A 50 Hz sinusoidal magnetic field does not damage MG-63 three-dimensional tumor spheroids but induces changes in their invasive properties

Abstract

The possibility that a sinusoidal 50 Hz magnetic field with a magnetic flux density of 1 mT can damage MG-63 osteosarcoma spheroids and induce variations in the invasive properties of these three-dimensional model systems after 2 days of exposure was investigated. Specifically, possible damage induced by these fields was examined by determining changes in spheroid surface morphology (light microscopy), growth (spheroid diameter and protein content determination), lactate dehydrogenase release, and reduced glutathione amount. Possible changes in the invasive properties were studied by invasion chambers. The results show no induction of cell damage by ELF fields while invasion chamber assays demonstrate a significant increase in the invasive potential of exposed spheroids. In order to determine if the fibronectin or hyaluronan receptors are involved, Western blot analysis was conducted on these two proteins. No significant variations were observed in either receptor in MG-63 multicellular tumor spheroids.

Molecular aspects of tumor cell migration and invasion

“…In fact, by analyzing the adhesion molecule expression in 37 cell lines, isolated from nephrectomies, and the relative behaviour in the extra-renal stroma, a positive correlation was observed between invasive capacity and level of expression of both the molecules on the cell membrane. a study published in 2006 also highlighted the correlation between VLa2, VLa5 and cD44 adhesion molecules, and tumor metastases in human osteosarcoma cells [36]. Very important is also the association of cD44 with ezrin, radixin, myosin (erM) and merlin (moesin-ezrin-radixinlike protein) proteins [37][38][39].…”

Semiautomatic Growth Analysis of Multicellular Tumor Spheroids

“…similar problems are encountered when photographing spheroids with a microscope and a polaroid microcam. 16 compared to analysis with the ocular micrometer, here one has the option of saving the images and evaluating them later. a further approach is the method of flow cytometry, which was modified and established for spheroid analysis by J. p. Freyer et al 17 this procedure permits automatic analysis of very large numbers of spheroids but requires modification of the measuring device.…”

Changes of Leukocyte Adherence Ability Under the Influence of Magnetic Field in the Course of a Treatment of Patients with Laryngeal and Pharyngeal Carcinoma

“…Many epidemiological studies have been conducted concerning the relation between exposition to magnetic field and development of various tumors in people; the importance of these studies, however, was limited by the quality and variaty of magnetic field characteristics and measurements. A number of experimental studies have also been consequently conducted with exactly defined magnetic field (Huang et al, 2006;Sommer and Lerchl, 2006;Santini et al, 2006;Radeva and Berg, 2004;Tuncel et al, 2002;Traitcheva et al, 2003;Rao et al, 2002;Maruvada, et al, 2000;Harland et al, 1999;Lisi et al, 2000) dealing with the relation between the field and malignant tumors. Recently, on the contrary, there have appeared studies concerning possible positive effects of the magnetic field on patients with malignant tumors (Gorgun, 2005;Berg, 2005).…”