Résumé
Objective@#To explore the interaction of multi-target stool DNA (MT-sDNA), intestinal flora and environmental factors in the development of colorectal cancer, so as to provide insights into pathogenesis study of colorectal cancer.@*Methods@#A total of 54 cases of colorectal cancer from the First Affiliated Hospital of Ningbo University were included in the case group and 51 healthy subjects were included in the control group. Demographic information, diet and family history of colorectal cancer were collected by a questionnaire survey. MT-sDNA, intestinal flora, cancer antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) and other tumor markers were detected. Interactions of MT-sDNA, intestinal flora and environmental factors with the development of colorectal cancer was analyzed by multifactor dimensionality reduction (MDR), crossover analysis and additive model.@*Results@#The case group included 20 males (37.04%) and 34 females (62.96%), and had a mean age of (64.89±9.72) years. The control group included 24 males (47.06%) and 27 females (52.94%), and had a mean age of (53.94±10.33) years. MDR analysis showed that subjects with both high absolute intestinal flora indexes and positive MT-sDNA had an increased risk of colorectal cancer (OR=3.782, 95%CI: 1.190-5.034). Crossover analysis showed that subjects with positive MT-sDNA and >5 μg/L of CEA had an increased risk of colorectal cancer (OR=2.121, 95%CI: 1.162-4.033). Additive model analysis showed that MT-sDNA had positive additive interaction with CEA (SI=3.687, 95%CI: 1.229-7.238), and MT-sDNA had negative additive interaction with fruit intake (SI=0.145, 95%CI: 0.020-0.753).@*Conclusion@#Positive MT-sDNA can synergistically increase the risk of colorectal cancer with high intestinal flora index and CEA, and fruit intake can reduce the risk of colorectal cancer in MT-sDNA-positive population.
Résumé
The effects of epigenetic modification on the differentiation of islet cells and the expression of associated genes (Pdx-l,Pax4,MafA,and Nkx6.1,etc) were investigated.The promoter methylation status of islet differentiation-associated genes (Pdx-1,Pax4,MafA and Nkx6.1),Oct4 and MLH1 genes of mouse embryonic stem cells,NIH3T3 cells and NIT-1 cells were profiled by methylated DNA immunoprecipitation,real-time quantitative PCR (MeDIP-qPCR) techniques.The histone modification status of these genes promoter region in different cell types was also measured by using chromatin immunoprecipitation real-time quantitative PCR methods.The expression of these genes in these cells was detected by using real-time quantitative PCR.The relationship between the epigenetic modification (DNA methylation,H3 acetylation,H3K4m3 and H3K9m3) of these genes and their expression was analyzed.The results showed that:(1) the transcription-initiation-sites of Pdx-1,MafA and Nkx6.1 were highly methylated in NIH3T3 cells; (2) NIH3T3 cells showed a significantly higher level of DNA methylation modification in the transcription-initiation-site of Pdx-1,Pax4,MafA and Nkx6.1 genes than that in mES cells and NIT-1 cells (P＜0.05); (3) NIT-1 cells had a significantly higher level of H3K4m3 modification in the transcription-initiation-site of Pdx-1,Pax4,MafA and Nkx6.1 genes than that in mES cells and NIH3T3 cells (P＜0.05),with significantly increased level of gene expression; (4) NIH3T3 cell had a significantly higher level of H3K9m3 modification in the transcription-initiation-site of Pdx-1,Pax4,MafA and Nkx6.1 genes than that in mES cells and with NIT-1 cell (P＜0.05),with no detectable mRNA expression of these genes.It was concluded that histone modification (H3K4m3 and H3K9m3) and DNA methylation might have an intimate communication between each other in the differentiation process from embryonic stem cells into islet cells.