Selective inhibition of HDAC6 regulates expression of the oncogenic driver EWSR1-FLI1 through the EWSR1 promoter in Ewing sarcoma
Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor of children and young adults in which the principal driver is a fusion gene, EWSR1-FLI1. Although the essential role of EWSR1-FLI1 protein in the regulation of oncogenesis, survival, and tumor progression processes has been described in-depth, little is known about the regulation of chimeric fusion-gene expression. Here, we demonstrate that the active nuclear HDAC6 in EWS modulates the acetylation status of specificity protein 1 (SP1), consequently regulating the SP1/P300 activator complex binding to EWSR1 and EWSR1-FLI1 promoters. Selective inhibition of HDAC6 impairs binding of the activator complex SP1/P300, thereby inducing…
Expression of insulin-like growth factor system components in Ewing's sarcoma and their association with survival.
Abstract Aims The role of IGF system in the pathogenesis of Ewing’s sarcoma (EWS) is well-documented. However, still little information is available about the value of IGF system components as indicators of prognosis. Understanding the clinical role for IGF system in EWS patients may be important because different subtypes of patients have distinct outcome and may require different treatment protocol. We evaluated the expression of insulin-like growth factor (IGF)-receptor (IGF-IR), insulin receptor (IR), IGF-I and some major intracellular mediators (IRS1, p-ERK) in specimens from EWS patients with primary localised untreated tumours. Patients and methods 290 samples were used for immunohis…