微生物基因毒素colibactin在结直肠瘤中加剧了不匹配修复突变
Michael W Dougherty1, Rafael Valdés-Mas2, Kevin M Wernke3
1Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA.
概括
生产可利巴克的大肠杆菌通过导致DNA损伤和增加特定突变来促进结直肠癌 (CRC). 这项研究揭示了菌素暴露如何加剧CRC中不匹配修复缺陷 (MMRd) 突变,突出了潜在的治疗点.
科学领域:
- 微生物学 微生物学
- 遗传学 遗传学 是一个
- 在瘤学瘤学.
背景情况:
- 包括大肠杆菌在内的某些Enterobacteriaceae菌株具有负责合成大肠杆菌素的pks基因集群.
- 生产可利巴克的大肠杆菌与结直肠癌 (CRC) 的促进有关,并在体外诱导一种特定的突变特征,也在人类CRC基因组中观察到.
- 菌素暴露对CRC突变格局的体内影响仍然不完全理解.
研究的目的:
- 在体内调查 colibactin 暴露对结直肠癌 (CRC) 突变格局的影响.
- 阐明宿主对 colibactin 的基因毒性活动的反应机制.
- 为了探索与胆固醇菌素相关突变和人类CRC的不匹配修复缺陷 (MMRd) 之间的关联.
主要方法:
- 对暴露于产生大肠杆菌素的小鼠中的结肠瘤进行比较分析,与缺乏大肠杆菌素的大肠杆菌相比.
- 在体外研究使用合成胆固醇菌素 (742) 和非活性类比物 (746) 对人类结肠上皮细胞和MMRd结肠癌细胞 (HCT 116) 的实验.
- 全球转录基因分析,以识别对 colibactin 暴露的反应上调调的途径.
- 对大量人类CRC患者队列 (n=2,945) 的分析,以评估特定突变特征的同时发生.
主要成果:
- 在小鼠中,产生可利巴克的大肠杆菌驱动瘤表现出较高的单基替代 (SBS) 负担,其中较大比例归因于不匹配修复缺陷 (MMRd;SBS15).
- 合成大肠杆菌素诱导了DNA损伤,并激活了人体结肠细胞中的p53和衰老通路.
- 在MMRd结肠癌细胞中,慢性大肠杆菌素暴露导致了BRCA1,Fanconi贫血和MMR信号通路的上调,同时增加了SBS特征 (SBS88,SBS17,SBS44).
- 在人类CRC患者中,在MMRd SBS44和pks相关的SBS88特征之间观察到显著的同时发生和正相关性.
结论:
- 科利巴克暴露会导致DNA损伤,并影响宿主反应途径,包括与DNA修复和衰老相关的途径.
- 科利巴克丁可能会加剧结直肠癌中MMRd相关的突变.
- 这些发现揭示了 colibactin 对基因毒性的潜在宿主反应机制,并表明在CRC进展中可能发挥作用,特别是在MMRd环境中.
相关概念视频
Mismatch Repair
4.9K
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
4.9K
Drugs that Destabilize Microtubules
2.0K
Microtubules are dynamic structures and can be regulated by microtubule targeting agents (MTAs). Microtubule destabilizing drugs are a class of MTAs that destabilize and prevent microtubules' polymerization. Both natural and synthetic chemicals can be found under this class of drugs. Vincristine and vinblastine, two vinca alkaloids, and colchicine were among the first to be discovered. These drugs can affect cells in various ways, either by inducing a change in cell morphology, preventing...
2.0K
Nucleotide Excision Repair
37.3K
Overview
37.3K
Other Unique Bacteria
35
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic...
35
Mutagenicity and Carcinogenicity
1.3K
Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...
1.3K
Mutations in Microorganisms
32
Mutations are heritable changes in an organism’s genome involving alterations in the base sequence of DNA or RNA. These changes can influence cellular processes and phenotypic traits, potentially transforming the unaltered wild type into a mutant form. Such changes, termed forward mutations, are pivotal in shaping the genetic diversity of organisms.RNA viruses exhibit the highest mutation rates due to the absence of robust proofreading mechanisms during genome replication. In contrast,...
32


