A study of novel transporters resposible for Uptake of the anticancer drugs a new strategy to increase the efficacy of anticancer drugs

1.（1）通过真实的时间RT-PCR分析，发现一种新的转运蛋白LST-2在肝癌、胃癌、结直肠癌和乳腺癌细胞系中高表达。（2）LST-2基因的表达与肿瘤细胞对几种抗癌药物的敏感性相关。2. LST-1和LST-2基因的导入对肿瘤细胞药物摄取和敏感性的影响（1）构建了LST-1和LST-2重组腺病毒AdLST-1和AdLST-2，并制备了对照病毒Adβ-gal。（2）AdLST-1和AdLST-2感染乳腺癌细胞株MB 231和ZR 75 -1后，LST-1和LST-2蛋白表达增强。在体外甲氨蝶呤（MTX）的抗增殖活性显着增加，无论是AdLST-1或AdLST-2感染的细胞。（3）AdLST-1和AdLST-2能增强MTX对SCID小鼠皮下肿瘤的抗增殖作用。(4)全身放射自显影显示AdLST-1和AdLST-2感染的皮下肿瘤模型对MTX的摄取增加。3.激活LST-1和LST-2启动子诱导LST-1和KST-2的表达（1）我们鉴定了影响LST-1和LST-2表达的启动子基序和转录因子。(2)We发现LST-1和LST-2的转录活性受胆汁酸、CDCA和DCA的诱导，两者的表达与肿瘤细胞，尤其是乳腺癌细胞对MTX的敏感性有关。这些结果可能提供一种新的策略，增加MTX的疗效和减少MTX的副作用。

1.Analysis of the expression of the transporters in human cancer lines(1)Analysis by real time RT-PCR showed high expression of a new transporter, LST-2 in liver, gastric, colorectal, ad breast cancer cell lines.(2)The sensitivity of the cancer cell lines to several anticancer drug was correlated with the expression of LST-2.2.Changes of the drug uptake and sensitivity by introduction of LST-1 and LST-2 mRNA(1)We created LST-1 and LST-2 recombinant adenoviruses, termed AdLST-1 ad AdLST-2, and a control virus (Adβ-gal).(2)LST-1 and LST-2 proteins were strongly expressed in the breast cancer cell lines, MB231 and ZR75-1, infected with AdLST-1 and AdLST-2. In vitro antiproliferative activity of methotrexate (MTX) was significantly increased in the cells infected with either AdLST-1 or AdLST-2.(3)AdLST-1 and AdLST-2 also increased the antiproliferative activity of MTX in a subcutaneous tumor model using SCID mouse.(4) A whole body autoradiography demonstrated that the uptake of MTX was increased in the subcutaneous tumor model infected with AdLST-1 or AdLST-2.3.Induction of LST-1 and KST-2 expression by activation of LST-1 and LST-2 promoters(1)We identified the promoter motifs and transcription factors that affect LST-1 and LST-2 expression.(2)We found that the LST-1 and LST-2 transcription activities were induced by bile acids, CDCA and DCA.Taken together, The expression of LST-1 and LST-2 was found to associated with the MTX sensitivity of cancer cells, especially breast cancer cells. These results might provide a new strategy that increases the efficacy of MTX and decreases the side effects of MTX.