The 3D chromatin landscape of rhabdomyosarcoma [ChIP-Seq]

Rhabdomyosarcoma (RMS) is a pediatric soft tissue cancer with no precision therapy available for affected patients. We hypothesized that with a general paucity of known mutations in RMS, chromatin structural driving mechanisms are essential for tumor proliferation. Thus, we carried out high-depth in situ Hi-C in representative cell lines and patient-derived xenografts to understand chromatin architecture in each major RMS subtype. We report a comprehensive 3D chromatin structural analysis and characterization of fusion-positive (FP-RMS) and fusion-negative rhabdomyosarcoma (FN-RMS). We have generated spike-in in situ Hi-C chromatin interaction maps for the commonest FP-RMS and FN-RMS cell lines, and compared our data with patient derived xenograft (PDX) models. In our studies we uncover common and distinct structural elements in large Mb-scale chromatin compartments, tumor-essential genes within variable topologically associating domains, and unique patterns of structural variation. This study enables a comprehensive resource for contextualizing gene regulation events in RMS, and high-depth chromatin interactivity maps for identification of functionally critical chromatin domains in this tumor. Genomic localization of CTCF, MYOD1, and H3K27ac, and H3K9me3 in rhabdomyosarcoma cell lines by ChIP-seq