背景与目的:三磷酸腺苷结合转运蛋白G超家族成员2(adenosine triphosphate-binding cassette superfamily G member 2,ABCG2)在多种肿瘤细胞中表达,能通过外排抗癌药物参与肿瘤耐药。本研究的目的旨在探讨人胶质瘤细胞对焦脱镁叶绿酸甲...背景与目的:三磷酸腺苷结合转运蛋白G超家族成员2(adenosine triphosphate-binding cassette superfamily G member 2,ABCG2)在多种肿瘤细胞中表达,能通过外排抗癌药物参与肿瘤耐药。本研究的目的旨在探讨人胶质瘤细胞对焦脱镁叶绿酸甲酯(pyropheophorbide-a methyl ester,MPPa)介导的光动力疗法(photodynamic therapy,PDT)杀伤效应的敏感性及其与ABCG2的关系。方法:选取处于对数生长期的胶质瘤细胞株U87、A172,分别经MPPa-PDT或MPPa-PDT+烟曲霉毒素C(fumitremorgin C,FTC)处理后,采用CCK-8法检测细胞活性;采用蛋白[质]印迹法(Western blot)检测细胞内ABCG2的表达;流式细胞技术法检测未光照前各组细胞内MPPa的含量;AnnexinⅤ-FITC/PI双染流式细胞术检测细胞凋亡率;DCFH-DA染色观察细胞内活性氧(reactive oxygen species,ROS)的产生。结果:MPPa-PDT能抑制A172、U87细胞的活性,且呈一定的光能量依赖性,A172达到半数致死量所需光能量密度为U87的8倍;A172较U87细胞对MPPa-PDT不敏感;A172细胞内高表达的ABCG2影响MPPa在细胞内的聚集;抑制ABCG2后,不仅可以增强MPPa-PDT对A172细胞的杀伤作用,同时可增加MPPa-PDT触发产生的ROS的量及细胞对MPPa的摄取。结论:人胶质瘤细胞株A172对MPPa-PDT相对不敏感,并且产生这种现象的机制可能是ABCG2外排MPPa,减少MPPa的细胞内聚集,进而减弱光敏剂活化后对肿瘤细胞的杀伤作用。展开更多
目的探讨三磷酸腺苷结合盒转运体G1(ABCG1)在肿瘤坏死因子α(TNF-α)诱导的氧化应激中的作用及可能的机制。方法人脐静脉内皮细胞被特异性ABCG1 si RNA或ABCG1过表达质粒转染或使用LXR(肝X受体)激活剂T0901317预处理,随后给予肿瘤坏死因...目的探讨三磷酸腺苷结合盒转运体G1(ABCG1)在肿瘤坏死因子α(TNF-α)诱导的氧化应激中的作用及可能的机制。方法人脐静脉内皮细胞被特异性ABCG1 si RNA或ABCG1过表达质粒转染或使用LXR(肝X受体)激活剂T0901317预处理,随后给予肿瘤坏死因子(TNF-α)干预12 h。采用DCFHDAAM(2’7’-二氯荧光双乙酸盐)荧光探针检测细胞内活性氧簇(ROS)的水平,分光光度仪测量还原型烟酰胺腺嘌呤二核苷酸磷(NADPH)氧化酶活性,实时荧光定量聚合酶链反应法(q RT-PCR)和Western blot检测内皮细胞NADPH氧化酶亚型非吞噬细胞氧化酶4(NOX4)表达及超氧化物歧化酶(SOD)的表达。结果 ABCG1表达上调抑制TNF-α诱导的氧化应激,同时抑制促氧化应激的NADPH氧化酶的活性和NOX4的表达,促进抗氧化的SOD表达。相反,ABCG1表达下调进一步诱导ROS的产生,诱导NADPH氧化酶的活性和NOX4的表达,抑制SOD1表达。结论 ABCG1通过调节NADPH氧化酶/SOD抑制TNF-α诱导的氧化应激。展开更多
Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracell...Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracellular cholesterol in the foam ceils derived from rat VSMCs （rVSMCs） and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 （ABCA1）, adenosine triphosphate-binding cassette subfamily G member 1 （ABCG1） and peroxisome proliferator-activated receptor gamma （PPARy）. The rVSMCs were co-cultured with oxi- dized low density lipoprotein （LDL, 80 ~tg/mL） to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers （20, 40 and 60 pfu/cell） of recombinant adenovirus containing Mfn2 gene （Adv-Mfn2） were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group （P〈0.05）, and the ex- pression levels significantly increased when the titer of Adv-Mfn2 increased （P〈0.05）. At 24 or 48 h af- ter oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased （P〈0.05）, but it was sig- nificantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）, and it also significantly decreased when the titer of Adv-Mfn2 increased （P〈0.05）. The mRNA and pro- tein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. Though the mRNA and protein expression levels of PPARy was not significantly increased （P〉0.05）, the phosporylation levels of PPARy were signifi- cantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPAR＇/phosporylation and then increasing pro- tein expression levels of ABCAI and ABCG1, which may be helpful to suppress the formation of foam cells.展开更多
基金supported by the National Natural Science Foundation of China(No.30971244)
文摘Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracellular cholesterol in the foam ceils derived from rat VSMCs （rVSMCs） and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 （ABCA1）, adenosine triphosphate-binding cassette subfamily G member 1 （ABCG1） and peroxisome proliferator-activated receptor gamma （PPARy）. The rVSMCs were co-cultured with oxi- dized low density lipoprotein （LDL, 80 ~tg/mL） to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers （20, 40 and 60 pfu/cell） of recombinant adenovirus containing Mfn2 gene （Adv-Mfn2） were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group （P〈0.05）, and the ex- pression levels significantly increased when the titer of Adv-Mfn2 increased （P〈0.05）. At 24 or 48 h af- ter oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased （P〈0.05）, but it was sig- nificantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）, and it also significantly decreased when the titer of Adv-Mfn2 increased （P〈0.05）. The mRNA and pro- tein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. Though the mRNA and protein expression levels of PPARy was not significantly increased （P〉0.05）, the phosporylation levels of PPARy were signifi- cantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPAR＇/phosporylation and then increasing pro- tein expression levels of ABCAI and ABCG1, which may be helpful to suppress the formation of foam cells.
