ABSTRACT: Persistent microRNA-gene networks in primary human hepatocytes upon withdrawal of aflatoxin B1 exposure are related to hepatocellular carcinoma [miRNA]
Project description:Persistent microRNA-gene networks in primary human hepatocytes upon withdrawal of aflatoxin B1 exposure are related to hepatocellular carcinoma
Project description:Persistent microRNA-gene networks in primary human hepatocytes upon withdrawal of aflatoxin B1 exposure are related to hepatocellular carcinoma [mRNA]
Project description:Hepatocellular carcinoma (HCC), one of the most common cancer types, is a multi-factorial disease. One strongly associated factor is oral exposure to the food-contaminant aflatoxin B1 (AFB1). A clear link between AFB1-induced p53 mutations and HCC exists, however less is known about the association with microRNA expression changes. In particular, irreversible adverse effects that may occur at the transcriptomic level following repetitive exposure have not been investigated yet. Therefore, in this study, we aimed to dissect persistent changes in expression of microRNA-directed regulatory networks from transient transcriptome modifications contributing to AFB1-induced HCC. Primary human hepatocytes were exposed to 1 µM of AFB1 for 5 days followed by a 3 day wash-out period. Whole genome transcriptomic analysis and microRNA expressions were analyzed applying microarray technologies. By evaluating genes which remain significantly expressed into the same direction after the 3-day wash-out period persistent AFB1-induced and HCC-related biological processes could be identified. Persistent genes could be linked with "Drug and energy metabolism" and "Pre-, post- and transcriptional regulation of gene expression" related processes. Especially, two HCC-related microRNAs, hsa-miR-34b-5p and hsa-miR-222-3p, which are persistently expressed, seem to regulate genes involved in these very characteristic AFB1-induced processes referring to cancer-associated metabolism changes and regulation of gene expression. Moreover, hsa-miR-34a-5p, hsa-miR-96-5p and hsa-miR-30a-3p which become differentially expressed only upon terminating AFB1 exposure, seem to regulate persistently expressed genes. The findings within this study therefore contribute to a better understanding of the AFB1-induced onset of HCC by causing persistent effects on microRNA and gene expression.
Project description:Hepatocellular carcinoma (HCC), one of the most common cancer types, is a multi-factorial disease. One strongly associated factor is oral exposure to the food-contaminant aflatoxin B1 (AFB1). A clear link between AFB1-induced p53 mutations and HCC exists, however less is known about the association with microRNA expression changes. In particular, irreversible adverse effects that may occur at the transcriptomic level following repetitive exposure have not been investigated yet. Therefore, in this study, we aimed to dissect persistent changes in expression of microRNA-directed regulatory networks from transient transcriptome modifications contributing to AFB1-induced HCC. Primary human hepatocytes were exposed to 1 µM of AFB1 for 5 days followed by a 3 day wash-out period. Whole genome transcriptomic analysis and microRNA expressions were analyzed applying microarray technologies. By evaluating genes which remain significantly expressed into the same direction after the 3-day wash-out period persistent AFB1-induced and HCC-related biological processes could be identified. Persistent genes could be linked with "Drug and energy metabolism" and "Pre-, post- and transcriptional regulation of gene expression" related processes. Especially, two HCC-related microRNAs, hsa-miR-34b-5p and hsa-miR-222-3p, which are persistently expressed, seem to regulate genes involved in these very characteristic AFB1-induced processes referring to cancer-associated metabolism changes and regulation of gene expression. Moreover, hsa-miR-34a-5p, hsa-miR-96-5p and hsa-miR-30a-3p which become differentially expressed only upon terminating AFB1 exposure, seem to regulate persistently expressed genes. The findings within this study therefore contribute to a better understanding of the AFB1-induced onset of HCC by causing persistent effects on microRNA and gene expression.
Project description:Chronic exposure to aflatoxin B1 (AFB1) has, in certain regions in the world, been strongly associated with the development of hepatocellular carcinoma (HCC). AFB1 is a very potent hepatotoxic and carcinogenic mycotoxin which is frequently reported as a food contaminant. Epigenetic modifications provoked by environmental exposures, such as AFB1, may create a so called persistent "epigenetic memory" or "footprint". Deregulation of epigenetic mechanisms has actually been reported in HCC patients following AFB1 exposure; however no attempts have yet been made to investigate early effects on the epigenome level which may be persistent on longer term thereby possibly initiating carcinogenic events. In this study, we aim to identify methyl DNA-mRNA-interactions representative for a persistent epigenetic "footprint" associated with the early onset of AFB1-induced HCC. For this, primary human hepatocytes were exposed to 0.3 µM of AFB1 for 5 days. Persistent epigenetic effects were m easured 3 days after terminating the carcinogenic treatment. Whole genome DNA methylation changes and whole genome transcriptomic analysis were analyzed applying microarray technologies, and cross-omics interactions were evaluated. Upon combining transcriptomics data with results on DNA methylation, a range of persistent hyper- and hypomethylated genes was identified which appeared also affected on the transcriptome level. For six of the hypomethylated and upregulated genes, namely TXNRD1, PCNA, CCNK, DIAPH3, RAB27A and HIST1H2BF, a clear role in carcinogenic events could be identified. This study is the first to report on a carcinogen-induced persistent impact on the "epigenetic footprint" in relation with the transcriptome which could be indicative for the early onset of AFB1-related development of HCC.
Project description:Chronic exposure to aflatoxin B1 (AFB1) has, in certain regions in the world, been strongly associated with the development of hepatocellular carcinoma (HCC). AFB1 is a very potent hepatotoxic and carcinogenic mycotoxin which is frequently reported as a food contaminant. Epigenetic modifications provoked by environmental exposures, such as AFB1, may create a so called persistent "epigenetic memory" or "footprint". Deregulation of epigenetic mechanisms has actually been reported in HCC patients following AFB1 exposure; however no attempts have yet been made to investigate early effects on the epigenome level which may be persistent on longer term thereby possibly initiating carcinogenic events. In this study, we aim to identify methyl DNA-mRNA-interactions representative for a persistent epigenetic "footprint" associated with the early onset of AFB1-induced HCC. For this, primary human hepatocytes were exposed to 0.3 µM of AFB1 for 5 days. Persistent epigenetic effects were m easured 3 days after terminating the carcinogenic treatment. Whole genome DNA methylation changes and whole genome transcriptomic analysis were analyzed applying microarray technologies, and cross-omics interactions were evaluated. Upon combining transcriptomics data with results on DNA methylation, a range of persistent hyper- and hypomethylated genes was identified which appeared also affected on the transcriptome level. For six of the hypomethylated and upregulated genes, namely TXNRD1, PCNA, CCNK, DIAPH3, RAB27A and HIST1H2BF, a clear role in carcinogenic events could be identified. This study is the first to report on a carcinogen-induced persistent impact on the "epigenetic footprint" in relation with the transcriptome which could be indicative for the early onset of AFB1-related development of HCC.
Project description:Chronic exposure to aflatoxin B1 (AFB1) has, in certain regions in the world, been strongly associated with the development of hepatocellular carcinoma (HCC). AFB1 is a very potent hepatotoxic and carcinogenic mycotoxin which is frequently reported as a food contaminant. Epigenetic modifications provoked by environmental exposures, such as AFB1, may create a so called persistent "epigenetic memory" or "footprint". Deregulation of epigenetic mechanisms has actually been reported in HCC patients following AFB1 exposure; however no attempts have yet been made to investigate early effects on the epigenome level which may be persistent on longer term thereby possibly initiating carcinogenic events. In this study, we aim to identify methyl DNA-mRNA-interactions representative for a persistent epigenetic "footprint" associated with the early onset of AFB1-induced HCC. For this, primary human hepatocytes were exposed to 0.3 µM of AFB1 for 5 days. Persistent epigenetic effects were m easured 3 days after terminating the carcinogenic treatment. Whole genome DNA methylation changes and whole genome transcriptomic analysis were analyzed applying microarray technologies, and cross-omics interactions were evaluated. Upon combining transcriptomics data with results on DNA methylation, a range of persistent hyper- and hypomethylated genes was identified which appeared also affected on the transcriptome level. For six of the hypomethylated and upregulated genes, namely TXNRD1, PCNA, CCNK, DIAPH3, RAB27A and HIST1H2BF, a clear role in carcinogenic events could be identified. This study is the first to report on a carcinogen-induced persistent impact on the "epigenetic footprint" in relation with the transcriptome which could be indicative for the early onset of AFB1-related development of HCC.