In vitro and in vivo evaluation of novel antitumor prodrugs of 5-fluoro-2'-deoxyuridine activated by hypoxic irradiation
In vitro and in vivo evaluation of novel antitumor prodrugs of 5-fluoro-2'-deoxyuridine activated by hypoxic irradiation
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DOI：
10.1016/j.ijrobp.2003.09.048
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发表时间：
2004-02-01
影响因子：
7
通讯作者：
Nishimoto, SI
中科院分区：
文献类型：
--
作者：
Shibamoto, Y;Tachi, Y;Nishimoto, SI
目的：我们以前开发了一种新的抗肿瘤前药，其在5-氟尿嘧啶（5-FU）的N（1）位上具有2-氧代丙基取代基，并通过低氧照射的单电子还原释放5-FU。虽然该化合物在体内有效，但其对小鼠肿瘤的活性不足以保证临床研究。因此，我们开发了一个类似的5-氟-2 '-脱氧尿苷（FdUrd），这是一般比5-FU更有效的辐射活化的前药家族，并研究了它们的辐射化学反应性和在体外和体内effects.Methods和材料：在FdUrd的N（3）位上带有各种2-氧代烷基取代基的化合物合成和研究。溶解在水或培养基中的前药在有氧或低氧照射后，使用高效液相色谱法测量FdUrd的释放。为了研究体外细胞毒性，在有氧或低氧条件下，在前药存在下照射培养物中的SCCVII和EMT 6细胞，然后与化合物一起保持24小时。然后使用集落测定测量细胞存活。为了研究体内效应，在照射前30分钟将药物以100或300 mg/kg的剂量腹膜内注射到携带EMT 6肿瘤的Balb/c小鼠中。然后评估肿瘤生长延迟时间。结果如下：在体外，前药在低氧照射后以1.6-2.0 X 10（-7）mol/J的G值（由1 J的辐射能量产生的分子的摩尔数）释放FdUrd。FdUrd释放与低氧照射的G-值约100倍以上的有氧照射。在所测试的前药中，带有2-氧代环戊基取代基的OFU 106在培养基中释放最高量的FdUrd，并对其进行进一步的体外和体内测定。尽管单独施用的OFU 106在高达0.2mM的浓度下没有显示出细胞毒性，但是当在低氧照射之前施用并与细胞保持24小时时，其产生增强的细胞毒性效应。在存活分数为1%时计算的增强比在0.04 mM时为1.35-1.4，在0.2 mM时为1.45-1.5。与单独接受20戈伊辐射相比，在接受20戈伊辐射前给予（100或300 mg/kg）并未产生明显的生长延迟。结论：在体外低氧照射，FdUrd的前药被有效地激活为5-FU的前药，但不能检测到显着的体内效应。这种前体药物设计的策略应用于进一步开发更有效的抗癌剂的辐射活化前体药物。(C)2004年爱思唯尔公司
Purpose: We previously developed a novel antitumor prodrug that has a 2-oxopropyl substituent at the N(1) position of 5-fluorouracil (5-FU) and releases 5-FU via one-electron reduction on hypoxic irradiation. Although the compound was effective in vivo, its activity against murine tumors was not high enough to warrant clinical studies. Therefore, we developed a similar family of radiation-activated prodrugs of 5-fluoro-2'-deoxyuridine (FdUrd), which is generally more potent than 5-FU, and investigated their radiation chemical reactivity and in vitro and in vivo effects.Methods and Materials: Compounds bearing various 2-oxoalkyl substituents at the N(3) position of FdUrd were synthesized and investigated. After aerobic or hypoxic irradiation to the prodrugs dissolved in water or culture medium, release of FdUrd was measured using high-performance liquid chromatography. To investigate in vitro cytotoxicity, SCCVII and EMT6 cells in culture were irradiated in the presence of the prodrug under aerobic or hypoxic conditions, and then kept with the compound for 24 h. Cell survival was then measured using a colony assay. To investigate in vivo effects, the drug was injected intraperitoneally at a dose of 100 or 300 mg/kg into Balb/c mice bearing EMT6 tumors 30 min before irradiation. The tumor growth delay-time was then assessed. Results: In vitro, the prodrugs released FdUrd at G-values (molar numbers of molecules produced by 1 J of radiation energy) of 1.6-2.0 X 10(-7) mol/J after hypoxic irradiation. The G-values for FdUrd release with hypoxic irradiation were about 100-fold greater than those with aerobic irradiation. Among the prodrugs tested, OFU106 bearing a 2-oxocyclopentyl substituent released the highest amount of FdUrd in the culture medium, and it was subjected to further in vitro and in vivo assays. Although OFU106 administered alone showed no cytotoxicity up to a concentration of 0.2 mM, it produced an enhanced cytotoxic effect when administered before hypoxic irradiation and kept with the cells for 24 h. The enhancement ratios calculated at the surviving fraction of 1% were 1.35-1.4 at 0.04 mM and 1.45-1.5 at 0.2 mM. In vivo, however, administration of OFU106 (100 or 300 mg/kg) before 20 Gy of irradiation did not produce marked growth delays compared with 20 Gy of radiation alone.Conclusion: On hypoxic irradiation in vitro, the prodrugs of FdUrd were activated as efficiently as were the prodrugs of 5-FU, but marked in vivo effects could not be detected. This strategy of prodrug design should be used in further development of radiation-activated prodrugs of more potent anticancer agents. (C) 2004 Elsevier Inc.