Tumour-treating fields (TTFields) use alternating electric fields which interfere with dividing cells, thereby reducing tumour growth. Previous reports suggest that electrical forces on cell structure proteins interfered with the chromosome separation during mitosis and induced apoptosis. In the present report we evaluate electromagnetic exposure of cells in telophase/cytokinesis in order to further analyse the mechanism of action on cells. We performed numerical electromagnetic simulations to analyse the field distribution in a cell during different mitotic phases. Based thereon, we developed an electric lumped element model of the mitotic cell. Both the electromagnetic simulation and the lumped element model predict a local increase of the specific absorption rate ( SAR ) as a measure of the electromagnetically induced power absorption density at the mitotic furrow which may help to explain the anti-proliferative effect. In accordance with other reports, cell culture experiments confirmed that TTFields reduce the proliferation of different glioma cell lines in a field strength- and frequency-dependent manner. Furthermore, we found an additional dependence on the commutation time of the electrical fields. The report gives new insights into TTFields’ anti-proliferative effect on tumours, which could help to improve future TTFields application systems.

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Inflammation mediators enhance the activity of connexin (Cx) hemichannels especially in the epithelial and endothelial tissues. As potential release route for injury signals like (oligo)nucleotides, Cx hemichannels may contribute to long lasting inflammation. Specific inhibition of Cx hemichannels may therefore be a mode of prevention and treatment of long lasting, chronic sterile inflammation. The activity of Cx hemichannels was analysed in N2A and HeLa cells transfected with human Cx26 and Cx46 as well as in Calu-3 cells using the dye uptake as functional assay. Moreover, possible impact of the bioactive phenolic agents CVB2-61 and CVB4-57 on the barrier function of epithelial cells was analysed using Calu-3 cells. Both agents inhibited the dye uptake in N2A cells expressing Cx26 (> 5 µM) and Cx46 (> 20 µM). In Calu-3 cells, CVB2-61 and CVB4-57 reversible inhibited the dye uptake at concentrations as low as 5 µM, without affecting the gap junction communication and barrier function, even at concentrations of 20 µM. While CVB2-61 or CVB4-57 maintained a reduced dye uptake in Calu-3 cells, an enhancement of the dye uptake in response to stimulation of adenosine signaling was still observed after removal of the agents. The report shows that CVB2-61 and CVB4-57 reversible block Cx hemichannels. Deciphering the interaction mechanisms with Cx hemichannels could allow further development of phenolic compounds to target Cx hemichannels for a better and safer use in treatment of pathologies that involve Cx hemichannels.

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