常见的实验室的科学家发现惊喜的抗癌特性的分子
![Incorporation of thymidine analogs into the human genome and removal of EdU by nucleotide excision repair. (<i>A</i>) Chemical structure of thymidine analogs used in this study. (<i>B</i>) Slot blot assay to test the reactivity of thymidine analogs with anti-BrdU antibody. HeLa cells were cultured either in regular medium or medium containing 10 μM thymidine analog (EdU, BrdU, CldU, IdU, F-ara-EdU, or AmdU) for 24 h. Genomic DNA was isolated, loaded onto a nitrocellulose membrane, and incubated with anti-BrdU or anti-ssDNA antibody. Anti-BrdU antibody recognizes BrdU, EdU, CldU, and IdU labeled genomic DNA. (<i>C</i>) Excision assay with anti-BrdU antibody immunoprecipitation. HeLa cells were treated with 10 μM thymidine analogs: EdU, BrdU, IdU, or CIdU for 24 h, then low-molecular-weight DNA was extracted by the Hirt procedure and immunoprecipitated with anti-BrdU antibodies. Purified, excised oligonucleotides were radiolabeled at the 3′ end together with a 50-mer as a spike-in internal control and separated on a DNA-sequencing gel along with a DNA ladder. (<i>D</i>) Removal of EdU requires excision repair. Human NHF1 wild-type and <i>XPA</i><sup>−/−</sup><i>XPC</i><sup>−/−</sup><i>CSB</i><sup>−/−</sup> mutant cells (knockout [KO]) were treated with or without 10 μM EdU for 24 h. Then, cells were lysed by the Hirt procedure, and low-molecular-weight DNA in the supernatant was immunoprecipitated with anti-BrdU antibodies. The oligonucleotides were mixed with a 50-mer internal control, 3′ end-labeled, and analyzed on a DNA-sequencing gel. EdU excision product is produced by the wild-type NHF1 cells but not by the excision repair defective <i>XPA</i><sup>−/−</sup><i>XPC</i><sup>−/−</sup><i>CSB</i><sup>−/−</sup> cell line. (<i>E</i>) In vivo excision assay with TFIIH antibody immunoprecipitation. HeLa cells were treated as in (<i>C</i>), and the primary excision products were isolated by TFIIH immunoprecipitation. Purified primary products were mixed with a 50-mer internal control oligonucleotide, 3′ end-radiolabeled, and separated on a DNA-sequencing gel along with a DNA ladder. The excised oligomers are 25 to 32 nt in length, as is the case in excision repair of bulky adducts. Low-molecular-weight excised oligomers are not observed in TFIIH IPs, because after the excision products are released from TFIIH, they are degraded, and as seen in (<i>C</i>) and (<i>D</i>), can be immunoprecipitated with anti-BrdU antibodies. Credit: <i>Proceedings of the National Academy of Sciences</i> (2022). DOI: 10.1073/pnas.2210176119 常见的实验室的科学家发现惊喜的抗癌特性的分子](https://scx1.b-cdn.net/csz/news/800a/2022/scientists-discover-su.jpg)
北卡罗来纳大学医学院的科学家们得出了一个惊人的发现,一个叫EdU的分子,这是常用的标签DNA实验室实验,实际上是被人类细胞DNA损伤,引发失控的过程最终致命影响细胞DNA修复,包括癌症细胞。
该发现发表在美国国家科学院院刊》上指出利用EdU的可能性的基础癌症治疗,鉴于其毒性和细胞快速分裂的选择性。
“EdU的意想不到的性质表明它将值得进行进一步研究的潜力,尤其是针对脑癌,”研究高级作者阿齐兹Sancar说,医学博士,博士,生物化学和生物物理学的莎拉·格雷厄姆该教授在北卡罗来纳大学医学院和UNC Lineberger综合癌症中心的成员。“我们想强调,这是一个基本而重要的科学发现。的科学界有很多工作要做,看看EdU可以成为武器对抗癌症。”
EdU (5-ethynyl-2′脱氧尿苷)本质上是一个受欢迎的科学工具在2008年首次合成作为模拟,或化学模拟,DNA构建块thymidine-which代表字母“T”的DNA编码中腺嘌呤(a)、胞嘧啶(C)、鸟嘌呤(G)和胸腺嘧啶(T)科学家添加EdU细胞实验室的实验在DNA取代胸苷。不像其他的胸苷类似物,它有一个方便的荧光探针分子的化学“处理”将紧密结合。因此可以相对轻松高效地用于标签和跟踪DNA,例如在DNA复制过程的研究细胞分裂。
自2008年以来,科学家们利用EdU以这种方式作为一种工具,在成千上万的研究发表。Sancar,谁赢得了2015年诺贝尔化学奖的DNA修复,就是这样一个科学家。当他的实验室开始使用EdU,他的团队意外发现EdU-labeled DNA引发DNA修复反应,即使这不是暴露于DNA有害,比如紫外线。
“这是非常震惊,”Sancar说。“所以我们决定进行进一步的探索研究。”
跟进奇怪的观察,研究团队发现EdU,原因仍然不清楚,改变DNA的方式引发修复反应核苷酸切除修复。这个过程涉及到的一小段替换受损的DNA和重新合成链。这是最修复的机制从紫外线伤害,香烟烟雾,DNA-altering化疗药物。研究人员绘制EdU-induced切除修复在高分辨率和发现它发生在整个基因组,它显然发生了一次又一次,因为每个新的修复链包括EdU,从而引发重新修复反应。
已经知道EdU适度对细胞有毒,但毒性的机制是一个谜。团队的发现强烈建议EdU杀死细胞诱导失控的徒劳的切除修复的过程,最终导致细胞通过程序性细胞死亡过程被称为凋亡自行终止。
这发现是有趣的,Sancar说,因为它表明,研究人员利用EdU DNA标签需要考虑其引发失控的切除修复。
“正如我们所说,也许成千上万的研究人员EdU研究DNA复制和使用细胞增殖在实验室实验中不知道人类细胞检测DNA损伤,”Sancar说。
Sancar和他的同事们也意识到EdU的属性可能会使大脑一种有效的抗癌药物的基础因为EdU成为纳入DNA只有在积极分裂细胞,然而,在大脑中,大多数非区分健康细胞。因此,原则上,EdU脑细胞快速分裂可以杀死癌细胞的同时,仍能保留非区分,健康的大脑细胞。
Sancar和他的团队希望寻求与其他研究人员调查EdU后续合作的属性作为抗癌剂。
“之前的研究已经发现证据表明EdU杀死癌细胞,包括大脑癌症细胞,但奇怪的是,从来没有人跟进的结果,”Sancar说。
进一步探索