Objective To investigate the impact of all-trans retinoic acid （ATRA） on MDM2 gene expression in astrocytoma cell line SHG-44, and to provide basic data for further research on the progression mechanism and gene the...Objective To investigate the impact of all-trans retinoic acid （ATRA） on MDM2 gene expression in astrocytoma cell line SHG-44, and to provide basic data for further research on the progression mechanism and gene therapy of human astrocytoma. Methods The differential expressions of MDM2 gene and protein in SHG-44 cells were detected by cDNA microarray and Western blot, respectively, before and after treatment of ATRA. The expressions of MDM2 protein in WHO grade Ⅱ and grade Ⅳ astrocytomas were determined by immunohistochemical streptavidin-peroxidase method. Some differentially expressed genes were selected randomly for Northern blot analysis. Results The intensity ratio of ATRA-treated to untreated SHG-44 cell was 0.37 in the cDNA microarray, suggesting that the expression of MDM2 gene was down-regulated in SHG-44 cells after treatment with ATRA. Some genes differentially expressed in the microarray were confirmed by Northern blot. Western blot demonstrated that the optical density ratios of MDM2 to β-actin in ATRA-treated and untreated SHG-44 were 14.02±0.35 and 21.40±0.58 （t = 24.728, P = 0.000）, respectively, suggesting that the expression of MDM2 protein was inhibited in ATRA-treated SHG-44 cells. Moreover, the percentages of MDM2-positive protein were 24.00% （6/25） and 56.52% （13/23） （x^2 = 5.298, P = 0.021） in WHO grade Ⅱ and grade Ⅳ astrocytomas, respectively, suggesting that the expression of MDM2 protein may increase along with the elevation of astrocytoma malignancy. Conclusion ATRA can inhibit MDM2 gene expression in SHG-44 cells, and MDM2 is related to astrocytoma progression.展开更多
BACKGROUND： Progenitors of the immortalized human glioma cell line, SHG-44, are significantly less sensitive to irradiation. Two hypotheses regarding the mechanism of this effect exist： several studies have suggeste...BACKGROUND： Progenitors of the immortalized human glioma cell line, SHG-44, are significantly less sensitive to irradiation. Two hypotheses regarding the mechanism of this effect exist： several studies have suggested that there is a subgroup with different radiosensitivities in identical cell group, and the progenitors of irradiate is a adaptive response subgroup, so its radiosensitivity is descend. A second hypothesis suggests that irradiated glioma progeny have a stronger ability to repair DNA damage. This would suggest that when progeny are continuously irradiated, resistance to irradiation-induced DNA increases, and radiosensitivity decreases. OBJECTIVE： To investigate radiosensitivity and growth features after irradiation to progeny of the human glioma cell line SHG-44. DESIGN, TIME AND SETTING： A randomized, controlled experiment, which was performed at the Department of Radiology Laboratory, the First Hospital Affiliated to Soochow University, between September 2004 and January 2006. MATERIALS： The glioma cell line SHG-44 was provided by the Institute of Neuroscience, First Affiliated Hospital of Suzhou University. Propidium iodide reagent was provided by Coulter Corporation. A linear accelerator, KD-2 type, was provided by Siemens, Germany. The flow cytometer EPICS-XL was provided by Coulter Corporation. METHODS： Brain glioma SHG-44 cells were divided into four groups： SHG-44, SHG-44-2, SHG-44-6, and SHG-44-10 . The SHG-44-2, SHG-44-6, and SHG-44-10 cells were vertically irradiated with varying doses of 2, 6 and 10 Gy by a linear accelerator （6 MVX）. The cells were passaged for 15 generations and cultured in RPMI-1640 culture media. MAIN OUTCOME MEASURES： Community re-double time, mean lethal dose （D0）, extrapolation number （N）, fraction surviving fraction irradiated by 2 Gy dose （SF2）, quasi-threshold dose （Dq）, and cell cycle. RESULTS： The Population doubling time （PDT） of SHG-44-2, SHG-44-6, and SHG-44-10 cell groups was not significant （P = 0.052）. Compare展开更多
Objective:To explore the suppressing effect ofγ-secretase inhibitor DAPT on proliferation of human glioma cell line SHG-44 in vitro and its mechanism.Methods:The SHG-44 cell was treated by DAPT with different concent...Objective:To explore the suppressing effect ofγ-secretase inhibitor DAPT on proliferation of human glioma cell line SHG-44 in vitro and its mechanism.Methods:The SHG-44 cell was treated by DAPT with different concentration.The proliferation of cells was detected by MTT assay;cell cycle and TSC of CD133^+were determined by flow cytometry analysis technique;the key factor in Notch signaling pathway(Notch-1,Delta-1,Hes-1)was measured by reverse transcrip tase-polymerase chain reaction and western blotting.Results:DAPT inhibited the growth and proliferation of SHG-44 cells significantly(P<0.05).And the inhibiting effect on SHG-44 cells produced by DAPT showed a dose-dependent manner.DAPT increased the rate of cells in G_0/G_1 phase of SHG-44 cells,while it decreased the rate of cells in S phase.TSC of CD133^+was significantly reduced after DAPT treated SHC-44 cells.The expression of protein and mRNA of Notch-1,Delta-1 and Hes-1 were gradually downregulated with the increase of DAPT doses.Conclusions:DAPT can downregulate these key factor in Notch signaling pathway,reduce the TSC of CD133+and inhibit the proliferation of SHC-44 cells.展开更多
基金a grant from the Bureau of Health, Sichuan Province, China (No. 050209).
文摘Objective To investigate the impact of all-trans retinoic acid （ATRA） on MDM2 gene expression in astrocytoma cell line SHG-44, and to provide basic data for further research on the progression mechanism and gene therapy of human astrocytoma. Methods The differential expressions of MDM2 gene and protein in SHG-44 cells were detected by cDNA microarray and Western blot, respectively, before and after treatment of ATRA. The expressions of MDM2 protein in WHO grade Ⅱ and grade Ⅳ astrocytomas were determined by immunohistochemical streptavidin-peroxidase method. Some differentially expressed genes were selected randomly for Northern blot analysis. Results The intensity ratio of ATRA-treated to untreated SHG-44 cell was 0.37 in the cDNA microarray, suggesting that the expression of MDM2 gene was down-regulated in SHG-44 cells after treatment with ATRA. Some genes differentially expressed in the microarray were confirmed by Northern blot. Western blot demonstrated that the optical density ratios of MDM2 to β-actin in ATRA-treated and untreated SHG-44 were 14.02±0.35 and 21.40±0.58 （t = 24.728, P = 0.000）, respectively, suggesting that the expression of MDM2 protein was inhibited in ATRA-treated SHG-44 cells. Moreover, the percentages of MDM2-positive protein were 24.00% （6/25） and 56.52% （13/23） （x^2 = 5.298, P = 0.021） in WHO grade Ⅱ and grade Ⅳ astrocytomas, respectively, suggesting that the expression of MDM2 protein may increase along with the elevation of astrocytoma malignancy. Conclusion ATRA can inhibit MDM2 gene expression in SHG-44 cells, and MDM2 is related to astrocytoma progression.
文摘BACKGROUND： Progenitors of the immortalized human glioma cell line, SHG-44, are significantly less sensitive to irradiation. Two hypotheses regarding the mechanism of this effect exist： several studies have suggested that there is a subgroup with different radiosensitivities in identical cell group, and the progenitors of irradiate is a adaptive response subgroup, so its radiosensitivity is descend. A second hypothesis suggests that irradiated glioma progeny have a stronger ability to repair DNA damage. This would suggest that when progeny are continuously irradiated, resistance to irradiation-induced DNA increases, and radiosensitivity decreases. OBJECTIVE： To investigate radiosensitivity and growth features after irradiation to progeny of the human glioma cell line SHG-44. DESIGN, TIME AND SETTING： A randomized, controlled experiment, which was performed at the Department of Radiology Laboratory, the First Hospital Affiliated to Soochow University, between September 2004 and January 2006. MATERIALS： The glioma cell line SHG-44 was provided by the Institute of Neuroscience, First Affiliated Hospital of Suzhou University. Propidium iodide reagent was provided by Coulter Corporation. A linear accelerator, KD-2 type, was provided by Siemens, Germany. The flow cytometer EPICS-XL was provided by Coulter Corporation. METHODS： Brain glioma SHG-44 cells were divided into four groups： SHG-44, SHG-44-2, SHG-44-6, and SHG-44-10 . The SHG-44-2, SHG-44-6, and SHG-44-10 cells were vertically irradiated with varying doses of 2, 6 and 10 Gy by a linear accelerator （6 MVX）. The cells were passaged for 15 generations and cultured in RPMI-1640 culture media. MAIN OUTCOME MEASURES： Community re-double time, mean lethal dose （D0）, extrapolation number （N）, fraction surviving fraction irradiated by 2 Gy dose （SF2）, quasi-threshold dose （Dq）, and cell cycle. RESULTS： The Population doubling time （PDT） of SHG-44-2, SHG-44-6, and SHG-44-10 cell groups was not significant （P = 0.052）. Compare
基金supported by Shaanxi Province Health Department Key Funds(sx201227273)
文摘Objective:To explore the suppressing effect ofγ-secretase inhibitor DAPT on proliferation of human glioma cell line SHG-44 in vitro and its mechanism.Methods:The SHG-44 cell was treated by DAPT with different concentration.The proliferation of cells was detected by MTT assay;cell cycle and TSC of CD133^+were determined by flow cytometry analysis technique;the key factor in Notch signaling pathway(Notch-1,Delta-1,Hes-1)was measured by reverse transcrip tase-polymerase chain reaction and western blotting.Results:DAPT inhibited the growth and proliferation of SHG-44 cells significantly(P<0.05).And the inhibiting effect on SHG-44 cells produced by DAPT showed a dose-dependent manner.DAPT increased the rate of cells in G_0/G_1 phase of SHG-44 cells,while it decreased the rate of cells in S phase.TSC of CD133^+was significantly reduced after DAPT treated SHC-44 cells.The expression of protein and mRNA of Notch-1,Delta-1 and Hes-1 were gradually downregulated with the increase of DAPT doses.Conclusions:DAPT can downregulate these key factor in Notch signaling pathway,reduce the TSC of CD133+and inhibit the proliferation of SHC-44 cells.
