Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences building Indian Institute of Technology Madras, Chennai, 600036, India.
Sci Rep. 2018 Aug 14;8(1):12138. doi: 10.1038/s41598-018-30691-4.
Gut microbiome plays an important role in determining the effectiveness of cancer therapy. The composition of the microbiome is crucial to maintain good digestive health in the host, and to prevent and treat colorectal cancers. Most cancer therapies employ oxidative stress, which disturbs the redox status of the cell, and consequently affect growth, reductive biosynthesis and cell death. Therefore, oxidative stress can undesirably affect the gut microbiome. Hence, it is important to understand the impact of oxidative stress on gut bacteria to devise effective treatment strategies. The current study induces oxidative stress in the model gut bacterium Enterococcus durans (MTCC 3031) with menadione and HO. Oxidative stress considerably decreased the redox ratio (NADPH/NADP), an indicator of the redox status, by 55% (menadione) and 28% (HO). In addition, an oxidative stress induced decrease in redox ratio decreased folate synthesis by the bacteria, which is an undesirable consequence for the host, since folate deficiency can induce colorectal cancer. Further, oxidative stress considerably decreased growth and the biomass density by 61% (menadione) and 21% (HO). Thus, maintenance of the cellular redox status and management of oxidative stress in the gut microbiome may be crucial to the effectiveness of cancer treatment strategies.
肠道微生物群在确定癌症治疗效果方面起着重要作用。微生物群的组成对于维持宿主良好的消化健康，预防和治疗结直肠癌至关重要。大多数癌症治疗方法采用氧化应激，这会扰乱细胞的氧化还原状态，从而影响生长、还原生物合成和细胞死亡。因此，氧化应激可能会对肠道微生物群产生不良影响。因此，了解氧化应激对肠道细菌的影响对于制定有效的治疗策略非常重要。本研究用亚甲二氢叶酸和 H2O2 诱导模型肠道细菌肠球菌（MTCC3031）产生氧化应激。氧化应激使氧化还原比（NADPH/NADP）显著降低了 55%（亚甲二氢叶酸）和 28%（H2O2），氧化还原比是氧化还原状态的一个指标。此外，氧化应激诱导的氧化还原比降低会降低细菌的叶酸合成，这对宿主来说是一个不利的后果，因为叶酸缺乏会诱导结直肠癌。此外，氧化应激使生长和生物量密度显著降低了 61%（亚甲二氢叶酸）和 21%（H2O2）。因此，维持细胞氧化还原状态和管理肠道微生物群中的氧化应激对于癌症治疗策略的有效性可能至关重要。
