Project description:We hypothesize that knockdown or inhibition of the EZH2 results in decreased proliferation and tumorigenic potential of TNBC breast cancer cells
Project description:Despite advances in our understanding of the underlying genetic abnormalities in myelofibrosis (MF) and the development of JAK2 inhibitors, there is an urgent need to devise new treatment strategies, particularly in triple negative MF patients who lack mutations in the JAK2 kinase pathway. Here we report that MYC copy number gain (e.g., trisomy 8) is frequently identified in triple negative MF where MF development and progression rely on MYC-directed activation of S100A9, a Danger Associated Molecular Pattern (DAMP) protein that plays pivotal roles in inflammation. Notably, MYC-S100A9 axis underlies complex network of inflammatory signaling that involves various hematopoietic cell types in the bone marrow microenvironment. Accordingly, small molecules targeting the MYC-S100A9 pathway effectively ameliorated the MF phenotypes, highlighting MYC-alarmin axis as a novel therapeutic vulnerability in a subgroup of MF patients.
Project description:Triple-negative breast cancer cell line SUM-149 xenograft mouse model was treated with CDK2 inhibitor (dinaciclib) and EZH2 inhibitor (EPZ6438) for 10 days to examine global transcriptome alternations by RNAseq. Expression levels of more than 801 and 741 gene were altered by CDK2 inhibitor and EZH2 inhibitor treatment, respectively.Among differential changed genes induced by CDK2 inhibitor and EZH2 inhibitor, we defined top 109 common up- and down-regulated gene sets in the inhibitor-treated tumors.
Project description:Mutations or aberrant upregulation of the histone methyltransferase EZH2 occur frequently in human cancers yet EZH2-targeted therapies have only shown very limited clinical benefits in hematological malignancies. We report here that upon EZH2 inhibition, MLL1 interacts with p300/CBP complex that directs H3K27me loss to gain of H3K27ac modification. This histone modification crosstalk leads to transcriptional reprogramming that restricts the therapeutic response to EZH2 inhibition. Concurrent inhibition of H3K27 methylation and acetylation results in transcriptional repression and growth dependency on the MAPK signaling pathway in a large cancer subset. In pre-clinical models encompassing a broad spectrum of EZH2-aberrant solid tumors, a combination of EZH2 and BRD4 inhibitors or a triple-combination including MAPK inhibition display robust efficacy with tolerable toxicity, in particular in liver and pancreatic cancers. Our results suggest an attractive precision treatment and patient stratification strategy for EZH2-aberrant tumors on the basis of intrinsic MLL1 expression and feedback MAPK activation.
Project description:Overexpression of EZH2 in estrogen receptor negative (ER-) breast cancer promotes metastasis. EZH2 has been mainly studied as the catalytic component of the Polycomb Repressive Complex 2 (PRC2) that mediates gene repression by trimethylating histone H3 at lysine 27 (H3K27me3). However, how EZH2 drives metastasis despite the low H3K27me3 levels observed in ER- breast cancer is unknown. We have shown that in human invasive carcinomas and distant metastases, cytoplasmic EZH2 phosphorylated at T367 is significantly associated with ER- disease and low H3K27me3 levels. Here, we explore the interactome of EZH2 and of a phosphodeficient mutant EZH2_T367A. We identified novel interactors of EZH2, and identified interactions that are dependent on the phosphorylation and cellular localization of EZH2 that may play a role in EZH2 dependent metastatic progression.