UNG-initiated base excision repair is the major repair route for 5-fluorouracil in DNA, but 5-fluorouracil cytotoxicity depends mainly on RNA incorporation.
UNG-initiated base excision repair is the major repair route for 5-fluorouracil in DNA, but 5-fluorouracil cytotoxicity depends mainly on RNA incorporation.
复制标题
DOI：
10.1093/nar/gkr563
复制
发表时间：
2011-10
影响因子：
14.9
通讯作者：
Krokan HE
中科院分区：
文献类型：
--
作者：
Pettersen HS;Visnes T;Vågbø CB;Svaasand EK;Doseth B;Slupphaug G;Kavli B;Krokan HE
DNA 修复过程中 DNA 片段化导致的 5-氟尿嘧啶 (FU) 和 5-氟-2'-脱氧尿苷 (FdUrd) 的细胞毒性已被提议作为胸苷酸合酶 (TS) 抑制或 RNA 掺入影响的替代方案。本研究的目的是调查所提出的 5-氟嘧啶细胞毒性机制的相对贡献。我们证明，在人类癌细胞中，由尿嘧啶-DNA糖基化酶UNG启动的碱基切除修复（BER）是体外和体内FU-DNA修复的主要途径。 SMUG1、TDG 和 MBD4 在体外贡献不大，在体内检测不到。错配修复的贡献最多仅限于 FU:G 上下文。令人惊讶的是，个别尿嘧啶-DNA 糖基化酶或 MSH2 的敲低并不影响对 FU 或 FdUrd 的敏感性。 BER 或 DNA 损伤信号传导常见步骤的抑制剂影响对 FdUrd 和 HmdUrd 的敏感性，但不影响对 FU 的敏感性。为了支持主要由 RNA 介导的细胞毒性，FU 处理的细胞在 RNA 中积累的 FU 比 DNA 中多约 3000 至 15000 倍。此外，核糖核苷可以部分逆转 FU 的细胞毒性，但脱氧核糖核苷不能逆转，并且与 FdUrd 相比，FU 显示出适度的 TS 抑制作用。总之，UNG引发的BER是FU-DNA修复的主要途径，但FU的细胞毒性主要是RNA介导的，而DNA介导的作用仅限于FdUrd。
Cytotoxicity of 5-fluorouracil (FU) and 5-fluoro-2′-deoxyuridine (FdUrd) due to DNA fragmentation during DNA repair has been proposed as an alternative to effects from thymidylate synthase (TS) inhibition or RNA incorporation. The goal of the present study was to investigate the relative contribution of the proposed mechanisms for cytotoxicity of 5-fluoropyrimidines. We demonstrate that in human cancer cells, base excision repair (BER) initiated by the uracil–DNA glycosylase UNG is the major route for FU–DNA repair in vitro and in vivo. SMUG1, TDG and MBD4 contributed modestly in vitro and not detectably in vivo. Contribution from mismatch repair was limited to FU:G contexts at best. Surprisingly, knockdown of individual uracil–DNA glycosylases or MSH2 did not affect sensitivity to FU or FdUrd. Inhibitors of common steps of BER or DNA damage signalling affected sensitivity to FdUrd and HmdUrd, but not to FU. In support of predominantly RNA-mediated cytotoxicity, FU-treated cells accumulated ~3000- to 15 000-fold more FU in RNA than in DNA. Moreover, FU-cytotoxicity was partially reversed by ribonucleosides, but not deoxyribonucleosides and FU displayed modest TS-inhibition compared to FdUrd. In conclusion, UNG-initiated BER is the major route for FU–DNA repair, but cytotoxicity of FU is predominantly RNA-mediated, while DNA-mediated effects are limited to FdUrd.
登录
查看更多内容
影响因子：
4.5
作者：
Gustavsson, Marie;Ronne, Hans
通讯作者：
Ronne, Hans
影响因子：
4.7
作者：
Andersen, S;Heine, T;Nilsen, H
通讯作者：
Nilsen, H
影响因子：
4.8
作者：
Doseth, Berit;Visnes, Torkild;Kavli, Bodil
通讯作者：
Kavli, Bodil
影响因子：
4.8
作者：
Boorstein, RJ;Cummings, A;Teebor, GW
通讯作者：
Teebor, GW
影响因子：
2.9
作者：
Grogan BC;Parker JB;Guminski AF;Stivers JT
通讯作者：
Stivers JT