论文部分内容阅读
目的研究氨甲蝶呤(MTX)对映体[L-(+)-MTX和D-(-)-MTX]耐药与二氢叶酸还原酶(DHFR)基因表达的关系。方法用浓度递增结合低剂量持续诱导法获得A549细胞对不同构型及不同浓度的MTX对映体的耐药细胞株,荧光定量PCR检测耐药细胞株中DHFR基因的相对含量。结果对两种不同对映体的获得性耐药存在差异,D型耐药细胞耐药指数高于L型;对映体各浓度耐药细胞间耐药指数也有差异。15μmol/L L型、D型MTX首次诱导耐药细胞的DHFR相对含量低于亲本细胞,对该浓度对映体耐药的各细胞组间没有差别(P>0.05)。35～45μmol/L浓度耐药细胞的DHFR相对含量增加,45μmol/L D型耐药细胞DHFR相对含量高于对应浓度L型耐药细胞,差异有显著性(P<0.05)。结论首次诱导MTX耐药以抑制DHFR基因为主。DHFR基因表达具有手性差异。DHFR基因的检测有望作为肿瘤治疗监测的指标。
OBJECTIVE: To investigate the relationship between the resistance of methotrexate (MTX) enantiomers [L-(+)-MTX and D-(-)-MTX] and the expression of dihydrofolate reductase (DHFR) gene. Methods The drug-resistant cell lines with different configurations and different concentrations of MTX enantiomers were obtained in A549 cells by increasing concentrations combined with low-dose continuous induction method. The relative content of DHFR gene in drug-resistant cell lines was detected by fluorescent quantitative PCR. Results There were differences in the acquired resistance to two different enantiomers. The resistance index of D-type drug resistant cells was higher than that of L-form. The resistance index of resistant cells in different concentrations of enantiomers also varied. The relative content of DHFR in 15 μmol/L L-type and D-type MTX-inducing cells was lower than that in the parental cells, and there was no difference in the antielastoma-resistant cell groups (P>0.05). The relative content of DHFR was increased in 35-45 μmol/L drug-resistant cells, and the relative content of DHFR in 45 μmol/L D-type drug-resistant cells was higher than that in L-type drug-resistant cells of corresponding concentrations (P<0.05). Conclusion MTX resistance was induced for the first time to inhibit the DHFR gene. DHFR gene expression has a chiral difference. The detection of DHFR gene is expected to serve as an indicator of tumor treatment monitoring.