Project description:Amplification of the 8p11-p12 genomic region occurs in 30% of luminal B breast cancers and results in coordinate overexpression of several oncogenes, including ASH2L, which upregulates gene expression via promoter tri-methylation of lysine 4 on histone 3 (H3K4me3). Since 8p11-p12 amplification is associated with endocrine resistance, the major cause of breast cancer mortality, understanding the underlying biology is essential to improving treatment options for patients. To explore the role of amplified and overexpressed ASH2L on epigenetic regulation of gene expression, we performed H3K4me3 ChIP-seq and RNA-seq in breast cancer cells with ASH2L amplification and overexpression following ASH2L knockdown and assessed the biological effects of the suite of genes identified in this manner. We discovered that ASH2L-regulated genes are implicated in cell cycle processes and response to the CDK4/6 inhibitor palbociclib and confirmed these effects in additional breast cancer cell lines. We also discovered that ASH2L regulates expression of another 8p11-p12 amplicon oncogene NSD3, also an epigenome modifier, which has previously been shown to result in overexpression and estrogen-independent activation of ERα. Together, these data establish ASH2L as a breast cancer oncogene and an important component of the 8p11-p12 amplicon that acts as an oncogenic unit in breast cancer.
Project description:RNA-sequencing analysis of CDK12 overexpressiong ZR-75-30 cell lines. Cyclin dependent kinase 12 (CDK12) is amplified in approximately 70-90% of HER2 amplified breast cancer. Results provide insight into the targets of CDK12 in HER2 positive breast cancer.
Project description:CTCF, H2AFZ and FOXA1 genomic recruitment sites were determined using ChIP-chip while MeDIP-chip was used to monitor DNA methylation levels. Amplified and labeled DNA was hybridized to Affymetrix tiling arrays covering human chromosomes 8, 11 and 12. Cells used in this study are: MCF7 breast cancer cells, LNCaP prostate cancer cells, MDA-MB-231 breast cancer cells stably transfected with a FOXA1 expression vector (MDA231-FOXA1) or the empty control plasmid (MDA231-CTRL). H3K4me2 genomic distribution was determined using ChIP-chip. Amplified and labeled DNA was hybridized to Affymetrix tiling arrays covering human chromosomes 8, 11 and 12. Cells used in this study are MDA-MB-231 breast cancer cells stably transfected with a FOXA1 expression vector (MDA231-FOXA1) or the empty control plasmid (MDA231-CTRL).
Project description:The eIF4E translation initiation factor has oncogenic properties and concordantly, the inhibitory eIF4E-binding protein (4EBP1) is considered a tumor suppressor. The exact molecular effects of 4EBP1 activation in cancer are still unknown. Surprisingly, 4EBP1 is a target of genomic copy number gains (Chr. 8p11) in breast and lung cancer. We notice that 4EBP1 gains are genetically linked to gains in neighboring genes including WHSC1L1 and FGFR1. Our results show that FGFR1 gains act to attenuate the function of 4EBP1 via PI3K mediated phosphorylation at Thr37/46, Ser65, and Thr70 sites. This implies that not 4EBP1 but instead FGFR1 is the genetic target of Chr. 8p11 gains in breast and lung cancer. Accordingly, these tumors show increased sensitivity to FGFR1 and PI3K inhibition and this is a therapeutic vulnerability through restoring the tumor-suppressive function of 4EBP1. Ribosome profiling reveals genes involved in insulin signaling, glucose metabolism, and inositol pathway to be the relevant translational targets of 4EBP1. These mRNAs are among the top 200 translation targets and are highly enriched for structure and sequence motifs in their 5’UTR that depends on the 4EBP1-EIF4E activity. In summary, we identify the translational targets of 4EBP1-EIF4E that facilitate the tumor suppressor function of 4EBP1 in cancer.
Project description:Co-amplification at chromosomes 8p11-8p12 and 11q12-11q14 occurs often in breast tumors, suggesting possible cooperation between genes in these regions in oncogenesis. We used high resolution array comparative genomic hybridization (array CGH) to map the minimal amplified regions. The 8p and 11q amplicons are complex and consist of at least four amplicon cores at each site. Candidate genes mapping to these regions were identified by combining copy number and RNA and protein expression analyses. Funcational analysis for transformation was further carried out with candidate genes to determine candidate oncogenes. Near tiling path coverage of 8p11q array CGH experiments with breast cell lines and ductal invasive and lymph node-negative breast tumors.