MOLECULAR MECHANISM IN RESISTANCE TO FOLATE ANALOGUES

这项赠款的长期目标是增加对 培养的细胞和肿瘤改变遗传特性的机制， 基因扩增的过程，主要是对抗性的研究 甲氨蝶呤 所要进行的研究包括：1）分析 构成二氢叶酸的启动子区的核苷酸序列 还原酶基因，以及对合成和代谢的研究 二氢叶酸还原酶mRNA在细胞周期中的作用; 2）分析二氢叶酸还原酶mRNA在细胞周期中的作用。 正常、恶性和转移性乳腺上皮细胞 经历二氢叶酸还原酶的自发或诱导扩增 通过使用荧光激活细胞分选仪检测的基因， 分子生物学技术; 3）甲氨蝶呤耐药性分析 与不稳定的表型相关， 甲氨蝶呤在4度，并具有改变的性质， 甲氨蝶呤的运输，采用技术的组合， 表征推定的过度生产蛋白质及其基因; 4）尝试 对拟放射性药物产生耐药性， 对于DNA重组能力增加的细胞 其通过基因扩增机制导致抗性表型。

The long-term objectives of this grant are to increase understanding of the mechanisms whereby cultured cells and tumors change genetic properties by the process of gene amplification, predominately with studies on resistance to methotrexate. The studies to be undertaken include: 1) an analysis of the nucleotide sequences constituting promoter regions of the dihydrofolate reductase gene, and studies on the synthesis and metabolism of the dihydrofolate reductase mRNA in the cell cycle; 2) an analysis of the propensity of normal, malignant, and metastatic breast epithelium to undergo spontaneous or induced amplification of the dihydrofolate reductase gene as detected by use of the fluorescence activated cell sorter and molecular biology technology; 3) an analysis of resistance to methotrexate that is associated with an unstable phenotype and increased ability to bind methotrexate at 4 degrees, and which has the properties of an altered transport of methotrexate, employing a combination of techniques to characterize the putative overproduced protein and its gene; 4) an attempt to generate resistance to radiomimetic drugs in such a fashion as to select for cells in which there is an increased capability for DNA recombination which results in the resistance phenotype by a gene amplification mechanism.