific ligands displayed on exosome surface. The negative charge reduces nonspecific binding to vital cells with negatively charged lipid-membrane due to the electrostatic repulsion, thus lowering the side-effect and toxicity. In this review, we focus on the uniqueness of RNA nanoparticles for exosome surface display of chemical ligands, small peptides or RNA aptamers, for specific cancer targeting to deliver anticancer therapeutics, highlighting recent advances in targeted delivery of siRNA and miRNA that overcomes the previous RNAi delivery roadblocks. Proper understanding of exosome engineering with RNA nanotechnology promises efficient therapies for a wide range of cancer subtypes.

Type II CRISPR/Cas9 approach in the oncological therapy

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a prokaryotic adaptable immune mechanism used by many bacteria and archaea to protect themselves from foreign nucleic acids. This complex system can recognize and cut non-self DNA in order to provide the prokaryotic organisms a strong defense against foreign viral or plasmid attacks and make the cell immune from further assaults. Today, it has been adapted to be used in vitro and in vivo in eukaryotic cells to perform a complete and highly selective gene knockout or a specific gene editing. The ease of use and the low cost are only two features that have made it very popular among the scientific community and the possibility to be used as a clinical treatment in several genetic derived pathologies has rapidly spread its fame worldwide. However, CRISPR is still not fully understood and many efforts need to be done in order to make it a real power tool for the human clinical treatment especially for oncological patients. Indeed, since cancer originates from non-lethal genetic disorders, CRISPR discovery fuels the hope to strike tumors on their roots. More than 4000 papers regarding CRISPR were published in the last ten years and only few of them take in count the possible applications in oncology. The purpose of this review is to clarify many problematics on the CRISPR usage and highlight its potential in oncological therapy.

Current Progress in Non-viral RNAi-Based Delivery Strategies to Lymphocytes

RNAi-based therapy holds great promise, as it can be utilized for the treatment of multiple conditions in an accurate manner via sequence-specific manipulation of gene expression. To date, RNAi therapeutics have advanced into clinical trials for liver diseases and solid tumors; however, delivery of RNAi to leukocytes in general and to lymphocytes in particular remains a challenge. Lymphocytes are notoriously hard to transduce with RNAi payloads and are disseminated throughout the body, often located in deep tissues; therefore, developing an efficient systemic delivery system directed to lymphocytes is not a trivial task. Successful manipulation of lymphocyte function with RNAi possesses immense therapeutic potential, as it will enable researchers to resolve lymphocyte-implicated diseases such as inflammation, autoimmunity, transplant rejection, viral infections, and blood cancers. This potential has propelled the development of novel targeted delivery systems relying on the accumulating research knowledge from multiple disciplines, including materials science and engineering, immunology, and genetics. Here, we will discuss the recent progress in non-viral delivery strategies of RNAi payloads to lymphocytes. Special emphasis will be made on the challenges and potential opportunities in manipulating lymphocyte function with RNAi. These approaches might ultimately become a novel therapeutic modality to treat leukocyte-related diseases.