ChIP sequencing of cyclin D1 reveals a transcriptional role in chromosomal instability in mice

Abstract

Chromosomal instability (CIN) in tumors is characterized by chromosomal abnormalities and an altered gene expression signature; however, the mechanism of CIN is poorly understood. CCND1 (which encodes cyclin D1) is overexpressed in human malignancies and has been shown to play a direct role in transcriptional regulation. Here, we used genome-wide ChIP sequencing and found that the DNA-bound form of cyclin D1 occupied the regulatory region of genes governing chromosomal integrity and mitochondrial biogenesis. Adding cyclin D1 back to Ccnd1 -/-mouse embryonic fibroblasts resulted in CIN gene regulatory region occupancy by the DNAbound form of cyclin D1 and induction of CIN gene expression. Furthermore, increased chromosomal aberrations, aneuploidy, and centrosome abnormalities were observed in the cyclin D1-rescued cells by spectral karyotyping and immunofluorescence. To assess cyclin D1 effects in vivo, we generated transgenic mice with acute and continuous mammary gland-targeted cyclin D1 expression. These transgenic mice presented with increased tumor prevalence and signature CIN gene profiles. Additionally, interrogation of gene expression from 2,254 human breast tumors revealed that cyclin D1 expression correlated with CIN in luminal B breast cancer. These data suggest that cyclin D1 contributes to CIN and tumorigenesis by directly regulating a transcriptional program that governs chromosomal stability. IntroductionChromosomal instability (CIN) in tumors (1-3) is characterized by an elevated rate of gain or loss of whole chromosomes (i.e., aneuploidy) and/or as structural chromosomal aberrations (i.e., translocations, deletions, and duplications). Aneuploidy is one of the most striking differences between cancer and normal cells. The molecular mechanisms inducing CIN as well as the timing of CIN in tumor progression, invasion, and metastasis is poorly understood (4, 5). Cell cycle-associated factors have been implicated in CIN, including cyclin E (6). The relative enrichment of a molecular genetic signature of CIN-related genes has been used to quantitate a CIN score (7); this signature includes AURKB (a component of the chromosomal passenger complex [CPC]), TOP2A, CENPP, MLF1IP (a component of the CENPA-NAC kinetochore complex protein), ZW10 (a kinetochore-associated mitotic checkpoint protein), and CKAP2 (a mitotic spindle-associated protein) (3) as well as the retinoblastoma (pRb) protein. Supernumerary centrosomes increase the frequency of dual attachment of 1 sister kinetochore to 2 spindle poles. Cyclin E activity promotes centrosome duplication during S phase onset. Loss of pRb can also alter centrosome number and formation of micronuclei, leading to

Cyclin D1 Promotes Androgen-Dependent DNA Damage Repair in Prostate Cancer Cells

“…Previous studies examined transcriptional regulation of the cyclin D1 target genes, LPL, aP2 (49) and miR17/20 (50). ChIP-ChIP demonstrated cyclin D1 and p300 together occupied genes in close proximity to the transcriptional start site (51), and whole genome ChIP-Seq demonstrated enrichment of cyclin D1 at genes that regulate mitosis and chromosomal instability (CIN) in close proximity to the transcriptional start site (52). Together, these studies are consistent with a model in which cyclin D1 functions to regulate transcription in a cdk-independent manner.…”

Non-canonical functions of cell cycle cyclins and cyclin-dependent kinases

“…A direct interaction of cyclin D1 with chromatin was also demonstrated by a ChIP-sequencing study in which tagged cyclin D1 was ectopically expressed in cyclin D1-null mouse embryonic fibroblasts. The authors concluded that cyclin D1 plays a role in chromosomal stability through binding to genes that govern chromosomal integrity 52 .…”

Loss of Sirt1 Promotes Prostatic Intraepithelial Neoplasia, Reduces Mitophagy, and Delays Park2 Translocation to Mitochondria

“…Whole-cell lysates (50 mg) were separated by 10% SDS-PAGE gel, and the proteins were transferred to nitrocellulose membrane for Western blot analysis, as previously described, 31 and probed for SIRT1 (catalog number 15404; Santa Cruz Biotechnology), SOD2-AcK68 (provided by Dr. David Gius 29 ), and b-tubulin (catalog number T4026; Sigma-Aldrich).…”