The Ins and Outs of Messenger RNA Electroporation for Physical Gene Delivery in Immune Cell-Based Therapy

Messenger RNA (mRNA) electroporation is a powerful tool for transient genetic modification of cells. This non-viral method of genetic engineering has been widely used in immunotherapy. Electroporation allows fine-tuning of transfection protocols for each cell type as well as introduction of multiple protein-coding mRNAs at once. As a pioneering group in mRNA electroporation, in this review, we provide an expert overview of the ins and outs of mRNA electroporation, discussing the different parameters involved in mRNA electroporation as well as the production of research-grade and production and application of clinical-grade mRNA for gene transfer in the context of cell-based immunotherapies.

Dendritic cells as cancer therapeutics

The ability of immune therapies to control cancer has recently generated intense interest. This therapeutic outcome is reliant on T cell recognition of tumour cells. The natural function of dendritic cells (DC) is to generate adaptive responses, by presenting antigen to T cells, hence they are a logical target to generate specific anti-tumour immunity. Our understanding of the biology of DC is expanding, and they are now known to be a family of related subsets with variable features and function. Most clinical experience to date with DC vaccination has been using monocyte-derived DC vaccines. There is now growing experience with alternative blood-derived DC derived vaccines, as well as with multiple forms of tumour antigen and its loading, a wide range of adjuvants and different modes of vaccine delivery. Key insights from pre-clinical studies, and lessons learned from early clinical testing drive progress towards improved vaccines. The potential to fortify responses with other modalities of immunotherapy makes clinically effective "second generation" DC vaccination strategies a priority for cancer immune therapists.

Trial Watch: Therapeutic vaccines in metastatic renal cell carcinoma

Despite the renaissance of cancer immunotherapy, no novel immunotherapy has been approved for the treatment of renal cell cancer (RCC) since the availability of recombinant cytokines (interleukin-2, interferon-α). All vaccine trials have failed to meet their endpoints although they have highlighted potential predictive biomarkers (e.g., pre-existing immune response, hematological parameters, tumor burden). Recent advances in immunomodulatory therapies have prompted the study of combination treatments targeting the tumor immunosuppressive microenvironment consisting of regulatory T-cells (Treg), myeloid suppressor cells, and cytokines. Approaches under investigation are use of inhibitors to curb the overexpression of immune checkpoint ligands by tumor cells (e.g., anti-CTLA-4, anti-PD-1/PD-L1) and exploiting the immunomodulatory effects of anti-angiogenic agents that are the current standard of metastatic RCC care. Phase III trials are focusing on the possible synergy between therapeutic vaccines (e.g., IMA-901 and AGS-003) and anti-angiogenic agents.

Adjuvant therapy for renal cell carcinoma: past, present, and future

At the present time, the standard of care for patients who have received nephrectomy for localized renal cell carcinoma (RCC) is radiographic surveillance. With a number of novel targeted agents showing activity in the setting of metastatic RCC, there has been great interest in exploring the potential of the same agents in the adjuvant setting. Herein, we discuss the evolution of adjuvant trials in RCC, spanning from the immunotherapy era to the targeted therapy era. Pitfalls of current studies are addressed to provide a context for interpreting forthcoming results. Finally, we outline avenues to incorporate promising investigational agents, such as PD-1 (programmed death-1) inhibitors and MNNG transforming gene inhibitors, in future adjuvant trials.

Immune therapy for kidney cancer: a second dawn?

Agents targeting the immune system have been a historical standard of care in metastatic renal cell carcinoma (RCC), but have largely been supplanted by newer targeted therapy. Recent insights into the regulation of an anti-tumor immune response has led to the development of agents that can activate immune responses primarily within the tumor, enabling the possibility of achieving durable tumor response in the absence of significant systemic toxicity. In addition, a better understanding of tumor immunology has raised the potential of developing predictive biomarkers of response to immunotherapy. Novel approaches including inhibition of immune checkpoints has entered clinical testing in RCC.

Immunological heterogeneity of the RCC microenvironment: do targeted therapies influence immune response?

The introduction of targeted agents has substantially improved treatment of metastatic clear-cell renal cell carcinoma (RCC). However, complete responses are rare and therapy is not curative. Moreover, information on the latest generation of potent and selective vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKI) suggests that a plateau has been reached in terms of efficacy. Recent data reveal that targeted agents are involved in modulating immune responses in RCC. In addition, current research adds to our understanding of how RCC escapes an effective anti-tumor response with the potential to modulate these processes by drug development. This review provides specific insight into targeted therapy induced changes in the immunological microenvironment of RCC, summarizes the available evidence, and discusses potential therapeutic implications.

Immunotherapy for renal cell carcinoma

Although several cytokines have shown antitumor activity in renal cell carcinoma (RCC), the most consistent results have been reported with interleukin-2 (IL-2) and interferon (IFN). Recent insights into how the immune response to a tumor is regulated hold the promise of allowing patients to obtain a durable response to immunotherapy, perhaps without the significant toxicity associated with conventional approaches. This review describes how improvements in patient selection, combination therapy, and investigational agents might expand and better define the role of immunotherapy in metastatic RCC.