Gekeler V, Weger S, Probst H
Physiologisch-chemisches Institut, Universität Tübingen, Federal Republic of Germany.
Biochem Biophys Res Commun. 1990 Jun 15;169(2):796-802. doi: 10.1016/0006-291x(90)90401-8.
Three high-level multidrug-resistant sublines of the human T-lymphoblastoid cell line CCRF-CEM were selected independently with either actinomycin D, vincristine or adriamycin. They exhibited distinct quantitative differences of cross-resistance profiles, and showed amplification and marked expression of the mdrl/P-glycoprotein gene. DNA and RNA were prepared from the cell lines, and additionally from three cell samples of patients suffering from acute lymphatic leukemia. Applying the polymerase chain reaction (PCR) for amplification, we cloned and sequenced from these sources segments of the mdrl/P-glycoprotein gene around the codon 185 which codes for an amino acid residue possibly influencing the drug binding function of the P-glycoprotein. Altogether, only 2 single nucleotide differences in an intron were found in 2 out of 40 recombinants each harboring a 209 bp genomic or a 269 bp cDNA fragment of the mdrl/P-glycoprotein gene. Our result does not support the idea of clustered point mutations in this segment of the P-glycoprotein gene as a cause of different multidrug resistance profiles. We additionally examined another segment of the P-glycoprotein gene in its second half, essentially delivering the same negative result, though.
利用放线菌素D、长春新碱或阿霉素分别独立筛选出三个人类T淋巴母细胞样细胞系CCRF - CEM的高水平多药耐药亚系。它们表现出交叉耐药谱的明显定量差异，并显示出mdrl/P - 糖蛋白基因的扩增和显著表达。从这些细胞系以及三名急性淋巴细胞白血病患者的细胞样本中提取DNA和RNA。应用聚合酶链反应（PCR）进行扩增，我们从这些来源克隆并测序了mdrl/P - 糖蛋白基因第185密码子周围的片段，该密码子编码的氨基酸残基可能影响P - 糖蛋白的药物结合功能。总共，在40个重组体中，每个重组体都含有209 bp的mdrl/P - 糖蛋白基因基因组片段或269 bp的cDNA片段，只有2个重组体在一个内含子中发现了2个单核苷酸差异。我们的结果不支持P - 糖蛋白基因这一片段中的簇状点突变是导致不同多药耐药谱的原因这一观点。不过，我们另外检测了P - 糖蛋白基因后半部分的另一个片段，基本上也得到了相同的阴性结果。
