title: Assessment of the intrinsic radiosensitivity of glioma cells and monitoring of metabolite ratio changes after irradiation by 14.7-T high-resolution ¹H MRS.
abstract: Gliomas are the most common type of primary brain tumor. Radiation therapy (RT) is the primary adjuvant treatment to eliminate residual tumor tissue after surgery. However, the current RT guided by conventional imaging is unsatisfactory. A fundamental question is whether it is possible to further enhance the effectiveness and efficiency of RT based on individual radiosensitivity. In this research, to probe the correlation between radiosensitivity and the metabolite characteristics of glioma cells in vitro, a perchloric acid (PCA) extracting method was used to obtain water-soluble metabolites [such as N-acetylaspartate (NAA), choline (Cho), creatine (Cr) and succinate (Suc)]. Spectral patterns from these processed water-soluble metabolite samples were acquired by in vitro 14.7-T high-resolution ¹H MRS. Survival fraction analysis was performed to test the intrinsic radiosensitivity of glioma cell lines. Good ¹H MRS of PCA extracts from glioma cells was obtained. The radiosensitivity of glioma cells correlated positively with the Cho/Cr and Cho/NAA ratios, but negatively with the Suc/Cr ratio. Irradiation of the C6 cell line at different X-ray dosages led to changes in metabolite ratios and apoptotic rates. A plateau phase of metabolite ratio change and a decrease in apoptotic rate were found in the C6 cell line. We conclude that in vitro high-resolution ¹H MRS possesses the sensitivity required to detect subtle biochemical changes at the cellular level. ¹H MRS may aid in the assessment of the individual radiosensitivity of brain tumors, which is pivotal in the identification of the biological target volume.
authors.affiliation: Department of Radiology, Qilu Hospital of Shandong University, Jinan, China.
authors.forename: Zhaotao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Qingshi
authors.initials: Q
authors.lastname: Zeng
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Chuanfu
authors.initials: C
authors.lastname: Li
authors.forename: Dechao
authors.initials: D
authors.lastname: Feng
authors.forename: Jianzheng
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004307:Dose-Response Relationship, Radiation; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D055442:Metabolome; D066244:Proton Magnetic Resonance Spectroscopy; D011836:Radiation Tolerance; D051381:Rats; D014965:X-Rays
keywords: 1H MRS; apoptosis; cell; glioma; in vitro; perchloric acid extracts; radiation therapy; radiosensitivity