Fig 1.
Cellular ATP content in H69 and SW780 cells after calcium electroporation.
Cellular ATP levels determined 1, 2, 4, and 8 hours after calcium electroporation treatment of two human cell lines (H69, a small cell lung cancer cell line (A); and SW780, a bladder cancer cell line (B)). Extracellular calcium concentrations of 0 mM, 1 mM, 3 mM, or 5 mM and applied electric field of 0.8 kV/cm, 1.0 kV/cm, or 1.2 kV/cm. Results are illustrated as percentage of control (no electroporation, no added calcium). Normalized to control at each time point (%), mean—S.D., n = 6.
Fig 2.
Viability of H69 and SW780 cells after calcium electroporation.
Viability, assessed using MTS assay, of H69, a human small cell lung cancer cell line (A); and SW780, a human bladder cancer cell line (B) 24 hours after treatment with calcium electroporation. Final extracellular calcium concentrations of 0 mM, 1 mM, 3 mM, or 5 mM and applied electric field of either 0.8 kV/cm, 1.0 kV/cm, or 1.2 kV/cm. Cells thrice thawed and frozen, then sonicated were used as control (dead cells). Results are illustrated as percentage of control (no electroporation, no added calcium), electroporation (EP), mean + S.D., n = 6.
Fig 3.
SW780 viability as a function of pulsed electric field and extracellular calcium concentration.
Cell survival (%) versus electric field (E) at calcium electroporation using 0, 1, 3, or 5mM calcium in SW780 human bladder cancer cells assessed using MTS assay 24 hours after treatment. Electric field amplitude of 0.8 kV/cm, 1.0 kV/cm, 1.2 kV/cm, 1.4 kV/cm, or 1.6 kV/cm was applied. Fitting curves were derived using MATLAB software. Results are illustrated as percentage of control (no electroporation, no added calcium), mean ± S.D., n = 6.
Table 1.
SW780 cell sensitivity to electric field with increased extracellular calcium chloride concentrations.
Fig 4.
Scanning confocal images of U937 15 min after calcium electroporation.
U937, a human leukaemia cell line. Final extracellular calcium chloride concentrations of 0 mM or 3 mM and applied electric field of 1.0 kV/cm. Quinacrine fluorescence (top row), 10 μM; propidium iodide fluorescence (middle row), 7.5 μM; phase contrast cell images (bottom row).
Fig 5.
U937 cell response to calcium electroporation.
U937, a human leukaemia cell line. (A) Cellular quinacrine fluorescence intensity of U937 15 min after calcium electroporation. The extracellular quinacrine concentration was 10 μM during loading and electroporation. Final extracellular calcium concentrations of 0 mM or 3 mM and applied electric field of 1.0 kV/cm were used. Columns depict the average of 180 cells (9 experiments × 20 cells). Arbitrary units (AU), mean + S.D., n = 9. (B) U937 cell viability measured 24 h after calcium electroporation. Viability assessed for U937 using resazurin cell proliferation assay. Extracellular calcium concentrations of 0 or 3 mM. Applied electric field of 1.0 kV/cm. Results are illustrated as percentage of control (no electroporation, no added calcium), mean + S.D., n = 6.