Role of key genetic mutations on increasing migration of brain cancer cells through confinement.

ABSTRACT

Uncontrolled invasive cancer cell migration is among the major challenges for the treatment and management of brain cancer. Although the genetic profiles of brain cancer cells have been well characterized, the relationship between the genetic mutations and the cells' mobility has not been clearly understood. In this study, using microfluidic devices that provide a wide range of physical confinements from 20 × 5 µm2 to 3 × 5 µm2 in cross sections, we studied the effect of physical confinement on the migratory capacity of cell lines with different types of mutations. Human glioblastoma and genetically modified mouse astrocytes were used. Human glioblastoma cells with EGFRvIII mutation were found to exhibit high degree of migratory capacity in narrow confinement. From mouse astrocytes, cells with triple mutations (p53-/- PTEN-/- BRAF) were found to exhibit the highest level of migratory capacity in narrow confinement compared to both double (p53-/- PTEN-/-) and single (p53-/-) mutant cells. Furthermore, when treating the triple mutant astrocytes with AZD-6244, an inhibitor of the RAF/MEK/ERK pathway, we found significant reduction in migration through the confined channels when compared to that of controls (83% decrease in 5 × 5 µm2 and 86% in 3 × 5 µm2 channels). Our data correlate genetic mutations from different cell lines to their motility in different degrees of confinement. Our results also suggest a potential therapeutic target such as BRAF oncogene for inhibition of brain cancer invasion.