Das Epigenom: Zielstruktur für innovative Therapiekonzepte beim Kopf- und Halskarzinom

Dysregulation of protein argininemethyltransferase in the pathogenesis of cancerpy

Arginine methylation is considered to be one of the most permanent and one of the most frequent post-translational modifications. The reaction of transferring a methyl group from S-adenosylmethionine to arginine residue is catalyzed by aginine methyltransferase (PRMT). In humans there are nine members of the PRMT family, named in order of discovery of PRMT1- PRMT9. Arginine methyltransferases were divided into three classes: I, II, III, with regard to the product of the catalyzed reaction. The products of their activity are, respectively, the following: asymmetric dimethylarginine (ADMA), symmetrical dimethylarginine (SDMA) and monomethylarginine (MMA). These modifications significantly affect the chromatin functions; therefore, they can act as co-activators or suppressors of the transcription process. Arginine methylation plays a crucial role in many biological processes in a human organism. Among others, it participates in signal transduction control, mRNA splicing and the regulation of basic cellular processes such as proliferation, differentiation, migration and apoptosis. There is increasing evidence that dysregulation of PRMT levels may lead to the cancer transformation of cells. The correlation between increased PRMT level and cancer has been demonstrated in the following: breast, ovary, lung and colorectal cancer. The activity of arginine methyltransferase can be regulated by small molecule PRMT inhibitors. To date, three substances that inhibit PRMT activity have been evaluated in clinical trials and exhibit anti-tumor activity against hematological cancer. It is believed that the use of specific PRMT inhibitors may become a new, effective and safe treatment of oncological diseases.

Comprehensive Analysis of DNA Methylation and Gene Expression Datasets Identified MMP9 and TWIST1 as Important Pathogenic Genes of Lung Adenocarcinoma

Due to the high mortality of lung cancer, early diagnosis followed by early effective treatment is the key to prognosis improvement, which demands to identify the biological targets. Therefore, a multistage screening analysis was used to identify biological targets of lung adenocarcinoma. Two independent datasets of DNA methylation and RNA expression microarray in lung adenocarcinoma and normal lung tissues were chosen from the Gene Expression Omnibus. The association between DNA methylation and gene expression was explored, and the prognostic value of the hub genes was also evaluated. In this study, 8533 differential methylation sites, mostly located in the CpG island region and corresponding to 2754 genes (referred as differential methylation genes), were detected from methylation microarray. Besides, we obtained 830 differential expression genes, including 570 downregulated and 260 upregulated genes, through differential expression analysis. Protein-protein interaction analysis identified CXCL12, GFR, KDR, MMP9, TEK, and TWIST as core nodes, involving in the process of tumor cell identification, cell growth, cytokine secretion, inflammatory response, and angiogenesis. Among them, MMP9 and TWIST1 were identified as more valuable biological targets for the early diagnosis and targeted therapy of lung cancer through Kaplan-Meier analysis of TCGA lung adenocarcinoma datasets. Our study should contribute to the diagnosis and treatment of lung adenocarcinoma.