Effect Of First-line Chemotherapy On Intestinal Microflora In Patients With Lung Cancer

ObjectiveIn this study,16 S rRNA sequencing of intestinal microorganisms in fecal samples was used to analyze the changes of intestinal flora,differential bacteria and speculated metabolic function in patients with lung cancer before and after first line chemotherapy.The purpose of this study is to provide evidence for improving the efficacy of chemotherapy and the feasibility of further treatment.Methods1.Patient enrollment and information collection26 patients who met the inclusion criteria with primary lung cancer diagnosed by pathology in Anhui Provincial Cancer Hospital from February 2019 to July 2019 were selected and their clinical data were collected and recorded.2.Experimental methods and data analysis(1)Specimen collection,Fresh stool samples were collected before the first chemotherapy and after the second cycle of chemotherapy.After collection,the samples were placed in a-80°C environment and frozen until sequencing.(2)DNA extraction,The whole genome DNA of each sample was extracted by the SDS method,then detected the purity and integrity by 1% agarose electrophoresis.(3)Gene sequencing,The Illumina Mi Seq high-throughput sequencing platform was used to sequence the 16 S rRNA gene.(4)Data analysis,QIIME 2.0 was used to process sequencing data and analyzed the richness or diversity of intestinal microbes.The functional characteristics of the gut microbiota were predicted by PICRUSt.Results1.The difference of the structure of intestinal flora in patients with lung cancer before and after chemotherapy(1)Analysis of intestinal microbial richness and diversity in patients with lung cancer before and after chemotherapy.The abundance of intestinal bacteria before chemotherapy was higher than that after chemotherapy,but there was no statistically significant difference in the diversity(P≥0.05).(2)Differences of intestinal microbial community structure between the two groupsBeta diversity analysis was performed for the two groups.Based on Bray Curtis distance analysis,there was no statistically significant difference between the chemotherapy after group(CAG)and chemotherapy before group(CBG)(P≥0.05).The analysis results based on Unweighted Unifrac and Weighted Unifrac showed statistically significant differences between CAG and CBG(P<0.05).(3)Analysis of intestinal microbial composition and differences between the two groupsSix genera had statistically significant differences in the genus level(P <0.05,LDA score>2.0).Compared with the CAG,the relative abundance of Faecalibacterium,Oscillospira,and Alistipes in CBG were significantly higher,while the relative abundance of Veillonella,Streptococcus,f＿Christensenellaceae＿uncl in the CAG were significantly higher than that in the CBG(P<0.05).2.Prediction of intestinal microbial metabolic function in lung cancer patients before and after chemotherapy Analysis of intestinal microbial function or metabolicIn the KEGG signaling pathway,the lung cancer samples in CAG were significantly enriched in the phosphotransferase system,C5-branched dibasic acid metabolism,dioxin degradation,caprolactam degradation,ABC transporter,fatty acid metabolism,ascorbic acid and aldehyde acid metabolism,Two-component signaling system,ubiquinone and other terpene quinone compounds,tryptophan metabolism,tyrosine metabolism,aminobenzoic acid degradation,glycolysis,spliceosome and glycerophosphate metabolism.The lung cancer samples in CBG was significantly enriched in six pathways,including protein digestion and absorption,zeatin biosynthesis,carbon pool composed of folic acid,RNA polymerase,glycosaminoglycan degradation,and other polysaccharide degradation.(P <0.05).Conclusion1.The number of pathogenic bacteria in the intestinal condition of lung cancer patients were increased after they received chemotherapy.While the butyrate-producing bacteria decreased.It indicates that chemotherapy is not easy to recover the intestinal mucosa damage and the intestinal barrier function decreases.2.The intestinal flora structure of lung cancer patients changed after chemotherapy,which led to metabolic disorder.Meanwhile,fatty acid metabolism,tryptophan metabolism,tyrosine metabolism,glycolysis function up-regulated,protein digestion and absorption and RNA polymerase function were down-regulated.3.The structure of the intestinal flora changed,meanwhile,causing metabolic disorders,fatty acid metabolism,tryptophan metabolism,tyrosine metabolism,glycolysis function up-regulated,protein digestion and absorption,RNA polymerase function down-regulated,in lung cancer patients who received chemotherapy.