Project description:Upregulation of enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) and its associated histone H3 lysine 27 (H3K27) trimethylation frequently occur in human cancer, yet both preclinical and clinical evidence suggested the very limited benefit of EZH2-targeted therapies. This study investigated the underlying mechanisms from a perspective of EZH2 inhibition-caused histone modification crosstalk. A mass spectrometry approach enabled us discovering the alteration of global histone modifications responding to EZH2 inhibition. Feedback upregulation of H3K27 acetylation (H3K27ac) level is closely associated with limited drug response to EZH2 inhibition across multiple cancer types. H3K27ac alteration caused transcriptional activation of oncoproteins confers drug resistant to EZH2 inhibition. Here we used ChIP-Seq analysis to identify the alteration of genome-wide H3K27ac bingding sites with EZH2 inhibitor treatment in human cancer cell lines.
Project description:MCF-7 (Estrogen receptor positive breast cancer) cells were treated with p300 KAT inhibitor A-485 and genome wide H3K27ac deposition was measured by ChIP-seq.
Project description:The histone methyltransferase EZH2 has been shown to function as a multifaceted molecule which can switch from a transcriptional repressor to an activator inducing a subset of genes that promote oncogenesis, including breast cancer. TfR-1, a key mediator in iron absorption, is highly expressed in a variety of tumors and associated with tumor grade, tumor stage and prognosis of patients. However, the known regulation mechanism of TfR-1 mainly remains on post-transcriptional level. To figure out whether TfR-1 expression is under epigenetic control, we examined the influence of EZH2 depletion and inhibition on TfR-1 expression in different subtypes of breast cancer cells. We discovered that EZH2 context-dependently modulates TfR-1 level and manipulates cellular iron uptake. Moreover, we identified TfR-1 as an NF-κB target gene which is positively regulated by EZH2 via constructing a complex with p65-p50 and transcription factor AP-1 in ER- cells. Inversely, TfR-1 is repressed by EZH2 and ER through histone methylation on its promoter in ER+ cells. These findings demonstrated an additional role of EZH2 in promoting breast cancer progression through iron homeostasis regulation and underscore the need for developing context-specific strategy for therapeutic targeting of epigenetic inhibition in breast cancer.
Project description:A comparison of different energetics based techniques for the characterization of two mammalian breast cell lines, MCF-7 a luminal A breast cancer cell line and MCF-10A a normal human breast cell line. The techniques of stability of proteins from rates of oxidation (SPROX), thermal proteome profiling (TPP), and conventional expression level analyses were compared and the relative advantages and disadvantages are discussed.
Project description:Human breast cancer cell line MCF-7 is usually sensitive to chemotherapy drug BMS-554417, an insulin receptor (IR) and insulin-like growth factor receptor (IGFR) inhibitor. However, through step-wise increase in BMS-554417 doses in culture media, we were able able to screen and select a single MCF-7 clone that is BMS-554417 resistant. It is cross resistant to BMS-536924. This new line of MCF-7 cells was named as MCF-7R4. The transcriptome profiling of both MCF-7 and MCF-7R4 was performed using Affymetrix HG-U133 plus2.0 GeneChip arrays.
Project description:Previously, we have shown that HIST1H2ac is overexpressed in MCF-7 breast cancer cell line. It acts as a master regulator of estrogen receptor alpha-dependent gene expression in ER+ breast cancer cells. In the present study, we investigate the genome-wide protein DNA-binding events of HIST1H2ac protein in MCF-7 breast cancer cell line by over-expressing hemagglutinin (HA)-tagged HIST1H2ac and compared with MCF-7 cells over-expressing HA. The protein-bound DNA was recovered by immunoprecipitation using anti-HA antibody. The ChIP DNA and input DNA were sequenced with an Illumina HiSeq 2000 sequencer.