胞外囊泡通过三磷酸腺苷结合盒转运子G2调控肺腺癌耐药的作用研究

Effects of Extracellular Vesicles on the Drug Resistance of Lung Adenocarcinoma Cells by Modulating the ATP Binding Cassette Transporter G2

目的探讨携带三磷酸腺苷结合盒转运子G2(ATP binding cassette transporter G2,ABCG2)胞外囊泡(extracellular vesicle,EVs)调控肺腺癌耐药作用及其分子机制。方法取人肺腺癌细胞A549,建立顺铂(cisDiaminedichloroplatinum,CDDP)耐药的肺腺癌细胞A549/CDDP;利用梯度离心法提取A549及A549/CDDP细胞释放的EVs,分别命名为EVs1及EVs2。EVs1及EVs2干预A549细胞48 h后,细胞分别命名为A549-EVs1及A549-EVs2。利用pCDNA3.1-ABCG2重组质粒转染A549细胞,建立A549/ABCG2细胞;转染空载体的A549细胞命名为A549/pCDNA3.1细胞。以MTT检测计算细胞24 h对CDDP的耐药指数;real-time PCR检测细胞、EVs中ABCG2基因表达;建立荷瘤裸鼠模型,分别接种A549及A549-EVs2细胞至裸鼠皮下,记为对照组及实验组。成瘤后腹腔注射3 mg/kg CDDP,每周1次,共2次。取皮下移植瘤组织,real-time PCR检测ABCG2基因表达,流式细胞术检测皮下移植瘤细胞凋亡率。结果以亲代细胞A549为参照,A549/CDDP、A549/ABCG2、A549/pCDNA3.1、A549-EVs1、A549-EVs2细胞24 h对CDDP的耐药指数分别为7.17、10.06、1.02、1.19、5.40。各细胞中、EVs中ABCG2基因的表达水平相比较,A549/CDDP细胞高于A549细胞,A549/ABCG2细胞高于A549/pCDNA3.1和A549细胞,EVs2高于EVs1,A549-EVs2细胞高于A549-EVs1细胞(P<0.01)。实验组移植瘤体积、细胞中ABCG2基因表达大/高于对照组,而细胞凋亡率低于对照组(P<0.05)。结论携带ABCG2基因的EVs可以调控肺腺癌细胞耐药。

Objective To investigate the regulatory role of extracellular vesicles(EVs)carrying ATP binding cassette transporter G2(ABCG2)on the drug resistance of lung adenocarcinoma cells and the relevant molecular mechanisms.Methods A549 cells,human lung adenocarcinoma cells,were used to form cisplatin(or cisDiaminedichloroplatinum,CDDP)-resistant lung adenocarcinoma cells,i.e.,A549/CDDP cells.EVs from A549 and A549/CDDP cells were extracted by gradient centrifugation method and were hence named EVs1 and EVs2,respectively.The A549 cells were treated with EVs1 and EVs2 for 48 hours,and the cells were named A549-EVs1 and A549-EVs2 cells,respectively.A549/ABCG2 cells were established by transfecting A549 cells with pCDNA3.1-ABCG2 recombinant plasmids.On the other hand,A549 cells transfected with empty vectors were named A549/pCDNA3.1 cells.MTT assay was conducted to calculate the 24-hour cell drug resistance index for CDDP.The ABCG2 gene expression in cells and EVs were assessed with real-time PCR.A549 and A549-EVs2 cells were transplanted subcutaneously into nude mice,which were labeled the control group and the experimental group accordingly.After tumor formation,3 mg/kg CDDP was intraperitoneally injected once a week for two times.The ABCG2 gene expression of subcutaneous transplanted tumor cells was examined by real-time PCR.The cell apoptosis rate of subcutaneous transplanted tumor cells was examined by flow cytometry.Results Using the parental A549 cells as reference,the 24-h CDDP-resistance indexes of 549/CDDP,A549/ABCG 2,A549/pCDNA3.1,A549-EVs1,A549-EVs2 cells were 7.17,10.06,1.02,1.19 and 5.40,respectively.When comparing the ABCG2 gene expression levels in all cells and EVs,the findings were higher in A549/CDDP cells than those in A549 cells,higher in A549/ABCG2 cells than those in A549/pCDNA3.1 or A549 cells,higher in EVs2 than those in EVs1,and higher in A549-EVs2 than those in A549-EVs1 cells(P<0.01).The volume of transplanted tumor and the ABCG2 gene expression level in the experimental group were higher than those in the control group,while the apoptosis rate was lower than that in the control group(P<0.01).Conclusion EVs carrying ABCG2 gene can regulate the drug resistance of lung adenocarcinoma cells.