Simvastatin suppresses spinal cord metastasis of medulloblastoma at clinically significant doses.

Abstract

Medulloblastomas (MBs) are aggressive brain cancers and represent the most common primary malignant tumour in children. Current treatment protocols involve an intensive regimen of surgery, radiation therapy and chemotherapy, guided by histopathology and risk stratification. Unfortunately, disease relapse proves fatal in 30% of cases, and treatment efficacy is compromised as MB cells develop resistance. Therefore, there is a critical need for more effective and tolerable therapies, especially for the treatment of aggressive MBs associated with a poor prognosis. Lipid metabolism reprogramming, characterized by increased cholesterol synthesis, lipid uptake and the activation of de novo lipogenesis, is a newly identified hallmark of cancers. Cholesterol is an essential structural component of membranes that contributes to membrane integrity and fluidity. Recently, increasing evidence has indicated that cholesterol is a major determinant by modulating cell signalling events governing the hallmarks of cancer. Our research demonstrates there is an overexpression of cholesterol metabolism in group 3 (G3), and group 4 (G4) MB subgroups compared to Sonic Hedgehog (SHH)-MB subgroup. In these tumours, cholesterol metabolism supports cell migration through the Rho-GTPase signalling pathway. Notably, we observed that shifting the culture conditions from 2D to 3D significantly upregulates lipid metabolism. Furthermore, spheroids derived from G3/G4-MBs and SHH-MBs show similar sensitivity to low doses of simvastatin. We validated these findings in a xenograft mouse model, where treatment with low doses of simvastatin led to increased survival time and remarkably, also reduced the metastatic spread of MB cells to the spinal cord. These results suggest that simvastatin holds potential as an adjuvant treatment for patients with medulloblastoma.