Brim Hassan, Yooseph Shibu, Zoetendal Erwin G, Lee Edward, Torralbo Manolito, Laiyemo Adeyinka O, Shokrani Babak, Nelson Karen, Ashktorab Hassan
Department of Pathology, Department of Medicine and Cancer Center, Howard University, College of Medicine, Washington, District of Columbia, United States of America.
JCVI, San Diego, California, United States of America.
PLoS One. 2013 Dec 20;8(12):e81352. doi: 10.1371/journal.pone.0081352. eCollection 2013.
Colonic polyps are common tumors occurring in ~50% of Western populations with ~10% risk of malignant progression. Dietary agents have been considered the primary environmental exposure to promote colorectal cancer (CRC) development. However, the colonic mucosa is permanently in contact with the microbiota and its metabolic products including toxins that also have the potential to trigger oncogenic transformation.
To analyze fecal DNA for microbiota composition and functional potential in African Americans with pre-neoplastic lesions.
MATERIALS & METHODS: We analyzed the bacterial composition of stool samples from 6 healthy individuals and 6 patients with colon polyps using 16S ribosomal RNA-based phylogenetic microarray; the Human intestinal Tract Chip (HITChip) and 16S rRNA gene barcoded 454 pyrosequencing. The functional potential was determined by sequence-based metagenomics using 454 pyrosequencing.
Fecal microbiota profiling of samples from the healthy and polyp patients using both a phylogenetic microarraying (HITChip) and barcoded 454 pyrosequencing generated similar results. A distinction between both sets of samples was only obtained when the analysis was performed at the sub-genus level. Most of the species leading to the dissociation were from the Bacteroides group. The metagenomic analysis did not reveal major differences in bacterial gene prevalence/abundances between the two groups even when the analysis and comparisons were restricted to available Bacteroides genomes.
This study reveals that at the pre-neoplastic stages, there is a trend showing microbiota changes between healthy and colon polyp patients at the sub-genus level. These differences were not reflected at the genome/functions levels. Bacteria and associated functions within the Bacteroides group need to be further analyzed and dissected to pinpoint potential actors in the early colon oncogenic transformation in a large sample size.
结肠息肉是常见肿瘤，约50%的西方人群会出现，恶变风险约为10%。饮食因素被认为是促进结直肠癌（CRC）发生的主要环境暴露因素。然而，结肠黏膜始终与微生物群及其代谢产物（包括也有可能引发致癌转化的毒素）接触。
分析非裔美国人癌前病变患者粪便DNA中的微生物群组成和功能潜力。
我们使用基于16S核糖体RNA的系统发育微阵列（人类肠道芯片，HITChip）和16S rRNA基因条形码454焦磷酸测序技术，分析了6名健康个体和6名结肠息肉患者粪便样本中的细菌组成。通过基于序列的宏基因组学利用454焦磷酸测序技术确定功能潜力。
使用系统发育微阵列（HITChip）和条形码454焦磷酸测序技术对健康和息肉患者样本进行粪便微生物群分析，结果相似。只有在亚属水平进行分析时，两组样本之间才有区别。导致分离的大多数物种来自拟杆菌属。即使将分析和比较限于可用的拟杆菌基因组，宏基因组分析也未揭示两组之间细菌基因流行率/丰度的主要差异。
本研究表明，在癌前阶段，健康人和结肠息肉患者在亚属水平存在微生物群变化趋势。这些差异在基因组/功能水平未得到体现。需要进一步分析和剖析拟杆菌属内的细菌及其相关功能，以在大样本中确定早期结肠致癌转化的潜在因素。
