Electrochemotherapy impacts the viability, functionality and phenotype of murine dendritic cells in voltage-dependent manner

Dendritic cells (DCs) are central to the initiation of anti-tumour immunity, yet the direct effects of electrochemotherapy (ECT) on DC biology remain poorly defined. We investigated how varying electric field strengths (800, 1000, and 1300 V/cm) modulate murine DC viability, phenotype, Toll-like receptor (TLR) expression and functional responses in vitro. ECT induced predominantly necrotic cell death in a voltage-dependent manner, with higher voltages markedly reducing viability. Despite this decline, surviving DCs exposed to 1000 V/cm and 1300 V/cm upregulated MHC II and CD80, indicating activation of the remaining population. ECT also altered TLR expression, significantly increasing TLR6 and TLR9 while reducing TLR4, TLR7 and TLR8 levels. Functionally, ECT impaired DC cytokine responses to TLR4 and TLR7/8 stimulation but preserved or enhanced responsiveness to the TLR9 agonist CpG, suggesting selective disruption of downstream TLR pathways. Together, these findings demonstrate that ECT differentially shapes DC survival and function depending on electric field intensity, with low-voltage ECT better preserving DC competence and higher voltages inducing activation but impairing responsiveness. These data highlight opportunities to optimise ECT protocols and rationally combine ECT with immune adjuvants to enhance therapeutic immunogenicity.