Ex vivo manipulation of primary cells is critical to the success of cell-based therapies, however, limitations of existing ex vivo delivery approaches may dramatically restrict the use of cell engineering to treat disease.
We used a genome-wide approach to study optimized electroporation treatment and microfluidic cell squeezing to identify the impact of delivery technique on gene expression profiles in human T cells. To validate the microarray results, we used a multiplex cytokine analysis comprised of 42 key T cell cytokines to assess perturbation of cytokine secretion. Finally, in a direct comparison of therapeutic functionality, the efficacy of T cells edited for PD-1 via electroporation and cell squeezing was assessed using therapeutic treatment of the Eg.7 OVA tumor model.
We identified striking disruptions in transcript expression after treatment with electroporation (17% of genes mis-regulated, FDR q < 0.1), whereas cells treated with microfluidic squeezing had similar expression profiles to untreated control cells (0% of genes mis-regulated, FDR q < 0.1). These genetic disruptions result in concomitant perturbation of cytokine secretion including a 648-fold increase in IL-2 secretion (p < 0.01) and a 30-fold increase in IFNγ secretion (p < 0.05) in electroporated cells. Squeezing cells did not result in the non-specific secretion of any of the 42 cytokines tested. Ultimately, the effects at the transcript and protein level resulted in functional deficiencies in vivo with electroporated T cells failing to demonstrate sustained antigen-specific effector responses and tumor control.
This work demonstrates that the delivery mechanism used to insert biomolecules affects functionality and warrants further study. The significant differences in outcomes from the two techniques underscores the importance of understanding the impact of intracellular delivery methods on cell function for research and clinical applications. Hence, for both research and therapeutic applications, the functional and safety consequences of the selected intracellular delivery technique and its impact on cell phenotype should be carefully evaluated.
Clinical trial identification
Legal entity responsible for the study
J. Hanson, J. Cole, L. Cassereau, J. Bugge, T. Ditommaso, J. Gilbert, H. Bernstein, A. Sharei: Employed by SQZ Biotech.