Modeling Cancerous Neural Invasion In Vitro: A Method to Co-culture Dorsal Root Ganglia and Cancer Cells

Neural invasion is the mechanism of cancer metastasis wherein neurotrophic cancer cells demonstrate an intrinsic ability to grow in and around nerves. To observe this phenomenon in vitro, first, take an isolated murine dorsal root ganglion or DRG - a cluster of cell bodies of sensory neurons.

Place the DRG in an ice-cold medium to retain its viability. Now, transfer the DRG into a drop of chilled extracellular matrix or ECM, which serves as a  three-dimensional scaffold around the DRG. Next, seed the neurotrophic cancer cells into the ECM at an appropriate distance around the DRG.

Allow the ECM to solidify in order to embed the DRG and cancer cells within. Finally, add a suitable growth medium to the ECM and incubate. The nutritive growth media and the ECM proteins provide an optimum microenvironment for the explants.

During incubation, the reciprocal interaction between the explants promotes DRG to sprout small nerve projections or neurites that outgrow radially towards the cancer cells. Simultaneously, cancer cells migrate unidirectionally away from their colonies and invade the newly formed neurites.