Moderate hypothermia inhibits both proliferation and migration of human glioblastoma cells

Purpose Glioblastoma is the most aggressive malignant brain tumor. Despite multimodal treatments, median survival is only 15 months for glioblastoma patients, with tumor recurring in the resection margins after surgical removal. Hypothermia is emerging as an interesting and safe treatment for several conditions. In the context of glioblastoma, we propose that moderate hypothermia could inhibit both cell proliferation and migration, and thus help prevent secondary tumor growth. Methods In vitro experiments on A172, U251, U87 and T98G human glioblastoma cell lines explored the effects of severe (23 degrees C), moderate (28 degrees C), and mild (33 degrees C) hypothermia. We further investigated the effects of moderate hypothermia on cell proliferation, migration, morphology, and cell cycle distribution. Results Similar results were obtained with all four cell lines, indicating a consistent and broad effect of moderate hypothermia. Hypothermia inhibited both cell proliferation and non-oriented migration in a dose-dependent manner, with a significant reduction at 33 degrees C and almost total arrest at 28 degrees C. Cell proliferation arrest was long-lasting and oriented cell migration was also reduced at 28 degrees C. Moreover, moderate hypothermia significantly altered cell cycle distribution, with cells accumulating in the G2/M phase, leading to cell cycle arrest. Lastly, hypothermia at 28 degrees C also affected cell morphology by deteriorating cell membranes and altering cell shape. Conclusions The presented results demonstrate that moderate hypothermia could be a promising adjuvant therapy for glioblastoma treatment as it strongly inhibits both cell proliferation and migration. If in vivo preclinical results corroborate our findings, therapeutic hypothermia applied at the resection margins could probably delay tumor recurrence, combined with current treatments.