Remote Actuation of Apoptosis in Liver Cancer Cells via Magneto-Mechanical Modulation of Iron Oxide Nanoparticles

Abstract

Lysosome-activated apoptosis represents an alternative method of overcoming tumor resistance compared to traditional forms of treatment. Pulsed magnetic fields open a new avenue for controlled and targeted initiation of lysosomal permeabilization in cancer cells via mechanical actuation of magnetic nanomaterials. In this study we used a noninvasive tool; namely, a benchtop pulsed magnetic system, which enabled remote activation of apoptosis in liver cancer cells. The magnetic system we designed represents a platform that can be used in a wide range of biomedical applications. We show that liver cancer cells can be loaded with superparamagnetic iron oxide nanoparticles (SPIONs). SPIONs retained in lysosomal compartments can be effectively actuated with a high intensity (up to 8 T), short pulse width (~15 µs), pulsed magnetic field (PMF), resulting in lysosomal membrane permeabilization (LMP) in cancer cells. We revealed that SPION-loaded lysosomes undergo LMP by assessing an increase in the cytosolic activity of the lysosomal cathepsin B. The extent of cell death induced by LMP correlated with the accumulation of reactive oxygen species in cells. LMP was achieved for estimated forces of 700 pN and higher. Furthermore, we validated our approach on a three-dimensional cellular culture model to be able to mimic in vivo conditions. Overall, our results show that PMF treatment of SPION-loaded lysosomes can be utilized as a noninvasive tool to remotely induce apoptosis.

Cancer treatment by magneto-mechanical effect of particles, a review

“…53 These materials were chosen by several groups. 21,29,32,41,43,44,48,51 However, in order to improve the magnetic actuation efficiency, larger magnetic susceptibilities than those of iron oxides may be required, in particular for low magnetic eld operation. Magnetic materials such as nickel, 19,33 cobalt, 27,39 or NiFe alloys, 22,27,36,55 represent good alternatives.…”

“…Although particles with a shape anisotropy are preferable to transfer a mechanical action on cells, several studies have observed a lethal effect on cancer cells by TMMEP using spherical particles. 43,44,46,[49][50][51] It should be noted that such spherical particles may however form small chains due to their magnetostatic interactions in an applied magnetic eld, and thus act as a unique elongated particle. The spherical particles used in TMMEP were mainly commercially available SPIONs fabricated by chemical routes, single or in cluster, actuated by applied magnetic elds of low frequency.…”

“…3(b)). 33,46,49,51 Kilinc et al 34 used a Fe-Co-V tip wound with a copper coil to apply the magnetic eld (the amplitude is not indicated). 34 In the latter case, the magnetic eld was applied very locally (500 mm from the tip).…”

“…Indeed, the intensity of the LysoTracker and LysoSensor Green markers decreased in this condition, as well as lysosome size. Lysosome disturbance was conrmed by Shen et al 30 aer 30 min of eld application at 15 Hz on cells exposed to iron oxide nanoparticles doped with zinc, through galectin labelling and imaging by transmission electron microscopy, and by Lunov et al 51 by studying acridine orange uorescence. These authors also observed a reduction of mitochondrial membrane potential, mitochondrial dysfunction and ROS accumulation aer LMP initiation.…”

Iron Oxide Nanoparticle-Induced Autophagic Flux Is Regulated by Interplay between p53-mTOR Axis and Bcl-2 Signaling in Hepatic Cells

“…After cells were incubated with cell culture media (EMEM, 10% FBS) containing different concentrations of nanoparticles for 24 h. For lysosomal stability assessment, we utilized an acridine orange (AO) assay. The AO assay was performed in accordance with our previously verified protocol [6,34]. Briefly, cells with incorporated nanoparticles were labeled with 5 µg mL −1 AO in culture medium for 15 min at 37 • C. Following nanoparticle treatment, cells were cultured at 37 • C for indicated periods of time and the intensity of orange fluorescence was then measured using a microplate reader SpectraFluor Plus (TECAN, Mannedorf, Switzerland).…”