Sequence Level Analysis of Double Minute Chromosomes in the Ovarian Cancer Cells Yields Insights into Their Complicated Molecular Architecture

We established optimal conditions for two-dimensional pulsed field gel electrophoresis and purified DMs from ovarian cancer cell line UACC-1598. The DMs in the cancer cells are heterogeneous in size (1–3 Mb), and the purified DNA molecules were confirmed as intracellular DMs using fluorescence in situ hybridization on metaphase chromosome. The entire genetic landscape of DMs was determined by second-generation sequencing technology. We found that DMs arised from multiple chromosomal regions (including four major amplified fragments from 1q21.2, 2p24.3, 3q26.2 and 6p22.3), and were heavily rearranged with 157 rearrangement junctions.