Advancing the Biosynthetic and Chemical Understanding of the Carcinogenic Risk Factor Colibactin and Its Producers
Advancing the Biosynthetic and Chemical Understanding of the Carcinogenic Risk Factor Colibactin and Its Producers
复制标题
DOI：
10.1021/acs.biochem.2c00229
复制
发表时间：
2022-06-20
期刊：
影响因子：
2.9
通讯作者：
Watanabe, Kenji
中科院分区：
文献类型：
--
作者：
Hirayama, Yuichiro;Sato, Michio;Watanabe, Kenji
近期研究表明，大肠杆菌常常携带一个生物合成基因簇，被称为pks岛或clb簇，该基因簇能产生一种具有基因毒性的聚酮化合物 - 非核糖体肽杂合次生代谢产物，称为大肠杆菌素。虽然该基因簇并不总是表达，但当存在于结肠中的菌株产生这种基因毒素时，它被怀疑成为结直肠癌的一个风险因素。因此，人们非常有兴趣设计一种简单的方法来检测产生大肠杆菌素的菌株，并了解大肠杆菌素如何诱发肿瘤发生的详细机制，以开发便捷的早期筛查方法以及可能的针对结直肠癌的预防性治疗方法。然而，直到最近，大肠杆菌素的确切化学结构仍然难以捉摸，这主要是由于其产量低且不稳定。在这篇综述中，我们将简要追溯近期导致活性完整大肠杆菌素结构鉴定的研究。随后，我们将描述我们为开发检测大肠杆菌素产生菌的简单方法所做的努力，我们基于常规聚合酶链反应和环介导等温扩增技术建立了一些方法。我们还设计了一种基于活性的荧光探针，用于检测产生大肠杆菌素的菌株，该探针能够区分所筛选的大肠杆菌菌株中的大肠杆菌素产生水平。利用该探针，我们从一个结直肠癌组织样本中分离出一株野生型高产大肠杆菌素的菌株，这株菌株在鉴定新的大肠杆菌素代谢产物以及通过核磁共振对其进行结构表征方面被证明是有价值的。这些技术以及它们所提供的化学见解应该会改善对结直肠癌的防治。
Recent studies have shown that Escherichia coli often carries a biosynthetic gene cluster termed either the pks island or the clb cluster that allows the production of a genotoxic polyketide-nonribosomal peptide hybrid secondary metabolite called colibactin. While the gene cluster is not always expressed, when the strain that resides in the colon produces the genotoxin, it is suspected to become a risk factor for colorectal cancer. Therefore, there is great interest in devising a simple method for the detection of colibactin-producing strains and understanding the detailed mechanism of how colibactin can induce oncogenesis, to develop convenient early screening methods and possible preventive treatments against colorectal cancer. However, the definitive chemical structure of colibactin remained elusive until recently, primarily due to its low yield and instability. In this review, we will briefly trace the recent studies leading to the identification of the structure of the active intact colibactin. Subsequently, we will describe our efforts toward developing simple methods for detecting colibactin producers, where we established methods based on the conventional polymerase chain reaction and loop-mediated isothermal amplification techniques. We also designed an activity-based fluorogenic probe for detecting colibactin-producing strains that could discern colibactin production levels among the E. coli strains screened. Using the probe, we isolated a wild-type high-colibactin-producing strain from a colorectal cancer tissue sample that proved to be valuable in identifying new colibactin metabolites and structurally characterizing them by nuclear magnetic resonance. Those techniques and the chemical insight they furnished should improve the fight against colorectal cancer.