Project description:Diffuse large B cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma, includes two main molecular subtypes: activated B cell-like (ABC) DLBCL and germinal center B cell-like (GCB) DLBCL. ABC DLBCL is more aggressive, with the activated JAK1-STAT3 pathway that promotes cell survival. In order to study the underlying pathogenic mechanism, we performed a ChIP-seq experiment by phospho-STAT3(Tyr705) antibody in ABC DLBCL cell lines, and identified 3,456 STAT3 target genes genome-wide. In parallel, ChIP-seq experiment was performed with STAT3 antibody in α-IgM stimulated naïve B cells for verification of these targets of STAT3 protein. TMD8 was treated by eithor DMSO or AZD1480 (JAK inhibitor) for 4hrs, ChIP-seq experiments were performed by pSTAT3(Tyr705) antibody (#9145S, Cell signaling). Naïve B cells were collected from peripheral blood mononuclear cells by Naive B Cell Isolation kit (miltenyi biotec; 130-091-150), and treated by 10ug/ml α-IgM (southernbiotech; #2020-01) for 24hrs. ChIP-seq experiments were performed by STAT3 antibody (SC-482X, Santa Cruz).
Project description:We report a novel approach to identify genome-wide somatic hypermutation hotspots from short Illumina H3K4me3 ChIPseq reads in diffuse large B-cell lymphoma cells (DLBCL). Abberant somatic hypermation are known to occur at the promoters of several proto-oncogenes in DLBCL. To identify such events genome-wide, we performed H3K4me3 ChIPseq experiments (as to enrich promoter sequences of actively transcribed genes) in 2 DLBCL cells lines (OCI-Ly1 and OCI-Ly8) and their normal B-cell counterparts, Naive B cells (NBC) and Germinal Center B cells (GCBs). We discover new genes that harbor mutations in their promoter regions that are potentially introduced by the aberrant activation-induced cytosine deaminase activity in lymphoma cell lines, and many of these genes are important for the B cell biology. Moreover, we show that these mutations can affect the activities of these promoters. Our study provides a feasible approach for the detection of promoter mutations and broadens our knowledge on promoter mutations in lymphomas.
