Electro-antibacterial therapy (EAT) to enhance intracellular bacteria clearance in pancreatic cancer cells

Abstract

Intratumoral bacteria have been implicated in driving tumor progression, yet effective treatments to modulate the tumor microbiome remain limited. In this study, we investigate the use of electroporation in combination with metronidazole to enhance the clearance of intracellular Fusobacterium nucleatum within pancreatic cancer cells. We explore various parameters, including electric field strength, pulse width, and pulse number to assess the permeability of pancreatic cancer cells infected with F. nucleatum, compared to non-infected cells of the same type. We subsequently quantify the clearance of intracellular bacteria when these pulsing schemes are applied to a suspension of infected pancreatic cancer cells in the presence of metronidazole. Our results reveal distinct differences in cell permeability between infected and non-infected cells, identifying a unique biophysical marker for host cells infected with F. nucleatum. We demonstrate that the combinatorial use of electroporation and metronidazole significantly enhances the delivery of metronidazole into host cells, leading to more effective clearance of intracellular F. nucleatum compared to independent treatments; we term this novel approach Electro-Antibacterial Therapy (EAT). EAT holds promise as an innovative strategy for addressing intratumoral bacteria in pancreatic cancer, other malignancies, and potentially treatment-resistant infections, offering new avenues for therapeutic intervention.

Keywords: Antibiotic; Bacteria; Electroporation; Fusobacterium; Pulsed Electric Fields; Tumor Microbiome.

Fig. 1.

An overview of a) bacterial culture, b) cell infection, and c) pulsing treatment protocols. d) Representative images of agar plates 72 hr after treatment provide qualitative evidence for the efficacy of the control, independent, and combinatorial treatments. The ROI used in ImageJ is indicated here to quantify colony forming units.

Fig. 2.

a) Percentage of the sample uptaking propidium iodide for applied field strength with 10 ms pulses, ECT, and IRE. Non-infected cells appear to be more susceptible to the field than infected cells. b) Maximum permeability and cell death occur for both infected and non-infected cells at 450 V/cm.

Fig. 3.

Electro-Antibacterial Therapy is an effective method for inactivating intracellular tumor-associated F. nucleatum. The quantified normalized intracellular bacteria viability due to a) IRE with or without MTZ (5 μg/mL) (N = 2, n = 6) is moderately effective at reducing bacteria viability. EAT 10 ms pulses delivered at b) 300 V/cm (N = 3, n = 9) and c) 450 V/cm (N = 2, n = 6) result in a decrease in intracellular bacteria viability with applied field or antibiotic alone, but result in maximum clearance of intracellular bacteria when used in synergy. The colony forming units quantified here are bacteria that were intracellular at the time of treatment.