盐酸氨基酮戊酸介导的光动力疗法增高U251细胞蛋白酶体的表达

Photodynamic therapy mediated with 5-aminolevulinic acid enhances the expression of proteasomes in glioma cell line U251 cells

目的探讨盐酸氨基酮戊酸(5-ALA)做为光敏剂的光动力疗法(PDT)对人胶质瘤细胞株U251细胞的杀伤效应及其对U251细胞蛋白酶体亚基低分子量多肽(LMP)2、7表达的影响。方法培养U251细胞,利用细胞计数药盒确定的5-ALA-PDT对U251细胞半抑制剂量为试验条件。分别收集5-ALA-PDT处理后3、6、9、12、15、18、21和24 h及对照组U251细胞LMP2和LMP7,RNA与蛋白质,分别行实时PCR、Western Blot分析。结果强度为20 mw/cm2激光照1、2、3和4 min后U251细胞抑制率分别为11.18%、19.6%、48.62%、66.21%。以强度为20 mw/cm2照射3 min为条件,照射后3、6、9、12、15、18、21和24 h,U251细胞蛋白酶体亚基LMP2、LMP7蛋白和mRNA表达水平均明显高于对照组(P<0.01)。结论以5-ALA为光敏剂的PDT能有效抑制体外培养U251细胞生长,并促进蛋白酶体的表达。

Objective To investigate the effect of photodynamic therapy （PDT） mediated with 5-aminolevulinic acid （5-ALA） on the expression of the proteasomes in glioma cell line U251 cells. Methods U251 cells were cultured. The half inhibiting concentration of 5-ALA for U251 cells was determined by Counting Kit-8（CCK-8） technique. The expressions of mRNA and protein of proteasomes including low moleculasr weight polypeptide （LMP）2 and 7 in U251 cells were determined respectively by reahime PCR and western blot 3, 6, 9, 12, 15, 18, 21 and 24 hours after PDT. Results The inhibitory rates for U251 cells growth were 11.18%, 19.6%, 48.62% and 66.2% respectively after PDT at 20 mw/cm2 radiation intensity for 1, 2, 3 and 4 minutes. The levels of LMP2 and LMP7 mRNA expressions were significantly higher in U251 cells 3, 6, 9 and 12 hours after PDT than those in the control group （P〈0.01）. The levels of LMP2 and LMP7 proteins expressions were significantly higher in u25i cells 6, 9, 12, 15, 18, 21 and 24 hours after PDT than those in the control group （P〈0.01）. Conclusion PDT mediated with 5-ALA can inhibit the growth of the U251 ceils and upregulate proteasomes expression in U251 cells.