title: Tumor grafting induces changes of gut microbiota in athymic nude mice in the presence and absence of medicinal Gynostemma saponins.
abstract: Recent findings have revealed that gut microbiota plays a substantial role in modulating diseases such as autism, rheumatoid arthritis, allergies, and cancer that occur at sites distant to the gut. Athymic nude mice have been employed for tumorigenic research for decades; however, the relationships between the gut microbiome and host's response in drug treatment to the grafted tumors have not been explored. In this study, we analyzed the fecal microbiome of nonxenograft and xenograft nude mice treated with phytosaponins from a popular medicinal plant, Gynostemma pentaphyllum (Gp). Analysis of enterobacterial repetitive intergenic consensus (ERIC)-PCR data showed that the microbiota profile of xenograft mice departed from that of the nonxenograft mice. After ten days of treatment with Gp saponins (GpS), the microbiota of the treated mice was closer to the microbiota at Day 0 before the implantation of the tumor. Data obtained from 16S pyrosequencing of fecal samples reiterates the differences in microbiome between the nonxenograft and xenograft mice. GpS markedly increased the relative abundance of Clostridium cocleatum and Bacteroides acidifaciens, for which the beneficial effects on the host have been well documented. This study, for the first time, characterizes the properties of gut microbiome in nude mice responding to tumor implant and drug treatment. We also demonstrate that dietary saponins such as GpS can potentially regulate the gut microbial ecosystem by increasing the number of symbionts. Interestingly, this regulation of the gut ecosystem might, at least in part, be responsible for or contribute to the anticancer effect of GpS.
authors.affiliation: Center for Cancer & Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Center for Cancer & Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong, China.
authors.forename: William C S
authors.initials: WC
authors.lastname: Tai
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
authors.forename: Manreetpal S
authors.initials: MS
authors.lastname: Brar
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
authors.forename: Frederick C C
authors.initials: FC
authors.lastname: Leung
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China; Center for Cancer & Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong, China.
authors.forename: W L Wendy
authors.initials: WL
authors.lastname: Hsiao
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D005243:Feces / Q000382:microbiology; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D029774:Gynostemma / Q000737:chemistry*; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010946:Plants, Medicinal / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats; D012503:Saponins / Q000494:pharmacology*; D017423:Sequence Analysis, RNA; D023041:Xenograft Model Antitumor Assays
chemical_list: D012336:RNA, Ribosomal, 16S; D012503:Saponins