Identification of recurrent chromosome breaks underlying structural rearrangements in mammary cancer cell lines [Break-seq]

ABSTRACT: Cancer genomes are characterized by accumulation of small-scale somatic mutations as well as large-scale chromosomal deletions, amplifications, and complex structural rearrangements. This characteristic is at least partially dependent on the ability of cancer cells to undergo recurrent chromosome breakage. In order to address to what extent chromosomal structural rearrangement breakpoints correlate with recurrent DNA double strand breaks (DSBs), we simultaneously mapped chromosome structural variation breakpoints by whole genome DNA-seq and spontaneous DSB formation by Break-seq in the breast cancer cell line MCF-7 and a non-cancer control cell line MCF-10A. We identified concurrent DSBs and structural variation breakpoints almost exclusively in the pericentromeric region of chromosome 16q in MCF-7 cells. We fine-tuned the identification of copy number variation breakpoints on 16q. In addition, we detected recurrent DSBs that occurred in both MCF-7 and MCF-10A. We propose a model for DSB-driven chromosome rearrangements that led to the translocation of 16q, likely with 10q, and the eventual 16q loss that does not involve the pericentromere of 16q. We present evidence from RNA-seq data that select genes, including SHCBP1, ORC6 and MYLK3, which are immediately downstream from the 16q pericentromere show heightened expression in MCF-7 cell line compared to the control. Data published by The Cancer Genome Atlas showed that all three genes have increased expression in breast tumor samples. We suggest that these genes are potential oncogenes for breast cancer progression. The search for tumor suppressor loss that accompanies the 16q loss ought to be augmented by the identification of potential oncogenes that gained expression during chromosomal rearrangements.

ORGANISM(S): Homo sapiens

PROVIDER: GSE207714 | GEO | 2022/07/12

REPOSITORIES: GEO