Gorlick R, Goker E, Trippett T, Steinherz P, Elisseyeff Y, Mazumdar M, Flintoff W F, Bertino J R
Program of Molecular Pharmacology and Therapeutics, Memorial Sloan-Kettering Cancer Center, New York 10021, USA.
Blood. 1997 Feb 1;89(3):1013-8.
Methotrexate (MTX) transport was examined in 27 patients with untreated acute lymphocytic leukemia (ALL) and 31 patients with relapsed ALL using a previously described fluorescent MTX analog (PT430) displacement assay (Blood 80:1158, 1992). Only 13% of untreated patients were considered to have impaired MTX transport, whereas more than 70% of relapsed patients had evidence of impaired MTX transport. To further characterize the basis for this defect, Northern analyses for the reduced folate carrier (RFC) were performed on the RNA available from the leukemic blasts of 24 patients in whom MTX transport had been measured. Six of nine samples with impaired MTX transport had decreased RFC expression (one had no detectable RFC expression), while three had no decrease in RFC expression. None of 15 samples with normal MTX transport had decreased RFC expression. A reverse-transcriptase polymerase chain reaction (RT-PCR) assay was developed to quantitate RFC mRNA expression more accurately. Decreased RFC expression was demonstrated in six of the nine samples with impaired MTX transport, confirming the results obtained by Northern blot. These data indicate decreased RFC expression associated with impaired MTX transport is observed in relapsed ALL following treatment with MTX-containing therapy.
使用先前描述的荧光甲氨蝶呤类似物（PT430）置换试验，对27例未经治疗的急性淋巴细胞白血病（ALL）患者和31例复发ALL患者的甲氨蝶呤（MTX）转运进行了检测（《血液》80:1158，1992）。未经治疗的患者中只有13%被认为存在MTX转运受损，而超过70%的复发患者有MTX转运受损的证据。为了进一步明确这种缺陷的基础，对24例已检测MTX转运的患者白血病原始细胞中获取的RNA进行了还原型叶酸载体（RFC）的Northern分析。MTX转运受损的9个样本中有6个RFC表达降低（1个未检测到RFC表达），而3个RFC表达未降低。15个MTX转运正常的样本中无一例RFC表达降低。开发了一种逆转录聚合酶链反应（RT-PCR）检测方法，以更准确地定量RFC mRNA表达。MTX转运受损的9个样本中有6个显示RFC表达降低，证实了Northern印迹法获得的结果。这些数据表明，在接受含MTX治疗的复发ALL中，观察到RFC表达降低与MTX转运受损有关。
