title: Knockdown of checkpoint kinase 1 is associated with the increased radiosensitivity of glioblastoma stem-like cells.
abstract: Glioblastoma multiforme is an aggressive brain tumor with a poor prognosis. The glioblastoma stem-like cells (GSCs) represent a rare fraction of human glioblastoma cells with the capacity for multi-lineage differentiation, self-renewal and exact recapitulation of the original tumor. Interestingly, GSCs are more radioresistant compared with other tumor cells. In addition, the remarkable radioresistance of GSCs has been known to promote radiotherapy failure and therefore is associated with a significantly higher risk of a local tumor recurrence. Moreover, the hyperactive cell cycle checkpoint kinase (Chk) 1 and 2 play a pivotal role in the DNA damage response including radiation and chemical therapy. Based on aforementioned, we hypothesized that knockdown of Chk1 or Chk2 might confer radiosensitivity on GSCs and thereby increases the efficiency of radiotherapy. In this study, we knocked down the expression of Chk1 or Chk2 in human GSCs using lentivirus-delivered short hairpin RNA (shRNA) to examine its effect on the radiosensitivity. After radiation, the apoptosis rate and the cell cycle of GSCs were measured with Flow Cytometry. Compared with control GSCs (apoptosis, 7.82 ± 0.38%; G2/M arrest, 60.20 ± 1.28%), Chk1 knockdown in GSCs increased the apoptosis rate (37.87 ± 0.32%) and decreased the degree of the G2/M arrest (22.37 ± 2.01%). In contrast, the radiosensitivity was not enhanced by Chk2 knockdown in GSCs. These results suggest that depletion of Chk1 may improve the radio-sensitivity of GSCs via inducing cell apoptosis. In summary, the therapy targeting Chk1 gene in the GSCs may be a novel way to treat glioblastoma.
authors.affiliation: Department of Neurosurgery, Huazhong University of Science and Technology, Hubei, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Guozheng
authors.initials: G
authors.lastname: Lai
authors.forename: Feng
authors.initials: F
authors.lastname: Wan
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Xiao
authors.forename: Lingcheng
authors.initials: L
authors.lastname: Zeng
authors.forename: Xiongwei
authors.initials: X
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
mesh_terms: D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects; D001932:Brain Neoplasms / Q000201:enzymology / Q000473:pathology / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D003131:Combined Modality Therapy; D055785:Gene Knockdown Techniques; D015316:Genetic Therapy / Q000379:methods; D005909:Glioblastoma / Q000201:enzymology / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D014411:Neoplastic Stem Cells / Q000201:enzymology / Q000473:pathology / Q000528:radiation effects; D011494:Protein Kinases / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D011836:Radiation Tolerance / Q000235:genetics*
chemical_list: D034741:RNA, Small Interfering; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases