Leptomeningeal metastatic cells adopt two phenotypic states

Background Leptomeningeal metastasis (LM), or spread of cancer cells into the cerebrospinal fluid (CSF), is characterized by a rapid onset of debilitating neurological symptoms and markedly bleak prognosis. The lack of reproducible in vitro and in vivo models has prevented the development of novel, LM-specific therapies. Although LM allows for longitudinal sampling of floating cancer cells with a spinal tap, attempts to culture patient-derived leptomeningeal cancer cells have not been successful. Aim We, therefore, employ leptomeningeal derivatives of human breast and lung cancer cell lines that reproduce both floating and adherent phenotypes of human LM in vivo and in vitro. Methods and Results We introduce a trypsin/EDTA-based fractionation method to reliably separate the two cell subsets and demonstrate that in vitro cultured floating cells have decreased proliferation rate, lower ATP content, and are enriched in distinct metabolic signatures. Long-term fractionation and transcriptomic analysis suggest high degree plasticity between the two phenotypes in vitro. Floating cells colonize mouse leptomeninges more rapidly and associate with shortened survival. In addition, patients harboring LM diagnosed with CSF disease alone succumbed to the disease earlier than patients with adherent (MRI positive) disease. Conclusion Together, these data support mechanistic evidence of a metabolic adaptation that allows cancer cells to thrive in their natural environment but leads to death in vitro.

Automated summary

By studying leptomeningeal derivatives of breast and lung cancer cell lines, researchers have found that floating cancer cells cultured in vitro have different proliferation rates, ATP content, and metabolic signatures. These floating cells are more likely to colonize the mouse leptomeninges and contribute to shortened survival. Additionally, patients with CSF disease only have a shorter life expectancy compared to patients with adherent disease.