Objective To investigate the relationship of programmed cell death 4(PDCD4) with the invasion of astrocytic glio-mas .Methods Using the immunohistochemical method to detect the expression of PDCD4 in astrocytic gliomas in different grades . Measuring the peritumoral low-density area on MRI scan ,then compared with the results of immunohistochemical expression .Re-sults The downregulation of PDCD4 was with the increasing of the malignant grade of astrocytic gliomas .The tumor grade malig-nancy was positively correlated with the grade of the peritumoral low-density area on MRI scan(P<0 .05) ,while the expression of PDCD4 was negatively correlated with the grade of astrocytic gliomas (P<0 .01) .Conclusion PDCD4 might serve as one of the in-dicators of invasion and malignant phenotype for astrocytic gliomas .

Objective:To explore the mechanism of miR-205-5p/E2F1 signal axis in regulating the glioma U251, U87 radiotherapy resistance.Methods:X-ray gradual ascending and intermittent induction method was used to irradiate the glioma U251 cells to establish U251/TR, U87/TR radiation-resistant cell lines. Then, the morphology, migration, invasion and proliferation abilities of cells (U251/TR, U87/TR radiation-resistant cells and U251, U87 radiation-sensitive cells) were analyzed. Luciferase gene detection system and point mutation technique were employed to analyze the mechanism of miR-205-5p and E2F1 gene activity on U251 and U87 radiation-resistant cell lines.Results:Compared with the radiation-sensitive U251 cells, the radiation-resistant cells U251/TR, U87/TR showed increased proliferation activity, enhanced migration and invasion abilities and decreased apoptosis under X-ray irradiation. miR-205-5p mimics transfection could down-regulate the expression of E2F1 factor in U251/TR cells, inhibit cell proliferation, invasion and migration and increase the radiosensitivity of U251/TR cells. miR-205-5p mimics transfection combined with with E2F1 down-regulation exerted anti-tumor effect and decreased cell tolerance by suppressing the Wnt/β-catenin signaling pathway activity.Conclusions:The glioma radiation-resistant cell line U251/TR, U87/TR can be established by X-ray gradual ascending and intermittent induction method. The miR-205-5p/E2F1 signal axis exerts tumor-suppressing effect through the classical Wnt/β-catenin signaling pathway, which can be used as an therapeutic target to increase the radiosensitivity of glioma.