Glioblastomas (GB) are an aggressive brain tumour with a dire prognosis –a median survival of 15 months. The GB standard of treatment includes surgical resection, followed by adjuvant radiotherapy and chemotherapy with Temozolomide (TMZ). Nonetheless, the current treatment drawbacks include developing tumour’s resistance, cancer recurrence, and drug and radiotherapy side effects. Hence, there is an ongoing ordeal for developing alternative therapies for GB.
Our study utilizes magnetic fields generated by a magnetic stimulator used clinically in treatment of depression. Recent studies have demonstrated that magnetic fields can induce anti-cancer effects in various types of malignant cells [1].
The current study aims to determine the effects of combined repetitive magnetic stimulation (RMS) performed with the use of the clinically approved equipment for transcranial magnetic stimulation. We also explore the effects of RMS in combination with TMZ and a repurposed drug Pirfenidone (PRF). PRF is used in treatment of pulmonary fibrosis. It has been proven to suppress inflammation and the Transforming Growth factor-B1 pathway, a critical mechanism in GB progression.
Human GB cell lines U87 and U251 were treated with TMZ or PRF. After 24 hours, RMS was applied, with varying frequencies of magnetic pulses (1-20 Hz), followed by a cell viability assay 72 hours later.
Our results show that for both cell lines, cell viability decreased in RMS-exposed cells compared to the controls. Moreover, cell viability significantly decreased for RMS-exposed and drug-treated cells, compared to drug-treated non-RMS cell counterparts. The highest decrease in cell viability was demonstrated at a magnetic pulses’ frequency of 1 Hz in both cell lines. Additionally, there was a greater reduction of viability in U87 cell lines compared to U251.
Overall, the experiment confirms the anti-cancer effects of magnetic stimulation at a super-low frequency and sub-Tesla magnetic flux density. We hypothesize that RMS affects cell membranes in a way that also can enhance drug uptake and/or efficacy on cancer cells, yet further research is required. This study highlights the strong potential of application of specific range of magnetic fields as an adjuvant modality for GB treatment. In addition, it shows that RMS treatment is combinable with the existing chemotherapy protocols for GB. It may deliver a new hope for patients affected by this deadly disease.