Unraveling the Effects of a Noninvasive Brain Cancer Therapy

Greyscale image of a brain with a tumor exhibiting a 'ring-like' zone of contrast enhancement around a dark central area.
Magnetic resonance image of a brain with glioblastoma multiforme.
Credit: The Armed Forces Institute of Pathology

On average, people with glioblastoma multiforme (GBM), the most common primary brain tumor in adults, survive only 14 to 16 months after diagnosis. Previous studies reported that alternating electric fields (EFs) with intermediate frequency and low intensity—known as “tumor-treating fields” or TTFields—can stop the growth of GBM cells while leaving other cells intact. While treatments based on TTFields are clinically available, they are not widely used, in part because the mechanisms of action underlying their possible effects remain poorly understood.

To advance study of TTFields, the Basser Lab developed an inductive device to deliver EFs to cell cultures in a non-contacting manner. At low EF amplitudes, they observed no change in the growth of several human GBM cell lines (U87, U118, GSC827, and GSC923). At higher EF amplitudes, the effects were mixed. Growth of U87 cells increased, growth of GSC827 and GSC923 cells decreased, and growth of U118 cells did not change.
Analysis of gene expression—the degree to which certain genes are turned on or off—in GSC827 and GSC923 cells revealed EF-induced changes. However, these changes were also not consistent across cell lines or EF amplitudes.
These varied responses to EF treatment highlight the need to carefully assess the effects of TTFields and similar treatments on individual cell lines and in other biological and clinical contexts.

References

Ravin R, Cai TX, Li A, Briceno N, Pursley RH, Garmendia-Cedillos M, Pohida T, Wang H, Zhuang Z, Cui J, Morgan NY, Williamson NH, Gilbert MR, Basser PJ. "Tumor Treating Fields" delivered via electromagnetic induction have varied effects across glioma cell lines and electric field amplitudes. Am J Cancer Res DOI: 10.62347/NDII9862 (2024)

Ravin R, Cai TX, Pursley RH, Pohida T, Freidlin RZ, Wang H, Zhuang Z, Giles AJ, Williamson NH, Gilbert MR, Basser PJ. A novel in vitro device to deliver induced electromagnetic fields to cell and tissue cultures. Biophys J DOI: 10.1016/j.bpj.2020.11.002 (2020)

Learn more about the Maternal-Fetal Medicine and Translational Imaging group: https://www.nichd.nih.gov/about/org/dir/affinity-groups/MFMTI