School of Life Sciences, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, USA.
Institute for Cancer Research, Shiraz University of Medical Sciences, Zand street, Shiraz 71348, Iran.
FEMS Microbiol Ecol. 2018 Aug 1;94(8). doi: 10.1093/femsec/fiy120.
Inflammation contributes to colon cancer initiation. The disease along with allergy and autoimmunity has been on the rise in Western and more recently in developing countries. This shared rise may imply a shared cause. Streptomycetes are known as soil residents and produce numerous antiproliferative, anti-inflammatory/immunosuppressive compounds, e.g. rapamycin and tacrolimus. Recently, Streptomyces has been shown in gut microbiome with a lower prevalence in humans than nonhumans whose microbiomes might be more representative of past humans' in a hunter-gatherer and farming environment. It was previously suggested that Streptomyces producing antiproliferatives/immunosuppressants would be 'old friends' against allergy and autoimmunity as well as inflammatory bowel diseases. Here, it is suggested that these streptomycetes within gut microbiome have also been evolved as 'old friends' to suppress colon tumorigenesis through their numerous antiproliferatives/immunosuppressants. Subsequently, the shortage of exposure to nature in our current lifestyle has cost us the shortage of these friends and vulnerability to colon cancer. An attractive research area in the future would be whether the shortage of Streptomyces exposure can be the underlying reason for colon cancer, allergy and autoimmunity rise, and if the restoration of these 'old friends' through probiotics or more exposure to nature can prevent colon cancer.
炎症促进结肠癌的发生。这种疾病与过敏和自身免疫性疾病一起，在西方国家以及最近在发展中国家呈上升趋势。这种共同的上升趋势可能意味着存在共同的原因。链霉菌被称为土壤居民，它们产生许多抗增殖、抗炎/免疫抑制化合物，例如雷帕霉素和他克莫司。最近，在肠道微生物组中发现了链霉菌，其在人类中的流行程度低于非人类，而非人类的微生物组可能更能代表过去人类在狩猎采集和农业环境中的情况。此前有人提出，产生抗增殖/免疫抑制剂的链霉菌将成为过敏和自身免疫以及炎症性肠病的“老朋友”。在这里，我们认为肠道微生物组中的这些链霉菌也已经进化为“老朋友”，通过其众多的抗增殖/免疫抑制剂来抑制结肠癌的发生。因此，我们目前的生活方式中缺乏接触大自然的机会，使我们失去了这些朋友，从而更容易患上结肠癌。未来一个有吸引力的研究领域是，接触链霉菌的机会减少是否是结肠癌、过敏和自身免疫性疾病上升的根本原因，以及通过益生菌或更多地接触大自然来恢复这些“老朋友”是否可以预防结肠癌。
