Dataset Information

Methylome Changes During the Progression of Colitis-accelerated Colon Cancer in Mouse and the Blockage by Curcumin

ABSTRACT: Inflammation is highly associated with colon carcinogenesis. Epigenetic mechanisms play an important role in the initiation and progression of colon cancer. Curcumin is a dietary cancer preventive phytochemical with promising effect in suppressing colitis-associated colon cancer (CAC) in azoxymethane (AOM) and dextran sulfate sodium (DSS) mouse model. In the present study, we confirmed the effect of curcumin in suppressing colon cancer. Using Agilent SureSelect Methyl-seq and RNA-seq, we obtained single-base methylation profile and transcriptome analyses of epithelial cells from control group, AOM and DSS induced group (AOM+DSS), and AOM and DSS induced plus curcumin treated group (AOM+DSS+Curcumin) in a 18 weeks long-term colon cancer mouse model. The average DNA methylation levels of the three groups are significantly different also. Based on differential methylation patterns of three groups, several pathways of genes were identified including IL-8 signaling, LPS-stimulated MAPK signaling and colorectal cancer metastasis signaling. Among these methylated pathways and genes, Tnf, an inflammatory gene stood out with decreased DNA CpG methylation in the AOM-DSS as compared to the control group and interestingly curcumin reversed the CpG methylation (validated by pyrosequencing). The functional role of DNA methylation of Tnf was confirmed by in vitro luciferase transcriptional activity assay. In addition, we found that a group of genes associated with the inflammatory responses and their methylation level was decreased in AOM+DSS group but restored in the curcumin treated group. Taken together, in this study, aberrant DNA CpG methylation of the inflammatory response was found in colitis-associated colon cancer and curcumin restored their CpG methlyation, which could potentially explain the inflammatory and cancer protective effects of curcumin. (Note this GEO/dataset is the DNA methyl-seq part of the study.)

ORGANISM(S): Mus musculus

PROVIDER: GSE102645 | GEO | 2018/06/11

REPOSITORIES: GEO

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Project description:Inflammation is highly associated with colon carcinogenesis. Epigenetic mechanisms play an important role in the initiation and progression of colon cancer. Curcumin is a dietary cancer preventive phytochemical with promising effect in suppressing colitis-associated colon cancer (CAC) in azoxymethane (AOM) and dextran sulfate sodium (DSS) mouse model. In the present study, we confirmed the effect of curcumin in suppressing colon cancer. Using Agilent SureSelect Methyl-seq and RNA-seq, we obtained single-base methylation profile and transcriptome analyses of epithelial cells from control group, AOM and DSS induced group (AOM+DSS), and AOM and DSS induced plus curcumin treated group (AOM+DSS+Curcumin) in a 18 weeks long-term colon cancer mouse model. We observed differentially expressed genes in pair-wise comparison and identified several pathways of small set of genes involved in the potential preventive effect of curcumin. These pathways include LPS/IL-1 mediated inhibition of RXR function, NRF2-mediated oxidative stress response, aldosterone signaling in epithelial cells, production of NO and ROS in macrophages, and IL-6 signaling. The average DNA methylation levels of the three groups are significantly different also. Based on differential methylation patterns of three groups, several pathways of genes were identified including IL-8 signaling, LPS-stimulated MAPK signaling and colorectal cancer metastasis signaling. Among these methylated pathways and genes, Tnf, an inflammatory gene stood out with decreased DNA CpG methylation in the AOM-DSS as compared to the control group and interestingly curcumin reversed the CpG methylation (validated by pyrosequencing). These observations correlated with decreased, and increased with curcumin, Tnf expression in RNA-seq (validated by qPCR), respectively. The functional role of DNA methylation of Tnf was confirmed by in vitro luciferase transcriptional activity assay. In addition, we found that a group of genes associated with the inflammatory responses and their methylation level was decreased in AOM+DSS group but restored in the curcumin treated group. Taken together, in this study, aberrant DNA CpG methylation of the inflammatory response was found in colitis-associated colon cancer and curcumin restored their CpG methlyation, which could potentially explain the inflammatory and cancer protective effects of curcumin. (Note this GEO/dataset is the RNA-seq part of the study.)

Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study are using transcriptome profiling (RNA-seq) to evaluate the effects of anti-S100a9 antibody on the global transcriptome of the colon tissues of the AOM/DSS mouse model (a model that mimics the human colitis-associated colon cancer development). Methods: 36 five-week-old male ICR mice were randomized divided into three groups: control (i.e. no AOM/DSS and antibody treatment), AOM/DSS+IgG Ab (1.5 mg/kg), and AOM/DSS+anti-S100a9 Ab (1.5 mg/kg). Mice were intraperitoneal injected with a single dose of 10 mg/kg azoxymethane (AOM) (A5486; Sigma) on day 1. One week after the AOM injection, mice were given three cycles of DSS (cycle 1: 2%, 7 days; cycle 2: 1.5%, 5 days; and cycle 3: 1.5%, 5 days, DSS: 36–50 kDa; MP Biomedicals, CA, USA) in their drinking water, and then distilled water until the end of the experiment. Antibodies were administrated intravenously every two days during the three cycles of DSS treatment. Mice were sequentially killed randomly at the end of the 18th week, and at least five mice were killed for each group at each time point. RNAs were extracted by Trizol and sequenced by Solexa high-throughput sequencing service (Oebiotech, Shanghai, China). Data were extracted and normalized according to the manufacturer’s standard protocol.Each group has three mices' colon tissues be tested. Results: Log-fold changes of up- or down-regulated mRNAs between the control and experiment group were selected with a significance threshold of p<0.05. There are 1017 mRNAs were up-regulated and 815 were down-regulated in “AOM/DSS+IgG Ab" group comparing to “control" group. There are 385 mRNAs were up-regulated and 163 were down-regulated in “AOM/DSS+anti-S100a9 Ab" group comparing to “control" group. There are 1314 mRNAs were up-regulated and 968 were down-regulated in “AOM/DSS+anti-S100a9 Ab" group comparing to “AOM/DSS+IgG Ab". Conclusions: Our study describes the global transciptome changes of colon tissues of the AOM/DSS mouse model induced by anti-S100a9 antibody treatment.

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Methylome Changes During the Progression of Colitis-accelerated Colon Cancer in Mouse and the Blockage by Curcumin

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