DARPins: Promising Scaffolds for Theranostics.

O N Shilova,S M Deyev

doi:10.32607/20758251-2019-11-4-42-53

O N Shilova, S M Deyev

Open Access

https://doi.org/10.32607/20758251-2019-11-4-42-53

Copy DOI

Abstract

Monoclonal antibodies are the classical basis for targeted therapy, but the development of alternative binding proteins has made it possible to use non-immunoglobulin proteins as targeting modules. The advantages of DARPins, scaffold proteins based on ankyrin repeats, over antibodies are as follows: small size, stability over a wide range of temperatures and pH values, low aggregation tendency, and ease of production in heterologous expression systems. The differences in the structure of the paratope of DARPin and antibodies broaden the spectrum of target molecules, while the ease of creating hybrid fusion proteins allows one to obtain bispecific and multivalent constructs. In this article, we summarize recent data on the development of therapeutic and imaging compounds based on DARPins.

Highlights

The hybridoma technology described by Kohler and Milstein in 1975 [1] has enabled the production of monoclonal antibodies, which are used in research and diagnostics, as well as in therapy
This paper focuses on DARPins, which are artificial proteins that are based on ankyrin repeats
The lymphocytes are transduced with constructs that encode the chimeric antigen receptor (CAR), which is specific to the tumor antigen and has all the domains necessary for cell activation, including the signal sequences of the co-stimulating molecules of the natural receptor [95]

Summary

INTRODUCTION

The hybridoma technology described by Kohler and Milstein in 1975 [1] has enabled the production of monoclonal antibodies, which are used in research and diagnostics, as well as in therapy. Designing alternative scaffolds involves two stages: (1) the design of a library of protein variants by random site-specific mutagenesis and (2) selection of molecules using phage, ribosome, or yeast display, linking genotype (a protein gene sequence) and phenotype (its ability to bind to the target) The advantages of these alternative binding proteins include their small size, which facilitates tumor penetration; the absence of Fc-avoiding antibody-mediated cytotoxicity and complement-mediated cytotoxicity; in many cases, high thermostability that enables longterm storage of a preparation at room temperature without loss of activity; ease of production in bacteria, and even the possibility of performing direct chemical synthesis. Monomeric DARPins can act as binding modules for high-affinity radio immunodiagnostics, in which proteins conjugated to a radionuclide carrier (typically a chelator or quasicovalent technetium complexes) are used [44] This technology was originally developed for single-chain antibodies, but soon it was applied to other scaffold proteins, since the basic requirements for binding modules for radioimmune diagnostics include high affinity and small size [45, 46].

Apoptosis induction

Findings

CONCLUSIONS