TRIPTYCENE ANALOGS--NOVEL BIFUNCTIONAL ANTICANCER DRUGS

雷公藤红素(TT)没有活性，但我们在体外合成了新的TT类似物(代号TT1至TT16)，它们在NM范围内具有抗白血病活性。先导化合物TT双醌(TT2)不仅能抑制L1210细胞的大分子合成，诱导DNA断裂，降低L1210细胞的生长和活力(IC50：100 nM)，而且还能阻断核苷的细胞转运，这是DAU所不能起到的作用。由于这些TT类似物在核苷转运和DNA切割方面具有独特和高度有用的双重作用，因此这些TT类似物可能有价值开发一类新的合成的有效于多种化疗的双功能抗癌药物。主要目的是1)证明TT2在体内的抗癌潜力，2)表征其分子作用机制，3)寻找更有效的TT2类似物。具体目的是：a)确定水溶性TT2衍生物可以抑制体内肿瘤的发展，并延长受到腹水(L1210)或具有转移潜力的实体瘤(Lewis肺癌和B16F10黑色素瘤)攻击的小鼠的生存时间。B)阐明TT2与核苷转运(平衡和钠离子依赖的转运体、嘌呤和嘧啶的双向流动、与核苷转运体的竞争)、DNA(结合、嵌入、链断裂和交联链、拓扑异构酶活性)以及肿瘤细胞(药物摄取/滞留/分解代谢、细胞周期分析、caspase-8和-3激活、细胞凋亡、抗代谢作用的增强以及P-糖蛋白阳性和阴性多药耐药(MDR)细胞的有效性)相互作用的分子机制。C)合成新的TT2类似物并在体外进行筛选，以阐明药物摄取、核苷转运/DNA合成、DNA片段化和细胞生长/存活的构效关系。由于核苷转运的抑制在DNA损伤的醌类抗肿瘤药物中是不常见的，在体外使用具有抗白血病活性的双功能TT2类似物在体外可能在多药化疗中提供相当大的优势，以增强抗代谢物的作用并使MDR肿瘤细胞增敏。

Triptycene (TT) is inactive but we synthesized new TT analogs (code names TT1 to TT16) that have antileukemic activity in the nM range in vitro. The lead compound, a TT bisquinone (TT2), not only inhibits macromolecule synthesis, induces DNA fragmentation, and decreases the growth and viability (IC50: 100 nM) of L1210 cells in vitro like the quinone antitumor drug daunomycin (DAU) but can also block the cellular transport of nucleosides, an effect which DAU cannot do. Since they have unique and highly useful dual effects on nucleoside transport and DNA cleavage, these TT analogs might be valuable to develop a novel synthetic class of bifunctional anticancer drugs effective in polychemotherapy. The major objectives are 1) to demonstrate the anticancer potential of TT2 in vivo, 2) to characterize its molecular mechanism of action, and 3) to identify more potent TT2 analogs. The specific aims are: A) To establish that water-soluble TT2 derivatives can inhibit tumor development in vivo and prolong the survival of mice challenged with ascites (L1210) or solid tumors with metastatic potential (Lewis lung carcinoma and B16F10 melanoma). B) To elucidate the molecular mechanisms by which TT2 interacts with nucleoside transport (effects on equilibrative and Na+-dependent transporters, bidirectional fluxes of purines and pyrimidines, competition with nucleoside transport probes), DNA (binding, intercalation, strand breakage and crosslinks, topoisomerase activities), and tumor cells (drug uptake/retention/catabolism, cell cycle analysis, caspase-8 and -3 activation, apoptosis, potentiation of antimetabolite action, and effectiveness in P-glycoprotein-positive and -negative multidrug-resistant (MDR) cells). C) To synthesize new TT2 analogs and screen them in vitro to clarify structure-activity relationships for drug uptake, nucleoside transport/DNA synthesis, DNA fragmentation, and cell growth/viability. Because inhibition of nucleoside transport is unusual among DNA-damaging quinone antitumor drugs, the use of bifunctional TT2 analogs with antileukemic activity in the nM range in vitro might provide a considerable advantage in polychemotherapy to potentiate the action of antimetabolites and sensitize MDR tumor cells.