Physical transfection technologies for macrophages and dendritic cells in immunotherapy

ABSTRACT

Introduction

Dendritic cells (DCs) and macrophages, two important antigen presenting cells (APCs) of the innate immune system, are being explored for the use in cell-based cancer immunotherapy. For this application, the therapeutic potential of patient-derived APCs is increased by delivering different types of functional macromolecules, such as mRNA and pDNA, into their cytosol. Compared to the use of viral and non-viral delivery vectors, physical intracellular delivery techniques are known to be more straightforward, more controllable, faster and generate high delivery efficiencies.

Areas covered

This review starts with electroporation as the most traditional physical transfection method, before continuing with the more recent technologies such as sonoporation, nanowires and microfluidic cell squeezing. A description is provided of each of those intracellular delivery technologies with their strengths and weaknesses, especially paying attention to delivery efficiency and safety profile.

Expert opinion

Given the common use of electroporation for the production of therapeutic APCs, it is recommended that more detailed studies are performed on the effect of electroporation on APC fitness, even down to the genetic level. Newer intracellular delivery technologies seem to have less impact on APC functionality but further work is needed to fully uncover their suitability to transfect APCs with different types of macromolecules.

KEYWORDS:

• Cancer immunotherapy
• innate immunity
• dendritic cells
• macrophages
• cell engineering
• transfection
• electroporation
• sonoporation
• nanowires
• microfluidic cell squeezing
• pDNA
• mRNA
• antigens

Article highlights

• Electroporation is able to achieve high delivery efficiency in patient-derived antigen presenting cells for different kinds of macromolecules, but recent reports point to unwanted effects on cell homeostasis and cellular functionality, including altered surface receptor expression, cytokine secretion and reduced migration capacity.

• Sonoporation is able to deliver macromolecules in APCs but less efficient compared to as electroporation. However, impairment of the expression of co-stimulatory molecules is seen and the technique can be associated with a high toxicity.

• NanoWires achieve a high delivery efficiency and viability, even though there is still doubt on the underlying mechanism. Successful intracellular delivery of large nucleic acids remains to be confirmed. Nevertheless, NanoWires do not influence the immune response or the expression of several immune response genes.

• Cell squeezing is an upcoming microfluidics based technique that is promising due to its efficacy, speed and simplicity. Novel technical variations on this concept seem to resolve shortcomings of the early designs and seems very promising for in the high-throughput production of therapeutic APCs.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was funded by the funding by the special research fund (BOF: number 01IO1214) of Ghent University, the financial support of FWO (3G0B2814N and 3G006714) and VLAIO (IWT SBO 140061). The funding by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant No. 648124) is acknowledged with gratitude.