Modulation of Exposure to Static Magnetic Field Affects Targeted Therapy of Solid Tumors In Vivo

Static magnetic fields (SMF) exhibit antitumoral activity and enhance the efficacy of chemotherapy by opening the tumor-blood barrier. This study aimed to analyze different SMF-exposure protocols on epidermal growth factor receptor (EGFR)-overexpressing tumors, as well as their combination with cetuximab.

Experiments were performed in skinfold chamber preparations of C57Bl/6-and CD-1nu/nu mice bearing LLC-1 tumors. Animals were exposed to 587 mT magnetic field following different exposure protocols. A subgroup received additional cetuximab injections. Using in vivo-fluorescence microscopy and planimetry, tumor angiogenesis, growth and microcirculation were repeatedly analyzed for 13 days.

In contrast to daily short SMF exposure, three-fold SMF exposure for 2 h led to a significant 46% reduction of tumor growth. Adding cetuximab to SMF exposure did not yield any benefit, although cetuximab monotherapy was highly effective (53% reduction of tumor growth), indicating a potential interference of SMF and EGFR signaling. No effects on microcirculation, angiogenesis or leukocyte-endothelium interactions were documented.

The use of SMF is promising in the treatment of solid tumors; however, it appears to interfere with EGFR-targeted therapy.