叶酸受体及二氢叶酸还原酶与人乳腺癌细胞MCF-7/ADR多药耐药的关系

The role of folate receptor and dihydrofolate reductase in multidrug resistance of the human breast cancer cell line MCF-7/ADR

目的以人乳腺癌多药耐药细胞系MCF-7/ADR及其敏感亲本系MCF-7为对象,探讨叶酸受体(FOLRα)及其下游基因二氢叶酸还原酶(DHFR)的表达与乳腺癌细胞多药耐药的关系。方法 MTT法测定阿霉素的细胞毒性作用及DHFR抑制剂对MCF-7/ADR细胞多药耐药的逆转作用;RT-PCR检测细胞FOLRα和DHFR mRNA的表达水平;免疫细胞化学检测FOLRα、P-gp的表达水平。结果 MCF-7细胞增殖速度快于MCF-7/ADR细胞,MCF-7细胞FOLRα mRNA转录水平较MCF-7/ADR细胞高,而MCF-7/ADR细胞DHFR mRNA较MCF-7细胞转录水平高;免疫细胞化学显示MCF-7细胞FOLRα的表达高于MCF-7/ADR细胞,而MCF-7/ADR细胞P-gp的表达较MCF-7细胞高;MCF-7/ADR对甲氨蝶啶无耐药性,甲氨蝶啶对MCF-7/ADR细胞多药耐药有逆转作用。结论 MCF-7/ADR细胞FOLRα的表达水平下调可能与细胞增殖水平有关,其下游基因DHFR表达水平与MCF-7/ADR细胞的MDR可能存在相关性。

Aim The adriamycin-resistant human breast cancer cell line MCF-7/ADR was used as the experiment subject to investigate the expressions of FOLRα receptor gene and its downstream gene dihydrofolate reductase and their correlation with the breast cancer cell multidrug-resistance.Methods MTT assay was used to investigate the cytotoxicity of ADR and reversal effect of trimethoprim on MCF-7/ADR cells;real time PCR was used to detect transcriptional levels of folate receptor mRNA and dihydrofolate reductase mRNA of MCF-7/S cells and MCF-7/ADR cells,the protein level of P-gp and FOLRα was detected with immunohistochemisty.Results FOLRα receptor mRNA transcriptional levels of MCF-7 cells were higher than those of MCF-7/ADR cells,dihydrofolate reductase mRNA transcriptional levels of MCF-7/ADR cells were increased.It showed that the protein level of P-gp of MCF-7/ADR cells was higher than that of MCF-7/S cells,while the protein level of FOLRα of MCF-7/ADR cells was lower than that of MCF-7/S cells;MCF-7/ADR cells had no drug resistance to MTX,which could in turn reverse their multidrug resistance.Conclusions The down-regulated expression level of FOLRα receptor may be related to the level of MCF-7/ADR cell proliferation.The expression level of DHFR gene may be related to MDR of MCF-7/ADR cells.