RESUMO
Gut microbiome sequencing studies have great potential to translate microbial analysis outcomes into human health research. Sequencing strategies of 16S amplicon and whole-metagenome shotgun (WMS) are two main methods in microbiome research with respective advantages. However, how sample heterogeneity, sequencers and library preparation protocols affect the sequencing reproducibility of gut microbiome needs further investigation. This study aims to provide a reference for the selection of sequencing technologies by comparing differences in microbial composition from different sampling sites. The results of three widely adopted sequencers showed that the technical repetition correlation (r= 0. 94) was high in WMS method, while the biological repetition correlation (r = 0. 69) was low. Bray-Curtis distance identified that dissimilarity from biological replicates was larger than that of technical replicates (P<0. 001). In addition, dissimilarity and specific taxonomic profiles were observed between 16S and WMS datasets. Our results imply that homogenization is a necessary step before sample DNA extraction. The sequencers contributed less to taxonomic variation than the library preparation protocols. We developed an empirical Bayes approach that " borrowed information" in calculations and analyzed batch effect parameters using standardized data and prior distributions of (non-) parameters, which may improve population comparability between 16S and WMS and provide a basis for further application to fusion analysis of published 16S and microbial datasets.
RESUMO
N6-methyladenosine (m6A) modification has been reported as a critical regulator of gene transcript expression. Although m6A modification plays important roles in tumor development, its role in therapeutic resistance remains unknown. In this study, we aimed to examine the expression level of m6A-modification related proteins and elucidate the effect of m6A-related proteins on radiation response in nasopharyngeal carcinoma (NPC). Among the genes that participated in m6A modification, YTHDC2, a m6A reader, was found to be consistently highly expressed in radioresistant NPC cells. Knocking down of YTHDC2 expression in radioresistant NPC cells improved the therapeutic effect of radiotherapy in vitro and in vivo, whereas overexpression of YTHDC2 in radiosensitive NPC cells exerted an opposite effect. Bioinformatics and mechanistic studies revealed that YTHDC2 could physically bound to insulin-like growth factor 1 receptor (IGF1R) messenger RNA and promoted translation initiation of IGF1R mRNA, which in turn activated the IGF1R-AKT/S6 signaling pathway. Thus, the present study suggests that YTHDC2 promotes radiotherapy resistance of NPC cells by activating the IGF1R/ATK/S6 signaling axis and may serve as a potential therapeutic target in radiosensitization of NPC cells.
