Multivoxel magnetic resonance spectroscopy identifies enriched foci of cancer stem-like cells in high-grade gliomas

Abstract

Objective: This study investigated the correlation between choline/creatine (Cho/Cr) ratios determined by multivoxel proton magnetic resonance spectroscopy (1H-MRS) and the distribution of cancer stem-like cells (CSLCs) in high-grade gliomas. Patients and methods: Sixteen patients with high-grade gliomas were recruited and underwent 1H-MRS examination before surgery to identify distinct tumor regions with variable Cho/Cr ratios. Using intraoperative neuronavigation, tumor tissues were accurately sampled from regions with high and low Cho/Cr ratios within each tumor. The distribution of CSLCs in samples from glioma tissue regions with different Cho/Cr ratios was quantified by neurosphere culture, immunohistochemistry, and Western blot. Results: The mean neurosphere formation rate in tissues with high Cho/Cr ratios was signifi-cantly increased compared with that in low Cho/Cr ratio tissues (13.94±5.94 per 100 cells vs 8.04±3.99 per 100 cells, P,0.001). Immunohistochemistry indicated that tissues with high Cho/ Cr ratios had elevated expression of CD133, nestin, and CD15, relative to low Cho/Cr ratio tissue samples (23.6%±3.8% vs 18.3%±3.3%, 25.2%±4.5% vs 19.8%±2.8%, 24.5%±3.8% vs 17.8%±2.2%, respectively; all P,0.001). Western blot demonstrated that relative CD133 and nestin protein expression in high Cho/Cr ratio regions was significantly higher than that in low Cho/Cr ratio tissue samples (0.50±0.17 vs 0.30±0.08, 0.45±0.13 vs 0.27±0.07, respectively; both P,0.001). The protein expression levels of CD133 and nestin were highly correlated with Cho/Cr ratios (r=0.897 and r=0.861, respectively). Conclusion: Cho/Cr ratios correlate with the distribution of CSLCs in high-grade gliomas, and this may assist in identifying foci enriched with CSLCs and thus improve the management of high-grade gliomas.