Radiation therapy in paediatric gliomas: our institutional experience

Static magnetic field controls cell cycle in cultured human glioblastoma cells

Magnetic field has been widely used in clinical diagnostics or for clinical treatment and is an important biomedical technology. Glioblastoma multiforme U87 and U251 are models of a fast growing malignant cancer. We focused on cellular level drafting of these cell lines as a time-dependent effect indicator of static magnetic fields (2000 ± 600 Gauss) by using their fast-growing properties. Cell viability showed a significant decrease (p < 0.01). The results coincided with the occurrence of apoptotic signals or protein expression of cyclin B1 and cyclin dependent kinase 1 in a non-apoptotic manner. Cdk1 was decreased in proportion to ankyrin G and cyclin B1 (Chi-square test, p = 0.0366). Our findings suggest that static magnetic stimulation creates a specific cyto-proliferative pattern, rather than producing randomized growth impairment.

Interference of Notch 2 inhibits the progression of gliomas and induces cell apoptosis by induction of the cell cycle at the G0/G1 phase

Glioblastoma is the most common type of malignant brain tumor with a poor prognosis. The Notch signaling pathway is often aberrantly activated in glioma cells. In order to determine the expression of Notch 2 and to evaluate its possible prognostic value in malignant glioblastoma, specimens from 32 patients and 20 controls were analyzed using immunohistochemical staining and reverse transcription quantitative polymerase chain reaction. The expression of Notch 2 in the glioma tissues was significantly higher compared with that in the normal brain tissues (P<0.01). Subsequently, endogenous Notch 2 interference was effectively performed by specific small hairpin (sh)RNA in the glioma cancer cell line U251. The results from an MTT assay and from Annexin V-fluorescein isothiocyanate/propidium iodide staining indicated that interference of Notch 2 significantly inhibited the proliferation and induced the apoptosis of U251 cells. In addition, the cell cycle was analyzed using flow cytometry and the results revealed that Notch 2 shRNA induced cell cycle arrest at the G0/G1 phase in U251 cells. Additionally, proteins associated with the cell cycle and cell proliferation were detected using western blot analysis. The data demonstrated that the expression of P21, cyclin D and phosphorylated retinoblastoma was significantly inhibited in the Notch 2 shRNA-transfected U251 cells. The results of the present study provide further insights into the effects of Notch 2 and a molecular reference for brain tumor therapy.